9311012 HANSELL Although most of the research effort in marine organic geochemistry has been directed toward particulate material, most of the organic matter in the world ocean is dissolved (DOM). Despite its abundance, little is known about the chemical nature of DOM, its reactivity and role in the marine carbon and nitrogen cycles, and its relationship to the global CO2 cycle. In this study the investigator will investigate the distribution, production, and mineralization of DOM (specifically the carbon and nitrogen components) in the Arabian Sea. As part of a team of scientists in the U.S. JGOFS Arabian Sea Process Study, the investigator will study the relationship of DOM production and mineralization to phytoplankton and bacterioplankton dynamics associated with seasonal forcing by the monsoon winds. By relating these studies to other scientists' simultaneous investigations of other aspects of carbon production, consumption, and transport, a clearer understanding of the role of DOM in the marine carbon cycle will be gained.