THE EUTROPHICATION AND ITS REGIONAL HETEROGENEITY IN TYPICAL LAKES OF CHINA

In order to comprehensively evaluate the eutrophication status in China lakes, this study scientifically analyzed the eutrophication and its regional heterogeneity in 22 representative lakes of China, and the quantitative relationship between TP and eutrophication was also studied. The results showed that 59.1% of the surviving lakes are in different eutrophication status from 2010 to 2011. Among them, Yunnan-Guizhou Lake area has the highest eutrophication level, but Menggu-Xinjiang Lake area has a bipolar levels. The lakes at Northeast Mountain and Plain area, and also the lakes at eastern area generally have a level between middle nutrition to mild eutrophication. The lowest eutrophication level is at the area of Qinghai-Tibet Plateau. Based on the relationship between sunshine amount, frost-free period, temperature, water depth, altitude, precipitation and lake nutrition status, it reveals that the geographical location of lakes is the fundamental factor affecting lake eutrophication and its regional distribution. The results of comprehensive analysis showed that there is a significant correlation between chlorophyll a and total phosphorus concentrations in lakes nationwide. Cubic curve regression equation fits the relation between chlorophyll a and total phosphorus concentrations at the areas of eastern plain, northeastern plain-mountain, Qinghai-Tibet Plateau and Yun-Gui Plateau. S-curve equation fits the relation between concentrations of chlorophyll a and total phosphorus in the Menggu-Xinjiang Lake area. With the increase of total phosphorus concentration, there was a minimum value of chlorophyll concentration in the lake areas of eastern plain, northeastern plain-mountain, Qinghai-Tibet Plateau at the beginning, and then followed by a maximum value. The minimum concentrations of total phosphorus in the three lake areas were 0.054 mg/L, 0.089 mg/L and 0.072 mg/L, respectively. This study can provide information for the control of lake eutrophication in future.