Distributions and air-sea fluxes of CO2 in the summer Bering Sea

The 3rd Chinese National Arctic Research Expedition (CHINARE-Arctic Ⅲ) was carried out from July to September in 2008. The partial pressure of CO₂ (pCO₂) in the atmosphere and in surface seawater were determined in the Bering Sea during July 11-27, 2008, and a large number of seawater samples were taken for total alkalinity (TA) and total dissolved inorganic carbon (DIC) analysis. The distributions of CO₂ parameters in the Bering Sea and their controlling factors were discussed. The pCO₂ values in surface seawater presented a drastic variation from 148 to 563 μatm (1 μatm = 1.013 25×10-1 Pa ). The lowest pCO₂ values were observed near the Bering Sea shelf break while the highest pCO₂ existed at the western Bering Strait. The Bering Sea generally acts as a net sink for atmospheric CO₂ in summer. The air-sea CO₂ fluxes in the Bering Sea shelf, slope, and basin were estimated at-9.4,-16.3, and-5.1 mmol/(m2·d), respectively. The annual uptake of CO₂ was about 34 Tg C in the Bering Sea.