Controls on Stable Methane Isotope Values in Northern Peatlands and Potential Shifts in Values Under Permafrost Thaw Scenarios
Kuhn, McKenzie A.; Varner, Ruth K.; McCalley, Carmody K.; Perryman, Clarice R.; Aurela, Mika; Burke, Sophia A.; Chanton, Jeffrey P.; Crill, Patrick M.; DelGreco, Jessica; Deng, Jia; Heffernan, Liam; Herrick, Christina; Hodgkins, Suzanne B.; Jones, Cheristy P.; Juutinen, Sari; Kane, Evan S.; Lamit, Louis J.; Larmola, Tuula; Lilleskov, Erik; Olefeldt, David; Palace, Michael W.; Rich, Virginia I.; Schulze, Christopher; Shorter, Joanne H.; Sullivan, Franklin B.; Sonnentag, Oliver; Turetsky, Merritt R.; Waldrop, Mark P. (2024)
Kuhn, McKenzie A.
Varner, Ruth K.
McCalley, Carmody K.
Perryman, Clarice R.
Aurela, Mika
Burke, Sophia A.
Chanton, Jeffrey P.
Crill, Patrick M.
DelGreco, Jessica
Deng, Jia
Heffernan, Liam
Herrick, Christina
Hodgkins, Suzanne B.
Jones, Cheristy P.
Juutinen, Sari
Kane, Evan S.
Lamit, Louis J.
Larmola, Tuula
Lilleskov, Erik
Olefeldt, David
Palace, Michael W.
Rich, Virginia I.
Schulze, Christopher
Shorter, Joanne H.
Sullivan, Franklin B.
Sonnentag, Oliver
Turetsky, Merritt R.
Waldrop, Mark P.
Julkaisusarja
Journal of geophysical research : biogeosciences
Volyymi
129
Numero
7
John Wiley & Sons
2024
How to cite: Kuhn, M. A., Varner, R. K., McCalley, C. K., Perryman, C. R., Aurela, M., Burke, S. A., et al. (2024). Controls on stable methane isotope values in northern peatlands and potential shifts in values under permafrost thaw scenarios. Journal of Geophysical Research: Biogeosciences, 129, e2023JG007837. https://doi.org/10.1029/2023JG007837
Julkaisun pysyvä osoite on
http://urn.fi/URN:NBN:fi-fe2024072662733
http://urn.fi/URN:NBN:fi-fe2024072662733
Tiivistelmä
Northern peatlands are a globally significant source of methane (CH4), and emissions are projected to increase due to warming and permafrost loss. Understanding the microbial mechanisms behind patterns in CH4 production in peatlands will be key to predicting annual emissions changes, with stable carbon isotopes (δ13C-CH4) being a powerful tool for characterizing these drivers. Given that δ13C-CH4 is used in top-down atmospheric inversion models to partition sources, our ability to model CH4 production pathways and associated δ13C-CH4 values is critical. We sought to characterize the role of environmental conditions, including hydrologic and vegetation patterns associated with permafrost thaw, on δ13C-CH4 values from high-latitude peatlands. We measured porewater and emitted CH4 stable isotopes, pH, and vegetation composition from five boreal-Arctic peatlands. Porewater δ13C-CH4 was strongly associated with peatland type, with δ13C enriched values obtained from more minerotrophic fens (−61.2 ± 9.1‰) compared to permafrost-free bogs (−74.1 ± 9.4‰) and raised permafrost bogs (−81.6 ± 11.5‰). Variation in porewater δ13C-CH4 was best explained by sedge cover, CH4 concentration, and the interactive effect of peatland type and pH (r2 = 0.50, p < 0.001). Emitted δ13C-CH4 varied greatly but was positively correlated with porewater δ13C-CH4. We calculated a mixed atmospheric δ13C-CH4 value for northern peatlands of −65.3 ± 7‰ and show that this value is more sensitive to landscape drying than wetting under permafrost thaw scenarios. Our results suggest northern peatland δ13C-CH4 values are likely to shift in the future which has important implications for source partitioning in atmospheric inversion models.
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