| Abstract: | To elucidate the roles of microorganisms in the nitrogen geo-chemical cycle, the distributions of nitrogen-utilising bacteria were studied in a small eutrophic lake. Ammonifiers, nitrogen fixers and nitrate reducers were more concentrated at the severely polluted Xili sub-area than at the Centre of Outer (CO), whereas the contrary was true for autolithotrophic nitrifiers. Molecular identification of predominant ammonifiers and nitrogen fixers showed that two of the ammonifiers were γ-Proteobacteria, two were β-Proteobacteria, one was CFB group and the other three were low G+C% Gram positive Bacillus. Among four nitrogen fixers, one belonged to α-Proteobacteria, and the other three were γ-Proteobacteria. |
