东海四个赤潮监控区水质状况比较的初步研究

Preliminary Study of Comparison on the Condition of Water Quality Among Four Red Tide-monitoring Areas of East China Sea

根据 2002 年度赤潮多发期东海岱山、象山港、三都湾和厦门 4 个赤潮监控区水质监测资料,分析、讨论了各赤潮监控区在赤潮多发期主要水质环境参数、营养盐结构、水质富营养化以及有机污染程度的异同,研究结果表明:在赤潮多发期,4 个监控区盐度和 pH, DO, COD 以及 DIP 含量差异不大,而NO2-N, NO3-N 和 NH4-N 含量差异最显著;营养盐结构分析则表明在赤潮多发期 4 个监控区 NO3-N 平均含量占 DIN 含量的 57.4 %～94.7 %,是监控区无机氮的主要存在形式,也是决定监控区 N 和 P 营养盐结构的主要环境因子,各监控区海域浮游植物的限制因子均为 P。富营养状态指数和水质指数分析则表明,除三都湾赤潮监控区外其他 3 个监控区水质均呈富营养化状态,且三都湾海域水质属轻度有机污染,而其他三个监控区海域水质均属严重污染。

In this paper, on the basis of the monitoring data of water quality in Daishan, Xiangshan Harbor, Sandu Bay and Xiamen red tide-monitoring areas of the East China Sea during the period of high frequency for the red tide in 2002, the similarities and differences in the major environmental parameters, nutrient structure, state of eutrophication and organic pollution among four red tide-monitoring areas are analyzed and discussed during the period of high frequency for the red tide. The results have shown that the differentia of salinity, DO, COD and DIP among four red tide-monitoring areas is small, but the differentia of NO2-N, NO3-N and NH4-N among them is significantly higher; According to the analysis of nutrient structure, NO3-N concentration is the dominant existing form of DIN in water quality, the ratio of NO3-N to DIN is 57.4 %～94.7 % among four red tide-monitoring areas of the East China Sea. NO3-N is a decisive environmental factor of N, P nutrient structure of monitoring areas, too. Moreover, P is a limiting factor of phytoplankton in the red tide-monitoring areas of the East China Sea. Based on the analysis of the index of eutrophication (E) and index of water quality (A), the water quality of the others is in the state of eutrophication except for the red tide-monitoring area of Sandu Bay, the organic pollution level of water quality in the red tide-monitoring area of Sandu Bay is low, and that in the others is serious.