Dilution cultivation of marine heterotrophic bacteria abundant after a spring phytoplankton bloom in the North Sea.
The roles of individual bacterioplankton species in the re-mineralization of algal biomass are poorly understood. Evidence from molecular data had indicated that a spring diatom bloom in the German Bight of the North Sea in 2009 was followed by a rapid succession of uncultivated bacterioplankton species, including members of the genera Ulvibacter, Formosa, Polaribacter (class Flavobacteria) and Reinekea (class Gammaproteobacteria). We isolated strains from the same site during the diatom bloom in spring 2010 using dilution cultivation in an artificial seawater medium with micromolar substrate and nutrient concentrations. Flow cytometry demonstrated growth from single cells to densities of 10(4) -10(6) cells ml(-1) and a culturability of 35%. Novel Formosa, Polaribacter and Reinekea strains were isolated and had 16S rRNA gene sequence identities of > 99.8% with bacterioplankton in spring or summer 2009. Genomes of selected isolates were draft sequenced and used for read recruitment of metagenomes from bacterioplankton in 2009. Metagenome reads covered 93% of a Formosa clade B, 91% of a Reinekea and 74% of a Formosa clade A genome, applying a ≥ 94.5% nucleotide identity threshold. These novel strains represent abundant bacterioplankton species thriving on coastal phytoplankton blooms in the North Sea.
Department of Microbiology, Max Planck Institute for Marine Microbiology, Bremen, Germany.
Richard L
RL
Hahnke
Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, Bremen, Germany.
Christin M
CM
Bennke
Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, Bremen, Germany.
Bernhard M
BM
Fuchs
Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, Bremen, Germany.
Alexander J
AJ
Mann
Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl-von-Ossietzky-University, Oldenburg, Germany.
Erhard
E
Rhiel
Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, Bremen, Germany.
Hanno
H
Teeling
Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, Bremen, Germany.
Rudolf
R
Amann
Department of Microbiology, Max Planck Institute for Marine Microbiology, Bremen, Germany.
Jens
J
Harder
D001483:Base Sequence; D017377:Diatoms / Q000235:genetics / Q000254:growth & development; D005068:Eutrophication / Q000502:physiology*; D041965:Flavobacteriaceae / Q000145:classification* / Q000235:genetics; D020563:Gammaproteobacteria / Q000145:classification* / Q000235:genetics; D054892:Metagenome; D008969:Molecular Sequence Data; D009659:North Sea; D010839:Phytoplankton / Q000145:classification* / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012621:Seasons; D012623:Seawater / Q000382:microbiology
D012336:RNA, Ribosomal, 16S