Arsenic pollution from human activities drives changes in soil microbial community characteristics.

Soil arsenic (As) pollution not only decreases plant productivity but also soil quality, in turn hampering sustainable agricultural development. Despite the negative effects of As contamination on rice yield and quality being reported widely, the responses of microbial communities and co-occurrence networks in paddy soil to As pollution have not been explored. Here, based on high-throughput sequencing technologies, we investigated bacterial abundance and diversity in paddy soils with different levels of As contamination, and constructed associated microbial co-occurrence networks. As pollution reduced soil bacterial diversity significantly (p < 0.001). In addition, bioavailable As concentrations were negatively correlated with Actinobacteria and Acidobacteria relative abundance (p < 0.05). Conversely, As pollution had a positive relationship with Chloroflexi, Betaproteobacteria, and Bacteroidetes relative abundance (p < 0.05). Firmicutes relative abundance decreased with an increase in total As concentration. The ecological clusters and key groups in bacterial co-occurrence networks exhibited distinct trends with an increase in As pollution. Notably, Acidobacteria play an important role in maintaining microbial networks in As contaminated soils. Overall, we provide empirical evidence that As contamination influences soil microbial community structure, posing a threat to soil ecosystem health and sustainable agriculture.