CS08 Biogeochemical Cycles
Date: Monday, June 10, 2002
Time: 3:45:00 PM
Location: Saanich
 
ZhangJ, University of Miami, Miami, USA, Jia-Zhong.Zhang@noaa.gov
Fischer, C, J, AOML/NOAA, Miami, USA, Charles.Fischer@noaa.gov
 
SPATIAL DISTRIBUTION OF DIFFERENT FORMS OF SEDIMENTARY PHOSPHORUS IN FLORIDA BAY
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Total sedimentary P (TSP) in Florida Bay have been determined and were fractionated by a five-step sequential extraction procedure into five chemically-defined pools: (1) exchangeable inorganic and organic P, (2) Fe-bound P, (3) calcium carbonate-bound inorganic and organic P, (4) detrital apatite P, and (5) residual organic P. A strong gradient of decreasing TSP concentration was observed from the west (12 micromol/g) to the east (2 micromol/g) across the central Florida Bay. Among the five pools, the authigenic carbonate, fluorapatite and biogenic apatite as well CaCO3 associated phosphorus accounts the largest fraction of P (45% of TSP), of which inorganic P is dominant with organic P accounting for about 30% in sediments overlying productive waters and less than 10% in other areas of the Bay. The second largest pools are organic residue (24% of TSP) and Fe-bound P (19% of TSP). The exchangeable P accounts 8% of TSP, of which organic P accounts 60%. Detrital apatite phosphorus of igneous or metamorphic origin represents the smallest fraction (5% of TSP). On average, organic P accounts for 38% of TSP in Florida Bay sediments.