Figure 1.

Conceptual diagram of the mutual interactions between trace metal nutrients (Fe, Mn, Zn, Co, Cu, Mo, and Cd) and phytoplankton in the sea. In these interactions the chemistry of trace metal nutrients (their concentrations, chemical speciation, and redox cycling) regulate the productivity, species composition, and trophic interactions of marine phytoplankton communities. These communities in turn regulate the chemistry and cycling of the trace metals through cellular uptake and assimilation, vertical transport of biogenic particles (intact cells and fecal pellets), mediation of metal regeneration processes (by grazers, bacteria, and viruses), production of organic chelators, and biological mediation of metal redox cycling.