Air-sea CO₂ exchange process in the southern Yellow Sea in April of 2011, and June, July, October of 2012

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• 作者：Baoxiao Qu^a ; ^b ; Jinming Song^a ; ^{jmsong@qdio.ac.cn" class="auth_mail} ; ^{jmsong@ms.qdio.ac.cn" class="auth_mail} ; Huamao Yuan^a ; ^{yuanhuamao@qdio.ac.cn" class="auth_mail} ; Xuegang Li^a ; Ning Li^a
• 关键词：Carbon dioxide ; Air-sea exchange flux ; The southern Yellow Sea ; Vertical mixing ; The Changjiang plume
• 刊名：Continental Shelf Research
• 出版年：1 June, 2014
• 年：2014
• 卷：80
• 期：Complete
• 页码：8-19
• 全文大小：6006 K

文摘

The partial pressure of CO₂ (pCO₂) and air-sea CO₂ exchange flux (FCO₂) in the southern Yellow Sea (SYS, 120-125掳E, 31.5-37掳N) were investigated basing on the field surveys conducted in April of 2011, and June, July, October of 2012. With significant spatial variations, surface pCO₂ ranged from 243 to 574 渭atm, 206 to 620 渭atm, 102 to 655 渭atm and 328 to 557 渭atm in April, June, July and October, respectively. Nearshore area of Shandong Peninsula and Jiangsu Shallow (depth<50 m) were pCO₂-supersaturated (pCO₂=400-600 渭atm), as the result of intensive water mixing which brought the bottom CO₂-rich water to the surface layer. Conversely, offshore area of SYS center (depth>50 m) was pCO₂-undersaturated (pCO₂<390 渭atm) in April, June and October, but supersaturated in July. Phytoplankton production sustained by abundant nutrient and suitable hydrodynamic conditions was of great importance for this undersaturated pCO₂. Moreover, extreme low pCO₂ (pCO₂<300 渭atm) was observed in the Changjiang plume (32.5-33.5掳N, 123-125掳E) in July, which was also related with the biological uptake of CO₂. Average air-sea CO₂ exchange flux of the SYS in April, June, July and October was 鈭?.16卤0.40 mmol m^鈭? d^鈭?, 鈭?.56卤0.34 mmol m^鈭? d^鈭?, 鈭?.36卤0.51 mmol m^鈭? d^鈭?, and 6.67卤0.57 mmol m^鈭? d^鈭?, respectively. As a whole, the SYS behaved as a weak CO₂ sink during April to October, with an average flux for about 鈭?.35 mmol m^鈭? d^鈭?. As for the controlling factors for pCO₂ variation, temperature played the dominant role in October, whereas the non-temperature factors, such as vertical mixing, Changjiang plume and biological activity, were considered as the primary controlling factors in June and July. Spatially, the control of temperature on pCO₂ was predominant in the offshore SYS; the non-temperature factors were predominant in the shallow nearshore area, especially in coast of Shandong Peninsula and the Jiangsu Shallow.