Aims:  The purpose of this study was to discuss how the environmental inputs and anthropogenic activities impact bacterial communities in the sediments of a shallow, eutrophic and temperate freshwater lake. Methods and Results:  Sediment cores were collected from Lake Dongping, located in Taian, Shandong, China. All samples were processed within 4 h of collection. Total nitrogen, total phosphorus (TP), total organic carbon, ammonium nitrogen and nitrate nitrogen content of samples were measured by Kjeldahl determination, sulphuric acid–perchloric acid digestion and molybdenum blue colorimetry, potassium dichromate titration, Nessler’s reagent colorimetric and the phenol disulphonic acid colorimetric method, respectively. Seasonal and temporal diversity of sediment bacterial communities at six stations in Lake Dongping were investigated using molecular approaches (terminal restriction fragment length polymorphism and 16S rDNA clone libraries). Noticeable seasonal and temporal variations were observed in bacterial diversity and composition at all six stations. Sediment bacterial communities in Lake Dongping belonged to 16 phyla: Proteobacteria (including α‐Proteobacteria, β‐Proteobacteria, δ‐Proteobacteria, ε‐Proteobacteria, γ‐Proteobacteria), Acidobacteria, Planctomycetes, Bacteroidetes, Firmicutes, Verrucomicrobia, Nitrospira, Chloroflexi, Gemmatimonadetes, Chlorobi, Cyanobacteria, Deferribacteres, Actinobacteria, OP8, Spirochaetes and OP11. Members of β‐, δ‐ and γ‐Proteobacterial sequences were predominant in 11 of 12 clone libraries derived from sediment samples. Sediment samples collected at stations 1 and 4 in July had the greatest bacterial diversity while those collected at station 2 in October had the least diversity. TP concentration was significantly correlated with the distribution of bacterial communities. Conclusions:  Our results suggested that different environmental nutrient inputs contribute to seasonal and temporal variations of chemical features and bacterial communities in sediments of Lake Dongping. TP concentration was significantly correlated with the distribution of bacterial communities. Significance and Impact of the Study:  This study has an important implication for the optimization of integrated ecosystem assessment of shallow temperate freshwater lake and provides interesting information for the subsequent of the ecosystem.

Bacterial communities in rhizosphere soil of healthy and diseased cotton (infected by the pathogenic fungus Verticillium dahliae Kleb.) were examined at different plant growth stages using T-RFLP and 16S rDNA clone library. At flowering and bolling, soil samples from the rhizosphere of healthy cotton had the highest richness, whereas the highest evenness was found in the rhizosphere of diseased cotton at boll opening. Acidobacteria and Proteobacteria were the main phyla in the cotton rhizosphere. Other phyla, including WS3, Deinococcus-Thermus, Verrucomicrobia, Firmicutes, Bacteroidetes, Actinobacteria, Thermomicrobia, Gemmatimonadetes, Planctomycetes, Proteobacteria, Cyanobacteria and unclassified bacteria were also found in cotton rhizosphere soils. Deinococcus-Thermus and Firmicutes were only present in diseased cotton rhizospheres. PCA analysis based on the 16S rDNA clone library demonstrated that six sampling resolved three groups of assemblages.