The dramatic changes in precipitation patterns on the Tibetan Plateau affected the carbon-sequestering microbial communities within wetland ecosystems, which were closely related to the responses and adaptation mechanisms of alpine wetland ecosystems to climate change. This study focused on wetland soils subjected to different precipitation gradient treatments and employed high-throughput sequencing technology to analyze the soil cbbM carbon-sequestering microbial communities. The results indicated that Proteobacteria were the dominant microbial community responsible for carbon sequestration in the Wayan Mountain wetland. A 50% increase in precipitation significantly raised the soil moisture content, while a 50% reduction and a 25% increase in precipitation notably enhanced the total soil carbon content. The 25% reduction in precipitation increased the differences in microbial community composition, whereas both the 50% increase and the 50% reduction in precipitation decreased these differences. The soil pH and temperature had the most significant impact on the carbon-sequestering microbial communities. In conclusion, changes in precipitation affect the cbbM carbon sequestration characteristics of soil microbial communities, and a moderate reduction in water input benefited carbon sequestration in wetlands.

Global climate warming has led to the deepening of the active layer of permafrost on the Tibetan Plateau, further triggering thermal subsidence phenomena, which have profound effects on the carbon cycle of regional ecosystems. This study conducted warming (W) and thermal subsidence (RR) control experiments using an Open-Top Chamber (OTC) device in the river source wetlands of the Qinghai Lake basin. The aim was to assess the impacts of warming and thermal subsidence on soil temperature, volumetric water content, biomass, microbial diversity, and soil respiration (both autotrophic and heterotrophic respiration). The results indicate that warming significantly increased soil temperature, especially during the colder seasons, and thermal subsidence treatment further exacerbated this effect. Soil volumetric water content significantly decreased under thermal subsidence, with the RRW treatment having the most pronounced impact on moisture. Additionally, a microbial diversity analysis revealed that warming promoted bacterial richness in the surface soil, while thermal subsidence suppressed fungal community diversity. Soil respiration rates exhibited a unimodal curve during the growing season. Warming treatment significantly reduced autotrophic respiration rates, while thermal subsidence inhibited heterotrophic respiration. Further analysis indicated that under thermal subsidence treatment, soil respiration was most sensitive to temperature changes, with a Q₁₀ value reaching 7.39, reflecting a strong response to climate warming. In summary, this study provides new scientific evidence for understanding the response mechanisms of soil carbon cycling in Tibetan Plateau wetlands to climate warming.