Search

Residual heavy metals in soils will destroy microbial community stability and influence its aggregation. However, exploring microbial ecology under heavy-metal stress still requires a conjoint analysis of bacterial interspecies communication and the community diversity maintenance mechanism. In this study, soil samples were collected from a heavy-metal-contaminated site in China to investigate the ecological response of indigenous microbial communities through high-throughput sequencing. Results showed that bacterial taxa and functions generated unusual decoupling phenomena. There were no significant differences in the diversity of species with the increase in concentration of heavy metals (Hg, Se, and Cr), but the functional diversity was lost. Also, the average niche breadth of bacterial species increased from 1.70 to 2.28, but community stability declined and the species assembly was always a deterministic process (NST <0.5). After the bacterial functional assembly changed from a stochastic process to a deterministic process (NST <0.5), it was transformed into a stochastic process (NST >0.5) again under the stress of high-concentration heavy metals, indicating that the collective stress resistance of bacterial communities changed from positive mutation into passive functional propagation. The research results can provide new insight into understanding the adaptive evolution of communities and ecosystem restoration under the stress of soil heavy metals. [Display omitted] • There is an unusual decoupling relation between taxa and functional diversity. • Microbial community stability decreased due to compound heavy metals exposure. • Deterministic process dominated the assemblies of bacterial taxa. • Bacterial resistance shifted from active to passive with increasing heavy metals. [ABSTRACT FROM AUTHOR]