SEASONAL-VARIATIONS IN INORGANIC CARBON COMPONENTS IN THE CENTRAL ANDEASTERN ARABIAN SEA

Extensive observations have been made on the carbon dioxide system in the Arabian Sea during three different seasons as part of the Indian J oint Global Ocean Flux Study (JGOFS) Programme. Concentrations of tota l carbon dioxide and partial pressure of carbon dioxide exhibited seas onal variability, with pronounced north-south gradients in surface lay ers. Total carbon dioxide in surface waters was higher by similar to 1 00 mu M during winter compared to the intermonsoon period due to winte r cooling and convective mixing. The partial pressure of carbon dioxid e (pCO(2)) in surface layers was generally in excess over the atmosphe ric value, suggesting that the central and eastern Arabian Sea is a pe rennial source to atmospheric carbon dioxide, The flux of carbon dioxi de to atmosphere reached a maximum of similar to 40 mmole m(-2)d(-1) a round 16 degrees N in the central Arabian Sea during monsoon season, T he carbon dioxide regenerated from soft tissue was higher during winte r and is the least in monsoon. The aragonite saturation horizon occurr ed around 500 m.