Metagenomes from Thawing Low-Soil-Organic-Carbon Mineral Cryosols and Permafrost of the Canadian High Arctic

Chauhan, Archana; Layton, Alice C.; Vishnivetskaya, Tatiana A.; Williams, Daniel E.; Pfiffner, Susan M.; Rekepalli, Bhanu; Stackhouse, B. T.; Lau, Maggie C. Y.; Phelps, Tommy J.; Mykytczuk, Nadia; Ronholm, Jennifer; Whyte, Lyle G.; Onstott, Tullis C.; Sayler, Gary S.

doi:10.1128/genomea.01217-14

Cited by 24 publications

(21 citation statements)

References 5 publications

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“…Sequence abundance information from metagenomic data gathered from the 5‐cm cryosol samples from the same site (Chauhan et al ., ; Stackhouse et al ., ) was used to estimate that the total methanotrophic population should account for up to ~1% of the cellular community with a higher proportion of type II methanotrophs at the surface (~0.8% of total sequences) than in the permafrost (~0.1% of total sequences). Total counts of bacterial, archaeal, and eukaryotic cells determined by FISH averaged 9.8 ± 5.2 × 10 8 cells g −1 , with bacteria accounting for 82 ± 11% of cell counts and no statistical difference between depths ( P = 0.46, Fig.…”

Section: Resultsmentioning

confidence: 99%

Atmospheric CH₄ oxidation by Arctic permafrost and mineral cryosols as a function of water saturation and temperature

et al. 2016

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The response of methanotrophic bacteria capable of oxidizing atmospheric CH to climate warming is poorly understood, especially for those present in Arctic mineral cryosols. The atmospheric CH oxidation rates were measured in microcosms incubated at 4 °C and 10 °C along a 1-m depth profile and over a range of water saturation conditions for mineral cryosols containing type I and type II methanotrophs from Axel Heiberg Island (AHI), Nunavut, Canada. The cryosols exhibited net consumption of ~2 ppmv CH under all conditions, including during anaerobic incubations. Methane oxidation rates increased with temperature and decreased with increasing water saturation and depth, exhibiting the highest rates at 10 °C and 33% saturation at 5 cm depth (260 ± 60 pmol CH gdw d ). Extrapolation of the CH oxidation rates to the field yields net CH uptake fluxes ranging from 11 to 73 μmol CH m d , which are comparable to field measurements. Stable isotope mass balance indicates ~50% of the oxidized CH is incorporated into the biomass regardless of temperature or saturation. Future atmospheric CH uptake rates at AHI with increasing temperatures will be determined by the interplay of increasing CH oxidation rates vs. water saturation and the depth to the water table during summer thaw.

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Section: Resultsmentioning

confidence: 99%

Atmospheric CH₄ oxidation by Arctic permafrost and mineral cryosols as a function of water saturation and temperature

et al. 2016

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“…A sulfur-reducing bacterium was isolated from ancient permafrost (Vatsurina et al 2008), and 16S rRNA gene sequences from sulfate-reducing and sulfur-oxidizing bacteria were found in permafrost (Hansen et al 2007, Steven et al 2007). Taxonomic assignment of metagenomic sequences to sulfate reducers and the presence of genes involved in sulfate reduction also revealed that microbes that use sulfate as a TEA are present in permafrost (Chauhan et al 2014, Lipson et al 2013.…”

Section: Sulfur Cyclementioning

confidence: 98%

Permafrost Meta-Omics and Climate Change

Mackelprang

Saleska²,

Jacobsen

et al. 2016

Annu. Rev. Earth Planet. Sci.

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Permanently frozen soil, or permafrost, covers a large portion of the Earth's terrestrial surface and represents a unique environment for cold-adapted microorganisms. As permafrost thaws, previously protected organic matter becomes available for microbial degradation. Microbes that decompose soil carbon produce carbon dioxide and other greenhouse gases, contributing substantially to climate change. Next-generation sequencing and other -omics technologies offer opportunities to discover the mechanisms by which microbial communities regulate the loss of carbon and the emission of greenhouse gases from thawing permafrost regions. Analysis of nucleic acids and proteins taken directly from permafrost-associated soils has provided new insights into microbial communities and their functions in Arctic environments that are increasingly impacted by climate change. In this article we review current information from various molecular -omics studies on permafrost microbial ecology and explore the relevance of these insights to our current understanding of the dynamics of permafrost loss due to climate change.

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“…Archaea have also been observed in Arctic and Antarctic soils, albeit at very low abundance [39][40][41]. Low abundance levels are not necessarily indicative of the functional importance of these taxa, as the archaeal taxa identified are typically associated with unique functional properties, such as methanogenesis [42 ].…”

Section: Microbial Diversity In Cold Environmentsmentioning

confidence: 99%

“…However, very few studies have assessed the diversity of viruses in cold environments, let alone their functional roles. Of these published studies on polar habitats, mostly focus on lacustrine systems [54,55] with only very limited surveys of polar edaphic metaviromes [40,56]. The latter suggests that viruses in cold soil environments are highly diverse but are typically dominated by Mycobacterium phages [56].…”

Section: Microbial Diversity In Cold Environmentsmentioning

confidence: 99%

Microbial diversity and functional capacity in polar soils

Makhalanyane

Goethem

Cowan

2016

Current Opinion in Biotechnology

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Global change is disproportionately affecting cold environments (polar and high elevation regions), with potentially negative impacts on microbial diversity and functional processes. In most cold environments the combination of low temperatures, and physical stressors, such as katabatic wind episodes and limited water availability result in biotic systems, which are in trophic terms very simple and primarily driven by microbial communities. Metagenomic approaches have provided key insights on microbial communities in these systems and how they may adapt to stressors and contribute towards mediating crucial biogeochemical cycles. Here we review, the current knowledge regarding edaphic-based microbial diversity and functional processes in Antarctica, and the Artic. Such insights are crucial and help to establish a baseline for understanding the impact of climate change on Polar Regions. AddressCentre for Microbial Ecology and Genomics, Department of Genetics, University of Pretoria, Pretoria 0028, South Africa Corresponding author: Cowan, Don Arthur (don.cowan@up.ac.za) IntroductionThe Congress of Parties (COP) 21 meeting in Paris (November 2015) highlighted the urgency of global climate change, and the critical need to reduce global average temperatures through curbing greenhouse gas emissions [1]. Nowhere are the effects of global change more apparent than in cold environments (polar and alpine regions), which are subject to accelerated rates of warming compared to other ecosystems [2 ,3]. Climatic models have predicted that temperatures in high latitude regions of the Northern Hemisphere are likely to increase by between 0.38C and 4.88C before the end of the twenty first century [4]. There is also evidence that regions in the Southern Hemisphere have experienced the fastest warming globally, with average increases of as much as 2.48C in the last fifty years [5].A major consequence of climate change in cold environments is the thawing of submerged and surface ice, which alters the hydrology of the systems and may have adverse effects on microbial processes [6 ]. In cold environments, microorganisms (bacteria, archaea and fungi) are major constituents of the total biomass, and are estimated to mediate the cycling of key biogeochemical elements such as nitrogen and carbon, with potentially important implications for the productivity of these systems [7]. Although the precise contribution of microbial processes to global change processes are not well known, there are efforts to incorporate biological processes into Earth systems models with the realization that they may be crucial in regulating soil organic matter (SOM) [8 ]. For instance, permafrost (defined as ground which remains frozen for at least two years) in cold environments stores roughly 1600 Pg of carbon, which if released would significantly contribute towards increasing global CO 2 levels [9]. The current contribution of microbial communities to constraining carbon losses in permafrost and the influence on CO 2 levels remains virtually unknown. In ...

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Metagenomes from Thawing Low-Soil-Organic-Carbon Mineral Cryosols and Permafrost of the Canadian High Arctic

Cited by 24 publications

References 5 publications

Atmospheric CH₄ oxidation by Arctic permafrost and mineral cryosols as a function of water saturation and temperature

Atmospheric CH₄ oxidation by Arctic permafrost and mineral cryosols as a function of water saturation and temperature

Permafrost Meta-Omics and Climate Change

Microbial diversity and functional capacity in polar soils

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Metagenomes from Thawing Low-Soil-Organic-Carbon Mineral Cryosols and Permafrost of the Canadian High Arctic

Cited by 24 publications

References 5 publications

Atmospheric CH4 oxidation by Arctic permafrost and mineral cryosols as a function of water saturation and temperature

Atmospheric CH4 oxidation by Arctic permafrost and mineral cryosols as a function of water saturation and temperature

Permafrost Meta-Omics and Climate Change

Microbial diversity and functional capacity in polar soils

Contact Info

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Atmospheric CH₄ oxidation by Arctic permafrost and mineral cryosols as a function of water saturation and temperature

Atmospheric CH₄ oxidation by Arctic permafrost and mineral cryosols as a function of water saturation and temperature