As important carbon sinks, alpine wetlands on the Tibetan Plateau are undergoing severe degradation. To reveal warming-induced ecological shifts in alpine environments, this study determined soil nutrient contents, enzyme activities, absorption and fluorescence spectra and quadrupole time-of-flight mass spectra (metabolomes) of dissolved organic matter (DOM) and metagenomes based on short-term incubation (0 °C, 10 °C and 20 °C) of topsoil from alpine wetlands and meadows (degraded wetlands). Compared with meadows, wetlands had higher contents of soil DOM (dissolved organic carbon, dissolved organic nitrogen and dissolved phosphorous) and greater activities of hydrolases (β-glucosidase, cellobiohydrolase, β-N-acetylglucosaminidase and acid phosphatase), with those parameters all being highest at 20 °C in meadows and showing various dynamics in wetlands. Soil DOM in wetlands presented the lowest values of specific ultraviolet absorbances (SUVA₂₅₄ and SUVA₂₆₀) at 0 °C and the highest values at 10 °C, whereas the opposite was true in the meadows. Wetland soils had greater diversities of DOM molecular compositions and microbial communities, with warming gradually increasing the number of identified DOM compounds in meadows and decreasing the number of microbial species in both soils. Wetland soils had more Proteobacteria (44.2%) and Acidobacteria (21.1%) and fewer Actinobacteria (18.0%) than meadow soils and contained many temperature-sensitive archaea (which were abundant at 0 °C). Distance-based redundancy analysis and Procrustes analysis indicated the greater complexity of ecological responses in alpine wetlands, which may be attributed to the higher adaptive capacity of soil microbial communities. Our results suggest that both degradation and warming decrease soil DOM content and microbial activities in alpine wetlands, providing important references for alpine wetland conservation under current climate change.

作为重要的碳汇，青藏高原高山湿地正在经历严重的退化。为了揭示高山环境中变暖引起的生态变化，本研究测定了土壤养分含量、酶活性、吸收和荧光光谱以及溶解有机物（DOM）和宏基因组的四极飞行时间质谱（代谢组）。高山湿地和草甸（退化湿地）表土的长期培养（0°C、10°C 和 20°C）。与草甸相比，湿地土壤DOM（溶解性有机碳、溶解性有机氮、溶解性磷）含量较高，水解酶（β-葡萄糖苷酶、纤维二糖水解酶、β-N-乙酰氨基葡萄糖苷酶、酸性磷酸酶）活性较高，这些参数均为草地最高温度为 20 °C，湿地表现出各种动态。湿地土壤 DOM 在 0 °C 时呈现最低的特定紫外吸光度值（SUVA ₂₅₄和 SUVA ₂₆₀ ），在 10 °C 时呈现最高值，而草甸中则相反。湿地土壤的 DOM 分子组成和微生物群落具有更大的多样性，随着变暖，草地中已识别的 DOM 化合物的数量逐渐增加，而两种土壤中微生物物种的数量逐渐减少。与草甸土壤相比，湿地土壤的变形菌门（44.2%）和酸杆菌门（21.1%）较多，放线菌门（18.0%）较少，并且含有许多对温度敏感的古菌（在0°C时含量丰富）。基于距离的冗余分析和Procrustes分析表明高寒湿地生态响应更加复杂，这可能归因于土壤微生物群落的较高适应能力。 研究结果表明，退化和变暖都会降低高寒湿地土壤DOM含量和微生物活性，为当前气候变化下高寒湿地保护提供重要参考。