9415790 SCRANTON This investigation will be a biogeochemical component of a times- series study of carbon cycling in the Cariaco Basin, a nature depression on the continental shelf of Venezuela. Because of restricted lateral water exchange with the open sea to the north, this Basin with its oxygenated surface waters overlying extensive anoxic waters offers an ideal opportunity to study organic decomposition near a oxidation-reduction boundary. In particular, this study will focus on the effects of carbon flux, sulfate- reducing and methanogenic bacteria, and grazing of the bacteria on the cycling of low molecular-weight fatty acids. The latter constitute an important class of fermentation intermediates and are key intermediates in carbon cycling under anoxic organic decomposition in the Cariaco Basin and should be extensible to other similar environments on the margins of the world ocean.
