Archaeal Community and Function Disturbed Significantly in Surrounding Soil by Coal Gangue Stockpiling

Coal gangue (CG) dumped in open-air piles significantly impacts the surrounding soil environment. To investigate the effects of prolonged CG dumping on soil archaeal communities and their ecological functions, we used metagenomic sequencing to analyze soil samples, including control soil area not impacted by CG (CSL), undisturbed control sediment (CST), atmospheric dust fall area (ADF), and leachate flow area (LFA) samples. The results showed that the dominant phylum and genus of archaea were Thaumarchaeota (30.53–93.39%) and Candidatus Nitrosocosmicus (34.44–69.85%) in the different samples. Significant differences were observed in both α- and β-diversity (p < 0.05); archaeal community composition was primarily influenced by total nitrogen (TN), electrical conductivity (EC), Cu, As, and Cd. The contribution rate of As was the largest, about 44.8%. The metabolic functions of archaea were predominantly related to amino acid metabolism, and there were significant variations in carbon and nitrogen metabolic pathways in different areas. The ppdk gene showed considerable variation between ADF and CSL, and Euryarchaeota was the major contributing phylum to carbon fixation. However, for nitrogen metabolism, the gltB gene displayed marked differences, and the phylum of Thaumarchaeota was the major contributor. This study provides a theoretical foundation for land management and sustainable utilization in CG dump areas.