Soil microorganisms enrichment in different rare earth elements enrichment soils around a rare earth tailings pond.

Soil microorganisms respond vigorously to environmental changes. However, the impact of varying levels of rare earth elements (REEs) contamination on microorganisms and their interactions remains unclear, with a scarcity of research on biomarkers for different levels of rare earth enrichment. This study categorized REE concentrations into distinct accumulation tiers. Utilizing Illumina high-throughput sequencing, the researchers investigated how different REE levels affect biodiversity, ecosystem structure, and functional dynamics. The results indicated that while the accumulation of rare earth elements (REEs) reduced soil bacterial diversity, the impact on the diversity of bacterial populations was minimal. Proteobacteria, Actinobacteria, and Chloroflexi were identified as the dominant bacterial communities near the uncommon rare earth tailings pond. According to linear discriminant analysis effect size (LEfSe), certain genera-Halomonas, Aliifodinibius, and Truepera-emerged as potential indicators of soils with elevated REE concentrations. Sphingomonas was identified as the biomarker in medium-concentration (MC) samples, whereas norank_Subgroup6, norank_Actinobacteria, and RB41 were enriched in low-concentration (LC) samples. Tax4fun function prediction revealed that the metabolic capacity of bacterial communities was inhibited under REE stress. Statistical analyses, including redundancy analysis and the Mantel test, pinpointed soil moisture and rare earth element concentrations as the primary environmental drivers in mining-affected regions. These findings illustrate that rare earth accumulation significantly alters bacterial community diversity, taxonomic composition, and ecological functions in these areas. Researchers also identified distinct microbial biomarkers corresponding to various levels of rare earth enrichment. The study offers deeper insights into how rare earth mining operations affect the composition and function of soil microbial communities.