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. The bottom water of the southeastern YS was undersaturated with aragonite during the fall, even though the southeastern YS was not typically associated with upwelling, freshwater discharge, or eutrophication processes. Aragonite undersaturation was most likely due to ocean dumping of organic materials. Therefore, ocean pumping should be prohibited in shallow marginal seas to prevent aragonite undersaturation.