1. Evaluating the Influence that Anthropogenic Inputs have on Carbon and Nitrogen Cycling and on the Biological Assemblages in Tampa Bay, FL David Hollander, Elon Malkin, Ed Van Vleet College of Marine Science, St. Petersburg, FL 33701 in collaboration with T. Edgar, T Cronin, P. Swarzenski, K. Yates, USGS Program Leaders Project Objectives: Determine how historical human influences have: Altered the geochemical cycling of carbon and nitrogen (today’s presentation) Modified ecosystem structure as recorded in the inputs of sedimentary organic matter.

2. Research Strategy Field studies: Sediment coring throughout Tampa Bay Analytical approach: Organic carbon and nitrogen concentrations –reflects increasing input & production of organic matter –C:N Ratios determine algal vs terrestrial inputs Stable Isotopes of organic carbon and nitrogen –reflects specific nutrient inputs and assimilation –trophic relationships Molecular organic geochemical analysis –reflects organic inputs (algal, bacterial, terrestrial and pollution) Historical Land-use characterization: USGS mapping group Southwest Water management District

3. Linking the Sedimentary Geochemical Record in Tampa Bay to Historical Changes in Land Use Development and Nutrient Inputs Watershed’s land use Urban / Industrial, Agricultural, Natural Recorded in Tampa Bay’s Sediments: TOC, TON, C/N,  15 N, Molecular Biomarkers Changing nutrient inputs: Sources- 15 N specific concentrations bioavailability

4. Safety Harbor/ Feather Sound Hillsborough Bay/ Alafia River Terra Ceia/ Aquatic Preseerve Study Sites: Sediment Cores Geochemical Studies Area of land-use characterization Tampa Bay 6 Watersheds Variable land-use

5. Historical Land-Use Changes Alafia: increasing urbanization/industrialization Terra Ceia: increasing agriculture, recent urban Feather Sound: increasing residential urbanization

6.  15 N, o/oo Air Fertilizer Land Plants Soil Urban-Sewage Industrial Specific Nutrient Input Nitrogen Isotope Fingerprinting of Nutrient Inputs Safety Harbor- Residential Terra Ceia- Agriculture Hillsborough- Urban

7. Linking Sedimentary & Land-Use Records: TON/TOC- 4x increase due to nutrient input and increased production Transition from vascular plant to algal/bacterial inputs (C:N, biomarkers) Enriched 15 N > 10 ‰, coprastanol reflect wastewater-industrial inputs 19521995 TOC, Wt% C/N, Atomic Ratio  15 N, ‰ Air Depth (cm) AlgalTerr PlantsSoilUrban TON, Wt% Fertilizer/ Ter Plant Redeposited layer Hillsborough Bay/Alafia River Urbanization/Industrialization Human Impact

8. Linking Sedimentary and Land-Use Records 1952 Increasing nutrient inputs leading to production (TOC/TON) Transition from vascular plant to algal/bacterial inputs (C:N, biomarkers) 15N- Agricultural nutrient mimic vascular plant inputs, recent urban 1995 Depth (cm) Agricult/ TerPlant TOC, Wt%C/N, Atomic Ratio  15 N, ‰ Air TON, Wt% Terra Ceia/Aquatic Preserve Agricultural Recent urbanization Soil Urban Fertilizer/ Terr Plants Algal Terr Plants Human Impact Alafia

10. Geochemical Implications for Ecosystem Modes Enables “hind-forecasting” of regional Bay productivity Linking biological responses recorded in sediments to historical land use and nutrient inputs Allows model refinement of nutrient forcing functions Distinguishing nutrient abundance from bioavailability Allows for predictive food-web behavior Defines relationships among nutrient inputs, primary productivity, and the abundance of economically important upper trophic level consumers