| Summary: | Palsa mires are elevated mounds of peat with a permanently frozen core found in areas of discontinuous permafrost. Peatlands in the subarctic, which is where these landforms are located, hold more than 30 % of the stored global soil carbon, which is a disproportionate amount considering their extent. As permafrost thaws, as a result of the subarctic region warming approximately twice as fast as the global average, this carbon might be released to the atmosphere in the form of CH4 or CO2. The aim of this study is to measure CH4 emissions on a degrading palsa in the Vissátvuopmi palsa mire complex, located in the northernmost part of Sweden, using carbon flux measurements. The 4 m tall palsa under study has been mapped with repeat Unpiloted Aerial Vehicle (UAV) LiDAR data to characterize the intra-annual subsidence of the palsa in high spatial detail. Using the flux measurements and UAV LiDAR data, correlations was investigated between CH4 fluxes and other factors such as topographic position, soil moisture, soil temperature, active layer thickness (ALT) and vegetation. The findings showed high emission of CH4 in areas where the palsa had fully collapsed, and low uptake in areas which had undergone the least amount of degradation. Surprisingly, there was low uptake to low emission in areas of the palsa which had recently degraded significantly. There was no strong correlation between flux and the other factors measured in this study (soil moisture, soil temperature, active layer thickness and type of vegetation). However, a significant difference in CH4 flux was found between plots with soil moisture <40 % and =>40 %, with higher emissions from the latter. Using available geospatial data and field observations, an estimation of the current and future CH4 emissions from the palsa was made.
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