The central and Arabian Sea as a perennial source of atmospheric carbon dioxide

By V. V. S. S. SARMA, M. DILEEP KUMAR* and M. D. GEORGE

National Institute of Oceanography, Dona Paula Goa 403 004, India.

Seasonal (winter monsoon, intermonsoon and southwest monsoon) and interannual (between southwest monsoon season of 1995 and 1996). Variations in total carbon dioxide (TCO2) and partial pressure of CO₂(pCO₂) were studied in the central and eastern Arabian Sea as a part of the JGOFS (India) Programme. The pCO₂ values were computed from the results of coulometric TCO₂ and spectrophotometric pH measurements. Seasonal variability in TCO₂ is evident with the changing circulation and biological production. In all season the pCO₂ is higher on surface water of the Arabian Sea except along the Indian Coast in the southwest monsoon than that in atmosphere and thus this region appears to be a perennial source of atmospheric CO₂. Significantly an average of ~45Tg y ^-1 could be eject to atmosphere from the study region that seems to far exceed the earlier estimations. The estimated fluxes, however are in agreements with those from the eastern equatorial Pacific Ocean.