title: Bacterial Diversity in Ships' Ballast Water, Ballast-Water Exchange, and Implications for Ship-Mediated Dispersal of Microorganisms.
abstract: Using next-generation DNA sequencing of the 16S rRNA gene, we analyzed the composition and diversity of bacterial assemblages in ballast water from tanks of 17 commercial ships arriving to Hampton Roads, Virginia (USA) following voyages in the North Atlantic Ocean. Amplicon sequencing analysis showed the heterogeneous assemblages were (1) dominated by Alpha- and Gammaproteobacteria, Bacteroidetes, and unclassified Bacteria; (2) temporally distinct (June vs August/September); and (3) highly fidelitous among replicate samples. Whether tanks were exchanged at sea or not, their bacterial assemblages differed from those of local, coastal water. Compositional data suggested at-sea exchange did not fully flush coastal Bacteria from all tanks; there were several instances of a genetic geographic signal. Quantitative PCR yielded no Escherichia coli and few instances of Vibrio species. Salinity, but not ballast-water age or temperature, contributed significantly to bacterial diversity. Whether anthropogenic mixing of marine Bacteria restructures their biogeography remains to be tested.
authors.affiliation: Department of Plant and Microbial Biology, University of California-Berkeley , 331 Koshland Hall, Berkeley, California 94720, United States.
authors.forename: Despoina S
authors.initials: DS
authors.lastname: Lymperopoulou
authors.affiliation: Department of Ocean, Earth and Atmospheric Sciences, Old Dominion University , 4600 Elkhorn Avenue, Norfolk, Virginia 23529, United States.
authors.forename: Fred C
authors.identifier: 0000-0002-3901-179X
authors.initials: FC
authors.lastname: Dobbs
mesh_terms: D012336:RNA, Ribosomal, 16S; D012623:Seawater / Q000382:microbiology*; D012767:Ships; D014733:Vibrio; D014867:Water
chemical_list: D012336:RNA, Ribosomal, 16S; D014867:Water