Spatial variation of net methane uptake in Arctic and subarctic drylands of Canada and Greenland
The importance of uptake of atmospheric methane (CH 4 ) in dry Arctic soils for the total Arctic CH 4 budget is unresolved. This is partly due to lack of data on the spatial variability of net CH 4 consumption and understanding of the main process drivers. We measured net CH 4 consumption in Arctic...
Published in: | Geoderma |
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Main Authors: | , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2024
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Subjects: | |
Online Access: | https://pure.au.dk/portal/en/publications/de8e4b78-2734-4c8b-b9ba-82f9da2d4e25 https://doi.org/10.1016/j.geoderma.2024.116815 http://www.scopus.com/inward/record.url?scp=85186437824&partnerID=8YFLogxK |
Summary: | The importance of uptake of atmospheric methane (CH 4 ) in dry Arctic soils for the total Arctic CH 4 budget is unresolved. This is partly due to lack of data on the spatial variability of net CH 4 consumption and understanding of the main process drivers. We measured net CH 4 consumption in Arctic and subarctic landscapes located in in Disko Bay Area and Kangerlussuaq in Western Greenland and in the St. Elias Range in the Yukon, Canada, respectively. Our aim was to characterize the in situ spatial variability of net CH 4 uptake in hitherto unexplored Arctic dry upland soils to explore possible limits and environmental drivers across the Arctic geodiversity. Furthermore, we sampled soil for incubation experiments to investigate how net CH 4 oxidation responded to changes in soil moisture in contrasting geomorphic settings and parent geological parent materials. We used a laser-based fast deployable chamber system for flux measurements. All studied sites were net sinks of atmospheric CH 4 with an average flux −7.5 ± 5.6 μmol CH 4 m -2 h −1 , that are in the upper range of reported net CH 4 uptake fluxes in similar soils of the Arctic. The large observed spatial variability within all studied sites (coefficient of variation 50 – 120 %) highlights the need for careful research design allowing for many spatial replicates to achieve representative values. Sites with an active geomorphic environment (abrasion plateau, riverbeds, mountain tops) generally had lower than average net CH 4 uptake. Our incubation studies revealed that subsurface CH4 oxidation is the main driver of net surface-atmosphere exchange and that net CH 4 oxidation in these layers responded more to changes to soil moisture than in near surface layers. Our study shows surprisingly similar flux magnitudes of net CH 4 uptake across widely different landscape forms and geologic parent material, but responding similarly to soil hydrology and geomorphic disturbance, indicating global controls on the net CH 4 oxidation in these dry upland environments. |
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