Single diatom like particles Metagenome. freshwater metagenome

Bacterial colonization of living and dead particles is central to the functioning of freshwater ecosystems. While studies on such colonization are typically based on bulk analysis, only a few have tried to reveal interactions and population linkages at the biologically relevant scale of individual particles. We used next generation sequencing of the bacterial 16SrRNA gene to characterize bacterial communities attached to individual diatom cells and other particles of similar size (phytoplankton and macrophyte debris) in Lake Erken, Sweden. We compared the diatom-attached communities with the reported typical freshwater community, and used co-occurrence network analysis to uncover intrapopulation interactions on the microscopic particles and linkages between specific diatoms and the associated bacterial communities. Our study demonstrates that bacterial communities attached to the particles differ strongly in composition as compared to the typical free-living bacterioplankton and further demonstrate that the composition of bacterial communities colonizing individual phytoplankton cells are not shaped by the specific diatom species. Instead, the data suggest that associations and dependencies within the colonizing community determine their respective composition.