Short-term warming decreased soil DOM content and microbial species in alpine wetlands but increased soil DOM content and hydrolase activity in alpine meadows on the Tibetan Plateau
Shiyu Fan, Jihong Qin, Hui Sun, Zhenchu Dan, Wenqing Chen, Jiyuan Yang
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引用次数: 0
Abstract
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.
短期变暖降低了高山湿地的土壤 DOM 含量和微生物种类,但增加了青藏高原高山草甸的土壤 DOM 含量和水解酶活性
作为重要的碳汇,青藏高原的高寒湿地正在经历严重退化。为了揭示气候变暖引起的高寒环境生态变化,本研究对高寒湿地和草甸(退化湿地)的表土进行了短期培养(0 °C、10 °C和20 °C),测定了土壤养分含量、酶活性、吸收和荧光光谱以及四极飞行时间质谱(代谢组)中溶解有机物(DOM)和元基因组的含量。与草甸相比,湿地的土壤 DOM(溶解有机碳、溶解有机氮和溶解磷)含量更高,水解酶(β-葡萄糖苷酶、纤维生物水解酶、β-N-乙酰葡萄糖苷酶和酸性磷酸酶)的活性也更高,草甸的这些参数在 20 °C 时最高,而湿地的这些参数则呈现出不同的动态变化。湿地土壤 DOM 的特定紫外线吸收率(SUVA254 和 SUVA260)在 0 °C 时最低,在 10 °C 时最高,而草地则相反。湿地土壤中 DOM 分子组成和微生物群落的多样性更高,草甸土壤中确定的 DOM 化合物的数量随着气候变暖而逐渐增加,而两种土壤中微生物物种的数量则逐渐减少。与草甸土壤相比,湿地土壤中的蛋白质细菌(44.2%)和酸性细菌(21.1%)较多,放线菌(18.0%)较少,并且含有许多对温度敏感的古细菌(在 0 °C 时含量丰富)。基于距离的冗余分析和 Procrustes 分析表明,高山湿地的生态响应更为复杂,这可能是因为土壤微生物群落的适应能力更强。我们的研究结果表明,退化和变暖都会降低高山湿地的土壤DOM含量和微生物活动,这为当前气候变化下的高山湿地保护提供了重要参考。
期刊介绍:
Biogeochemistry publishes original and synthetic papers dealing with biotic controls on the chemistry of the environment, or with the geochemical control of the structure and function of ecosystems. Cycles are considered, either of individual elements or of specific classes of natural or anthropogenic compounds in ecosystems. Particular emphasis is given to coupled interactions of element cycles. The journal spans from the molecular to global scales to elucidate the mechanisms driving patterns in biogeochemical cycles through space and time. Studies on both natural and artificial ecosystems are published when they contribute to a general understanding of biogeochemistry.