Relationships between greenhouse gas production and landscape position during short-term permafrost thaw under anaerobic conditions in the Lena Delta

• Published in: Biogeosciences
• Main Authors: Laurent, Mélissa, Fuchs, Matthias, Herbst, Tanja, Runge, Alexandra, Liebner, Susanne, Treat, Claire C
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Copernicus GmbH 2023
• Subjects: lena delta; permafrost
• Online Access: https://epic.awi.de/id/eprint/57792/; https://epic.awi.de/id/eprint/57792/1/Laurent_etal_2023_Biogeosci.pdf; https://hdl.handle.net/10013/epic.d3ff2072-6dfa-44eb-b029-38d1d99f917b

Soils in the permafrost region have acted as car- bon 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 (CH4) and carbon dioxide (CO2). 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 CO2 and CH4 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 CH4 (6.5 × 103 μg CH4-C g−1 C) and CO2 (6.9 × 103 μg CO2-C g−1 C) at 20 ◦C. The Yedoma samples from the permafrost layer started producing CH4 after 6 months of incubation. We conclude that landscape position is a key factor triggering CH4 production during the growing season time on Kurungnakh Island.