9526610 Baker The proposed research program is a continuation of an interdisciplinary approach to chemical ecology. The objectives in a broad sense are the characterization and quantification of chemically mediated ecological relationships among antarctic benthic invertebrates. There are several specific objectives to investigate during two field seasons. Research will involve an evaluation of chemical defenses in adult antarctic marine invertebrates and also early life history stages. Investigators will evaluate lecithotrophic eggs, embryos and larvae for bioactivity. This is particularly relevant as many Antarctic invertebrates broadcast conspicuous lecithotrophic embryos and larvae which require two to six months to develop while in the plankton. It has been observed that colored sponges use their pigments as defensive agents, and their functional role will be investigated in sponges and in other colored invertebrates. Furthermore, bioactive metabolite concentration and sequestration will be investigated in invertebrates from which secondary metabolites have been isolated. And finally work will continue on the isolation and characterization of bioactive compounds from invertebrates for the purpose of evaluating their functional role. Significant aspects of the research are the use of ecologically relevant bioassays to guide the isolation, on-site at McMurdo Station, of the active chemical agents, and subsequent characterization of those metabolites at our home institutions. In summary, the proposed program will make a significant contribution to the understanding of the nature and role of bioactive agents in the ecology of the Antarctic marine benthos.
