铜尾矿库坝面土壤微生物群落动态的驱动因子

Driving Factors of the Dynamics of Microbial Community in a Dam of Copper Mine Tailings

随机过程和确定性过程对群落动态的影响机制及重要性是群落生态学研究的中心课题,也是目前群落生态学最具争议的问题.微生物群落在生态系统物质循环和能量流动过程中发挥着重要作用,对其结构动态的研究不仅为阐明群落构建机制提供重要的数据支持,而且为预测环境胁迫条件下微生物群落结构的动态提供理论依据.本研究通过Illumina Mi Seq测序的方法,分析了中条山十八河尾矿库坝面不同恢复阶段细菌和真菌群落结构特征.结果表明,研究区尾矿坝不同恢复年限土壤理化性质发生梯度变化,植物群落结构呈现一定的演替趋势,植物群落多样性与土壤养分显著相关,而与土壤重金属含量无相关性.不同恢复年限的土壤微生物群落结构具有显著差异,其中优势细菌主要有变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、厚壁菌门(Firmicutes)、酸杆菌门(Acidobacteria);优势真菌主要有子囊菌门(Ascomycota)、担子菌门(Basidiomycota)、接合菌门(Zygomycota).微生物群落组成主要受到土壤养分和重金属含量的影响,而植物多样性对微生物群落结构的影响不明显,表明在局域小尺度环境胁迫条件下,土壤环境因子是微生物群落结构动态变化的主要驱动力.

The relative importance of the deterministic versus stochastic processes underlying community dynamics has long been a central theme in community ecology,and is intensively debated in the field. Microbial communities play key roles in nutrient cycling and the flow of energy in ecosystems. The research on the structural dynamics of microbial community will provide data and theoretical support for understanding the assembly mechanisms of community,and for predicting the dynamics of microbial community under environmental stress. In this study,the Illumina Mi Seq method was applied to investigate the structural dynamics of bacterial and fungal community in a dam of Shibahe mine tailings at different restoration stages（ 1-45 years）. The results indicated that the soil physicochemical properties in the dam of mine tailings formed an ecological gradient,and the plant community showed succession along the restoration time. The diversity of plant communities was significantly correlated with soil nutrient contents but not with soil heavy metal contents. The structure of the microbial communities showed significant differences at different restoration stages of the dam land,in which Proteobacteria, Actinobacteria, Firmicutes, and Acidobacteria were the dominant bacterial phyla, and Ascomycota,Basidiomycota,and Zygomycota were the dominant fungal phyla. The assembly of the microbial community was shaped mainly by the soil nutrients and soil heavy metal contents,but plant diversity had no significant effect on the microbial community structure. It was suggested that edaphic factors drive the dynamics of microbial communities under the stress conditions of pH and heavy metals on small,local scales.