Controls on Stable Methane Isotope Values in Northern Peatlands and Potential Shifts in Values Under Permafrost Thaw Scenarios

Abstract

Peatlands are abundant across the boreal‐Arctic landscape and are important sources of methane, a powerful greenhouse gas. The amount of methane emitted into the atmosphere depends on multiple factors including the organic material being decomposed and the microbial processes (“pathways”) that produce methane. The different pathways of methane production leave distinct fingerprints (“stable carbon isotopes”) on methane that provide information on how that methane was formed and help to trace methane in the atmosphere back to its ground source. We looked at how stable carbon isotopes change across five northern peatland locations and wanted to know what controls those changes. We found that stable carbon isotopes differ between bogs and fens and are further controlled by soil pH and the abundance of sedge vegetation present. We used this information to test how stable carbon isotopes from northern peatlands might change as the landscape becomes wetter or drier due to the impacts of climate change. We found that peatland stable carbon isotopes are most sensitive to potential landscape drying opposed to wetting which has important implications for improving methane emission models.

Citation

​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. 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. 17 p. https://doi.org/10.1029/2023JG007837.