Summary Open‐ocean convection is a fundamental process for thermohaline circulation and biogeochemical cycles that causes spectacular mixing of the water column. Here, we tested how much the depth‐stratified prokaryotic communities were influenced by such an event, and also by the following re‐stratification. The deep convection event (0–1500 m) that occurred in winter 2010–2011 in the NW Mediterranean Sea resulted in a homoge...