A comparison of CO2 dynamics and air-water fluxes in a river-dominated estuary and a mangrove-dominated marine estuary

TLDR: The fugacity of CO2 [fCO2 (water)] and air-water CO2 flux were compared between a river-dominated anthropogenically disturbed open estuary, the Hugli and a comparatively pristine mangrove dominated semi-closed marine estuary on the east coast of India as discussed by the authors.

Abstract: The fugacity of CO2 [fCO2 (water)] and air-water CO2 flux were compared between a river-dominated anthropogenically disturbed open estuary, the Hugli and a comparatively pristine mangrove dominated semi-closed marine estuary, the Matla on the east coast of India Annual mean salinity of the Hugli Estuary (≈ 71) was much less compared to the Matla Estuary (≈ 200) All the stations of the Hugli Estuary were highly supersaturated with CO2 (annual mean ~ 2200 µatm) whereas, the Matla was marginally oversaturated (annual mean ~ 530 µatm) During the post-monsoon season, the outer station of the Matla Estuary was under saturated with respect to CO2 and acted as a sink The annual mean CO2 emission from the Hugli Estuary (324 mol C m-2 yr-1) was 14 times higher than the Matla Estuary (23 mol C m-2 yr-1) CO2 efflux rate from the Hugli Estuary has increased drastically in the last decade, which is attributed to increased runoff from the river-dominated estuary