projects > mercury transfer through an everglades aquatic food web > project summary
Project Summary Sheet
U.S. Geological Survey, Greater Everglades Science Program: Place-Based Studies
Fiscal Year 2002 Project Summary Sheet
Location (Subregions & Counties): Central Everglades; Miami-Dade
Funding (Source): Florida Dept. Environmental Protection funding to FIU; Base funding to USGS-BRD, Florida Caribbean Science Center
Supporting Organizations: Collecting permits - NPS and FFWCC. Mesocosm at ENP was used
Overview & Status: This study has been completed. The goal of this study was to identify the important routes and processes by which mercury is passed to the top trophic levels in the Everglades system. There were three study objectives. The first described the food habits and trophic positions of Everglades marsh fishes, and the changes in diet associated with seasonal water-level fluctuations. The dietary patterns for the Everglades community were compared with data for tropical wetlands from the literature. The data were used to construct a food web leading to the fishes. The second segment correlated total mercury concentrations in Everglades fishes and invertebrates to their trophic positions to test for bioaccumulation. The third segment examined the effects of time-of-year and site hydroperiod on mercury levels of wild and caged mosquitofish at three pairs of locations. This project is completed and manuscripts are in preparation for journal submission.
Needs & Products: 1) Loftus, W. F., J. C. Trexler, and R. D. Jones. 1998. Mercury Transfer Through an Everglades Aquatic Food Web. Final report to Florida Dept. of Environmental Protection, Tallahassee; 2) Loftus, W.F. 2000. Accumulation and fate of mercury in an Everglades aquatic food web. Ph.D. Dissertation, FIU, Miami, FL; 3) Arrington, D. A., K. O. Winemiller, W. F. Loftus, and S. Akin. In Press. How often do fishes "run on empty"? Ecology; 4) Several posters and presentations at meetings; other papers in preparation.
Application to Everglades Restoration: These data, combined with landscape-level studies of mercury geochemistry and patterns of concentrations in biota, will be useful as Performance Measures in RECOVER. The results were used in Phase 1 of the South Florida Mercury Program, in the development of the EPA BASS model of bioaccumulation, and in comparison with other studies in the Everglades.