Biogeosciences www.biogeosciences.net 1726-4170 1726-4189 3 4 2006 10.5194/bg-3-621-2006 http://www.biogeosciences.net/3/621/2006/ http://www.biogeosciences.net/3/621/2006/bg-3-621-2006.html http://www.biogeosciences.net/3/621/2006/bg-3-621-2006.pdf 621 633 2006-12-14 Coastal versus open-ocean denitrification in the Arabian Sea S. W. A. Naqvi naqvi@nio.org H. Naik A. Pratihary W. D'Souza P. V. Narvekar D. A. Jayakumar A. H. Devol T. Yoshinari T. Saino National Institute of Oceanography, Dona Paula, Goa 403 004, India School of Oceanography, University of Washington, Seattle, WA 98195, USA Wadsworth Center, New York State Department of Health, P.O. Box 509, Albany, New York 12201, USA Hydrospheric Atmospheric Research Center, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan now at: National Centre for Antarctic and Ocean Research, Headland Sada, Vasco da Gama, Goa 403 804, India now at: Department of Geosciences, Princeton University, Goyet Hall, Princeton, NJ 98544, USA The Arabian Sea contains one of the three major open-ocean denitrification zones in the world. In addition, pelagic denitrification also occurs over the inner and mid-shelf off the west coast of India. The major differences between the two environments are highlighted using the available data. The perennial open-ocean system occupies two orders of magnitude larger volume than the seasonal coastal system, however, the latter offers more extreme conditions (greater nitrate consumption leading to complete anoxia). 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