Air-water CO2 evasion from U.S. East Coast estuaries

Other literature type English OPEN
Goossens, Nicolas ; Laruelle, Goulven Gildas ; Arndt, Sandra ; Cai, Wei - Jun ; Regnier, Pierre (2016)

This study presents the first regional-sca&ndash;45°&thinsp;N). The focus is on 43 tidal estuaries, which together drain a catchment of 697 10<sup>3</sup>&thinsp;km<sup>2</sup> or 76&thinsp;% of the total area within this latitudinal band. The approach is based on the Carbon &ndash; Generic Estuarine Model (C-GEM) that allows simulating hydrodynamics, transport and biogeochemistry for a wide range of estuarine systems using readily available geometric parameters and global databases of seasonal climatic, hydraulic, and riverine biogeochemical information. Together, US East coast estuaries emit 1.9&thinsp;TgC&thinsp;yr<sup>&minus;1</sup>, which correspond to about 40&thinsp;% of the carbon inputs from rivers, marshes and mangroves. Carbon removal within estuaries results from a combination of physical (outgassing of supersaturated riverine waters) and biogeochemical processes (net heterotrophy and nitrification). The CO<sub>2</sub> evasion and its underlying drivers show important variations across individual systems, but reveal a clear latitudinal pattern characterized by a decrease in the relative importance of physical over biogeochemical processes along a North-South gradient. Finally, results reveal that the ratio of estuarine surface area to the river discharge, S/Q (which has a scale of per meter discharged water per year), could be used as a predictor of the estuarine carbon processing in future regional and global scale assessments.
Share - Bookmark