CO2 uptake and ocean acidification in the East/Japan Sea

Abstract

Anthropogenic CO2 concentrations were determined in the East Sea using high quality carbon dataset collected in 1999. Anthropogenic CO2 has already reached to the bottom of the East Sea. The highest specific column inventories were found in the Japan basin where deep water formation occurs. The anthropogenic CO2 inventory of the East Sea was much higher than that for the Pacific Ocean, but similar to the value for the North Atlantic. As a result, saturation horizons for aragonite and calcite have lifted by 80-220m and 500-700m, respectively, which was approximately 5 times greater than those found in the North Pacific.One of vulnerable habitat to ocean acidification (OA) is coastal region which is frequently exposed to wind-driven upwelling. Thus we investigated temporal changes in seawater carbonate system and the effect of upwelling on OA in Hupo, a central part of the east coast of Korea. Estimated net sea-air CO2 flux was &#8722 1.99 ± 1.18 mol C m&#8722 2 yr&#8722 1, indicating that this region was a sink for atmospheric CO2. Our monthly data revealed temporal changes in surface CO2 concentrations and CaCO3 saturation state (Ω) were mainly governed by physical and biological processes. In particular, wind-driven upwelling observed in July 2013 brought waters with high nutrients/CO2, and low pH/Ω to the surface and thus enhanced biological production in surface waters. OA in this coastal ecosystem is expecte the Japan basin where deep water formation occurs. The anthropogenic CO2 inventory of the East Sea was much higher than that for the Pacific Ocean, but similar to the value for the North Atlantic. As a result, saturation horizons for aragonite and calcite have lifted by 80-220m and 500-700m, respectively, which was approximately 5 times greater than those found in the North Pacific.One of vulnerable habitat to ocean acidification (OA) is coastal region which is frequently exposed to wind-driven upwelling. Thus we investigated temporal changes in seawater carbonate system and the effect of upwelling on OA in Hupo, a central part of the east coast of Korea. Estimated net sea-air CO2 flux was &#8722 1.99 ± 1.18 mol C m&#8722 2 yr&#8722 1, indicating that this region was a sink for atmospheric CO2. Our monthly data revealed temporal changes in surface CO2 concentrations and CaCO3 saturation state (Ω) were mainly governed by physical and biological processes. In particular, wind-driven upwelling observed in July 2013 brought waters with high nutrients/CO2, and low pH/Ω to the surface and thus enhanced biological production in surface waters. OA in this coastal ecosystem is expecte