Limited Potential for Mineralization of Permafrost Peatland Soil Carbon Following Thermokarst: Evidence From Anoxic Incubation and Priming Experiments

Permafrost thaw in peatlands risks emitting vast stores of soil organic carbon (SOC) as greenhouse gases to the atmosphere, yet anoxic conditions and low peat quality may prevent rapid SOC loss. To assess differences anaerobic mineralization following vulnerability previously-frozen peat, we incubated (5° 14°C) from 15 depths ⁓6 m cores different sites including an intact permafrost plateau thermokarst bogs that thawed ∼30 ∼200 years ago. Furthermore, a glucose-addition experiment after >700 days assessed whether labile C inputs occurring could accelerate (priming). We found common pattern rate decreasing with depth age. However, no rates among for samples similar age corresponding peatland developmental stage. Priming effects were minor short-term, did not vary or also incubations more than order magnitude higher implied field observations, suggesting should be used mainly interpret relative differences. Peat humification nitrogen phosphorous content explained 85% variability rates. influence temperature sensitivity mineralization. Overall, absence substantial priming lack between 200 ago suggests loss is unlikely.