Climate-Driven Fluctuations in Anthropogenic CO2 Uptake by the East Sea in the North Pacific Ocean

Abstract

Ocean ventilation is a key mechanism for transporting anthropogenic CO2 (C-ANTH) from the ocean surface toward its interior. We investigated the link between ocean ventilation and C-ANTH increase in the East Sea using data from surveys conducted in 1992, 1999, 2007, and 2019. Between 1992 and 1999, the East Sea Intermediate Water (300-1,500 m) accumulated C-ANTH at a rate of 0.3 +/- 0.1 mol C m(-2) yr(-1). However, in the subsequent period (1999-2007) this rate decreased to <0.1 +/- 0.1 mol C m(-2) yr(-1). There was a resurgence in the C-ANTH increase rate between 2007 and 2019, reaching 0.4 +/- 0.1 mol C m(-2) yr(-1). The East Sea Intermediate Water ventilation changes, inferred from the changes in water column O-2 level and the Arctic Oscillation-driven winter surface temperature in the deep water formation region, were responsible for the periodic decline and recovery in C-ANTH increase.