Relationships between greenhouse gas production and landscape position during short-term permafrost thaw under anaerobic conditions in the Lena Delta
Soils in the permafrost region have acted as carbon sinks for thousands of years. As a result of global warming, permafrost soils are thawing and will potentially release greenhouse gases (GHGs) such as methane (CH 4 ) and carbon dioxide (CO 2 ). However, small-scale spatial heterogeneities of GHG p...
| Published in: | Biogeosciences |
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| Main Authors: | , , , , , |
| Format: | Text |
| Language: | English |
| Published: |
2023
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| Subjects: | |
| Online Access: | https://doi.org/10.5194/bg-20-2049-2023 https://bg.copernicus.org/articles/20/2049/2023/ |
| Summary: | Soils in the permafrost region have acted as carbon sinks for thousands of years. As a result of global warming, permafrost soils are thawing and will potentially release greenhouse gases (GHGs) such as methane (CH 4 ) and carbon dioxide (CO 2 ). However, small-scale spatial heterogeneities of GHG production have been neglected in previous incubation studies. Here, we used an anaerobic incubation experiment to simulate permafrost thaw along a transect from upland Yedoma to the floodplain on Kurungnakh Island. Potential CO 2 and CH 4 production was measured during incubation of the active layer and permafrost soils at 4 and 20 ∘ C, first for 60 d (approximate length of the growing season) and then continuing for 1 year. An assessment of methanogen abundance was performed in parallel for the first 60 d. Yedoma samples from upland and slope cores remained in a lag phase during the growing season simulation, while those located in the floodplain showed high production of CH 4 ( 6.5×10 3 µ g CH 4 -C g −1 C) and CO 2 ( 6.9×10 3 µ g CO 2 -C g −1 C) at 20 ∘ C. The Yedoma samples from the permafrost layer started producing CH 4 after 6 months of incubation. We conclude that landscape position is a key factor triggering CH 4 production during the growing season time on Kurungnakh Island. |
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