Researches On Several Biological Character Of Microcystis During Water Bloom Dominant Species Forming

Eutrophication in lakes is a serious environmental problem existing all over the country. Appearance of water bloom together with eutrophication endangers drinking-water safety, aquiculture and lake environment. During water bloom Microcystis usually become dominant species, which draws enough attention from many people. According to the four-phase development hypothesis on the cyanobacteria bloom-forming, this paper pays attention to the biological character of Microcystis during recruitment, growth and float to the water surface together with colony forming, primary conclusions are as followed:(1) During recruitment period, cyanobacteria recruitment from sediments is important seed bank for their pelagic abundance. Cyanobacteria recruitment rose with some degree of fluctuation from March to June, peaking in April; in situ growth rate of cyanobacteria also showed a general increase over the same time, only reached maximum in early May. No apparent effect of zooplankton grazing was observed on the in situ cyanobacteria growth rates. Cyanobacteria recruitment only accounted for 2.0 % of the pelagic growth.(2) During growing period together with green algae, Microcystis aeruginosa dominance became more evident together with temperature...