Organic Matter Redox Status Predicts Methane Production in Boreal Peatland Ecosystems

Document Type

Article

Publication Date

10-1-2026

Abstract

Boreal peatlands are important locations of carbon storage, but the mechanisms controlling methane (CH4) production in these ecosystems are not fully understood. Reduction of redox-active organic matter (RAOM) is one understudied mechanism where microbes use solid-phase (i.e., peat) organic matter as a terminal electron acceptor in anaerobic respiration. RAOM reduction suppresses methanogenesis due to energetic favorability and is often considered as an explanation for why certain peatland ecosystems produce less CH4 than expected after accounting for other electron acceptors. Given the role of RAOM in regulating CH4 production, we compiled datasets from boreal peatlands in the USA that quantified RAOM redox state using an electron shuttling capacity (ESC) assay and evaluated how RAOM reduction predicted CH4 production in laboratory and in situ field incubations. Across all laboratory incubations, CH4 production linearly increased as RAOM was reduced, explaining 20% of average CH4 production over time. Predictive power was stronger in bogs than fens, although both produced negligible CH4 (< 0.01 μmoles) until RAOM reduction reached a certain threshold (~ 20 μmoles e−/g dw peat). In field incubations, CH4 production also linearly increased as RAOM became more reduced, explaining 60% of average CH4 production. Overall, RAOM redox state was a good predictor of CH4 production across boreal peatland ecosystems, consistent with the growing evidence suggesting that RAOM is the major terminal electron acceptor for anaerobic respiration in peatlands. Our work demonstrates that incorporating RAOM dynamics into peatland carbon cycling frameworks can help improve predictions of present and future CH4 emissions.

Publication Title

Ecosystems

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