Microbial diversity and biogeography in Arctic soils

Abstract

Microorganisms dominate terrestrial environments in the polar regions and Arctic soils are known to harbour significant microbial diversity, far more diverse and numerous in the region than was once thought. Furthermore, the geographic distribution and structure of Arctic microbial communities remains elusive, despite their important roles in both biogeochemical cycling and in the generation and decomposition of climate active gases. Critically, Arctic soils are estimated to store over 1500 Pg of carbon and, thus, have the potential to generate positive feedback within the climate system. As the Arctic region is currently undergoing rapid change, the likelihood of faster release of greenhouse gases such as CO , CH and N O is increasing. Understanding the microbial communities in the region, in terms of their diversity, abundance and functional activity, is key to producing accurate models of greenhouse gas release. This review brings together existing data to determine what we know about microbial diversity and biogeography in Arctic soils.

Increasing Organic Carbon Biolability With Depth in Yedoma Permafrost: Ramifications for Future Climate Change

“…At the VC permafrost tunnel, archaeal diversity was dominated by the Soil Crenarchaeotic Group (SCG; Thaumarchaeota ; up to 70.9% relative abundance) and Methanosarcinales (up to 52.6% relative abundance). Prior studies have also found large abundances of Methanomicrobia in Alaskan soils (Malard & Pearce, ). Methanogens have also been detected in buried yedoma permafrost in northeast Russian (Bischoff et al, ; Rivkina et al, ) and the CRREL permafrost tunnel in Fox, AL (Mackelprang et al, ).…”

“…Following thaw, suitable conditions could allow for the activation of microbial communities, including methanogens, and subsequent GHG production (Knoblauch et al, 2018;Mackelprang et al, 2011;Wei et al, 2018). However, microbial communities in deep permafrost remain a relatively unknown component, and we cannot currently predict how microbes will use permafrost OC following thaw (Graham et al, 2012;Malard & Pearce, 2018).…”

Soil pH and temperature regulate assembly processes of abundant and rare bacterial communities in agricultural ecosystems

“…We can also make ecological inferences using phylogenetic turnover (Cavender-Bares et al, 2009;Tripathi et al, 2018). Microbial diversity of extreme ecosystems, like Arctic soils, could be substantially different, while other non-extreme environments, for example, forest and agricultural fields, may harbour similar communities (Malard and Pearce, 2018). Long-term crop cultivation (e.g.…”

Extreme environments: microbiology leading to specialized metabolites

“…The dominant cyanobacterial orders in Arctic soil crusts were found to be the Nostocales, Oscillatoriales and Synechococcales (Steven et al ; Pushkareva et al ). Indeed, cyanobacteria are mainly responsible for the uptake of CO 2 and N 2 as plants in Arctic ecosystems are unable to fix nitrogen (Malard and Pearce ).…”

“…Archaea have also been isolated from permafrost (Jansson and Taş ). Archaeal communities in Arctic soils seem to be variable through Methanobacteria and Methanomicrobia ( Euryarchaeota ) are abundant in Alaskan and Greenland soils (Ganzert et al ; Malard and Pearce ), whereas isolates related to the genera Methanolobus and Methanomethylovorans have been recovered from frozen ground in the Zoige wetland of the Qinghai—Tibet plateau (Zhang et al ). The methane released by these organisms can be used as a sole carbon source by methanotrophic bacteria, such as α‐ and γ‐proteobacteria (Coolen et al ) and members of the Methanococcales (Martineau et al ).…”