Microbial Communities in a High Arctic Polar Desert Landscape

Clare M Mccann,Casey R J Hubert,Neil D Gray,David W Graham,Matthew J Wade,Jennifer A Roberts

doi:10.3389/fmicb.2016.00419

Clare M Mccann, Casey R J Hubert + Show 4 more

Open Access

https://doi.org/10.3389/fmicb.2016.00419

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Abstract

The High Arctic is dominated by polar desert habitats whose microbial communities are poorly understood. In this study, we used next generation sequencing to describe the α- and β-diversity of microbial communities in polar desert soils from the Kongsfjorden region of Svalbard. Ten phyla dominated the soils and accounted for 95% of all sequences, with the Proteobacteria, Actinobacteria, and Chloroflexi being the major lineages. In contrast to previous investigations of Arctic soils, relative Acidobacterial abundances were found to be very low as were the Archaea throughout the Kongsfjorden polar desert landscape. Lower Acidobacterial abundances were attributed to characteristic circumneutral soil pHs in this region, which has resulted from the weathering of underlying carbonate bedrock. In addition, we compared previously measured geochemical conditions as possible controls on soil microbial communities. Phosphorus, pH, nitrogen, and calcium levels all significantly correlated with β-diversity, indicating landscape-scale lithological control of available nutrients, which in turn, significantly influenced soil community composition. In addition, soil phosphorus and pH significantly correlated with α-diversity, particularly with the Shannon diversity and Chao 1 richness indices.

Highlights

Polar soil microbiology has been understudied in comparison to temperate biomes (Bell et al, 2013; Blaud et al, 2015)
Studies of Arctic soil microbial communities to date have largely focused on comparisons of communities in active layers and underlying permafrost (Yergeau et al, 2010); soil chronosequences (Schutte et al, 2009); and most intensively, biogeochemical processes occurring in tundra soils (Høj et al, 2005; Graef et al, 2011; Tveit et al, 2013)
The dominant bacterial phyla found in the Kongsfjorden polar desert soils are consistent with the most abundant bacterial phyla observed in a global meta-analysis of soils (Janssen, 2006)

Summary

INTRODUCTION

Polar soil microbiology has been understudied in comparison to temperate biomes (Bell et al, 2013; Blaud et al, 2015). We took a more local landscape approach, studying of the influence of geochemical factors on bacterial abundances across 13 soils from the Kongsfjorden area of the Norwegian High Arctic, which included seven polar desert soils (Gray et al, 2014). Available soil P was limiting and variation in P significantly correlated with bacterial and Type I methanotroph 16S rRNA gene abundances In this current study, we have applied high-throughput amplicon sequencing to these soils with the aim of characterizing the microbial diversity (α-diversity) and community composition (β-diversity) in the seven previous polar desert soils plus two supplementary Kongsfjorden soils for comparative assessment with previous global and pan-Arctic data. An obvious question arising from our previous work (Gray et al, 2014) was whether measured geochemical variables that correlated with microbial abundances influenced overall soil microbial diversity in the polar desert soils

MATERIALS AND METHODS

RESULTS

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CONCLUSION