Originality-Significance Statement 22This study establishes, for the first time, CSR life-history strategies in the context of bacterial 23 communities. This framework is explained using community aggregated traits in an environment other 24 than soil, also a first, using a combination of ordination methods, network analysis, and genotypic 25 information from shotgun metagenomics and 16S rRNA gene amplicon sequencing. 26
Summary 27Trait-based approaches are increasingly gaining importance in community ecology, as a way of finding 28 general rules for the mechanisms driving changes in community structure and function under the 29 influence of perturbations. Frameworks for life-history strategies have been successfully applied to 30 describe changes in plant and animal communities upon disturbance. To evaluate their applicability to 31 complex bacterial communities, we operated replicated wastewater treatment bioreactors for 35 days 32 and subjected them to eight different disturbance frequencies of a toxic pollutant (3-chloroaniline), 33 starting with a mixed inoculum from a full-scale treatment plant. Relevant ecosystem functions were 34 tracked and microbial communities assessed through metagenomics and 16S rRNA gene sequencing. 35Combining a series of ordination, statistical and network analysis methods, we associated different life-36 history strategies with microbial communities across the disturbance range. These strategies were 37 evaluated using tradeoffs in community function and genotypic potential, and changes in bacterial genus 38 composition. We further compared our findings with other ecological studies and adopted a semi-39 quantitative CSR (competitors, ruderals, stress-tolerants) classification. The framework reduces 40 complex datasets of microbial traits, functions, and taxa into ecologically meaningful components to 41 help understand the system response to disturbance, and hence represents a promising tool for managing 42 microbial communities. 43