The Zoige alpine wetland is one of the most sensitive ecosystems to global climate change. It is the largest alpine wetland in the world and currently suffers from serious drought and degradation. In this study, soil microbial communities of five soils with different moisture content were investigated by Illumina MiSeq high-throughput sequencing of 16S rRNA. The results showed that soil acidity and the content of soil nutrients decreased with the decrease in soil moisture. The microbial richness indices (Chao1 and ACE) and diversity index (Shannon) were highest in the flooded wetland (FW) and lowest in the unflooded mound near the flooded wetland (UW). The relative abundance showed four dominated phyla among all the soil microbes in five soils: Proteobacteria (36.5%), Acidobacteria (26.1%), Actinobacteria (9.4%) and Bacteroidetes (5.8%). Moreover, Proteobacteria (51.4%) of UW was significantly (P < 0.05) higher than that of other soils, while Actinobacteria (1.6%), Gemmatimonadetes (0.9%) and Nitrospirae (0.03%) of UW were significantly (P < 0.05) lower than those of other soils. Principal component analysis (PCA) and redundancy analysis (RDA) revealed that soil samples of UW differed most from samples of other soils. Proteobacteria was positively correlated with water-soluble phosphorus, while Actinobacteria and Bacteroidetes were negatively correlated with total organic carbon and total nitrogen. Our findings revealed that soils in transitional unstable state from flooded to aridification had the lowest microbial diversity, and drought led to long-term changes in the microbial community in the Zoige wetland, which may cause further degradation of alpine wetland ecosystem functions.

Zoige高山湿地是全球气候变化最敏感的生态系统之一。它是世界上最大的高山湿地，目前遭受严重的干旱和退化。在这项研究中，通过Illumina MiSeq 16S rRNA高通量测序研究了五种水分含量不同的土壤的微生物群落。结果表明，土壤酸度和土壤养分含量随着土壤水分的减少而降低。淹没湿地（FW）的微生物丰富度指数（Chao1和ACE）和多样性指数（Shannon）最高，淹没湿地（UW）的未淹没土丘中最低。相对丰度显示在五个土壤中所有土壤微生物中有四个优势菌群：Proteobacteria（36.5％），Acidobacteria（26.1％），放线菌（9.4％）和拟杆菌（5.8％）。此外，变形菌（51.4％）UW的是显著（P  <0.05）高于其它污垢的较高，而放线菌（1.6％），芽单胞菌门（0.9％）和硝化螺旋菌门（0.03％）UW的均显著（P  <0.05）低于其他土壤。主成分分析（PCA）和冗余分析（RDA）显示，UW的土壤样品与其他土壤的样品差异最大。变形杆菌与水溶性磷呈正相关，而放线杆菌和拟杆菌属与总有机碳和总氮呈负相关。我们的发现表明，从淹没到干旱的过渡不稳定状态下的土壤微生物多样性最低，干旱导致Zoige湿地微生物群落的长期变化，这可能导致高山湿地生态系统功能进一步退化。