Autumn CO₂ chemistry in the Japan Sea and the impact of discharges from the Changjiang River

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• 作者：Naohiro Kosugi ; Daisuke Sasano ; Masao Ishii ; Kazutaka Enyo ; Shu Saito
• 刊名：Journal of Geophysical Research: Oceans
• 出版年：2016
• 出版时间：August 2016
• 年：2016
• 卷：121
• 期：8
• 页码：6536-6549
• 全文大小：2.0MB
• ISSN：2169-9291

文摘

We made comprehensive surface water CO₂ chemistry observations in the Japan Sea during each autumn from 2010 to 2014. The partial pressure of CO₂ (pCO₂) in surface water, 312–329 μatm, was 10–30 μatm lower in the Japan Sea than in the same latitude range of the western North Pacific adjacent to Japan. According to the sensitivity analysis of pCO₂, the lower pCO₂ in the Japan Sea was primarily attributable to a large seasonal decrease of pCO₂ associated with strong cooling in autumn, particularly in the northern Japan Sea. In contrast, the lower pCO₂ in relatively warm, freshwater in the southern Japan Sea was attributable to not only the thermodynamic effect of the temperature changes but also high total alkalinity. This alkalinity had its origin in Changjiang River and was transported by Changjiang diluted water (CDW) which seasonally runs into the Japan Sea from the East China Sea. The input of total alkalinity through CDW also elevated the saturation state of calcium carbonate minerals and mitigated the effects of anthropogenic ocean acidification, at least during autumn. These biogeochemical impacts of CDW in the Japan Sea last until November, although the inflow from the East China Sea to the Japan Sea almost ceases by the end of September. The long duration of the high saturation state of calcium carbonate benefits calcareous marine organisms.