Variations in aragonite saturation state and its controlling factors in the South Yellow Sea in spring and autumn.

To assess the progression of ocean acidification in the South Yellow Sea (SYS), the aragonite saturation state (Ω) was determined from dissolved inorganic carbon (DIC) and total alkalinity (TA) in the surface and bottom waters of the SYS in spring and autumn. The Ω exhibited large spatiotemporal variations in the SYS; DIC was a major factor controlling the Ω variations, whereas temperature, salinity, and TA were minor factors. Surface DIC concentrations were mainly influenced by the lateral transport of the DIC-enriched Yellow River waters and DIC-depleted East China Sea Surface Water; bottom DIC concentrations were affected by aerobic remineralization in spring and autumn.

Seasonal variation in aragonite saturation states and the controlling factors in the southeastern Yellow Sea.

The aragonite saturation state (Ω) was determined to assess its seasonal variations and the major controlling factors in the southeastern Yellow Sea (YS) over four seasons. Ω showed large seasonal variation in the surface waters, with dissolved inorganic carbon (DIC) as a major factor controlling the seasonal variation. In the bottom waters, Ω exhibited only small seasonal variation compared with the surface waters; DIC and total alkalinity were the main factors contributing to the variation.

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.