This study aimed to understand the role of the phytoplankton species-specific associated bacteria in the phytoplankton taxon-dependant oil response. In this context, 3 different phytoplankton species (Amphidinium carterae, Peridinium sociale and Skeletonema sp.) were exposed to dispersant alone, dispersed and undispersed crude oil. During the experiment, phytoplankton physiology was followed as well as the phytoplankton-attached and free-living bacteria activities and community structures