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2006年6～7月对东海长江口及外海海域的调查数据显示,在所调查海域范围内32°N附近122°E～126°E之间存在NO2-N高值现象,NO2-N浓度最大值可达到2.38μmol/dm3,水深位于10 m以下。结合历史资料及不同季节调查数据分析:NO2-N高值现象春夏季存在,秋冬季消失。本文通过对NO2-N与温度、盐度、溶解氧、pH、表观耗氧量、颗粒有机碳及叶绿素之间的关系分析NO2-N高值现象的形成机制,结果表明:温度、盐度、密度跃层的存在是形成NO2-N高值现象的必要条件,亚硝化过程是NO2-N高值现象形成的主要原因。秋冬季节强风的搅拌作用使NO2-N垂直分布中跃层现象消失,从表到底NO2-N浓度相近,但秋季浓度水平仍较高;冬季则恢复到正常水平。
Data from June to July 2006 in the Changjiang Estuary and offshore waters of the East China Sea show that there is a NO2-N high value between 122 ° E and 126 ° E near 32 ° N in the surveyed sea area with the highest concentration of NO2-N The value can reach 2.38μmol / dm3, the water depth is below 10m. Combined with historical data and different seasons survey data analysis: NO2-N high values exist in spring and summer, autumn and winter disappear. In this paper, the formation mechanism of NO2-N high value was analyzed through the relationship between NO2-N and temperature, salinity, dissolved oxygen, pH, apparent oxygen demand, particulate organic carbon and chlorophyll. The results showed that the temperature, salinity The existence of density thermocline is a necessary condition for the formation of NO2-N high value. Nitrosation is the main reason for the formation of NO2-N high value. During the autumn and winter, strong wind agitation caused the phenomenon of thermocline NO2-N vertical distribution to disappear. Concentrations of NO2-N were similar in the table, but the concentrations in autumn were still high, while those in winter returned to normal levels.