Soil Microbial Community Response to Permafrost Degradation in Palsa Fields of the Hudson Bay Lowlands: Implications for Greenhouse Gas Production in a Warming Climate

Kirkwood, J. Adam. H.; Roy-Léveillée, Pascale; Mykytczuk, Nadia; Packalen, Maara S.; McLaughlin, Jim; Laframboise, Amy; Basiliko, Nathan

doi:10.1029/2021gb006954

Cited by 8 publications

(6 citation statements)

References 82 publications

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“…Surprisingly, per horizon, our prokaryotic alpha diversity measurements were 1.5–2 times higher compared to their data. We hypothesized this to be simply based on varying methodological approaches, as we used ASVs instead of OTUs, increasing the number of unique sequences, which only a few permafrost erosion studies did previously ( Doherty et al, 2020 ; Holm et al, 2020 ; Kirkwood et al, 2021 ).…”

Section: Discussionmentioning

confidence: 99%

Microbial Community Changes in 26,500-Year-Old Thawing Permafrost

et al. 2022

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Northern permafrost soils store more than half of the global soil carbon. Frozen for at least two consecutive years, but often for millennia, permafrost temperatures have increased drastically in the last decades. The resulting thermal erosion leads not only to gradual thaw, resulting in an increase of seasonally thawing soil thickness, but also to abrupt thaw events, such as sudden collapses of the soil surface. These could affect 20% of the permafrost zone and half of its organic carbon, increasing accessibility for deeper rooting vegetation and microbial decomposition into greenhouse gases. Knowledge gaps include the impact of permafrost thaw on the soil microfauna as well as key taxa to change the microbial mineralization of ancient permafrost carbon stocks during erosion. Here, we present the first sequencing study of an abrupt permafrost erosion microbiome in Northeast Greenland, where a thermal erosion gully collapsed in the summer of 2018, leading to the thawing of 26,500-year-old permafrost material. We investigated which soil parameters (pH, soil carbon content, age and moisture, organic and mineral horizons, and permafrost layers) most significantly drove changes of taxonomic diversity and the abundance of soil microorganisms in two consecutive years of intense erosion. Sequencing of the prokaryotic 16S rRNA and fungal ITS2 gene regions at finely scaled depth increments revealed decreasing alpha diversity with depth, soil age, and pH. The most significant drivers of variation were found in the soil age, horizons, and permafrost layer for prokaryotic and fungal beta diversity. Permafrost was mainly dominated by Proteobacteria and Firmicutes, with Polaromonas identified as the most abundant taxon. Thawed permafrost samples indicated increased abundance of several copiotrophic phyla, such as Bacteroidia, suggesting alterations of carbon utilization pathways within eroding permafrost.

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Section: Discussionmentioning

confidence: 99%

Microbial Community Changes in 26,500-Year-Old Thawing Permafrost

et al. 2022

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“…Furthermore, studies indicate that hydrogenotrophic and acetoclastic pathways dominate in permafrost bogs and fens, respectively 53 . In environments of thawing permafrost, either acetoclastic or hydrogenotrophic methane production can be enhanced, depending on different sites or stages of permafrost degradation 63–65 . Several environmental factors, such as soil moisture content, carbon quality and availability, soil temperature, and vegetation communities, influence the predominant pathways of methanogenesis 30,66–68 .…”

Section: Microbes In Permafrost Soilsmentioning

confidence: 99%

Carbon‐cycling microorganisms in permafrost and their responses to a warming climate: A review

Yang,

Wen,

et al. 2023

Permafrost & Periglacial

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Global climate warming is accelerating permafrost degradation. The large amounts of soil organic matter in permafrost‐affected soils are prone to increased microbial decomposition in a warming climate. Along with permafrost degradation, changes to the soil microbiome play a crucial role in enhancing our understanding and in predicting the feedback of permafrost carbon. In this article, we review the current state of knowledge of carbon‐cycling microbial ecology in permafrost regions. Microbiomes in degrading permafrost exhibit variations across spatial and temporal scales. Among the short‐term, rapid degradation scenarios, thermokarst lakes have distinct biogeochemical conditions promoting emission of greenhouse gases. Additionally, extreme climatic events can trigger drastic changes in microbial consortia and activity. Notably, environmental conditions appear to exert a dominant influence on microbial assembly in permafrost ecosystems. Furthermore, as the global climate is closely connected to various permafrost regions, it will be crucial to extend our understanding beyond local scales, for example by conducting comparative and integrative studies between Arctic permafrost and alpine permafrost on the Qinghai–Tibet Plateau at global and continental scales. These comparative studies will enhance our understanding of microbial functioning in degrading permafrost ecosystems and help inform effective strategies for managing and mitigating the impacts of climate change on permafrost regions.

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“…Both recently thawed (young) and mature thermokarst bogs have distinct hydrological regimes, vegetation communities, and peat chemistry. Following thaw, associated changes in vegetation and litter input alters microbial community composition and activity (Adamczyk, Perez-Mon, Gunz, & Frey, 2020;Kirkwood et al, 2021). Such changes in microbial community structure thus impact CH4 emissions from thermokarst peatlands.…”

Section: Production and Emissions Of Ch4 Along A Peatland Thaw Gradientmentioning

confidence: 99%

High peatland methane emissions following permafrost thaw: enhanced acetoclastic methanogenesis during early successional stages

Heffernan

Cavaco

Bhatia

et al. 2022

Preprint

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Abstract. Permafrost thaw in northern peatlands often leads to increased methane (CH4) emissions, but gaps remain in our understanding of the underlying controls responsible for increased emissions and the duration for which they persist. We assessed how shifting ecological conditions affect microbial communities, and the magnitude and stable isotopic signature (δ13C) of CH4 emissions along a thermokarst bog transect in boreal western Canada. Thermokarst bogs develop following permafrost thaw when dry, elevated peat plateaus collapse and become saturated and dominated by Sphagnum mosses. We differentiated between a young and a mature thermokarst bog stage (~30 and years ~200 since thaw, respectively). The young bog located along the thermokarst edge, was wetter, warmer and dominated by hydrophilic vegetation compared to the mature bog. Using 16S rRNA gene high throughput sequencing, we show that microbial communities were distinct near the surface and converged with depth, but lesser differences remained down to the lowest depth (160 cm). Microbial community analysis and δ13C data from CH4 surface emissions and dissolved gas depth profiles show that hydrogenotrophic methanogenesis was the dominant pathway at both sites. However, the young bog was found to have isotopically heavier δ13C-CH4 in both dissolved gases profiles and surface CH4 emissions, suggesting that acetoclastic methanogenesis was relatively more enhanced throughout the young bog peat profile. Furthermore, young bog CH4 emissions were three times greater than the mature bog. Our study suggests that interactions between ecological conditions and methanogenic communities enhance CH4 emissions in young thermokarst bogs, but these favorable conditions only persist for the initial decades after permafrost thaw.

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Soil Microbial Community Response to Permafrost Degradation in Palsa Fields of the Hudson Bay Lowlands: Implications for Greenhouse Gas Production in a Warming Climate

Cited by 8 publications

References 82 publications

Microbial Community Changes in 26,500-Year-Old Thawing Permafrost

Microbial Community Changes in 26,500-Year-Old Thawing Permafrost

Carbon‐cycling microorganisms in permafrost and their responses to a warming climate: A review

High peatland methane emissions following permafrost thaw: enhanced acetoclastic methanogenesis during early successional stages

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