Plants,microorganisms, and soil temperatures contribute to a decrease in methane fluxes on a drained Arctic floodplain |
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| Authors: | Min Jung Kwon Felix Beulig Iulia Ilie Marcus Wildner Kirsten Küsel Lutz Merbold Miguel D Mahecha Nikita Zimov Sergey A Zimov Martin Heimann Edward A G Schuur Joel E Kostka Olaf Kolle Ines Hilke Mathias Göckede |
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| Institution: | 1. Max Planck Institute for Biogeochemistry, Hans‐Kn?ll‐Str 10, 07745 Jena, Germany;2. Aquatic Geomicrobiology, Institute of Ecology, Friedrich Schiller University Jena, Dornburgerstr 159, 07743 Jena, Germany;3. Geoecology–Environmental Science: Micrometeorology and Atmospheric Chemistry, Faculty of Biology, Chemistry and Earth Science, University of Bayreuth, Universit?tsstr 30, 95447 Bayreuth, Germany;4. German Centre for Integrative Biodiversity Research (iDiv), Leipzig, Germany;5. Department of Environmental Systems Science, Institute of Agricultural Sciences, ETH Zurich, Universit?tstr 16, 8092 Zürich, Switzerland;6. North‐East Science Station, Pacific Institute for Geography, Far‐Eastern Branch of Russian Academy of Science, PO Box 18, Cherskii, Republic of Sakha (Yakutia), Russia;7. Division of Atmospheric Sciences, Department of Physics, PO Box 64, FI‐00014 University of Helsinki, Helsinki, Finland;8. Center for Ecosystem Science and Society, Department of Biological Sciences, Northern Arizona University, PO Box 5620, Flagstaff, AZ 86011, USA;9. School of Biology, Georgia Institute of Technology, North Avenue, Atlanta, GA 30332, USA |
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| Abstract: | As surface temperatures are expected to rise in the future, ice‐rich permafrost may thaw, altering soil topography and hydrology and creating a mosaic of wet and dry soil surfaces in the Arctic. Arctic wetlands are large sources of CH4, and investigating effects of soil hydrology on CH4 fluxes is of great importance for predicting ecosystem feedback in response to climate change. In this study, we investigate how a decade‐long drying manipulation on an Arctic floodplain influences CH4‐associated microorganisms, soil thermal regimes, and plant communities. Moreover, we examine how these drainage‐induced changes may then modify CH4 fluxes in the growing and nongrowing seasons. This study shows that drainage substantially lowered the abundance of methanogens along with methanotrophic bacteria, which may have reduced CH4 cycling. Soil temperatures of the drained areas were lower in deep, anoxic soil layers (below 30 cm), but higher in oxic topsoil layers (0–15 cm) compared to the control wet areas. This pattern of soil temperatures may have reduced the rates of methanogenesis while elevating those of CH4 oxidation, thereby decreasing net CH4 fluxes. The abundance of Eriophorum angustifolium, an aerenchymatous plant species, diminished significantly in the drained areas. Due to this decrease, a higher fraction of CH4 was alternatively emitted to the atmosphere by diffusion, possibly increasing the potential for CH4 oxidation and leading to a decrease in net CH4 fluxes compared to a control site. Drainage lowered CH4 fluxes by a factor of 20 during the growing season, with postdrainage changes in microbial communities, soil temperatures, and plant communities also contributing to this reduction. In contrast, we observed CH4 emissions increased by 10% in the drained areas during the nongrowing season, although this difference was insignificant given the small magnitudes of fluxes. This study showed that long‐term drainage considerably reduced CH4 fluxes through modified ecosystem properties. |
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| Keywords: | aerenchyma closed dynamic chamber fall methane fluxes methanogens Siberia |
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