Bacterial community dynamics underlie ecosystem functioning in river networks, yet how different bacterial lifestyles respond to bottom-up biotic drivers under confluence-induced hydraulics remains unclear. Here, we quantified spatial heterogeneity in free-living (FL), particle-associated (PA) and sedimentary (S) bacterial assemblages, coupled with phytoplankton and extracellular enzyme profiles, at the Yellow River-Fenhe River confluence during the summer wet season. Clear habitat partitioning