Relationships between microbial characteristics and the arsenic cycle in high-arsenic groundwater

Abstract Microbial activities play a pivotal role in the migration and transformation of arsenic (As) within groundwater systems, particularly at high concentrations. Focusing on the Kuitun River Basin, this study used high-throughput sequencing to unravel the intricate diversity of microbial communities and their influence on As enrichment. Groundwater with elevated As hosted richer and more diverse microbial populations compared to that with lower As levels. The Sobs and Shannon diversity indices for the high-As group initially declined before rising with increasing As concentrations. Key microbial taxa dominating these ecosystems included Pseudomonas , Acinetobacter , Aquabacterium , Novosphingobium , and Sphingobium , with Pseudomonas showing substantial variation in abundance across different As concentrations. Distance-based redundancy analysis emphasized the importance of dissolved oxygen in shaping the microbial landscape, followed closely by the interplay between iron and As concentrations. Flavobacteriaceae and Burkholderiaceae displayed inverse correlations with As levels, highlighting the multifaceted relationship between microbial communities and groundwater chemistry. This investigation underscores the profound impact of As concentration gradients on microbial biodiversity and elucidates a complex regulatory framework where environmental parameters and microorganisms collaborate in governing As accumulation in groundwater. The results enrich our understanding of the biogeochemical dynamics underlying arsenic behavior in subterranean aquatic habitats.