Carbon fluxes in the China Seas: An overview and perspective

This paper aims to provide an overview of regional carbon fluxes and budgets in the marginal seas adjacent to China.The "China Seas" includes primarily the South China Sea, East China Sea, Yellow Sea, and the Bohai Sea. Emphasis is given to CO_2 fluxes across the air-sea interface and their controls. The net flux of CO_2 degassing from the China Seas is estimated to be9.5±53 Tg C yr^(-1). The total riverine carbon flux through estuaries to the China Seas is estimated as 59.6±6.4 Tg C yr^(-1). Chinese estuaries annually emit 0.74±0.02 Tg C as CO_2 to the atmosphere. Additionally, there is a very large net carbon influx from the Western Pacific to the China Seas, amounting to ～2.5 Pg C yr^(-1). As a first-order estimate, the total export flux of particulate organic carbon from the upper ocean of the China Seas is 240±80 Tg C yr^(-1). This review also attempts to examine current knowledge gaps to promote a better understanding of the carbon cycle in this important region.