Abstract
More than twenty abandoned coal mines in the Yudong River basin of Guizhou Province have discharged acid mine drainage (AMD) for a long time. The revelation of microbial community composition, interaction patterns and metabolic functions can contributes to the ecological remediation of AMD pollution. In this study, reference and contaminated soils were collected along the AMD flow path for high-throughput sequencing. Results showed that the long-term AMD pollution promoted the evolution of γ-Proteobacteria, and the acidophilic iron-oxidizing bacteria Ferrovum (relative abundance of 15.50%) and iron-reducing bacteria Metallibacterium (9.87%) belonging to this class became the dominant genera. Co-occurrence analysis revealed that the proportion of positive correlations among bacteria increased from 51.02% (reference soil) to 75.16% (contaminated soil), suggesting that acidic pollution promotes the formation of mutualistic interaction networks of microorganisms. Metabolic function prediction (Tax4Fun) revealed that AMD contamination enhanced the microbial functions such as translation, repair, and biosynthesis of peptidoglycan and lipopolysaccharide etc., which may be an adaptive mechanism for microbial survival in extremely acidic environment. In addition, the acidic pollution promoted the high expression of nitrogen fixing genes in soil, and the discovery of autotrophic nitrogen fixing bacteria such as Ferrovum provided the possibility of bioremediation of AMD pollution.
Injection of FGD Grout to Abate Acid Mine Drainage in Underground Coal Mines