title: Bacterioplankton Biogeography of the Atlantic Ocean: A Case Study of the Distance-Decay Relationship.
abstract: In order to determine the influence of geographical distance, depth, and Longhurstian province on bacterial community composition and compare it with the composition of photosynthetic micro-eukaryote communities, 382 samples from a depth-resolved latitudinal transect (51°S-47°N) from the epipelagic zone of the Atlantic ocean were analyzed by Illumina amplicon sequencing. In the upper 100 m of the ocean, community similarity decreased toward the equator for 6000 km, but subsequently increased again, reaching similarity values of 40-60% for samples that were separated by ~12,000 km, resulting in a U-shaped distance-decay curve. We conclude that adaptation to local conditions can override the linear distance-decay relationship in the upper epipelagial of the Atlantic Ocean which is apparently not restrained by barriers to dispersal, since the same taxa were shared between the most distant communities. The six Longhurstian provinces covered by the transect were comprised of distinct microbial communities; ~30% of variation in community composition could be explained by province. Bacterial communities belonging to the deeper layer of the epipelagic zone (140-200 m) lacked a distance-decay relationship altogether and showed little provincialism. Interestingly, those biogeographical patterns were consistently found for bacteria from three different size fractions of the plankton with different taxonomic composition, indicating conserved underlying mechanisms. Analysis of the chloroplast 16S rRNA gene sequences revealed that phytoplankton composition was strongly correlated with both free-living and particle associated bacterial community composition (R between 0.51 and 0.62, p < 0.002). The data show that biogeographical patterns commonly found in macroecology do not hold for marine bacterioplankton, most likely because dispersal and evolution occur at drastically different rates in bacteria.
authors.affiliation: Group Microbial Communication, Helmholtz-Center for Infection Research Braunschweig, Germany.
authors.forename: Mathias
authors.initials: M
authors.lastname: Milici
authors.affiliation: Group Microbial Communication, Helmholtz-Center for Infection Research Braunschweig, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Tomasch
authors.affiliation: Group Microbial Interactions and Processes, Helmholtz-Center for Infection Research Braunschweig, Germany.
authors.forename: Melissa L
authors.initials: ML
authors.lastname: Wos-Oxley
authors.affiliation: UMR 7144 - Sorbonne Universités, UPMC Univ Paris 06, Station Biologique de RoscoffRoscoff, France; Centre National de la Recherche Scientifique, UMR 7144, Station Biologique de RoscoffRoscoff, France.
authors.forename: Johan
authors.initials: J
authors.lastname: Decelle
authors.affiliation: Group Microbial Interactions and Processes, Helmholtz-Center for Infection Research Braunschweig, Germany.
authors.forename: Ruy
authors.initials: R
authors.lastname: Jáuregui
authors.affiliation: Group Microbial Communication, Helmholtz-Center for Infection Research Braunschweig, Germany.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.affiliation: Group Microbial Communication, Helmholtz-Center for Infection Research Braunschweig, Germany.
authors.forename: Zhi-Luo
authors.initials: ZL
authors.lastname: Deng
authors.affiliation: Group Microbial Interactions and Processes, Helmholtz-Center for Infection Research Braunschweig, Germany.
authors.forename: Iris
authors.initials: I
authors.lastname: Plumeier
authors.affiliation: Department of Biology of Geological Processes, Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg Oldenburg, Germany.
authors.forename: Helge-Ansgar
authors.initials: HA
authors.lastname: Giebel
authors.affiliation: Department of Biology of Geological Processes, Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg Oldenburg, Germany.
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Badewien
authors.affiliation: Department of Biology of Geological Processes, Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg Oldenburg, Germany.
authors.forename: Mascha
authors.initials: M
authors.lastname: Wurst
authors.affiliation: Department of Biology of Geological Processes, Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg Oldenburg, Germany.
authors.forename: Dietmar H
authors.initials: DH
authors.lastname: Pieper
authors.affiliation: Department of Biology of Geological Processes, Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg Oldenburg, Germany.
authors.forename: Meinhard
authors.initials: M
authors.lastname: Simon
authors.affiliation: Group Microbial Communication, Helmholtz-Center for Infection Research Braunschweig, Germany.
authors.forename: Irene
authors.initials: I
authors.lastname: Wagner-Döbler
keywords: Particle associated bacteria; bacterioplankton; biogeography; distance-decay relationship; macroecology; marine bacteria; microalgae; oceanographic province