Bacterial community structure of surface snow from victoria land in Antarctica

Abstract

In recent years, applications of molecular methods to study microbial ecology have allowed the extension of our knowledge that extreme environment contains unexpected high diversity of bacteria and their complex of community. Recently, a metagenomic study of snow suggested that snow bacteria can be adapted to photochemical reactions and oxidative stress in addition to cold stress, and therefore may form specific communities. In this study, we investigated the bacterial communities in Antarctic surface snow based on culture-dependent and ？independent approaches. Total 13 samples were collected from November in 2015 to January in 2016 around Victoria Land (East Antarctica). A total of 8 strains belonging to either Actinobacteria or Firmicutes were isolated from two samples. On the basis of 16S rRNA gene by pyrosequencing, overall 13,504 sequence reads were obtained, and 412 operational taxonomic units (OTUs) were generated with 97% similarity cutoff. Gammaproteobacteria (0.0~70.1%), Actinobacteria (1.9~67.8%), Firmicutes (0.0~45.8%), and Alphaproteobacteria (0.5~22.9%) were dominant. The dominant genera such as Propionibacterium, Aerococcus, and Micrococcus may have been deposited on the snow surface from the atmosphere. In contrast, genus Enhydrobacter may be considered most abundant as endogenous Antarctic snow inhabitants. These findings can get closer to the snow ecosystem, which occupy over a third of land surface area.