Soil Microbial Communities in Desert Grassland around Rare Earth Mine: Diversity, Variation, and Response Patterns

Abstract

Bayan Obo mine is so far the world’s largest rare earth mine. Critical concerns arise as (1) whether there is an accumulation of exogenous rare earth elements (REE) in the desert steppe on the periphery of the mine and (2) how the exogenous rare earth accumulation affects the soil microbial communities nearby. In this study, nine sample sites were set up according to their distance gradients from the mine. Illumina high-throughput sequencing targeting 16S rRNA genes were conducted. The results show that the accumulation of exogenous rare earth in the desert at the periphery of the Bayan Obo mine vary at distance gradients. Fortunately, no significant effects on the physicochemical properties of the soil were found. However, the composition of the soil microbial community changed significantly in response to the variation in distance gradient. Highly abundant microbial genera YC-ZSS-LKJ147, Subgroup_10, and Sphingomonas were positively correlated with REE, whereas Pseudomonas is negative correlated. Total phosphorus (TP) was attributed to 5.95% of the variation in microbial communities, followed by light rare earth elements (LREE, 5.39%). The study provides evidence for the ecological risks posed to soil ecosystems by the long-term accumulation of exogenous REE in the Bayan Obo mine.