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

Abstract

AbstractOcean ventilation is a key mechanism for transporting anthropogenic CO2 (CANTH) from the ocean surface toward its interior. We investigated the link between ocean ventilation and CANTH 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 CANTH 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 CANTH 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 O2 level and the Arctic Oscillation‐driven winter surface temperature in the deep water formation region, were responsible for the periodic decline and recovery in CANTH increase.