Trace Metal Interactions with Marine Phytoplankton

AbstractLarge spatial and temporal differences in both trace metal concentrations and chemical speciation in the sea have led to wide variations in biological availability of metals and their effects on phytoplankton. Trace metals are usually taken up by algae via the formation of coordination complexes with specialized transport ligands in their outer membranes, and metal uptake is determined by the interplay between redox, complexation, or oxide dissolution reactions of metals in seawater and ligand-exchange reactions at these sites. Some metals, such as copper and zinc, are heavily chelated by organic ligands in seawater, and their biological availability is determined by the concentrations of free metal ions or of kinetically labile inorganic species (free ions plus inorganic complexes). Once inside cells, trace metals influence metabolism primarily as a consequence of the role of many of these metals (Fe, Mn, Zn, Cu, Co, Mo, Ni) as essential cofactors in metalloenzymes. Trace metals may also inhibit ...