黄河三角洲近岸海域营养盐分布与富营养化评价

摘 要：根据2010 年5月、8月和11月三个航次对黄河口主要入海河流附近海域9个调查站点海水化学资料，研究了该海域水体营养盐空间分布特征及其富营养化水平。结果发现：与历史数据相比，黄河口海域S上升，PO43--P污染加剧，DIN有所下降但含量仍超标；DIN 和COD沿黄河口向南递增，向北先递减，至刁口河、马新河海域又上升，主要与南部广利河、小清河，北部刁口河、马新河等入海河流径流量和污染程度较高相关。近岸海域富营养化超标率为55.6%，8 月的富营养化程度较高。有机污染指数（A值）8 月（3.07）>11月（2.05）>5月（1.40），分别为中污染、轻污染和开始受污染水平。对比两种评价结果可以看出，富营养化指数与有机污染指数具有较好的相互印证作用。COD 和DIN是造成黄河口附近海域富营养化的主要因子。8月、11月N：P比明显低于以往报道，叶绿素a与TN、DIN均呈极显著正相关（P<0.01），说明随着水体P含量逐渐上升，在春季以后黄河口海域水体正在由P限制型逐渐向N限制型转变。

Nutrients Distribution and Eutrophication Assessment on Coastal Waters Adjacent to Yellow River Delta

The nutrients distribution and the degree of eutrophication were studied based on the nutrient data from three cruises of oceanographic survey in May,August and November of 2010 in 9 stations adjacent to marine waters of the Yellow River delta.The results showed the salinity and inorganic phosphorus pollution increased,while inorganic nitrogen concentration decreased compared with historical data,still exceeding the standard;Along the Yellow River estuary southward,inorganic nitrogen concentration and COD concentration increased,and declined northward,then increased at the Diaokouhe River,the Maxinhe River area again,mainly correlating with the river runoff and pollution levels of the Guanglihe River,the Xiaoqinghe River in the south,and the Diaokouhe River,the Maxinhe River in the north.The eutrophication in coastal waters exceeded by 55.6%,and eutrophication was higher in August;Organic pollution index(A value)(3.07) in August>(2.05) in November>(1.40) in May,indicated intermediate pollution,light pollution and initial pollution stage respectively.COD and inorganic nitrogen concentration were the main factors of eutrophication.The ratio of N:P in August and November were significantly lower than was previously reported.Chlorophyll a and TN,inorganic nitrogen showed a highly significant positive correlation(P<0.01),indicating that with phosphorus in water increases gradually,the marine waters adjacent to the Yellow River Estuary is transiting from the P-dominated type to the N-dominated type after spring.