Carbon dioxide emissions from Indian monsoonal estuaries

Abstract

Estuaries are known to be strong source for atmospheric CO₂, however, little information is available from Indian estuaries. In order to quantify CO₂ emissions from the Indian estuaries, samples were collected at 27 estuaries all along the Indian coast during discharge (wet) period. The emissions of CO₂ to the atmosphere from Indian estuaries were 4–5 times higher during wet than dry period. The pCO₂ ranged between ∼300 and 18492 μatm which are within the range of world estuaries. The mean pCO2 and Particulate Organic Carbon (POC) showed positive relation with rate of discharge suggesting availability of high quantities of organic matter that led to enhanced microbial decomposition. The annual CO₂ fluxes from the Indian estuaries, together with dry period data available in the literature, amounts to 1.92 TgC which is >10 times less than that from the European estuaries. The low CO₂ fluxes from the Indian estuaries are attributed to low flushing rates and less human settlements along the banks of the Indian estuaries.