EGU2020-17683
https://doi.org/10.5194/egusphere-egu2020-17683
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Microbial life in collapsing permafrost in NE Greenland

Maria Scheel1, Torben R. Christensen1, Mats Rundgren2, Carsten Suhr Jacobsen3, and Athanasios Zervas3
Maria Scheel et al.
  • 1Arctic Research Centre (ARC), Aarhus University, Aarhus, Denmark (bios@au.dk)
  • 2Quaternary Sciences, Lund University, Lund, Sweden
  • 3Department of Environmental Science, Aarhus University, Roskilde, Denmark (envs@au.dk)

In recent years, permafrost-affected soils have been shown to be gradually subject of thawing (IPCC, 2019). Formerly frozen soil organic carbon stocks hence become increasingly susceptible to microbial decomposition and transformation into greenhouse gases (Schuur et al., 2015). An estimated 20% of Arctic permafrost areas are subject of melting of belowground ice and consequent collapse (Olefeldt et al. 2016), but these thermokarst landscapes are often difficult to assess.

In 2018, a thermokarst developed into a thermal erosion gully in close vicinity to the Zackenberg Research Station. As one of the main stations of the Greenland Ecosystem Monitoring (GEM) program, the monitoring of various ecosystem parameters at this site during the past 25 years, including hydrology, soil temperature and active layer depth, enables a spatiotemporally precise description of the thermokarst's physical progression.

In order to characterize the development of a thermokarst soil microbial community and understand its spatial distribution and taxonomic biodiversity, soil cores of 30 cm above and below an ice lens were extracted in August 2018, as well as after a dry and warm summer season in September 2019, until 90 cm depth to also sample still frozen permafrost soils. Soil characterization included loss on ignition, radiocarbon dating and microbial viability assays for both years. Bacterial 16S rDNA V3-V4 and fungal ITS1 gene region amplicons of extracted DNA were sequenced and analyzed. With the microbiome involved in biochemical processes such as nitrogen fixation, methane production and oxidation as well as CO2 respiration, knowledge about abundance, genetic and adaptation potential of bacteria, archaea and microeukaryotes in fast changing permafrost soils affects several ecosystem carbon fluxes significantly.

This work is part of a project, describing both the taxonomic and functional composition of this thermokarst microbiome, including the use of multi-omics to reveal the carbon cycling gene potential and expression in combination with in situ and laboratory incubation gas fluxes of CO2, N2O and CH4. These biological and biogeochemical insights from this event are put into perspective with long-term, maintained data supplied by the GEM. 

How to cite: Scheel, M., Christensen, T. R., Rundgren, M., Suhr Jacobsen, C., and Zervas, A.: Microbial life in collapsing permafrost in NE Greenland, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-17683, https://doi.org/10.5194/egusphere-egu2020-17683, 2020

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