SYMP 4-2 - Carbon cycle science in the Florida Coastal Everglades: Research to inform carbon and water management

Tuesday, August 9, 2016: 8:30 AM
Grand Floridian Blrm B, Ft Lauderdale Convention Center
Tiffany G. Troxler1, Evelyn E. Gaiser2, Sean P. Charles3, Carlos Coronado4, Stephen Davis5, Jose Fuentes6, Stephen Kelly4, John S. Kominoski3, Christopher J. Madden4, Viviana Mazzei7, Fred H. Sklar8, Shelby Servais7, Joseph Stachelek4 and Benjamin J. Wilson7, (1)Southeast Environmental Research Center, Florida International University, Miami, FL, (2)Southeast Environmental Research Center (SERC), Florida International University, Miami, FL, (3)Florida International University, Miami, FL, (4)South Florida Water Management District, West Palm Beach, FL, (5)Everglades Foundation, (6)Department of Meteorology, Pennsylvania State University, (7)Biological Sciences, Florida International University, Miami, FL, (8)Everglades Systems Assessment Section, South Florida Water Management District, West Palm Beach, FL

Organic carbon (C) storage in peat soils is critical to maintaining wetland elevation and coastal wetland

stability. As sea level rises, coastal freshwater and brackish wetlands like the southern coastal

Everglades are being exposed to increased duration and spatial extent of inundation and salinity, which

can affect soil C balance through soil redox potential, microbial respiration, and the intensity of osmotic

stress to vegetation. The term “peat collapse” has been used to describe a relatively dramatic shift in soil

C balance, leading to a rapid loss of soil elevation, and culminating in a conversion of vegetated

freshwater marsh to open water. Evidence of freshwater peat collapse has been observed in lower Shark

River Slough, Everglades, Florida, suggesting that this process is ongoing and may be affected by factors

of reduction in freshwater discharge, recent storm surges (e.g., Hurricane Wilma), sea level rise, and

possibly fire. The process has been documented to varying degrees across the U.S., contributing to

instability of coastal marshes and degradation of important ecosystem services including fisheries habitat,

shoreline stabilization, and C sequestration provided. In field and mesocosm experiments, we are increasing

salinity in freshwater and brackish marshes of the southern coastal Everglades, to investigate auto- and

heterotrophic mechanisms hypothesized to contribute to peat collapse. Long-term research on primary

productivity illustrates interactions with water management and climate to influencing coastal wetland carbon cycling.


Evidence from our previous experiments with mangrove peats showed

predicted shifts in soil redox and enhanced C loss from soils exposed to increased salinity. 

Results from our marsh studies show reduction in phosphorus and increase in C acquisition by soil

microbes in brackish marshes, which become stronger C sources during the dry season than freshwater

marshes. Long-term field research illustrates the interaction of water management and soil carbon stability,

linking carbon and water management across the landscape. Our experimental studies will elucidate plant-soil

mechanistic responses to elevated salinity that are hypothesized to stimulate loss of soil C in the coastal Everglades.

Our long-term research provides the landscape context for how water management drives primary productivity,

vegetation change and ecosystem carbon cycling.