9504251 SANSONE This team of investigators will study the biogeochemical processes associated with the decomposition of organic matter within (approximately) the upper framework of a coral reef just offshore of Oahu, Hawaii. Particulate and dissolved organic matter originating at or near the reef surface is hydraulically transported into this upper part of the reef where organic moieties are broken down in a suboxic or anoxic environment by heterotrophic bacteria. These studies should lead to a better understanding of nutrient cycling in coral reef ecosystems in many part of the world ocean. Also, because the suboxic reef environment is vertically extensive (about 1 meter deep), this system will afford the opportunity for detailed proxy study of suboxic decomposition processes that are common in other benthic environments, such as soft sediments, but which cannot be carried out in the latter because of the small spatial scale (typically several millimeters).