The Synthetic Organic Program and the Biological Oceanography Program are co-supporting the research of Dr. William H. Fenical of the Scripps Institution of Oceanography at the University of California-San Diego. This interdisciplinary research program will explore the natural products chemistry of marine chemical defense. The program is based upon collaborative investigations of both the biological and chemical components of this significant, but poorly known, adaptation in marine habitats. Chemical studies of bioactive natural products, involving the use of new methods in separation science and organic structure determination, are combined with experimental ecological studies to illustrate the functions of secondary metabolites in competitive marine habitats. The overall goals of this program are to derive new classes of natural products from marine organisms, to comprehend the specific roles these compounds play in survival, and to understand how they influence community composition and structure in tropical marine environments.