摘要：Temperature, salinity, chlorophyll a, and surface CO 2 fugacity ( f CO 2 ) were extensively investigated in the Ulleung Basin of the East/Japan Sea during four seasonal cruises. In spring, surface f CO 2 showed large variations ranging from 260 to 356 μatm, which were considerably lower than the atmospheric CO 2 levels. Surface f CO 2 was highest (316 to 409 µatm) in summer. The central part of the study area was undersaturated with respect to atmospheric CO 2 , while the coastal and easternmost regions were oversaturated. In autumn, the entire study area was fairly undersaturated with respect to atmospheric CO 2 . In winter, surface f CO 2 ranged from 303 to 371 µatm, similar to that in autumn, despite the much lower sea surface temperature. The seasonal variation in surface f CO 2 could not be explained solely by seasonal changes in sea surface temperature and salinity. The vertical mixing, lateral transport, and sea-air CO 2 exchange considerably influenced the seasonal variation in surface f CO 2 . The Ulleung Basin of the East/Japan Sea was a sink of atmospheric CO 2 in spring, autumn, and winter, but a weak source of CO 2 to the atmosphere in summer. The annual integrated sea-air CO 2 flux in the Ulleung Basin of the East/Japan Sea was -2.47 ± 1.26 mol m -2 yr -1 , quite similar to a previous estimate (-2.2 mol m -2 yr -1 ) in the south East/Japan Sea. This indicates that the Ulleung Basin of the East/Japan Sea acts as a strong sink of atmospheric CO 2 .
关键词：Seasonal variations; Surface fCO2; Sea air CO2 flux; Marginal sea; CO2 sink;
