9414397 Levin This three-year award supports U.S.-United Kingdom cooperative research in biological oceanography on the role of oxygen as a forcing function for benthic processes in the Arabian Sea. The U.S. investigators are Lisa Levin, University of California at San Diego, Craig Smith, University of Hawaii, and the U.K. investigators are John Gage, Scottish Association for Marine Sciences, Tony Rice and others at the Institute of Oceanographic Sciences, and Paul Tyler of the University of South Hampton. The research will commence with field studies aboard the British ship RRS Discovery to be followed by analytic work in the U.S. and the United Kingdom. The U.S. investigators will examine changes in the macrofaunal community structure and associated shifts in bioturbation that occur in response to bottom-water oxygen gradients. Bioturbation will be evaluated using a naturally-occurring, particle- associated radiotracer, pigment tracers, seafloor photography and x-radiography. The British investigators will examine hydrography, benthic community metabolism and community structure of all faunal size categories. Resulting data will be used to test and improve existing models of benthic processes. The project takes advantage of British expertise and experience in different oceans. It also affords the U.S. investigators with an unparalleled opportunity to extend their previous studies of oxygen minimum zones and bioturbation to the Arabian Sea. This study on benthic processes and oxygen depletion in seafloors will advance knowledge and understanding of the effects of global warming on marine ecosystems. ***