| The characteristics for distribution of cyanobacteria are closely with water blooming and the research on distribution characteristics of Yanghe reservoir cyanobacteria can provide scientific basis for revealing the cause of cyanobacteria bloom. In the study, field research and laboratory simulation are used to investigate the characteristics for spatial and seasonal distributions of Yanghe reservoir dominant algae, and the corresponding controlling factors are also analysised. The results are as follows. In the seasonal distribution, microcystis colonies occur in the late spring and have a greater biomass in the summer at the year, July and August-September, one each peak, the burst mode is a typical bimodal pattern. Anabaena filaments appear at late spring and reach the maximum biomass at the early fall. Lake simulator experiments showed that in the modelling diurnal vertical migration phase, when the water column is fully mixed, during light phase, Microcystis has a higher flotation rates than Anabaena, about 70% of Microcystis colonies and only 46% of filaments accumulated in the surface after 12 h light exposure. During dark phase, Anabaena have a higher flotation rates. About 66% of Anabaena filaments and 47% of Microcystis colonies accumulated in the surface after 12 h. The growth of Microcystis was significantly inhibited when the percentage of anaerobic leach liquor in M11 culture medium was high(≥20%), but there is obvious promotion of anaerobic leach liquor to the growth of Anabaena. Aerobic leach liquor had no influence on the growth of Microcystis, but the growth rate of Anabaena was promoted by aerobic leach liquor. The addition of Fe-citrat e·5H2O to the mixed culture medium (M11 culture medium +50% anaerobic leach liquor) significantly increased the maximum biomass of Microcystis, the results suggest that high organic matter concentration decreases iron availability for Microcystis. |
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