Measurement of the 13 C isotopic signature of methane emissions from Northern European wetlands ...

• Main Authors: Fisher, RE, France, JL, Lowry, D, Lanoisellé, M, Brownlow, R, Pyle, JA, Cain, M, Warwick, N, Skiba, UM, Drewer, J, Dinsmore, KJ, Leeson, Bauguitte, SJ-B, Wellpott, A, O'Shea, SJ, Allen, G, Gallagher, MW, Pitt, J, Percival, CJ, Bower, K, George, C, Hayman, GD, Aalto, T, Lohila, A, Aurela, M, Laurila, T, Crill, PM, McCalley, CK, Nisbet, EG
• Format: Article in Journal/Newspaper
• Language: English
• Published: AGU 2017
• Subjects: methane; wetlands; isotopes; Arctic; Fennoscandian
• Online Access: https://dx.doi.org/10.17863/cam.8550; https://www.repository.cam.ac.uk/handle/1810/263233

Isotopic data provide powerful constraints on regional and global methane emissions and their source profiles. However, inverse modeling of spatially-resolved methane flux is currently constrained by a lack of information on the variability of source isotopic signatures. In this study, isotopic signatures of emissions in the Fennoscandian Arctic have been determined in chambers over wetland, in the air 0.3 to 3 m above the wetland surface and by aircraft sampling from 100 m above wetlands up to the stratosphere. Overall the methane flux to atmosphere has a coherent δ13C isotopic signature of -71 ± 1‰, measured in situ on the ground in wetlands. This is in close agreement with δ13C isotopic signatures of local and regional methane increments measured by aircraft campaigns flying through air masses containing elevated methane mole fractions. In contrast results from wetlands in Canadian boreal forest further south gave isotopic signatures of -67 ± 1 ‰. Wetland emissions dominate the local methane source ...