中国部分河口及其近海水域缺氧现象研究

Progress in research of hypoxia in estuaries and coastal areas in China

对长江、珠江等河口及其近海水域缺氧现象与影响因素进行研究,结果表明,主要分布于长江与珠江河口及其邻近海域的缺氧现象,夏季(6—8月)达到最盛,秋冬季消失;长江口的缺氧区域主要位于30.75°N^32°N,122.5°E^123.25°E附近海域,具有南北2个缺氧中心;珠江口缺氧程度相对较轻,缺氧区域主要在广州黄埔区河段至虎门水域和伶仃洋;辽河、钱塘江、海河等河口区域也时而出现零星的缺氧现象;水体缺氧受控于多项环境要素,物理层化作用是缺氧产生的最初诱因之一,陆源污染物的分解则是重要的耗氧负荷;各河口区特征各异,潮汐、洋流、营养盐、叶绿素a等要素对缺氧区的范围、程度和持续时间影响程度不一。

In order to study hypoxia in the main estuaries and adjacent coastal areas in China, we compared the hypoxia in the estuaries of the Yangtze River, the Pearl River, and other rivers, and analyzed the factors.We found that hypoxia mainly occurred in the estuaries of the Yangtze River, the Pearl River, and the adjacent coastal areas;it had the most significant increase in the summer （from June to August） and disappeared in the autumn and winter.The hypoxia zone in the Yangtze River Estuary was mainly located in the area with latitudes from 30.75°N to 32°N and longitudes from 122.5°E to 123.25°E, and there were two hypoxia centers in the south and north, respectively.The degree of hypoxia in the Pearl River Estuary was relatively moderate, and hypoxia mainly occurred from the Huangpu section to Humen waters in Guangzhou and in the Lingdingyang Channel.In addition, hypoxia occasionally occurred in the estuaries of the Liaohe River, Qiantang River, and Haihe River.We also found that hypoxia was subjected to many environmental factors, of which the stratification of water was one of the initial factors and the decomposition of terrigenous pollutants was a major factor of oxygen consumption.Tides, upwellings, nutrients, and chlorophyll-a had different influences on the scale, degree, and duration of hypoxia, due to the various characteristics of the estuaries.