Abstract：
Acid mine drainage and sediments (AMD-Sed) contamination pose serious ecological and environmental problems. This study investigated the geochemical parameters and bacterial communities in the sediment layer (A) and buried soil layer (B) of desert grassland contaminated with AMD-Sed and compared them to an uncontaminated control soil layer (CK). The results showed that soil pH was significantly lower and iron, sulfur, and electroconductivity levels were significantly higher in the B layer compared to CK. A and B were dominated by Proteobacteria and Actinobacteriota, while CK was dominated by Firmicutes and Bacteroidota. The pH, Fe, S, and potentially toxic elements (PTEs) gradients were key influences on bacterial community variability, with AMD contamination characterization factors (pH, Fe, and S) explaining 48.6 % of bacterial community variation. A bacterial co-occurrence network analysis showed that AMD-Sed contamination significantly affected topological properties, reduced network complexity and stability, and increased the vulnerability of desert grassland soil ecosystems. In addition, AMD-Sed contamination reduced C/N-cycle functioning in B, but increased S-cycle functioning. The results highlight the effects of AMD-Sed contamination on soil bacterial communities and ecological functions in desert grassland and provide a reference basis for the management and restoration of desert grassland ecosystems in their later stages.
摘要：
酸性矿山排水和沉积物（AMD-Sed）污染带来了严重的生态和环境问题。本研究调查了受AMD-Sed污染的荒漠草原沉积层（A）和埋藏土层（B）的地球化学参数和细菌群落，并将其与未污染的对照土壤层（CK）进行了比较。结果表明,土壤pH值显著降低,铁,硫磺,与CK相比，B层中的电导率水平明显更高。A和B以变形杆菌和放线菌为主，而CK以Firmicutes和拟杆菌为主。pH值,Fe,S,潜在有毒元素（PTE）梯度是细菌群落变异的关键影响因素，与AMD污染表征因子(pH，Fe,和S）解释了48.6%的细菌群落变异。细菌共现网络分析显示，AMD-Sed污染显著影响拓扑特性，降低了网络的复杂性和稳定性，增加了荒漠草地土壤生态系统的脆弱性。此外,AMD-Sed污染减少了B的C/N循环功能，但增加了S循环功能。研究结果强调了AMD-Sed污染对荒漠草地土壤细菌群落和生态功能的影响,为荒漠草地生态系统后期的管理和恢复提供参考依据。
