Southeastern Yellow Sea as a sink for atmospheric carbon dioxide

Abstract

The seawater fugacity of carbon dioxide (CO₂; fCO_2SW) was investigated over four seasons in the southeastern Yellow Sea (YS). The seasonal variation in sea surface temperature (SST)-normalized fCO_2SW in the study area was largely explained by sea surface concentrations of dissolved inorganic carbon modulated by the water column stability in association with biological carbon fixation and remineralization. Overall, our study area acted as a sink for atmospheric CO₂, absorbing a regional average of ~2.8 mmol C m^-2 day^-1. This result contrasts sharply with the large CO₂ effluxes reported in other parts of the YS, implying considerable spatiotemporal variations in fCO_2SW in this region. Since the YS is significantly influenced by human activity, our data will serve as a baseline to record the human impact on ocean carbon cycles in the future.

Keywords: Air-sea CO(2) flux; Carbon cycle; East Asian marginal sea; Korean coastal water; Yellow Sea.