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January 26, 2021
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https://www.sciencedaily.com/releases/2021/01/210126140106.htm
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Invasive mussels now control a key nutrient in the American Great Lakes
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The health of aquatic ecosystems depends on the supply of key nutrients, especially phosphorus. Too much phosphorus results in unwanted eutrophication, and much effort is spent on preventing phosphorus pollution of water bodies. In the World's largest freshwater ecosystem, the North American Great Lakes, this control may have recently been lost to an invasive species. According to a new study, quagga mussels, which have spread across four of the five Great Lakes, have accumulated large amounts of phosphorus in their biomass, to the degree that their activities now regulate the supply of phosphorus to the ecosystem.
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The invaders, native to the Ponto-Caspian region of Eurasia, appeared in the Great Lakes in the late 1980's and by late 2000's spread over vast areas of bottom sediments in all the lakes except Lake Superior. Their biological effects on the ecosystem have been well recognized, but effects on the chemical system remained uncertain.Researchers from the Large Lakes Observatory, University of Minnesota Duluth analyzed the cycling of phosphorus in lakes Michigan, Huron, Erie, and Ontario. They used a mass-balance model, which they calibrated with measurements that the team performed on sediments and mussels at multiple locations in Lakes Michigan and Huron. The results show that the concentrations of phosphorus in the invaded Great Lakes are now regulated by the population dynamics of a single benthic species, the quagga mussel."Quagga mussels are small, hard-shelled organisms that live on the lake floor and filter the water, removing the phytoplankton and other small particles," explains Ted Ozersky, an Associate Professor of Biology who co-led the study. By now they occupy the lake floor at densities often exceeding 10,000 individuals per square meter (6 mussels per square inch). "In terms of biomass, quagga mussels are the dominant life form in the Great Lakes," says Sergei Katsev, a Professor at the Large Lakes Observatory who oversaw the geochemical aspects of the research.By filtering organic particles from the lake water and recycling phosphorus back with their excretions and feces, mussels dramatically alter the natural rates at which phosphorus is exchanged between lake water and sediments. According to the study, the mussels in Lake Michigan are not only removing phosphorus from the water ten times faster than two decades ago, but are also resupplying the water column with eight times the amount of phosphorus that reaches the lake from the entire watershed. This kind of "internal loading" effectively decouples the dynamics of phosphorus from watershed inputs, leaving the system open to poorly predictable fluctuations when mussel populations increase or decrease."The mussels have short-circuited the normal pathways of the phosphorus cycling in the lakes," explains the lead author Jiying Li, formerly a postdoctoral researcher at UMD and presently an Assistant Professor at the Hong Kong University of Science and Technology. "And the productivity in the lakes is now tied to what the mussel populations are doing."Growing populations of mussels are capable of absorbing large quantities of phosphorus from the water column, which is partly responsible for the water in the Great Lakes becoming clearer over recent years. In contrast, mortality events are capable of releasing large quantities of phosphorus back into the ecosystem. As a result, phosphorus becomes regulated by the dynamics of mussel populations and may respond only slowly to our efforts to control the runoff of phosphorus from the watershed.The results of the study, which appears in this week's The study was funded by the US National Science Foundation grant OCE-1737368.
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Environment
| 2,021 |
January 26, 2021
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https://www.sciencedaily.com/releases/2021/01/210126134041.htm
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Solar hydrogen: Photoanodes made of alpha-SnWO4 promise high efficiencies
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Photoanodes made of metal oxides are considered to be a viable solution for the production of hydrogen with sunlight. α-SnWO
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Hydrogen is an important factor in a sustainable energy system. The gas stores energy in chemical form and can be used in many ways: as a fuel, a feedstock for other fuels and chemicals or even to generate electricity in fuel cells. One solution to produce hydrogen in a climate-neutral way is the electrochemical splitting of water with the help of sunlight. This requires photoelectrodes that provide a photovoltage and photocurrent when exposed to light and at the same time do not corrode in water. Metal oxide compounds have promising prerequisites for this. For example, solar water splitting devices using bismuth vanadate (BiVOTo achieve efficiencies beyond 9 %, new materials with a smaller band gap are needed. The metal oxide α-SnWOProtection against corrosion comes with a priceThin layers of nickel oxide (NiO"We studied samples with different thicknesses of NiOOutlook: better protection layersOverall, the study provides new, fundamental insights into the complex nature of interfaces in metal oxide-based photoelectrodes. "These insights are very helpful for the development of low-cost, scalable metal oxide photoelectrodes," says Abdi. α-SnWO
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Environment
| 2,021 |
January 26, 2021
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https://www.sciencedaily.com/releases/2021/01/210126102803.htm
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Beauty in imperfection: How crystal defects can help convert waste heat into electricity
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If we are to prevent the impending environmental crisis, it is imperative that we find efficient and sustainable ways to avoid being wasteful. One area with much room for improvement is the recycling of waste heat from industrial processes and technological devices into electricity. Thermoelectric materials are at the core of research in this field because they allow for clean power generation at little cost.
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For thermoelectric materials to be used in vastly different fields such as steel works and transportation, they need to be able to operate in both high and low temperature regimes. In this regard, "half-Heusler Ni-based alloys" are currently under the spotlight thanks to their attractive thermoelectric efficiency, mechanical strength, and durability. Though much effort has been devoted to understanding and improving upon these peculiar alloys, scientists have found it difficult to clarify why half-Heusler Ni-based alloys have such a high conversion efficiency. Some have theorized that defects in the material's crystal structure increase its thermal conductivity and, in turn, its conversion efficiency. However, the crystal structure around the defects is unknown and so are their specific contributions.In a recent study published in Using these techniques, the team first calculated the structural effects that an additional Ni atom (defect) would have in the arrangement of NiZrSn crystals. Then, they verified the theoretical predictions through different types of XAFS measurements, as Dr. Miyazaki explains, "In our theoretical framework, we assumed crystal lattice distortions to be a consequence of atomic defects to perform first-principles band structure calculations. XAFS made it possible to obtain detailed information on the local crystal structure around atomic defects by comparing the experimental and theoretical spectra of the crystal structure." These observations allowed the scientists to accurately quantify the strain that Ni defects cause in nearby atoms. They also analyzed the mechanisms by which these alterations give rise to a higher thermal conductivity (and conversion efficiency).The results of this study will be crucial in advancing thermoelectric technology, as Dr. Miyazaki remarks: "We expect that our results will contribute to the development of a strategy centered around controlling the strain around defective atoms, which in turn will allow us to engineer new and better thermoelectric materials." Hopefully, this will lead to a leap in thermoelectric conversion technology and hasten the transition to a less wasteful, decarbonized society -- one in which excess heat is not simply discarded but instead recovered as an energy source.On a final note, Dr. Miyazaki highlights that the techniques used to observe fine changes in strain in crystalline structures can be readily adapted to other types of material, such as those intended for spintronic applications and catalysts.There is certainly much to gain from going after the fine details in materials science, and we can rest assured that this study marks a step in the right direction toward a better future!
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Environment
| 2,021 |
January 26, 2021
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https://www.sciencedaily.com/releases/2021/01/210126102814.htm
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Energy spent avoiding humans associated with smaller home ranges for male pumas
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A new paper from UC Santa Cruz researchers, published in
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"Mountain lions fear us, and that fear has all kinds of impacts on their behavior and ecology, and ultimately, potentially even their populations and conservation," said professor Chris Wilmers, the senior author on the paper.Wilmers is principal investigator for the Santa Cruz Puma Project, through which he and colleagues have been studying local mountain lion populations for over a decade. Barry Nickel, director of UC Santa Cruz's Center for Integrated Spatial Research, led the most recent study, which relied on data from five adult female pumas and eight adult males that were outfitted with tracking collars as they roamed their natural habitats.Throughout the two-month study period, the tracking collars recorded high-resolution GPS and accelerometer data, which Wilmers said worked "essentially like a Fitbit" to help the team estimate how many calories a mountain lion burned based on where, how far, and how fast the cat was moving. The ultimate goal was to integrate the energy cost of navigating physical terrain with the cost of avoiding humans to see how both factors affect use of habitats.To assess the impacts of physical terrain, researchers compared topography with trends in the cats' movement data. This showed that less rugged terrain requires less energy for pumas to navigate, which may help to explain why mountain lions prefer habitats with easy-to-traverse valleys or ridges. And to get a sense for how fear of humans affected the cats, researchers also compared housing densities with collar tracking data.This analysis showed that, in areas with higher housing densities, pumas were engaging in more energetically demanding movements, like stopping less and moving more quickly. Their movements were also much less efficient: instead of taking the shortest path to their destination, they took longer, meandering paths to navigate around perceived risks."Humans, as a risk factor, are actually increasing the energy an animal needs to traverse this landscape," Nickel explained. "And this is primarily through changes in their behavior as a means to avoid humans."The constant vigilance that cats used as they moved through human-dominated landscapes is incredibly energy intensive. Nickel and the research team estimate that, in otherwise identical terrain, pumas expend 13 percent more calories per five-minute period in habitats close to people than they would in remote wildland habitats.As a result, researchers found that fear of humans had a greater impact than variations in terrain on the amount of energy it takes for mountain lions to move about their habitats. In fact, the effect of increasing housing density on energetic costs of movement was four to 10 times greater than the effect of increasing slope and ruggedness of the terrain.That's a problem because pumas might compensate for increased energy costs in navigating their habitats by reducing the total size of their territories. And this trend showed up very clearly in the tracking data.Both males and females reduced the size of their home ranges in response to overall increased energy costs of navigating the landscape, but males, in particular, were especially affected by housing density. Male pumas in habitats most dominated by humans had 78.8 percent smaller home ranges compared to those with the most remote habitats.Human-induced risk has actually become the primary driver of male patterns of space use among pumas. Females didn't show this same trend, but the research team suspects males may be more vulnerable to human impacts because they typically have to establish larger home ranges to improve their odds of finding a mate.Overall, researchers are concerned that pressure to avoid humans may harm the health of local mountain lion populations."It constrains their space use, which could then affect other aspects of their ecology, like finding mates, finding food, competing with other males, or other natural interactions," Nickel said.
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Environment
| 2,021 |
January 25, 2021
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https://www.sciencedaily.com/releases/2021/01/210125113124.htm
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Street trees close to the home may reduce the risk of depression
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Depression, especially in urban areas, is on the rise, now more than ever. Mental health outcomes are influenced by, among other things, the type of environment where one lives. Former studies show that urban greenspace has a positive benefit on people experiencing mental ill health, but most of these studies used self-reported measures, which makes it difficult to compare the results and generalise conclusions on the effects of urban greenspace on mental health.
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An interdisciplinary research team of UFZ, iDiv and Leipzig University tried to improve this issue by involving an objective indicator: prescriptions of antidepressants. To find out whether a specific type of 'everyday' green space -- street trees dotting the neighbourhood sidewalks -- could positively influence mental health, they focused on the questions, how the number and type of street trees and their proximity close to home correlated to the number of antidepressants prescribed.The researchers analysed data from almost 10,000 Leipzig inhabitants, a mid-size city in Germany, who took part in the LIFE-Adult health study running at the University of Leipzig Medical Faculty. Combining that with data on the number and species type of street trees throughout the city of Leipzig, the researchers were able to identify the association between antidepressants prescriptions and the number of street trees at different distances from people's homes. Results were controlled for other factors known to be associated with depression, such as employment, gender, age, and body weight.More trees immediately around the home (less than 100 meters) was associated with a reduced risk of being prescribed antidepressant medication. This association was especially strong for deprived groups. As these social groups are at the greatest risk for being prescribed antidepressants in Germany, street trees in cities can thereby serve as a nature-based solution for good mental health, the researchers write. At the same time, street trees may also help reduce the 'gap' in health inequality between economically different social groups. No association of tree types, however, and depression could be shown in this study."Our finding suggests that street trees -- a small scale, publicly accessible form of urban greenspace -- can help close the gap in health inequalities between economically different social groups," says lead author of the study Dr Melissa Marselle. "This is good news because street trees are relatively easy to achieve and their number can be increased without much planning effort." As an environmental psychologist, she conducted the research at UFZ and iDiv and is now based at the De Montford University of Leicester, UK. Marselle hopes that the research "should prompt local councils to plant street trees to urban areas as a way to improve mental health and reduce social inequalities. Street trees should be planted equally in residential areas to ensure those who are socially disadvantaged have equal access to receive its health benefits.""Importantly, most planning guidance for urban greenspace is often based on purposeful visits for recreation," adds Dr Diana Bowler (iDiv, FSU, UFZ), data analyst in the team. "Our study shows that everyday nature close to home -- the biodiversity you see out of the window or when walking or driving to work, school or shopping -- is important for mental health." This finding is especially now in times of the COVID-19 lock-downs, Bowler adds.And it's not only human health which could benefit. "We propose that adding street trees in residential urban areas is a nature-based solution that may not only promote mental health, but can also contribute to climate change mitigation and biodiversity conservation," says senior author Prof Aletta Bonn, who leads the department of ecosystem services at UFZ, iDiv and Friedrich-Schiller-University Jena. "To create these synergy effects, you don't even need large-scale expensive parks: more trees along the streets will do the trick. And that's a relatively inexpensive measure.""This scientific contribution can be a foundation for city planners to save and, possibly, improve the life quality for inhabitants, in particular, in densely populated areas and in central city areas," adds Prof Toralf Kirsten from Leipzig University. "Therefore, this aspect should be taken into account when city areas are recreated and planned, despite high and increasing land cover costs. A healthy life of all living being is unaffordable."
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Environment
| 2,021 |
January 25, 2021
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https://www.sciencedaily.com/releases/2021/01/210125113102.htm
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New route to chemically recyclable plastics
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As the planet's burden of rubber and plastic trash rises unabated, scientists increasingly look to the promise of closed-loop recycling to reduce waste. A team of researchers at Princeton's Department of Chemistry announces the discovery of a new polybutadiene molecule -- from a material known for over a century and used to make common products like tires and shoes -- that could one day advance this goal through depolymerization.
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The Chirik lab reports in In other words, the butadiene can be "zipped up" to make a new polymer; that polymer can then be unzipped back to a pristine monomer to be re-used.The research is still at an early stage and the material's performance attributes have yet to be thoroughly explored. But the Chirik lab has provided a conceptual precedent for a chemical transformation not generally thought practical for certain commodity materials.In the past, depolymerization has been accomplished with expensive niche or specialized polymers and only after a multitude of steps, but never from a raw material as common as that used to make polybutadiene, one of the top seven primary petrochemicals in the world. Butadiene is an abundant organic compound and a major byproduct of fossil fuel development. It is used to make synthetic rubber and plastic products."To take a really common chemical that people have been studying and polymerizing for many decades and make a fundamentally new material out of it -- let alone have that material have interesting innate properties -- not only is that unexpected, it's really a big step forward. You wouldn't necessarily expect there still to be fruit on that tree," said Alex E. Carpenter, a staff chemist with ExxonMobil Chemical, a collaborator on the research."The focus of this collaboration for us has been on developing new materials that benefit society by focusing on some new molecules that [Princeton chemist] Paul Chirk has discovered that are pretty transformative," Carpenter added."Humankind is good at making butadiene. It's very nice when you can find other useful applications for this molecule, because we have plenty of it."The Chirik lab explores sustainable chemistry by investigating the use of iron -- another abundant natural material -- as a catalyst to synthesize new molecules. In this particular research, the iron catalyst clicks the butadiene monomers together to make oligocyclobutane. But it does so in a highly unusual square structural motif. Normally, enchainment occurs with an S-shaped structure that is often described as looking like spaghetti.Then, to affect depolymerization, oligocyclobutane is exposed to a vacuum in the presence of the iron catalyst, which reverses the process and recovers the monomer. The Chirik lab's paper, "Iron Catalyzed Synthesis and Chemical Recycling of Telechelic, 1,3-Enchained Oligocyclobutanes," identifies this as a rare example of closed-loop chemical recycling.The material also has intriguing properties as characterized by Megan Mohadjer Beromi, a postdoctoral fellow in the Chirik lab, together with chemists at ExxonMobil's polymer research center. For instance, it is telechelic, meaning the chain is functionalized on both ends. This property could enable it to be used as a building block in its own right, serving as a bridge between other molecules in a polymeric chain. In addition, it is thermally stable, meaning it can be heated to above 250-degrees C without rapid decomposition.Finally, it exhibits high crystallinity, even at a low molecular weight of 1,000 grams per mol (g/mol). This could indicate that desirable physical properties -- like crystallinity and material strength -- can be achieved at lower weights than generally assumed. The polyethylene used in the average plastic shopping bag, for example, has a molecular weight of 500,000g/mol."One of the things we demonstrate in the paper is that you can make really tough materials out of this monomer," said Chirik, Princeton's Edwards S. Sanford Professor of Chemistry. "The energy between polymer and monomer can be close, and you can go back and forth, but that doesn't mean the polymer has to be weak. The polymer itself is strong."What people tend to assume is that when you have a chemically recyclable polymer, it has to be somehow inherently weak or not durable. We've made something that's really, really tough but is also chemically recyclable. We can get pure monomer back out of it. And that surprised me. That's not optimized. But it's there. The chemistry's clean."I honestly think this work is one of the most important things to ever come out of my lab," said Chirik.The project stretches back a few years to 2017, when C. Rose Kennedy, then a postdoc in the Chirik lab, noticed a viscous liquid accumulating at the bottom of a flask during a reaction. Kennedy said she was expecting something volatile to form, so the result spurred her curiosity. Digging into the reaction, she discovered a distribution of oligomers -- or nonvolatile products with a low molecular weight -- that indicated polymerization had taken place."Knowing what we knew about the mechanism already, it was pretty clear right away how this would be possible to click them together in a different or continuous way. We immediately recognized this could be something potentially extremely valuable," said Kennedy, now an assistant professor of chemistry at the University of Rochester.At that early point, Kennedy was enchaining butadiene and ethylene. It was Mohadjer Beromi who later surmised that it would be possible to remove the ethylene altogether and just use neat butadiene at elevated temperatures. Mohadjer Beromi "gave" the four-carbon butadiene to the iron catalyst, and that yielded the new polymer of squares."We knew that the motif had the propensity to be chemically recycled," said Mohadjer Beromi. "But I think one of the new and really interesting features of the iron catalyst is that it can do [2+2] cycloadditions between two dienes, and that's what this reaction essentially is: it's a cycloaddition where you're linking two olefins together to make a square molecule over and over again."It's the coolest thing I've ever worked on in my life."To further characterize oligocyclobutane and understand its performance properties, the molecule needed to be scaled and studied at a larger facility with expertise in new materials."How do you know what you made?" Chirik asked. "We used some of the normal tools we have here at Frick. But what really matters is the physical properties of this material, and ultimately what the chain looks like."For that, Chirik traveled to Baytown, Texas last year to present the lab's findings to ExxonMobil, which decided to support the work. An integrated team of scientists from Baytown were involved in computational modeling, X-ray scattering work to validate the structure, and additional characterization studies.The chemical industry uses a small number of building blocks to make most commodity plastic and rubber. Three such examples are ethylene, propylene, and butadiene. A major challenge of recycling these materials is that they often need to be combined and then bolstered with other additives to make plastics and rubbers: additives provide the performance properties we want -- the hardness of a toothpaste cap, for example, or the lightness of a grocery bag. These "ingredients" all have to be separated again in the recycling process.But the chemical steps involved in that separation and the input of energy required to bring this about make recycling prohibitively expensive, particularly for single-use plastics. Plastic is cheap, lightweight, and convenient, but it was not designed with disposal in mind. That, said Chirik, is the main, snowballing problem with it.As a possible alternative, the Chirik research demonstrates that the butadiene polymer is almost energetically equal to the monomer, which makes it a candidate for closed-loop chemical recycling.Chemists liken the process of producing a product from a raw material to rolling a boulder up a hill, with the peak of the hill as the transition state. From that state, you roll the boulder down the other side and end up with a product. But with most plastics, the energy and cost to roll that boulder backwards up the hill to recover its raw monomer are staggering, and thus unrealistic. So, most plastic bags and rubber products and car bumpers end up in landfills."The interesting thing about this reaction of hooking one unit of butadiene onto the next is that the 'destination' is only very slightly lower in energy than the starting material," said Kennedy. "That's what makes it possible to go back in the other direction."In the next stage of research, Chirik said his lab will focus on the enchainment, which at this point chemists have only achieved on average up to 17 units. At that chain length, the material becomes crystalline and so insoluble that it falls out of the reaction mixture."We have to learn what to do with that," said Chirik. "We're limited by its own strength. I would like to see a higher molecular weight."Still, researchers are excited about the prospects for oligocyclobutane, and many investigations are planned in this continuing collaboration towards chemically recyclable materials."The current set of materials that we have nowadays doesn't allow us to have adequate solutions to all the problems we're trying to solve," said Carpenter. "The belief is that, if you do good science and you publish in peer-reviewed journals and you work with world-class scientists like Paul, then that's going to enable our company to solve important problems in a constructive way."This is about understanding really cool chemistry," he added, "and trying to do something good with it."
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Environment
| 2,021 |
January 25, 2021
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https://www.sciencedaily.com/releases/2021/01/210125094334.htm
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Litter provides habitat for diverse animal communities in rivers
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In a study of local rivers, experts at the University of Nottingham in the UK have discovered more invertebrates -- animals without a backbone, such as insects and snails -- living on litter than on rocks.
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In urban rivers where there are no better alternatives, litter provided the largest, most stable and complex habitat available for invertebrates to live on.The findings could have important implications for the management of urban rivers, including how river clean-up events are conducted.The research team, in the School of Geography, studied three local rivers; the River Leen, Black Brook, and Saffron Brook, in Leicestershire and Nottinghamshire by collecting samples of rocks and litter from the riverbeds to compare in their laboratory.The scientists found that the surfaces of the litter were inhabited by different and more diverse communities of invertebrates than those on rocks. Plastic, metal, fabric, and masonry samples consistently had the highest diversity, meanwhile, glass and rock samples were considerably less diverse than other material samples.They observed that flexible pieces of plastic, like plastic bags, were inhabited by the most diverse communities and speculated that the types of invertebrates they found on flexible plastic suggests it might mimic the structure of water plants.The study is the first of its kind to evaluate the role of litter as a riverine habitat and has been published in the journal Hazel Wilson, project lead in the School of Geography at the University of Nottingham, said: "Our research suggests that in terms of habitat, litter can actually benefit rivers which are otherwise lacking in habitat diversity. A diverse community of invertebrates is important because they underpin river ecosystems by providing food for fish and birds, and by contributing to carbon/nutrient cycling.""However, this does not justify people littering. We absolutely should be working towards removing and reducing the amount of litter in freshwaters -- for many reasons, including the release of toxic chemicals and microplastics, and the danger of animals ingesting or becoming entangled with litter. Our results suggest that litter clearance should be combined with the introduction of complex habitat, such as tree branches or plants to replace that removed during litter picks."The authors say that their findings highlight the poor environmental quality in many urban rivers, given that the most complex habitat left for invertebrates is litter. They hope to build on this research by investigating which characteristics of litter enable it to support greater biodiversity, and how it compares to complex natural habitats, like water plants or pieces of wood.Hazel Wilson added: "This could help us discover methods and materials to replace the litter habitat with alternative and less damaging materials when we conduct river clean-ups."
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Environment
| 2,021 |
January 22, 2021
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https://www.sciencedaily.com/releases/2021/01/210122102022.htm
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Highly functional membrane developed for producing freshwater from seawater
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Professor MATSUYAMA Hideto's research group at Kobe University's Research Center for Membrane and Film Technology has successfully developed a new desalination membrane. They achieved this by laminating a two-dimensional carbon material
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Desalination In this research study, graphene oxide These research results were published in Main points97.5% of the water on Earth is seawater and only 2.5% is freshwater. Within this percentage, a mere 0.01% of freshwater resources can be easily treated in order to be utilized by humankind. However, the human population continues to increase every year. Consequently, it has been predicted that in several years' time, two thirds of the world's population will have insufficient access to freshwater. A worldwide water shortage is one of the gravest issues facing humankind. Therefore, technologies that can obtain the necessary resources by converting the Earth's abundant seawater into freshwater are paramount.Evaporation methods have been used to convert seawater to freshwater, however they require large amounts of energy in order to evaporate the seawater and remove the salt (desalination). On the other hand, membrane separation methods provide a low energy alternative; they enable freshwater to be produced by filtering water out of seawater and removing the salt. Methods of producing freshwater from seawater using membranes have been implemented, however with the desalination membranes developed so far there is always a trade-off between permeation speed and desalination ability. Therefore, it is vital to develop a revolutionary desalination membrane from new materials in order to resolve this trade-off and to make it possible to desalinate seawater at a higher rate of efficiency.This research team developed a highly functional desalination membrane by laminating the membrane with a two-dimensional carbon material of the approximate thickness of a carbon atom. These 2D carbon materials were graphene oxide nanosheets that were chemically reduced to give them strengthened π-π interaction.By applying nanosheet coatings with intercalation of porphyrin-based planar molecules (with charged groups and a conjugated π system) to the surface of a porous membrane, the research group was able to construct an ultrathin desalination membrane layer approximately 50nm thick.This layer demonstrated high ion-blocking functionality because the size of the nanochannels (the gaps between each nanosheet) could be controlled within 1nm. Furthermore, the gaps between the nanochannels in the nanosheet-laminated membrane demonstrated continuous water-stability due to the strong π-π stacking between the sheets, suggesting the possibility that it could be utilized for a long period of time. In addition, there was no loss of desalination functionality even under a pressure of 20 bar.The researchers revealed that the transfer of ions inside the developed nanosheet-laminated membrane were effectively suppressed by electrostatic repulsion on the nanosheet surface. This electrostatic repulsion was highly effective when the width of the nanochannels was appropriately controlled. For the nanosheet material used in this study, the width of the nanochannels could be confined by controlling the chemical reduction process and the intercalation ratio of porphyrin-based planar molecules.NaCl is the main component of seawater ions and it is particularly difficult to prevent it from permeating the membrane. However, a nanosheet-laminated membrane produced under optimal conditions was able to block around 95% of NaCl.The 2D nanosheet-laminated membrane developed through this research was produced by regulating the reduction of the oxidized graphene sheet and the intercalation ratio of planar molecules, which in turn enabled both the interlayer space between the nanosheets and the electrostatic repulsion effect to be controlled. In addition to desalination membranes, this technique can also be applied to the development of various electrolyte separation membranes.Low-energy desalination technologies using separation membranes are indispensable for reducing water shortages. It is hoped that the technology will contribute towards resolving the issue of water resources drying up worldwide. Next, the research team will try to further improve the developed membrane's high functionality, so that it can be implemented.
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Environment
| 2,021 |
January 22, 2021
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https://www.sciencedaily.com/releases/2021/01/210122085025.htm
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Forecasting coastal water quality
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Less than two days of water quality sampling at local beaches may be all that's needed to reduce illnesses among millions of beachgoers every year due to contaminated water, according to new Stanford research. The study, published in
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"This work combines knowledge of microbiology, coastal processes and data science to produce a tool to effectively manage one of our most precious resources and protect human health," said senior author Alexandria Boehm, a Stanford professor of civil and environmental engineering.Measuring concentrations of fecal indicator bacteria (FIB) -- which denote the presence of fecal matter and can lead to unsafe water conditions -- at beaches ensures the health and safety of the public. While all ocean water contains some degree of pathogens, such as bacteria or viruses, they're typically diluted to harmless concentrations. However, changes in rainfall, water temperature, wind, runoff, boating waste, storm sewer overflow, proximity to waste treatment plants, animals and waterfowl can lead to an influx of water contamination. Exposure to these contaminants can cause many ailments, including respiratory diseases and gastrointestinal illnesses, along with skin, eye and ear infections to swimmers.Protecting coastal waters and the people that use them remains essential for much of California's 840 miles of coastline. Over 150 million people swim, surf, dive and play at one of the state's 450 beaches annually, generating over $10 billion in revenue. According to the California State Water Resources Control Board, health agencies across 17 counties, publicly owned sewage treatment plants, environmental groups and several citizen-science groups perform water sampling across the state. However, not all waters are routinely checked due to accessibility issues, budget resource constraints or the season, despite their use by the public.Another obstacle to safeguarding public health lies in the lag time between sampling and results -- up to two-days -- leading beach managers to make decisions reflecting past water quality conditions. When monitored waters contain high levels of bacteria and pose a health risk, beach managers post warning signs or close beaches. The delay in current testing methods could unknowingly expose swimmers to unhealthy waters.To overcome these limitations, the researchers combined water sampling and environmental data with machine learning methods to accurately forecast water quality. While predictive water quality models aren't new, they have generally required historical data spanning several years to be developed.The team used water samples collected at 10-minute intervals over a relatively brief timeframe of one to two days at beaches in Santa Cruz, Monterey and Huntington Beach. Among the three sites, 244 samples were measured for FIB concentrations and marked as above or below the acceptable level deemed safe by the state. The researchers then collected meteorological data such as air temperature, solar radiation and wind speed along with oceanographic data including tide level, wave heights and water temperature (all factors influencing FIB concentrations) over the same timeframe.Using the high-frequency water quality data and machine learning methods, they trained computer models to accurately predict FIB concentrations at all three beaches. The researchers found hourly water sampling for 24 hours straight -- capturing an entire tidal and solar cycle -- proved enough for reliable results. Feeding the framework meteorological and tidal data from longer time periods resulted in future water quality predictions that were dependable for at least an entire season."These results are really empowering for communities who want to know what's going on with water quality at their beach," Searcy said. "With some resources to get started and a day of sampling, these communities could collect the data needed to initiate their own water quality modeling systems."The framework code, which is publicly accessible, could also be developed for accurate predictions of other contaminants such as harmful algae, metals and nutrients known to wreak havoc on local waters. The researchers point out that more analysis is needed to better determine the exact timeframe these models remain accurate and note that continually assessing and retraining the models remains a best practice for accurate predictions.
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Environment
| 2,021 |
January 21, 2021
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https://www.sciencedaily.com/releases/2021/01/210121151000.htm
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Squeezing a rock-star material could make it stable enough for solar cells
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Among the materials known as perovskites, one of the most exciting is a material that can convert sunlight to electricity as efficiently as today's commercial silicon solar cells and has the potential for being much cheaper and easier to manufacture.
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There's just one problem: Of the four possible atomic configurations, or phases, this material can take, three are efficient but unstable at room temperature and in ordinary environments, and they quickly revert to the fourth phase, which is completely useless for solar applications.Now scientists at Stanford University and the Department of Energy's SLAC National Accelerator Laboratory have found a novel solution: Simply place the useless version of the material in a diamond anvil cell and squeeze it at high temperature. This treatment nudges its atomic structure into an efficient configuration and keeps it that way, even at room temperature and in relatively moist air.The researchers described their results in "This is the first study to use pressure to control this stability, and it really opens up a lot of possibilities," said Yu Lin, a SLAC staff scientist and investigator with the Stanford Institute for Materials and Energy Sciences (SIMES)."Now that we've found this optimal way to prepare the material," she said, "there's potential for scaling it up for industrial production, and for using this same approach to manipulate other perovskite phases."Perovskites get their name from a natural mineral with the same atomic structure. In this case the scientists studied a lead halide perovskite that's a combination of iodine, lead and cesium.One phase of this material, known as the yellow phase, does not have a true perovskite structure and can't be used in solar cells. However, scientists discovered a while back that if you process it in certain ways, it changes to a black perovskite phase that's extremely efficient at converting sunlight to electricity. "This has made it highly sought after and the focus of a lot of research," said Stanford Professor and study co-author Wendy Mao.Unfortunately, these black phases are also structurally unstable and tend to quickly slump back into the useless configuration. Plus, they only operate with high efficiency at high temperatures, Mao said, and researchers will have to overcome both of those problems before they can be used in practical devices.There had been previous attempts to stabilize the black phases with chemistry, strain or temperature, but only in a moisture-free environment that doesn't reflect the real-world conditions that solar cells operate in. This study combined both pressure and temperature in a more realistic working environment.Working with colleagues in the Stanford research groups of Mao and Professor Hemamala Karunadasa, Lin and postdoctoral researcher Feng Ke designed a setup where yellow phase crystals were squeezed between the tips of diamonds in what's known as a diamond anvil cell. With the pressure still on, the crystals were heated to 450 degrees Celsius and then cooled down.Under the right combination of pressure and temperature, the crystals turned from yellow to black and stayed in the black phase after the pressure was released, the scientists said. They were resistant to deterioration from moist air and remained stable and efficient at room temperature for 10 to 30 days or more.Examination with X-rays and other techniques confirmed the shift in the material's crystal structure, and calculations by SIMES theorists Chunjing Jia and Thomas Devereaux provided insight into how the pressure changed the structure and preserved the black phase.The pressure needed to turn the crystals black and keep them that way was roughly 1,000 to 6,000 times atmospheric pressure, Lin said - about a tenth of the pressures routinely used in the synthetic diamond industry. So one of the goals for further research will be to transfer what the researchers have learned from their diamond anvil cell experiments to industry and scale up the process to bring it within the realm of manufacturing.
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Environment
| 2,021 |
January 21, 2021
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https://www.sciencedaily.com/releases/2021/01/210121150931.htm
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Researchers prove fish-friendly detection method more sensitive than electrofishing
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Delivering a minor electric shock into a stream to reveal any fish lurking nearby may be the gold standard for detecting fish populations, but it's not much fun for the trout.
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Scientists at Oregon State University have found that sampling stream water for evidence of the presence of various species using environmental DNA, known as eDNA, can be more accurate than electrofishing, without disrupting the fish."It's revolutionizing the way we do fish ecology work," said Brooke Penaluna, a research fish biologist with the U.S. Department of Agriculture Forest Service who also has an appointment in OSU's Department of Fisheries and Wildlife. "You can identify species from a bottle of water using genetic tools. When you go out to the site, I can tell you what's in that stream just based on what's in this bottle of water."Penaluna is lead author on a study published Wednesday in Determining how far upstream fish are present is crucial for guiding forest management practices, as streams with fish in them receive more protections than streams without fish. It also helps inform conservation by improving scientists' understanding of specific species' distribution and movements.Electrofishing has been the standard method for surveying fish distribution in bodies of water since the 1960s. It involves sticking two electrodes into the water and applying direct current, which affects fish swimming nearby and causes them to swim toward one of the electrodes. The person doing the sampling can then scoop up the dazed fish in a net and collect data before returning them to the water, where they resume normal activity within a few minutes.Research sampling for eDNA has been used for over a decade but is not widely used yet in industry or resource management. It involves collecting water samples on-site and running lab tests to check for the presence of DNA for certain species of fish, which the fish shed regularly through excretion and changes in their skin or mucus.The OSU study tested the effectiveness of eDNA in finding the "last fish" point, the farthest upstream fish are present. The researchers looked for coastal cutthroat trout as they are the fish most commonly found the highest upstream in streams on the west side of the Pacific Northwest, due to their life cycle and size.Researchers chose 60 coastal streams in Oregon and Washington and conducted eDNA sampling and electro-fishing every 50 meters up to 250 meters upstream of the last recorded "last fish" point for each stream.They found that in streams where electrofishing detected no trout, there was still a 40% chance that eDNA sampling would show evidence of their presence. eDNA detection revealed fish higher upstream than electrofishing did in 31 streams, in some cases up to 250 meters above where electrofishing pinpointed the "last fish."However, both methods still struggled to detect trout when the fish were in low density.The researchers determined that eDNA is a useful complement to electrofishing, especially in places where debris or vegetation make electrofishing impractical, but it's not a full replacement. eDNA detection is less disruptive to fish and requires fewer permits for researchers, but electrofishing provides researchers the opportunity to record other physical data about the fish, including size, health and appearance, that eDNA detection does not allow."We're trying to make the point that we're not aiming to eliminate electrofishing; just that we can use this as a complement to that, to provide more information quickly and cleanly," said Ivan Arismendi, co-author on the study and an assistant professor in OSU's Department of Fisheries and Wildlife."You can use one and the other like a confirmatory tool -- so if you have a question about endangered species, you can use both, and you can be more robust about the presence if both methods agree."The researchers hope eDNA detection becomes more popular, as the cost and time required to run eDNA tests continues to fall and field-based equipment is becoming more readily available. eDNA detection in a nearby stream would even be possible to use for a school project, Penaluna said."I think there's really broad use for this," she said. "Now I think the next steps are for managers and policymakers to start drawing some of those guidelines."The study was an example of co-production science where federal, state and private landowners worked with researchers. Penaluna collaborated with OSU researchers Arismendi, Jennifer Allen, Taal Levi and Tiffany Garcia; and Jason Walter of the Weyerhaeuser Centralia Research Center in Washington.
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Environment
| 2,021 |
January 21, 2021
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https://www.sciencedaily.com/releases/2021/01/210121131752.htm
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Producing green hydrogen through the exposure of nanomaterials to sunlight
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A research team from the Institut national de la recherche scientifique (INRS) has joined forces with French researchers from the Institute of Chemistry and Processes for Energy, Environment and Health (ICPEES), a CNRS-University of Strasbourg joint research lab, to pave the way towards the production of green hydrogen. This international team has developed new sunlight-photosensitive-nanostructured electrodes. The results of their research were published in the November 2020 issue of the journal of Solar Energy Materials and Solar Cells.
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Hydrogen is being considered by several countries of the Organisation for Economic Co-operation and Development (OECD) as a key player in the transition towards decarbonized industries and sectors. According to the INRS Professor My Ali El Khakani, Quebec could strategically position itself in this energy sector of the future. "Thanks to high-performance nanomaterials, we can improve the efficiency of water dissociation to produce hydrogen. This "clean" fuel is becoming increasingly important for the decarbonisation of the heavy-duty trucking and public transportation. For example, buses using hydrogen as a fuel are already in operation in several European countries and in China. These buses emit water instead of greenhouse gases," added the physicist and nanomaterials specialist.Splitting water molecules into oxygen and hydrogen has long been done by electrolysis. However, industrial electrolyzers are very energy-intensive and require large investments. The INRS and ICPEES researchers were rather inspired by a natural mechanism: photosynthesis. Indeed, they have developed specially engineered and structured electrodes that split water molecules under the sun's light. This is a process known as photocatalysis.For maximum use of solar energy, the research teams have selected a very abundant and chemically stable material: titanium dioxide (TiOThe researchers have then proceeded with the nanostructuration of the electrode to form a network of TiOThe final step of the electrode elaboration is their "nanodecoration." This process consists of depositing catalyst nanoparticles on the otherwise infinite network of TiOThis research identified cobalt oxide (CoO), a material that is quite available in Quebec's underground, as effective co-catalysts for splitting water molecules. A comparison of the two materials showed that CoO nanoparticles enabled a tenfold increase the photocatalytic efficiency of these new nanodecorated electrodes under visible light compared to bare nanotubes.
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Environment
| 2,021 |
January 21, 2021
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https://www.sciencedaily.com/releases/2021/01/210121131701.htm
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Turbulence model could help design aircraft capable of handling extreme scenarios
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In 2018, passengers onboard a flight to Australia experienced a terrifying 10-second nosedive when a vortex trailing their plane crossed into the wake of another flight. The collision of these vortices, the airline suspected, created violent turbulence that led to a free fall.
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To help design aircraft that can better maneuver in extreme situations, Purdue University researchers have developed a modeling approach that simulates the entire process of a vortex collision at a reduced computational time. This physics knowledge could then be incorporated into engineering design codes so that the aircraft responds appropriately.The simulations that aircraft designers currently use capture only a portion of vortex collision events and require extensive data processing on a supercomputer. Not being able to easily simulate everything that happens when vortices collide has limited aircraft designs.With more realistic and complete simulations, engineers could design aircraft such as fighter jets capable of more abrupt maneuvers or helicopters that can land more safely on aircraft carriers, the researchers said."Aircraft in extreme conditions cannot rely on simple modeling," said Carlo Scalo, a Purdue associate professor of mechanical engineering with a courtesy appointment in aeronautics and astronautics."Just to troubleshoot some of these calculations can take running them on a thousand processors for a month. You need faster computation to do aircraft design."Engineers would still need a supercomputer to run the model that Scalo's team developed, but they would be able to simulate a vortex collision in about a tenth to a hundredth of the time using far less computational resources than those typically required for large-scale calculations.The researchers call the model a "Coherent-vorticity-Preserving (CvP) Large-Eddy Simulation (LES)." The four-year development of this model is summarized in a paper published in the "The CvP-LES model is capable of capturing super complex physics without having to wait a month on a supercomputer because it already incorporates knowledge of the physics that extreme-scale computations would have to meticulously reproduce," Scalo said.Former Purdue postdoctoral researcher Jean-Baptiste Chapelier led the two-year process of building the model. Xinran Zhao, another Purdue postdoctoral researcher on the project, conducted complex, large-scale computations to prove that the model is accurate. These computations allowed the researchers to create a more detailed representation of the problem, using more than a billion points. For comparison, a 4K ultra high definition TV uses approximately 8 million points to display an image.Building off of this groundwork, the researchers applied the CvP-LES model to the collision events of two vortex tubes called trefoil knotted vortices that are known to trail the wings of a plane and "dance" when they reconnect.This dance is extremely difficult to capture."When vortices collide, there's a clash that creates a lot of turbulence. It's very hard computationally to simulate because you have an intense localized event that happens between two structures that look pretty innocent and uneventful until they collide," Scalo said.Using the Brown supercomputer at Purdue for mid-size computations and Department of Defense facilities for large-scale computations, the team processed data on the thousands of events that take place when these vortices dance and built that physics knowledge into the model. They then used their turbulence model to simulate the entire collision dance.Engineers could simply run the ready-made model to simulate vortices over any length of time to best resemble what happens around an aircraft, Scalo said. Physicists could also shrink the model down for fluid dynamics experiments."The thing that's really clever about Dr. Scalo's approach is that it uses information about the flow physics to decide the best tactic for computing the flow physics," said Matthew Munson, program manager for Fluid Dynamics at the Army Research Office, an element of the U.S. Army Combat Capabilities Development Command's Army Research Laboratory."It's a smart strategy because it makes the solution method applicable to a wider variety of regimes than many other approaches. There is enormous potential for this to have a real impact on the design of vehicle platforms and weapons systems that will allow our soldiers to successfully accomplish their missions."Scalo's team will use Purdue's newest community cluster supercomputer, Bell, to continue its investigation of complex vortical flows. The team also is working with the Department of Defense to apply the CvP-LES model to large-scale test cases pertaining to rotorcrafts such as helicopters."If you're able to accurately simulate the thousands of events in flow like those coming from a helicopter blade, you could engineer much more complex systems," Scalo said.This work was supported by the Army Research Office's Young Investigator Program under award W911NF-18-1-0045. The researchers also acknowledge the support of the Rosen Center for Advanced Computing at Purdue, and the U.S. Air Force Research Laboratory Department of Defense Supercomputing Resource Center, via allocation under the subproject ARONC00723015.
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Environment
| 2,021 |
January 21, 2021
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https://www.sciencedaily.com/releases/2021/01/210121131652.htm
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Seeds transfer their microbes to the next generation
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Scientists have been pondering if the microbiome of plants is due to nature or nurture. Research at Stockholm University, published in
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"The idea that seeds can be the link between the microbes in the mother tree and its offspring has frequently been discussed, but this is the first time someone proves the transmission route from the seed to the leaves and roots of emerging plants," says Ahmed Abdelfattah, researcher at the Department of Ecology Environment and Plant Sciences (DEEP) at Stockholm University.The microorganisms found on the seed are often valuable for the plant, promoting its growth and protecting it against certain diseases. Each plant species harbours a distinct microbial community, with some of the microbes living on its surface and others inside the plant's tissues.The finding also means that since the microorganisms from the seed are there first, they can constitute a barrier which influences subsequent colonization by other microbes from the environment. The experiment was done in oaks, since it's one of the most abundant tree species in the Swedish and European forests."The microorganisms from the seed are also expected to be very important for plant health and functioning," says Ahmed Abdelfattah.The fossil record indicates that plants have been associated with fungi and bacteria -- constituting the microbiome -- for more than 400 million years. Several species the scientists found on the oak seeds are already shown by other studies to be involved in the protection against several plant pathogens, growth-promotion, nitrogen-fixing, and the detoxification or biodegradation of toxic environmental pollutants.Demonstrating inheritance under natural conditions is challenging since seeds are exposed to and dependent on their surrounding environment when they sprout, especially the soil, which is a microbially rich environment. Therefore, it's nearly impossible to differentiate between which microorganism actually come from the seed or from the soil. The research team therefore used a novel culturing device, to grow oak seedlings in a microbe-free condition and keep the leaves separated from the roots. This allowed them to be certain that the microorganisms came from the seed, and that they could demonstrate that some seed microorganisms migrate to the roots, and some others to the leaves."Plant leaves and roots are already known to harbor distinct microbial communities, as shown by several recent studies. In this study however, we were surprised to see that it is also true at an early stage of the plant development, and that the seed could, at least partially, be responsible for these differences," Says Ahmed Abdelfattah"Several breeding companies are taking into consideration the seed microbiome in their programs hoping to have super plants with better genes and better microbes. One technique used, is to treat seeds with beneficial microorganism with the aim that those microbes will eventually colonize the plant and exert their effects throughout the plant's life," says Ahmed Abdelfattah.The next step for the research team is now to discern which is the major source of the of the microbiome -- the environment or the seed.
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Environment
| 2,021 |
January 21, 2021
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https://www.sciencedaily.com/releases/2021/01/210121131901.htm
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Indigenous lands: A haven for wildlife
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Indigenous peoples' lands may harbour a significant proportion of threatened and endangered species globally, according to University of Queensland-led research.
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UQ's Dr Chris O'Bryan and his team conducted the first comprehensive analysis of land mammal composition across mapped Indigenous lands."These lands cover more than one-quarter of the Earth, of which a significant proportion is still free from industrial-level human impacts," Dr O'Bryan said."As a result, Indigenous peoples and their lands are crucial for the long-term persistence of the planet's biodiversity and ecosystem services."Despite this, we know relatively little about what animals, including highly imperilled species, may reside in or depend on these lands."The team overlayed maps of Indigenous peoples' lands and habitat data for 4,460 species assessed by the International Union for Conservation of Nature (IUCN) to estimate the overlap of each species."We picked mammals as a bellwether indicator of biodiversity protection," Dr O'Bryan said."This is because there's more data about the suitable habitat of mammals and there is evidence to suggest that patterns observed in mammals may reflect other forms of biodiversity."In other words, if mammals are absent, other animals are likely to be absent as well."We're hoping this study provides future opportunities for applying our methodology to other animal groups."We discovered that 2,175 mammal species -- about half of the total species tracked -- have at least 10 per cent of their ranges in Indigenous peoples' lands."And 646 species -- or 14 per cent -- have more than half of their ranges within these lands."Amazingly, for threatened species in particular, 413 -- or about 41 per cent of threatened species tracked -- occur in Indigenous peoples' lands."The endangered red panda (Ailurus fulgens) and the tiger (Panthera tigris) of Southeast Asia have more than half their habitat within such lands."In Australia, the critically endangered northern hairy-nosed wombat (Lasiorhinus krefftii) has 100 per cent of its habitat in these lands."Dr O'Bryan said the work showed the importance of Indigenous peoples' lands."These areas are critical for the successful implementation of international conservation and sustainable development agendas," he said."Representatives of Indigenous peoples are engaging in global environmental forums and national and local collaboration frameworks, which are critical for equitable and effective cross-cultural conservation activities to be negotiated."Greater recognition and support for Indigenous people's rights to, and relationships with, their lands needs to continue, and this pressing imperative needs to balance Indigenous self-determination and biodiversity conservation."Only through rights-based, equitable and respectful partnerships with Indigenous peoples, will it be possible to ensure the long-term and equitable conservation of biodiversity."
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Environment
| 2,021 |
January 20, 2021
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https://www.sciencedaily.com/releases/2021/01/210120085052.htm
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An anode-free zinc battery that could someday store renewable energy
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Renewable energy sources, such as wind and solar power, could help decrease the world's reliance on fossil fuels. But first, power companies need a safe, cost-effective way to store the energy for later use. Massive lithium-ion batteries can do the job, but they suffer from safety issues and limited lithium availability. Now, researchers reporting in ACS'
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Aqueous zinc-based batteries have been previously explored for grid-scale energy storage because of their safety and high energy density. In addition, the materials used to make them are naturally abundant. However, the rechargeable zinc batteries developed so far have required thick zinc metal anodes, which contain a large excess of zinc that increases cost. Also, the anodes are prone to forming dendrites -- crystalline projections of zinc metal that deposit on the anode during charging -- that can short-circuit the battery. Yunpei Zhu, Yi Cui and Husam Alshareef wondered whether a zinc anode was truly needed. Drawing inspiration from previous explorations of "anode-free" lithium and sodium-metal batteries, the researchers decided to make a battery in which a zinc-rich cathode is the sole source for zinc plating onto a copper current collector.In their battery, the researchers used a manganese dioxide cathode that they pre-intercalated with zinc ions, an aqueous zinc trifluoromethanesulfonate electrolyte solution and a copper foil current collector. During charging, zinc metal gets plated onto the copper foil, and during discharging the metal is stripped off, releasing electrons that power the battery. To prevent dendrites from forming, the researchers coated the copper current collector with a layer of carbon nanodiscs. This layer promoted uniform zinc plating, thereby preventing dendrites, and increased the efficiency of zinc plating and stripping. The battery showed high efficiency, energy density and stability, retaining 62.8% of its storage capacity after 80 charging and discharging cycles. The anode-free battery design opens new directions for using aqueous zinc-based batteries in energy storage systems, the researchers say.
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Environment
| 2,021 |
January 20, 2021
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https://www.sciencedaily.com/releases/2021/01/210120085049.htm
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Study shows how network of marine protected areas could help safeguard Antarctic penguins
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New research led by BirdLife International, the University of East Anglia (UEA) and British Antarctic Survey highlights how a proposed network of marine protected areas could help safeguard some of the most important areas at sea for breeding Antarctic penguins.
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The findings, published today in the journal The Southern Ocean surrounding Antarctica is home to thousands of unique species, including seals, whales and four species of penguins -- the Adélie, Chinstrap, Gentoo and Emperor. Many of these feed on krill, tiny shrimp-like crustaceans, which are also the target of large commercial fisheries, who harvest them for a variety of krill-based products including fish food.Penguins are often considered an indicator species whose populations reflect the state of the surrounding marine environment. However, many vital penguin habitats remain unprotected, leaving them susceptible to human-related threats such as pollution, overfishing and climate change.The study used a new approach based on colony location, population estimates, and tracking data, to identify globally important areas for penguin species around Antarctica, pinpointing 63 key sites.Known as Important Bird and Biodiversity Areas (IBAs), they are used by at least 1% of a species' global population. They represent important foraging grounds, surrounding breeding colonies of several thousands of individuals when penguins congregate to raise their chicks.The international team also examined krill fishery activities over the last 50 years and found that while its range of operation has contracted, a consistently disproportionate amount of krill is being harvested within the globally important areas for penguins compared to the total area in which the fishery operates. The results align with other studies which show that krill fisheries might be directly competing with penguins for crucial foraging resources."Our findings provide critical evidence about the location and relevance of some of the most important areas globally for chick-rearing adult penguins breeding in Antarctica and nearby islands," said lead author Dr Jonathan Handley, of Birdlife International."Over the past five decades, krill fisheries have concentrated into a small number of areas in Antarctic waters, some of which we identified as important penguin foraging grounds. This poses a likely threat for several penguin colonies, especially when they are rearing chicks."To control the increasing commercial interest in Antarctic fisheries and particularly krill resources, an international convention was established in 1982, governed by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) -- an international convention comprised of 25 Member states, together with the European Union.The convention envisioned the creation of a network of MPAs around Antarctica since 2002, but since 2016 only two have been implemented. Three more have been under discussion for several years but members have not been able to agree on their formal designation.Co-author Dr Aldina Franco, of UEA's School of Environmental Sciences, said the new study supports the adoption of the proposed MPA network: "Recent studies have shown that krill fisheries could be directly competing with penguins for critical food supplies. The proposed Marine Protected Area network, which has recognised go/no go areas for krill fisheries, can help guarantee that enough krill is available for penguins."Marie-Morgane Rouyer, who jointly led the research while a Masters student at UEA, added: "Marine resources need to be managed in a sustainable way if we are to guarantee the existence of these emblematic penguin species in the future."The researchers identified new IBAs that are important for the conservation of Antarctic penguins and examined the overlap with existing and proposed MPAs. They found that Adélie and Emperor penguins currently have 27-31% of the important areas within adopted MPAs, but no Gentoo's IBAs and only 1% of Chinstrap's are within them.If all proposed MPAs for Antarctica are adopted then an average of 80% of the important areas for penguin conservation would be within an MPA. This highlights the importance of the proposed network, which ultimately could benefit not only Antarctic penguins, but some of the most unique wildlife on Earth.The research was funded by the Pew Charitable Trusts.
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Environment
| 2,021 |
January 20, 2021
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https://www.sciencedaily.com/releases/2021/01/210119194403.htm
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Free online tool calculates risk of COVID-19 transmission in poorly-ventilated spaces
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The vital role of ventilation in the spread of COVID-19 has been quantified by researchers, who have found that in poorly-ventilated spaces, the virus spreads further than two metres in seconds, and is far more likely to spread through prolonged talking than through coughing.
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The results, reported in the journal The researchers, from the University of Cambridge and Imperial College London, used mathematical models to show how SARS-CoV-2 -- the virus which causes COVID-19 -- spreads in different indoor spaces, depending on the size, occupancy, ventilation and whether masks are being worn. These models are also the basis of a free online tool, The researchers found that when two people are in a poorly-ventilated space and neither is wearing a mask, prolonged talking is far more likely to spread the virus than a short cough. When speaking, we exhale smaller droplets, or aerosols, which spread easily around a room, and accumulate if ventilation is not adequate. In contrast, coughing expels more large droplets, which are more likely to settle on surfaces after they are emitted.It only takes a matter of seconds for aerosols to spread over two metres when masks are not worn, implying that physical distancing in the absence of ventilation is not sufficient to provide safety for long exposure times. When masks of any kind are worn however, they slow the breath's momentum and filter a portion of the exhaled droplets, in turn reducing the amount of virus in aerosols that can spread through the space.The scientific consensus is that the vast majority of COVID-19 cases are spread through indoor transmission -- whether via aerosols or droplets. And as was predicted in the summer and autumn, now that winter has arrived in the northern hemisphere and people are spending more time indoors, there has been a corresponding rise in the number of COVID-19 cases."Our knowledge of airborne transmission of SARS-CoV-2 has evolved at an incredible pace, when you consider that it's been just a year since the virus was identified," said Dr Pedro de Oliveira from Cambridge's Department of Engineering, and the paper's first author. "There are different ways to approach this problem. In our work, we consider the wide range of respiratory droplets humans exhale to demonstrate different scenarios of airborne viral transmission -- the first being the quick spread of small infectious droplets over several metres in a matter of a few seconds, which can happen both indoors and outdoors. Then, we show how these small droplets can accumulate in indoor spaces in the long term, and how this can be mitigated with adequate ventilation."The researchers used mathematical models to calculate the amount of virus contained in exhaled particles, and to determine how these evaporate and settle on surfaces. In addition, they used characteristics of the virus, such as its decay rate and viral load in infected individuals, to estimate the risk of transmission in an indoor setting due to normal speech or a short cough by an infectious person. For instance, they show that the infection risk after speaking for one hour in a typical lecture room was high, but the risk could be decreased significantly with adequate ventilation.Based on their models, the researchers have now built Airborne.cam, a free, open-source tool which can be used by those managing public spaces, such as shops, workplaces and classrooms, in order to determine whether ventilation is adequate. The tool is already in use in several academic departments at the University of Cambridge. The tool is now a requirement for any higher-risk spaces at the University, enabling departments to easily identify hazards and control-measure changes needed to ensure aerosols are not allowed to become a risk to health."The tool can help people use fluid mechanics to make better choices, and adapt their day-to-day activities and surroundings in order to suppress risk, both for themselves and for others," said co-author Savvas Gkantonas, who led the development of the app with Dr de Oliveira."We're looking at all sides of aerosol and droplet transmission to understand, for example, the fluid mechanics involved in coughing and speaking," said senior author Professor Epaminondas Mastorakos, also from the Department of Engineering. "The role of turbulence and how it affects which droplets settle by gravity and which remain afloat in the air is, in particular, not well understood. We hope these and other new results will be implemented as safety factors in the app as we continue to investigate."The continuing development of Airborne.cam, which will soon be available for mobile platforms, is supported in part by Cambridge Enterprise and Churchill College.
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Environment
| 2,021 |
January 19, 2021
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https://www.sciencedaily.com/releases/2021/01/210119194345.htm
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Land deals meant to improve food security may have hurt
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Large-scale land acquisitions by foreign investors, intended to improve global food security, had little to no benefit, increasing crop production in some areas while simultaneously threatening local food security in others, according to researchers who studied their effects.
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The study, published in the "These land deals have been happening for the last two decades on a massive scale," said Marc Muller, assistant professor in the Department of Civil and Environmental Engineering and Earth Sciences at Notre Dame and lead author of the study. "Our goal was to use empirical data to sort out whether or not large-scale land acquisitions have improved food security by using empirical data. But what we found was that there was either no impact or a negative impact. There was no positive impact."Following a global food crisis during the early 2000s, foreign investors purchased more than 220 million acres of land in middle-income and developing countries, according to the study's estimates, to increase crop production and contribute to the global food supply."In many countries throughout the world land is being commodified, so it is becoming easier to buy and sell land. Those, and rising food prices, were drivers for these companies," Muller said.There are two competing arguments when it comes to land acquisitions. Proponents view the multinational companies that purchased the land as better positioned to improve production and increase crop yields. But those who oppose argue that the acquisitions encroach on natural resources, lead to displacement of local farm workers and can have a negative impact on local residents -- including giving rise to livelihood losses, social instability and/or violence in those regions.While scientists have analyzed these types of acquisitions using modeling studies, and others have looked at specific situations as a result of the land deals through case studies, Muller said this is the first global analysis of this scale.Muller and his team analyzed land deals across Latin America, eastern Europe, Africa and Asia. By combining satellite imagery, researchers could see whether crop lands expanded and/or intensified. "We also used data from agriculture surveys to identify what types of crops had been planted in and around those lands prior to the acquisition compared to after, to account for potential transitions from local crops to export-bound crops, and crops that can also be used for biofuel," such as palm oil and sugar cane, Muller said.According to the study, trends differed depending on the region -- and in some cases the acquisitions had a negative effect on household diets.In Latin America and eastern Europe -- where countries are considered middle-income -- investors purchased land in intensified agricultural areas, where crops were already export-bound and local residents already consumed food from global markets. "So, in that sense, these land deals didn't really change much," said Muller. "They didn't increase crop production and they didn't cause more damage to local food insecurity than what was already taking place. In Africa and Asia, things looked very different."The research showed that those land acquisitions increased cropland, cultivating previously uncultivated land, and showed a clear transition from local staple crops such as tapioca to export-bound crops such as wheat and flex crops for potential use as biofuel."These crops are interesting for investors because if the price of food is low and the price of energy is high, you can then use the crops for energy," said Muller. "But these types of crops are not nutrient dense, so it's not great in terms of food security. As a matter of fact, the data from the household surveys we studied showed a consistent decrease in diet diversity after the deals took place."The study is the first in a series the research team will produce based on their analysis. Forthcoming studies will look at the impact of large-scale land acquisitions in relation to water, energy and environment.Muller is an affiliated member of Notre Dame's Environmental Change Initiative and a faculty fellow with the Kellogg Institute for International Studies.Co-authors of the study include Gopal Penny, also at Notre Dame; Meredith T. Niles at the University of Vermont; Vincent Ricciardi at the University of British Columbia; Davide Danilo Chiarelli and Maria Cristina Rulli at the Polytechnic University of Milan; Kyle Frankel Davis at the University of Delaware; Jampel Dell'Angelo at the University of Amsterdam; Paolo D'Odorico and Lorenzo Rosa at the University of California, Berkeley; and Nathan D. Mueller at Colorado State University.The National Science Foundation, the United States Agency for International Development and the Mava Foundation funded the study.
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Environment
| 2,021 |
January 19, 2021
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https://www.sciencedaily.com/releases/2021/01/210119194326.htm
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Constructing termite turrets without a blueprint
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Following a series of studies on termite mound physiology and morphogenesis over the past decade, researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences have now developed a mathematical model to help explain how termites construct their intricate mounds.
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The research is published in the "Termite mounds are amongst the greatest examples of animal architecture on our planet," said L. Mahadevan, the Lola England de Valpine Professor of Applied Mathematics, of Organismic and Evolutionary Biology, and of Physics and lead author of the study. "What are they for? How do they work? How are they built? These are the questions that have puzzled many scientists for a long time."In previous research, Mahadevan and his team showed that day-to-night temperature variations drive convective flow in the mound that not only ventilates the colony but also move pheromone-like cues around, which trigger building behavior in termites.Here, the team zoomed in further to understand how termites build the intricately connected floors in individual mounds without a plan or a planner. With experimentalists from the University of Toulouse, France led by Guy Theraulaz, the researchers mapped the interior structures of two nests using CT scans, and quantified the spacing and arrangement of floors and ramps. Adding to the complexity of the nests is the fact that not only do termites build simple ramps to connect floors but they also build spiral ramps, like the ramps in parking garages, to connect multiple floors.Using these visualizations and incorporating the previous findings on how factors such as daily temperature shifts and pheromone flows drive building, OEB graduate student Alexander Heyde and Mahadevan constructed a mathematical framework to explain the layout of the mound.Heyde and Mahadevan thought of each component of the mound -- the air, the mud and the termites -- as intermixed fluids that vary in space and time."We can think of the collection of hundreds of thousands of termites as a fluid that can sense its environment and act upon it," said Heyde. "Then you have a real fluid, air, transporting pheromones through that environment, which drives new behaviors. Finally, you have mud, which is moved around by the termites, changing the way in which the pheromones flow. Our mathematical framework provided us with clear predictions for the spacing between the layers, and showed the spontaneous formation of linear and helical ramps.""Here is an example where we see that the usual division between the study of nonliving matter and living matter breaks down," said Mahadevan. "The insects create a micro-environment, a niche, in response to pheromone concentrations. This change in the physical environment changes the flow of pheromones, which then changes the termite behaviors, linking physics and biology through a dynamic architecture that modulates and is modulated by behavior. "In addition to partially solving the mystery of how these mounds work and are built, the research may well have implications for swarm intelligence in a range of other systems and even understanding aspects of tissue morphogenesis.Video:
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Environment
| 2,021 |
January 19, 2021
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https://www.sciencedaily.com/releases/2021/01/210119140207.htm
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Disease threatens to decimate western bats
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A four-year study recently published in
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Since it was first detected in 2006, white-nose syndrome has killed millions of bats in eastern and central North America. The spread of the fungal pathogen that causes white-nose syndrome in hibernating bats has reached several western U.S. states, mostly likely through bat-to-bat spread, and is presently threatening western species.Bats with white-nose syndrome have fungus growing on their nose and wings, as the name implies, but the fungal infection also triggers a higher frequency of arousals from hibernation. Each arousal involves an increase in body temperature from as low as near freezing (when bats use torpor) to an active mammalian body temperature (~98The researchers' aim was to provide managers with information on which western bat species may suffer high mortality and extinction risk if infected with the disease. To do so they combined an unprecedented field data collection effort with a mechanistic model that explains how energy is consumed during hibernation and how the causal fungus impacts this energy consumption. By comparing their new knowledge of how long bats infected with white-nose syndrome could hibernate against the duration of winter that they would need to hibernate with the disease, the authors predicted survival outcomes for each species. If a bat did not have sufficient energy to live beyond the duration of winter the simulation recorded a mortality.Three years of intensive fieldwork resulted in 946 bat captures (all released after measuring). Bat energetic measurements paired with hibernaculum environmental data were gathered for nine species that were sampled at eight sites scattered throughout the West. The researchers then assessed how the arrival of white-nose syndrome might affect hibernation energy use, and subsequently each species' ability to survive hibernation with the disease. Combining data on the host, the environment they select for hibernation, and how the pathogen grows at different temperature and humidity conditions the authors simulated how many days infected populations could hibernate under field conditions.The study revealed there are white-nose syndrome threats to all the small Myotis species examined, including M. ciliolabrum (western small-footed bat), M. evotis (long-eared bat), M. lucifugus (little brown bat), M. thysanodes (fringed myotis), and M. volans (long-legged bat), as well as Perimyotis subflavus (tricolored bat). In comparison, larger species like M. velifer (cave bat), Corynorhinus townsendii (Townsend's big-eared bat) and Eptesicus fuscus (big brown bat) are predicted to be less impacted. Further analysis showed body mass (and relatedly body-fat as these attributes are correlated) as well as hibernaculum water vapor deficit (i.e. relative humidity) explained over half the variation observed in bat survival.Dr. Catherine Haase, now Assistant Professor of Biology at Austin Peay State University and the study's lead author said: "Our results indicate the need to take a holistic view on conservation, as it is not just one thing that determines survival from white-nose syndrome, but rather the combination of bat, environment, and disease variables."All of the western bat species studied were insectivores, meaning they prey on insects, including those that are pests to agricultural crops. In addition to providing valuable ecosystem services, they are incredibly fascinating species, from their ability to echolocate to their unique immune system.Dr. Sarah Olson, Wildlife Conservation Society Health Program co-author and project Principle Investigator said: "This study demonstrates the value of collecting baseline data to pre-emptively understand a threat posed by a wildlife disease, like white-nose syndrome, to western bats, so that more proactive conservation measures can be taken to protect these species. Here, an all hands on deck approach is needed. Western states can take steps now to put protections in place before anticipated severe declines are observed, like reducing habitat loss and restricting access to hibernacula, as well as investing in research and surveillance."
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Environment
| 2,021 |
January 19, 2021
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https://www.sciencedaily.com/releases/2021/01/210119114320.htm
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A sea of rubbish: Ocean floor landfills
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The Messina Strait, a submarine bridge separating the island of Sicily from the Italian Peninsula, is the area with the largest marine litter density worldwide -- more than a million objects per square kilometre in some parts, as reported in a new review paper published in the journal
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Led by the University of Barcelona, this paper gathers the results of the scientific meeting on macrolitter that took place in May 2018, promoted by the European Commission's Joint Research Centre (JRC) and the German Alfred Wegener Institute (AWI). A team of twenty-five scientists from across the world treated issues such as data needs, methodologies, harmonisation and needs for further development.The study provides a synthesis of current knowledge on human-sourced materials lying on the seafloor and goes through the methodologies to improve future studies, "highlighting the need to understand litter occurrence, distribution and quantities in order to provide insight for appropriate (policy) measures," notes Georg Hanke, who adds that "the paper also shows the need to employ new methodologies -- i.e. imaging approaches -- to cover areas that had not been considered previously, and provides tools to enable quantitative assessments such as those under the EU Marine Strategy Framework Directive (MSFD)."Among other signatories of the article are experts from the University of Açores (Portugal), Alfred Wegener Institute (Germany), Utrecht University (Netherlands), the Norwegian Institute of Marine Research (Norway), the Secretariat of the Barcelona Convention on the protection of the Mediterranean Sea, Monterey Bay Aquarium Research Institute (MBARI, California, United States), the Institute for Global Change of the Japan Agency for Marine Earth Science and Technology Research (JAMSTEC, Japan), IFREMER (France) and Oxford University (United Kingdom), among other institutions.The ocean floor is increasingly accumulating marine litter. Whereas the largest seafloor litter hotspots -- likely in the deep sea -- are still to be found, plastics have already been found in the deepest point on Earth, the Mariana Trench -- at a depth of 10,900 meters -- in the Pacific Ocean. In some cases, litter concentrations reach densities comparable to large landfills, experts warn.Despite the scientific community efforts, "the extent of marine litter on our seas and oceans is not yet fully known. The marine regions most affected by this problem are in landlocked and semi-enclosed seas, coastal bottoms, marine areas under the influence of large river mouths, and places with high fishing activity, even far from land," says Professor Miquel Canals, head of the Consolidated Research Group on Marine Geosciences at UB.Canals highlights that "the level of waste treatment in coastal countries is decisive: the less treatment -- or the more deficient -- the more waste reaching the ocean, and therefore, the ocean floor, which is a problem that affects specially third world countries."Plastics, fishing gears, metal, glass, ceramics, textiles and paper are the most abundant materials in seafloor litter hotspots. Geomorphological features, the submarine relief and the nature of the seafloor determine the distribution of litter items on the seabed. Ocean dynamics -- that is, processes such as dense water cascades, ocean currents and storms -- ease the transport and dispersal of litter across the ocean, from coasts to abyssal plains, thousands of meters deep. However, these factors do not occur in all ocean ecosystems and also vary over time and in intensity where they take place.Due to a gravitational effect, light waste is usually transported along and into marine regions where dense currents flow -- i.e. submarine canyons and other submarine valleys -- and where flow lines concentrate, such as nearby large submarine reliefs. Finally, materials transported by ocean dynamics accumulate in depressions and quiet marine areas.The properties of materials dumped in the marine environment also affect their dispersion and accumulation on the ocean floor. It is estimated that 62% of the dirt accumulated on seabeds is made of plastics, "which is relatively light and easy to transport over long distances. On the other hand, heavy objects such as barrels, cables or nets are usually left at the point where they are initially fell or got entangled," says Canals.Litter is a new threat to marine biodiversity. It is already known that nearly 700 marine species, 17% of which are on the IUCN red list, have been affected by this problem in several ways. Seabed entangled fishing gears can cause serious ecological impacts for decades because of ghost fishing. The slow decomposition of fishing nets -- usually made of high-strength polymers -- aggravates the detrimental effects of this type of waste on the marine ecosystem.Other human activities -- dredging, trawling, etc. -- trigger secondary dispersal by remobilization and fragmentation of seafloor litter. In addition, seabed waste concentrations can easily trap other objects, thus generating larger and larger litter accumulations. It is paradoxical that waste may increase the heterogeneity of the substrate, which can benefit some organisms. Some xenobiotic compounds -- pesticides, herbicides, pharmaceuticals, heavy metals, radioactive substances, etc. -- associated to litter are highly resistant to degradation and endanger marine life. However, the extent of the effects of litter on the habitats of the vast expanses of the deep ocean still is a chapter to be written by the scientific community."In the Mediterranean Sea," says Miquel Canals, "seafloor marine litter already is a serious ecological problem. In some places of the Catalan coast, there are large accumulations of waste. When there are strong storms, such as Gloria, in January 2020, waves throw this waste on the beach. Some beaches in the country were literally paved with rubbish, thus showing to which extent the coastal seabed is littered. There are also noticeable concentrations of waste in some submarine canyons outside Catalonia."Beach litter and floating garbage can be identified and monitored by simple, low-cost methods. In contrast, the study of seafloor litter is a technological challenge, the complexity of which increases with water depth and remoteness of the marine area to be investigated. The study reviews both methodologies allowing physical sampling of seafloor waste and New technologies have enabled major advances in the study of the environmental status of the seabed worldwide. The use of unmanned remotely operated vehicles (ROVs) is critical for Knowledge and data about seafloor litter are necessary for the implementation of the Marine Strategy Framework Directive (MSFD) and other international policy frameworks, including global agreements. The publication shows how research on seafloor macrolitter can inform these international protection and conservation frameworks to prioritize efforts and measures against marine litter and its deleterious impacts.The authors warn about the need to promote specific policies to minimize such a serious environmental problem. The study also addresses the debate on the removal of litter from the seabed, a management option that should be safe and efficient. In relation to this, the Joint Research Centre (JRC) is co-chairing the MSFD Technical Group on Marine Litter, which provides an information exchange and discussion platform to provide agreed guidance for MSFD implementation."Marine litter has reached the most remote places in the ocean, even the least (or never) frequented by our species and not yet mapped by science," says Miquel Canals. "In order to correct something bad, we must attack its cause. And the cause of the accumulation of waste on the coasts, seas and oceans, and all over the planet, is the excess waste generation and spillage in the environment, and poor or insufficient management practices. As humans, we have little or no care at all to prevent litter from accumulating everywhere."
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Environment
| 2,021 |
January 19, 2021
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https://www.sciencedaily.com/releases/2021/01/210119085230.htm
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Sequencing of wastewater useful for control of SARS-CoV-2
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Viral genome sequencing of wastewater can detect new SARS-CoV-2 variants before they are detected by local clinical sequencing, according to a new study reported in
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"SARS CoV-2 virus is excreted by individuals that are infected by COVID -19and the fecal waste ends up in the wastewater systems. By sampling wastewater, we can get information on infections for a whole population. Some wastewater systems serve several thousand people. Some serve hundreds of thousands of people," said principal study investigator Kara Nelson, PhD, professor of civil and environmental engineering, in the College of Engineering at the University of California-Berkeley. "Sampling wastewater is a very efficient way to get information. It is also a less biased source of information, because we can get information from all individuals in the sewershed, whether or not they are being tested in a clinic. We know that there are individuals that have asymptomatic infections that may never get tested."In the new study, researchers developed and used a novel method for sampling wastewater. When researchers sequence RNA concentrated and extracted from wastewater samples, there may be many different strains present because there are many individuals contributing to the sample. However, it is challenging to distinguish the SARS-CoV-2 genetic signal from the billions of bacteria and viruses people excrete every day. Researchers must identify SARS CoV-2 amidst a whole soup of other genomic material."The way that we need to process the sequence information is complex. One contribution of this paper is the ability to prepare samples for sequencing from wastewater. Instead of directly sequencing everything present, we used an enrichment approach where you first try to enrich the RNA that you are interested in," said Dr. Nelson. "Then we developed a novel bioinformatic analysis approach which was sensitive enough to detect a single nucleotide difference. You can't get any more sensitive than that."The researchers sequenced RNA directly from sewage collected by municipal utility districts in the San Francisco Bay Area to generate complete and nearly complete SARS-CoV-2 genomes. The researchers found that the major consensus SARS-CoV-2 genotypes detected in the sewage were identical to clinical genomes from the region. While the observed wastewater variants were more similar to local California patient-derived genotypes than they were to those from other regions, they also detected single nucleotide variants that had only been reported from elsewhere in the United States or globally. Thus, the researchers found that wastewater sequencing can provide evidence for recent introductions of viral lineages before they are detected by local clinical sequencing. By understanding which strains of SARS-CoV-2 are present in populations over time, researchers can gain insight into how transmission is occurring and whether new variants, like B.1.1.7, are dominating transmission."Of everyone who gets tested, only a fraction of those samples even get sequenced. When you are sampling the wastewater, you get a more comprehensive and less biased data on your population," said Dr. Nelson. "It appears that we might be able to get an earlier signal in the wastewater if a new variant shows up compared to only relying on the sequencing of clinical samples. Just knowing that SARS-CoV-2 is present in a population is the first step in providing information to help control the spread of the virus, but knowing which variants are present provides additional but very useful information."
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Environment
| 2,021 |
January 19, 2021
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https://www.sciencedaily.com/releases/2021/01/210119085240.htm
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New tool removes chemotherapy drugs from water systems
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'What goes in, must come out' is a familiar refrain. It is especially pertinent to the challenges facing UBC researchers who are investigating methods to remove chemicals and pharmaceuticals from public water systems.
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Cleaning products, organic dyes and pharmaceuticals are finding their ways into water bodies with wide-ranging negative implications to health and the environment, explains Dr. Mohammad Arjmand, an assistant professor of mechanical engineering at UBC Okanagan.And while pharmaceuticals like a chemotherapy drug called methotrexate can be highly effective for patients, once the drugs vacate their bodies they become a high risk for human health and the environment."Methotrexate is an anti-cancer drug used at a high dose in chemotherapy to treat cancer, leukemia, psoriasis, rheumatoid arthritis and other inflammatory diseases," he says. "However, the drug is not absorbed by the body and ends up in water channels from hospital waste, sewage and surface waters."Removing these types of contaminants from wastewater can be costly and complicated explains Arjmand, who is a Canada Research Chair in Advanced Materials and Polymer Engineering."We work on modifying the structure of adsorbent nanomaterials to control their ability to attract or repel chemicals," says Arjmand.While his team of researchers was looking at methods to remove the anti-cancer drugs from water supplies -- they designed a porous nanomaterial, called a metal-organic framework (MOF), that is capable of adsorbing these pollutants from water.Adsorption, he explains, takes place when the molecules of a chemical adhere to the surface of a solid substance -- in this case, the chemotherapy drug sticks to the surface of the adsorbent which is Arjmand's MOF."We precisely engineer the structure of our MOFs to remove the anti-cancer drug from aqueous solutions quickly," says Dr. Farhad Ahmadijokani, a doctoral student in the Nanomaterials and Polymer Nanocomposites Laboratory directed by Arjmand.Arjmand points out the MOF is an affordable technique for the removal of chemicals from liquids and waters and is an effective method to improve wastewater systems."The high-adsorption capacity, good recyclability and excellent structural stability make our MOF an impressive candidate for the removal of methotrexate from the aqueous solutions," he adds. "Our research shows that particular pharmaceutical can be adsorbed rapidly and effectively onto our aluminum-based metal-organic framework."
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Environment
| 2,021 |
January 15, 2021
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https://www.sciencedaily.com/releases/2021/01/210115155338.htm
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Glass frogs living near roaring waterfalls wave hello to attract mates
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Most frogs emit a characteristic croak to attract the attention of a potential mate. But a few frog species that call near loud streams -- where the noise may obscure those crucial love songs -- add to their calls by visually showing off with the flap of a hand, a wave of a foot or a bob of the head. Frogs who "dance" near rushing streams have been documented in the rainforests of India, Borneo, Brazil and, now, Ecuador.
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Conservation ecologist Rebecca Brunner, a Ph.D. candidate at the University of California, Berkeley, has discovered that the glass frog Sachatamia orejuela can be added to the list of species that make use of visual cues in response to their acoustic environments. This is the first time a member of the glass frog family (Centrolenidae) has been observed using visual communication in this manner."A handful of other frog species around the world use visual signaling, in addition to high-pitched calls, to communicate in really loud environments," Brunner said. "What's interesting is that these species are not closely related to each other, which means that these behaviors likely evolved independently, but in response to similar environments -- a concept called convergent evolution."Sachatamia orejuela glass frogs are native to the rainforests of Ecuador and Colombia. They are especially unique because they are almost exclusively found on rocks and boulders within the spray zones of waterfalls, where rushing water and slippery surfaces offer some protection against predators, and their green-gray color and semi-transparent skin make them nearly impossible to spot. As a result, little is known about this species' mating and breeding behavior.Brunner, who studies the bioacoustics of different ecological environments, was chest-deep in an Ecuadorean rainforest stream recording the call of a Sachatamia orejuela when she first observed this visual signaling behavior. As soon as she saw the frog repeatedly raising its front and back legs, Brunner climbed a slippery rock face and balanced on one foot to get video footage of the behavior."I was already over the moon because I had finally found a calling male after months of searching. Before our publication, there was no official record of this species' call, and basic information like that is really important for conservation," Brunner said. "But then I saw it start doing these little waves, and I knew that I was observing something even more special."While she filmed, the frog continued to wave its hands and feet and bob its head. She also observed another male Sachatamia orejuela glassfrog a few meters away performing the same actions."This is a really exhilarating discovery because it's a perfect example of how an environment's soundscape can influence the species that live there. We've found that Sachatamia orejuela has an extremely high-pitched call, which helps it communicate above the lower-pitched white noise of waterfalls. And then to discover that it also waves its hands and feet to increase its chances of being noticed -- that's a behavior I've always loved reading about in textbooks, so it is beyond thrilling to be able to share another amazing example with the world," said Brunner.Though the COVID-19 pandemic has put a pause on Brunner's fieldwork, she hopes to return to Ecuador soon to continue her research, which links bioacoustics and conservation."One of the best things about fieldwork is that nature is always full of surprises -- you never know what discoveries you may happen upon," Brunner said. "I hope our findings can serve as a reminder that we share this planet with incredible biodiversity. Conserving ecosystems that support species like Sachatamia orejuela is important not only for our well-being, but also for our sense of wonder."Video:
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Environment
| 2,021 |
January 15, 2021
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https://www.sciencedaily.com/releases/2021/01/210115115240.htm
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Researchers trace geologic origins of Gulf of Mexico 'super basin' success
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The Gulf of Mexico holds huge untapped offshore oil deposits that could help power the U.S. for decades.
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The energy super basin's longevity, whose giant offshore fields have reliably supplied consumers with oil and gas since the 1960s, is the result of a remarkable geologic past -- a story that began 200 million years ago among the fragments of Pangea, when a narrow, shallow seaway grew into an ocean basin, while around it mountains rose then eroded away.The processes that shaped the basin also deposited and preserved vast reserves of oil and gas, of which only a fraction has been extracted. Much of the remaining oil lies buried beneath ancient salt layers, just recently illuminated by modern seismic imaging. That's the assessment of researchers at The University of Texas at Austin, who reviewed decades of geological research and current production figures in an effort to understand the secret behind the basin's success.Because of its geological history, the Gulf of Mexico remains one of the richest petroleum basins in the world. Despite 60 years of continuous exploration and development, the basin's ability to continue delivering new hydrocarbon reserves means it will remain a significant energy and economic resource for Texas and the nation for years to come, said lead author John Snedden, a senior research scientist at the University of Texas Institute for Geophysics (UTIG)."When we looked at the geologic elements that power a super basin -- its reservoirs, source rocks, seals and traps -- it turns out that in the Gulf of Mexico, many of those are pretty unique," he said.The research was featured in a December 2020 special volume of the According to the paper, the geologic elements that have made the Gulf of Mexico such a formidable petroleum resource include a steady supply of fine- and coarse-grained sediments, and salt: thick layers of it buried in the Earth, marking a time long ago when much of the ancient sea in the basin evaporated.Geologically, salt is important because it can radically alter how petroleum basins evolve. Compared to other sedimentary rocks, it migrates easily through the Earth, creating space for oil and gas to collect. It helps moderate heat and keeps hydrocarbon sources viable longer and deeper. And it is a tightly packed mineral that seals oil and gas in large columns, setting up giant fields."The Gulf of Mexico has a thick salt canopy that blankets large portions of the basin and prevented us for many years from actually seeing what lies beneath," Snedden said. "What has kept things progressing is industry's improved ability to see below the salt."According to the paper, the bulk of the northern offshore basin's potential remains in giant, deepwater oil fields beneath the salt blanket. Although reaching them is expensive and enormously challenging, Snedden believes they represent the best future for fossil fuel energy. That's because the offshore -- where many of the giant fields are located -- offers industry a way of supplying the world's energy with fewer wells, which means less energy expended per barrel of oil produced.Snedden said there is still much to learn about hydrocarbons beneath the Gulf of Mexico, how they got there and how they can be safely accessed. This is especially true in the southern Gulf of Mexico, which was closed to international exploration until 2014. One of the few publicly available datasets was a series of UTIG seismic surveys conducted in the 1970s. Now, a wealth of prospects is emerging from new seismic imaging of the southern basin's deepwater region."When you look at recent U.S. oil and gas lease sales, Mexico's five-year plan, and the relatively small carbon footprint of the offshore oil and gas industry, I think it's clear that offshore drilling has an important future in the Gulf of Mexico," Snedden said.Snedden's research was conducted within UTIG for the Gulf Basin Depositional Synthesis project (which he directs). The project has been continuously funded by an industry consortium since 1995. UTIG is a unit of the Jackson School of Geosciences.
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Environment
| 2,021 |
January 14, 2021
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https://www.sciencedaily.com/releases/2021/01/210114163927.htm
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Scientists discover electric eels hunting in a group
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Deep in the Brazilian Amazon River basin, scientists led by the Smithsonian's National Museum of Natural History fish research associate C. David de Santana discovered a small, river-fed lake filled with more than 100 adult electric eels, many of which were upwards of 4 feet long. On its own, this was an intriguing discovery, electric eels -- a type of knifefish rather than true eels -- were thought to be solitary creatures.
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But in this lake along the banks of the Iriri River in Brazil's state of Pará, the researchers witnessed the eels working together to herd small fish called tetras into tightly packed balls. Then groups of up to 10 eels periodically split off to form cooperative hunting parties, not unlike packs of wolves or pods of killer whales. Those smaller groups then surrounded the prey ball and launched simultaneous electric attacks, stunning the tetras into submission."This is an extraordinary discovery," de Santana said. "Nothing like this has ever been documented in electric eels."De Santana is the senior author of a new paper describing this novel behavior in the Jan. 14 issue of the journal "Hunting in groups is pretty common among mammals, but it's actually quite rare in fishes," de Santana said. "There are only nine other species of fishes known to do this, which makes this finding really special."This new paper is the latest in a string of revelations driven by de Santana's investigations of the mysterious lives of South America's electric fishes. His pioneering expeditions into the murky, remote waters of the Amazon and its many tributaries have brought to light 85 new species of electric fishes. Just last year, he tripled the number of known species of electric eels, which had stood at one for roughly 250 years.One of the new species of electric eel presented in his 2019 paper, Volta's electric eel (Electrophorus voltai), is capable of producing 860-volt electric shocks -- the strongest electric discharge of any animal on Earth and 210 volts higher than the previous record. The freshly described Volta's electric eel, which can reach lengths of 8 feet, is also the species behind the social hunting strategy at the center of de Santana's new research."If you think about it, an individual of this species can produce a discharge of up to 860 volts -- so in theory if 10 of them discharged at the same time, they could be producing up to 8,600 volts of electricity," de Santana said. "That's around the same voltage needed to power 100 light bulbs."Direct measurements of these simultaneous shocks are one of the things de Santana and his colleagues hope to collect on their next expedition to the remote waterways of the Amazon basin. Fortunately for de Santana, who has been shocked more than once by individual eels in the field, the shock only lasts about two-thousandths of a second, but it is enough to cause a painful muscle spasm that might knock a person off their feet.De Santana's team first witnessed Volta's electric eel hunting in groups during a field expedition in August of 2012. Douglas Bastos, a then Master of Science candidate at Brazil's Instituto Nacional de Pesquisas da Amazônia (INPA) and the paper's first author, travelled five days by boat to explore the fish diversity of the Iriri River. Bastos, now a scientist at INPA, discovered a small lake directly connected with the Iriri River, and to his amazement, the lake held more than 100 adult electric eels.A subsequent expedition in October 2014 found a similarly prodigious collection of Volta's electric eels in the same locality, which allowed Bastos to document the behavior in greater detail and confirm that it was not just a one-time event. In all, the team logged 72 hours of continuous observation of the eels congregating in this location along the Iriri River.For the majority of the day and the night, the eels lay almost motionless in the deeper end of the lake, only occasionally coming to the surface to breathe -- electric eels get the vast majority of their oxygen from air, an adaptation in response to the low-oxygen waters they sometimes inhabit. But at dusk and dawn the congregation began to stir.In these twilight hours, the eels started interacting with each other and then began swimming in a large circle. This churning circle of electric eels corralled thousands of the 1-to-2-inch tetras into tighter and tighter shoals. The researchers watched the group herding the concentrated tetras from the deeper end of the lake -- around 12 feet deep -- to shallow, 3-foot deep waters.With the tetras trapped by the main group, de Santana says bands of two to 10 eels would separate, move in closer and then launch joint electric attacks on the prey ball. The electric shocks sent the tetras flying out of the water, but when they splashed down the small fish were stunned and motionless. Finally, the attacking eels and their compatriots easily picked off their defenseless prey. According to de Santana, each dawn or dusk hunting ritual took around one hour and contained between five to seven high-voltage attacks."This is the only location where this behavior has been observed, but right now we think the eels probably show up every year," de Santana said. "Our initial hypothesis is that this is a relatively rare event that occurs only in places with lots of prey and enough shelter for large numbers of adult eels."In de Santana's estimation, the team's interviews with locals would have turned up tales of writhing pools filled with electric eels if these gatherings were common. "These animals can be 8 feet long and produce 860-volt electric shocks; if 100 of them being in one place was a common occurrence, I think we would have heard about it before now."But when the conditions are right, this hunting technique allows the eels to subdue huge quantities of prey that are normally too evasive to capture. Electric eels customarily feed alone at night by sneaking up on sleeping fish and jolting them into an easy-to-eat torpor.De Santana and his team hope that their newly launched citizen scientist program called Projeto Poraquê may help locate more of these special aggregations of eels. The project, named for an Indigenous Brazilian word for electric eel, will allow users to report sightings and log observations.Now, de Santana and his colleagues are in the early stages of organizing the next expedition to this unique location along the Iriri. They hope to collect additional tissue samples and mark individual eels with radio tags to understand possible kin relations and hierarchy within the group. De Santana will also aim to take direct measurements of the electrical discharges produced during group hunting to assess their maximum voltage and to determine whether the eels might also be using low-voltage shocks to communicate and orchestrate their efforts, similar to how some marine mammals such as whales and dolphins use sound to coordinate when hunting their prey.Many of these measurements will be challenging to collect in the field, so de Santana has secured permits to collect eight to 10 adult eels and bring them to a special facility in Germany where he and his collaborators can conduct more controlled tests, which could later be replicated in the field. This would be the first time a group of adult Volta's electric eels has been held in captivity together.With the Amazon under threat from deforestation, fire and climate change, de Santana said there is a profound sense of urgency to accelerate biodiversity assessment in the region. "Electric eels aren't in immediate danger, but their habitats and ecosystems are under immense pressure. This paper is an example of how much we still don't know, how many organisms whose life histories we don't yet understand."
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Environment
| 2,021 |
January 14, 2021
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https://www.sciencedaily.com/releases/2021/01/210114134039.htm
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Lead poisoning of children
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Decades after the industrialized world largely eliminated lead poisoning in children, the potent neurotoxin still lurks in one in three children globally. A new study in Bangladesh by researchers at Stanford University and other institutions finds that a relatively affordable remediation process can almost entirely remove lead left behind by unregulated battery recycling -- an industry responsible for much of the lead soil contamination in poor and middle-income countries -- and raises troubling questions about how to effectively eliminate the poison from children's bodies.
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"Once the lead is in the environment, it stays there pretty much indefinitely without remediation," said study lead author Jenna Forsyth, a postdoctoral research fellow at the Stanford Woods Institute for the Environment. "Ultimately, we want to work toward a world in which battery recycling is done safely, and lead never makes it into the soil or people's bodies in the first place."Among toxins, lead is a supervillain. There is no safe level of exposure to lead, which damages nearly every system in the body. Early childhood exposure leads to irreversible brain damage and permanently lowered IQ, among other severe symptoms. Worldwide, one in three children suffers from lead poisoning, according to a recent report by Unicef and international NGO Pure Earth that describes the problem as "a much greater threat to the health of children than previously understood." The annual cost of resulting lost productivity is estimated to be nearly $1 trillion dollars globally and $16 billion in Bangladesh alone.Lead acid batteries, such as those used in many cars and backup power storage systems, account for at least 80% of global lead use. In poor and middle-income countries, informal or "backyard" recycling of leaded batteries often uses highly polluting techniques, such as open-pit smelting, that put approximately 16 million people at risk of lead poisoning. An earlier assessment in Bangladesh found nearly 300 such recycling sites with elevated soil lead concentrations and estimated that nearly 700,000 people across the country are living within the contaminated sites.To better understand informal battery recycling's impact on children, study partners from the International Centre for Diarrheal Disease Research, Bangladesh, observed daily activities of people living adjacent to an abandoned battery recycling operation in rural Bangladesh and surveyed childcare givers. They noted, for instance, that women and children were regular visitors to the abandoned battery recycling site, spending hours a day there. The residents explored the area, scavenged battery scraps to use as household materials or toys, and even collected soil colored white by smelting ash to add visual appeal to their home exteriors, yards and earthen stoves. Children often played in the dirt, while women collected firewood and building materials or hung laundry out for drying in the area.The researchers also tested children's blood before and after a multi-phased intervention that involved removing and burying contaminated soil, cleaning area households and educating residents about the dangers of soil lead exposure. Study partners from Dhaka University's Department of Geology and Pure Earth conducted the remediation work.Blood tests conducted prior to the remediation work showed many children had lead in their blood at levels up to 10 times higher than what the Centers for Disease Control and Prevention considers elevated. And while the remediation effort led to a 96% reduction in lead soil concentrations over 14 months, the researchers were surprised to find child blood lead levels decreased only 35% on average during the same period.The discrepancy may lie in the children's chronic soil lead exposure over a long enough time that lead stored in their bones continued to leach into their blood more than a year after the soil had been cleaned. A likely contributing reason, according to the researchers: other sources of lead exposure, such as turmeric adulterated with lead chromate and lead soldered cans used for food storage.Additionally, the research team's housecleaning efforts were unable to remove and wash mattresses and upholstered furniture, which could have continued to harbor lead-contaminated dust. Other potential ongoing sources of contamination could have been home foundations or earthen stoves that local women amended with soil from the site."We are gratified that focused efforts to clean up the environment can help," said study co-author Stephen Luby, a professor of infectious diseases at Stanford's School of Medicine. "But with the huge burden of lead toxicity on children globally, more radical efforts to remove lead from the economy are needed."Since 2014, Forsyth, Luby and other Stanford researchers have worked in rural Bangladesh to assess lead exposure. With funding from the Stanford Woods Institute for the Environment's Environmental Venture Projects program, they first conducted a population assessment that found more than 30% of pregnant women had elevated blood lead levels.Although the total cost of supplies and labor to implement the intervention -- $40,300 -- was relatively cheap by developed world standards, it's likely unfeasible in many regions of the developing world. The researchers suggest several ways to lower costs for such interventions, such as prioritizing house cleaning for children with the highest blood lead levels, but they emphasize the greater imperative to shift incentives away from informal battery recycling altogether.Forsyth and Luby, together with researchers at Stanford's School of Earth, Energy & Environmental Sciences, Graduate School of Business, d.school and International Policy Studies Program; are part of an initiative aimed at eliminating lead from the value chain or otherwise find ways to ensure it does not contaminate the environment. The effort, funded by the Stanford King Center on Global Development, focuses on reducing lead exposure from batteries and turmeric in Bangladesh.
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Environment
| 2,021 |
January 14, 2021
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https://www.sciencedaily.com/releases/2021/01/210114111910.htm
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How aerosols are formed
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Aerosols are suspensions of fine solid particles or liquid droplets in a gas. Clouds, for example, are aerosols because they consist of water droplets dispersed in the air. Such droplets are produced in a two-step process: first, a condensation nucleus forms, and then volatile molecules condense onto this nucleus, producing a droplet. Nuclei frequently consist of molecules different to those that condense onto them. In the case of clouds, the nuclei often contain sulphuric acids and organic substances. Water vapour from the atmosphere subsequently condenses onto these nuclei.
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Scientists led by Ruth Signorell, Professor at the Department of Chemistry and Applied Biosciences, have now gained new insights into the first step of aerosol formation, nucleation. "Observations have shown that the volatile components can also influence the nucleation process," Signorell says, "but what was unclear was how this was happening at the molecular level." Previously it was impossible to observe the volatile components during nucleation in an experimental setting. Even in a famous CERN experiment on cloud formation, the "Cloud" experiment, certain volatile components could not be directly detected.The ETH researchers developed an experiment aimed at the first microseconds of the nucleation process. In the experiment, the particles formed remain intact during this time and can be detected using mass spectrometry. The scientists looked at nucleation in various gas mixtures containing COAn analysis of the experimental data revealed that this acceleration is the result of the volatile components catalysing the nucleation of other, less volatile components. They do this by forming short-lived, heterogeneous molecular aggregates, known as chaperon complexes. "Because temperature determines the volatility of gas components, it also plays a decisive role in these processes," Signorell explains.One reason the new research results are interesting is that they improve the understanding of nucleation, its molecular mechanisms and speed, in order to properly account for it in models for, say, cloud formation in the atmosphere. In addition, the results should help to improve the efficiency of technical processes for producing aerosols -- such as the use of rapid cooling to capture CO
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Environment
| 2,021 |
January 14, 2021
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https://www.sciencedaily.com/releases/2021/01/210114085430.htm
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Low cost chlorine dispensing device improves tap water safety in low-resource regions
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A team of researchers led by engineers at Tufts University's School of Engineering and Stanford University's Program on Water, Health and Development have developed a novel and inexpensive chlorine dispensing device that can improve the safety of drinking water in regions of the world that lack financial resources and adequate infrastructure. With no moving parts, no need for electricity, and little need for maintenance, the device releases measured quantities of chlorine into the water just before it exits the tap. It provides a quick and easy way to eliminate water-borne pathogens and reduce the spread of high mortality diseases such as cholera, typhoid fever and diarrhea.
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According to the CDC, more than 1.6 million people die from diarrheal diseases every year and half of those are children. The authors suggest that the solution to this problem could be relatively simple.In communities and regions that do not have the resources to build water treatment plants and distribution infrastructure, the researchers found that the device can provide an effective, alternative means of water treatment at the point of collection. The device was installed and tested at several water collection stations, or kiosks, across rural areas in Kenya.The study, which also looks at the economic feasibility and local demand for the system, was published today in the journal "The idea we pursued was to minimize the user burden by automating water treatment at the point of collection," said Amy J. Pickering, former professor of civil and environmental engineering at Tufts (now at Stanford) and corresponding author of the study. "Clean water is central to improving human health and alleviating poverty. Our goal was to design a chlorine doser that could fit onto any tap, allowing for wide-scale implementation and increasing accessibility to a higher-level of safe water service."Water is a simple substance, but a complex global health issue in both its availability and quality. Although it has long been a focus of the World Health Organization and other NGO's, 2.1 billion people still lack access to safe water at home (WHO). In areas of the world where finances and infrastructure are scarce, water may be delivered to communities by pipe, boreholes or tube wells, dug wells, and springs. Unfortunately, 29 percent of the global population uses a source that fails to meet the Sustainable Development Goal (SDG) criteria for safely managed water -- accessible and available when needed, and free from fecal and chemical contamination. In many places, access to safe water is out of reach due to the lack of available funds to create and support water treatment facilities.The device works on the principle of a physical phenomenon in fluid dynamics called the Venturi effect, in which a non-compressible fluid flows at a faster rate when it runs from a wider to a narrower passage. In the device, the water passes through a so-called pinch valve. The fast-moving water stream draws in chlorine from a tube attached to the pinch valve. A needle valve controls the rate and thus amount of chlorine flowing into the water stream. The simple design could allow the device to be manufactured for $35 USD at scale."Rather than just assume we made something that was easier to use, we conducted user surveys and tracked the performance of the devices over time," said study co-author Jenna Davis, a professor of civil and environmental engineering at Stanford, director of Stanford's Program on Water, Health and Development, and co-PI of the Lotus Water project. This research is an extension of Lotus Water, which aims to provide reliable and affordable disinfection services for communities most at risk of waterborne illness.A six-month evaluation in Kenya revealed stable operation of six of seven installed devices; one malfunctioned due to accumulation of iron deposits, a problem likely solvable with a pre-filter. Six of the seven sites were able to maintain payment for and upkeep of the device, and 86.2 percent of 167 samples taken from the devices throughout the period showed chlorine above the WHO recommended minimum level to ensure safe water, and below a threshold determined for acceptable taste. Technical adjustments were required in less than 5 percent of visits by managers of the kiosks. In a survey, more than 90 percent of users said they were satisfied with the quality of the water and operation of the device."Other devices and methods have been used to treat water at the point of collection," said Julie Powers, PhD student at Tufts School of Engineering and first author of the study. "but the Venturi has several advantages. Perhaps most importantly, it doesn't change the way people collect their water or how long it takes -- there's no need for users to determine the correct dosing or spend extra time- just turn on the tap. Our hope is the low cost and high convenience will encourage widespread adoption that can lead to improved public health."Future work examining the effect of the in-line chlorination device on diarrhea, enteric infections, and child mortality could further catalyze investment and scaling up this technology, said Powers.Funding for the development of the device and the study was provided by the Stanford Woods Institute for the Environment at Stanford University and the Stanford Institute for Innovation in Developing Economies.
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Environment
| 2,021 |
January 14, 2021
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https://www.sciencedaily.com/releases/2021/01/210114085405.htm
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Bees respond to wildfire aftermath by producing more female offspring
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Researchers at Oregon State University have found that the blue orchard bee, an important native pollinator, produces female offspring at higher rates in the aftermath of wildfire in forests.
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The more severe the fire had been, the greater percentage of females -- more than 10% greater in the most badly burned areas relative to areas that burned the least severely."This is one of the first studies that has looked at how forest fire severity influences bee demography," said Jim Rivers, an animal ecologist with the OSU College of Forestry. "Sex ratio varied under different fire conditions but the number of young produced did not, which indicates bees altered the sex of their offspring depending on the degree of fire severity."Female bees control the sex of their offspring, laying eggs fertilized with sperm that become females, or non-fertilized eggs that become males.Bees pollinate many of the flowering plants that make up native ecosystems and food chains Understanding how fire -- expected to increase in frequency and severity -- influences their reproductive outputs is an important part of knowing how post-fire management actions could help or harm bees."We placed bees on different sites within recently burned mixed-conifer forest in southwestern Oregon and used them as a measuring stick to tell us how good the bee habitat was," said Sara Galbraith, a postdoctoral researcher in the College of Forestry. "Adjusting offspring production toward the more expensive offspring sex shows a functional response to changes in habitat quality via an increased density of flowering plants."In general, pollinators benefit from canopy-reducing fires in dense conifer forest ecosystems; flowering plant abundance usually increases for several years following a fire, resulting in food resources that enhance wild bee diversity and abundance.Bees are the most important among the Earth's pollinators, which combine for an estimated $100 billion in global economic impact each year. Oregon is home to more than 600 species of native bees.Animal pollinators enhance the reproduction of nearly 90% of the Earth's flowering plants, including many food crops.Pollinators are an essential component of insect and plant biodiversity. Bees are the standard bearer because they're usually present in the greatest numbers and because they're the only pollinator group that feeds exclusively on nectar and pollen their entire life.For this study involving the blue orchard bee, known scientifically as Osmia lignaria, Galbraith, Rivers and James Cane of the U.S. Department of Agriculture set up nest blocks containing a standardized number and sex ratio of pre-emergent adult bees.They then looked at the relationship between fire severity and reproductive output, sex ratio and offspring mass at the local (within 100 meters of the blocks) and landscape (750 meters) scales. Female bees forage across both scales when caring for offspring."In fire-prone landscapes, there is variation in species-level response to wildfire that serves to maintain ecosystem structure and function," Rivers said. "With the blue orchard bee and similar species, foraging females invest in larger progeny and more females when more resources are available."The findings showed that burned mixed-conifer forest provides forage for the blue orchard bee along a gradient of severity, and that the rise in floral resources that comes after high-severity fire causes females to reallocate resources to the larger and more costly sex -- females -- when nesting."Our study revealed more female progeny than is typically observed with blue orchard bees," Galbraith said. "The greater proportion of females in areas surrounded by a more severely burned landscape indicates an investment in more female offspring because of greater resource availability."Findings were published in
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Environment
| 2,021 |
January 13, 2021
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https://www.sciencedaily.com/releases/2021/01/210113144442.htm
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Robotic swarm swims like a school of fish
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Schools of fish exhibit complex, synchronized behaviors that help them find food, migrate and evade predators. No one fish or team of fish coordinates these movements nor do fish communicate with each other about what to do next. Rather, these collective behaviors emerge from so-called implicit coordination -- individual fish making decisions based on what they see their neighbors doing.
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This type of decentralized, autonomous self-organization and coordination has long fascinated scientists, especially in the field of robotics.Now, a team of researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and the Wyss Institute for Biologically Inspired Engineering have developed fish-inspired robots that can synchronize their movements like a real school of fish, without any external control. It is the first time researchers have demonstrated complex 3D collective behaviors with implicit coordination in underwater robots."Robots are often deployed in areas that are inaccessible or dangerous to humans, areas where human intervention might not even be possible," said Florian Berlinger, a PhD Candidate at SEAS and Wyss and first author of the paper. "In these situations, it really benefits you to have a highly autonomous robot swarm that is self-sufficient. By using implicit rules and 3D visual perception, we were able to create a system that has a high degree of autonomy and flexibility underwater where things like GPS and WiFi are not accessible."The research is published in The fish-inspired robotic swarm, dubbed Blueswarm, was created in the lab of Radhika Nagpal, the Fred Kavli Professor of Computer Science at SEAS and Associate Faculty Member at the Wyss Institute. Nagpal's lab is a pioneer in self-organizing systems, from their 1,000 robot Kilobot swarm to their termite-inspired robotic construction crew.However, most previous robotic swarms operated in two-dimensional space. Three-dimensional spaces, like air and water, pose significant challenges to sensing and locomotion.To overcome these challenges, the researchers developed a vision-based coordination system in their fish robots based on blue LED lights. Each underwater robot, called a Bluebot, is equipped with two cameras and three LED lights. The on-board, fish-lens cameras detect the LEDs of neighboring Bluebots and use a custom algorithm to determine their distance, direction and heading. Based on the simple production and detection of LED light, the researchers demonstrated that the Blueswarm could exhibit complex self-organized behaviors, including aggregation, dispersion and circle formation."Each Bluebot implicitly reacts to its neighbors' positions," said Berlinger. "So, if we want the robots to aggregate, then each Bluebot will calculate the position of each of its neighbors and move towards the center. If we want the robots to disperse, the Bluebots do the opposite. If we want them to swim as a school in a circle, they are programmed to follow lights directly in front of them in a clockwise direction. "The researchers also simulated a simple search mission with a red light in the tank. Using the dispersion algorithm, the Bluebots spread out across the tank until one comes close enough to the light source to detect it. Once the robot detects the light, its LEDs begin to flash, which triggers the aggregation algorithm in the rest of the school. From there, all the Bluebots aggregate around the signaling robot."Our results with Blueswarm represent a significant milestone in the investigation of underwater self-organized collective behaviors," said Nagpal. "Insights from this research will help us develop future miniature underwater swarms that can perform environmental monitoring and search in visually-rich but fragile environments like coral reefs. This research also paves a way to better understand fish schools, by synthetically recreating their behavior."The research was co-authored by Dr. Melvin Gauci, a former Wyss Technology Development Fellow. It was supported in part by the Office of Naval Research, the Wyss Institute for Biologically Inspired Engineering, and an Amazon AWS Research Award.Video:
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Environment
| 2,021 |
January 13, 2021
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https://www.sciencedaily.com/releases/2021/01/210113120721.htm
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Flashing plastic ash completes recycling
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Pyrolyzed plastic ash is worthless, but perhaps not for long.
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Rice University scientists have turned their attention to Joule heating of the material, a byproduct of plastic recycling processes. A strong jolt of energy flashes it into graphene.The technique by the lab of Rice chemist James Tour produces turbostratic graphene flakes that can be directly added to other substances like films of polyvinyl alcohol (PVA) that better resist water in packaging and cement paste and concrete, dramatically increasing their compressive strength.The research appears in the journal Like the flash graphene process the lab introduced in 2019, pyrolyzed ash turns into turbostratic graphene. That has weaker attractive interactions between the flakes, making it easier to mix them into solutions.Last October, the Tour lab reported on a process to convert waste plastic into graphene. The new process is even more specific, turning plastic that is not recovered by recycling into a useful product."This work enhances the circular economy for plastics," Tour said. "So much plastic waste is subject to pyrolysis in an effort to convert it back to monomers and oils. The monomers are used in repolymerization to make new plastics, and the oils are used in a variety of other applications. But there is always a remaining 10% to 20% ash that's valueless and is generally sent to landfills."Now we can convert that ash into flash graphene that can be used to enhance the strength of other plastics and construction materials," he said.Pyrolysis involves heating a material to break it down without burning it. The products of pyrolyzed, recycled plastic include energy-rich gases, fuel oils, waxes, naphtha and virgin monomers from which new plastic can be produced.But the rest -- an estimated 50,000 metric tons in the United States per year -- is discarded."Recyclers do not turn large profits due to cheap oil prices, so only about 15% of all plastic gets recycled," said Rice graduate student Kevin Wyss, lead author of the study. "I wanted to combat both of these problems."The researchers ran a pair of experiments to test the flashed ash, first mixing the resulting graphene with PVA, a biocompatible polymer being investigated for medical applications, fuel cell polymer electrolyte membranes and environmentally friendly packaging. It has been held back by the base material's poor mechanical properties and vulnerability to water.Adding as little as 0.1% of graphene increases the amount of strain the PVA composite can handle before failure by up to 30%, they reported. It also significantly improves the material's resistance to water permeability.In the second experiment, they observed significant increases in compressive strength by adding graphene from ash to Portland cement and concrete. Stronger concrete means less concrete needs to be used in structures and roads. That curtails energy use and cuts pollutants from its manufacture.The National Science Foundation, the Air Force Office of Scientific Research and the Department of Energy supported the research.
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Environment
| 2,021 |
January 13, 2021
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https://www.sciencedaily.com/releases/2021/01/210113120706.htm
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A fly's eye view of evolution
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The fascinating compound eyes of insects consist of hundreds of individual eyes known as "facets." In the course of evolution, an enormous variety of eye sizes and shapes has emerged, often representing adaptations to different environmental conditions. Scientists, led by an Emmy Noether research group at the University of Göttingen, together with scientists from the Andalusian Centre for Developmental Biology (CABD) in Seville, have now shown that these differences can be caused by very different changes in the genome of fruit flies. The study was published in the journal
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Anyone who has seen hoverflies manoeuvring through the air and, quick as a flash, changing direction, has probably witnessed a mating attempt in which the male, with breath-taking accuracy, pursues a fast-moving female. To carry out this specialised visual task, the huge compound eyes of hoverflies consist of up to 6,000 individual facets. There are special individual facets directed towards the sky that show particularly high resolution. In contrast, bark beetles, which spend most of their time burrowing inside wood, rarely rely on visual information. Hence, they have developed very small eyes with a maximum of 300 facets. "This enormous diversity is particularly impressive because previous comparative studies have shown that the development of insect eyes, and for that matter our own eyes as well, is controlled by very similar processes and genes," says Dr Nico Posnien from Göttingen University, the leader of the study. "It is especially exciting to understand how, in the face of very similar genes, such a diversity of size and shape of eyes can arise." Since many of the proteins coded by genes work together in regulatory networks to control the development of complex organs, the question arises whether similar differences in eye size are caused by changes at comparable sites within the networks. As a model for their study, the researchers used several species of the genus Drosophila, some of which we would recognise as the pesky fruit flies found in everyone's kitchen.A Drosophila species native to Mauritius has up to 250 facets more than a closely related species. Although the basic developmental processes are very similar in both studied species, numerous differences were found in their genomes that could explain the observed differences in eye size. Detailed analysis of eye development in both species suggests that changes in an important central node of the gene network lead to the formation of significantly larger eyes in the species native to Mauritius. "Interestingly, in similar work on other Drosophila species, changes in completely different nodes have been observed. Therefore, our data show that differences in the number of facets can be caused by very different mechanisms," summarises the first author of the study, Dr Elisa Buchberger from the University of Göttingen."The new data suggest that differences in the number of single eyes in different Drosophila species arose several times independently in evolution," says Dr Micael Reis. He is first author of a study published last year by the Göttingen research group. Overall, the work of the Göttingen group contributes to a better understanding of the evolution of complex organs. Some of the methods established in this research could also be applied to studies in animal and plant breeding, specifically looking for changes in the genome that influence complex traits, such as milk production or fruit size. "In a next step, we would like to understand whether the different eye sizes have an influence on vision, and find out whether they are related to the lifestyle of the different fly species," says Posnien.
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Environment
| 2,021 |
January 13, 2021
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https://www.sciencedaily.com/releases/2021/01/210113100820.htm
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Blue-light stride in perovskite-based LEDs
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Researchers at Linköping University, Sweden, have developed efficient blue light-emitting diodes based on halide perovskites. "We are very excited about this breakthrough," says Feng Gao, professor at Linköping University. The new LEDs may open the way to cheap and energy-efficient illumination.
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Illumination is responsible for approximately 20% of global electricity consumption, a figure that could be reduced to 5% if all light sources consisted of light-emitting diodes (LEDs). The blue-white LEDs currently in use, however, need complicated manufacturing methods and are expensive, which makes it more difficult to achieve a global transition.LEDs manufactured from halide perovskites could be a cheaper and more eco-friendly alternative for both illumination and LED-based monitors. Perovskites are a family of semiconducting materials defined by their cubic crystal structure. They have good light-emitting properties and are easy to manufacture. Using elements from the halogen group, i.e. fluorine, chlorine, bromine and iodine, perovskites can be given properties that depend on the chemical composition of the crystal.LEDs for green and red light have already been created with perovskites, but one colour, blue, has so far been lacking, making it impossible to achieve white light."Blue light is the key to bringing light-emitting perovskites to practical applications. Our most recent breakthrough is one step on the way," says Feng Gao, professor at the Department of Physics, Chemistry and Biology at Linköping University.Feng Gao's research group, in collaboration with colleagues in Lund, Great Britain, Germany, China and Denmark, has managed to create halide perovskites that give stable emission in the wavelength range 451-490 nanometres -- corresponding to deep blue to sky blue colours. Max Karlsson is doctoral student at Linköping University and joint first author of the article now published in "Metal-halide perovskites are easily colour-tuneable over the whole visible spectrum by simple alloying. Unfortunately, they exhibit demixing and a blue LED turns green during operation. We have found a method that can prevent this colour shift by controlling the film crystallisation dynamics when creating the perovskite. These findings pave the way for stable perovskite alloys, not only for LEDs but also for solar cells."The challenge of creating blue light in perovskites is that it requires a chemical composition with a large fraction of chloride, which makes the perovskite unstable. Blue perovskite-based LEDs have previously been created with using what is known as the "quantum confinement technique," which gives low-intensity LEDs with poor efficiency. However, stable perovskites with the desired amount of chloride can be created with the aid of the "vapour-assisted crystallisation technique." Furthermore, the Linköping University researchers have achieved an energy efficiency of up to 11% for the blue perovskite-based LEDs."We have shown that blue light-emitting diodes based on halide perovskites can be both efficient and stable across a broad spectrum, without using quantum confinement. We have managed to create one of the most efficient blue perovskite-based LEDs so far known," says Weidong Xu, postdoc at Linköping University.The science of perovskites is a relatively new research field that has aroused major international interest, since it offers a great potential for developing cheap and efficient materials. Feng Gao, however, is quick to point out that the work they have done is basic research, and applications are still some way off in future."Perovskite LEDs are a young technology and have some way to go before they see the light of day. Currently, the short lifetime and poor performance of blue LEDs are the main obstacles for perovskite light-emitting diodes before they can start to compete with existing technologies such as light-emitting diodes based on organic and inorganic semiconductors. We will keep working on that to make PeLEDs comparable to the other technologies," says Feng Gao.Sources of research finance include an ERC Starting Grant, the Swedish Research Council, the Swedish Energy Agency, and through the Swedish Strategic Research Area in Advanced Functional Materials (AFM) at Linköping University.
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Environment
| 2,021 |
January 13, 2021
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https://www.sciencedaily.com/releases/2021/01/210113090914.htm
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Need to reduce work-related stress? It's a walk in the park
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Work causes so much stress that it's become a global public health issue. Stress's impact on mental and physical health can also hurt productivity and result in economic loss. A new study now finds that working people who regularly take walks in forests or greenspaces may have higher stress-coping abilities.
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In a study published in The study used survey data on more than 6,000 Japanese workers between 20 and 60 years old. It found stronger SOC among people who regularly took walks in forests or greenspaces."SOC indicates mental capacities for realizing and dealing with stress," Professor Sasahara says. "With workplace stress as a focal issue, there's a clear benefit in identifying everyday activities that raise SOC. It seems we may have found one."People find comfort in nature, and in countries like Japan urban greenspaces are increasing in popularity where nature isn't readily accessible. This means many workers in cities can easily take a walk among the trees.The researchers divided the survey respondents into four groups based on their frequency of forest/greenspace walking. Then, they compared their walking activity against attributes such as age, income, and marital status, and with the respondents' SOC scores, which were grouped as weak, middle, and strong.Those with strong SOC showed a significant correlation with both forest and greenspace walking at least once a week. This key finding implies the greater benefits of urban greening -- not just environmental, but also socioeconomic."Our study suggests that taking a walk at least once a week in a forest or greenspace can help people have stronger SOC," explains Professor Sasahara. "Forest/greenspace walking is a simple activity that needs no special equipment or training. It could be a very good habit for improving mental health and managing stress."
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Environment
| 2,021 |
January 12, 2021
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https://www.sciencedaily.com/releases/2021/01/210112125221.htm
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Advanced light reveals how different biofuels behave
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Vehicles have evolved to become more efficient and sophisticated, but their fuel hasn't necessarily evolved along with them. The Department of Energy is determined to identify cleaner burning and renewable alternatives to gasoline, and through the work of two UCF researchers, the DOE is one step closer to that goal.
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Research engineer Anthony C. Terracciano and Associate Professor Subith Vasu have developed a model that will help engine designers, fuel chemists and federal agencies determine whether certain biofuels should be implemented as an alternative fuel for vehicles.The research was conducted as part of the DOE's Co-Optimization of Fuels and Engines initiative, better known as Co-Optima. Findings were recently published in Nature "We worked with scientists from various U.S. government labs to come up with our research strategy," Vasu says.In prior Co-Optima research, Vasu and his team tested five of the most promising biofuels, including ethanol. For this research, Vasu and his team studied the biofuel diisobutylene (DIB), a natural byproduct of sugar."DIB has been down selected due to its promise as a potential drop-in biofuel for gasoline engines based on a variety of factors including its cost of production, compatibility with existing infrastructure, fuel and combustion properties," Vasu says.Using the Advanced Light Source, a powerful particle accelerator at the Lawrence Berkeley National Laboratory, they were able to identify 46 molecules that are present in the flames of DIB during ignition. This is the first time that DIB has been studied with this equipment."Our work specifically identifies the quantity of 46 molecules present within the DIB combustion environment just after ignition," Terracciano says. "This provides an unprecedentedly rich framework, which engineers and scientists can use to craft a complete understanding of the reaction environment using these DIB fuels."The researchers investigated the two most common sources of DIB, which are the alpha and beta strands. They created a combustion event in a jet-stirred reactor, a volume that is continuously stirred, at fixed conditions. The chemical reactions were then inhibited to create a molecular beam that was bombarded with ultraviolet light from the ALS to generate ions.This model may be readily implemented by any agency, and the knowledge will help fuel developers manufacture a product much quicker."Fuel chemistry for vehicles is complex from the design and considerations of engines, support infrastructure and emissions," Terracciano says. "Fuel engineers need to ensure that the sold fuels fit within the envelopes of the octane standard. By knowing the combustion properties of specific fuel components, blends can be manufactured with less empirical testing."
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Environment
| 2,021 |
January 12, 2021
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https://www.sciencedaily.com/releases/2021/01/210112110144.htm
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Unsure how to help reverse insect declines? Scientists suggest simple ways
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Entomologist Akito Kawahara's message is straightforward: We can't live without insects. They're in trouble. And there's something all of us can do to help.
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Kawahara's research has primarily focused on answering fundamental questions about moth and butterfly evolution. But he's increasingly haunted by studies that sound the alarm about plummeting insect numbers and diversity.Kawahara has witnessed the loss himself. As a child, he collected insects with his father every weekend, often traveling to a famous oak outside Tokyo whose dripping sap drew thousands of insects. It was there he first saw the national butterfly of Japan, the great purple emperor, Sasakia charonda. When he returned a few years ago, the oak had been replaced by a housing development. S. charonda numbers are in steep decline nationwide.While scientists differ on the severity of the problem, many findings point to a general downward trend, with one study estimating 40% of insect species are vulnerable to extinction. In response, Kawahara has turned his attention to boosting people's appreciation for some of the world's most misunderstood animals."Insects provide so much to humankind," said Kawahara, associate curator at the Florida Museum of Natural History's McGuire Center for Lepidoptera and Biodiversity. "In the U.S. alone, wild insects contribute an estimated $70 billion to the economy every year through free services such as pollination and waste disposal. That's incredible, and most people have no idea."Insects sustain flowering plants, the lynchpins of most land-based ecosystems, and provide food sources for birds, bats, freshwater fish and other animals. But they face a barrage of threats, including habitat loss, pesticides, pollution, invasive species and climate change. If human activities are driving the decline, Kawahara reasons, then people can also be a part of the solution.In an opinion piece published in a special edition of the If you have a lawn, mowing less can give insect populations a boost. Kawahara suggests reserving 10% of a landscape for insects, either actively replacing a monoculture of grass with native plants or simply leaving the space unmown. These miniature nature preserves provide crucial habitat and food reservoirs for insects, he said, particularly if they remain free of chemical pesticides and herbicides. Benefits for lawn-maintainers include less yardwork and lower expenses."Even a tiny patch could be hugely important for insects as a place to nest and get resources," Kawahara said. "It's a stepping stone they can use to get from one place to another. If every home, school and local park in the U.S. converted 10% of lawn into natural habitat, this would give insects an extra 4 million acres of habitat."If you don't have a lawn, you can still help by cultivating native plants in pots in window boxes or on balconies and patios.Nighttime light pollution has spiked since the 1990s, doubling in some of the world's most biodiverse places. Artificial lights are powerful attractants to nocturnal insects, which can exhaust themselves to death by circling bulbs or fall prey to predators that spot an easy target.You can give insects a hand -- and reduce your electric bill -- by turning off unnecessary lights after dark and using amber or red bulbs, which are less attractive to insects.Chemical pollutants in soaps for washing cars and building exteriors and in coal-tar-based driveway sealants can harm a variety of insect life. Kawahara recommends swapping these out for biodegradable soaps and soy-based sealants. In winter, trading rock salt for salt-free formulations is safer for both insects and pets.In the U.S., insects have historically been depicted as devourers of crops, disease vectors and hallmarks of poor sanitation, even though the vast majority do not harm humans. Kawahara said rethinking your own stereotypes of insects and gaining a better understanding of their beauty, diversity and roles is a first step in helping others appreciate them, too.He recalled leading schoolchildren on an insect-collecting trip during which a student found an elephant stag beetle, an enormous insect with massive jaws -- "one of the coolest, most amazing bugs," Kawahara said.The student wanted to step on the beetle, thinking it was a cockroach."Other students were grossed out, too," Kawahara said. "When I saw that, I was dumbfounded. If this was Japan, kids would be clamoring to be the first to get it and keep it as a pet. The juxtaposition of those cultural reactions was striking."He pointed to media characterizations of Asian giant hornets -- which he grew up seeing drink sap from the oak tree outside of Tokyo -- as "murder hornets" as another example of how framing insects as dangerous or disgusting has the power to evoke strong reactions from the public.As antidotes to unfounded fears, walk outdoors to look for local insect life or adopt pet insects, a simple, inexpensive way to introduce children to science, Kawahara said. Documenting what you see on platforms such as iNaturalist not only helps you learn more about your finds, but also provides data for scientific research.These small steps have the power to effect immediate changes for the planet's insects, Kawahara said."The best way for change to happen quickly is for everyone to pitch in. As individuals, we can all do these kinds of activities right away."
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Environment
| 2,021 |
January 11, 2021
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https://www.sciencedaily.com/releases/2021/01/210111135853.htm
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Scientists make sustainable polymer from sugars in wood
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Scientists from the University of Bath have made a sustainable polymer using the second most abundant sugar in nature, xylose.
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Not only does the new nature-inspired material reduce reliance on crude oil products, but its properties can also be easily controlled to make the material flexible or crystalline.The researchers, from the University's Centre for Sustainable and Circular Technologies, report the polymer, from the polyether family, has a variety of applications, including as a building block for polyurethane, used in mattresses and shoe soles; as a bio-derived alternative to polyethylene glycol, a chemical widely used in bio-medicine; or to polyethylene oxide, sometimes used as electrolyte in batteries.The team says additional functionality could be added to this versatile polymer by binding other chemical groups such as fluorescent probes or dyes to the sugar molecule, for biological or chemical sensing applications.The team can easily produce hundreds of grams of the material and anticipate that production would be rapidly scalable.Dr Antoine Buchard, Royal Society University Research Fellow and Reader at the Centre for Sustainable and Circular Technologies, led the study.He said: "We're very excited that we've been able to produce this sustainable material from a plentiful natural resource -- wood."The reliance of plastics and polymers on dwindling fossil fuels is a major problem, and bio-derived polymers -- those derived from renewable feedstocks such as plants -- are part of the solution to make plastics sustainable."This polymer is particularly versatile because its physical and chemicals properties can be tweaked easily, to make a crystalline material or more of a flexible rubber, as well as to introduce very specific chemical functionalities."Until now this was very difficult to achieve with bio-derived polymers."This means that with this polymer, we can target a variety of applications, from packaging to healthcare or energy materials, in a more sustainable way."Like all sugars, xylose occurs in two forms that are mirror images of each other -- named D and L.The polymer uses the naturally occurring D-enantiomer of xylose, however the researchers have shown that combining it with the L-form makes the polymer even stronger.The research team has filed a patent for their technology and is now interested in working with industrial collaborators to further scale up production and explore the applications of the new materials.
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Environment
| 2,021 |
January 11, 2021
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https://www.sciencedaily.com/releases/2021/01/210111115744.htm
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New process more efficiently recycles excess CO2 into fuel
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For years, researchers have worked to repurpose excess atmospheric carbon dioxide into new chemicals, fuels and other products traditionally made from hydrocarbons harvested from fossil fuels. The recent push to mitigate the climactic effects of greenhouse gases in the atmosphere has chemists on their toes to find the most efficient means possible. A new study introduces an electrochemical reaction, enhanced by polymers, to improve CO
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The results of the study led by University of Illinois Urbana-Champaign chemistry professor Andrew Gewirth and graduate student Xinyi (Stephanie) Chen are published in the journal Allowing CO"Copper metal is highly selective toward the type of carbon that forms ethylene," Gewirth said. "Different electrode materials will produce different chemicals like carbon monoxide instead of ethylene, or a mix of other carbon chemicals. What we have done in this study is to design a new kind of copper electrode that produces almost entirely ethylene."Previous studies have used other metals and molecular coatings on the electrode to help direct the COIn the lab, the team found that the new polymer-entrained electrodes were less likely to break down and produced more stable chemical intermediates, resulting in more efficient ethylene production. "We were able to convert CO"With the development of economic sources of electricity, combined with the increased interest in COThe International Institute for Carbon Neutral Energy Research, Shell's New Energy Research and Technology and the National Science Foundation supported this research.
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Environment
| 2,021 |
January 11, 2021
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https://www.sciencedaily.com/releases/2021/01/210111094306.htm
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New nanostructured alloy for anode is a big step toward revolutionizing energy storage
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Researchers in the Oregon State University College of Engineering have developed a battery anode based on a new nanostructured alloy that could revolutionize the way energy storage devices are designed and manufactured.
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The zinc- and manganese-based alloy further opens the door to replacing solvents commonly used in battery electrolytes with something much safer and inexpensive, as well as abundant: seawater.Findings were published today in "The world's energy needs are increasing, but the development of next-generation electrochemical energy storage systems with high energy density and long cycling life remains technically challenging," said Zhenxing Feng, a chemical engineering researcher at OSU. "Aqueous batteries, which use water-based conducting solutions as the electrolytes, are an emerging and much safer alternative to lithium-ion batteries. But the energy density of aqueous systems has been comparatively low, and also the water will react with the lithium, which has further hindered aqueous batteries' widespread use."A battery stores power in the form of chemical energy and through reactions converts it to the electrical energy needed to power vehicles, cellphones, laptops and many other devices and machines. A battery consists of two terminals -- the anode and cathode, typically made of different materials -- as well as a separator and electrolyte, a chemical medium that allows for the flow of electrical charge.In a lithium-ion battery, as its name suggests, a charge is carried via lithium ions as they move through the electrolyte from the anode to the cathode during discharge, and back again during recharging."Electrolytes in lithium-ion batteries are commonly dissolved in organic solvents, which are flammable and often decompose at high operation voltages," Feng said. "Thus there are obviously safety concerns, including with lithium dendrite growth at the electrode-electrolyte interface; that can cause a short between the electrodes."Dendrites resemble tiny trees growing inside a lithium-ion battery and can pierce the separator like thistles growing through cracks in a driveway; the result is unwanted and sometimes unsafe chemical reactions.Combustion incidents involving lithium-ion batteries in recent years include a blaze on a parked Boeing 787 jet in 2013, explosions in Galaxy Note 7 smartphones in 2016 and Tesla Model S fires in 2019.Aqueous batteries are a promising alternative for safe and scalable energy storage, Feng said. Aqueous electrolytes are cost-competitive, environmentally benign, capable of fast charging and high power densities and highly tolerant of mishandling.Their large-scale use, however, has been hindered by a limited output voltage and low energy density (batteries with a higher energy density can store larger amounts of energy, while batteries with a higher power density can release large amounts of energy more quickly).But researchers at Oregon State, the University of Central Florida and the University of Houston have designed an anode made up of a three-dimensional "zinc-M alloy" as the battery anode -- where M refers to manganese and other metals."The use of the alloy with its special nanostructure not only suppresses dendrite formation by controlling the surface reaction thermodynamics and the reaction kinetics, it also demonstrates super-high stability over thousands of cycles under harsh electrochemical conditions," Feng said. "The use of zinc can transfer twice as many charges than lithium, thus improving the energy density of the battery."We also tested our aqueous battery using seawater, instead of high purity deionized water, as the electrolyte," he added. "Our work shows the commercial potential for large-scale manufacturing of these batteries."Feng and Ph.D. student Maoyu Wang used X-ray absorption spectroscopy and imaging to track the atomic and chemical changes of the anode in different operation stages, which confirmed how the 3D alloy was functioning in the battery."Our theoretical and experimental studies proved that the 3D alloy anode has unprecedented interfacial stability, achieved by a favorable diffusion channel of zinc on the alloy surface," Feng said. "The concept demonstrated in this collaborative work is likely to bring a paradigm shift in the design of high-performance alloy anodes for aqueous and non-aqueous batteries, revolutionizing the battery industry."The National Science Foundation supported this research.
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Environment
| 2,021 |
January 11, 2021
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https://www.sciencedaily.com/releases/2021/01/210109152416.htm
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Engineering and biology researchers collaborate to aid coral reef restoration
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Florida's threatened coral reefs have a more than $4 billion annual economic impact on the state's economy, and University of Central Florida researchers are zeroing in on one factor that could be limiting their survival -- coral skeleton strength.
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In a new study published in the journal The researchers subjected coral skeletons to higher stresses than those caused by ocean waves, says Mahmoud Omer, a doctoral student in UCF's Department of Mechanical and Aerospace Engineering and study co-author. "Under normal wave and tide regimes, a staghorn coral's skeleton will resist the physical forces exerted by the ocean waves. However, anthropogenic stressors such as harmful sunscreen ingredients, elevated ocean temperature, pollution and ocean acidification will weaken the coral skeleton and reduce its longevity."Florida's coral reefs generate billions of dollars in local income, provide more than 70,000 jobs, protect the state's shorelines from storms and hurricanes, and support a diverse ecosystem of marine organisms, according to the U.S. National Oceanic and Atmospheric Administration.The study uncovered a unique safety feature of the staghorn coral skeleton: Its porous design keeps the coral from being instantly crushed by an impact.When the UCF engineers subjected skeleton samples to increasing stress, pores relieved the applied load and temporarily stalled further cracking and structural failure. The pores would "pop-in" and absorb some of the applied mechanical energy, thus preventing catastrophic failure. Although this ability has been shown in other coral species, this is the first time it's been demonstrated in staghorn coral."For the first time, we used the tools of mechanical engineering to closely examine the skeletons of a critically endangered coral raised in a coral nursery," says John Fauth, an associate professor in UCF's Department of Biology. "We now know more about the structure and mechanical performance of the staghorn coral skeleton than any other coral in the world. We can apply this knowledge to understand why staghorn coral restoration may work in some areas, but where their skeletons may fail due to human and environmental challenges in others."The results provide baseline values that can be used to judge if nursery-reared staghorn coral have skeletons strong enough for the wild and to match them to areas with environmental conditions that best fit their skeleton strength.Staghorn coral gets its name from the antler-like shape of its branches, which create an intricate underwater habitat for fish and reef organisms. It primarily is found in shallow waters around the Florida Keys, Puerto Rico, the U.S. Virgin Islands, and other Caribbean islands but has declined by more than 97 percent since the 1980s.Although restoration efforts using transplanted, nursery-reared coral are underway, scientists continue working to increase their success rate.Understanding coral skeleton structures also could inform development of skeletal structure replacements for humans, says Nina Orlovskaya, an associate professor in UCF's Department of Mechanical and Aerospace Engineering. "Our findings are of high importance for development of novel and superior biostructures, which can be used as bone graft substitutes," Orlovskaya says. "Coral skeleton structures could be either chemically converted or 3D printed into bio-compatible calcium phosphate ceramics that one day might be directly used to regenerate bones in humans."In addition to compression tests, the researchers analyzed mechanical properties and spectral and fluidic behavior. The spectral analysis used Raman microscopy, which allowed the researchers to map the effects of compression at the microscopic level in the coral skeleton.Fluidic behavior analysis revealed that vortices formed around the coral colony helped it to capture food and transport respiratory gases and wastes.The coral skeletons studied were from Nova Southeastern University's coral nursery, about one mile off the coast of Ft. Lauderdale, near Broward County, Florida. The corals were deceased and were from colonies that failed or were knocked loose during a storm.Study co-authors also included Alejandro Carrasco-Pena, a graduate of UCF's mechanical engineering doctoral program; Bridget Masa, a graduate of UCF's mechanical engineering bachelor program; Zachary Shepard, a graduate of UCF's mechanical engineering bachelor program; Tyler Scofield, a graduate of UCF's mechanical engineering master's and bachelor program; Samik Bhattacharya, an assistant professor in UCF's Department of Mechanical and Aerospace Engineering; Boyce E. Collins, a mechanical and chemical engineering scientist at North Carolina A&T State University; Sergey N. Yarmolenko, a senior research scientist at North Carolina A&T State University; Jagannathan Sankar, a distinguished university professor at North Carolina A&T State University; Ghatu Subhash, Ebaugh Professor in the Department of Mechanical and Aerospace Engineering at the University of Florida; and David S. Gilliam, an associate professor with Nova Southeastern University.The research was funded in part by the National Science Foundation and the U.S. Environmental Protection Agency.Orlovskaya obtained her doctorate in materials science from the Institute for Problems of Materials Science at the Ukrainian National Academy of Sciences in Kyiv. She joined UCF in 2006.Fauth received his doctorate in zoology from Duke University and joined UCF in 2003.
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Environment
| 2,021 |
January 11, 2021
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https://www.sciencedaily.com/releases/2021/01/210111094304.htm
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Expanding the boundaries of CO2 fixation
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Photorespiration is a highly energy consuming process in plants that leads to the release of previously fixed CO
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All life is dependent on the fixation of COResearchers led by Tobias Erb from the Max Planck Institute for terrestrial Microbiology have developed a synthetic photorespiratory bypass that represents an alternative to natural photorespiration. In collaboration with the group of Arren Bar-Even (Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm), and within the EU-funded project Future Agriculture, the team has designed the so-called tartronyl-CoA (TaCo) pathway that is much shorter than natural photorespiration and requires only 5 instead of 11 enzymes. The perhaps greatest benefit of the TaCo pathway is that it fixes COBuilding the TaCo pathway was a scientific journey that has led the researchers from computational model through enzymatic engineering, microfluidic high-throughut screening, cryo-EM-technology towards the successful in vitro implementation of a new-to-nature metabolic connection that opens up new possibilities for COFor the TaCo pathway, initially a handful of enzymes was found that were able to catalyze the required reactions. However, they showed low catalytic efficiencies, meaning that they were quite slow compared to naturally occurring enzymes. The researchers aimed to boost especially the performance of the key enzyme of the TaCo pathway, glycolyl-CoA carboxylase (GCC), the catalyst that makes photorespiration carbon positive.As a groundwork for creating a synthetic glycolyl-CoA carboxylase (GCC) the researchers developed a molecular model of the enzyme. Different variants of the enzyme were created based on a naturally occurring propionyl-CoA carboxylase, which is usually involved in fatty acid metabolism, as a scaffold by exchanging amino acid residues. This rational design strategy led to a 50-fold improvement of the enzyme's catalytic efficiency with glycolyl-CoA.In order to push the enzyme's performance even further, the researchers teamed up with the group of Jean-Christophe Baret from the French National Centre for Scientific Research (CNRS, CRPP) Bordeaux, France, with whom they developed an ultrahigh-throughput microfluidic screen and screened thousands of synthetic variants. Within two rounds of subsequent microplate screenings, an enzyme variant was discovered that showed an even almost 900-fold increased catalytic efficiency with glycolyl-CoA. "With this catalytic efficiency, GCC is in the range of naturally occurring biotin-dependent carboxylases. This means we were able to engineer an enzyme from almost no activity towards glycolyl-CoA to very high activity, which is comparable to naturally evolved enzymes," Marieke Scheffen explains.Solving the molecular structure of this newly developed catalyst was achieved in yet another collaboration, with Jan and Sandra Schuller from the Max Planck Institute of Biochemistry, Martinsried (now SYNMIKRO in Marburg). The researchers applied cutting-edge cryogenic electron microscopy (cryo-EM) at an atomic resolution of 1.96 Å, thus pushing the limits of cryo-EM.Finally, the synthetic GCC enzyme proved functional in in vitro experiments in combination with the two other enzymes of the TaCo pathway, thus forming an applicable carbon fixation pathway. "The TaCo pathway is not only a promising alternative for photorespiration," says Group Leader Tobias Erb. "We could also show that it can be interfaced with other synthetic COThis opens up a range of scientific possibilities, for example towards the recycling of polyethylene terephthalate (PET). The TaCo pathway could be used to convert ethylene glycol (a monomer of PET) directly into glycerate, making it usable for the production of biomass or value-added compounds. The next step will be to advance the in vivo implementation, in order to harness the full potential of the newly developed pathway.
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Environment
| 2,021 |
January 8, 2021
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https://www.sciencedaily.com/releases/2021/01/210108142151.htm
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Key step taken toward cleaner, more sustainable production of hydrogen
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Efficiently mass-producing hydrogen from water is closer to becoming a reality thanks to Oregon State University College of Engineering researchers and collaborators at Cornell University and the Argonne National Laboratory.
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The scientists used advanced experimental tools to forge a clearer understanding of an electrochemical catalytic process that's cleaner and more sustainable than deriving hydrogen from natural gas.Findings were published today in Hydrogen is found in a wide range of compounds on Earth, most commonly combining with oxygen to make water, and it has many scientific, industrial and energy-related roles. It also occurs in the form of hydrocarbons, compounds consisting of hydrogen and carbon such as methane, the primary component of natural gas."The production of hydrogen is important for many aspects of our life, such as fuel cells for cars and the manufacture of many useful chemicals such as ammonia," said Oregon State's Zhenxing Feng, a chemical engineering professor who led the study. "It's also used in the refining of metals, for producing human-made materials such as plastics and for a range of other purposes."According to the Department of Energy, the United States produces most of its hydrogen from a methane source such as natural gas via a technique known as steam-methane reforming. The process involves subjecting methane to pressurized steam in the presence of a catalyst, creating a reaction that produces hydrogen and carbon monoxide, as well as a small amount of carbon dioxide.The next step is referred to as the water-gas shift reaction in which the carbon monoxide and steam are reacted via a different catalyst, making carbon dioxide and additional hydrogen. In the last step, pressure-swing adsorption, carbon dioxide and other impurities are removed, leaving behind pure hydrogen."Compared to natural gas reforming, the use of electricity from renewable sources to split water for hydrogen is cleaner and more sustainable," Feng said. "However, the efficiency of water-splitting is low, mainly due to the high overpotential -- the difference between the actual potential and the theoretical potential of an electrochemical reaction -- of one key half-reaction in the process, the oxygen evolution reaction or OER."A half-reaction is either of the two parts of a redox, or reduction-oxidation, reaction in which electrons are transferred between two reactants; reduction refers to gaining electrons, oxidation means losing electrons.The concept of half-reactions is often used to describe what goes on in an electrochemical cell, and half-reactions are commonly used as a way to balance redox reactions. Overpotential is the margin between the theoretical voltage and the actual voltage necessary to cause electrolysis -- a chemical reaction driven by the application of electric current."Electrocatalysts are critical to promoting the water-splitting reaction by lowering the overpotential, but developing high-performance electrocatalysts is far from straightforward," Feng said. "One of the major hurdles is the lack of information regarding the evolving structure of the electrocatalysts during the electrochemical operations. Understanding the structural and chemical evolution of the electrocatalyst during the OER is essential to developing high-quality electrocatalyst materials and, in turn, energy sustainability."Feng and collaborators used a set of advanced characterization tools to study the atomic structural evolution of a state-of-the art OER electrocatalyst, strontium iridate (SrIrO3), in acid electrolyte."We wanted to understand the origin of its record-high activity for the OER -- 1,000 times higher than the common commercial catalyst, iridium oxide," Feng said. "Using synchrotron-based X-ray facilities at Argonne and lab-based X-ray photoelectron spectroscopy at the Northwest Nanotechnology Infrastructure site at OSU, we observed the surface chemical and crystalline-to-amorphous transformation of SrIrO3 during the OER."The observations led to a deep understanding of what was going on behind strontium iridate's ability to work so well as a catalyst."Our detailed, atomic-scale finding explains how the active strontium iridate layer forms on strontium iridate and points to the critical role of the lattice oxygen activation and coupled ionic diffusion on the formation of the active OER units," he said.Feng added that the work provides insight into how applied potential facilitates the formation of the functional amorphous layers at the electrochemical interface and leads to possibilities for the design of better catalysts.
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Environment
| 2,021 |
January 8, 2021
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https://www.sciencedaily.com/releases/2021/01/210108142149.htm
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Bacteria can tell the time
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Humans have them, so do other animals and plants. Now research reveals that bacteria too have internal clocks that align with the 24-hour cycle of life on Earth.
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The research answers a long-standing biological question and could have implications for the timing of drug delivery, biotechnology, and how we develop timely solutions for crop protection.Biological clocks or circadian rhythms are exquisite internal timing mechanisms that are widespread across nature enabling living organisms to cope with the major changes that occur from day to night, even across seasons.Existing inside cells, these molecular rhythms use external cues such as daylight and temperature to synchronise biological clocks to their environment. It is why we experience the jarring effects of jet lag as our internal clocks are temporarily mismatched before aligning to the new cycle of light and dark at our travel destination.A growing body of research in the past two decades has demonstrated the importance of these molecular metronomes to essential processes, for example sleep and cognitive functioning in humans, and water regulation and photosynthesis in plants.Although bacteria represent 12% biomass of the planet and are important for health, ecology, and industrial biotechnology, little is known of their 24hr biological clocks.Previous studies have shown that photosynthetic bacteria which require light to make energy have biological clocks.But free-living non photosynthetic bacteria have remained a mystery in this regard.In this international study researchers detected free running circadian rhythms in the non-photosynthetic soil bacterium Bacillus subtilis.The team applied a technique called luciferase reporting, which involves adding an enzyme that produces bioluminescence that allows researchers to visualise how active a gene is inside an organism.They focused on two genes: firstly, a gene called ytvA which encodes a blue light photoreceptor and secondly an enzyme called KinC that is involved in inducing formation of biofilms and spores in the bacterium.They observed the levels of the genes in constant dark in comparison to cycles of 12 hours of light and 12 hours of dark. They found that the pattern of ytvA levels were adjusted to the light and dark cycle, with levels increasing during the dark and decreasing in the light. A cycle was still observed in constant darkness.Researchers observed how it took several days for a stable pattern to appear and that the pattern could be reversed if the conditions were inverted. These two observations are common features of circadian rhythms and their ability to "entrain" to environmental cues.They carried out similar experiments using daily temperature changes; for example, increasing the length or strength of the daily cycle, and found the rhythms of ytvA and kinC adjusted in a way consistent with circadian rhythms, and not just simply switching on and off in response to the temperature."We've found for the first time that non-photosynthetic bacteria can tell the time," says lead author Professor Martha Merrow, of LMU (Ludwig Maximilians University) Munich. "They adapt their molecular workings to the time of day by reading the cycles in the light or in the temperature environment.""In addition to medical and ecological questions we wish to use bacteria as a model system to understand circadian clock mechanisms. The lab tools for this bacterium are outstanding and should allow us to make rapid progress," she added.This research could be used to help address such questions as: is the time of day of bacterial exposure important for infection? Can industrial biotechnological processes be optimised by taking the time of day into account? And is the time of day of anti-bacterial treatment important?"Our study opens doors to investigate circadian rhythms across bacteria. Now that we have established that bacteria can tell the time we need to find out the processes that cause these rhythms to occur and understand why having a rhythm provides bacteria with an advantage," says author Dr Antony Dodd from the John Innes Centre.Professor Ákos Kovács, co-author from the Technical University of Denmark adds that "Bacillus subtilis is used in various applications from laundry detergent production to crop protection, besides recently exploiting as human and animal probiotics, thus engineering a biological clock in this bacterium will culminate in diverse biotechnological areas."
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Environment
| 2,021 |
January 6, 2021
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https://www.sciencedaily.com/releases/2021/01/210106095316.htm
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First global study shows uneven urbanization among large cities in the last two decades
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The world has experienced dramatic urbanization in recent decades. According to the latest report from the United Nations (UN), the global population in 2018 was 7.6 billion and the urban population was 4.2 billion. By 2050, the global population is expected to soar to 9.7 billion, with 68% of the population living in urban areas. (Note 1)
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In the first-ever study on the characteristics of urbanization in large cities around the world, researchers at the Department of Civil Engineering of the University of Hong Kong (HKU) analyzed cities' urban built-up areas (BUAs) expansion, population growth and greening BUA changes, and revealed a hugely uneven pace of urbanization in those cities in the last two decades. They warn against major challenges posed to sustainable development if the urban problems are not dealt with in a timely manner. The findings have been published in Nature Communication.The study, conducted by Professor CHEN Ji at the Civil Engineering Department of the Faculty of Engineering, HKU, in collaboration with the Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, and National Supercomputing Center in Shenzhen, analysed the development of 841 large cities throughout the world with BUAs of over 100 km2 (Note 2) based on MODIS satellite data from 2001 to 2018 obtained under the International Geosphere-Biosphere Programme.Breakdown of the 841 large cities by country income-levelsThe findings revealed unevenness between built-up areas expansion (BUAE), which reflects the pace of infrastructure development, and urban population growth among the cities; and a widening gap between rapid urban population growth and slow urban greening, represented by features including new parks, green spaces and green roofs.Cities in the upper-middle-income countries demonstrated the highest BUA expansion, which was more than three times that of high-income countries. Urban expansion and urban population growth in high-income countries remained the lowest. Cities in the low-income and lower-middle-income countries had the highest urban population growth on average, but were substantially lagging behind in BUA expansion and infrastructure development, resulting in serious urban problems such as slums and crowding.The findings also revealed rapid urbanization of large cities in China in the last two decades. The country had undergone the biggest urban expansion in the period, between 2001 and 2018, its BUA increase accounted for 47.5% of the total expansion in the world. In 2018, the country has 19% of the total BUA of large cities in the world."Due to the rapid economic growth in the study period, China invested a large amount of resources into infrastructure construction for advancing the urban living environment. Its progress in greening has been impressive, benefitting at least 108 million city dwellers, accounting for 32% of the total greening at BUAs in the large cities over the world." Professor Chen said.Of the 841 cities studied, 325 showed significant greening with more than 10% of greening BUAs. Among them 101 are located in China. The largest greening BUAs are Pearl River Delta (PRD)(Note 3), Tokyo, Yangtze River Delta (YRD, Note 4), Miami, Beijing, Chicago, Seoul, Tianjin, Sao Paulo, and Osaka. In 2018, cities in the highest quarter of greenness range accommodated only 12% of the total city population; about 69% of the total population lived in areas with a lower greenness."China will reach carbon emission peak before 2030 and carbon neutrality by 2060, and large cities with a significant greening trend play an important role in neutralizing carbon emission and mitigating the impact of global climate change in urban areas. For the majority of the developing countries, understanding the uneven urbanization in the past decades can provide scientific references for urban management, helping to strike a balance between urbanization, population growth and environmental changes." Professor Chen said."Our research provides a low-cost method for monitoring sustainable urban development globally, and the quantitative findings contribute to a better understanding of how to achieve rational urbanization and sustainable development in various cities. The findings also serve as a warning that continuing and rapid urban development without proper and long-term planning can be detrimental and the urgent need is to strengthen urban planning and governance, especially in developing and least developed countries." Professor Chen added.Note 1: United Nations. World Urbanization Prospects: The 2018 Revision online edn (United Nations, 2018). Note 2: For reference, Hong Kong Island has an area of 78.64 kmNote 3: Pearl River Delta (PRD) is taken as a 'mega' city in the study comprising a cluster of cities including Guangzhou, Shenzhen, Dongguan, Foshan and Zhongshan Note 4: Yangtze River Delta includes cities of Shanghai, Suzhou, Wuxi and Changzhou
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Environment
| 2,021 |
January 5, 2021
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https://www.sciencedaily.com/releases/2021/01/210105104839.htm
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On the road to invisible solar panels: How tomorrow's windows will generate electricity
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Five years after the Paris climate agreement, all eyes are on the world's progress on the road to a carbon-free future. A crucial part of this goal involves the energy transition from fossil fuels to renewable sources, such as sun, water, wind and wave energy. Among those, solar energy has always held the highest hope in the scientific community, as the most reliable and abundant energy source on Earth. In recent decades, solar cells have become cheaper, more efficient, and environment friendly. However, current solar cells tend to be opaque, which prevents their wider use and integration into everyday materials, constrained to being lined up on roofs and in remote solar farms.
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But what if next-generation solar panels could be integrated to windows, buildings, or even mobile phone screens? That is the hope of Professor Joondong Kim from the Department of Electrical Engineering at Incheon National University, Korea. In a recent study published in The idea of transparent solar cells is well known, but this novel application where scientists have been able to translate this idea into practice is a crucial new finding. At present, the materials making the solar cell opaque are the semiconductor layers, those responsible for capturing light and translating it into an electrical current. Hence, Prof. Kim and his colleagues looked at two potential semiconductor materials, identified by previous researchers for their desirable properties.The first is titanium dioxide (TiOThe solar cell prepared by the researchers was composed of a glass substrate and a metal oxide electrode, on top of which they deposited thin layers of the semiconductors (TiOTheir findings were encouraging; with a power conversion efficiency of 2.1%, the cell's performance was quite good, given that it targets only a small part of the light spectrum. The cell was also highly responsive and worked in low light conditions. Furthermore, more than 57% of visible light was transmitted through the cell's layers, giving the cell this transparent aspect. In the final part of their experiment, the researchers demonstrated how their device could be used to power a small motor. "While this innovative solar cell is still very much in its infancy, our results strongly suggest that further improvement is possible for transparent photovoltaics by optimizing the cell's optical and electrical properties," suggests Prof. Kim.Now that they have demonstrated the practicality of a transparent solar cell, they hope to further improve its efficiency in the near future. Only further research can tell whether they will indeed become a reality, but for all intents and purposes, this new technology opens a -- quite literal -- window into the future of clean energy.
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Environment
| 2,021 |
January 5, 2021
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https://www.sciencedaily.com/releases/2021/01/210105095638.htm
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Using solar energy and agriculture to limit climate change, assist rural communities
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Co-developing land for both solar photovoltaic power and agriculture could provide 20% of total electricity generation in the United States with an investment of less than 1% of the annual U.S. budget, a new paper by Oregon State University researchers found.
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Wide-scale installation of agrivoltaic systems could lead to an annual reduction of 330,000 tons of carbon dioxide emissions in the U.S -- the equivalent of 75,000 cars off the road per year -- and the creation of more than 100,000 jobs in rural communities, while minimally impacting crop yield, the researchers say."Agrivoltaics provide a rare chance for true synergy: more food, more energy, lower water demand, lower carbon emissions, and more prosperous rural communities," said Chad Higgins, an associate professor in Oregon State's College of Agricultural Sciences and the senior author of the paper published in the journal Agrivoltaics also align with the goals of the Green New Deal, a package of federal legislation that seeks to address climate change and economic inequalities, Higgins said."Rural America, agriculture in particular, can be the solution to many of our concerns, whether it be renewable energy, mitigating climate change impacts, sustainable food or good water resource management," Higgins said. "That connection is untapped mostly because there hasn't been sufficient investment in those communities."What we propose in this paper is all possible. It's technically possible. It's politically possible. And it would make money after the initial investment. That's the takeaway -- that we should take a hard look at agriculture as a solution to problems rather than a cause of problems."The analysis outlined in the paper prepares Higgins for the next phase of his agrivoltaics research, which includes the installation of a fully functional solar farm designed to prioritize agricultural activities on five acres of Oregon State's North Willamette Research and Extension Station in Aurora, Oregon, 20 miles south of Portland.The next phase aims to demonstrate to the agricultural community and potential future funders how Higgins's findings can be applied in real world agricultural systems to encourage early adoption. Ground is expected to be broken in May 2021 with production expected to start in 2022.In the Sustainability paper, Higgins and his co-author, Kyle Proctor, a doctoral student in his lab, find that an area about the size of Maryland would be needed for agrivoltaics to meet 20% of U.S. electricity generation. That's about 13,000 square miles, or 1% of current U.S. farmland.The cost of the agrivoltaic arrays would be $1.12 trillion over a 35-year project life. The researchers believe that the private sector would invest in the bulk of the construction costs with the federal government contributing with rebates and other incentives.Using money generated from the electricity the arrays produce, the researchers estimate it would take about 17 years to payback the $1.12 trillion. After the projected 35-year lifespan of the project, the researchers estimate the arrays would produce $35.7 billion in revenue.Installation of the arrays would create the equivalent of 117,000 jobs lasting 20 years, with 40% being sustainable positions for operating and maintaining the arrays, the researchers say.Higgins comes at this project with an eclectic background. He went through a self-described engineering degree collection phase and has published papers on everything from enzyme reaction kinetics to snow physics to turbulence theory.The broad background came in handy one day in 2013 while he was strolling his "thinking walk path" on the Oregon State campus. He noticed greener pasture under recently installed solar arrays. Drawing on his background studying water, agriculture, renewable energy, mechanical and civil engineering, he started thinking about agrivoltaics research.His initial research focused on the impact solar arrays had on the crops planted around them. That research, along with work by other scientists, has shown that crop yield is dependent on the type of crop, but in the end, when the value of the electricity generated by the solar panels is included, there is an economic net benefit from the agrivoltaic systems.Looking to the future, Higgins believes the wide-scale installation of agrivoltaic systems opens the door for other technologies. The surplus energy generated by the solar arrays could be used to power electric tractors or to generate fertilizer on a farm. Inexpensive sensors could be installed on the solar panel platforms to support artificial intelligence-based decisions to improve agricultural productivity."Once we have infrastructure, once we have energy, we are ready to tackle so many more big problems," Higgins said.
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Environment
| 2,021 |
January 4, 2021
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https://www.sciencedaily.com/releases/2021/01/210104170059.htm
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Scientists develop new approach to understanding massive volcanic eruptions
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A geosciences team led by the University of South Florida (USF) has developed a new way to reconstruct the sizes of volcanic eruptions that occurred thousands of years ago, creating a first-of-its kind tool that can aid scientists in understanding past explosive eruptions that shaped the earth and improve the way of estimating hazards of future eruptions.
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The advanced numerical model the USF team developed allows scientists to reconstruct eruption rates through time by estimating the dimensions of the umbrella clouds that contribute to the accumulation of vast deposits of volcanic ash. The research is published in the new edition of the Nature Journal, The research, which was used to decipher the 2,500-year-old eruption of a volcano in Ecuador, was led by USF doctoral candidate Robert Constantinescu in collaboration with USF colleagues Research Associate Laura Connor, Professor Chuck Connor, Associate Professor Sylvain Charbonnier, doctoral alum Alain Volentik and other members of an international team. USF's Volcanology Group is one of the world's leading centers of volcano science and hazard assessment.When large explosive eruptions occur, they form laterally spreading umbrella clouds into the stratosphere, facilitating the transport of fine-grained ash over hundreds of miles that settles and covers large swaths of land.Current technology allows scientists to observe ash clouds. However, past eruptions are characterized based on the geological interpretation of their tephra deposits -- the pieces and fragments of rock ejected into the air by an erupting volcano. By estimating the erupted volume and mass, plume height, umbrella cloud dimensions and other characteristics, the scientists are able to understand and characterize the volcanic eruptions, therefore improving the forecast of future events.Using a series of field techniques combined with statistical and numerical modeling, volcanologists extract information from the deposits in order to characterize and classify an eruption on one of the most commonly used scales, the Volcanic Explosivity Index (VEI). Until now, the most sought-after information is the eruption column height and the total erupted mass or volume, Constantinescu said.But over time, deposits erode and can provide an uncertain picture of older eruptions. Also, current models have been limited in that they assume all volcanic eruptions created mostly vertical plumes, Constantinescu said, and don't account for large explosive eruptions that form laterally spreading umbrella ash clouds.The USF team's work shows that it is the dimensions of the umbrella clouds that is the telling factor in reconstructing past large explosive eruptions."The better we can reconstruct the nature of past eruptions from deposit data, the better we can anticipate potential hazards associated with future explosive eruptions," the team wrote in the new journal article.The researchers propose updating the VEI scale with the umbrella cloud dimensions, which can now be easily estimated using the mathematical models they've developed.The researchers applied their model to the tephra deposit of the eruption of Pululagua, a now dormant volcano about 50 miles north of the capital city of Quito. Ecuador is considered one of the world's most hazardous countries for volcanoes. The volcano last erupted an estimated 2,500 years ago and the area is now a geobotanical reserve renowned for its biodiversity and lush green landscape.There are about 1,500 potentially active volcanoes worldwide, in addition to those that lurk beneath the world's oceans. In 2020, there were at least 67 confirmed eruptions from 63 different volcanoes, according to the Smithsonian Institution Global Volcanism Program. "If in modern times the umbrella clouds of large eruptions are easily observed, we now have the ability to estimate the umbrella clouds of past eruptions," Constantinescu said. "Our numerical model enables us to better characterize past volcanic eruptions and inform models for future hazard assessment."The USF team was joined in the research by Aurelian Hopulele-Gligor of Cluj-Napoca, Romania; Costanza Bonadonna of the University of Geneva; and Jan M. Lindsay of the University of Auckland. The research was funded in part by the National Science Foundation.
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Environment
| 2,021 |
January 4, 2021
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https://www.sciencedaily.com/releases/2021/01/210104131932.htm
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Fires, flooding before settlement may have formed the Amazon's rare patches of fertility
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Phosphorus, calcium and charcoal in spotty patches of fertile soil in the Amazon rainforest suggest that natural processes such as fires and river flooding, not the ingenuity of indigenous populations, created rare sites suitable for agriculture, according to new research.
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The presence of pre-Columbian artifacts and signs of plant domestication uncovered in the region's fertile soil, commonly called Amazonian dark earth, had been thought to mean that agricultural practices, including controlled burning, by indigenous people had boosted soil nutrients.However, radiocarbon dating of soil at an extensively studied 210-hectare basin near the confluence of the Solimoes and Negro rivers in northwest Brazil tell a different story, said Lucas Silva, a professor of environmental studies at the University of Oregon who led the project.In a paper that published Jan. 4 in Those levels, Silva said, correlate spatially with 16 trace elements that indicate that fertility did not form in place. Combined with other elements in the soil and isotopic ratios of neodymium and strontium, the researchers concluded that pre-settlement river flooding likely delivered nutrients and charcoal from upstream."We analyzed carbon and nutrient pools in light of the local anthropological context to estimate the chronology of management and the population density needed to attain the observed gain in Amazonian dark earth fertility compared to the surrounding landscape," Silva said.Much of the Amazon contains highly weathered oxisols and ultisols, tropical soil types with high acidity and low nutrient levels. Archaeological artifacts have been found in charcoal-rich soil that began forming about 7,600 years ago, about 1,000 years before indigenous people transitioned from nomadic to sedentary populations in patches of land in the notoriously nutrient-poor Amazon environment, the researchers noted."Our results show that large sedentary populations would have had to manage soils thousands of years prior to the emergence of agriculture in the region or, more likely, that indigenous peoples used their knowledge to identify and preferentially settle areas of exceptionally high fertility before the onset of soil management in central Amazonia," he said.Researchers have long theorized that Amazonian dark earth had been formed by controlled burning of forest biomass. That view, Silva said, fueled an entire industry of charcoal production from biosolids, such as biochar, in which such soils are considered a model for sustainable agriculture.Charcoal and nutrient accumulation, the researchers argue, match that found in sedimentary deposits that can be traced to open vegetation fires upstream from rivers that flooded.Records of soil content and past monsoon intensity, the researchers said, indicate a climate-driven shift in river dynamics after a long dry period between 8,000 and 4,000 years ago. That shift to flooding, they noted, would have reduced fire disturbance, increased regional tree coverage and "could have caused divergent patterns of carbon and nutrient accumulation in flooded versus non-flooded areas," consistent with the minerals in the dark earth at the research site.Many areas of central Amazonia today are associated with sediment deposits that reflect flood regimes that were either deactivated during the Holocene or are presently in the process of deactivation, when sedimentary deposits become suitable habitats for grasslands within the rainforest, the researchers wrote."Our findings underscore the need for a broader view of landscape evolution as a path towards understanding the formation of Amazonian dark earths and redirecting applications for sustainable land use and conservation," said Silva, who has visited and gathered samples from the site since 2009 when he was a doctoral student."If corroborated elsewhere," he said, "our hypothesis would transform our understanding of human influence in Amazonia, opening new frontiers for the sustainable use of tropical landscapes going forward."
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Environment
| 2,021 |
December 31, 2020
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https://www.sciencedaily.com/releases/2020/12/201231141511.htm
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Desalination breakthrough could lead to cheaper water filtration
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Producing clean water at a lower cost could be on the horizon after researchers from The University of Texas at Austin and Penn State solved a complex problem that has baffled scientists for decades, until now.
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Desalination membranes remove salt and other chemicals from water, a process critical to the health of society, cleaning billions of gallons of water for agriculture, energy production and drinking. The idea seems simple -- push salty water through and clean water comes out the other side -- but it contains complex intricacies that scientists are still trying to understand.The research team, in partnership with DuPont Water Solutions, solved an important aspect of this mystery, opening the door to reduce costs of clean water production. The researchers determined desalination membranes are inconsistent in density and mass distribution, which can hold back their performance. Uniform density at the nanoscale is the key to increasing how much clean water these membranes can create."Reverse osmosis membranes are widely used for cleaning water, but there's still a lot we don't know about them," said Manish Kumar, an associate professor in the Department of Civil, Architectural and Environmental Engineering at UT Austin, who co-led the research. "We couldn't really say how water moves through them, so all the improvements over the past 40 years have essentially been done in the dark."The findings were published today in The paper documents an increase in efficiency in the membranes tested by 30%-40%, meaning they can clean more water while using significantly less energy. That could lead to increased access to clean water and lower water bills for individual homes and large users alike.Reverse osmosis membranes work by applying pressure to the salty feed solution on one side. The minerals stay there while the water passes through. Although more efficient than non-membrane desalination processes, it still takes a large amount of energy, the researchers said, and improving the efficiency of the membranes could reduce that burden."Fresh water management is becoming a crucial challenge throughout the world," said Enrique Gomez, a professor of chemical engineering at Penn State who co-led the research. "Shortages, droughts -- with increasing severe weather patterns, it is expected this problem will become even more significant. It's critically important to have clean water availability, especially in low-resource areas."The National Science Foundation and DuPont, which makes numerous desalination products, funded the research. The seeds were planted when DuPont researchers found that thicker membranes were actually proving to be more permeable. This came as a surprise because the conventional knowledge was that thickness reduces how much water could flow through the membranes.The team connected with Dow Water Solutions, which is now a part of DuPont, in 2015 at a "water summit" Kumar organized, and they were eager to solve this mystery. The research team, which also includes researchers from Iowa State University, developed 3D reconstructions of the nanoscale membrane structure using state-of-the-art electron microscopes at the Materials Characterization Lab of Penn State. They modeled the path water takes through these membranes to predict how efficiently water could be cleaned based on structure. Greg Foss of the Texas Advanced Computing Center helped visualize these simulations, and most of the calculations were performed on Stampede2, TACC's supercomputer.
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Environment
| 2,020 |
December 28, 2020
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https://www.sciencedaily.com/releases/2020/12/201228095236.htm
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New research makes strong case for restoring Hong Kong's lost oyster reefs
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New research produced jointly by The Swire Institute of Marine Science (SWIMS), Faculty of Science, The University of Hong Kong (HKU), and The Nature Conservancy (TNC), published recently in the scientific journal
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Hong Kong was once home to thriving shellfish reefs, but due to a combination of factors including over-exploitation, coastal reclamation and pollution, shellfish populations have declined drastically. Restoring oyster reefs along urbanized coastlines can mitigate some of the environmental problems typical of coastal development, such as damage from storm surge and loss of biodiversity."Globally, we have lost 85% of shellfish reefs, making it the most endangered marine habitat on earth," said Marine Thomas, Conservation Project Manager, for TNC in Hong Kong. "Most people associate oysters with food, but less well-known is that oysters create reef habitats that support coastal marine life. Only by restoring these lost habitats can we start to bring back some of the associated environmental benefits."A primary benefit that healthy oyster reefs contribute to coastal environments is their role as natural water purifiers: This new study found that, just 7 mEven more importantly, oyster reefs provide habitat and nursery grounds for many native species that are otherwise lost from our shores. Another recent SWIMS study conducted in partnership with TNC found that these reefs house six times more species than bare muddy shores. The research found over 80 species on intertidal muddy shores in Deep Bay, 95% of which were found in oyster reefs, and almost 60% of which were exclusively found in those reefs."A previous SWIMS study found that Hong Kong is home to approximately 6,000 marine species and 26% of all marine species in China. This new research adds to that list, as we've identified a small crab previously not seen in Hong Kong. This shows us just how under-studied these ecosystems are," said Dr Bayden D Russell, an Associate Director of SWIMS and Associate Professor in the Research Division for Ecology and Biodiversity, HKU.Another benefit of restored reefs is increased production of commercially and recreationally valuable fish and crabs.Further, demonstration of successful restoration in one of Asia's coastal mega-cities can also act as model, providing evidence for the environmental and societal benefits of ecological restoration within the region.In some parts of the world, oyster reef restoration has only been successful by transplanting juvenile oysters cultivated in hatcheries into the wild. However, this new research demonstrates that natural recruitment of oysters in Hong Kong is high, meaning that restoration could potentially be achieved without the need for hatchery-reared oysters."We were excited to find high natural recruitment levels which suggests that oyster reef restoration is possible without hatchery intervention," said Dr Russell. "We think that this recruitment is because traditional oyster farming in the Pearl River Delta has maintained populations of native oysters in the system in spite of the loss of oyster reefs and these farms could potentially act as a source of larvae."In assessing 10 sites where small remnant shellfish habitats are found in Hong Kong, the study also found that large oysters (beyond 1 year old) are very hard to find in the wild, due to on-going harvesting pressures."While we are excited by the biological feasibility of restoration, unfortunately the human aspect remains our biggest challenge to bring these habitats back at scale. Shellfish habitats are still severely under protected in Hong Kong, with very little public awareness of their ecological value. Wild harvesting is a huge problem -- as soon as oysters or mussels are big enough to eat, someone will harvest them. We are working with Government on gaining more protection and recognition for these important ecosystems and hope to include them in the next Hong Kong Biodiversity Strategy and Action Plan (BSAP)," said Ms Thomas.
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Environment
| 2,020 |
December 24, 2020
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https://www.sciencedaily.com/releases/2020/12/201224113122.htm
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Novel method reveals small microplastics throughout Japan's subtropical ocean
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Research conducted in the Light-Matter Interactions for Quantum Technologies Unit at the Okinawa Institute of Science and Technology Graduate University (OIST) has revealed the presence of small microplastics in the ocean surrounding Okinawa. The study was published in
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"There's been a considerable amount of research on larger plastic pieces in the ocean," said Christina Ripken, PhD student in the Unit and lead author of the paper. "But the smaller pieces, those that are less than 5mm in size, haven't been in the spotlight, so it was important to identify whether they're present and the impacts they might have on living organisms."Okinawa was an interesting place to carry out this study. A small, subtropical island in southern Japan, it is surrounded by fringing coral reefs, which means that the ocean around the beaches is reliant on surface water and wind. It has also been deemed a 'blue zone' -- a region whose residents are exceptionally long-lived. Therefore, the researchers thought it crucial to monitor ocean pollution as it may adversely affect these residents.In collaboration with the Okinawa Prefecture Government, Christina carried out the sampling in September 2018. Six sites were visited close to the island's shoreline. To look at a range of different areas, two of the sites were to the south of the island, two were around the center, and two to the north. In Naha, the capital of the Okinawa Prefecture, samples were taken from beside the industrial port and the airport. Naha has an estimated population of over 300,000 inhabitants, which represents a fourth of the total population of the island. In contrast, Cape Hedo, at the far north of the island, has a very low population and is considerably less urbanized.At each site, the surface water was trawled for one kilometer, allowing approximately 800 liters of water to be filtered and small particles to be removed. These particles were then analyzed in the lab at OIST.Christina worked with Dr. Domna Kotsifaki, staff scientist in the Light-Matter Interactions for Quantum Technologies Unit, who combined two techniques -- the optical tweezers technique and the micro-Raman technique -- to provide a novel way of analyzing the particles.The optical tweezers technique uses lasers to hold the particle in the liquid, while the micro-Raman technique identified the unique molecular fingerprint of each particle. This allowed the researchers to see exactly what was present, whether that be organic material, trace metal, or different plastics like polyethylene or polystyrene."This method is what sets the study apart from other research into marine microplastics," said Dr. Kotsifaki. "It meant that we didn't need to filter out the plastic first, so we could see if there was plastic embedded within organic material or if any trace metals were present and the concentration of the plastics in the sampled seawater."As can be expected, the researchers found that there was more plastic in the water to the south of the island than to the north. But somewhat surprisingly, they found that the plastic correlated more with where people were living rather than with particularly industrialized areas.Concerningly, they found plastic in all the samples.Over 75% of the plastics found in the samples were made from polyethylene, which the researchers theorized could come from broken fishing equipment, water bottle caps, household utensils, plastic bags, plastic containers, and packaging."In the fishing communities, at the ports and beaches where the fish are landed, workers use woven polymer sacks to store and transport items including fish," said Christina. "This is an example of how the small pieces of plastic might be leaching into the ocean."Another way is through plastic in road dust. Recent research found a high concentration of microplastics in dust samples taken from the roads of Okinawa's heavily urbanized areas, which have considerable amounts of vehicle traffic. Some of this road dust may now be found in the ocean around Okinawa."We found more plastic around the heavily urbanized area in the south of the island than around the industrialized center or the rural north, but everywhere we found plastic," said Christina. "Our method means that we have a clearer view on the prevalence of microplastics around Okinawa and this can lead to risk analysis and influence policy. We hope it will help boost the environmental research area."
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Environment
| 2,020 |
December 23, 2020
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https://www.sciencedaily.com/releases/2020/12/201223125739.htm
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Conifers can be green because of a photosynthetic short-cut
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How can conifers that are used, for example, as Christmas trees, keep their green needles over the boreal winter when most trees shed their leaves? Science has not provided a good answer to this question but now an international team of scientists, including researchers from Umeå University, has deciphered that a short-cut in the photosynthetic machinery allows the needles of pine trees to stay green. The study was published in the journal
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In winter, light energy is absorbed by the green chlorophyll molecules but cannot be utilized by the downstream reactions in the photosynthetic machinery as freezing temperatures stop most biochemical reactions. This is especially a problem in the early spring when temperatures can still be very low, but sunlight is already strong, and the excess light energy can damage the proteins of the photosynthetic machinery. The researchers showed that the photosynthetic apparatus is wired in a special way which allows pine needles to stay green all year long.Under normal conditions, the two photosystems, the two functional units where light energy is absorbed and converted into chemical energy, are kept apart from each other to prevent a short-cut and allow efficient photosynthesis. In winter, the structure of the thylakoid membrane, where the two photosystems are located, is reorganized which brings the two photosystems in physical contact. The researchers showed that photosystem II donates energy directly to photosystem I and this short-cut mode protects the green chlorophyll and the needles when conditions become harsh."We have followed several pine trees growing in Umeå in northern Sweden over three seasons," says Pushan Bag, PhD student at Umeå University, who has collected samples all around the year and made many of the analyses. "It was essential that we could work on needles "straight from outdoors" to prevent that they adjusted to the higher temperatures in the lab environment before we analysed them for example with electron microscopy which we used to visualize the structure of the thylakoid membrane."All plants have safety valves to deal with the excess light energy which is either dissipated as heat or as fluorescence light. However, only conifers seem to have such powerful valves that they can keep the photosynthetic apparatus intact over the extreme boreal winter. The research team combined biochemistry and ultrafast fluorescence analysis, a very sophisticated method that can resolve chlorophyll fluorescence light at a picosecond time scale. Like this, they could demonstrate how the pine needles deal with excess light energy to protect their sensitive photosynthetic apparatus from damage."We needed to adjust the equipment to study pine needles in cold temperatures in order to trap the unique mechanism," explains Volha Chukhutsina from Vrije Universiteit Amsterdam, who has performed much of the ultrafast fluorescence analysis. "We also tried spruce needles but they were hard to fit in a good way into the equipment."Alfred Holzwarth, who has developed the time-resolved fluorescence measurements adds: "The pine needles gave us the opportunity to study this shortcut mechanism -- also called spill-over -- as they really show an extreme adaptation."The study was done with pine trees, but the researchers believe that the mechanism is probably similar for other conifer species -- like the typical Christmas trees spruces and firs -- because their photosynthetic apparatus is similar."This remarkable adaptation not only enjoys us during Christmas but is in fact extremely important for mankind," says professor Stefan Jansson from Umeå University. "Hadn´t conifers been able to survive in extreme harsh winter climates vast areas in the northern hemisphere may not have been colonized as conifers provided firewood, housing and other necessities. Still today they form the basis of the economy in most of the circumpolar taiga region."
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Environment
| 2,020 |
December 22, 2020
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https://www.sciencedaily.com/releases/2020/12/201222132106.htm
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Extracting energy from manure to meet peak heating demands
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Cornell University is developing a system to extract energy from cattle manure to meet the campus's peak demands for heat in the winter months. In the
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The university is already involved in an initiative to develop renewable energy sources and services, with the goal of reducing its carbon footprint by 100% by 2035. These goals are proving difficult to achieve in cold regions, such as Ithaca, New York, where the university is located, since over six months of winter heating is needed for its buildings and laboratories.Heating needs are a significant portion of Cornell's energy usage, and a challenge occurs at peak heating times. The university is developing a geothermal project that provides heat from hot water extracted 3-4 kilometers underground. This will provide adequate base-level heating but would be economically unattractive to meet peak demand.To meet the need for more heat in the depths of winter, the investigators are proposing a system to convert cattle manure from the school's dairy farms, which house 600 cows, to methane and other products. The method employs a three-stage process, where the manure is first biologically digested with microbes to produce biogas, a mixture of carbon dioxide and methane.This is followed by a second stage that converts the digested manure into a type of biocrude oil plus a substance called hydrochar that makes a good soil amendment.The final stage combines the carbon dioxide generated in the first step with hydrogen gas produced by renewable electrolysis of lake water to biologically generate renewable natural gas, RNG. This final product can be injected into the natural gas grid for New York state, in much the same way electricity from wind turbines and solar panels is returned to the electrical grid."The proposed system will produce about 909 million liters of RNG per year," said author Nazih Kassem. "This can provide 97% of the total annual peak heating demand. The remainder can be met by purchasing natural gas, increasing Cornell's dairy herd size, or using campus eateries' food wastes for co-digestion. Adding 19 more dairy cows would result in enough RNG production to meet the average annual peak heating demand."The investigators' detailed economic analysis revealed the importance of state policies regarding the RNG price and other issues."If New York state were to adopt policies to create a carbon market and enable competitive RNG pricing, then the proposed biomass peak heating system would show profitability," Kassem said.
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Environment
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December 22, 2020
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https://www.sciencedaily.com/releases/2020/12/201222132022.htm
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Droughts, viruses and road networks: Trends that will impact our forests
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Earth's forests are indispensable for both humans and wildlife: they absorb CO2, provide food for large parts of the world's population and are home to all sorts of animals.
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However, forest conservation measures are lagging in many countries, says Laura Vang Rasmussen, an assistant professor at the University of Copenhagen's Department of Geosciences and Nature Management."It is critical for all countries -- especially those with poor economic conditions, to prioritize forests and have forest conservation plans. Without the adoption of conservation strategies, droughts and viral outbreaks could have severe consequences on forests and humans alike," she says.Rasmussen, along with fellow researchers from the University of Manchester, is behind a new Nature-study in which 24 experts from the around the world have ranked the most significant trends that will affect the world's forests over the coming decade.In Denmark, we have seen an increase in the number of summers with scant rainfall, and in the rest of the world -- particularly on the US West Coast -- droughts have been responsible for massive and devastating forest fires. The new study argues that this trend will continue:"When we lose forest, due to drought for example, the risk of spreading viruses like coronavirus increases. When forest fires disturb natural ecosystems, disease carrying animals such as bats or rats flee from their charred ecosystems into towns and villages. And, as we have seen with the coronavirus pandemic, viral outbreaks have enormous consequences on global health and economy," explains Rasmussen.More people wanting to move from rural areas into the cities can have both positive and negative consequences for the world's forests."It could be that the amount of forest increases as more and more farmers abandon their livelihoods in favour of higher wage urban jobs. This would allow forests room to grow. Conversely, we run the risk that ballooning urban populations will increase demand for marketable crops, which will result in more forests being cleared for agriculture," says Laura Vang Rasmussen.Furthermore, the planet's human population is projected to increase to roughly 8.5 billion by 2030. This will result in an increased demand for meat, cereals, vegetables, etc., meaning that more forests will need to be cleared to accommodate for fields and meat production farms and facilities.By 2050, global road networks are projected to expand by roughly 25 million kilometres.This is likely to have a positive effect on human mobility, allowing people to shuttle between cities with ease and more readily move and sell goods.However, the downside of road building is the inevitably of having to clear forestland for roadbed.Besides having to look after forests for the sake of the environment and wildlife, forest conservation also relates to poverty, concludes Laura Vang Rasmussen:"It is problematic that forest conservation, agriculture and poverty are seen as distinct from one another. Indeed, the three factors influence each other, as strategies to increase agricultural production can negatively impact forests. On the other hand, an increase in forested areas makes it more difficult for agriculture to produce enough food. As such, we hope that our research is able to contribute towards highlighting the complex dynamics between agricultural production, deforestation, poverty and food security."
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Environment
| 2,020 |
December 22, 2020
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https://www.sciencedaily.com/releases/2020/12/201222132021.htm
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It's electrifying! This is how Earth could be entirely powered by sustainable energy
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Can you imagine a world powered by 100% renewable electricity and fuels? It may seem fantasy, but a collaborative team of scientists has just shown this dream is theoretically possible -- if we can garner global buy-in.
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The newly published research, led by Professor James Ward from the University of South Australia and co-authored by a team including Luca Coscieme from Trinity College Dublin, explains how a renewable future is achievable.The study, published in the international journal, The fully renewable energy-powered future envisioned by the team would require a significant "electrification" of our energy mix and raises important questions about the potential conflict between land demands for renewable fuel production.Explaining the work in some detail, Luca Coscieme, Research Fellow in Trinity's School of Natural Sciences, said:"Firstly, the high fuel needs of today's high-income countries would have to be reduced as it would require an unsustainably vast amount of land to be covered with biomass plantations if we were to produce enough fuel to satisfy the same levels."Additionally, our research shows that we would need to radically 'electrify' the energy supply of such countries -- including Ireland -- with the assumption that these changes could supply 75% of society's final energy demands. We would also need to adopt technology in which electricity is used to convert atmospheric gases into synthetic fuels."We very much hope that the approach designed in this research will inform our vision of sustainable futures and also guide national planning by contextualising energy needs within the broader consumption patterns we see in other countries with energy and forest product consumption profiles that -- if adopted worldwide -- could theoretically be met by high-tech renewably derived fuels. Countries such as Argentina, Cyprus, Greece, Portugal and Spain are great examples in this regard."Even so, the success of this green ideal will be highly dependent on major future technological developments, in the efficiency of electrification and in producing and refining new synthetic fuels. Such a scenario is still likely to require the use of a substantial -- albeit hopefully sustainable -- fraction of the world's forest areas."
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Environment
| 2,020 |
December 21, 2020
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https://www.sciencedaily.com/releases/2020/12/201221173119.htm
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Light signal emitted during photosynthesis used to quickly screen crops
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An international effort called Realizing Increased Photosynthetic Efficiency (RIPE) aims to transform crops' ability to turn sunlight and carbon dioxide into higher yields. To achieve this, scientists are analyzing thousands of plants to find out what tweaks to the plant's structure or its cellular machinery could increase production. University of Illinois researchers have revealed a new approach to estimate the photosynthetic capacity of crops to pinpoint these top-performing traits and speed up the screening process, according to a new study in the
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"Photosynthesis is the entry point for carbon dioxide to become all the things that allow plants to grow, but measuring canopy photosynthesis is really difficult," said Carl Bernacchi, a Research Plant Physiologist for the U.S. Department of Agriculture, Agricultural Research Service, who is based at Illinois' Carl R. Woese Institute for Genomic Biology. "Most methods are time-consuming and only measure a single leaf when it's the function of all leaves on all plants that really matters in agriculture."Bernacchi's team uses two spectral instruments simultaneously -- a hyperspectral camera for scanning crops and a spectrometer used to record very detailed information about sunlight -- to quickly measure a signal called Solar Induced Fluorescence (SIF) that is emitted by plants when they become 'energy-excited' during photosynthesis.With this SIF signal, the team gains critical insights about photosynthesis that could ultimately lead to improving crop yields.They discovered that a key part of the SIF signal better correlates with photosynthetic capacity. This 'SIF yield' accounts for only a fraction of the energy emitted as SIF by plants to the energy captured by plants in total, but it carries important information."With this insight, we can use a couple of instruments in a synergistic way to make more accurate estimates, and we can make these tools and pipelines more accessible to people who are interested in advancing the translation of photosynthesis," said Peng Fu, a postdoctoral researcher who led this work at Illinois.In this study, they picked out specific bands of light that are known to be linked to SIF (and are already well understood physiologically) to better understand what hyperspectral data is actually needed to make these estimates.In the past, they relied on expensive hyperspectral cameras that captured thousands of bands of light. "However, this study suggests that much cheaper cameras could be used instead now that we know what bands of light are needed," said Matthew Siebers, a postdoctoral researcher at Illinois.These tools could speed up progress by orders of magnitude, said Katherine Meacham-Hensold, also a postdoctoral researcher at Illinois. "This technology is game-changing for researchers who are refining photosynthesis as a means to help realize the yields that we will need to feed humanity this century."Realizing Increased Photosynthetic Efficiency (RIPE) is an international research project that is improving photosynthesis to equip farmers worldwide with higher-yielding crops to ensure everyone has enough food to lead a healthy and productive life. RIPE is supported by the Bill & Melinda Gates Foundation, the U.S. Foundation for Food and Agriculture Research, and the U.K. Foreign, Commonwealth & Development Office, who are committed to ensuring Global Access and making the project's technologies available to the farmers who need them the most.
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Environment
| 2,020 |
December 21, 2020
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https://www.sciencedaily.com/releases/2020/12/201221121825.htm
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Current food production systems could mean far-reaching habitat loss
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The global food system could drive rapid and widespread biodiversity loss if not changed, new research has found.
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Findings published in The international research team was led by the University of Leeds and the University of Oxford.Dr David Williams, from Leeds' School of Earth and Environment, and the Sustainability Research Institute, is a lead author of the paper.He said: "We estimated how agricultural expansion to feed an increasingly wealthy global population is likely to affect about 20,000 species of mammals, birds, and amphibians."Our research suggests that without big changes to food systems, millions of square kilometres of natural habitats could be lost by 2050."Nearly 1,300 species are likely to lose at least a quarter of their remaining habitat, and hundreds could lose at least half. This makes them far more likely to go extinct."Ultimately, we need to change what we eat and how it is produced if we're going to save wildlife on a global scale. We need to alter both our diets and food production methods."The study estimated how food systems would affect biodiversity at a finer spatial scale than previous research (2.25 kmIt did so by linking projections of how much agricultural land each country will need with a new model that estimates where agricultural expansion and abandonment are most likely to occur.By looking at whether individual animal species can survive in farmland or not, the researchers could then estimate changes in habitat, finding that losses were particularly severe in sub-Saharan Africa and in parts of Central and South America.Many of the species that are likely to be most affected are not listed as threatened with extinction, and so are unlikely to be currently targeted by conservationists.Dr Michael Clark, from Oxford Martin School and Nuffield Department of Population Health, University of Oxford, is also a lead author on the paper.He said: "As international biodiversity targets are set to be updated in 2021, these results highlight the importance of proactive efforts to safeguard biodiversity by reducing demand for agricultural land."Discussions on slowing and reversing biodiversity often focus on conventional conservation actions, such as establishing new protected areas or species-specific legislation for threatened species. These are absolutely needed, and have been effective at conserving biodiversity."However, our research emphasises the importance of also reducing the ultimate stresses to biodiversity -- such as agricultural expansion."The good news is that if we make ambitious changes to the food system, then we can prevent almost all these habitat losses."The study examined the potential impact of making these ambitious changes, modelling whether transitions to healthy diets, reductions in food loss and waste, increases in crop yields, and international land-use planning could reduce future biodiversity losses.This approach enables policy makers and conservationist to identify which changes are likely to have the largest benefit in their country or region.For example, raising agricultural yields would likely bring huge benefits to biodiversity in Sub-Saharan Africa, but do very little in North America where yields are already high.In contrast, shifting to healthier diets would have big benefits in North America, but is less likely to have a large benefit in regions where meat consumption is low and food insecurity is high.Dr Clark added: "Importantly, we need to do all of these things. No one approach is sufficient on its own."But, with global coordination and rapid action, it should be possible to provide healthy diets for the global population in 2050 without major habitat losses."
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Environment
| 2,020 |
December 21, 2020
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https://www.sciencedaily.com/releases/2020/12/201221121737.htm
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New energy conversion layer for biosolar cells
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A research team from the Ruhr-Universität Bochum (RUB), together with colleagues from Lisbon, has produced a semi-artificial electrode that could convert light energy into other forms of energy in biosolar cells. The technique is based on the photosynthesis protein Photosystem I from cyanobacteria. The group showed that they could couple their system with an enzyme that used the converted light energy to produce hydrogen. The results were published online in advance in October 2020 in the journal
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For the work, the RUB group consisting of Panpan Wang, Dr. Fangyuan Zhao, Dr. Julian Szczesny, Dr. Adrian Ruff, Dr. Felipe Conzuelo and Professor Wolfgang Schuhmann from the Center for Electrochemistry cooperated with the team consisting of Anna Frank, Professor Marc Nowaczyk and Professor Matthias Rögner from the Chair of Biochemistry of Plants as well as colleagues from the Universidade Nova de Lisboa.Photosystem I is part of the photosynthesis machinery in cyanobacteria and plants. With the help of light energy, it can separate charges and thus generate high-energy electrons that can be transferred to other molecules, for example to protons for the production of hydrogen.In earlier work, the Bochum scientists had already used the light-collecting protein complex photosystem I to design electrodes for biosolar cells. For this purpose, they covered an electrode with a photosystem I monolayer. In such monolayers, the photosystems are not stacked on top of each other, but lie side by side in the same plane. Photosystem I, however, usually occurs as a trimer, i.e. three photosystems are always linked together. Since the trimers cannot be packed close together, holes appear in the monolayer, which can lead to short circuits. This impairs the performance of the system. It was precisely this problem that the scientists solved in the present work.In the cyanobacterium To show what the technique could be in principle used for, the scientists coupled it to a hydrogenase enzyme that produced hydrogen using electrons provided by the photosystem. "Future work will be directed toward even more efficient coupling between the photosystem monolayer and the integrated biocatalysts to realize practical biosystems for solar energy conversion," the authors preview in their publication.
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Environment
| 2,020 |
December 21, 2020
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https://www.sciencedaily.com/releases/2020/12/201221121717.htm
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How Colorado potato beetles beat pesticides
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The Colorado potato beetle is a notorious pest -- and a kind of unstoppable genius.
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The modern pesticide era began in the 1860s when Midwest farmers started killing these beetles by spraying them with a paint color called Paris Green that contained copper arsenate. The beetles soon overcame that poison as well as lead arsenate, mercury DDT, and dieldrin -- and over fifty other pesticides. At first, with any new chemical, many beetles are killed -- but none of them last for long. The beetles develop resistance, usually within a few years, and continue merrily chomping their way through vast acres of potatoes in farms and gardens around the world.Scientists have a poor understanding of how this creature turns this trick. Current evolutionary theory, focused on DNA, falls short of explaining the rapid development of pesticide resistance. While the beetle shows a lot of genetic variation, new DNA mutations probably do not show up frequently enough to let them evolve resistance to so many types of pesticides, so fast -- over and over.But now a first-of-its-kind study moves dramatically closer to an explanation.A team of researchers, led by Prof. Yolanda Chen at the University of Vermont, shows that even small doses of the neonicotinoid pesticide, imidacloprid, can alter how the beetle manages its DNA. To fend off the pesticides, the new research suggests, the beetle may not need to change its underlying genetic code. Instead, the team found that beetles respond by altering the regulation of their DNA, turning certain genes on or off in a process called "DNA methylation." These so-called epigenetic changes allow beetles to quickly ramp up biological defense mechanisms -- perhaps putting into overdrive already-existing genes that allow the beetle to tolerate a broad range of toxins found in potato plants.A flush of enzymes or faster rate of excretion may let the insect stymie each new pesticide with the same ancient biochemical tools that it uses to overcome natural plant defenses -- rather than relying on the ponderous evolutionary process of random mutations appearing in key genes, that would slowly cause a pesticide to become less effective.Most important, the new study shows that these changes -- triggered by even small doses of the pesticide -- can be passed on to descendants across at least two generations. "We found the same DNA methylation patterns in the grandkid generation. That was surprising because they were not exposed to the insecticide," says Chen.In several other insect species, exposure to pesticides has been shown to change DNA methylation. And some epigenetic changes have been observed to be passed on to future generations of species that reproduce asexually -- such as the tiny crustacean The study was published in the December edition of the journal Over the last half-century, agricultural researchers and chemical companies have spent millions developing innovative chemical compounds to try to kill off this beetle that causes hundreds of millions of dollars of damage -- and almost all eventually fail. "Perhaps it's time to get off the pesticide treadmill of trying to introduce ever-more-toxic chemicals -- and recognize that evolution happens, regardless of what we throw at them," says Yolanda Chen. "We could be more strategic in understanding how evolutionary processes work -- and invest in more ecological approaches that would enable agriculture to be more sustainable."Epigenetics is an increasingly hot field. Basically, it's the study of how environmental stresses -- from starvation to air pollution to pesticides -- can add or remove chemical tags to an organism's DNA -- flipping a genetic switch that changes its health and behavior.DNA methylation was first shown to occur in human cancer in 1983 and since the early 2000s the epigenetics revolution in biology began to reveal how environmental change can turn certain genes on or off, leading to profound changes in an organism without changing its DNA. And it's well known that many insects in agricultural areas develop pesticide resistance; it's not just Colorado potato beetles. More than six hundred species have developed resistance to over three hundred pesticides, with tens of thousands of reports from around the world. A growing body of research shows that many of these involve epigenetic mechanisms.In their experiment, the UVM scientists, with a colleague from the University of Wisconsin, gathered adult beetles from organic farms in Vermont. They divided up the offspring, treating them with different doses of the pesticide imidacloprid -- some high, some low, some to a less-toxic chemical similar to imidacloprid -- and some to just water. After two generations, beetles whose grandparents had been treated to any level of pesticide showed decreased overall methylation -- while the ones exposed to water did not. Many of the sites where where the scientists found changes in methylation are with genes associated with pesticide resistance. The parallel response across all the pesticide treatments suggests that "mere exposure to insecticides can have lasting effects on the epigenetics of beetles," says Chen.It's one thing to suggest that stress changes a particular organism, quite another to suggest that physical characteristics it acquires by stress or behavior can get passed down for numerous generations. A blacksmith who grows strong from a lifetime of hard work should not expect her children to be extraordinarily strong too. So why does some stress lead to lasting change?The foundations of epigenetics remain mired in controversy, partly because it has been attached to largely discredited theories of "inheritance of acquired characters" -- an ancient idea that stretches back to Aristotle and is most strongly associated with Jean-Baptiste Lamarck, the nineteenth-century French naturalist who proposed that organisms pass down characteristics that are used or disused to their offspring.Although Lamarck's ideas were previously discredited by evolutionary biologists, the epigenetics revolution is making clear that evolution by natural selection doesn't have to just rely on random advantageous mutations showing up in the genetic code. In the case of the Colorado potato beetles studied at UVM, the research suggests that pesticides may flip a whole raft of epigenetic switches some of which can ramp up production of existing defenses against the toxins -- while changes in DNA methylation can unleash portions of the DNA called transposable elements. "These elements have also been called 'jumping genes' and are most closely related to viruses," says Chen, a professor in UVM's Department of Plant and Soil Science and fellow in the Gund Institute for Environment. "Due to their harmful effect on host genomes, they are usually suppressed by DNA methylation." But pesticide exposure, the new research suggests, may let them loose, allowing more mutations associated with pesticide resistance to generate.In short, the dynamic interplay between epigenetics and genetics points toward an explanation for the largely unexplained reality of rapid evolution and pesticide resistance. How these changes get passed on through multiple generations of sexual recombination remains mysterious -- but the new study strongly suggests that they do. "We have more to learn," says Chen, "about how people could manage evolution better."
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Environment
| 2,020 |
December 21, 2020
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https://www.sciencedaily.com/releases/2020/12/201218094504.htm
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Simple and cost-effective extraction of rare metals from industrial waste
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Many rare metals are in scarce supply, yet demand for use in electronics, medical instrumentation, and other purposes continues to increase. As waste, these metals pollute the environment and harm human health. Ideally, we would recycle the metals from waste for reuse. Unfortunately, current recycling methods are some combination of complex, expensive, toxic, wasteful, and ultimately inefficient.
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In an upcoming study in The researchers chemically modified ultrasmall particles of cellulose, an abundant and nontoxic biopolymer, to selectively adsorb silver and palladium ions at room temperature. Adsorption was nearly complete at acidic pH with acid concentrations of around 1 to 13 percent by volume. These are reasonable experimental conditions."The adsorbent selectively chelated the soft acid silver and palladium cations," explains lead author Foni Biswas. "Of the 11 competing base metals we tested, only copper and lead cations were also adsorbed, but we removed them with ease."Maximum metal ion adsorption was fast -- e.g., an hour for silver. Maximum adsorption commonly requires many hours with other approaches."Intraparticle diffusion did not hinder adsorption, which is an endothermic, spontaneous chemical process," explains senior author Hiroshi Hasegawa. "Maximum metal adsorption capacities -- e.g., 11 mmol/g for silver -- are substantially higher than that reported in prior research."After adsorption, the researchers simply incinerated the cellulose particles to obtain elemental silver or palladium powder. Subsequent higher-temperature incineration converted the powder into pellets. Cyanide or other toxic extractants were not required. Spectroscopic analyses indicated that the final metal pellets were in metallic rather than oxide form."We removed nearly all of the silver and palladium from real industrial waste samples," says lead author Biswas. "Obtaining pure and elemental metals proceeded as smoothly as in our trial runs."Palladium and silver are valuable metals yet natural supplies are increasingly limited. Future needs require that we recycle the metals that we already have in a practical manner. The research reported here is an important development that will avoid supply and distribution difficulties that will only increase in the coming years.
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Environment
| 2,020 |
December 21, 2020
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https://www.sciencedaily.com/releases/2020/12/201221101217.htm
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Goldilocks and the three quantum dots: Just right for peak solar panel performance
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Scientists in Australia have developed a process for calculating the perfect size and density of quantum dots needed to achieve record efficiency in solar panels.
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Quantum dots, human-made nanocrystals 100,000 times thinner than a sheet of paper, can be used as light sensitisers, absorbing infrared and visible light and transferring it to other molecules.This could enable new types of solar panels to capture more of the light spectrum and generate more electrical current, through a process of 'light fusion' known as photochemical upconversion.The researchers, from the ARC Centre of Excellence in Exciton Science, used lead sulfide quantum dots in their example. The algorithm is free to access and their results have been published in the journal Significantly, existing upconversion results achieved by test devices used organic sensitisers that do not work with silicon solar cells -- currently the most commonly available type of photovoltaics technology -- due to their inability to absorb much of the infrared part of the light spectrum.Using the right size and density of lead sulfide quantum dots as sensitisers would not only lead to efficiency increases but also be compatible with nearly all existing and planned solar cell technology.These findings indicate that when it comes to the quantum dot size, it isn't as simple as bigger meaning better.Using a basic theory, a larger quantum dot might appear to be able to capture more of the colours of sunlight, or more light of a certain wavelength, and be able to help create a device with higher efficiency.The researchers, though, have taken into account several practical constraints on quantum dot size.Most importantly, the near infrared part of sunlight at the Earth's surface has a complicated structure, influenced by water in the atmosphere and the sun's heat.This means the colour of the quantum dot must be tuned to match the peaks of sunlight, like adjusting a musical instrument to a certain pitch.According to corresponding author Dr Laszlo Frazer, the work demonstrates that a complete picture of the conditions influencing solar cell performance, from the star at the centre of our solar system to nanoscale particles, is necessary to achieve peak efficiency."This whole thing requires understanding of the sun, the atmosphere, the solar cell and the quantum dot," he said.While the projected efficiency increases demonstrated by these results remain modest, the potential benefits are considerable, as they can be used in nearly all solar devices, including those made from silicon.The next step for researchers is to design and create emitters that will transfer energy from the optimised quantum dot sensitisers most effectively."This work tells us a lot about the capturing of light," Laszlo said."Releasing it again is something that needs a lot of improvement. There's definitely a need for multidisciplinary contributions here."Author Benedicta Sherrie of Monash University said: "More work needs to be done on building the solar cell prototypes with these sensitizers (and hopefully with the suitable emitters), and to test them."I hope this research will eventually allow society to rely more on photovoltaic solar energy that is not only efficient, but also affordable."
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Environment
| 2,020 |
December 18, 2020
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https://www.sciencedaily.com/releases/2020/12/201218131917.htm
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Humpback whale songs provide insight to population changes
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Approximately 8,000-12,000 of the North Pacific humpback whale stock visits the shallow waters of the Hawaiian Islands seasonally to breed. During this time, mature males produce an elaborate acoustic display known as "song," which becomes the dominant source of ambient underwater sound between December and April. Following reports of unusually low whale numbers that began in 2015-16, researchers at the University of Hawaii at Manoa in collaboration with the Hawaiian Islands Humpback Whale National Marine Sanctuary, Oceanwide Science Institute and Woods Hole Oceanographic Institution, examined song chorusing recorded through long-term passive acoustic monitoring at six sites off Maui, as a proxy for whale populations between September 2014 and May 2019. The findings were published in Endangered Species Research.
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Using autonomous acoustic recorders called an "Ecological Acoustic Recorder," researchers calculated root-mean-square sound pressure levels (RMS SPL), a metric of the average amount of acoustic energy (how loud the soundscape is) per day.Over the course of the season, RMS SPL levels mirror the whales' migratory patterns. Levels increase starting in November through January when whales start arriving in the waters around the archipelago, peaking in February and March, before decreasing in April through May when whales start migrating back to their high-latitude feeding grounds. Researchers compared overall differences of this pattern and monthly averages of RMS SPL levels among years."Between the 2014-15 and 2017-18 seasons, we saw a continuous decrease in overall chorusing levels during the peak months of February and March of between -3 and -9 dB depending on location over the course of this four-year period," said Anke Kügler, a PhD candidate in marine biology, research assistant at the Hawaii Institute of Marine Biology and lead author of the paper. "Only in the 2018-19 season did levels increase again, reaching 2015-16 at most and even 2014-15 levels at some recording sites. Further, we saw a shift in the seasonal pattern, with peaks shifting to early- and mid-February from late February to early March. Overall, chorusing levels were not only significantly lower during the peak of the season, whales also appeared to depart the islands earlier than in the past."When anecdotal reports from the on-water community initially showed lower numbers of whales in 2015-16, this coincided with an El Niño event in the North Pacific. Researchers did not expect to see a decreasing trend for the subsequent two seasons, before chorusing levels seemed to bounce back in 2018-19.Further, a decrease of acoustic energy -6 dB means a decrease by 50%. While this does not automatically translate into half the number of whales, other researchers visually assessed numbers of mother-calf pairs off Maui and overall whales off Hawaii Island, and reported seeing declines of similar magnitude during the same time, indicating that researchers captured changes in population levels, not just changes in singing behavior."The Hawaii 'distinct population segments' has been delisted from the Endangered Species Act in 2016, assuming sustainable levels after decades of population increase," said Kügler. "However, in light of global change, continued monitoring is necessary to detect potential negative changes early and implement mitigation and adjust protection measures within Hawaiian waters, if necessary."Humpback whales are considered charismatic megafauna that hold a unique place in society, particularly modern Hawaiian culture. Further, whale watching is an important economic resource in Hawaii. As such, humpback whales are what is called a "flagship species." They have the potential to be the ambassador species for the entire region's ecosystem by helping to raise awareness of threats and global change impacts, on them and other species they share their habitat with, as well as their migration areas."The University of Hawaii has been a global leader in marine mammal research since the 1970s, therefore doing this kind of work and continuing on this tradition of high-impact marine mammal research enables the university to maintain that status as one of world's prime research universities," said Kügler."In addition, this collaborative project highlights and strengthens UH's existing long-term connection to NOAA," added Kügler. "I was able to do this research due to this close partnership and collaboration with NOAA and the Hawaiian Islands Humpback Whale National Marine Sanctuary."
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Environment
| 2,020 |
December 18, 2020
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https://www.sciencedaily.com/releases/2020/12/201218112456.htm
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Discovery of chromophores that emit light in the ultraviolet region when excited with visible light
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Fluorescence usually entails the conversion of light at shorter wavelengths to light at longer wavelengths. Scientists have now discovered a chromophore system that goes the other way around. When excited by visible light, the fluorescent dyes emit light in the ultraviolet region. According to the study published in the journal
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Fluorescent dyes absorb light at shorter wavelengths (high energy, e.g. blue light) and emit light at longer wavelengths (low energy, e.g. red light). Upconversion of light is much more difficult to achieve. Upconversion means that a fluorescent dye is excited with radiation in the visible range but emits in the ultraviolet. Such dyes could be used to run high-energy catalytic reactions such as solar-powered water splitting just using normal daylight as an energy source. Such dyes would expand the range of available excitation energy.Nobuhiro Yanai and colleagues at Kyushu University, Japan, are exploring multi-chromophore systems for their ability to upconvert fluorescence light. Yanai explains how upconversion works: "Fluorescence upconversion occurs when two chromophore molecules, which have been excited in the triplet state by a sensitizer, collide. This collision annihilates the sensitized energy and lifts the chromophores to a higher energy level. From there, they emit the energy as radiation."In practice, however, it is difficult to achieve effective upconverting chromophore designs -- existing systems need high-intensity radiation and still do not achieve more than ten percent efficiency. "The main reason for the low efficiency is that the sensitizer chromophore molecules also absorb much of the upconverted light, which is then lost," Yanai says.In contrast, the donor-acceptor chromophore pair developed by Yanai and colleagues exhibits energy levels that are so finely adjusted that it achieved a record-high 20 percent upconversion efficiency. Almost no back-absorption and low nonradiative loss occurred. The novel chromophore pair consisted of an iridium-based donor, which was an established sensitizer, and a naphthalene-derived acceptor, which was a novel compound.Low back-absorption and few radiative losses mean that the intensity of the exciting radiation can be low. The researchers reported that solar irradiance was sufficient to achieve high upconversion efficiency. Even indoor applications were possible using artificial light. The authors held an LED lamp above an ampoule filled with the chromophore solution and measured the intensity of the emitted UV light.
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Environment
| 2,020 |
December 18, 2020
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https://www.sciencedaily.com/releases/2020/12/201217112946.htm
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New discovery opens novel pathway for high-titer production of drop-in biofuels
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Using an unusual, light-dependent enzyme and a newly discovered enzymatic mechanism, researchers from Aarhus University and Massachusetts Institute of Technology have enabled the biological synthesis of high-yield industry relevant production of climate neutral drop-in fuels from biowaste.
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A special light-dependent enzyme, which was first discovered about three years ago, is the focal point in a new scientific discovery, that enables high-yield production of drop-in biofuels from biomass.In a study now published in The findings have allowed the researchers to successfully biosynthesize green fuels at close to industrially relevant levels of 1.47 gram per liter from glucose.The light-dependent enzyme, which originates from microalgae, has the particular characteristic that it can decarboxylate fatty acids into alkanes (thus converting cellulosic biomass into drop-in biofuels) using blue light as the only source of energy.The researchers artificially insert the enzyme into the cells of the oleaginous yeast Yarrowia Lipolytica thereby engineering its metabolism. The yeast synthesizes glucose, originating from biomass, into lipids (specifically the molecules free fatty acids and fatty acyl-CoAs) which is then converted to alkanes by the enzyme in a metabolic reaction called fatty acid photodecarboxylase, in short FAP.But ever since the discovery of the enzyme, it has been assumed, that free fatty acids are the enzyme's preferred reactant in the FAP process. That an abundance of free fatty acids would result in higher yield biofuel production.Wrong, however."In our study, we have proved that fatty acyl-CoA -- and not free fatty acid -- is the preferred reactant for the light-dependent enzyme. This finding has been successfully used in our study to metabolize 89 per cent of fatty acyl-CoA into alkanes, reaching titers of 1.47 g/l from glucose," says Bekir Engin Eser, an assistant professor at Aarhus University.The predominant production of oleochemical based drop-in fuels today are made by converting 'conventional' oleochemicals such as vegetable oils, used cooking oils, tallow, and other lipids to hydrocarbons (mainly alkanes) using energy intense chemical treatment methods.However, sourcing large quantities of more or less sustainable lipid feedstocks at a low enough cost to result in profitable drop-in biofuel production remains a challenge that severely limits the expansion of this production platform. And furthermore, this production is competing with food supply.Biosynthesis constitutes a cheap and sustainable solution, where the production is instead based on the conversion of cellulosic biomass -- the most abundant renewable natural biological resource available on Earth.Biological synthesis of alkanes from fatty acids is not a native, preferable metabolic pathway for the yeast however, since alkanes are toxic to its cells. Therefore, researchers use special ability enzymes for this purpose and encode the corresponding genes into the cells of the yeast.The new discovery is a possible breakthrough in biosynthesis of drop-in fuels, since the researchers -- for the first time ever using this process -- have utilized the new knowledge to synthesize green fuels at a level that's relevant for future industrial production:"Previous metabolic engineering studies would target maximizing the concentration of free fatty acids in the cells that are being engineered. But now, with this discovery, we know that it is fatty acyl-CoA that needs to be maximized. This is important news for synthetic biology applications, and we can now begin to maximize the flux of the fatty acyl-coA into this engineered metabolic pathway to reach even higher titers in the future," says Associate Professor Zheng Guo from Aarhus University.
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Environment
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December 17, 2020
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https://www.sciencedaily.com/releases/2020/12/201217135344.htm
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Study tracks elephant tusks from 16th century shipwreck
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In 1533, the Bom Jesus -- a Portuguese trading vessel carrying 40 tons of cargo including gold, silver, copper and more than 100 elephant tusks -- sank off the coast of Africa near present-day Namibia. The wreck was found in 2008, and scientists say they now have determined the source of much of the ivory recovered from the ship.
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Their study, reported in the journal The ivory had been stowed in a lower level of the Bom Jesus under a weighty cargo of copper and lead ingots, said Alida de Flamingh, a postdoctoral researcher at the University of Illinois Urbana-Champaign who led the study with U. of I. animal sciences professor Alfred Roca and anthropology professor Ripan Malhi."When the ship sank, the ingots compressed the tusks into the seabed, preventing a lot of physical erosion by sea currents that can lead to the destruction and scattering of shipwreck artifacts," de Flamingh said. "There is also an extremely cold sea current in that region of coastal Namibia, which likely also helped preserve the DNA in the shipwrecked tusks."The team extracted DNA from 44 tusks.By analyzing genetic sequences known to differ between African forest and savanna elephants, the scientists determined that all of the tusks they analyzed belonged to forest elephants. A further examination of mitochondrial DNA, which is passed only from mothers to their offspring, offered a more precise geographic origin of the elephant tusks than is otherwise available."Elephants live in matriarchal family groups, and they tend to stay in the same geographic area throughout their lives," de Flamingh said. "By comparing the shipwrecked ivory mitochondrial DNA with that from elephants with known origins across Africa, we were able to pinpoint specific regions and species of elephants whose tusks were found in the shipwreck."All 44 tusks were from elephants residing in West Africa. None originated in Central Africa."This is consistent with the establishment of Portuguese trading centers along the West African coast during this period of history," de Flamingh said.The team used DNA to trace the elephants to 17 family lineages, only four of which are known to persist in Africa."The other lineages disappeared because West Africa has lost more than 95% of its elephants in subsequent centuries due to hunting and habitat destruction," Roca said.The team is adding the new DNA sequences to the Loxodonta Localizer, an open-access tool developed at the U. of I. that allows users to compare mitochondrial DNA sequences collected from poached elephant tusks with those in an online database collected from elephants across the African continent.To learn more about the environments the elephants inhabited, Oxford University Pitt Rivers Museum research fellow and study co-author Ashley Coutu analyzed the stable carbon and nitrogen isotopes of 97 tusks. The ratios of these isotopes differ depending on the types of plants the elephants consumed and the amount of rainfall in the environment.That analysis revealed that the elephants lived in mixed habitats, switching from forested areas to savannas in different seasons, most likely in response to water availability."Our data help us to understand the ecology of the West African forest elephant in its historic landscape, which has relevance to modern wildlife conservation," Coutu said."Our study analyzed the largest archaeological cargo of African ivory ever found," de Flamingh said. "By combining complementary analytical approaches from multiple scientific fields, we were able to pinpoint the origin of the ivory with a resolution that is not possible using any single approach. The research provides a framework for examining the vast collections of historic and archaeological ivories in museums across the world."de Flamingh conducted the DNA analysis in the Malhi Molecular Anthropology Laboratory at the Carl R. Woese Institute for Genomic Biology at the U. of I. This project was a multi-institutional effort involving collaborators in Namibia, South Africa, the United Kingdom and the U.S.The U.S. Fish and Wildlife Service African Elephant Conservation Fund, U.S. Department of Agriculture, National Research Foundation of South Africa, Department of Science and Technology of South Africa, and Claude Leon Foundation supported this research.
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Environment
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December 17, 2020
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https://www.sciencedaily.com/releases/2020/12/201217135340.htm
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Territorial red squirrels live longer when they're friendly with their neighbors
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Though red squirrels are a solitary and territorial species, a 22-year study of these squirrels in the Yukon suggests that they have a higher chance of survival and a greater number of offspring when living near the same neighbors year after year. Surprisingly, the findings -- appearing December 17 in the journal
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"Red squirrels live on their individual territory, and they rarely come into physical contact with one another, but given the value of familiar neighbors, our study raises this really interesting possibility that they might cooperate with their competitors," says first author Erin Siracusa, a postdoctoral researcher at the University of Exeter, who conducted this research as a doctoral candidate at the University of Guelph. "What this cooperation looks like, whether it's sharing of food resources, or actively alarm-calling to warn their neighbors of predators, or potentially even forming coalitions to protect the neighboring territories from usurpers, we don't know. But I would argue based on our findings that despite their solitary nature, red squirrels do engage in social interactions and can have important social relationships."While it's known that social relationships play a key role for animals that live in groups, Siracusa was interested in learning how social relationships affect solitary, territorial species -- who rarely physically interact with their own kind. Through the Kluane Red Squirrel Project, Siracusa and her colleagues from the University of Guelph (Andrew G. McAdam), the University of Alberta (Stan Boutin), the University of Saskatchewan (Jeffrey E. Lane), and the University of Michigan (Ben Dantzer) followed 1,009 individuals over 22 years. Each summer, every squirrel was given colored ear tags so researchers could record who lived where and who shared territory boundaries.Siracusa had previously observed that red squirrels with stable social relationships -- established in part through defensive calls known as "rattles" that the squirrels make to identify themselves -- were less likely to intrude on each other's territories and pilfer each other's cache. "Once they live next to each other long enough to agree on these territory boundaries, they sort of enter into this gentleman's agreement, saying, 'Okay, we've established these territory boundaries. We know where they are. We're not going to waste our time and energy fighting over these boundaries anymore,'" she says. This reduced aggression in familiar neighbors, known as the "dear enemy" phenomenon, has been established in many species previously, but researchers haven't been able to easily tie the phenomenon to a fitness advantage.In this project, Siracusa and her team set out to discover whether there were any survival and reproduction benefits for squirrels who lived near their blood relatives or lived near non-related squirrels over a number of years. What they found was that living near relatives didn't provide any biological benefits -- which was surprising, since animals that share the same genes are generally more likely to act altruistically toward one another. But they did find that regardless of relatedness, the longer squirrels lived with each other, the more likely they were to survive into the next year and produce more offspring.The benefits of this familiarity among older squirrels were even more pronounced. "The benefits of familiarity were strong enough to completely offset the negative effects of aging," Siracusa says. "For example, for a four-year-old red squirrel that ages by one year, their survival probability decreases from 68% to 59%. But if that same squirrel that ages one year also maintains all of their neighbors, that probability of survival actually increases from 68% to 74%." However, she notes that only a small percentage of squirrels maintain their neighbors from one year to the next, so not all squirrels experience the benefits of familiarity in old age.To make sure their results reflected the effects of familiarity among neighbors rather than localized areas with a particularly good habitat or low risk of predators, Siracusa and her team tested for spatial correlation in survival and reproductive success and found that it was rare and inconsistent.More broadly, she suggests that these findings might help us better understand the evolution of territorial systems. They might help explain territorial behaviors such as migratory species returning to the same place year after year, sedentary species maintaining relatively stable territories or home ranges throughout their lifetime, and animal mothers only rarely giving up their territory for the sake of their offspring -- all of which could relate to animals not wanting to renegotiate social relationships. "In order for territorial systems to arise, the benefit of being territorial has to outweigh the costs of defending those resources, so it's not surprising that we should see the evolution of a mechanism that works to minimize those costs of territoriality," says Siracusa."At the risk of waxing poetic about squirrels," she says, "I think there is a sort of interesting lesson here that red squirrels can teach us about the value of social relationships. Red squirrels don't like their neighbors. They're in constant competition with them for food and mates and resources. And yet, they have to get along to survive. In the world right now, we're seeing a lot of strife and division, but perhaps this is a lesson worth bearing in mind: red squirrels need their neighbors, and maybe we do too."
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Environment
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December 17, 2020
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https://www.sciencedaily.com/releases/2020/12/201217135254.htm
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Crops near Chernobyl still contaminated
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Crops grown near Chernobyl are still contaminated due to the 1986 nuclear accident, new research shows.
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Scientists analysed grains including wheat, rye, oats and barley and found concentrations of radioactive isotopes -- strontium 90 and/or caesium 137 -- above Ukraine's official safe limits in almost half of samples.The researchers also examined wood samples and found three quarters contained strontium 90 concentrations above Ukrainian limits for firewood.The study was carried out by the Greenpeace Research Laboratories at the University of Exeter and the Ukrainian Institute of Agricultural Radiology."We focussed on strontium 90 because it is known to be currently present in soil mostly in bioavailable form, meaning it can be taken up by plants," said lead author Dr Iryna Labunska, of the Greenpeace Research Laboratories at the University of Exeter."Ukrainian government monitoring of goods containing strontium 90 ended in 2013, but our study clearly shows this needs to continue."People need to be aware of the ongoing contamination of soil and plants, and they need to be advised on the safest agricultural and remediation methods."We found very high levels of strontium 90 in wood ash -- yet many people still use ash from their fires as a crop fertiliser."Dr David Santillo, also of the Greenpeace Research Laboratories, added: "Our findings point to ongoing contamination and human exposure, compounded by lack of official routine monitoring."This research also highlights the potential for Chernobyl-derived radiation to be spread more widely again as more and more wood is used for power generation in the region."The study analysed 116 grain samples collected during 2011-19 from fields in 13 settlements in the Ivankiv district of Ukraine -- about 50km south of the power plant and outside its "exclusion zone."Wood samples -- mostly pine -- were collected from 12 locations in the same district during 2015-19.The study found:- Taking both strontium 90 and caesium 137 into account, combined activity concentrations of these isotopes were above permissible levels in 48% of grain samples.- Nevertheless, modelled data show that the greater part of the Ivankiv district could produce grains containing strontium 90 below corresponding Ukrainian permissible levels.- In the case of wood, it is estimated that levels of strontium 90 could exceed permissible levels for firewood in forest woods from vast areas in the north-east of the Ivankiv district.- Wood from these territories may still contain strontium 90 above permissible levels by the end of this century.- In one sample of ash from a domestic wood-burning oven, strontium 90 was found at a level 25 times higher than in the most contaminated wood sample collected in this study.The authors recommend:- Government-led agricultural policies such as liming and using organic fertilisers, which could reduce strontium 90 concentrations by about half.- Decreasing or eliminating the use of radioactively contaminated wood in fires.- Establishing a programme to monitor radioactive contamination of ash in both households and at the local thermal power plant (TPP).- Providing the population with information on safe handling of radioactively contaminated ash, and establishing a centralised disposal service for such ash.Professor Valery Kashparov, Director of the Ukrainian Institute of Agricultural Radiology, added: "Contamination of grain and wood grown in the Ivankiv district remains of major concern and deserves further urgent investigation."Similarly, further research is urgently needed to assess the effects of the Ivankiv TPP on the environment and local residents, which still remain mostly unknown."In a previous study, the researchers found that milk in parts of Ukraine had radioactivity levels up to five times over the country's official safe limit.The new study was supported by the National University of Life and Environmental Sciences of Ukraine, the Ministry of Education and Science of Ukraine, and the Science Unit of Greenpeace International.
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Environment
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December 17, 2020
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https://www.sciencedaily.com/releases/2020/12/201217135242.htm
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Transforming clean energy technology
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By some estimates, the amount of solar energy reaching the surface of the earth in one year is greater than the sum of all the energy we could ever produce using non-renewable resources. The technology necessary to convert sunlight into electricity has developed rapidly, but inefficiencies in the storage and distribution of that power have remained a significant problem, making solar energy impractical on a large scale. However, a breakthrough by researchers at UVA's College and Graduate School of Arts & Sciences, the California Institute of Technology and the U.S. Department of Energy's Argonne National Laboratory, Lawrence Berkeley National Laboratory and Brookhaven National Laboratory could eliminate a critical obstacle from the process, a discovery that represents a giant stride toward a clean-energy future.
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One way to harness solar energy is by using solar electricity to split water molecules into oxygen and hydrogen. The hydrogen produced by the process is stored as fuel, in a form that can be transferred from one place to another and used to generate power upon demand. To split water molecules into their component parts, a catalyst is necessary, but the catalytic materials currently used in the process, also known as the oxygen evolution reaction, are not efficient enough to make the process practical.Using an innovative chemical strategy developed at UVA, however, a team of researchers led by chemistry professors Sen Zhang and T. Brent Gunnoe have produced a new form of catalyst using the elements cobalt and titanium. The advantage of these elements is that they are much more abundant in nature than other commonly used catalytic materials containing precious metals such as iridium or ruthenium."The new process involves creating active catalytic sites at the atomic level on the surface of titanium oxide nanocrystals, a technique that produces a durable catalytic material and one that is better at triggering the oxygen evolution reaction." Zhang said. "New approaches to efficient oxygen evolution reaction catalysts and enhanced fundamental understanding of them are key to enabling a possible transition to scaled-use of renewable solar energy. This work is a perfect example of how to optimize the catalyst efficiency for clean energy technology by tuning nanomaterials at the atomic scale."According to Gunnoe, "This innovation, centered on achievements from the Zhang lab, represents a new method to improve and understand catalytic materials with a resulting effort that involves the integration of advanced materials synthesis, atomic level characterization and quantum mechanics theory.""Several years ago, UVA joined the MAXNET Energy consortium, comprised of eight Max Planck Institutes (Germany), UVA and Cardiff University (UK), which brought together international collaborative efforts focused on electrocatalytic water oxidation. MAXNET Energy was the seed for the current joint efforts between my group and the Zhang lab, which has been and continues to be a fruitful and productive collaboration," Gunnoe said.With the help of the Argonne National Laboratory and the Lawrence Berkeley National Laboratory and their state-of-the-art synchrotron X-ray absorption spectroscopy user facilities, which uses radiation to examine the structure of matter at the atomic level, the research team found that the catalyst has a well-defined surface structure that allows them to clearly see how the catalyst evolves in the meantime of the oxygen evolution reaction and allows them to accurately evaluate its performance."The work used X-ray beamlines from the Advanced Photon Source and the Advanced Light Source, including a portion of a 'rapid-access' program set aside for a quick feedback loop to explore emergent or pressing scientific ideas," said Argonne X-ray physicist Hua Zhou, a co-author on the paper. "We're very excited that both national scientific user facilities can substantially contribute to such clever and neat work on water splitting that will provide a leap forward for clean energy technologies."Both the Advanced Photon Source and the Advanced Light Source are U.S. Department of Energy (DOE) Office of Science User Facilities located at DOE's Argonne National Laboratory and Lawrence Berkeley National Laboratory, respectively.Additionally, researchers at Caltech, using newly developed quantum mechanics methods were able to accurately predict the rate of oxygen production caused by the catalyst, which provided the team with a detailed understanding of the reaction's chemical mechanism."We have been developing new quantum mechanics techniques to understand the oxygen evolution reaction mechanism for more than five years, but in all previous studies, we could not be sure of the exact catalyst structure. Zhang's catalyst has a well-defined atomic structure, and we find that our theoretical outputs are, essentially, in exact agreement with experimental observables," said William A. Goddard III, a professor of chemistry, materials science, and applied physics at Caltech and one of the project's principal investigators. "This provides the first strong experimental validation of our new theoretical methods, which we can now use to predict even better catalysts that can be synthesized and tested. This is a major milestone toward global clean energy.""This work is a great example of the team effort by UVA and other researchers to work towards clean energy and the exciting discoveries that come from these interdisciplinary collaborations," said Jill Venton, chair of UVA's Department of Chemistry.
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Environment
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December 17, 2020
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https://www.sciencedaily.com/releases/2020/12/201217135231.htm
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Upcycling: New catalytic process turns plastic bags into adhesives
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While many cities and eight states have banned single-use plastics, bags and other polyethylene packaging still clog landfills and pollute rivers and oceans.
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One major problem with recycling polyethylene, which makes up one-third of all plastic production worldwide, is economic: Recycled bags end up in low-value products, such as decks and construction material, providing little incentive to reuse the waste.A new chemical process developed at the University of California, Berkeley, converts polyethylene plastic into a strong and more valuable adhesive and could change that calculus."The vision is that you would take a plastic bag that is of no value, and instead of throwing it away, where it ends up in a landfill, you would turn it into something of high value," said John Hartwig, the Henry Rapoport Chair in Organic Chemistry at UC Berkeley and leader of the research team. "You couldn't take all of this recycled plastic -- hundreds of billions of pounds of polyethylene are produced each year -- and turn it into a material with adhesive properties, but if you take some fraction of that and turn it into something that is of high value, that can change the economics of turning the rest of it into something that is of lower value."For most plastics, recycling means chopping it up and forming it into generic products, in the process tossing out many of the properties painstakingly engineered into the original plastic, such as pliability and ease of processing. And while new methods of recycling can break down plastics into their chemical constituents for use as fuels or lubricants, these products, too, are low-value and can be environmentally questionable -- another fossil fuel to burn -- or have a short lifetime.To make recycling more attractive, researchers and the plastics industry have been looking for ways to "upcycle" -- that is, convert recycled plastic into something more valuable and longer-lived.The chemical process that Hartwig and his colleagues developed keeps many of the original properties of polyethylene, but adds a chemical group to the polymer that makes it stick to metal: something polyethylene normally does poorly. His team showed that the modified polyethylene can even be painted with water-based latex. Latex easily peels off standard low-density polyethylene, referred to as LDPE.The paper describing this process will be published online Dec. 17 in the journal "We are able to enhance adhesion, while preserving all the other traits of polyethylene that the industry finds so useful," said co-author Phillip Messersmith, the Class of 1941 Professor in UC Berkeley's departments of bioengineering and materials science and engineering. "The processability, thermal stability and mechanical properties seem to be unharmed while enhancing adhesion. That is tricky to do. That is really where we have some exciting things to show."While the process is not yet economical for industrial use, Hartwig believes that it can be improved and could be the starting point for adding other properties besides stickiness. The success also hints that other catalysts could work with other types of plastics, such as the polypropylene found in recycled plastic bottles, to produce higher-value products that are economically attractive.Hartwig specializes in designing new catalytic processes -- in this case, adding small chemical units to large hydrocarbon chains, or polymers, in very specific places -- to create "functionalized polymers" with new and useful properties. Such reactions are difficult, because a major selling point of plastics is that they are resistant to chemical reactions.For this project, he wanted to see if he could add a hydroxyl group -- oxygen bound to hydrogen, or OH -- at a small fraction of the carbon-hydrogen bonds along the polyethylene chain."Polyethylene usually has between 2,000 and 10,000 carbons in a chain, with two hydrogens on each carbon -- really, it is an ocean of CH2 groups, called methylenes," he said. "We dipped into the literature to look for the most active catalyst we could find for functionalization of a methylene position."The catalyst would have to work at high temperatures, since the solid recycled plastic has to be melted. Also, it would have to work in a solvent that is nonpolar, and thus able to mix with polyethylene, which is nonpolar. This is one reason it does not stick to metals, which are polar, or charged.Hartwig and postdoctoral associate Liye Chen settled on a ruthenium-based catalyst (polyfluorinated ruthenium porphyrin) that satisfied these requirements and also could add OH groups to the polymer chain without the highly reactive hydroxyl breaking the polymer chain apart.The reaction, surprisingly, produced a polyethylene compound that sticks tightly to aluminum metal, presumably by means of the OH molecules affixed along polyethylene's hydrocarbon chain. To better understand the adhesion, Chen teamed up with Katerina Malollari, a graduate student in Messersmith's lab, which focuses on biological tissues with adhesive properties -- in particular, a glue produced by mussels.Chen and Malollari discovered that adding a relatively small percentage of alcohol to the polymer boosted adhesion 20 times."The catalysis introduced chemical changes to less than 10% of the polymer, yet enhanced dramatically its ability to adhere to other surfaces," Messersmith said.Getting polyethylene to adhere to things -- including latex paint -- opens up many opportunities, he added. Artificial hip sockets and knee implants often integrate polyethylene with metal components and could be made to adhere better to metal. Functionalized polyethylene could be used to coat electrical wire, provide the glue that sticks other polymers together -- in milk cartons, for example -- or make more durable composites of plastic and metal, such as in toys."The utility here is being able to introduce these functional groups, which help solve many longstanding problems in polyethylene adhesion: adhesion of polyethylene to other polyethylene or to other polymers, as well as to metal," Messersmith said.Hartwig foresees more opportunities for functionalization of complex polymers, including the most common plastic, polypropylene."We are one of the only groups anywhere that has been able to selectively introduce a functional group to long-chain hydrocarbon polymers," he said. "Other people can break the chains, and others can cyclize the chains, but to actually introduce a polar functional group into the chains is something that nobody else has been able to do."Hartwig's team also included UC Berkeley graduate student Adam Uliana. The work was supported by the U.S. Department of Energy (DE-AC02- 05CH11231) and the National Institutes of Health (R37 DE014193).
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Environment
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December 17, 2020
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https://www.sciencedaily.com/releases/2020/12/201217112939.htm
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How scientists are using declassified military photographs to analyse historical ecological change
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Researchers are using Cold War spy satellite images to explore changes in the environment, including deforestation in Romania, marmot decline in Kazakhstan and ecological damage from bombs in Vietnam.
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Ecologists have harnessed new advances in image processing to improve analysis of declassified US military intelligence photographs and detect previously unseen changes in the environment. Dr.Catalina Munteanu, of Humboldt University, and Dr.Mihai Daniel Nita, Transilvania University of Brașov, present new findings from the US Geological Survey declassified satellite imagery. The main data source for the analyses are Cold War Spy satellite images, which were collected by the US since 1960, initially to monitor the Sino-Soviet bloc. Eight satellites took pictures on film roll, which were then parachuted back into the atmosphere, where a perfectly timed US military plane snatched it mid-air before it could be intercepted. The researchers obtained the photos through the U.S. Geological Survey's Earth Resources Observation and Science (EROS) Centre, after being declassified in 1995 under an executive order by President Bill Clinton. This type of film data has been given an upgrade, by employing drone image processing software, using a rectification technique known as structure from motion. Mihai, a co-author, a pioneer of this method commented "The mathematic procedure behind the drone image processing software is structure from motion. This approach allows us to process historical aerial or satellite images faster and more precise than the traditional approach." This essentially creates a historical Google-Earth style of map, for satellite imagery taken as far back as the Cold War. Previously, the same research group had utilised the CORONA dataset to analyse photos of agricultural landscapes in Kazakhstan between 1960's and 1970's. These photos were used to identify population declines in steppe marmots due to a reduction in burrow number. On marmots, Catalina Munteanu says, "Marmot population declined over the past 50 years in Kazakhstan- and this is a decline that we might have missed, if only looking at short time periods of 10-15 years for which modern data is available.The authors present several new findings, in addition to the published research on marmots in Kazakhstan. One use included revealing the extent of large-scale deforestation in the aftermath of the Second World War in Romania.Pictures from the 1960's revealed the watershed was completely clear cut by Soviet-Romanian companies as a reparation to the war. In 2015, a Google Earth image of the same area, showed the secondary forest regrowth after 60 years.Interestingly, new examination of photos from the Vietnam War has revealed the extensive ecological damage caused by explosions. Mihai Daniel Nita, in a separate piece of work, has assessed the expansion of agricultural land in previously ravaged forests, as well as craters from the impact of bomb explosions, which have been transformed into fish farming ponds. Spy satellite imagery can be used to map warfare-induced deforestation and changing agricultural practices in Vietnam. This work demonstrates that often our choice of baselines is dictated by data availability, and that by using different data sources, we may shift the baselines against which we quantify change. The interpretation of environmental change will depend heavily on the reference points we choose. Catalina and the co-authors caution that "this is a reminder to be very careful in our interpretations of environmental change. All data sources have their limitations and maybe also integrate these data. A good idea is to consider integrating across multiple data sources whenever possible." There may be many more applications of the data, such as mapping the development of cities and built infrastructure. Catalina commented, "photos of this nature can also be a direct source of information (e.g., a penguin colony detected on an ice shelf) or be an indication of species or their habitat (e.g., previous work on the burrows of marmots in Kazakhstan)." It is expected that large scale applications of historical satellite imagery data, as seen here, can set an example for the expansion of the use of these data into other disciplines relating to human environment interactions. Future work could involve investigated ecological shock events such as war, and how this modified landscape has influenced the land use change itself. Catalina Munteanu's talk will be available on-demand from the 14th -18th of December 2020 at the Festival of Ecology. Parts of this work are unpublished and has not been through the peer-review process as of yet. This online conference will bring together 1,400 ecologists from than 50 countries to discuss the most recent breakthroughs in ecology.
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Environment
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December 17, 2020
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https://www.sciencedaily.com/releases/2020/12/201217095511.htm
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Electron-producing microbes power sustainable wastewater treatment
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WSU researchers have developed a sustainable wastewater treatment system that relies on electron-producing microbial communities to clean the water.
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The work could someday lead to reduced reliance on the energy-intensive processes that are used to move and treat wastewater, which accounts for as much as two percent of the total electrical energy consumption in the United States.Led by Abdelrhman Mohamed, postdoctoral research associate, and Haluk Beyenal, Paul Hohenschuh Distinguished Professor in the Gene and Linda Voiland School of Chemical Engineering and Bioengineering, the researchers report on their work in the journal, In wastewater treatment, aeration is an energy intensive and necessary procedure to remove contaminants. Pumps work continuously to mix air into water, adding oxygen that bacteria then use to oxidize organic matter and contaminants. In their work, the researchers used a unique microbial fuel cell system they developed as a substitute for external aeration."If we cut the energy use even by a small percentage in the U.S., that is billions of dollars in annual costs," said Mohamed. "Energy costs are one part but that also means reducing environmental emissions, too."Microbial fuel cells work by having microbes convert chemical energy to electricity in a manner that is similar to a battery. They don't generate a lot of electricity, so they have been used in low-power applications especially in remote areas where batteries are not feasible.In the case of wastewater treatment, the microbial fuel cell can fill the role that aeration and oxygen plays -- accepting electrons that bacteria generate as a product of their metabolic work.In addition to substituting for the oxygen, the system can also generate a small amount of electricity, which can be used to do additional aeration."We tried to think about it in two steps," said Mohamed. "We lower the energy costs because you don't have to aerate and add oxygen, but the second part is we generate a little power that we can use for some useful applications in the wastewater treatment plant itself.""It's like we're double dipping," added Beyenal. "We use the electrodes and then the electron acceptor to promote microbial growth. On the other hand, we gain a little bit of electricity for the pump and to aerate. With this approach it is more powerful and can treat the wastewater faster."The fuel cells have been used experimentally in wastewater treatment systems under ideal conditions, but under real-world and varying conditions, they often fail."The microbial fuel cells lack internal regulation controlling the potential of anodes and cathodes, and thus cell potential," said Mohamed. "This can cause system failure."In the system the WSU team developed, the researchers added an extra electrode that allows additional control to their fuel cell system. The system is switchable. It can either work by itself as a microbial fuel cell, using no energy as it slowly cleans up waste, or it can be switched to one that uses a smaller amount of energy than aeration and that cleans more intensively. Mohamed invented a cheap portable electronic device that controls the electrodes.The researchers were able to operate their system for a year in the laboratory without failure as well as at the pilot scale at a test wastewater treatment facility in Moscow, Idaho. The pilot scale treatment facility is owned and operated by University of Idaho Environmental Engineering Professor Erik R. Coats, who was a collaborator on the project. The system removed waste at comparable rates to aeration.The system could potentially be used entirely independently from the power grid, and the researchers hope it could someday be used for small scale wastewater treatment facilities, such as for clean up around cattle operations or in very rural areas."Over time, we have made a lot of progress," said Mohamed, who first became interested in microbial fuel cells as an undergraduate at WSU. "There are still challenges that we need to overcome to see this as a real application, but it's exciting to see the field moving significantly over a period of time.""These are difficult systems to build," added Beyenal. "I think everything is so easy when I write the proposal, but this takes a lot of time and a lot of new discovery. There is nothing like this on the market."The work was funded by the Office of Naval Research.
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Environment
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December 17, 2020
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https://www.sciencedaily.com/releases/2020/12/201217090417.htm
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New path to rare earth mineral formation has implications for green energy and smart tech
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Researchers from Trinity College Dublin have shed new light on the formation mechanisms of a rare earth-bearing mineral that is in increasingly high demand across the globe for its use in the green energy and tech industries.
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Their discovery has important economic implications because there are no substitute alternatives to these rare earth elements (REEs), which are indispensable due to their ability to form small and very powerful magnets essential for smart devices and low-carbon energy generation (e.g., electronics, wind turbines, hybrid cars).Most REEs are exploited in carbonatite deposits (the largest known carbonatite is the Bayan Obo in China), but scientists still debate how and why they form due to their complicated mineralogy, element composition and geologic history.There are more than 250 known REE-bearing minerals, but only three are economically viable and exploited commercially. Bastnäsite is likely the primary valuable mineral for REES in the world and was the focus of the Trinity team's study.By considering how water containing REEs interacted with calcite, a mineral that is ubiquitous in nature and often present in hydrothermal environments, the team discovered a new pathway by which bastnäsite formed.Adrienn Maria Szucs, PhD Candidate, Trinity, is the first author of the study, which has just been published by the international journal "The crystallisation pathway we discovered reveals that in some rare earth-bearing deposits the origin of bastnäsite could be simply a consequence of the interaction of calcite with rare earth-rich fluids. This is not the only reaction that forms bastnäsite but the discovery is particularly important because calcite is found everywhere and is also the most stable calcium carbonate in nature. As a result, it suggests it should be possible to support the formation of bastnäsite under the right conditions."Juan Diego Rodriguez-Blanco, Ussher Assistant Professor in Nanomineralogy at Trinity, and funded investigator in the Irish Centre for Research in Applied Geosciences (iCRAG), is the Principal Investigator. He said:"The use of REEs for high-tech products is continually increasing over the years, and therefore the demand for them is also shooting up. This has generated significant geopolitical competition because many REEs have become very valuable."Unfortunately, extracting and refining REEs is both financially and environmentally expensive, so work like this is important for bettering our understanding of formation mechanisms of bastnäsite, which in turn helps us improve existing extraction and refinement methods."
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Environment
| 2,020 |
December 16, 2020
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https://www.sciencedaily.com/releases/2020/12/201216155215.htm
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Green chemistry creates coatings from nature
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Organic chemists from the University of Groningen and the Dutch multinational company AkzoNobel, a major global producer of paints and coatings, developed a process that allows them to turn biomass into a high-quality coating using light, oxygen and UV light. This process combines a renewable source with green chemistry and could replace petrochemical-based monomers such as acrylates, which are currently used as building blocks for coatings, resins and paints. A paper on the new process was published in the journal
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Coatings are everywhere, from the paint on your house to a protective layer on the screen of your smartphone. They protect surfaces from scratches, influences of the weather or everyday wear. Most coatings are made up of polymers based on acrylate monomers, with the global production of acrylate exceeding 3.5 million tonnes a year, all produced from fossil oil.To make these coatings more sustainable, scientists from the University of Groningen, led by Professor of Organic Chemistry Ben Feringa, teamed up with scientists from coating producer AkzoNobel. 'We wanted to use lignocellulose as the starting material,' says George Hermens, a PhD student in the Feringa group and first author of the paper in Science Advances. Lignocellulose makes up 20 to 30 per cent of the woody parts of plants and is the most abundantly available raw biomass material on Earth. Currently, it is mainly used as a solid fuel or used to produce biofuels.'Lignocellulose can be cracked with acid to produce the chemical building block furfural, but this needs to be modified to make it suitable for the production of coatings,' explains Hermens. He used a process that has been developed in their group to convert the furfural into a compound, hydroxybutenolide, that resembles acrylic acid. 'The chemical conversion uses only light, oxygen and a simple catalyst and produces no waste. The only side product is methyl formate, which is useful as a replacement for chlorofluorocarbons in other processes.'Part of the structure of hydroxybutenolide is similar to acrylate, but the reactive part of the molecule is a ring structure. 'This means that it is less reactive than acrylate and our challenge was to further modify the molecule so that it would produce a useful polymer.' This was achieved by adding different green or biobased alcohols to the hydroxybutenolide, creating four different alkoxybutenolide monomers.These monomers can be transformed into polymers and coatings with the help of an initiator and UV light. 'Coatings are made up of cross-linked polymer chains. By combining different monomers, we could get cross-linked polymers with different properties.' For example, while all polymers would coat glass, one combination was able to also form a coating on plastic. And by adding more rigid monomers, a harder coating was formed, with properties comparable to those of coatings on cars. In this way, these coatings are adaptable for different purposes.'We managed to create coatings from a renewable source, lignocellulose, using green chemistry,' concludes Hermens. 'And the quality of our coatings is similar to that of current acrylate-based coatings.' For two steps in the process, patent applications have been filed with AkzoNobel, the industrial partner in the project. Hermens is now working on a different building block derived from furfural to produce other types of polymer coatings.The project was initiated by the Advanced Research Center Chemical Building Blocks Consortium (ARC CBBC), a Dutch national public-private research centre that develops new chemical processes and chemical building blocks for novel energy carriers, materials and chemicals for sustainable chemistry. Hermens' supervisor, Ben Feringa, is one of the founders of this centre. The ARC CBBC is a national initiative with partners from industry, academia and government. There are three universities involved (Utrecht University, the University of Groningen and Eindhoven University of Technology) and major industrial partners (AkzoNobel, Shell, Nouryon and BASF), as well as the ministries of Education, Culture and Science and of Economic Affairs and Climate Policy and the Dutch Research Council (NWO). Feringa: 'The programme entails all the steps from fundamental scientific discovery to process and product development. In this long-term partnership, universities and the chemical industry join forces to develop the green chemistry of the future.'
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Environment
| 2,020 |
December 16, 2020
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https://www.sciencedaily.com/releases/2020/12/201216085028.htm
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Extracting precious zinc from waste ash
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Incineration of solid waste produces millions of tonnes of waste fly ash in Europe each year, that most commonly ends up in landfill. But this ash often contains significant amounts of precious metals, such as zinc. A unique method developed by researchers at Chalmers University of Technology, Sweden, can now help extract these precious metals, potentially leading to reductions in environmental pollution, landfill and transport.
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During waste incineration, the released flue gases are purified and the small particles present are separated, leading to the formation of fly ash. This fly ash contains toxic substances, such as dioxins, and so is normally classified as hazardous waste and landfilled. But it also contains valuable metals, such as zinc, which are thereby lost.But a new method from Chalmers University of Technology, tested at pilot scale and detailed over several years of research, involves treating this waste with an acid wash, also separated from the flue gases, to separate the zinc from the fly ash. The zinc can then be extracted, washed and processed into raw material."In our pilot study, we found that 70 percent of the zinc present in fly ash can be recycled. The zinc is not extracted as a pure metal, which would be a much more intensive process, but instead as a zinc-rich product, which can be sold to the metal industry and processed further in currently existing industry production lines," says Karin Karlfeldt Fedje, Associate Professor at Chalmers University of Technology, and researcher at the recycling and waste management company Renova AB.In further refinement to the method, the researchers have been able to significantly reduce the level of toxicity."After extraction, we incinerate the residual ash again to break down the dioxins. Ninety percent of this is then turned into bottom ash, which can be used as a construction material, for example," explains Karin Karlfeldt Fedje.Internationally, the prevalence of waste incineration is varied, but the need to handle large amounts of ash after the process is widespread. In Sweden, incineration of household waste in waste-to-energy plants is common, and results in around 250,000 tonnes of fly ash every year that could potentially be treated in this way. The rest of Europe accounts for around ten times that amount.Although it is hard to estimate how many tonnes of zinc are currently lost through landfill in Sweden and beyond, the method developed by the Chalmers researchers can be of great interest to all waste management actors. It offers great potential for recovering these metals in a relatively simple way and could have a significant impact on the profitability of waste incineration, as well as its role in the circular economy."The technology for extracting zinc from fly ash could have several positive effects, such as reducing the need for mining virgin zinc raw material, lower levels of toxicity in the ash, and greatly reduced landfill contributions. It can be a vital contribution to society's efforts towards a more circular economy," says Sven Andersson, Adjunct Professor at Chalmers and R&D Manager at flue gas cleaning supplier Babcock & Wilcox Vølund AB.Dividing her time between Chalmers and Renova, Karin Karlfeldt Fedje has spent many years developing the methodology, in collaboration with several external actors. Together with Sven Andersson, they have been able to design a full-scale process. Their research has led to Renova AB and B&W Vølund now building an ash washing facility with zinc recycling in Gothenburg Sweden, an investment that is estimated to save hundreds of thousands of euro every year for the municipally owned waste management company.
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Environment
| 2,020 |
December 15, 2020
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https://www.sciencedaily.com/releases/2020/12/201215140837.htm
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Urine diversion shows multiple environmental benefits when used at city scale
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Diverting urine away from municipal wastewater treatment plants and recycling the nutrient-rich liquid to make crop fertilizer would result in multiple environmental benefits when used at city scale, according to a new University of Michigan-led study.
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The study, published online Dec. 15 in the journal The researchers found that urine diversion and recycling led to significant reductions in greenhouse gas emissions, energy use, freshwater consumption and the potential to fuel algal blooms in lakes and other water bodies. The reductions ranged from 26% to 64%, depending on the impact category."Urine diversion consistently had lower environmental impacts than conventional systems," said lead author Stephen Hilton, who conducted the study for his master's thesis at U-M's School for Environment and Sustainability."Our analyses clearly indicate that the well-defined benefits -- reduced wastewater management requirements and avoided synthetic fertilizer production -- exceed the environmental impacts of urine collection, processing and transport, suggesting that further efforts to develop such systems are warranted."Urine contains the essential nutrients nitrogen, phosphorus and potassium and has been used as a crop fertilizer for thousands of years. In recent years, urine recycling has been studied as a way to produce renewable fertilizers while reducing the amount of energy and chemicals needed to treat wastewater.While no city-scale urine-diversion and recycling systems exist, several small-scale demonstration projects are underway, including one at U-M and a Vermont project led by the Rich Earth Institute. Hilton used data from both projects to model the likely environmental impacts of city-scale urine diversion and recycling.Wastewater treatment was a major focus of the study, and data from treatment plants in Michigan, Vermont and Virginia were used in the analysis. The Virginia plant is located in the Chesapeake Bay region and served as an example of treatment plants with strict requirements for nitrogen and phosphorus removal.Using a technique called life-cycle assessment, which provides a comprehensive evaluation of multiple environmental impacts, Hilton and his colleagues compared the performance of large-scale, centralized urine-diversion and fertilizer-production facilities to conventional wastewater treatment plants and the production of synthetic fertilizers using non-renewable resources.Urine diversion and recycling was the clear winner in most categories and in some cases eliminated the need for certain wastewater-treatment chemicals. On the downside, one method for making urine-derived fertilizer led to consistent increases in acidification.A few previous life-cycle assessments have compared the environmental impacts of urine recycling to conventional systems. But the new U-M study is the first to include detailed modeling of wastewater treatment processes, allowing the researchers to compare the amount of energy and chemicals used in each method."This is the first in-depth analysis of the environmental performance and benefits of large-scale urine recycling relative to conventional wastewater treatment and fertilizer production," said Greg Keoleian, senior author of the ES&T paper and director of the Center for Sustainable Systems at the U-M School for Environment and Sustainability. He also chaired Hilton's thesis committee.About half of the world's food supply depends on synthetic fertilizers produced from nonrenewable resources. Phosphate rock is mined and processed to make phosphate fertilizer. The production of nitrogen fertilizer is an energy-intensive process that uses natural gas and is responsible for 1.2% of world energy use and associated greenhouse gas emissions.At the same time, water and wastewater systems consume 2% of U.S. electricity, with nutrient removal being one of the most energy-intensive processes.Diversion of urine to recover and recycle nitrogen and phosphorus has been advocated as a way to improve the sustainability of both water management and food production. It has the potential to reduce the amount of energy and chemicals needed to treat wastewater while decreasing the flow of nutrients that fuel harmful algal blooms in lakes.However, large-scale diversion and recycling would require systems to collect and transport urine, process it into fertilizer, then ship the end product to customers. Each of those steps has environmental impacts.In 2016, U-M researchers were awarded a $3 million grant from the National Science Foundation to study the potential of converting human urine into safe crop fertilizer. The project is led by Nancy Love and Krista Wiggington of the U-M Department of Civil and Environmental Engineering and involves testing advanced urine-treatment methods and investigating attitudes people hold about the use of urine-derived fertilizers. Love is also a co-author of the new Environmental Science & Technology paper.As part of the NSF-funded effort, urine-diverting demonstration toilets were installed on U-M's North Campus, along with a lab where the urine is converted to fertilizer. Hilton, who was a dual-degree master's student at the U-M School for Environment and Sustainability and the Department of Civil and Environmental Engineering, used data from the project to help model a large-scale system that diverts urine to make fertilizer."These new findings are encouraging because they demonstrate the potential environmental benefits of large-scale urine-diversion and recycling systems, suggesting that we're on the right track and should continue to develop these technologies," said study co-author Glen Daigger, a U-M professor of civil and environmental engineering and a member of Hilton's thesis committee.Bowen Zhou, a former member of the U-M research team who is now at the University of Waterloo, is also an author of the ES&T paper. The research was supported by the National Science Foundation and the Water Research Foundation.
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Environment
| 2,020 |
December 15, 2020
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https://www.sciencedaily.com/releases/2020/12/201215131242.htm
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Plastics pose threat to human health, report shows
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Plastics contain and leach hazardous chemicals, including endocrine-disrupting chemicals (EDCs) that threaten human health. An authoritative new report, "Plastics, EDCs, and Health," from the Endocrine Society and the IPEN (International Pollutants Elimination Network), presents a summary of international research on the health impacts of EDCs and describes the alarming health effects of widespread contamination from EDCs in plastics.
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EDCs are chemicals that disturb the body's hormone systems and can cause cancer, diabetes, reproductive disorders, and neurological impairments of developing fetuses and children. The report describes a wealth of evidence supporting direct cause-and-effect links between the toxic chemical additives in plastics and specific health impacts to the endocrine system.Conservative estimates point to more than a thousand manufactured chemicals in use today that are EDCs. Known EDCs that leach from plastics and threaten health include bisphenol A and related chemicals, flame retardants, phthalates, per- and polyfluoroalkyl substances (PFAS), dioxins, UV-stabilizers, and toxic metals such as lead and cadmium. Plastic containing EDCs is used extensively in packaging, construction, flooring, food production and packaging, cookware, health care, children's toys, leisure goods, furniture, home electronics, textiles, automobiles and cosmetics."Many of the plastics we use every day at home and work are exposing us to a harmful cocktail of endocrine-disrupting chemicals," said the report's lead author, Jodi Flaws, Ph.D., of the University of Illinois at Urbana-Champaign in Urbana, Ill. "Definitive action is needed on a global level to protect human health and our environment from these threats."The Swiss Ambassador for the Environment, Franz Xavier Perrez, commented, "'Plastics, EDCs, and Health,' synthesizes the science on EDCs and plastics. It is our collective responsibility to enact public policies to address the clear evidence that EDC in plastics are hazards threatening public health and our future."In May, the Swiss Government submitted a proposal to the Stockholm Convention to list the first ultra-violet (UV) stabilizer, plastic additive UV-328, for listing under the Stockholm Convention. UV stabilizers are a common additive to plastics and are a subset of EDCs described in this report. The Stockholm Convention is the definitive global instrument for assessing, identifying, and controlling the most hazardous chemical substances on the planet.The need for effective public policy to protect public health from EDCs in plastics is all the more urgent given the industry's dramatic growth projections. Pamela Miller, IPEN Co-Chair, commented, "This report clarifies that the current acceleration of plastic production, projected to increase by 30-36% in the next six years, will greatly exacerbate EDC exposures and rising global rates of endocrine diseases. Global policies to reduce and eliminate EDCs from plastic and reduce exposures from plastic recycling, plastic waste, and incineration are imperative. EDCs in plastics are an international health issue that is felt acutely in the global south where toxic plastic waste shipments from wealthier countries inundate communities.""Endocrine-disrupting chemical exposure is not only a global problem today, but it poses a serious threat to future generations," said co-author Pauliina Damdimopoulou, Ph.D., of the Karolinska Institutet in Stockholm, Sweden. "When a pregnant woman is exposed, EDCs can affect the health of her child and eventual grandchildren. Animal studies show EDCs can cause DNA modifications that have repercussions across multiple generations."Report: The report by the Endocrine Society, the largest international group of scientists, physicians, and academicians working in the field of endocrinology, was produced in collaboration with chemical technical experts at the global environmental health network, IPEN (International Pollutants Elimination Network). The global group of authors includes top experts in the field: Jodi Flaws, Ph.D., (University of Illinois at Urbana-Champaign, US), Pauliina Damdimopoulou, Ph.D., (Karolinska Institutet, Sweden), Heather B. Patisaul, Ph.D., (North Carolina State University, US), Andrea Gore, Ph.D., (University of Texas at Austin, US), Lori Raetzman, Ph.D., (University of Illinois at Urbana-Champaign, US), and Laura N. Vandenberg, Ph.D., (University of Massachusetts Amherst, US).
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Environment
| 2,020 |
December 15, 2020
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https://www.sciencedaily.com/releases/2020/12/201215121205.htm
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Engineers go microbial to store energy, sequester carbon dioxide
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By borrowing nature's blueprints for photosynthesis, Cornell University bioengineers have found a way to efficiently absorb and store large-scale, low-cost renewable energy from the sun -- while sequestering atmospheric carbon dioxide to use later as a biofuel.
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The key: Let bioengineered microbes do all the work.Buz Barstow, assistant professor of biological and environmental engineering at Cornell University, and doctoral candidate Farshid Salimijazi have assembled theoretical solutions and models that calculate efficiency in microbes, which could take in electricity and store carbon dioxide at least five times more efficiently than photosynthesis, the process by which plants turn sunlight into chemical energy."Soon, we will be living in a world with plentiful renewable electricity," Barstow said. "But in order to bring the bountiful energy to the grid, we will need energy storage with a capacity thousands of times greater than we have today."The research, "Constraints on the Efficiency of Engineered Electromicrobial Production," was published in October in the journal Electromicrobial production technologies fuse biology and electronics so that energy gathered from wind, sun and water can get converted into renewable electricity in the form of energy-storage polymers (engineered microbes). Solving a storage problem, these microbes can be used on demand or to create low-carbon transportation fuels."We need think about how we can store energy for rainy days or for when the wind doesn't gust," he said, noting that battery or fuel-cell technology can take up a lot of space. "We need solutions on how to store this large amount of energy in a cheap and clean way."In the paper, the researchers suggest taking advantage of microbial electrosynthesis, in which incoming electrons are fed directly to an engineered microbe, which would convert carbon dioxide into non-carbon molecules. More research is necessary to determine the best microbes for the job.Postdoctoral researcher Alexa Schmitz, a member of Barstow's lab, said the engineered microbes both store energy and absorb carbon dioxide. The CO"While the hydrocarbon fuel would not be carbon negative, carbon neutrality is still very good in this case," Schmitz said. "For a lot of machinery or in aviation, society may still need low-density hydrocarbon fuels for that sector."That scenario is much better than carbon expansion, she said. "We want to be able to make low-carbon fuel without digging for oil or getting gas out of the ground," she said, "and then releasing the carbon into the atmosphere."The microbes act as an efficient microscopic fuel cell," said Barstow, a Cornell Atkinson fellow. "That's why we're offering this road map for the best ways to exploit this potential. More research is necessary to determine the best microbes for the job, as everything comes down to efficiency at the end of the day."
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Environment
| 2,020 |
December 15, 2020
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https://www.sciencedaily.com/releases/2020/12/201215090328.htm
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Proteins enable crop-infecting fungi to 'smell' food
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New research shows the same proteins that enable human senses such as smell also allow certain fungi to sense something they can eat.
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The UC Riverside study offers new avenues for protecting people from starvation due to pathogenic fungus-induced food shortages. Understanding how fungi sense and digest plants can also help scientists engineer fungal strains that are more efficient at producing biofuels.Newly published by the American Society for Microbiology journal Key to this conversion process are G proteins, which send signals from a cell's outer membrane into its nucleus."These proteins get information about what's outside the cell into what is essentially the brain of the cell, the nucleus, which in turn instructs the cell to produce a cocktail of cellulose-digesting enzymes," said study author and biochemistry doctoral student Logan Collier.To determine whether G proteins play a role in the ability of fungi to sense nearby cellulose, the researchers modified strains of a fungus called Neurospora crassa. Once the G proteins were mutated, Neurospora no longer had the ability to "see" that it was on cellulose.Neurospora is a filamentous fungus, which means it's made of thin tubes that extend and form a mesh as it grows. It plays a critical role in the environment, recycling carbon by consuming decaying plant matter and converting it into glucose.It is also closely related to pathogenic fungi that kill crops such as tomatoes and wheat. One related species also causes rice blast, which destroys enough rice to feed about 80 million people annually. Knowing how to interfere with G protein signaling in the fungus so it cannot detect its "food" could be crucial to stopping these kinds of infections."No one has previously examined every member of the signaling pathway, creating a model for how every all of the G proteins work together," said Katherine Borkovich, a UC Riverside microbiology and plant pathology professor, who led the study.Moving forward, the research team would also like to apply what they've learned to biofuel production."It does appear from our study that there are ways to modify the fungus to produce extra cellulose-digesting enzymes, which would make them more efficient at breaking down biofuel feedstocks," Collier said. Based on renewable sources like plants, biofuels can play a valuable role in reducing dependence on fossil fuels.
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Environment
| 2,020 |
December 14, 2020
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https://www.sciencedaily.com/releases/2020/12/201214164320.htm
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Salt-tolerant bacteria with an appetite for sludge make biodegradable plastics
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The United States generates seven million tons of sewage sludge annually, enough to fill 2,500 Olympic-sized swimming pools. While a portion of this waste is repurposed for manure and other land applications, a substantial amount is still disposed of in landfills. In a new study, Texas A&M University researchers have uncovered an efficient way to use leftover sludge to make biodegradable plastics.
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In the September issue of the journal "The price of raw materials to cultivate biopolymer-producing bacteria accounts for 25-45% of the total production cost of manufacturing bioplastics. Certainly, this cost can be greatly reduced if we can tap into an alternate resource that is cheaper and readily obtainable," said Kung-Hui (Bella) Chu, professor in the Zachry Department of Civil and Environmental Engineering. "We have demonstrated a potential way to use municipal wastewater-activated sludge and agri- and aqua-culture industrial wastewater to make biodegradable plastics. Furthermore, the bacterial strain does not require elaborate sterilization processes to prevent contamination from other microbes, further cutting down operating and production costs of bioplastics."Polyhydroxybutyrate, an emerging class of bioplastics, is produced by several bacterial species when they experience an imbalance of nutrients in their environment. This polymer acts as the bacteria's supplemental energy reserves, similar to fat deposits in animals. In particular, an abundance of carbon sources and a depletion of either nitrogen, phosphorus or oxygen, cause bacteria to erratically consume their carbon sources and produce polyhydroxybutyrate as a stress response.One such medium that can force bacteria to make polyhydroxybutyrate is crude glycerol, a byproduct of biodiesel manufacturing. Crude glycerol is rich in carbon and has no nitrogen, making it a suitable raw material for making bioplastics. However, crude glycerol contains impurities such as fatty acids, salts and methanol, which can prohibit bacterial growth. Like crude glycerol, sludge from wastewater also has many of the same fatty acids and salts. Chu said that the effects of these fatty acids on bacterial growth and, consequently, polyhydroxybutyrate production had not yet been examined."There is a multitude of bacterial species that make polyhydroxybutyrate, but only a few that can survive in high-salt environments and even fewer among those strains can produce polyhydroxybutyrate from pure glycerol," Chu said. "We looked at the possibility of whether these salt-tolerating strains can also grow on crude glycerol and wastewater."For their study, Chu and her team chose the Next, the team tested the growth and ability of Chu noted that by leveraging "
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Environment
| 2,020 |
December 14, 2020
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https://www.sciencedaily.com/releases/2020/12/201214123626.htm
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Benefits of renewable energy vary from place to place
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A new study from North Carolina State University finds that the environmental benefits of renewable power generation vary significantly, depending on the nature of the conventional power generation that the renewable energy is offsetting. The researchers hope the work will help target future renewable energy investments in places where they can do the most good.
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"For years, researchers have taken different approaches to try to assess the environmental benefits of renewable energy," says Harrison Fell, co-author of the study and an associate professor of energy economics at NC State. "The Energy Information Administration started releasing detailed data on renewable power generation in 2018, and we realized that we finally had an opportunity to address this issue using real-world data."Our study is the first to quantify emissions reductions from solar and wind generation relying on renewable generation data across a broad array of regions, while also accounting for electricity trade between regions," Fell says.For the study, researchers drew on data from regions spanning the contiguous 48 states from July 2018 through March 2020.The big takeaway from the study is that the environmental value of renewable energy varies significantly. In other words, one megawatt hour (MWh) of renewable power varies depending on where that power was generated."For example, one MWh of solar power produced in Florida reduces carbon dioxide emissions by about twice as much as one MWh of solar power produced in California," says Jeremiah Johnson, corresponding author of the study and an associate professor of civil, construction and environmental engineering at NC State. "That's because California already has a cleaner grid when compared to other regions. So offsetting an hour of conventional power generation in California reduces CO2 emissions less than offsetting an hour of conventional power generation in Florida."Why is that important?"In the near term, these findings give us insight into where we should target investments in renewable power in order to maximize the environmental benefits," Johnson says.But that wasn't the study's only finding.The researchers also found that environmental benefits often crossed regional lines. For example, renewable power generated in State A might be used to offset power generation in State B, meaning that State B might receive the environmental benefits of renewable power projects in State A."Right now, renewable energy is largely driven by policies that vary from state to state," Fell says. "Our work here highlights one reason that this is not a very efficient approach to energy policy. A federal approach to renewable energy policy would be better able to account for the interstate nature of energy production, energy consumption and environmental benefits."The researchers note that this study is effectively a snapshot of where the nation's power sector is right now, and that investments in renewable power are likely to continue."It will be interesting to see how the distribution of benefits changes as regions expand their sustainable energy infrastructure," Fell says.
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Environment
| 2,020 |
December 14, 2020
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https://www.sciencedaily.com/releases/2020/12/201214123520.htm
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One's trash, another's treasure: Fertilizer made from urine could enable space agriculture
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In extreme environments, even the most ordinary tasks can seem like unsurmountable challenges. Because of such difficulties, humanity has, for the most part, settled on grounds that were favorable for harvesting crops, herding cattle, and building shelters. But as we seek to expand the limits of human exploration, both on earth and in space, the people pioneering this search will undoubtedly face conditions that, for all intents and purposes, are not conducive to human habitation.
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One of the foremost challenges facing any intended long-term settlement, be it in the Antarctic or on Mars (perhaps in the near future), is achieving some degree of autonomy, to enable isolated colonies to survive even in the event of a catastrophic failure in provisioning. And the key to achieving this autonomy is ensuring food sufficiency and self-sustenance. Unsurprisingly, therefore, space agricultural technology is one of the research topics currently being undertaken by the Research Center for Space Colony at Tokyo University of Science. The researchers here hope to spearhead the technological development for safe and sustainable space agriculture -- with the aim of sustaining humans for a long time in an extremely closed environment such as a space station.To this end, an innovative study was conducted by a team of Japanese researchers led by Junior Associate Professor Norihiro Suzuki from Tokyo University of Science and published in the Realizing that farmers have used animal waste as fertilizer for thousands of years, as a rich source of nitrogen, Dr. Suzuki and his team have been investigating the possibility of manufacturing it from urea (the main component of urine), to make a liquid fertilizer. This would also simultaneously address the problem of human waste treatment or management in space! As Dr. Suzuki explains, "This process is of interest from the perspective of making a useful product, i.e., ammonia, from a waste product, i.e., urine, using common equipment at atmospheric pressure and room temperature."The research team -- which also includes Akihiro Okazaki, Kai Takagi, and Izumi Serizawa from ORC Manufacturing Co. Ltd., Japan -- devised an "electrochemical" process to derive ammonium ions (commonly found in standard fertilizers) from an artificial urine sample. Their experimental setup was simple: on one side, there was a "reaction" cell, with a "boron-doped diamond" (BDD) electrode and a light-inducible catalyst or "photocatalyst" material made of titanium dioxide. On the other, there was a "counter" cell with a simple platinum electrode. As current is passed into the reaction cell, urea is oxidized, forming ammonium ions. Dr. Suzuki describes this breakthrough as follows, "I joined the 'Space Agriteam' involved in food production, and my research specialization is in physical chemistry; therefore, I came up with the idea of 'electrochemically' making a liquid fertilizer."The research team then examined whether the cell would be more efficient in the presence of the photocatalyst, by comparing the reaction of the cell with and without it. They found that while the initial depletion of urea was more or less the same, the nitrogen-based ions produced varied both in time and distribution when the photocatalyst was introduced. Notably, the concentration of nitrite and nitrate ions was not as elevated in the presence of the photocatalyst. This suggests that the presence of the photocatalyst promoted ammonium ion formation.Dr. Suzuki states, "We are planning to perform the experiment with actual urine samples, because it contains not only primary elements (phosphorus, nitrogen, potassium) but also secondary elements (sulfur, calcium, magnesium) that are vital for plant nutrition! Therefore, Dr. Suzuki and his team are optimistic that this method provides a solid basis for the manufacture of liquid fertilizer in enclosed spaces, and, as. Dr. Suzuki observes, "It will turn out to be useful for sustaining long-term stay in extremely closed spaces such as space stations."Humans inhabiting Mars might still be quite a distant reality, but this study surely seems to suggest that we could be on a path to ensuring sustainability -- in space -- even before we actually get there!
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Environment
| 2,020 |
December 14, 2020
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https://www.sciencedaily.com/releases/2020/12/201214123453.htm
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Success in the Amazon: Reducing deforestation
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In 2006, Greenpeace launched a campaign exposing deforestation caused by soy production in the Brazilian Amazon. In the previous year, soy farming expanded into more than 1,600 square kilometers of recently cleared forests. The destruction, they said, had to stop.
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In response, major soy companies in the region reached a landmark agreement as signatories to the Amazon Soy Moratorium (ASM), pledging not to purchase crops grown on recently cleared land. Deforestation fell in the following years, but no one had measured the moratorium's aggregate impact.Now, assistant professor Robert Heilmayr and his colleagues at the University of Wisconsin Madison have quantified the ASM's effects and documented how it achieved its success. The researchers found that the agreement prevented thousands of square kilometers of deforestation over its first decade. What's more, the policy did not appear to hamper agricultural growth or push deforestation to other sectors or regions. The study, funded by the Gordon and Betty Moore Foundation and the Norwegian International Climate and Forest Initiative, appears in "Over one decade the ASM saved 18,000 square kilometers of forest," said Heilmayr, an environmental economist in the Environmental Studies Program and at the Bren School of Environmental Science & Management. "This is an area bigger than the state of Connecticut."Around the same time the Amazon Soy Moratorium was adopted, the Brazilian government was expanding its regulations against deforestation. The policies covered the legal Amazon, a larger administrative area that includes the Amazon biome and parts of the Cerrado biome -- a vast region of tropical forest and savannah southwest of the rainforest.Fortunately, the moratorium had three key features the team could use to distinguish its effects from these government actions: It went into effect in May 2006; it was restricted to the Amazon biome; and it applied specifically to land cleared for soy production. Heilmayr broke down how these factors directed the team's analysis. "We compared deforestation across ecological biomes after the adoption of the ASM, and across locations with different suitability for soy production, to isolate the impact of the ASM," he explained.The authors found a reduction in deforestation above and beyond what they could attribute to government policies alone. They estimate that between 2006 and 2016, deforestation in soy-suitable portions of the Amazon was 35% lower than what would have occurred without the ASM."Our study is important because, for the first time, we were able to control for other policies and factors outside the ASM to quantify its unique contribution to forest conservation," explained coauthor Holly Gibbs, associate professor at UW Madison.Scientists and conservationists were concerned the ASM might prompt soy farmers to begin planting in pastures, thereby pushing ranchers to clear more forest, essentially passing the buck to a different sector. However, the study suggests this did not happen. Gibbs explained it's likely due, at least in part, to similar campaigns aiming to stem deforestation in the cattle sector. These efforts began in 2008 and resulted in similar zero-deforestation agreements in the cattle industry. The team also saw little evidence that the ASM was pushing deforestation into the nearby Cerrado biome, though this risk continues to be a concern.Although some Brazilian policymakers worry that strict environmental commitments may weaken economic growth, soy production in the Amazon has continued to expand since adoption of the ASM. It increased from 4.9 million tonnes of production in 2006 to 17.2 million tonnes in 2019. Ultimately, the moratorium has demonstrated that soy expansion is possible without deforestation, Gibbs explained.To better understand how this type of conservation policy could be applied elsewhere, the team sought to pinpoint exactly what contributed to the moratorium's effectiveness. "One of the strengths of the Amazon Soy Moratorium is that it was a nearly unanimous decision among all the soy buyers in that sector," said Heilmayr. The signatories account for about 90% of all soy purchases in the region, and this high market share ensured that the agreement would transform agricultural practice. If farmers wanted to sell their soy, they'd have to abide by the policies it set out.Another factor that contributed to the ASM's success was the cooperation of private companies, non-profit NGOs and government agencies. Corporate participation adds a direct market penalty that discourages deforestation, Heilmayr explained. Meanwhile, the involvement of environmental organizations like Greenpeace, The Nature Conservancy and World Wildlife Fund boosts confidence that the agreement isn't merely a form of greenwashing. Finally, public investments in satellite monitoring systems and local property registries provide the backbone for monitoring and enforcing the moratorium. Heilmayr believes the interplay between businesses, NGOs and government actors has lent greater credibility to the initiative in the eyes of the global community.In 2016, the parties involved chose to renew the ASM indefinitely. While this represents a major victory for sustainable agriculture, the agreement's continuing success still faces obstacles. Some farmer representatives have raised objections to the ASM, saying that requirements that go beyond the country's forest laws amount to a violation of Brazil's sovereignty. However, the researchers note that the ASM also ensures that the Amazon soy sector maintains access to valuable international markets, according to industry trade groups, and at low cost to Amazon soy farmers."Very few Amazon soy farmers have land suitable for soy that they could clear in compliance with Brazil's Forest Code," said coauthor Lisa Rausch, a researcher at UW Madison. "The ASM really serves to reduce the incentives to clear land on non-soy farms and in unregistered areas for future soy production."The current political, economic and environmental zeitgeist highlights the benefits of the ASM's unique mix of public and private policymaking. Deforestation rates are now double what they were at their low point in 2012, though they're still dramatically lower than what they were back in 2003 and 2004. This uptick may reflect efforts by the Bolsonaro government to weaken the country's environmental protections.Heilmayr hopes "the interplay between private and public policymaking can make environmental gains more resilient -- consistent global demand for zero-deforestation soy will continue to discourage new deforestation despite the weakening of public policies."As a growing number of major companies pledge to reduce their environmental impacts around the world, the question arises of how to translate these lofty goals into concrete actions. "The ASM is a nice example of what is possible when companies take aggressive, transparent steps towards supply chain sustainability," Heilmayr said. "It provides hope that private actors can trigger meaningful improvements in the way society interacts with our environment."
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Environment
| 2,020 |
December 14, 2020
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https://www.sciencedaily.com/releases/2020/12/201214123451.htm
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Powerhouse plants that bolster the food web
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University of Delaware Professor of Entomology Doug Tallamy published a new research study in
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Why care about food webs? Well, these complex, highly interconnected systems of feeding relationships are essential for our planet's health. The Earth and its many species depend on them, including humans.To get the feast started, who has the first seat at the dining room table? The system all starts with plants, which get great publicity for their ability to convert carbon dioxide and into breathable air. But plants also have another, lesser known talent; they capture energy from the sun and turn it into food. Animals eat plants. Some eat plants directly; others obtain this energy by eating an animal who eats plants. And what animals are the best at converting this energy? Think small.Punching way above their weight class, insects are the best creatures on Earth at this energy transfer. And the world champions are caterpillars of the Lepidoptera species, the lifeblood of the food web whose protein-rich bodies are ideal for hungry birds.But caterpillars and other insects can't simply thrive among any plants; they must be surrounded by native plants, meaning those that have evolved alongside insects over millions of years. For example, caterpillars in Delaware like the promethea silkmoth don't jive with popular exotic trees like crepe myrtle, a popular choice by homeowners.And not just any native plant will do. The new research finds that only a few powerhouse plants support the majority of Lepidoptera. Ninety percent of what caterpillars eat is created by only 14 percent of native plant species with only five percent of the powerhouse plants taking credit for 75 percent of food. This pattern is consistent wherever you go in the U.S."Most people talk about a food chain as if it's linear. In a diagram, these connections look like a web rather than a simple chain," said Tallamy, a conservationist and bestselling author. "Take a keystone native plant like an oak tree. More than 500 types of caterpillars can eat that oak tree. That allows for a more complex and, thus, more stable food web."It's known that native plants are much better for an ecosystem than non-native plants, but this new study takes the knowledge an important further step."There are certain native plants, and there are actually not that many of them, that are doing the bulk of the work," said Tallamy. "So, if you build landscapes without these powerhouse plants that support caterpillars, the food web is doomed."The mid-Atlantic region boasts more than 2,000 plant genera; Tallamy and Narango categorized 38 as powerhouses. Native oaks, willows, birches and wild cherry trees made the trees' list; the most powerful herbaceous plants included goldenrod, asters and perennial sunflowers.Tallamy, a veteran of conservation research, was surprised by just how significant the difference was between powerhouse plants and other native species."The magnitude of the differences surprised us. It's not just a steady continuum where you have all of your native plants lined up and, from one plant to the next, there's a gradual decrease in productivity," said Tallamy. "It is extremely skewed toward these powerhouse plants."The Lepidoptera order of insects includes butterflies and moths. While butterflies are more admired for their beauty, the tastier moth caterpillars do most of the work of transferring energy to predators."You hear a lot about butterfly gardens. We need to think more about Lepidoptera gardens that include moths, who are the biggest driver of the food web," said Tallamy.Today, because of human expansion, pesticides and species isolation, insect populations around the world are in a precipitous decline, referred to as Insect Armageddon. Flying insects like moths have seen a 78% reduction over the past 40 years. Whether you love insects or run in fear of these six-legged invertebrates, their demise will affect you."Insects pollinate 90% of our flowering plants. Without insects, we'd lose these plants, which collapses the food web," said Tallamy. "We'd lose amphibians, reptiles, birds, mammals and even some freshwater fish."On top of their energy transfer abilities, insects are also crucial to soil decomposition, unlocking dead plant and animal material and returning nutrients to the soil. Sure, fungi and bacteria also have this talent, but they are significantly slower than insects. Tallamy puts it bluntly."If insect populations continue to decline, the Earth will rot. Humans will not survive such a drastic change," said Tallamy. "Insects are essential not just to our well-being, but to our continued existence on Earth."So, what can you do to help? As Tallamy details in his New York Times bestseller Nature's Best Hope: A New Approach to Conservation that Starts in Your Yard, homeowners can turn their yards into conservation corridors that provide wildlife habitats. They just need to choose plants native to their region."We need to change the cultural norms of what our yards should look like. Homeowners can shrink the size of their lawns," said Tallamy. "But you can't simply replace the grass with any old plants; choose key native plants that support local insect populations. If you're in the mid-Atlantic, pick from the 38 genera that we identified. Start with oaks. Some others on the list aren't the most beautiful, but we need to learn to accept that. Maybe you plant a black cherry in the backyard instead of out front."The same goes for public and non-profit efforts to restore ecosystems. Without powerhouse plants, restoration efforts will fall short."Think of a baseball team. What if you constructed a lineup of only pitchers and zero position players? They all pitch, but are lousy hitters, so you're going to lose the game," said Tallamy. "Take these national and international ventures [focused on forest restoration]. It's important to plant trees, but we need to have the right lineup of powerhouse plants native to each region."
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Environment
| 2,020 |
December 14, 2020
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https://www.sciencedaily.com/releases/2020/12/201214104713.htm
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Renewable energy: Frequency data for stable power supply
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In the renewable energies era, grid frequency will be an increasingly important indicator of stability of power supply. Under the direction of the Helmholtz Association, an interdisciplinary research consortium has analyzed frequency fluctuations in twelve synchronous grid areas on three continents. For data recording, scientists of Karlsruhe Institute of Technology (KIT) have developed a portable, GPS-synchronized recorder based on a new measurement technology. First results have now been published in
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Grid frequency and its fluctuations provide researchers of various disciplines with important information on the power grid. In particular, they reveal whether and to what an extent the grid is stable, i.e. whether supply and demand are balanced. Such data also allow conclusions with respect to effects of disturbances and breakdowns or the influence of power supplied from renewable energy sources. International experts in the areas of mathematics, physics, and engineering measured frequency data in Europe, the USA, and Africa and studied them in detail.For this big measurement campaign of about 430 days, a research team of KIT's Institute for Automation and Applied Informatics (IAI) developed a novel electrical data recorder (EDR) and provided the measurement teams with a device each. The EDR uses a GPS receiver for time synchronization and enables recording of raw and frequency data with very high resolution. The device is portable and can transmit raw data via a secure VPN tunnel directly to the "Large Scale Data Facility" of KIT's Steinbuch Centre for Computing, where they are further processed for research purposes. "Our recorder has a high performance and is easy to handle," says Dr. Heiko Maaß, IAI. To start measurements at a certain location, the EDR only needs to be plugged into a conventional power socket. If no Internet is available, data can be stored locally for several weeks.For the collaborative research projects, the devices have meanwhile traveled halfway round the world. The 1.27 gigabytes of frequency data from the 50 Hertz or 60 Hertz range used for the publication in The data produced by the EDR measurements will not only be used by the consortium, but also made available to the international community. "Our studies offer great potential -- not only for the development of statistical models on frequency dynamics, but also later on for a better regulation of power supply that is increasingly based on volatile sources of energy," says Professor Veit Hagenmeyer, Head of the IAI.
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Environment
| 2,020 |
December 14, 2020
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https://www.sciencedaily.com/releases/2020/12/201214104704.htm
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More frequent and extreme marine heatwaves likely to threaten starfish
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Common starfish cannot survive amplified marine heatwaves projected at the end of the century and experience lasting negative effects from current heatwaves, according to new research being presented on at the British Ecological Society's Festival of Ecology.
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In experiments simulating extreme ocean conditions, researchers at GEOMAR Helmholtz-Centre for Ocean Research Kiel found that heatwaves of +8 °C, projected by 2100, killed 100% of starfish tested. Heatwaves of this magnitude are only 1 degree warmer than heatwaves recorded in 2018 in the Kiel Fjord, where the research took place.They also found that present day heatwaves of +5 °C -- experienced in summer months -- negatively affected starfish feeding. If the heatwave was short, star fish were able to recover, but during extended heatwaves, starfish were unable to recover and lost weight.Fabian Wolf, who is presenting the research, said: "Our findings showcase that extreme environmental conditions such as marine heatwaves may temporally exceed a species tolerance limit with potential implications for populations at these shallow coastal depths."The researchers also tested the combined effects of other extreme events. In each treatment, heatwaves were followed by a simulated hypoxic upwelling event, a phenomenon where coastal water becomes colder, more saline, more acidic and higher in CO2.Fabian explains: "During spring and summer, plankton blooms (which often benefit from global warming) sink to the sea's bottom as dead material. Here, bacteria degrade this material, consuming oxygen and producing carbon dioxide. In coastal areas, particularly strong and persistent winds may push the surface water away from land, while deep (acidified and hypoxic water) is shoaled up the shores."The researchers found that starfish that didn't experience a heatwave were more affected by a subsequent hypoxic upwelling event, with a significant reduction in their activity. They propose that the first stressor, the heatwave, could provide resilience for the starfish that enables them to better cope with the second, the upwelling event."Our results emphasise that it is crucial to study different stressors in combination and not isolation as stressors naturally occur in succession, meaning that they are never independent of each other." said Fabian.Common starfish, which are found widely throughout the North-East Atlantic and are a familiar fixture of UK rockpools, are known as a keystone species, characterised by their high importance in the ecosystem. As a predator, common starfish prey on blue mussels and control their population size."If the common starfish is lost from a relatively species-poor system, blue mussels may grow uncontrolled and form monocultures. Other habitat-forming species like seagrass and seaweed could be lost in the process of blue mussel propagation." said Fabian."It must also be considered that other, non-native species may come and fill these gaps, as can be seen by several recently introduced crab species to the Western Baltic Sea that have blue mussels as their preferred prey."Even if common starfish are not killed outright by heatwaves, the researcher's findings that they lose weight in extended heatwaves could alter the prey they're able to eat. This is because starfish select prey based on its size comparative to them. If smaller starfish are only able to feed on juvenile blue mussels, populations might get older, impacting the ecosystem.The researchers ran the experiments in a state-of-the-art facility consisting of large experimental tanks, the Kiel Indoor Benthocosms at GEOMAR Helmholtz-Centre for Ocean Research Kiel. These specialist tanks allowed the researchers to apply upwelling conditions and heatwaves of varying intensity and duration over 63 days of total experimental time.To measure the effects these conditions had on the starfish, the researchers recorded their feeding rate (on blue mussels), their activity (time it took them the right themselves when tipped onto their backs) and weight change.The researchers acknowledge the limitations in drawing conclusions on whole ecosystem impacts. Fabian said: "The impacts of marine heatwaves and hypoxic upwelling events on the blue mussel prey were neglected from the present study, limiting the conclusions to a top-down effect."Yet, in mussel-dominated ecosystems prey populations will be highly controlled by starfish and any implication for their performance will translate into ecosystem-level impacts."In addition, this study does not factor in species behaviour in the natural environment. Starfish may avoid heated surface waters by moving to deeper water. But these waters may be hypoxic during summer months, shrinking their viable habitat.The researchers hope that future work will help to reveal the underlying physical mechanisms behind their findings, such as the production of special proteins which help starfish deal with heat stress.They also want to explore the impacts of extreme marine events on other species in coastal ecosystems. Fabian said: "Elucidating the overall impact of ocean change on mussel reefs may need to include all other predators in the system, and their responses to these simulated events."
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Environment
| 2,020 |
December 14, 2020
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https://www.sciencedaily.com/releases/2020/12/201210145705.htm
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Shedding new light on mysteries behind the light emission of fireflies
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A team of researchers from the NYU Abu Dhabi's (NYUAD) Smart Materials Lab (SML) led by Professor of Chemistry Panče Naumov has conducted a thorough review of the scientific literature surrounding the natural production of light, called bioluminescence, and developed conclusions that will help others in the field direct their research to uncover the mysteries behind this fascinating natural phenomenon.
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In the new study The Elusive Relationship Between Structure and Color Emission in Beetle Luciferases, which is featured on the cover of the journal The NYUAD researchers, including the Naumov group's post-doctoral associates César Carrasco-López and Stefan Schramm, and undergraduate student Nathan M. Lui, identify the intricate structural factors that govern what color light is emitted by wild-type and mutant luciferases, the enzymes that generate light. They also demonstrate that it is possible to build a library of bioluminescent enzymes in the future, which will enable researchers to control the color and intensity of light emission by engineering luciferases at will."Learning from nature will provide us with tools to engineer luciferases that can emit colors within a large range of energies," said Naumov. "This will eventually help us expand the range of application of these and similar enzymes for some exciting applications in biology and medicine, including early diagnosis and prevention of diseases."Throughout human's history, bioluminescence has been an inspiration to scientists, artists, and laypersons. Glowing fungi or ostracods have been used by tribes and soldiers as lanterns to guide their way through jungles without the need of electricity, and fireflies were used by miners as safety lights.The Nobel Prize in Chemistry in 2008 was awarded for the discovery of the green fluorescent protein, a bioluminescent protein found in the jellyfish Aequorea victoria. Today, bioluminescence is the basis for a great number of bioanalytical methods, such as cell imaging, cancer research, and control of food contamination, and a way to efficiently convert the energy stored in chemical bonds into light that can be easily detected. For example, bioluminescence of some bioluminescent bacterial strains is used to monitor water toxicity and contamination. The fluorescent proteins are genetically inserted into cells and animals to analyze important aspects of dynamics of some diseases.The latest research from the NYUAD's Naumov team is poised to solve some of the mysteries surrounding the chemistry of bioluminescence and to bring this research closer to applications.
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Environment
| 2,020 |
December 11, 2020
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https://www.sciencedaily.com/releases/2020/12/201211115501.htm
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Evolution of tropical biodiversity hotspots: Look to harsh species-poor areas
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For decades, scientists have worked to understand the intricacies of biological diversity -- from genetic and species diversity to ecological diversity.
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As they began to comprehend the depths of diversity across the planet, they noticed an interesting pattern. The number of species increases drastically from the poles to the equator. This phenomenon, known as the latitudinal gradient of species diversity, has helped define the tropics as home to most of the world's biodiversity. Scientists estimate that tropical forests contain more than half the species on earth, from plants and insects to birds, amphibians, and mammals.These biologically rich areas are known as biodiversity hotspots. To qualify as a hotspot, a region must have at least 1,500 vascular plants species occurring nowhere else and have 30 percent or less of its original natural vegetation. In other words, it must be both irreplaceable and threatened.While scientists agree that most biological diversity originated in the tropics, the jury is still out on how tropical species diversity formed and how it is maintained. A new study published in In "The evolution of tropical biodiversity hotspots," researchers argue that tropical species form faster in harsh species-poor areas but accumulate in climatically moderate areas to form hotspots of species diversity. Drawing on decades of expeditions and research in the tropics and the scientists' own knowledge and sampling of tropical bird diversity, the research team assembled a large and complete phylogenomic dataset for a detailed investigation of tropical diversification."This is our magnum opus," said Elizabeth Derryberry, associate professor in the University of Tennessee, Knoxville's Department of Ecology and Evolutionary Biology (EEB) and a senior author of the study. "This research is the product of a decades-long international collaboration to produce a completely sampled evolutionary history of a massive tropical radiation -- the 1,306 species of suboscine passerine birds."Roughly one in three Neotropical bird species is a suboscine, making it the predominant avian group in the Neotropic terrestrial habitat -- which ranges from the Andes snow line to the Amazon lowlands -- and a perfect group to shed light on the origins of tropical biodiversity."The tropics are a natural laboratory for speciation research," said Michael Harvey, a recent EEB postdoctoral student and lead author of the study. "Many high-profile studies over the years sought answers to fundamental questions concerning species formation and maintenance." These earlier projects, he added, sampled only a minority of the existing species within the group being studied. In addition, said Derryberry, data analysis limitations in nearly all of the previous studies left them open to estimation errors.For this study, Derryberry, Harvey, EEB Professor Brian O'Meara, and fellow researchers used a time-calibrated phylogenomic tree to provide information needed for estimating the dynamics of suboscine diversification across time, lineages, and geography. They also used the tree to test links between the dynamics and potential drivers of tropical diversity."We took no shortcuts in this study," Derryberry said. "We leveraged this unparalleled sampling of tropical diversity to illustrate the tempo and geography of evolution in the tropics. It is the first study to demonstrate conclusively that tropical biodiversity hotspots are linked to climates that are both moderate and stable."The team discovered that species-rich regions in the tropics contain diversity accumulated during a protracted evolutionary period. A key result of their study is that the best predictor of elevated speciation rates in North and South American suboscines is low species diversity. In other words, new species form at higher rates in areas containing relatively few species."The qualities that nurture diversity, lower extinction, and promote the gradual accumulation of species are, paradoxically, not the ones that support biodiversity hotspots," Harvey said. "The hotspots are seeded by species born outside the hotspot in areas characterized by more extreme and less climatically stable climates."The team discovered that, overall, extreme environments limit species diversity but increase opportunities for populations to evolve to become distinct species. Moderate climates, on the other hand, limit speciation but provide more opportunities for species diversity to accumulate."Our study will pave the way for future investigations of evolution in the world's diversity hotspots," Derryberry said. "This paper marks not only a change in our understanding of evolution in the tropics, but also in acknowledgement and valuation of the diversity of culture, expertise, and perspective in the field of ornithology."International collaboration for the study included researchers from Colombia, Brazil, Uruguay, and Venezuela as well as ornithologists from groups underrepresented in the sciences, include Latino and women researchers.
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Environment
| 2,020 |
December 11, 2020
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https://www.sciencedaily.com/releases/2020/12/201211083113.htm
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Mass extinctions of land-dwelling animals occur in 27-million-year cycle
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Mass extinctions of land-dwelling animals -- including amphibians, reptiles, mammals, and birds -- follow a cycle of about 27 million years, coinciding with previously reported mass extinctions of ocean life, according to a new analysis published in the journal
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The study also finds that these mass extinctions align with major asteroid impacts and devastating volcanic outpourings of lava called flood-basalt eruptions -- providing potential causes for why the extinctions occurred."It seems that large-body impacts and the pulses of internal Earth activity that create flood-basalt volcanism may be marching to the same 27-million-year drumbeat as the extinctions, perhaps paced by our orbit in the Galaxy," said Michael Rampino, a professor in New York University's Department of Biology and the study's lead author.Sixty-six million years ago, 70 percent of all species on land and in the seas, including the dinosaurs, suddenly went extinct, in the disastrous aftermath of the collision of a large asteroid or comet with the Earth. Subsequently, paleontologists discovered that such mass extinctions of marine life, in which up to 90 percent of species disappeared, were not random events, but seemed to come in a 26-million-year cycle.In their What could be causing the periodic mass extinctions on land and in the seas? Mass extinctions are not the only events occurring in cycles: the ages of impact craters -- created by asteroids and comets crashing to the Earth's surface -- also follow a cycle aligning with the extinction cycle.Astrophysicists hypothesize that periodic comet showers occur in the Solar System every 26 to 30 million years, producing cyclical impacts and resulting in periodic mass extinctions. The Sun and planets cycle through the crowded mid-plane of the Milky Way Galaxy about every 30 million years. During those times, comet showers are possible, leading to large impacts on the Earth. The impacts can create conditions that would stress and potentially kill off land and marine life, including widespread dark and cold, wildfires, acid rain, and ozone depletion."These new findings of coinciding, sudden mass extinctions on land and in the oceans, and of the common 26- to 27-million-year cycle, lend credence to the idea of periodic global catastrophic events as the triggers for the extinctions," said Rampino. "In fact, three of the mass annihilations of species on land and in the sea are already known to have occurred at the same times as the three largest impacts of the last 250 million years, each capable of causing a global disaster and resulting mass extinctions."The researchers were surprised to find another possible explanation beyond asteroids for mass extinctions: flood-basalt eruptions, or giant volcanic eruptions that cover vast areas with lava. All eight of the coinciding mass die-offs on land and in the oceans matched times of flood-basalt eruptions. These eruptions also would have created severe conditions for life, including brief periods of intense cold, acid rain, and ozone destruction and increased radiation; longer term, eruptions could lead to lethal greenhouse heating and more acid and less oxygen in the ocean."The global mass extinctions were apparently caused by the largest cataclysmic impacts and massive volcanism, perhaps sometimes working in concert," added Rampino.
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Environment
| 2,020 |
December 10, 2020
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https://www.sciencedaily.com/releases/2020/12/201210145817.htm
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Perovskite/silicon tandem solar cells on the magic threshold of 30% efficiency
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Solar cells consisting of two semiconductors with differing band gaps can achieve considerably higher efficiencies when used in tandem compared to the individual cells on their own. This is because tandem cells use the solar spectrum more efficiently. In particular, conventional silicon solar cells primarily convert the infrared components of light efficiently into electrical energy, while certain perovskite compounds can effectively utilise the visible components of sunlight, making this a powerful combination.
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In the beginning of 2020, a team headed by Prof. Steve Albrecht at the HZB broke the previous world record for tandem solar cells made of perovskite and silicon (28.0%, Oxford PV), setting a new world record of 29.15%. Compared to the highest certified and scientifically published efficiency (26.2% in DOI: 10,1126/science.aba3433), this is a giant step forward. The new value has been certified at Fraunhofer ISE and listed in the NREL chart. Now, the results have been published in the journal "29.15% efficiency is not only the record for this technology but is at the very top of the entire Emerging PV category in the NREL chart," says Eike Köhnen, PhD student on Albrecht's team and shared first author of the study. In addition, the new perovskite/silicon tandem cell is characterised by consistent performance during more than 300 hours under continuous exposure to air and simulated sunlight without being protected by encapsulation. The team utilised a complex perovskite composition with a 1.68 eV band gap and focussed on optimising the substrate interface.With partners from Lithuania (the group of Prof. Vytautas Getautis) they developed an intermediate layer of organic molecules that arrange themselves autonomously into a self-assembled monolayer (SAM). It consisted of a novel carbazole-based molecule with methyl group substitution (Me-4PACz). This SAM was applied to the electrode and facilitated the flow of the electrical charge carriers. "We first prepared the perfect bed, so to speak, on which the perovskite lays on," says Amran Al-Ashouri, who is also a member of Albrecht's team and shared first author of the study.The researchers then used a range of complementary investigation methods to analyse the different processes at the interfaces between perovskite, SAM, and the electrode: "In particular, we optimised what is called the fill factor, which is influenced by how many charge carriers are lost on their way out of the perovskite top cell," explains Al-Ashouri. While the electrons flow off in the direction of sunlight through the C60 layer, the "holes" move in the opposite direction through the SAM layer into the electrode. "However, we observed that the extraction of holes is much slower than electron extraction, which limited the fill factor," says Al-Ashouri. However, the new SAM layer considerably accelerated the hole transport and thus simultaneously contributes to improved stability of the perovskite layer.Through a combination of photoluminescence spectroscopy, modelling, electrical characterisation, and terahertz conductivity measurements, it was possible to distinguish the various processes at the interface of the perovskite material and to determine the origin of significant losses.Many partners were involved in the project, including Kaunas University of Technology/Lithuania, University of Potsdam, University of Ljubljana/Slovenia, University of Sheffield/UK, as well as the Physikalisch-Technische Bundesanstalt (PTB), HTW Berlin, and the Technische Universität Berlin, where Albrecht holds a junior professorship. The work on the individual perovskite and silicon cells took place in the HZB labs HySPRINT and PVcomB, respectively. "Each partner brought their own special expertise to the project, so we were able to achieve this breakthrough together," says Albrecht. The maximum possible efficiency is already within reach: the researchers analysed the two cells individually and calculated a maximum possible efficiency of 32.4% for this design. "We can certainly achieve over 30%," says Albrecht.
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Environment
| 2,020 |
December 10, 2020
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https://www.sciencedaily.com/releases/2020/12/201210112120.htm
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How seaweed-munching crabs could help save coral reefs
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Coral reefs are facing a steep decline today for many reasons, including climate change, overfishing, pollution, disease, and more. What's taking their place is lots and lots of seaweed. But researchers reporting in the journal
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"Experimentally increasing the abundance of large native, herbivorous crabs on coral reefs in the Florida Keys led to rapid declines in seaweed cover and, over the course of a year or so, resulted in the return of small corals and fishes to those reefs," says Mark Butler of Florida International University. "This opens up a whole new avenue for coral reef restoration."Butler and colleagues, including study first author Angelo "Jason" Spadaro, have been studying the coral reef and other habitats in the Florida Keys for more than 30 years. Butler's familiarity with the place helped his team to recognize the under-appreciated role of a little-known, mostly nocturnal Caribbean king crab to coral reef dynamics. This crab eats an impressive amount of seaweed at rates that rival all other Caribbean species of fish and invertebrates. They also eat seaweed that other species avoid.The only trouble? Caribbean king crabs aren't naturally present in large enough numbers to keep the seaweed under control. But, the researchers wondered, what if it were possible to boost their numbers? Could the crabs restore balance on the reef?The researchers put the idea to the test for the first time in 2014-2015 within 12 isolated patches of coral reef. The reefs were split into three groups: unmanipulated control reef, reefs stocked with crabs, and reefs on which divers scrubbed the reef to remove seaweed and algae before adding crabs.At the start, 85% of the reef was covered with seaweed and that didn't change a year later on the reef they left alone. The addition of crabs put a big dent in the seaweed, dropping it to less than 50% cover. And, in the final treatment in which reefs were scrubbed first, seaweed cover dropped by about 80%; scrubbing the reefs alone also reduced seaweed cover, but the effect was only short-term unless crabs were also introduced."When Jason showed me the results he had compiled from our first year of experiments, I couldn't believe it -- they looked too good," Butler says. "You should have seen the look on Jason's face when I said, 'Nobody will believe these results. We have to repeat the experiment for another year at another location.' Not exactly what a grad student wants to hear when trying to finish up! But we did it and the results were the same."The repeat experiment showed similarly impressive results. Crabs alone reduced seaweed cover by about 50%. By scrubbing the reef first, seaweed declined by about 70%.The findings show that herbivorous crabs can be used as another tool for coral reef restoration, augmenting the common approach of transplanting coral fragments onto degraded reefs, according to the researchers. In essence, they say, the crabs improve the habitat conditions for corals and fishes."One wonders what the tropics would be like without the mind-boggling complexity and beauty of shallow coral reefs," Butler says. "For example, the third longest barrier coral reef in the world that fringes the Florida Keys now has less than two percent coral cover. Conquering the challenge of climate change coupled with local reef restoration, like development of stocking programs for herbivorous crabs, are immediately necessary to reverse this decline. Our findings mean little if they don't result in tangible new restoration efforts."Already coral nurseries have been established to help restore the reef, Butler says. To put the new findings into action will require setting up nurseries to raise large numbers of crabs. The researchers report that they are now trying to find the needed resources to do exactly that.This work was supported by a NOAA-Nature Conservancy Community-Based Restoration Grant, a Garden Club of America Fellowship in Ecological Restoration, and a Paul Kirk Wetland Research Fellowship.
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Environment
| 2,020 |
December 9, 2020
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https://www.sciencedaily.com/releases/2020/12/201209170710.htm
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Toxic pollutants can impact wildlife disease spread
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Exposure to toxic pollutants associated with human activities may be influencing the spread of infectious diseases in wildlife, according to a new study from the University of Georgia. The findings, just published in the Royal Society journal
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Researchers led by Cecilia Sánchez, a postdoctoral associate in the Odum School of Ecology, built a mathematical model to explore how toxic substances affect wildlife health and mobility, and how those effects in turn influence wildlife populations and the risk of disease spillover to humans."We found that while exposure to infectious agents or contaminants on their own might not have large effects on wildlife populations, the combination of the two can be greater than the sum of the parts," said senior author Richard Hall, a faculty member in the Odum School and College of Veterinary Medicine. "And further, when we start to see wildlife population declines under landscape modification, that could actually be a precursor to increased risk of zoonotic spillover, the chance that these pathogens transmit from wildlife into domestic animals and people."Human activities like urban, industrial and agricultural development are increasingly altering landscapes across the globe. Among their impacts is the introduction of toxic pollutants including heavy metals and pesticides.At the same time, these human-altered landscapes often attract wildlife -- think of food sources like bird feeders, unsecured dumpsters and farm fields. This not only exposes wildlife to toxic substances, it also exposes people to wildlife and any diseases they may be carrying.To understand how all these factors interact, the researchers created a mathematical model based on flying foxes infected by a virus. In Australia, several species of these fruit-eating bats have moved into urban areas in growing numbers, attracted by fruiting and flowering trees planted in gardens and parks and in response to the loss of native forest habitat. They are also known to carry viruses harmful to domesticated animals and humans.For their model, Sánchez and her colleagues simulated a series of landscapes with varying proportions of contaminated versus pristine habitat.They assumed that in all cases exposure to toxicants reduced both survival and mobility of wildlife, but because these substances can have very different effects on hosts and pathogens, they explored three scenarios for transmission. In one, toxicants reduced pathogen transmission through mechanisms like killing off parasites. In another, toxicants increased pathogen transmission, for instance by suppressing host immune systems. The final scenario assumed that toxicants had no effect on transmission.For each of the landscapes and scenarios, they started off with a population of 50,000 animals, of which 100 were infected, and ran the model for the equivalent of 50 years. They then noted the resulting wildlife population size, level of infection and risk of spillover to humans.The results were sometimes surprising.One unexpected finding was that when there was only little contaminated habitat, the overall wildlife population size remained robust and even increased.Sánchez explained that in this situation, the contaminated habitat could be acting as a trap for the pathogen. Sick animals that move in to those locations might die there because of the combined effects of contaminants and infection."We found that if toxicant-contaminated habitats trap animals in those areas by reducing movement capacity, that can help reduce infection prevalence in the overall population by not allowing sick animals to return to pristine habitats to seed infections there," she said.When contaminated habitats predominated the landscape, however, the combination of toxicants and infection impacted a much larger number of animals, leading to wildlife population declines.Increasing the percentage of contaminated habitat also affected spillover risk, which reached its peak when roughly half the landscape was contaminated."When wildlife comes into areas where there are lots of domestic animals and humans, that sets the stage for the potential for cross-species transmission," said Hall. "And that can be exacerbated where those areas are toxicant-contaminated. So if we want to reduce spillover risk and reduce negative effects on wildlife, this really points to the importance of restoring pristine or native habitats for these species."Study co-author Sonia Altizer, the UGA Athletic Association Professor of Ecology, said that as human-dominated landscapes expand and intensify, animals are being stressed by multiple problems simultaneously."Because different stressors like pathogens and contaminants can interact in surprising ways, our study highlights the need for on-the-ground monitoring studies that can track how these interactions play out in real-world wildlife populations," she said.The research was supported by the ARCS Foundation and the National Science Foundation.
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Environment
| 2,020 |
December 9, 2020
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https://www.sciencedaily.com/releases/2020/12/201209170704.htm
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Big data offers promise of better groundwater management in California
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To ensure that California's groundwater is sustainably managed in the future and over the long-term, current state definitions of what constitutes groundwater may need to be revised, according to research published this week in
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The research shows that existing groundwater wells already penetrate and encroach upon the bases of fresh water that are used to define basin bottoms. In addition, brackish waters exist within current groundwater basins, and fresh water exists outside delineated groundwater basins. Brackish water, which was once deemed unusable, can now be used, thanks to technological advances. Finally, there are concerns about regulating groundwater on the basis of its quality rather than its usage, as is currently the case, since this provides a loophole for potential groundwater users who could drill deeper and skirt existing restrictions on freshwater pumping.Together, these findings suggest that groundwater may already be poorly safeguarded in some places and that the 'Base of Fresh Water' concept may need to be reconsidered as a means to define and sustainably manage groundwater in future."It is challenging for groundwater sustainability agencies to manage groundwater because this critical resource is not being sufficiently monitored," says Mary Kang, an Assistant Professor in McGill University's Department of Civil Engineering and the lead author on the study. An expert on groundwater issues, she has studied the topic in California since 2014. "The base of fresh water was historically set to protect high quality groundwater from oil and gas development. And we find that there is a mismatch between this base of fresh water and what the water quality data shows.""One component to managing groundwater sustainably is evaluating the physical resource within the context of its users," says Debra Perrone co-author of the study and Assistant Professor in UC Santa Barbara's Environmental Studies Program. "We evaluate the link between groundwater quality, particularly salinity, and groundwater users. We show that the current approach used to manage deep groundwater in some places may risk overlooking the complex realities pertaining to both groundwater salinity and groundwater users. For example, the data suggest that people are constructing groundwater wells deeper than the base of fresh water in some areas."In 2014, in response to repeated droughts, the state passed the Sustainable Groundwater Management Act (SGMA) to regulate groundwater for the first time in California's history. However, the effectiveness of this legislation is yet to be determined, as it relies upon administrative definitions of groundwater that are based on the extent of fresh water to define a vertical or three-dimensional groundwater basin for managing water."The Sustainable Groundwater Management Act currently only applies to fresh groundwater basins since administrative definitions of groundwater originated decades ago when it was economically infeasible to treat and distribute 'unusable' brackish or saline groundwater," says co-author Melissa Rohde, a scientist with The Nature Conservancy of California. Rohde is currently providing scientific support to advance the successful implementation of SGMA. "With technological advances, brackish water is now usable and increasingly desirable with declining access to fresh water. By excluding brackish groundwater from sustainable groundwater management, we run the risk of undermining SGMA and overexploiting this important public resource."
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Environment
| 2,020 |
December 9, 2020
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https://www.sciencedaily.com/releases/2020/12/201209170627.htm
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How soil fungi respond to wildfire
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In the wake of the 2017 North Bay fires, the golden hills of Santa Rosa, California, were unrecognizable. Smoky, seared and buried under ash, the landscape appeared desolate, save for some ghostly, blackened -- but still alive -- oak trees. For Stanford University graduate student, Gabriel Smith, whose family lives in Santa Rosa, the devastation was heartbreaking, but it also offered a unique scientific opportunity: a natural experiment on the effects of wildfires on the microbes that live in soil, which Smith studies in the form of fungi.
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So, Smith and his mother spent his winter break collecting soil samples from burned areas near trees in Santa Rosa's Trione-Annadel State Park and Hood Mountain Regional Park and Preserve. For comparison, they also gathered samples from unburned locations."I wanted to know how these ecosystems that, on the outside, looked so burned and so destroyed might have been affected at a level that is not so obvious -- the soil fungi that I study," said Smith, who is a member of the lab of Kabir Peay, an associate professor of biology in the School of Humanities and Sciences. Most people know soil fungi by their fruit -- mushrooms -- but there's much more to these organisms, both physically and functionally. Working alongside plant roots and other microbes that live in the soil, soil fungi play important roles in their ecosystems, including helping trees grow and aiding in decomposition.The research, which was published Dec. 9 in "There has been renewed interest in how climate change is influencing the frequency of fires and how that's going to affect fire-mediated ecological processes in California going forward," said Peay, who is senior author of the research. "So it's important to have specific details about how changes in the fire regimes in California, and the West Coast in general, are going to be influencing ecosystems."Oak woodlands benefit from fire to the extent that many parks, including Trione-Annadel, are treated with prescribed burns to keep their oaks healthy. Fire clears leaf litter and dead branches, creates improved conditions for some seeds, and controls insects and pathogens that might otherwise cause disease. Most importantly, fire can prevent other trees -- such as those found in evergreen forests -- from invading the oak forests. While mature evergreens can survive, and even benefit from, fires, encroaching seedlings may not.To understand how the 2017 fires altered soil fungal communities in these two ecosystems, Smith and his mother dug up the top 10 centimeters of soil from 12 sites in Trione-Annadel and six at Hood Mountain, with guidance from the California Park Service. While Smith was home for break, the samples had to be temperature regulated."We ended up filling not only my parents' fridge but also my grandmother's fridge and my aunt's fridge. We also rigged a top-loading chest freezer to keep the right temperature," said Smith, who is lead author of the research. "There was a great deal of family support that went into this research."Back at the Stanford lab, Smith and Lucy Edy, a co-term student in earth systems who worked on this project as part of the Stanford Biology Summer Undergraduate Research Program, determined what fungi resided in each sample through DNA analysis. What he found suggests that how fungal communities respond to fire belowground mirrors how other parts of their ecosystems respond to fire above ground."There was a much greater difference between the burned and unburned points in evergreen forests than there was in the oak woodland communities," said Smith. "We predicted there would be a difference between the two ecosystems, but the extent of that difference was actually more than we expected."It will take additional research to understand why this is the case, but the researchers hypothesize that part of the reason may be that the soil fungal community "resets" when it burns. This would mean that the soil fungi associated with the oaks have less time between fires to change from its reset form, and the evergreen soil fungi have longer, leading to the greater differences seen in the soil of burned and unburned evergreen forests.For much of the history of studying fungi, researchers had to depend on what they could see above ground, including mushrooms. But increased access to DNA sequencing has opened up the field, helping scientists detail the complex relationships between various soil microbes, plants and ecosystem functions. Still, many questions remain concerning the effects of microbial diversity in the soil -- for example, the consequences of losing half the population of one microbe versus two-thirds or all of it, and the net impact of losing microbes that could cause disease in certain plants in addition to losing microbes that benefit those plants."As fire regimes increase in intensity and frequency with climate change, we must understand the ecological responses of these ecosystems in order to determine our necessary responses in relation to them," said Edy, who is a co-author of the paper. "Fungal ecology is perhaps outside the realm of first consideration when people think about the impact of wildfire, but these below-ground microbial interactions fuel and sustain entire ecosystems."This project, born from terrible circumstances, will likely produce many more studies, like the seedling experiments, and further investigations into how the fungal communities in the oak woodlands withstand fire."This was not originally part of Gabriel's PhD project. He had the foresight to recognize that this is not just something that was interesting on a personal level, but also that there's nice intellectual potential here," said Peay. "Works like this can advance our understanding of how the changes we see in the soil might then play a role in changing what future ecosystem types look like."This research was funded by the National Science Foundation, the Sonoma County Mycological Association, the Stanford Biology Summer Undergraduate Research Program Fellowship and the US Department of Energy Office of Science.
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Environment
| 2,020 |
December 9, 2020
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https://www.sciencedaily.com/releases/2020/12/201209170355.htm
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Academy scientists describe 213 species in 2020
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This past year, researchers at the California Academy of Sciences added 213 plant and animal species to the tree of life, providing deeper insight into the rich biodiversity of our planet and helping to inform global conservation strategies. The new species include 101 ants, 22 crickets, 15 fishes, 11 geckos, 11 sea slugs, 11 flowering plants, eight beetles, eight fossil echinoderms, seven spiders, five snakes, two skinks, two aphids, two eels, one moss, one frog, one fossil amphibian, one seahorse, one fossil scallop, one sea biscuit, one fossil crinoid (or sea lily), and one coral. More than two dozen Academy scientists -- along with many more collaborators throughout the world -- described the new species.
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While the coronavirus has presented unique challenges this year for Academy scientists -- whose research typically involves expeditions or visits to scientific collections -- it has also underscored the importance of their work. "Unfortunately, the pandemic is a symptom of our broken relationship with nature," says Academy virologist and Chief of Science Shannon Bennett, PhD. "These newly described species represent one aspect of a growing collective effort to mend that relationship. By improving our understanding of Earth's biodiversity and bringing us more in touch with the natural world, each new species serves as an important reminder -- as does the pandemic -- of our vital role in protecting our planet's ecosystems."Below are thematic highlights from the 213 new species described by the Academy this past year. On January 7, 2021, there will be a virtual NightSchool event celebrating the new species, featuring several of the researchers who described them.For researchers interested in describing new species, there are few places more rich in taxonomic treasures than natural history collections like those found at the Academy. Colloquially known as a 'library of life,' the Academy's collections contain more than 46 million specimens representing many branches across the tree of life.Since describing species takes time and expertise, a number of specimens in our collections represent species unknown to science. Indeed, that was the case for a number of this year's new species, including the striking bush pit viper, Importantly, the specimens found in natural history collections span both time and space, providing baseline data for the geographic distribution of species at various points in the past. For example, the collections used by Academy Curator of Botany Frank Almeda, PhD, and visiting researcher Ricardo Pacifico for this year's newly described flowering plants in the genus Microlicia provide researchers with potential locations in Brazil where they might find living specimens. Once found in the wild, the locations can be cross-referenced with information from the archived specimens to paint a picture of how the plant's range has changed over time -- invaluable information when assessing the conservation status of the species.To gain a deeper knowledge of these changes, however, requires specimens collected on geologic timescales -- across millennia instead of centuries. Fortunately, fossils can provide these windows to the past."Fossils provide a unique opportunity to observe how past species, communities, and ecosystems have responded to environmental change," says Academy collections manager Christine Garcia, who described the fossil scallop Amber fossils can be particularly insightful since they often preserve features that other fossils do not, such as muscle tissue or plant matter. Using this additional information, Academy Research Associate Aaron Bauer, PhD, and his colleagues determined that the amber-trapped amphibian After running a genetic analysis on an unknown species of sea slug, Lynn Bonomo, an early-career researcher working with Academy Curator of Invertebrate Zoology Terry Gosliner, PhD, was skeptical of her results. "I thought I had messed up," she recalls. According to her analysis, the new nudibranch was a member of After double-checking the analysis and studying the internal morphology of the specimen, however, Gosliner confirmed the finding: While it is exciting for a new species to bounce between genera, it is not uncommon. Even experts can misidentify unfamiliar species if the organisms lack the typical morphology of one genus or present those of another. To untangle these twisted branches on the tree of life, researchers turn to gene sequencing technologies, like those used by Bonomo, which determine the relationships between species through mathematical analyses.In addition to morphology and genetics, researchers also use behavior to distinguish species. For example, when describing this year's new species of crickets, Academy Research Assistant David Weissman, PhD, partially relied on analyses of the insects' chirps. Using recording equipment and audio software, entomologists like Weissman capture the sound waves of cricket calls to compare with those of known species.For some species, technology not only plays a significant role in how they are described but also how they are discovered. At up to 500 feet (approximately 150 meters) below the ocean's surface, mesophotic coral reefs pose challenges for conducting scientific research. Using traditional scuba gear to study these reefs would be impossible due to the intense pressure at such depths and the long duration necessary to reach them.To overcome these oceanic obstacles, scientists at the Academy use revolutionary diving technologies. Closed-circuit rebreathers scrub the carbon dioxide from exhaled breaths, then return oxygenated air mixed with helium to the diver so they can observe beautiful new species, such as this year's Together these innovative technologies -- gene sequencing, sound analysis, deep-sea diving equipment, and more -- allow researchers to explore the biodiversity of our world like never before, adding both species and clarity to the tree of life.Despite decades of scouring the Earth, it is estimated that more than 90% of species remain unknown to science. More humbling still, a number of the newly described species each year -- including an inconspicuous pipefish -- are found hidden in plain sight.Off the coast of Botany Bay, Australia, a popular scuba diving site near Sydney, pipefish have long been known to exist in the shallows among seagrass or brown algae, hiding from would-be predators. Until Research Associate Graham Short, PhD, discovered In addition to cryptic behavior driven by evolution, another explanation for finding undescribed species in familiar places is human encroachment on nature. As major cities like Guwahati, India -- home to the newly described gecko Though urban expansion can be ecologically disruptive, community outreach can inspire appreciation for the species that still call concrete jungles home. Indeed, part of Research Associate Aaron Bauer's motivation for naming the gecko From urban spaces to unexpected places, understanding biodiversity -- particularly where humans and nature coexist and therefore where nature is most vulnerable -- is crucial for effectively stewarding the planet. By continuing to scour the known for the unknown, researchers can deepen that understanding and further foster an appreciation for the natural world.
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Environment
| 2,020 |
December 9, 2020
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https://www.sciencedaily.com/releases/2020/12/201209124957.htm
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Innovation in novel hybrid energy systems
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Future novel hybrid energy systems could lead to paradigm shifts in clean energy production, according to a paper published last week in
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Researchers from the U.S. Department of Energy's (DOE's) three applied energy laboratories -- Idaho National Laboratory (INL), the National Renewable Energy Laboratory (NREL) and the National Energy Technology Laboratory (NETL) -- co authored the paper describing such integrated energy systems.Their effort outlines novel concepts to simultaneously leverage diverse energy generators -- including renewable, nuclear, and fossil with carbon capture -- to provide power, heat, mobility and other energy services. The historic collaboration between the nation's Nuclear Energy, Renewable Energy and Fossil Energy labs aims to address a grand national challenge from an objective, holistic perspective."The design of integrated energy systems is a significant challenge -- and opportunity," INL Director Mark Peters, Ph.D., said. "The collaboration by the three applied national laboratories, and the setup and operation of real-world experiments at their testing facilities, represents a comprehensive and focused effort that is transparent and objective. This work will help realize future advanced energy systems that should help our nation expand affordable energy options and significantly contribute to wide-scale decarbonization efforts."The new article presents an objective new framework for engineering-based modeling and analysis to support complex optimization of energy generation, transmission, services, processes and products, and market interactions.In short, it outlines a viable path forward for hybrid energy systems. Such systems are capable of leveraging multiple energy sources to maximize the value of each. They do this by creating higher-value products, delivering lower-emission energy to industry, and better coordinating demand with energy production."Working together, researchers at the nation's applied energy laboratories have identified critical synergies among different power generation sources, which will be vital to transforming our energy economy. We look forward to advancing these creative solutions, collaboratively," said Martin Keller, Ph.D., director of NREL.The paper describes one example of the multi-input, multi-output nature of these systems: a hypothetical, tightly coupled industrial energy park that uses heat and electricity from highly flexible advanced nuclear reactors, small-scale fossil generators, and renewable energy technologies to produce electricity and hydrogen from electrolysis."In this scenario, depending on market pricing, electricity and or heat could be sold into the grid, used on-site or stored for later distribution and use," said David C. Miller, Ph.D., NETL's senior fellow for strategic systems analysis & engineering and co-author of the article. "Furthermore, the output streams could also be used to produce hydrogen or other valuable chemicals and products."This flexibility could provide an abundant supply of clean energy for a larger net-zero-emission energy system. Such systems could support sectors of the economy that are more difficult to decarbonize, such as industry and transportation."Considering complementary attributes among various energy technologies opens up new opportunities for asset use optimization that meet multiple energy services and maximize economic value," said Douglas Arent, Ph.D., NREL's executive director, strategic public-private partnerships and the study's lead author.Groundwork for the article began in 2018, when NETL, NREL and INL hosted the first tri-lab workshop in response to DOE Deputy Secretary Mark Menezes' call for more coordinated work across the DOE applied energy labs. Building off knowledge gained during that collaboration, a focused workshop was held in April 2019 on the priority topic Modeling & Analysis of Current & Future Energy Systems. A third tri-lab workshop, held July 31-Aug. 1, 2019, focused on addressing the science and technology challenges associated with the design, development and deployment of new and advanced materials and components that will enable integrated hybrid energy systems."The National Energy Technology Laboratory is proud to partner with INL and NREL in this foundational work," NETL Director Brian J. Anderson, Ph.D., said. "The complimentary expertise across the three labs are bringing revolutionary ideas to the table on how to design and optimize integrated energy systems of the future."As illustrated by the NETL-NREL-INL research to date, the design of hybrid energy systems will require input from experts across the spectrum of energy research. To this end, the body of work by the three applied national laboratories, including the tri-lab workshops and the recent "The national laboratories offer a diversity of expertise that will allow us to achieve effective, cross-sector collaboration that is necessary to solve the true energy and environment grand challenges of our time," said Shannon Bragg-Sitton, Ph.D., INL lead for integrated energy systems and co-author of the article.
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Environment
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December 9, 2020
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https://www.sciencedaily.com/releases/2020/12/201209124945.htm
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Regions in Europe at risk of nitrate leaching
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Nutrient contamination of groundwater as a result of nitrogen-based fertilisers is a problem in many places in Europe. Calculations by a team of scientists led by the UFZ have shown that over a period of at least four months per year, nitrate can leach into the groundwater and surface water on about three-quarters of Europe's agricultural land. The proportion of areas at risk from nitrate leaching is thus almost twice as large as previously assumed.
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In agriculture, nitrogen-based fertilisers are often not applied in a way that is appropriate to the location and use. If the level is too high, the plants do not fully take up the nitrogen. As a result, the excess nitrogen is leached into the groundwater and surface water as nitrate -- a problem that occurs in several EU countries. For example, in 2018, the European Court of Justice (ECJ) condemned EU countries including Germany for breaching the EU Nitrates Directive. Last year, the EU Commission reminded Germany to implement the ECJ ruling.How much of the nitrogen applied through fertilisation can enter the groundwater and surface water as nitrate or is denitrified (i.e. converted to molecular nitrogen and nitrogen oxides and released into the air) depends, among other things, on complex processes in the soil. A team of UFZ researchers and U.S. partners led by hydrologist Dr Rohini Kumar have now analysed in more detail which processes determine the fate of excess nitrogen. The focus is on hydrological and biogeochemical processes in the root zone (i.e. the area that extends from the surface of the soil down to a depth of one meter). "The root zone is the most dynamic and active part of the subsoil, where soil moisture, evaporation and dry/wet phases prominently take effect," says Kumar. It acts as both a hydroclimatic and biogeochemical filter between the surface and the deeper subsurface layers.The vulnerability of agricultural land to nitrate leaching has so far been described using static information on land use, soils, and the topography of the landscape, combined with mean precipitation and groundwater levels -- without taking into account of their temporal variability. "However, precipitation and temperatures change daily. This affects evaporation and soil water and ultimately the retention time and water transport to deeper layers. Mean values, as used to describe the static condition, are therefore less appropriate from today's perspective," explains Kumar. The researchers therefore use a dynamic approach to calculate how long the dissolved nitrate could remain in the root zone before it leach down to deeper levels. They combine the mHM (mesoscale hydrologic model) developed at the UFZ with calculations of the daily change of water retention and nitrate in the root zone as well as denitrification. With the help of the mHM, scientists can simulate the spatio-temporal distribution of hydrological dynamics as well as transport dynamics occurring in the root zone throughout Europe to the day for the past 65 years.With the new approach, the UFZ researchers conclude that for at least four months per year, almost 75% of Europe's agricultural land is vulnerable to nitrate leaching into groundwater and surface waters. If the static approach is used, this proportion is only 42%. "Because the spatial-temporal dynamics of water transport have not been taken into account in the vulnerability assessment of delimiting nitrate vulnerable zones, the spatial extent of nitrate vulnerable areas is grossly underestimated," concludes co-author and UFZ hydrogeologist Dr Andreas Musolff. This concerns, among others, areas in the east and north-east of Germany, the Iberian Peninsula, and some Eastern European countries.According to the UFZ researchers, the new findings could better aid to risk management of nitrogen in agriculture. "Farmers could use the more precise information to more precisely adjust their fertiliser regimes, thereby ensuring that as little nitrate as possible is present in the soil during the particularly critical months," says Musolff. This would prevent additional nitrate from entering the groundwater and surface waters. "This study focussing on the soil zone is a starting point for a comprehensive risk assessment of nitrate loads in the groundwater and surface water. It will be followed by further research on transport and denitrification in the subsoil, groundwater and the surface-waters," says Kumar.
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Environment
| 2,020 |
December 9, 2020
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https://www.sciencedaily.com/releases/2020/12/201209124933.htm
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'Sparkling' clean water from nanodiamond-embedded membrane filters
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Although most of the planet is covered by water, only a fraction of it is clean enough for humans to use. Therefore, it is important to recycle this resource whenever possible. Current purification techniques cannot adequately handle the very hot wastewater generated by some industries. But now, researchers reporting in
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Some oil recovery methods and other industrial processes result in hot wastewater, which requires energy-intensive cooling before it can be purified through traditional reverse osmosis membranes. After purification, the water then needs to be heated before it can be re-used. At such high temperatures, traditional reverse osmosis membranes filter slowly, allowing more salts, solids and other contaminants to get through. Researchers have embedded extremely tiny nanodiamonds -- carbon spheres produced by explosions in small, closed containers without oxygen present -- onto these membranes in previous studies. Although the membranes effectively and quickly filtered large volumes of water and can protect against fouling, they were not tested with very hot samples. To optimize the membranes for use with hot wastewater, Khorshidi, Sadrzadeh and colleagues wanted to modify the nanodiamond spheres and embed them in a new way.The team attached amines to nanodiamonds and bathed them in an ethyl acetate solution to prevent the spheres from clumping. Then, a monomer was added that reacted with the amines to create chemical links to the traditional membrane base. Synergistic effects of the amine links and the ethyl acetate treatment resulted in thicker, more temperature-stable membranes, contributing to improvements in their performance. By increasing the amount of amine-enhanced nanodiamonds in the membrane, the researchers obtained higher filtration rates with a greater proportion of impurities being removed, even after 9 hours at 167 F, when compared to membranes without nanodiamonds. The new method produced membranes that could more effectively treat wastewater at high temperatures, the researchers say.
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Environment
| 2,020 |
December 9, 2020
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https://www.sciencedaily.com/releases/2020/12/201209115159.htm
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New blended solar cells yield high power conversion efficiencies
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Researchers at Hiroshima University in Japan have blended together various polymer and molecular semiconductors as photo-absorbers to create a solar cell with increased power efficiencies and electricity generation. These types of solar cells, known as organic photovoltaics (OPV), are devices that generate electricity when light is incident upon their photo-absorbers. The efficiency of a solar cell is determined by comparing how much electricity is generated to how much light is incident upon the cell. This is referred to as "photon harvest," or how many particles of light are converted into electrical current. The more efficient the solar cell, the more cost effective and pragmatic the cell is for commercial use.
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The team at the Graduate School of Advanced Science and Engineering added only a small amount of a compound that absorbs long wavelengths of light resulting in an OPV that was 1.5 times more efficient than the version without the compound. The compound was able to enhance the absorption intensity due to the optical interference effect within the device. The group went on to show that how they are distributed is key to further improved power generation efficiency."The addition of a very small amount of a sensitizer material to an OPV cell, which consists of a semiconducting polymer that we developed previously and along with other materials," said Itaru Osaka, corresponding author of the paper, published November 2020 in "This leads to a significant increase in the photocurrent and thereby the power conversion efficiency due to the amplified photon absorption that originates in the optical interference effect. A key is to use a very specific polymer, one that allows us to have a very thick semiconductor layer for OPV cells, which significantly enhances optical interference effect compared to a thin layer."As for future work, Osaka has his eyes set on pushing the boundaries of state of the art solar cells."Our next step is to develop better semiconducting polymers as the host material for this type of OPV and better sensitizer materials that can absorb more photons in the longer wavelength regions. This would lead to the realization of the world's highest efficiency in OPV cells."
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Environment
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