title: Short-term dynamics of bacterial communities in a tidally affected coastal ecosystem.
abstract: Tidal effects on the composition of free-living (FL) and particle-associated (PA) bacterial communities were studied in a tidal flat ecosystem in the southern North Sea. Denaturing gradient gel electrophoresis targeting the 16S rRNA gene and the 16S rRNA of Bacteria, Bacteroidetes, Alphaproteobacteria and the Roseobacter clade was applied. Despite strong tidal variations in the quantity and, depending on the season, also the quality of suspended matter as well as variations in bacterial activity, the bacterial community composition remained rather stable. FISH showed some variations of the community composition, but these were not related to typical tidal situations. Variations were higher during tidal cycles in May and July compared with November. Bacteroidetes, Alpha- and Gammaproteobacteria constituted the majority of the bacterial communities but relative proportions of the different groups varied considerably. On particles, Betaproteobacteria were also detected to substantial proportions. The Roseobacter clade constituted up to 90% of FL but only 30% of PA Alphaproteobacteria. Banding patterns of the Bacteroidetes-specific amplicons, and in particular those targeting the 16S rRNA, revealed tidally induced effects, as several bands appeared or disappeared at distinct events such as slack water or resuspension. Sequencing of prominent bands revealed predominantly phylotypes reported previously from this ecosystem.
authors.affiliation: Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg, Oldenburg, Germany.
authors.forename: Beate
authors.initials: B
authors.lastname: Rink
authors.forename: Torben
authors.initials: T
authors.lastname: Martens
authors.forename: Doreen
authors.initials: D
authors.lastname: Fischer
authors.forename: Andreas
authors.initials: A
authors.lastname: Lemke
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Grossart
authors.forename: Meinhard
authors.initials: M
authors.lastname: Simon
authors.forename: Thorsten
authors.initials: T
authors.lastname: Brinkhoff
mesh_terms: D039903:Actinobacteria / Q000145:classification / Q000235:genetics / Q000254:growth & development; D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000254:growth & development*; D041963:Bacteroidetes / Q000145:classification / Q000235:genetics / Q000254:growth & development; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000032:analysis / Q000302:isolation & purification; D017753:Ecosystem; D004587:Electrophoresis, Agar Gel; D017404:In Situ Hybridization, Fluorescence; D008969:Molecular Sequence Data; D052638:Particulate Matter; D020560:Proteobacteria / Q000145:classification / Q000235:genetics / Q000254:growth & development; D012621:Seasons; D012623:Seawater / Q000382:microbiology*; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D052638:Particulate Matter