Microbial Community and Environmental Factors Affecting Copper Complexation in a Navy Harbor

Strong, dissolved, copper-complexing ligands are known to control copper speciation and bioavailability in most marine waters. We are testing the hypothesis that metal-responsive production of such ligands occurs in the Elizabeth River estuary, and that picoplankton and bacterioplankton produce the ligands. Recent studies utilizing cultures of marine picoplankton (Synechococcus) and bacterioplankton (Vibrio) have demonstrated that, when the cultures are exposed to elevated copper concentrations, these microbes produce copper-complexing ligands having copper-binding strengths similar to those found in marine waters. The primary objective of our study is to extend these observations to field conditions and natural assemblages of estuarine microorganisms in a naval harbor (the Elizabeth River, home of the US Atlantic Fleet). An additional objective is isolation and further characterization of the strong, copper-complexing ligands produced by microbes.