Bacterial diversity within different sections of summer seaice samples from the Prydz Bay，Antarctica

Abstract:

Abstract:［Objective］In order to assess bacterial abundance and diversity within three different sections of summer seaice samples collected from the Prydz Bay，Antarctica．［Methods］ Fluorescence in situ hybridization was applied to determine the proportions of Bacteria in sea-ice． Bacterial community composition within sea ice was analyzed by 16S rRNA gene clone library construction． Correlation analysis was performed between the physicochemical parameters and the bacterial diversity and abundance within sea ice．［Results］The result of fluorescence in situ hybridization shows that bacteria were abundant in the bottom section，and the concentration of total organic carbon，total organic nitrogen and phosphate may be the main factors for bacterial abundance．In bacterial 16S rRNA gene libraries of sea-ice，nearly complete 16S rRNA gene sequences were grouped into three distinct lineages of Bacteria (γ-Proteobacteria，α-Proteobacteria and Bacteroidetes)．Most clone sequences were related to cultured bacterial isolates from the marine environment，arctic and Antarctic sea-ice with high similarity． The member of Bacteroidetes was not detected in the bottom section of sea-ice．The bacterial communities within sea-ice were little heterogeneous at the genus-level between different sections，and the concentration of NH4+ may cause this distribution．［Conclusion］The number of bacteria was abundant in the bottom section of sea-ice． Gamma-proteobacteria was the dominant bacterial lineage in sea-ice．