Anthropogenic carbon is responsible for both global warming and ocean acidification. Efforts are underway to understand the role of ocean in a high CO2 world on a global context. However, marginal seas received little attention despite their significant contribution to biogeochemical cycles. Here we report that the CO2 increase and ocean acidification in the surface waters of the Ulleung Basin (UB) of the East/Japan Sea are much faster than the global mean, and possible causes are discussed. Twelve observations of surface fCO2 were made in the period from 1995 to 2004. The decadal trend of fCO2 increment was estimated by harmonic analysis. The estimated rates of increase of fCO2 were 1.97 μatm yr−1 for the atmosphere and 3.36 μatm yr−1 for the surface ocean. The rates exceed the global mean of 1.5 μatm yr−1. The ocean acidification trend, calculated from total alkalinity and fCO2, was estimated to be 0.04 pH units decade−1. Surface seawater of the UB has been acidified more rapidly compared to the global mean (0.02 pH units decade−1). Results show that, if warming strengthens the currents or advection in the marginal seas, biological pump will be enhanced. This would lead to compensation for the presumed reduction in oceanic uptake of atmospheric CO2 in the warmer world, which warrants quantification worldwide.
Kim J.-Y., Kang D.-J., Lee T. & Kim K.-R., 2013. Rapid increasing trend of CO2 and ocean acidification in the surface water of the Ulleung Basin, East/Japan Sea inferred from the observations from 1995 to 2004. Biogeosciences Discussions 10: 9573-9602. Article.