春秋季长江口及其邻近海域营养盐污染研究

依据东海环境监测中心两个航次的资料和美国国家海洋大气管理局(NOAA)相关资料,开发Matlab计算机数值分析和图形显示技术,对长江口及其邻近海域的营养盐污染状况进行分析和探讨。结果表明:海域总体营养盐超标严重;氮、磷污染物的来源主要为径流携带入海,磷还受外海流系高质量浓度磷输入的影响;营养盐污染特征显示,表、底层营养盐均自入海口向外围、由近岸向远岸迅速递减,秋季冲淡水将污染物向外海携带,污染区也相应向外海推移;营养盐结构显示,该区w(N)/w(P)比值最高达到了405,无机氮异常丰富,海域浮游植物生长的限制因子存在时空变化。分析得到营养盐污染特征与长江河口锋位置及冲淡水流向的关系密切,可以考虑由长江河口锋位置及冲淡水流向来确定污染物的聚集位置和扩展方向。

Nutrient pollution round Yangtze Estuary in Spring and Autumn

The nutrient data, measured round Yangtze estuary in 1998 and from NOAA, are analyzed using the Matlab computer programming, to study the nutrient pollution round Yangtze Estuary and its adjacent sea area. It can be shown from the results: around Yangtze estuary, the nutrient contamination was very seriously; the nutrients with nitrogen and phosphorus were mostly come from the river discharges, and phosphorus concentration was also influenced by outer sea currents which contain high phosphorus. The nutrient pollution distributions showed that the nutrient concentration at surface and bottom of shore was decreasing from coast to off shore. With fresh water current extending in autumn, the area of contamination was increasing offshore. For the structure of nutrients, the highest value of w(N)/w(P) ratio came to 405 and the DIN was abundance; but the nitrogen or phosphorus limitation, which limited the growth of phytoplankton, had the space-time changes. It was proved that the distribution of nutrients pollution connected with the position of Yangtze estuarine front and the direction of fresh water current out shore. The position and spreading direction of contamination, can be indicated by the position of the estuarine front and the direction of fresh water current.