Southeastern Yellow Sea as a sink for atmospheric carbon dioxide.

The seawater fugacity of carbon dioxide (CO; fCO) was investigated over four seasons in the southeastern Yellow Sea (YS). The seasonal variation in sea surface temperature (SST)-normalized fCO 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 CO, absorbing a regional average of ~2.8 mmol C m day. This result contrasts sharply with the large CO effluxes reported in other parts of the YS, implying considerable spatiotemporal variations in fCO 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.