Study On Test Method Of Lake Nutrient Bioassay

Nowadays, lakes and rivers are suffering a series of environmental problems, such as severe eutrophication, water quality deterioration and frequent algal-blooms, which caused by excess nutrients(nitrogen and phosphor)input from human activities. Once again, nutrient limitation becomes the hot issue that attracts many limnologist to discuss again. Between nitrogen and phosphor, which should be the main limiting factor to eutrophication control and phytoplankton biomass? How to determine nutrient limiting factors? How to determine the emissions of nutrients (nitrogen and phosphor) to avoid lake eutrophication? We need a scientific and effective method to find out the answer.(1) The N-P ratio hypothesis seems to be too simple and imprudent to analysis water as eutrophication criteria. Compare with it, integrated method which based on long-term historical data and biological experiment are more reasonable in assessing the algal response to nutrient changes and figure out the limiting factor.(2)Nutrient biological assessment method contains white-black bottle method, AGP, NEB. The article began to study on the difference among the three methods. NEB is considered a better way, because it reflects the response of original algal communities to nutrient concentration changes in specific natural water in the different time more actually and real. In addition, NEB is widely used in developed countries (European Korea). Though it was used in the research of marine limiting nutrient, no uniform processes about the method are settled.(3)Based on NEB test, further study about Nutrient biological assessment method is demonstrated in this paper. Through its theory research(principle、 significance、application), experiment methods are explored in laboratory(chemicals、 experiment、 method of nutrient add、 training cycle、 operation process). Molding method is used in the lakes of China. Analyze the feasibility of the molding method. Adjust the experimental methods. Based on the actual situation of China lakes, biological evaluation of nutrition, different methods of biological evaluation of nutrition are apply, addition of nutrients, mixture of surface water and bottom water, mixture of river water and lake water, mixture of storm runoff water and lake water.(4)Finally, a suit of testing code for Nutrient biological assessment was formed, which supplies a effective and reasonable method for determination of limiting nutrient factor in actually research, and a basal theory for eutrophication control and blooms reasonable.