Magnitude and Drivers of Potential Methane Oxidation and Production across the Tibetan Alpine Permafrost Region.

Methane (CH) dynamics across permafrost regions is critical in determining the magnitude and direction of permafrost carbon (C)-climate feedback. However, current studies are mainly derived from the Arctic area, with limited evidence from other permafrost regions. By combining large-scale laboratory incubation across 51 sampling sites with machine learning techniques and bootstrap analysis, here, we determined regional patterns and dominant drivers of CH oxidation potential in alpine steppe and meadow (CH sink areas) and CH production potential in swamp meadow (CH source areas) across the Tibetan alpine permafrost region. Our results showed that both CH oxidation potential (in alpine steppe and meadow) and CH production potential (in swamp meadow) exhibited large variability across various sampling sites, with the median value being 8.7, 9.6, and 11.5 ng g dry soil h, respectively. Our results also revealed that methanotroph abundance and soil moisture were two dominant factors regulating CH oxidation potential, whereas CH production potential was mainly affected by methanogen abundance and the soil organic carbon content, with functional gene abundance acting as the best explaining variable. These results highlight the crucial role of microbes in regulating CH dynamics, which should be considered when predicting the permafrost C cycle under future climate scenarios.