| Abstrakt: |
Ocean 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. Plain Language Summary: Ocean ventilation plays a crucial role in transporting anthropogenic CO2 from the surface toward the deep ocean interior. In the East Sea, demonstrating a direct causal relationship between ocean ventilation and anthropogenic CO2 uptake has remained elusive because of limited observational evidence. To address this knowledge gap, we conducted direct measurements of carbon parameters during four surveys in the East Sea that together spanned nearly three decades (1992, 1999, 2007, and 2019). Our investigation revealed a cyclical pattern of waxing and waning in the rate of anthropogenic CO2 increase within the East Sea over the past three decades. Significantly, we demonstrated that fluctuations in the ventilation of the East Sea were the primary driving force behind the decadal changes in anthropogenic CO2 increase. Furthermore, our research unveiled a potential connection between the periodic fluctuations in surface temperature linked to the Arctic Oscillation and variations in East Sea ventilation. Our findings shed light on the intricate dynamics between ocean ventilation, winter sea surface temperature patterns, and CO2 uptake in the East Sea. Key Points: The rate of anthropogenic CO2 increase in the East Sea showed cyclic trendsThe cyclic trends of anthropogenic CO2 increase were linked to the Arctic OscillationOur findings shed light on changes in anthropogenic CO2 uptake and transport by the global ocean in response to climate variations [ABSTRACT FROM AUTHOR] |
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