REGIONALLY VARIABLE CHEMISTRY, AUTO-HETEROTROPHIC COUPLING AND VERTICAL CARBON FLUX IN THE NORTHWESTERN INDIAN-OCEAN - A CASE-STUDY FOR BIOCHEMICAL PUMP

Large scale regional differences in surface productivity as well as wa ter column chemistry exist in the Arabian Sea environment in north-sou th direction. The available primary productivity data are incorporated into existing global ocean carbon flux models to estimate the potenti al vertical flux of carbon, and speculate on the nature of the autotro phic and heterotrophic processes, in the mixed layer and below, within the context of the observed regional chemical dichotomy. Based on the se considerations, hypothetical scenarios relating to regionally varia ble primary productivity, retention/loss of carbon in the water column , variable mineralization in the deep sea, etc, are formulated. Field testing of these hypotheses should provide a general framework for reg ional Arabian Sea oceanography in the coming years, especially with re spect to the Global Ocean Flux Studies.