Diversity of nitrifying bacteria in microbial communities from water and epilithic biofilms of the Lake Baikal littoral zone

Abstract

Using the metagenomics approach and high throughput sequencing of the 16S rRNA gene amplicons, we studied the taxonomic diversity of nitrifying bacteria in microbial communities from epilithic biofilms and plankton of the littoral zone of Lake Baikal. The family Nitrosomonadaceae represents the diversity of ammonia-oxidizing bacteria; the genera (Nitrospirae) and Candidatus Nitrotoga (Gammaproteobacteria) nitrite-oxidizing bacteria; and the phyla Nitrospinae unidentified bacteria. Microbial communities from epilithic biofilms and the near-bottom water layer showed the highest diversity and those from the surface water layer the lowest one. Among ammonia oxidizers, bacteria of the uncultured genus Ellin6067 (27 phylotypes) dominated and were ubiquitous, and among nitrite oxidizers bacteria of the genus Nitrospira (7 phylotypes).