Coastal wetlands perform essential ecosystem functions that may become impaired when wetlands deteriorate from anthropogenic impacts. The Tolomato River estuary, part of the Guana Tolomato Matanzas National Estuarine Research Reserve (GTMNERR) on the east coast of Florida (USA), is bordered by vast coastal wetlands dominated by Spartina alterniflora. Dead oyster rakes have formed along the boundary between the wetlands and river in some areas. The effect of oyster rakes on wetland health is unknown. Some wetlands appear healthy with consolidated soil (i.e., “stable”), but others appear unhealthy with reduced plant vigor and loose, unconsolidated soil (i.e., “unstable”). This study hypothesized soil biogeochemical properties and processes will differ between stable and unstable plots. Specifically, unstable plots will have more fine sediments and higher concentrations of sulfides, ammonium, organic matter content (OMC), and potassium permanganate oxidizable carbon (POXC), but lower amounts of nitrate, denitrifying enzymatic activity (DEA), and potential mineralizable nitrogen (PMN), as compared to stable plots. This study also hypothesized excess nitrate input to the wetland soils will increase DEA, alter PMN rates and decrease sulfide concentrations. Soil cores will be collected at 3 sites with triplicate stable and unstable marsh plots and one site with only stable plots, then transported to the lab for analyses. Preliminary data suggests nitrate concentrations and fine sediments differed by site, ammonium is lower in stable plots, and OMC and POXC are higher in stable plots. Results will provide biogeochemical indicators of marsh collapse, assisting the GTMNERR in the protection and restoration of their wetlands.
Jennifer Volk
Dr. Lisa Chambers, Advisor
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