Planktonic bacterial community structure and its response to eutrophic factors in Lake ULanSuHai

Abstract:

[Objective] To investigate the planktonic bacterial community structure in Lake ULanSuHai and reveal its response to eutrophic factors. [Methods] DNA of total planktonic bacteria was extracted and used as template in the PCR amplification with bacterial universal primer pair 63F/1387R, and then PCR products were subjected to constructing 16S rRNA gene clone libraries of 3 different eutrophication level lake area, XK, HGB and SJB. Canonical correlation analysis (CCA) assay was applied to reveal the responses of bacterial community to eutrophication. [Results] The highest eutrophication level lake area-HGB has the highest diversity, richness and evenness, whereas XK of lowest eutrophication has the lowest diversity indexes. Proteobacteria, bacteroidetes and actinobacteria were dominant bacterial groups in Lake ULanSuHai. Abundances of α-, γ-, δ- proteobacteria, actinobacteria and bacteroidetes were varied greatly with the shifts of eutrophic levels. A lot of functional microbes with the probable ability degrading pollutants and cycling biogenic elements were detected in all sampled lake areas. Moreover, CCA analysis suggested that TN, NH4+, NO3? and COD had the most influence on planktonic bacterial community composition. Besides, there were plenty of unknown groups in Lake ULanSuHai. Some slightly alkaphilic and halotolerent bacteria were detected and they accounted for 9.6% of total bacteria in Lake ULanSuHai. [Conclusion] The diversity of planktonic bacteria is high in Lake ULanSuHai, and the community structure is complex and its composition is closely correlated with the eutrophic level of the lake waterbody.