The Effects Of Disturbance On The Growth Of Microcystis Aeruginosa

With the increasingly serious problem of water eutrophication, recently years, great attention has been paying on it by governments and researchers all around the world. Microcystis aeruginosa,one of the most typical algae in euthrophic water body, was chosen as the research object. The effects of disturbance factor on the growth of this alga were thoroughly studied to provide theoretical basis of better control over the eutrophication problem of Qingcaosha reservoir. This study is supported by Science and technology innovation action plan of Shanghai , and it proposed aiming at the project one which named The integration and application of pre-control technology of Qingcaosha reservoir eutrophication .The effects of disturbance factor on the growth of Microcystis aeruginosa was studied on three aspects. Firstly, the disturbance effects on Microcystis aeruginosa growth under different nutrition concentrations were researched, and rich, middle and poor nutrition conditions, which score values more than 100, 80 and 60 respectively, were researched. Secondly, the exchange of upper and lower level of water body which caused by disturbance can effects the temperature and light, thus affecting the growth of alga. The disturbance effects on Microcystis aeruginosa growth under alternating changes in temperature and light were studied. Finally, for the disturbance can affect the air blend into water,and may be effect the utilization of Microcystis aeruginosa on carbon dioxide in the air, therefore, the disturbance effects on Microcystis aeruginosa Carbon dioxide concentrating mechanism (CCM) were investigated.The disturbance environment of this study was created by using blender and shaker to simulation water disturbance in laboratory, and the temperature and light conditions were controlled by an artificial climate trunk. The results showed that there exists a critical disturbance rate for the growth of Microcystis aeruginosa, and at the experimental condition of temperature 25?C, light intensity 4000 lx, the critical disturbance rate was 300r·min-1. The effect law of disturbance on the growth of Microcystis aeruginosa varies with the concentration of nutrition, and little effects was observed about the temperature and light variations on the growth of Microcystis aeruginosa. The utilization of Microcystis aeruginosa on the air showed a great dependence on disturbance, and this utilization significant impacted the growth of Microcystis aeruginosa by affecting the photosynthesis fluorescent parameters, biomass, nutrient absorption of Microcystis Aeruginosa and pH value of water body.In conclusion,this study proved that disturbance do affects the growth of Microcystis Aeruginosa, and one of potential reasons of the disturbance promoting the growth of Microcystis aeruginosa could be attributed to that the disturbance can provide sufficient carbon dioxide for the photosynthesis of Microcystis aeruginosa.