Biogeosciences

An Interactive Open Access Journal of the European Geosciences Union

| Contact |
Volumes and Issues  Contents of Issue 1  
Biogeosciences Discuss., 7, 25-53, 2010
www.biogeosciences-discuss.net/7/25/2010/
doi:10.5194/bgd-7-25-2010
© Author(s) 2010. This work is distributed
under the Creative Commons Attribution 3.0 License.

The Arabian Sea as a high-nutrient, low-chlorophyll region during the late Southwest Monsoon

S. W. A. Naqvi1, J. W. Moffett2, M. U. Gauns1, P. V. Narvekar1, A. K. Pratihary1, H. Naik1, D. M. Shenoy1, D. A. Jayakumar3, T. J. Goepfert4, P. K. Patra5, A. Al-Azri6, and S. I. Ahmed6
1National Institute of Oceanography (Council of Scientific & Industrial Research), Dona Paula, Goa 403 004, India
2Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
3Department of Geosciences, Princeton University, Princeton, NJ 08544, USA
4Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
5Frontier Research Center for Global Change, JAMSTEC, Yokohama 236 001, Japan
6Department of Marine Science and Fisheries, College of Agricultural and Marine Sciences, Sultan Qaboos University, Al-Khod 123, Sultanate of Oman

Abstract. Extensive observations during the late Southwest Monsoon of 2004 over the Indian and Omani shelves, and along an east-west transect reveal a mosaic of biogeochemical provinces including an unexpected high-nutrient, low-chlorophyll condition off the southern Omani coast. This feature, coupled with other characteristics of the system, suggest a close similarity between the Omani upwelling system and the Peruvian and California upwelling systems, where primary production (PP) is limited by iron. An intensification of upwelling, reported to have been caused by the decline in the winter/spring Eurasian snow cover since 1997, is not supported by in situ hydrographic and chlorophyll measurements as well as a reanalysis of ocean colour data extending to 2009. Iron limitation of PP may complicate simple relationship between upwelling and PP assumed by previous workers, and contribute to the anomalous offshore occurrence of the most severe oxygen (O2) depletion in the region. Over the Indian shelf, affected by very shallow O2-deficient zone, high PP is restricted to a thin, oxygenated surface layer probably due to unsuitability of the O2-depleted environment for the growth of oxygenic photosynthesizers.

Discussion Paper (PDF, 1765 KB)   Interactive Discussion (Closed, 4 Comments)   Final Revised Paper (BG)   

Citation: Naqvi, S. W. A., Moffett, J. W., Gauns, M. U., Narvekar, P. V., Pratihary, A. K., Naik, H., Shenoy, D. M., Jayakumar, D. A., Goepfert, T. J., Patra, P. K., Al-Azri, A., and Ahmed, S. I.: The Arabian Sea as a high-nutrient, low-chlorophyll region during the late Southwest Monsoon, Biogeosciences Discuss., 7, 25-53, doi:10.5194/bgd-7-25-2010, 2010.   Bibtex   EndNote   Reference Manager    XML
 

Search BG


News

Recent Papers