Integrated Biogeochemical Studies of Contaminants in the Everglades: Task 1 -Nutrients, Sulfur, and Organic Matter

The scientific focus of this project is to examine the complex interactions (synergistic and antagonistic) of contaminants (externally derived nutrients, mercury, sulfur, pesticides, herbicides, polycyclic aromatic and aliphatic hydrocarbons, and other metals), ecosystem responses to variations in contaminant loading (time and space dimensions), and how imminent ecosystem restoration steps may affect existing contaminant pools. The major objectives of this project are to use an integrated biogeochemical approach to examine: (1) anthropogenic-induced changes in the water chemistry of the Everglades ecosystem, (2) biogeochemical processes within the ecosystem affecting water chemistry, and (3) the predicted impacts of restoration efforts on water chemistry. The project uses a combination of field investigations, experimental approaches (mesocosm experiments in the ecosystem, and controlled laboratory experiments), and modeling to achieve these objectives. Contaminants of concern will include nutrients, sulfur, mercury, organic compounds, and other metals. Protocols for the collection of samples and chemical analyses developed during earlier studies will be employed in these efforts. Integration of the individual tasks within the project is achieved by colocation of field sampling sites, and cooperative planning and execution of laboratory and mesocosm experiments. Results from all tasks within the project are archived within a single database for use in Decision Management GIS systems and ecosystem models.

This project is an integration of a number of individual but interrelated tasks that address environmental impacts in the south Florida ecosystem using geochemical approaches. The Everglades restoration program is prescribing ecosystem-wide changes to some of the physical, hydrological, and chemical components of this ecosystem. However, it reamins uncertain what overall effects will occur as these components react to the perturbations especially of the biological and chemical components and toward what type of "new ecosystem" the Everglades will evolve. Results of these geochemical investigations will provide the critical elements for building ecosystem models and screening-level risk assessment for contaminants in the ecosystem.