The Quantitative Relationship Among Microcystis Aeruginosa, Bacterioplankton And Virioplankton In Eutrophication Water Bodies

By measuring the abundance of Microcystis aeruginosa,bacterioplankton, virioplankton and the concentration of total dissolved phosphorus and nitrogen in eutrophication water bodies,the quantitative relationship among M.aeruginosa,bacteria and viruses was studied in laboratory.The results indicated that the viral abundance had marked relation with the density of M.aeruginosa in the next day(r=-0.655,P＜0.01),its marked level was higher than the relativity in the same day(r=-0.578,P＜0.05).The number of bacteria closely correlated to the algae in the next day(r=-0.500,P＜0.05).The regression analysis suggested that the fluctuation of virus could explain 51.9%of the fluctuation of M.aeruginosa and the fluctuation of bacteria could explain 46.4%of the fluctuation of M.aeruginosa.The coefficient of determination of the regression equation of the M.aeruginosa and bacteria was lower than that of the M.aeruginosa and virus. Besides,the total dissolved phosphorus was negatively correlated to the number of algae(r=-0.747,P＜0.01) and positively correlated to the number of viral abundance (r=0.857,P＜0.01).The result implied that both virioplankton and bacterioplankton abundance may contribute to the control of M.aeruginosa density.It also demonstrated that virioplankton may accelerate the flow of phosphorus by lysing host cells in eutrophication water bodies.Based on the experiments in laboratory,an experiment in a small enclosure in Fubao Bay of Dianchi Lake was carried out.The results indicated that the chlorophyll a concentration had marked relation with the virioplankton abundance at the same time (r=0.376,p＜0.05),in the next 6 hours(r=0.428,p＜0.05) and in the next 12 hours (r=0.536,p＜0.05).Its coefficient of relation was increased gradually.The number of bacteria closely correlated to the virus in the same time(r=0.370,P＜0.05),but had no significant correlation with the virus of next 6 and 12 hours.The viral abundance had no marked relation with the chlorophyll a concentration.There was significant correlation between the abundance of bacterioplankton and chlorophyll a concentration in the next 6,12 and 24 hours(P＜0.01).The result implied that the increase of the virioplankton abundance was mainly decided by the biomass of M.aeruginosa..The virioplankton could not control the biomass of M.aeruginosa..The bacterioplankton inhibited the growth of M.aeruginosa..The use of FCM to detect virioplankton in eutrophied freshwater was studied.The results showed different processing method on sample has significant effects.TE was selected as buffer solution.The Samples should be fixed before detected.We chose SYBR Gold to dye the virus and the concentration should not be higher than 0.5×10^-4. The temperature for incubation should be at 80℃.Virus obtained by FCM were highly correlated to those obtained by EFM.The use of FCM could detect more virus.