Bacterial Community Shift in Depth Profiles of Permafrost Soil in Alaska

Abstract

Despite the potential contribution of thawing permafrost soil to the global climate change, the research of the microbial diversity has been scarce. In this study, we investigate the bacterial community in active layer soil from the Alaskan high Arctic based on 16S rRNA genes. These bacterial habitats contained relatively low number of OTUs ranged from 397 to 1728 compared to the temperate habitats. Although the bacterial diversity was relatively low, 20 known divisions and 27 unknown divisions were detected. The phyla of Proteobacteria (35.2%), Actinobacteria (20.9%) and Acidobacteria (16.5%) were predominant. Community shift was observed significantly along the soil depth profiles, which certain increase or decrease of relative abundance was detected in some phyla. The comparison between communities based on PCoA indicated that the bacterial composition was separated at 15 cm depth. This suggests that certain environmental parameters drive the formation of bacterial composition in this habitat. This study provides new insight regarding the bacterial communities in the Alaskan high Arctic permafrost.