Study On Algae Growth Mechanism Of The Influence And Control By Endogenous Nutrients

At present,the exogenous pollutants in freshwater has been effect ively controlled,and the enogenous pollutants to be a key factor on the process of the eutrophication. Three main processes of lake eu trophication were described in this study:moderate eutrophication, s evere eutrophication, nutrient lakes the nutrient,at different pH,tempe rature,dissolved oxygen,researched the release of endogenous nitroge n,phosphorous,organic matter in the lake sediments,concluded the op timum environmental conditions of the release.And by simulating the best release environmental conditions,con cluded the different restriction of nutrients on algae growth,so as to provided theoretical support to control the lake eutrophication by u sing endogenous nutrients.(1),Collecting the lake sediments in three typical levels,studied the release law of their nutrient.The result showed that:in alkaline condition, TP,TN in the eutrophic lake sediment have the highest emission;In netural conditions,the organic matter has the maximum emission;Under anaerobic conditions,TP,TN,the organic matter in eutrophic lake sediment have the largest emission.Under the parallel experiment,the severe eutrophication has the largest emission of TP,TN and the organic matter.(2),Studing the different ratio of endogenous nutrients influent the algal growth mechanism in different eutrophic lakes,simulating the best emission condition of the nutrients in the eutrophic lake sediments,controlling the proption of nutrients in the overlying water,do some experiment,the result shows that:the large impact factor on the growth of algae is temperature.The degree of the endogenous nutrients influence on lake eutrophication are:severe eutrophication of lakes eutrophic lake> moderately eutrophication of lake>nutrient lakes.In the best emission condition of the lake sediments,as the temperature rose,TN,organic matter,TP as a factor limiting nutrients,the control effect is gradually increased.But the temperature is above 20℃, the control effect began to decrease,the optimal control section is 15-20℃;In the 15-20℃,moderate eutrophic lakes,TN,organic matter,TP as different restriction factor,its effect and the degree of control on the algae is different,TP's control effect is more than 82%,organic matter's control effect is approximately 76%,TN's control effect is only approximately 58%,In all,limits TP> organic matter>TN. Thus, different endogenous nutrients in controlling eutrophication have great significance.