Permafrost peatlands are a significant source of methane (CH₄) emissions to the atmosphere and could emit more CH₄ with continued permafrost thaw. Aerobic methane‐oxidizing bacteria may attenuate a substantial fraction of CH₄ emissions in thawing permafrost peatlands; however, the impact of permafrost thaw on CH₄ oxidation is uncertain. We measured potential CH₄ oxidation rates (hereafter, CH₄ oxidation) and their predictors using laboratory incubations and in situ porewater redox chemistry across a permafrost thaw gradient of eight thaw stages at Stordalen Mire, a permafrost peatland complex in northernmost Sweden. Methane oxidation rates increased across a gradient of permafrost thaw and differed in transitional thaw stages relative to end‐member stages. Oxidation was consistently higher in submerged fens than in bogs or palsas across a range of CH₄ concentrations. We also observed that CH₄ oxidation increased with decreasing in situ redox potential and was highest in sites with lower redox potential (Eh < 10 mV) and high water table. Our results suggest that redox potential can be used as an important predictor of CH₄ oxidation, especially in thawed permafrost peatlands. Our results also highlight the importance of considering transitional thaw stages when characterizing landscape‐scale CH₄ dynamics, because these transitional areas have different rates and controls of CH₄ oxidation relative to intact or completely thawed permafrost areas. As permafrost thaw increases the total area of semiwet and wet thaw stages in permafrost peatlands, CH₄ oxidation represents an important control on CH₄ emissions to the atmosphere.

中文翻译：

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融化转变和氧化还原条件驱动永久冻土泥炭地中的甲烷氧化

多年冻土的泥炭地是向大气排放甲烷（CH ₄）的重要来源，并且随着持续的冻土融化，它可能排放更多的CH ₄。需氧甲烷氧化细菌可能会减少永久冻土泥炭地融化中大部分CH ₄排放；然而，多年冻土融化对CH ₄氧化的影响尚不确定。我们测量了潜在的CH ₄氧化速率（以下称CH ₄在瑞典最北部的多年冻土泥炭地综合体Stordalen Mire中，使用实验室温育和原位孔隙水氧化还原化学方法，跨越八个解冻阶段的多年冻土融化梯度，使用它们的预测因子。甲烷氧化速率在多年冻土融化梯度范围内增加，并且在过渡融化阶段相对于末段成员阶段有所不同。在一定范围的CH ₄浓度下，淹没中的氧化始终高于沼泽或帕尔萨斯。我们还观察到，CH ₄氧化随着原位氧化还原电位的降低而增加，在氧化还原电位较低（Eh <10 mV）和地下水位较高的位置最高。我们的结果表明，氧化还原电位可以用作CH ₄的重要预测指标氧化，特别是在解冻的永久冻土泥炭地中。我们的结果也突出了在表征景观尺度CH ₄动力学时考虑过渡融化阶段的重要性，因为相对于完整或完全融化的永久冻土区，这些过渡区域对CH ₄氧化的速率和控制不同。随着多年冻土融化增加了永久冻土泥炭地的半湿融解阶段和湿融解阶段的总面积，CH ₄氧化代表了对大气中CH ₄排放的重要控制。