This SGER (Small Grants for Exploratory Research) project pertains to chemical defense in zooplankton communities and its role in food web dynamics. It involves a collaboration between Dr. Jim McClintock (a Marine Invertebrate Chemical Ecologist), Dr. Bill Baker (a Natural Products Chemist) and Dr. Debbie Steinberg (a Biological Oceanographer). The specific research will focus on identifying chemicals responsible for deterrence in a defined subset of holoplankton. The project will examine aspects of chemical defense in 2 3 common oceanic holoplankton species that occur near Bermuda. It will employ ecologically relevant predators (fish and shrimp) in standard feeding bioassays to determine whether chemical extracts isolated from holoplanktonic organisms serve as feeding deterrents. This information will be critical to the development of a comprehensive understanding of the roles of bioactive compounds in the ecology of holoplanktonic communities.