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Marine Conservation
and Sustainability,
a section of the journal
Frontiers in Marine Science
Received: 25 November 2020
Accepted: 30 June 2021
Published: 23 July 2021
Citation:
Rodemann JR, James WR,
Santos RO, Furman BT, Fratto ZW,
Bautista V, Lara Hernandez J,
Viadero NM, Linenfelser JO, Lacy LA,
Hall MO, Kelble CR, Kavanagh C and
Rehage JS (2021) Impact of Extreme
Disturbances on Suspended
Sediment in Western Florida Bay:
Implications for Seagrass Resilience.
Front. Mar. Sci. 8:633240.
doi: 10.3389/fmars.2021.633240
Impact of Extreme Disturbances on
Suspended Sediment in Western
Florida Bay: Implications for
Seagrass Resilience
Jonathan R. Rodemann1
*, W. Ryan James2
, Rolando O. Santos2
, Bradley T. Furman3
,
Zachary W. Fratto4
, Valentina Bautista1
, Jan Lara Hernandez1
, Natasha M. Viadero1
,
Joshua O. Linenfelser1
, Lulu A. Lacy1
, Margaret O. Hall3
, Christopher R. Kelble5
,
Christopher Kavanagh4 and Jennifer S. Rehage2
1 Department of Earth and Environment, Florida International University, Miami, FL, United States, 2
Institute of Environment,
Florida International University, Miami, FL, United States, 3 Florida Fish and Wildlife Conservation Commission, Florida Fish
and Wildlife Research Institute, St. Petersburg, FL, United States, 4 South Florida Natural Resources Center, National Park
Service, Homestead, FL, United States, 5 Atlantic Oceanographic and Meteorological Laboratory, National Oceanic
and Atmospheric Administration, Miami, FL, United States
Seagrasses are threatened worldwide due to anthropogenic and natural disturbances
disrupting the multiple feedbacks needed to maintain these ecosystems. If the
disturbance is severe enough, seagrass systems may undergo a regime shift to a
degraded system state that is resistant to recovery. In Florida Bay, Florida, United States,
two recent, large-scale disturbances (a drought-induced seagrass die-off in 2015 and
Hurricane Irma in 2017) have caused 8,777 ha of seagrass beds to degrade into a
turbid, unvegetated state, causing a large sediment plume. Using satellite imagery
digitization and long-term seagrass cover data, we investigate the expansion of this
sediment plume between 2008 and 2020 and the potential interaction of this sediment
plume with seagrass recovery in two focal basins in Florida Bay affected by the dieoff, Johnson and Rankin. The average size of the sediment plume increased by 37%
due to the die-off and Hurricane Irma, increasing from an average of 163.5 km2 before
the disturbances to an average of 223.5 km2
. The expansion of the plume was basinspecific, expanding into Johnson after the 2015 seagrass die-off with expansive and
long-lasting effects, but only expanding into Rankin after Hurricane Irma with less severe
and short-term effects. Furthermore, the sediment plume was negatively correlated with
seagrass cover in Johnson, but held no relationship with seagrass cover in Rankin.
Thus, different disturbances can act upon seagrass ecosystems at varying scales
with varying consequences. This study illustrates the advantage of combining satellite
imagery with field data to monitor disturbances as well as highlights the importance of
investigating disturbances of seagrass ecosystems at various scales to comprehend
seagrass resilience in the context of future extreme events.
Keywords: seagrass, suspended sediment, disturbance, resilience, Florida Bay, Everglades, seagrass die-off,
Hurricane Irma
Frontiers in Marine Science | www.frontiersin.org 1 July 2021 | Volume 8 | Article 633240
Rodemann et al. Sediment Plume and Seagrass Resilience
INTRODUCTION
Seagrass communities are a vital part of coastal ecosystems
worldwide, providing many ecosystem services such as carbon
storage (Mcleod et al., 2011; Fourqurean et al., 2012; Duarte
et al., 2013), habitat for fish and other fauna (Gillanders, 2006;
Unsworth et al., 2019), sediment stabilization (Bos et al., 2007),
and primary production (Duarte and Chiscano, 1999). However,
seagrasses around the world are declining due to anthropogenic
and natural disturbances, threatening the balance of these shallow
water ecosystems (Orth et al., 2006; Waycott et al., 2009). One of
the main causes of seagrass decline is the disruption of natural
feedbacks that promote seagrass growth and sustenance (Duarte,
2002; Orth et al., 2006). Stabilizing feedbacks (i.e., negative
feedback loops) control seagrass ecosystems at multiple scales
(Maxwell et al., 2017; O’Brien et al., 2017), from supporting
mesograzer populations at the meter scale (Valentine and Duffy,
2006; Duffy et al., 2015) to genetic diversity at the ecosystem
scale (Procaccini et al., 2007; Reynolds et al., 2013). For example,
grazing by sea urchins results in the reduction of aboveground
seagrass biomass, which increases the predation pressure on sea
urchins. The predation pressure leads to a decrease in urchin
population, thus allowing for the seagrass to recover (Heck
and Valentine, 1995). External disturbances can result in the
disruption of one or more of these stabilizing feedbacks, creating
destabilizing feedbacks (i.e., positive feedback loops) that drive
seagrass decline (Nyström et al., 2012; Maxwell et al., 2017;
O’Brien et al., 2017). An example of a destabilizing feedback is
the decline of seagrass, which increases sediment resuspension
events. The water column becomes more turbid, which in turn
lowers the light available for photosynthesis and leads to further