1. Spatial Distribution of Different Forms of Sedimentary Phosphorus in Florida Bay: sequential extraction approach Jia-Zhong Zhang and Charles Fischer Ocean Chemistry Division, AOML, NOAA, Miami, FL 33149

2. Florida Bay

3. Bottom type

4. Low phosphate concentration in Florida Bay water Zhang & Chi, 2002

5. Sediment sampling station

6. Sequential extraction procedure

7. Percentage of CaCO 3 in Florida Bay sediments

8. Total Sedimentary Phosphorus in Florida Bay

9. Total exchangeable phosphorus by MgCl 2 extraction

10. Exchangeable Inorganic phosphorus by MgCl 2 extraction

11. Exchangeable organic phosphorus by MgCl 2 extraction

12. Iron-bound Phosphorus by dithionite extraction

13. Reactive iron in Florida Bay sediments

14. Salinity of Florida Bay water during sediment sampling By c ourtesy of Lee & John

15. CaCO 3 -bound total phosphorus by HAc (pH 4) extraction

16. CaCO 3 -bound inorganic phosphorus

17. CaCO 3 -bound organic phosphorus

18. Detrital phosphorus by HCl extraction

19. Residual refractory organic phosphorus by ashing

20. comparison

22. Percentage of Different Forms of Sedimentary Phosphorus

23. Summary Strong W-E spatial gradient in TSP and every forms of sedimentary P CaCO 3 -bound P accounts 44% of TSP Refractory organic P constitutes 24% of TSP Iron-bound P accounts 19% of TSP Exchangeable P accounts 8% of TSP

24. Sunset Acknowledgements: This research was supported by NOAA’s South Florida Ecosystem Restoration, Prediction and Modeling Program Recent Publications: Zhang, Jia-Zhong, Charles J. Fischer, and Peter B. Ortner, (2004) Potential availability of sedimentary phosphorus to sediment resuspension in Florida Bay, Global Biogeochemical Cycles. 18, GB4008, doi: 10.1029/2004GB002255, 2004. Zhang, J.-Z., J. Chi (2002) Automated analysis of nanomolar concentrations of phosphate in natural waters with liquid waveguide, Environmental Science & Technology, 36(5): 1048-1053.