9523910 Moffett Because the transport and reactivity of particulates in coastal waters may be strongly affected by protozoans during feeding and other manipulations, the cycling of chemical contaminants associated with such particles may also be significantly impacted. In this research, a team of scientists at the Woods Hole Oceanographic Institution will study the role of protozoans in the fate and transport of trace metal and organic contaminants in coastal waters. The suite of contaminants will include Cr, Pb,Cd,PAHs, and PCBs. The focus will be on estuarine and open coastal environments in which high concentrations of particle- associated contaminants coincide with rich water column and benthic microbial communities, because it is in such situations that protozoans would be most likely to affect particle transport and chemistry. Effects of protozoan grazing will be compared with bacterial and non-biological processes impacting the cycling of contaminants. Although the field work was originally planned for both Boston Harbor and New Bedford Harbor; it has subsequently been scaled back to involve only the latter. Laboratory studies will involve systems ranging from the very simple (one protist, one bacterial species) to the complex (natural marine microbial assemblages). The results should be extensible to contaminant cycling by protozoans in other marine environments.