The Distribution Pattern Of Nutrient And Dynamic Analysis Of Eutrophication In Poyang Lake Region

Lake Pollution, induced by human activities with the development of society and economy, has been a serious environmental Problem, of which the eutrophication is one of the most important and harmful environmental Problem. Eutrophication is defined as the enrichment of surface waters with nutrient. Of these nutrients nitrogen(N) and Phosphorus(P) are important influence factors for Primary Productivity in aquatic ecosystems.In order to Prevent and control the eutrophication effectively, the sources and spatio-temporal distribution of the nitrogen and Phosphorus in lake should be under stood comprehensively.Poyang lake catchments situated at the south of Yangtze River midstream consist of five rivers(including Ganjiang River, Fuhe River, Xiushui River, Raohe River and Xinjiang River) and Poyang Lake. The water chemistry and spatio-temporal distribution of the nitrogen and phosphorus were studied in Poyang lake and the five rivers, and the sources of the N and P in the Poyang Lake were discussed primarily.According to the turn form the low water period to the average water period to the high water period, the concentration of the various of N and P is declined in Poyang Lake, It will be seen that the water volume is the main reason that affect the content of nitrogen and phosphorus.In terms of TN, the content of TN isn't change so much, but the TP reduce a lot, it is mainly because the temperature of water is high in summer, creature active tempestuously, and it is the outbreak period of Algae grows, aquatic life consume plenty of the dissolve phosphorus, it led to the content of phosphorus reduce by a large margin.The changes in space, the content of N and P in main lakes of Poyang Lake is relatively low. The export of Raohe River and Xinjiang River caused the concentration of individual points higher, the process of biodegradation and biodeposition is the main reason which cause the content of N and P reduce a lot. But the downstream is affected by the export of Ganjiang river,Xiushui River and Boyang river, the content of N and P in water body present the tendency of rising. The TN of Raohe is the highest in the main tributary of Lake, it is because the influence of industrial point sources and emission of sanitary waste.The content of TN and TP of Poyang Lake is obviously higher than the eccurred eutrophication of lake eutrophication. And the three essential elements which cause water body eutrophication is:enough nutritive salt, suitable hydrology weather condition, which Poyang Lake have had. As the lake has the question of eutrophication in varying degrees, moreover the local areas have possessed the basic conditions of hydrology, geography, weather and water quality ect and so on, which can led to seriously eutrophication. As long as the various conditions satisfied at one time, the happen of Water Bloom is inevitable.