EGU24-16094, updated on 09 Mar 2024
EGU General Assembly 2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Seasonal controls on methane flux components in a boreal peatland - combining plant removal and stable isotope analyses

Katharina Jentzsch1, Elisa Männistö2, Maija E. Marushchak3,4, Aino Korrensalo4,5, Lona van Delden1, Eeva-Stiina Tuittila2, Christian Knoblauch6,7, and Claire C. Treat1
Katharina Jentzsch et al.
  • 1Alfred-Wegener Institute Helmholtz Center for Polar and Marine Research, Potsdam, Germany
  • 2School of Forest Sciences, University of Eastern Finland, Joensuu, Finland
  • 3Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
  • 4Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
  • 5Natural Resources Institute Finland, Joensuu, Finland
  • 6Institute of Soil Science, Universität Hamburg, Hamburg, Germany
  • 7Center for Earth System Research and Sustainability, Universität Hamburg, Hamburg, Germany

Wetlands are the largest natural source of atmospheric methane and highly vulnerable to climate change. In our study we aim to better understand the environmental controls on the strength and seasonal variation of methane flux components from hollows, typically the high-emitting wettest microtopographic features in a boreal bog. We measured methane fluxes from intact vegetation as well as on vegetation removal treatments and analyzed pore water methane concentrations and stable carbon isotopes of dissolved and emitted methane. Using these data, we quantified the rates of total methane emission, methane oxidation and plant-mediated methane transport for the summer and shoulder seasons of 2021 and 2022. Total methane emissions from areas with intact vegetation range from 13 to 2171 mgCH4 m–2 d–1 during shoulder seasons and summer months and are mainly controlled by the leaf area of aerenchymatous plants. Methane oxidation in the Sphagnum moss layer decreases total methane emissions by 82 ± 20 % while transport of methane through aerenchymatous plants increases methane emissions by 80 ± 22 %. Both methane oxidation and plant-mediated methane transport rates follow a seasonal cycle with lower but still significant rates during the shoulder seasons compared to the summer months. As a net effect, the presence of Sphagnum mosses and vascular plants reduces methane emissions from the study site. This balance, however, appears to be highly sensitive to climate change, i.e. increasing soil temperatures and changing leaf area and composition of the wetland vegetation. The provided insights can help to improve the representation of environmental controls on the methane cycle and its seasonal dynamics in process-based models to more accurately predict future methane emissions from boreal peatlands.

How to cite: Jentzsch, K., Männistö, E., Marushchak, M. E., Korrensalo, A., van Delden, L., Tuittila, E.-S., Knoblauch, C., and Treat, C. C.: Seasonal controls on methane flux components in a boreal peatland - combining plant removal and stable isotope analyses, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16094,, 2024.

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