Comprehensive Survey of Soil Bacterial Community Structure in Barton and Weaver Peninsula of King George Island, Antarctica

Abstract

Over the last few decades, terrestrial environments in Antarctica had been believed as sterilized habitats without any life forms because of the extreme environmental conditions. However, recent studies have started to report the unexpectedly high diversity of bacteria and their community structure is highly complex in these harsh environments. In this study, we investigated the bacterial community structure in soil samples collected from the Barton and Weaver Peninsula of King George Island. In total, 260 samples were taken from the upper (0-3 cm) and lower (3-10 cm) layer of soil during the period from December of 2010 to February of 2012. Bacterial community structure was analyzed by pyrosequencing targeting the V1-V3 region of 16S rRNA gene. Overall 409,863 sequence reads were obtained and 13,931 operational taxonomic units (OTUs) were generated when 97% similarity cutoff was used for OTU clustering. Actinobacteria (27.0%), Proteobacteria (19.3%), Acidobacteria (10.5%) and Chloroflexi (10.4%) were dominant across all habitats. Interestingly, candidate phylum AD3 (4.4%) was abundant in several soil samples, which has not been recognized in previous studies. Soil bacterial community structure was distinct to each habitat, paralleling to the spatial locality and physicochemical property of each habitat. Overall it appears that soil bacterial community is habitat-specific and varying chemistry of differing soil layers has a significant role in structuring bacterial communities in this environment.