Free-living bacterial communities associated to a coastal tidal front

Ocean Frontal systems are complex hydrological features of high biological importance. The well-studied Ushant front represents the prominent structure in the Iroise sea (West Britanny, France) in summer. It is a tidal front that delimits two bodies of water: stratified offshore and vertically mixed inshore waters, with very contrasted nutrients and light availability for microorganisms. Ecological structure of the front has been quite well described for eukaryotic plankton. However, the large diversity of marine Bacteria hasn't been investigated despite the central role of these microorganisms involved in primary and secondary production, in biogeochemical cycles and engaged in close interactions with eukaryotic plankton. In this study we investigated the community dynamics of free-living bacteria in the Iroise Sea, during four cruises in September 2014, March 2015, July 2015 and September 2015, five stations, and three depth, depending on the stratification. Bacterial communities were investigated using 16S rRNA amplicon (v4-v5 regions)