Oxygen depletion off the Changjiang (Yangtze River) Estuary
Oxygen depletion off the Changjiang (Yangtze River) Estuary
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DOI：
10.1360/02yd9110
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发表时间：
2002-12
期刊：
影响因子：
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通讯作者：
Daoji Li;Jing Zhang;Daji Huang;Ying Wu;Jun-Ze Liang
中科院分区：
文献类型：
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作者：
Daoji Li;Jing Zhang;Daji Huang;Ying Wu;Jun-Ze Liang
1999年8月20-30日在黄、东海进行的调查中，发现长江口底部有一个平均厚度为20m、面积为13700km~2的缺氧带（<2mg/L），其最低含氧量为1mg/L。溶解氧亏缺的范围沿东海陆架底部向东南沿着向100 m等深线延伸。近20年来，长江口低氧区的最低溶解氧值由2.85mg/L下降到1mg/L。在低氧区，表观耗氧量（AOU）为5.8mg/L，耗氧量约为1.59 × 106t。长江、台湾暖流（TWC）的丰水作用，以及高浓度的颗粒有机碳（POC）和氮（PON），使缺氧带上方的盐跃层较强，是形成缺氧带的主要因素。POC：缺氧区的PON比值和营养盐浓度分布表明，夏季长江口东海底层水体缺氧是由于长江营养盐和河流有机质输入增加了有机碳的生成，进而导致东海营养盐再生发生变化的结果。
In a survey on the Yellow Sea and the East China Sea on August 20-30 of 1999, we found a hypoxic zone (<2 mg/L) of 13700 km2 with an average thickness of 20m at the bottom of the Changjiang (Yangtze River) Estuary, with an oxygen minimum value of 1 mg/L. The extension of the dissolved oxygen deficiency extended to the 100m isobath in a southeastward direction along the bottom of the continental shelf of the East China Sea. During the last two decades, the minimum dissolved oxygen values in the low oxygen region of the Changjiang Estuary have decreased from 2.85 mg/L to 1 mg/L. In the hypoxic zone, the apparent oxygen utilization (AOU) was 5.8 mg/L and the total oxygen depletion approximately 1.59 × 106t. The strong halocline above the hypoxic zone, as a result of affluent water from the Changjiang, Taiwan Warm Current (TWC), and the high concentrations of particle organic carbon (POC) and nitrogen (PON) are the major factors causing the formation of the hypoxic zone. The POC: PON ratios and nutrient concentration distributions in the hypoxic zone suggest that the oxygen deficiency in the bottom water during the summer in the East China Sea off the Changjiang is the result of organic carbon production enhanced by nutrients from the Changjiang and fluvial organic matter input, followed by a shift in regeneration of nutrients in the East China Sea.