Patterns in the distribution of soil bacterial 16S rRNA gene sequences from different regions of Antarctica

Since the advent of 16S rRNA gene-based molecular analysis, an increasing amount of work has been conducted on the Antarctic soil bacterial community. The majority of such studies suggest that the Antarctic soil environment may harbour a greater diversity of bacteria than was previously thought, and indeed that a proportion of the bacterial species found might be unique to the Antarctic. However, few have looked at the distribution of soil sequence types from different biogeographic regions of the continent. Here, we assess the taxonomic distribution of soil bacteria from different regions and latitudes in Antarctica by integrating 16S rRNA gene sequence information from 13 independent studies that, together, obtained samples from 35 locations ranging from 51°S to 78°S. The majority of these formed a transect across the continent, representing most of the ice-free regions of the Antarctic Peninsula and Scott Sector. Using detailed phylogenetic analysis, we found that most of the Antarctic soil environments contained a narrow range of bacterial species when compared to the overall number of sequences available. Further, patterns in the taxonomic distribution of Antarctic soil bacterial communities were significantly correlated to both the underlying soil parameters and geographic (regional) origins.