title: Metagenome-assembled genomes uncover a global brackish microbiome.
abstract: BACKGROUND
  Microbes are main drivers of biogeochemical cycles in oceans and lakes. Although the genome is a foundation for understanding the metabolism, ecology and evolution of an organism, few bacterioplankton genomes have been sequenced, partly due to difficulties in cultivating them.
  
  
  RESULTS
  We use automatic binning to reconstruct a large number of bacterioplankton genomes from a metagenomic time-series from the Baltic Sea, one of world's largest brackish water bodies. These genomes represent novel species within typical freshwater and marine clades, including clades not previously sequenced. The genomes' seasonal dynamics follow phylogenetic patterns, but with fine-grained lineage-specific variations, reflected in gene-content. Signs of streamlining are evident in most genomes, and estimated genome sizes correlate with abundance variation across filter size fractions. Comparing the genomes with globally distributed metagenomes reveals significant fragment recruitment at high sequence identity from brackish waters in North America, but little from lakes or oceans. This suggests the existence of a global brackish metacommunity whose populations diverged from freshwater and marine relatives over 100,000 years ago, long before the Baltic Sea was formed (8000 years ago). This markedly contrasts to most Baltic Sea multicellular organisms, which are locally adapted populations of freshwater or marine counterparts.
  
  
  CONCLUSIONS
  We describe the gene content, temporal dynamics and biogeography of a large set of new bacterioplankton genomes assembled from metagenomes. We propose that brackish environments exert such strong selection that lineages adapted to them flourish globally with limited influence from surrounding aquatic communities.
authors.affiliation: KTH Royal Institute of Technology, Science for Life Laboratory, School of Biotechnology, Division of Gene Technology, Stockholm, Sweden. luisa.hugerth@scilifelab.se.
authors.forename: Luisa W
authors.initials: LW
authors.lastname: Hugerth
authors.affiliation: Centre for Ecology and Evolution in Microbial model Systems - EEMiS, Linnaeus University, Barlastgatan 11, SE-39182, Kalmar, Sweden. john.larsson@scilifelab.se.
authors.forename: John
authors.initials: J
authors.lastname: Larsson
authors.affiliation: KTH Royal Institute of Technology, Science for Life Laboratory, School of Biotechnology, Division of Gene Technology, Stockholm, Sweden. johannes.alneberg@scilifelab.se.
authors.forename: Johannes
authors.initials: J
authors.lastname: Alneberg
authors.affiliation: Centre for Ecology and Evolution in Microbial model Systems - EEMiS, Linnaeus University, Barlastgatan 11, SE-39182, Kalmar, Sweden. markusvlindh@gmail.com.
authors.forename: Markus V
authors.initials: MV
authors.lastname: Lindh
authors.affiliation: Centre for Ecology and Evolution in Microbial model Systems - EEMiS, Linnaeus University, Barlastgatan 11, SE-39182, Kalmar, Sweden. catherine.legrand@lnu.se.
authors.forename: Catherine
authors.initials: C
authors.lastname: Legrand
authors.affiliation: Centre for Ecology and Evolution in Microbial model Systems - EEMiS, Linnaeus University, Barlastgatan 11, SE-39182, Kalmar, Sweden. jarone.pinhassi@lnu.se.
authors.forename: Jarone
authors.initials: J
authors.lastname: Pinhassi
authors.affiliation: KTH Royal Institute of Technology, Science for Life Laboratory, School of Biotechnology, Division of Gene Technology, Stockholm, Sweden. anders.andersson@scilifelab.se.
authors.forename: Anders F
authors.initials: AF
authors.lastname: Andersson
mesh_terms: D001419:Bacteria / Q000235:genetics; D016680:Genome, Bacterial; D054892:Metagenome; D064307:Microbiota / Q000235:genetics*; D009792:Oceans and Seas; D010802:Phylogeny; D058974:Phylogeography; D010933:Plankton / Q000235:genetics*; D012621:Seasons; D012623:Seawater / Q000382:microbiology*