Correlation Analysis between Chlorophylla and Water Quality in Yin Lake in Summer and Its Eutrophication Evaluation

The correlation between chlorophyll-a and other environmental factors was analyzed,based on the continuous monitoring data in Yin Lake from May to July in 2009,and modified Carlson trophic state index was also used to assess the water quality of Yin Lake.The results showed that the chlorophyll-a had obvious temporal change characteristics.The content of chlorophyll-a in May was higher than that in July obviously,and that in the fishing region in area Ⅲ was the highest.Based on chlorophyll-a,transparence and total P and other parameters,according to modified Carlson trophic state index(TSIM53),an conclusion was drawn that the whole lake in summer was in eutrophic state.Significantly positive correlations were found between chlorophyll-a concentration and permanganate indexes,total nitrogen,but significantly negative correlation with transparency.At the same time positive correlation was found between chlorophyll-a and water temperature,pH,dissolved oxygen,total organic carbon.However,negative logarithmic correlation was found between chlorophyll-a and total phosphorus.