Based On Nutrient Enrichment Bioassays Test Of Blooms Warning Research In Chaohu Lake

This study analyses of the history and data of the chaohu lake, and has a certain understanding the water quality of chaohu lake conditions. On the basis of the comprehensive nutrition state index method, combines the concrete conditions of chaohu lake, TLI index method was put forward, and applied to the chaohu lake eutrophication status evaluation, based on the algae blooms of algae growth biology evaluation test of early warning research provides the basis of theoretical support.Through the biological evaluation of algae growth test (NEB) field experiment, research different nutrient concentration added, along with the change of training days chlorophyll concentration and the change of the algal cell density, and then analyses the changes of phytoplankton and edge effects, different nitrogen and phosphorus nutrient addition on algae growth ratio and different time of impact.The main conclusions are as follows:(1) Monitoring data from2000to2008of the Chaohu Lake was analyzed in this study. Correlation coefficients between chlorophyll-a and total nitrogen, total phosphorus as well as transparency were obtained from the analysis. The differences between Chaohu Lake and other26lakes were then analyzed through the weights. An improved comprehensive nutrition state index method evaluation method was developed and evaluation approach was proposed. In the case of Chaohu Lake, the lakes nutritional status was evaluated, and the inter-annual and annual variation eutrophication levels were comprehensive evaluated. The results showed that the interrelation of each nutrient indicator has changed significantly in recent30years. The eutrophication problem in Chaohu Lake has become increasingly serious. The eutrophication level of Chaohu Lake has changed from mild eutrophic into a moderate eutrophic state.(2)Under the condition of different nitrogen and phosphorus ratio, the biggest standing crop chlorophyll a and algal cell density, relative coefficiency, total gaining rate has certain differences, and phytoplankton community composition, algal cell size differences, It is related to chlorophyll a content and single cell. The phytoplankton cell density and chlorophyll a, temperature and DO have a very good correlation, especially chlorophyll a, the correlation coefficient in this four months min0.786. (3) The chaohu lake phytoplankton community structure are mainly three kinds of cyanobacteria, green algae, diatoms, which mainly cyanophyta, phytoplankton community composition with training days change unceasingly, the species is also increasing, especially under the condition of high phosphorus concentration, edge effects and single microcystin algae, in the late culture become microcystin algae scenedesmus coexist, and visible microcystin algae is a major cause of blue-green algae outbreak.(4) In this test, the adding nitrogen phosphorus ratio range is between0.23to130.25. Studies have shown that when nitrogen and phosphorus close to10:1, the growth of algae is the best;Summer is a period of frequent occurrence of algae blooms, the special arrangement in May to August, the results showed that in July, the growth of algae reproducing is the strongest. It is visible that research of chaohu lake in China early water warning should beconcerned with the time, number of algal cells and other appropriate algae species, growth environment conditions, providing control of chaohu lake eutrophication phenomenon with certain measures.