Weak light promotes the algal succession from bloomed Microcystis towards diatom dominance under aeration disturbance
To study the effects of light shading and the biomass of cyanobacterial blooms on the algal community succession under continuous aeration disturbance,an experiment on Microcystis bloom control was conducted in a greenhouse.The experiment was an orthogonal test with four treatments(treatments Ⅰ,Ⅱ,Ⅲ,and Ⅳ)of both two gradients of algal biomass and light shading.The initial Microcystis bloom biomass was shown in chlorophyll a(Chla).Both treatmentsⅠandⅢwere in a low biomass of 384.32 μg·L-1 Chla,and treatmentsⅡ andⅣ were in a high biomass of 736.21 μg·L-1 Chla.TreatmentsⅠ andⅡ were under weak light with a shading rate of 99.4%,and treatments Ⅲ and Ⅳ were under comparatively strong light with a shading rate of 72.8%.During the experiment,the Chla concentration in each treatment gradually decreased,and the rank order from high to low was Ⅳ>Ⅲ>Ⅱ>Ⅰ(P<0.01),and they all succeeded from Microcystis dominance to other algae dominance.The diatom Nitzchia was the most dominant genus in both treatments Ⅰand Ⅱ with weak light conditions,in which the wet biomass accounted for 90.48%±9.29%and 93.64%±2.28%,respectively.In both treatments Ⅲ and Ⅳ,cyanophyta dominated,in treatment Ⅲ,Phormidium was the most dominant genus,followed by Microcystis and Nitzchia,and in treatmentⅣ,Microcystis was the most dominant genus,followed by Nitzchia and Phormidium.The results showed that the weak light caused by shading was an important factor affecting the algal succession from bloomed Microcystis towards diatom dominance.When using hydrodynamic disturbances to regulate cyanobacterial blooms,it is necessary to consider both the effects of light shading conditions and the biomass of the bloomed cyanobacteria.
Microcystis bloomalgal community structureaeration disturbanceshading ratediatom
万方数据
维普
