[Influence of organic pollutants on the bacterial community in Songhua River drainage area].

In order to investigate the potential influence of the organic pollutants on the microbial composition and diversity, terminal restriction fragment length polymorphism (tRFLP) and 16S ribosomal DNA (rDNA) clone libraries combined with water quality analysis were selected to compare the structure of bacterial communities in four water bodies contaminated by different degrees of organic matter. tRFLP profiles of the waters and sediments all showed complex patterns and high similarity, however, some certain populations enriched with the pollution enhanced. Especially, the similarity of communities accorded strictly with that of water quality. Principal component analysis (PCA) indicated that the terminal restriction fragments (TRF) of bacteria in the waters and sediments grouped into different clusters. 16S ribosomal DNA sequences in the Songhua River sediment fell into ten known phyla and Proteobacteria are predominant with 21.92% of clones (in which the beta-Proteobacteria accounts for 10.96%). The sediment seriously polluted by domestic wastewater comprised of only 7 phyla, in which Proteobacteria was predominant with 47.37% of clones (subdivisions a-Proteobacteria and delta/epsilon-Proteobacteria were 21.05% and 15.79%, respectively). This study demonstrated that the long-term drainage of organic wastewater reduced the microbial diversity, and some functional microbes that are responsible for the degradation of organic matter, became dominant.