Comparative analysis of bacterial community composition in Siberian permafrost and Antarctic pond sediments

Understanding the microbial diversity under very cold and usually frozen environments such as Siberia and Antarctica may lead to the discovery of traits important for life in extreme environments. We compared the bacterial community structure of Siberian permafrost and Arctic pond sediment by building 16S rRNA gene clone libraries, a culture-independent approach. Our goal was to explore the composition and to compare the diversity of these communities by utilizing an RDP high throughput pipeline tool and the following programs: DOTUR, EstimateS, Libshuff, MEGA and Classifier.; Four Siberia samples were selected according to the age which ranged from twelve thousand to three million years old, and from freshwater alluvial versus marine horizon. There were two samples from the Antarctic McMurdo Ice Shelf. They are pond surface sediments collected from Fresh pond and Brack pond on Bratina Island. These two ponds are next to each other but represent very different salinities in pond water. From the alpha diversity analysis, the Siberia samples showed lower diversities than Antarctica samples. Both Arctic and Antarctica sediments with the higher salinities showed lower diversity in bacterial community. The results from RDP Classifier showed that the Proteobacteria were the most dominant phylum in both regions.