Microbial uncultured community of bottom sediments from the bays of Gydan and Yenisei of the Kara Sea

Using methods of molecular biology (PCR and cloning), we studied the diversity of microorganisms in the surface layers of bottom sediments from the bays of Gydan and Yenisei of the Kara Sea, which have different component composition of the pore water and mineralization level. Representatives of the domains Bacteria and Archaea were identified based on the analysis of the 16S rRNA gene fragment nucleotide sequences. The composition of the community of microorganisms in the bottom sediments changed with the changing salinity gradient of the pore waters. The phylogenetic analysis of the nucleotide sequences showed that the composition of the microbial communities in the southern parts of these bays was affected by fresh-water flows from rivers and streams from the lakes within the catchment area, whereas that in the northern parts was influenced by sea waters. The results indicate the presence of bacteria in the bottom sediments that are capable of using a wide range of substrates as a carbon source including hydrocarbons and organochlorine and aromatic compounds. These data can also indicate the presence of different pollutants in the sediments of these areas and the potential ability of bacteria to degrade chemical compounds that enter the waters and bottom sediments of the Kara Sea.