Transitions in bacterial communities along the 2000 km salinity gradient of the Baltic Sea

摘要: Salinity is a major factor controlling the distribution of biota in aquatic systems, and most multicellular organisms are either adapted to life saltwater or freshwater conditions. Consequently, saltwater–freshwater mixing zones coastal estuarine areas characterized by limited faunal floral diversity. Although changes diversity decline species richness brackish waters well documented ecology, it unknown what extent this applies bacterial communities. Here, we report first detailed inventory from vertical profiles 60 sampling stations distributed along salinity gradient Baltic Sea, one world's largest water environments, generated using 454 pyrosequencing partial (400 bp) 16S rRNA genes. Within gradient, community composition altered at broad finer-scale phylogenetic levels. Analogous communities within conditions, identified comprising diverse combination marine groups, with populations unique environment. As residence times Sea exceed 3 years, observed cannot be result fresh saltwater, but our study represents description an autochthonous microbiome. In contrast organisms, reduced conditions could not established. It possible that rapid adaptation rate bacteria has enabled variety lineages fill for higher remains challenging relatively unoccupied ecological niche.