Temperature Sensitivity of Permafrost Carbon Release Mediated by Mineral and Microbial Properties

Abstract:

Temperature sensitivity (Q₁₀) of permafrost carbon (C) release upon thaw is a critical parameter for evaluating permafrost C-climate feedback. However, due to the lack of systematic measurements, it remains unclear how mineral protection interacts with microbial properties and intrinsic recalcitrance to regulate permafrost C dynamics. Based on extensive field sampling along a ~1000 km permafrost transect on the Tibetan Plateau, combined with 400-day laboratory incubation, we explore patterns and drivers of permafrost C release as well as its temperature response after thaw. We find that mineral protection and microbial properties play more important roles than substrate quality and edaphic variables in mediating permafrost C dynamics after thaw. Mineral protection weakens both C release and Q₁₀. Higher microbial abundances and activities promote C release and Q₁₀, whereas higher microbial diversity results in lower Q₁₀. These findings highlight the dual role of microbial properties in regulating permafrost C dynamics and the crucial role of organo-mineral associations in attenuating permafrost C-climate feedback.