Microbial Processes and Biogeochemistry of Wetlands

Research Team: Dr. Stephen P. Opsahl (Assistant Scientist) and Christopher Wheeler (Research Technician III)

Aquatic microorganisms are the major processors of organic and inorganic matter in wetland ecosystems and significantly alter water chemistry by remineralizing nutrients (N and P) and organic carbon or transferring these substrates into food webs. Thus, microorganisms provide a great ecological service by perpetuating natural cycles and mitigating environmental contamination. We are taking an interdisciplinary approach towards understanding the role of microbial processes within the context of the overall biogeochemistry of depressional and riparian wetlands. We use established and newly emerging techniques for evaluating microbial growth. Wetland microbial respiration and substrate limitation experiments We also use a broad array of chemical analyses to characterize microbial-induced changes in wetland chemistry. In our studies, we plan to include the dimension of surface water/groundwater exchange between depressional wetlands and the underlying Upper Floridan aquifer, and how the unique chemistry of the aquifer influences biological activity and nutrient cycles within the Chickasawhatchee Swamp. Specific topics that are currently being addressed include:

How does microbial metabolism in wetlands vary temporally, spatially, and at various stages of the hydrograph?
What substrates are limiting microbiological activity in wetlands?
How much organic carbon is relatively labile and bioavailable in the different wetland types?
How do wetlands affect water chemistry of the Upper Floridan aquifer?
Can surface waters and ground waters of the Chickasawhatchee Swamp be distinguished based on organic carbon composition?
Can the abundance of certain cations and anions be used to quantitatively evaluate groundwater/surface water interactions?

Coupled to hydrologic studies, these data will help better evaluate the roles of microorganisms in biogeochemical cycles within different types of wetlands and under different environmental regimes including flooding, drought, and nonpoint source runoff. In doing so, we hope to better describe how wetlands provide an important ecological service to society by improving water quality.

Research in progress, publications forthcoming.

Funded by: The Joseph W. Jones Ecological Research Center