Emission of carbon dioxide from a tropical estuarine system, Goa, India

Abstract

Carbon dioxide species were studied in Mandovi-Zuari system, a tropical estuarine complex influenced by strong monsoonal run-off, with implications to build up and air-water exchange of CO sub(2) . Total carbon dioxide (TOC sub(2)) behaved conservatively during the estuarine mixing. Partial pressure of carbon dioxide (pCO sub(2)), evaluated from TCO sub(2) and pH couple, and carbonic acid dissociation constants, exhibited supersaturation with respect to atmospheric CO sub(2) round the year. The pCO sub(2) attained maximal levels over 2000 mew atm in waters of early estuarine mixing. Average pCO sub(2) in estuarine system were 1045 and 1153 mew atm (three times to that in atmosphere) in non- southwest (SW) and SW monsoon seasons, respectively. An experimental study revealed that soil-water interaction could be an important controller of pCO sub(2) abundance in these estuarine waters. The calculation water-to-air average fluxes were 67 and 11 m mol m sup(-2) d sup(-1), respectively,. In SW monsoon due to higher wind speeds and non-SW monsoons. This study strongly suggests the pH regulation by soil-water interaction is important, besides biological processes, in river and estuarine systems