Carlson, P. R. Florida Marine Research Institute, carlson_pr@epic7.dep.state.fl.us
Yarbro, L. R. Florida Marine Research Institute, yarbro_l@epic7.dep.state.fl.us

 
RELEASE OF PHOSPHORUS FROM CARBONATE SEDIMENTS OF FLORIDA BAY, USA: THE POTENTIAL ROLE OF SEDIMENT SULFIDE.
 
To determine the potential role of sediment phosphorus in the initiation and maintenance of fall and winter phytoplankton blooms in Florida Bay, we have examined seasonal variations in sediment sulfide, iron and phosphorus. Sediment cores from 25 sites in the Bay were analyzed bimonthly from July 1996 through May 1997 for porewater sulfide and sediment porosity, and surficial core segments were subjected to a 3-step extraction procedure to separate inorganic and organic phosphorus and iron into porewater, sulfide-labile and acid-extractable pools. Porewater sulfide peaked in the fall across the Bay with maxima (1-8 mM ) in the northern and western Bay. Sediment iron (6-73 umol/g DW) was much higher than expected for carbonate sediments and was greater in the western Bay, suggesting advection from the Gulf of Mexico. Most sediment phosphorus (1-16 umol/g DW) was acid-extractable (mean = 60%) or residual organic (15-30%). Pools of porewater and sulfide-labile phosphorus were much smaller but peaked in the fall across the Bay. In general, highest labile phosphorus pools coincided with highest labile iron. Spatial and temporal patterns of labile phosphorus pools coincided with those of porewater sulfide concentrations suggesting a link between phosphorus and sulfur cycles in Florida Bay sediments.
 
Day: Thursday, Feb. 4
Time: Poster
Location: Sweeney Center
 
Code: SS30TH0506S