Exploitation alters microbial community and its co-occurrence patterns in ionic rare earth mining sites

Area of Science:

• Environmental microbiology
• Soil science
• Ecology

Background:

• Rare earth element (REE) mining causes significant environmental issues.
• The impact of REE mining on soil prokaryotic communities and their interactions is not well understood.

Purpose of the Study:

• To investigate the effects of REE mining on bacterial, archaeal, and ammonia-oxidizing communities.
• To analyze the interactions within these microbial communities in mining-affected soils.

Main Methods:

• High-throughput sequencing and quantitative polymerase chain reaction (qPCR) were used.
• Microbial community structure, abundance, and co-occurrence networks were analyzed.
• Soil properties including nutrients and total rare earth elements (TREEs) were assessed.

Main Results:

• Mining soils showed poor structure, nutrient deficiency, and high REEs.
• Oligotrophic bacteria dominated mining and unexploited soils, while copiotrophic bacteria were abundant in surrounding soils.
• Archaea were more stable than bacteria, with ammonia-oxidizing archaea (AOA) outnumbering ammonia-oxidizing bacteria (AOB) and being influenced by pH, nutrients, and TREEs.
• Mining decreased microbial network complexity and stability, with oligotrophic Chloroflexi replacing copiotrophic Proteobacteria and Actinobacteriota as key taxa.

Conclusions:

• REE mining significantly alters soil microbial community structure and function.
• Exploitation leads to less stable microbial ecosystems and shifts in key taxa.
• Findings are vital for ecological risk assessment of REE mining operations.