SS4.03 Factors Controlling the Bioavailability and Bioaccumulation of Inorganic and Organic Chemicals into Aquatic Food Chains
Date: Friday, June 14, 2002
Time: 9:00:00 AM
Location: Carson B
 
StewartGM, Stony Brook University, Stony Brook, USA, gstewart@ic.sunysb.edu
Fisher, N, S, Stony Brook University, Stony Brook, USA, nfisher@notes.cc.sunysb.edu
 
UPTAKE AND TROPHIC TRANSFER OF POLONIUM IN MARINE PLANKTON
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Po-210 is a potential tracer of POC flux out of ocean surface waters but few studies have investigated the extent to which Po is concentrated by marine plankton and none have specifically assessed its biological cycling by quantifying its assimilation in marine animals. We measured the accumulation of Po in diverse algal taxa and found volume concentration factors (VCFs) ranging from 4.5 -35 e4, with no systematic differences among taxonomic groups. VCFs were unaffected by temperature or light but were significantly correlated with the surface area:volume ratios of the cells, suggesting that uptake is governed primarily by adsorption to cell surfaces. When copepods fed on labeled diatoms, the assimilation efficiency of Po in the animals was about 40%. Results will also be presented to relate assimilation with cellular distribution and protein content of the cellular components to which the Po was bound. These results, combined with field data for the behavior of Po in surface waters, indicate that Po can be used to trace sinking organic matter in a manner that may be more specific than Th or Pb.