Multiple stressor effects on stream benthic bacteria

Disentangling the individual and interactive effects of multiple stressors on microbial communities is a key challenge to our understanding and management of ecosystems. Recent advances in molecular techniques allow studying microbial communities in situ, with high taxonomic resolution. However, it remains unknown which taxonomic level provides the best trade-off between maximising our ability to detect and interpret multiple-stressor effects versus the goal of studying the entire bacterial community. We used 64 outdoor mesocosms (simulating small streams) to investigate effects of four agricultural stressors (nutrient enrichment, the nitrification inhibitor DCD, fine sediment and flow velocity reduction) on stream bacteria at phylum, order, genus and OTU levels. Community composition was assessed using amplicon sequencing (16S rRNA gene, V3-V4 region).