Changing of Microbial Community in a Large Eutrophicatied Shallow Lake

AbstractEight water samples were collected from Lake Taihu in different areas from a cyanobacteria bloom area to submerged grass abundant area in Feb of 2005. Culture-independent 16SrDNA-DGGE fingerprinting and FDC methods were used to reveal the community structure and abundance of the bacteria changed with the eutrophication. The results showed that bacterial community structure was affected to some extent by nutrient levels. The abundance of the bacteria increased with nutrient levels, in the center of lake Taihu, the bacteria abundance was only about a 106 cellseseses/ ml of × ses,1# of at the,2# sample sites, the bacteria abundance was increased to about a 106 cellseseses/ ml of × s; However, The number of DGGE bands in water decreased with increasing nutrient levels from the low to high nutrient level area, at the 1# sample site, the main bands were about 23; In the submerged grass abundant area of 7#,8# sites, there had the most main bands about 33. PCA analysis of the DGGE profiles showed that bacteria in the eight waters belonged to three groups. Bacterial community structure changed in different water samples. This study demonstrated that with the water eutrophication increased the bacteria biomass increased but the diversity of bacterial community decreased in the freshwater shallow lake