Monthly and seasonal variations in the surface carbonate system and air–sea CO2 flux of the Yellow Sea


  • CO2 chemistry was analyzed using the observation platform in the Yellow Sea.
  • Our study region acted as a sluggish sink for atmospheric CO2.
  • The amplitude of CO2 variations was comparable to reported values in the Yellow Sea.
  • Intra-seasonal variations of CO2 fluxes were observed in opposite directions.
  • Monthly observations are required for accurate estimation of air-sea CO2 flux.


Surface carbonate chemistry in the Yellow Sea was investigated based on discrete seawater samples collected from 2017 to 2020 at the Socheongcho Ocean Research Station (S-ORS; 37.423°N, 124.738°E). Records of carbon parameters, including seawater CO2 partial pressure (pCO2), revealed considerable seasonal variations, with amplitudes comparable to those observed across the western part of the Yellow Sea. The study site acted as a modest sink (−0.13 mol C m−2 yr−1) for atmospheric CO2. Biological processes (primary production and respiration) and physical conditions (temperature and degree of stratification) determined seawater pCO2, which fluctuated on an intraseasonal timescale between oversaturated and undersaturated with respect to atmospheric pCO2. Variation in pCO2 was significant in summer, depending on the biological carbon drawdown and tidal mixing-induced upwelling (increased pCO2 up to ~1000 μatm). The intraseasonal variability in seawater pCO2 may bias estimated air–sea CO2 fluxes, if measurements with a coarser (seasonal) time resolution are used.

Ko Y. H., Seok M.-W., Jeong J.-Y., Noh J.-H., Jeong J., Mo A. & Kim T.-W., 2022. Monthly and seasonal variations in the surface carbonate system and air–sea CO2 flux of the Yellow Sea. Marine Pollution Bulletin 181: 113822. doi: 10.1016/j.marpolbul.2022.113822. Article (subscription required).

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