Interactive regulation of dissolved copper toxicity by an estuarine microbial community
Limnol. Oceanogr., 49(4), 2004, 1115-1122 | DOI: 10.4319/lo.2004.49.4.1115
ABSTRACT: Cultured marine microorganisms under copper stress produce extracellular compounds having a high affinity for copper (copper-complexing ligands). These ligands are similar in binding strength to those found in natural waters, but few studies have examined the relationship between copper, copper-complexing ligand concentrations, and natural microbial populations. A series of in situ experiments in the Elizabeth River, Virginia, revealed that an intact estuarine microbial community responded to copper stress by production of extracellular, high-affinity copper complexing ligands. The rate of ligand production was dependent on copper concentration and resulted in a reduction of the concentration of free cupric ions, Cu2+, by more than three orders of magnitude during a 2-week period in one experiment. We believe that this interactive response to copper stress represents a feedback system through which microbial communities can potentially buffer dissolved Cu2+ ion concentrations, thereby regulating copper bioavailability and toxicity.