title: Response of rare, common and abundant bacterioplankton to anthropogenic perturbations in a Mediterranean coastal site.
abstract: Bacterioplankton communities are made up of a small set of abundant taxa and a large number of low-abundant organisms (i.e. 'rare biosphere'). Despite the critical role played by bacteria in marine ecosystems, it remains unknown how this large diversity of organisms are affected by human-induced perturbations, or what controls the responsiveness of rare compared to abundant bacteria. We studied the response of a Mediterranean bacterioplankton community to two anthropogenic perturbations (i.e. nutrient enrichment and/or acidification) in two mesocosm experiments (in winter and summer). Nutrient enrichment increased the relative abundance of some operational taxonomic units (OTUs), e.g. Polaribacter, Tenacibaculum, Rhodobacteraceae and caused a relative decrease in others (e.g. Croceibacter). Interestingly, a synergistic effect of acidification and nutrient enrichment was observed on specific OTUs (e.g. SAR86). We analyzed the OTUs that became abundant at the end of the experiments and whether they belonged to the rare (<0.1% of relative abundance), the common (0.1-1.0% of relative abundance) or the abundant (>1% relative abundance) fractions. Most of the abundant OTUs at the end of the experiments were abundant, or at least common, in the original community of both experiments, suggesting that ecosystem alterations do not necessarily call for rare members to grow.
authors.affiliation: Centre for Ecology and Evolution in Microbial Model Systems, EEMiS, Linnaeus University, Barlastgatan 11, SE-391 82 Kalmar, Sweden Department of Marine Sciences, University of Otago, PO Box 56, Dunedin 9054, New Zealand federico.baltar@otago.ac.nz.
authors.forename: Federico
authors.initials: F
authors.lastname: Baltar
authors.affiliation: Centre for Ecology and Evolution in Microbial Model Systems, EEMiS, Linnaeus University, Barlastgatan 11, SE-391 82 Kalmar, Sweden.
authors.forename: Joakim
authors.initials: J
authors.lastname: Palovaara
authors.affiliation: Limnological Observatory of the Pyrenees (LOOP)-Department of Ecology, University of Barcelona Av. Diagonal 643, 08028 Barcelona, Spain Department of Environmental Chemistry, IDAEA-CSIC, C/Jordi Girona 18-26, 08034, Barcelona, Catalonia, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Vila-Costa
authors.affiliation: Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar-CSIC, Pg. Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain.
authors.forename: Guillem
authors.initials: G
authors.lastname: Salazar
authors.affiliation: Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar-CSIC, Pg. Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain.
authors.forename: Eva
authors.initials: E
authors.lastname: Calvo
authors.affiliation: Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar-CSIC, Pg. Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain.
authors.forename: Carles
authors.initials: C
authors.lastname: Pelejero
authors.affiliation: Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar-CSIC, Pg. Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain.
authors.forename: Cèlia
authors.initials: C
authors.lastname: Marrasé
authors.affiliation: Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar-CSIC, Pg. Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain.
authors.forename: Josep M
authors.initials: JM
authors.lastname: Gasol
authors.affiliation: Centre for Ecology and Evolution in Microbial Model Systems, EEMiS, Linnaeus University, Barlastgatan 11, SE-391 82 Kalmar, Sweden.
authors.forename: Jarone
authors.initials: J
authors.lastname: Pinhassi
mesh_terms: D059001:Aquatic Organisms / Q000382:microbiology; D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000254:growth & development*; D001483:Base Sequence; D044822:Biodiversity; D004269:DNA, Bacterial / Q000235:genetics; D017753:Ecosystem; D005068:Eutrophication; D006801:Humans; D006863:Hydrogen-Ion Concentration; D019083:Mediterranean Region; D064307:Microbiota / Q000235:genetics; D010933:Plankton / Q000254:growth & development*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012621:Seasons; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S
keywords: acidification; diversity; eutrophication; marine bacteria; rare biosphere