Highly heterogeneous soil bacterial communities around Terra Nova Bay of Northern Victoria Land, Antarctica

Abstract

Given the diminished role of biotic interactions in soils of the continental Antarctica, abiotic factors have been believed to be the most prevailing parameter in structuring microbial communities. Many ice-free regions still remain unexplored and little is understood about which environmental gradients dominate the variation of bacterial communities. In this study, we investigated the soil bacterial community around Terra Nova Bay of Victoria Land using pyrosequencing and determined which environmental variables govern the bacterial community structure at the local scale. Six bacterial phyla such as Actinobacteria, Proteobacteria, Acidobacteria, Chloroflexi, Cyanobacteria, and Bacteroidetes were dominant but their relative abundance greatly varied across locations. Bacterial community structures were little affected by spatial distance but structured more strongly by site difference which parallels to the variation of soil physicochemical compositions. At both phylum- and species levels, bacterial community structure was explained most by pH and water content and to a lesser extent certain earth elements and trace metals also had important roles in shaping community variation. The higher level of heterogeneity of bacterial community structure found in this local site indicates how soil bacterial communities have been distinctively adapted to different compositions of edaphic variables under extreme environmental conditions. Taken together, these findings will greatly advance our understanding about how soil bacterial populations have been adapted to this harsh environment and how they will respond to changing climates in the future.