EGU21-9656
https://doi.org/10.5194/egusphere-egu21-9656
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Effects of labile carbon on anaerobic decomposition processes in permafrost wetlands

Maija E. Marushchak1, Hannu Nykänen2, Jukka Pumpanen2, A. Britta K. Sannel3, Lena Ström4, Joel White4, and Christina Biasi2
Maija E. Marushchak et al.
  • 1University of Jyväskylä, Department of Biological and Environmental Science, Jyväskylä, Finland (maija.e.marushchak@jyu.fi)
  • 2University of Kuopio, Department of Environmental and Biological and Sciences, Kuopio, Finland
  • 3Stockholm University, Department of Physical Geography, Stockholm, Sweden
  • 4Lund University, Department of Physical Geography and Ecosystem Science, Lund, Sweden

Climate warming and permafrost thaw are exposing the large carbon (C) pools of northern wetlands to enhanced decomposition, potentially increasing the release of the greenhouse gases carbon dioxide (CO2) and methane (CH4). Permafrost thaw is usually associated with changes in hydrology and vegetation: Ground collapse leads to the formation of new, productive thermokarst wetlands, and active layer deepening allows plant roots to penetrate to deeper soil layers. These processes promote interaction between old permafrost carbon and recent plant-derived carbon, but the effect of this interaction on anaerobic decomposition processes is poorly known.

Here, we report the preliminary results of a 1+-year-long soil incubation experiment where we investigated the role of fresh organics on anaerobic decomposition in arctic wetlands. We sampled mineral subsoil of Greenlandic wetland sites and the active layer and permafrost peat in a Swedish palsa mire, and incubated them with and without repeated amendments of 13C enriched glucose and cellulose. We determined the rate and isotopic composition of CO2 and CH4 with an isotopic laser, and estimated the contribution of soil organic matter decomposition vs. added carbon to the total C gas release. These results represent new understanding on how plant-derived organics change the magnitude and composition of C gas, thus affecting the climatic feedbacks from permafrost wetland C pool.

How to cite: Marushchak, M. E., Nykänen, H., Pumpanen, J., Sannel, A. B. K., Ström, L., White, J., and Biasi, C.: Effects of labile carbon on anaerobic decomposition processes in permafrost wetlands, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9656, https://doi.org/10.5194/egusphere-egu21-9656, 2021.

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