Long-term changes in biogeochemical environments and their effects on dissolved oxygen concentrations in the East Sea

The East Sea (ES, or East/Japan Sea) is a semi-enclosed marginal sea where deep convection occurs and is therefore appropriate to identify the signals of climate changes. The substantial decrease in dissolved oxygen (DO) concentration has been observed in the deep layers of the ES compared to the globally averaged condition. In addition, in-situ and satellite-based measurement datasets as well as model results showed the enhancement of biological production in the upper layers. As such, changes in biogeochemical environments have been recorded in the ES due to the climate change, which also has a clear impact on long-term changes in the DO concentration.This study investigates the alternations of biogeochemical environments, from the surface to the deep layer of the ES, using a coupled physical-biogeochemical model. This modelling study also allowed a quantitative estimation of the biological effect on the DO concentration.