Aquatic Sciences Meeting, Albuquerque 2001

CS39 Trace Metal Limitation of Biogeochemistry

Date: Tuesday, February 13, 2001, Time: 2:30:00 PM

Location: Dona Ana

Baines, S, B, Marine Science Research Center, State University of New York, Stony Brook, USA, sbaines@ms.cc.sunysb.edu

Fisher, N, S, Marine Science Research Center, State University of New York, Stony Brook, USA, nfisher@notes.cc.sunysb.edu

INTERSPECIFIC VARIABILITY IN BIOACCUMULATION OF SE BY PHYTOPLANKTON AND ITS ECOLOGICAL IMPLICATIONS

Assimilation of dissolved Se by phytoplankton is the primary way that Se enters many aquatic food-webs. Using the radioisotope Se-75, we assessed phytoplankton uptake of selenite (Se(IV)), selenate (Se(VI)) and organic selenides (Se(-II)), determined the variability in Se bioconcentration among algal species, and measured the dependence of cellular Se contents on ambient concentrations of Se. Se(IV) and Se(-II) were more available than Se(VI) to phytoplankton, with uptake of Se(IV) and Se(-II) being strongly correlated (r2 = 0.9). Accumulation of Se differed among algal species by almost 4 orders of magnitude when exposed to 4.5 nM Se(IV) or Se(-II) and 5 orders of magnitude when exposed to 0.15 nM Se(IV). Uptake of Se(IV) was far less sensitive to ambient concentration. At Se(IV) concentrations typical of many estuaries, many species of phytoplankton can attain Se cell concentrations sufficient to cause toxicity to consumer organisms. Phytoplankton species composition may be a major determinant of Se toxicity in aquatic filter feeders and their predators.

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Aquatic Sciences Meeting, Albuquerque 2001

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