- 1Alfred Wegener Institute for Polar and Marine Research, Permafrost Research, Potsdam, Germany
- 2Institute of Environmental Science and Geography, University of Potsdam, Potsdam, Germany
- 3School of Forest Sciences, University of Eastern Finland, Joensuu, Finland
- 4Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
- 5Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
- 6Institute of Geosciences, University of Potsdam, Potsdam, Germany
- 7Fachbereich III Umweltingenieurwesen – Bau, Berliner Hochschule für Technik, Berlin, Germany
- 8Natural Resources Institute Finland, Joensuu, Finland
- 9Institute of Soil Science, University of Hamburg, Hamburg, Germany
- 10Center for Earth System Research and Sustainability, University of Hamburg, Hamburg, Germany
- 11Center for Landscape Research in Substainable Agricultural Futures – Land-CRAFT, Department of Agroecology, Aarhus University, Denmark
Wetlands are the largest natural source of atmospheric methane but substantial uncertainties remain in the methane budget, particularly due to the gap in spatial scales between detailed in-situ flux measurements and low-resolution land surface models. Our aim was to evaluate the importance of capturing the small-scale spatial heterogeneity of a patterned bog to accurately estimate methane emissions on the ecosystem scale throughout the year.
We used chamber measurements and pore water sampling on vegetation removal experiments at the microtopographical scale of Siikaneva bog, Southern Finland, during seasonal field campaigns in 2022. Seasonal and spatial patterns in the methane fluxes were identified alongside their environmental and ecological controls. Using high-resolution (0.06 m ground sampling distance) drone-based land cover mapping, we extrapolated the microtopographical-scale flux measurements to the ecosystem scale. Comparisons were made between methane emissions extrapolated for the whole bog area versus the footprint of a former eddy covariance system.
Spatial patterns in methane emissions differed between the seasons, as methane emissions from the wetter mud bottoms and hollows followed the seasonal cycles of peat temperature and green leaf area of aerenchymatous plants, while emissions from the drier high lawns and hummocks remained constant throughout the year. These spatial patterns of methane emissions and their seasonal variations made the magnitude and seasonal cycle of ecosystem-scale emissions highly sensitive to the distribution of microtopography types and their representation in landcover classifications. Seasonal and spatial variations in environmental drivers highlight the need for year-round methane flux measurements at the microtopography scale to improve process-based models and accurately estimate annual ecosystem-scale methane emissions. Capturing the high spatial and temporal variability of peatland methane emissions and their controls is essential for using small-scale in-situ measurements to validate low-resolution models. This approach is crucial for accurate extrapolation of small-scale data to broader spatial and temporal scales.
How to cite: Jentzsch, K., Männistö, E., Marushchak, M. E., Rettelbach, T., Golde, L., Korrensalo, A., Hashemi, J., van Delden, L., Tuittila, E.-S., Knoblauch, C., and Treat, C. C.: Spatial variation in the seasonality of methane emissions from a patterned boreal bog, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18118, https://doi.org/10.5194/egusphere-egu25-18118, 2025.
