Variation Of Bacteria Community Stuctures In Eutrophic Water Body During Water Bloom

Eutrophication in the water environment, which would result in a series of problems, had become an environmental and scientific project. Biological treatment method has obvious advantage in contrast to physico-chemical methods because of no side effects and easy operation. And also microorganisms are responsible for the degradation and transformation of organic matter in water environment. Therefore, the researches about the bacterial community structure, function and diversity during the water bloom have great significances for the eutrophication remediation and enriching the limnology theory.This study choosed Yanghe Reservoir and Miyun reservoir as the experimental spots. Five surface water samples were collected continuously in the two Reservoirs, respectively. Different states of water bloom are measured by water quality and total amount of algae in water samples which were calculated by microscopy technique. The bacterial community structure of all the samples was studied by molecular biology techniques. And also the microbial community structure in the two reservoirs was compared.The total number of bacteria was examined respectively in different water samples by using microscopy technique and DAPI staining. The results showed that the total number of bacteria decreased in the early stage of water bloom, while there were no changes in the later period of water bloom. The eutrophication degree in Yanghe reservoir was higher than that of Miyun Reservoir.The bacterial community structure during different water bloom stages was studied by PCR-DGGE and 16S rDNA cloning technique. The results by PCR-DGGE indicated that the occurrence of water bloom had a significant impact on the Bacterial community structure. The content of Actinomycetes in Yanghe reservoir was stable during different stages of bloom, while in Miyun reservoir it was fluctuated between different stages of water bloom. Theα-proteobacteria existed in each stage of water bloom in the two reservoirs. Its abundance is higher in the later stage of water bloom in Yanghe reservoir. But in Miyun reservoir it was higher in the early stage. Furthermore, the results by 16S rDNA clone confirmed that the proportion of actinomycetes in different stages of water bloom in the two reservoirs was consistent with the result by PCR-DGGE. Theα-proteobacteria,β-proteobacteria,γ-proteobacteria, Verrucomicrobia, Fibrobacteres, Planctomycetes and Chloroflexi have different rules of succession in different reservoirs in the process of water bloom. But both species and quantity of Bacteroidetes were less in the outbreak period of algae than that in the rest period which showed different rule as other populations. The evenness of bacteria changed greatly in Yanghe reservoir, while little change was happened in Miyun Reservoir during the water bloom cycle.