The first discovery of chemoautotrophic community living on a seafloor whale-fall carcass was made in the Santa Catalina Basin in 1987. Subsequent discoveries in the Pacific and the fossil record confirm that such communities are widespread in the modern ocean and have occurred over evolutionary timespans. The communities supported by the whale-fall environment bear taxonomic similarities to other deep-sea reducing environments, such as hydrothermal vents, and may occur with an average spacing of an order of magnitude smaller than that for vent fields. Whale-falls are of biogeographical significance for the following reasons: 1) they enhance the biodiversity of the deep-sea; 2) they can provide insights into the effect of anthropogenic influences, such as sewage sludge emplacement and persistent organic pollutants (POPs) on the marine environment; and 3) their potential roles as stepping stones for sulfophilic species in the deep-sea. The proposed work will continue to develop radiochemical methods (using thorium, radon and lead isotopes) for estimating the ages of seafloor whalebone communities. Preliminary measurements, using radiochemical methods, performed on known age bone samples yield isotopic ages that are in good agreement with known ages. The proposed work will undertake the following: 1) establishment of a final protocol for the dating techniques previously developed and make this product available to the scientific community; 2) initiate the study of lipid content and lipid characterization on dated bone material to assess the residence time of lipids within fallen whale skeletons; 3) attempt to assess a record of pollution, particularly persistent organic pollutants (PCB, DDT) within well-dated skeletal remains of whales; and 4) determine rates of development, patterns of succession, and persistence times of whale-fall chemoautotrophic communities.
