Comparison of the Eutrophication Extent in Yangtze River Estuary and Its Adjacent Waters in 2004 and 2005

Based on the four months' investigations in 2005,and used the artificial neural network to assess eutrophication of the Yangtze River Estuary and its adjacent waters,this study aimed to integrate the research results in 2004,and compare the extent of eutrophication in the two years.The results showed that over 70% sample stations in May and August of both two years were mesotrophy and eutrophication;and over 40% sample stations in February and November were mesotrophy and oligotrophy in both years.It was more serious in 2005 than 2004,not only the sample stations of eutrophication,but also the extension of it;the eutrophication extent in 2004 from February to November were May,August,November and February;and in 2005 were May,August,February and November.The high incidence season of eutrophication was May in spring.