ABSTRACT
The maintaining mechanism of community diversity is the core of community ecology. The mine tailing is a good field for studying on the underlying mechanism of community diversity, as a kind of original bare land with heavy metal pollution, where the physicochemical characteristics of soil change with the restoration periods. We examined the driving forces for bacterial community diversity based on the investigation of edaphic factors, plant community, and bacterial communities in Shibahe copper mine tailing, Shanxi. The results showed that nutrient contents in soil increased with restoration periods. The seasonal dynamics of soil nutrient in different restoration time were different. Shannon diversity and richness of bacterial community showed an increasing trend, indicating community stability was improved with restoration. Influenced by plant community, the seasonal changes of those indices differed with restoration. Results from the RDA analysis showed that the diversity and structure of bacterial communities were determined by environmental factors (edaphic, plant and heavy metals). Results from the structure equation models further confirmed that soil nutrients (TC, TN, NO3--N, NO2-N), plant community, and soil enzyme activities jointly drove bacterial community assembly on the copper mine tailings.
Subject(s)
Copper , Soil Microbiology , Soil Pollutants , China , Mining , SoilABSTRACT
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 MiSeq 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.
Subject(s)
Copper , Microbial Consortia , Mining , Soil Microbiology , Bacteria/classification , Fungi/classification , SoilABSTRACT
In order to reveal the effects of heavy metal pollution on microbial community compositions and microbial community diversity in tailing area,we conducted an experiment by examining the microbial community in tailing water,sediments and tailing sand in Shibahe copper tailing in Zhongtiao Mountain.Differences in microbial community compositions in different habitats and their relationships with environmental parameters were analyzed.The results showed that the richness and diversity of microbial community were the largest in tailing sand,but the lowest in tailing water.Microbial community compositions were similar between tailing water and sediments.There were significant positive correlations between the relative abundance of the dominant family (Sphingomonadaceae) and contents of heavy metals (Cd,Cu,Mn,Ni,Pb,Zn),while there were significant negative correlations between relative abundances of aulobacteraceae, Methylobacteriaceae, Nocardioidaceae, Microbacteriaceae, Micrococcaceae, Streptococcaceae and Paenibacillaceae and heavy metal contents.It showed that most of the bacteria were inhibited by heavy metals,but Sphingomonadaceae had a higher tolerance to heavy metals which may indicate that it has a potential for remediation of heavy metal contamination.