Aquatic Sciences Meeting, Albuquerque 2001

CS39 Trace Metal Limitation of Biogeochemistry

Date: Tuesday, February 13, 2001, Time: 3:45:00 PM

Location: Dona Ana

Dryden, C, L, Old Dominion University, Norfolk, USA, cdryden@odu.edu

Consolvo, J, A, Old Dominion University, Norfolk, USA, jconsolv@odu.edu

Gordon, A, S, Old Dominion University, Norfolk, USA, agordon@odu.edu

Donat, J, R, Old Dominion University, Norfolk, USA, jdonat@odu.edu

MICROBIAL RESPONSE TO ELEVATED COPPER CONCENTRATIONS IN A NAVAL HARBOR

In most natural waters, the speciation and bioavailability of copper are determined by its complexation with organic ligands. Several researchers have hypothesized a biological feedback mechanism involving metal-responsive ligand production by microorganisms (particularly picoplankton) in natural waters. We tested this hypothesis using in situ incubation of the natural resident microbiota in the Elizabeth River (Virginia), a major U. S. Naval harbor. In initial laboratory culture experiments we determined the copper levels and incubation times required to elicit microbial ligand production. The presence /absence of the copper addition, addition of a metabolic inhibitor, and a 0.2um filtered control were the experimental conditions used in our in situ studies. Results indicated that copper additions to cultures incubated in situ increased the concentration of copper-complexing ligands, with a corresponding decrease in the bioavailable free Cu2+ ion. When microbiota were removed or killed, a subsequent decrease in the copper-complexing ligand concentration and increase in free Cu2+ was observed. In situ incubation results appear to confirm the hypothesis that microorganisms are capable of buffering their environment against toxic levels of Cu2+ by producing copper-complexing ligands.

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Aquatic Sciences Meeting, Albuquerque 2001

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