On the seasonal variation of air-sea CO2 fluxes in the outer Changjiang (Yangtze River) Estuary, East China Sea
On the seasonal variation of air-sea CO2 fluxes in the outer Changjiang (Yangtze River) Estuary, East China Sea
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DOI：
10.1016/j.marchem.2009.02.008
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发表时间：
2009-12
期刊：
影响因子：
3
通讯作者：
W. Zhai;M. Dai
中科院分区：
文献类型：
--
作者：
W. Zhai;M. Dai
根据2005年4月至2008年4月在东海内陆架长江口外海域进行的7次现场调查，分析了表层CO2分压（pCO 2）和溶解氧（DO）的变化特征。该区域代表了东加勒比海最具活力的区域，高pCO 2的河水与高产的陆架沃茨交汇，面积为2°×3°，约占整个东加勒比海表面积的10%。冬季地表pCO 2范围为320 - 380 µatm（平均约345 µatm），春季为180 - 450 µatm（平均约330 µatm），夏季为150 - 620 µatm（平均约310 µatm），秋季为120 - 540 µatm（平均约375 µatm）。表层DO的季节变化与pCO 2的季节变化基本一致，冬季为95%~ 105%，春季为96%~ 142%，平均为110%，夏季为73%~ 192%，平均为118%，秋季为81%~ 178%，平均为102%.暖季（4 ~ 10月）pCO 2下降和DO增加的动力学过程主要受初级生产力和海气交换的控制，而冷季（11 ~次年3月）pCO 2下降和DO增加的动力学过程主要受混合作用的控制。研究表明，长江口外海域在冬、春、夏3个季节均为大气CO2的中度或显著汇，而在秋季则转为净源。长江口外海域的CO2通量为-1.9 ±1.3 mol m-2年-1，是近期估算的北方东海海域CO2通量的2倍。
Based upon seven field surveys conducted during April 2005 – April 2008, we examined the surface partial pressure of CO2(pCO2) and dissolved oxygen (DO) in the outer Changjiang (Yangtze River) Estuary, on the inner shelf of the East China Sea (ECS). This area represents a most dynamic zone of the ECS where high pCO2riverine water meets with highly productive shelf waters, covering a 2°×3° area, ~10% of the surface area of the entire ECS. Surface pCO2ranged 320 – 380 µatm (average ~345 µatm) in winter, 180 – 450 µatm (average ~330 µatm) in spring, 150 – 620 µatm (average ~310 µatm) in summer and 120 – 540 µatm (average ~375 µatm) in autumn. The seasonal variation pattern of surface DO generally mirrored that of pCO2, ranging 95% – 105% in winter, 96% – 142% (average 110%) in spring, 73% – 192% (average 118%) in summer and 81% – 178% (average 102%) in autumn. The dynamics of pCO2drawdown and DO enhancement in the warm seasons (from April to October) appeared to be controlled by primary productivity and air – sea exchange, while mixing dominated the aqueous pCO2in the cold seasons (from November to March of the following year). This study showed that the outer Changjiang Estuary served as a moderate or significant sink of atmospheric CO2in winter, spring and summer, while it turned to a net source in autumn. The integrated sea – air CO2flux in the outer Changjiang Estuary was estimated as −1.9±1.3 mol m−2year−1, which is double the recent sea–air CO2flux estimation for the northern ECS.