title: Microbial community structure of sandy intertidal sediments in the North Sea, Sylt-Rømø Basin, Wadden Sea.
abstract: Molecular biological methods were used to investigate the microbial diversity and community structure in intertidal sandy sediments near the island of Sylt (Wadden Sea) at a site which was characterized for transport and mineralization rates in a parallel study (D. de Beer, F. Wenzhöfer, T. Ferdelman, S.E. Boehme, M. Huettel, J.E.E. van Beusekom, M.E. Böttcher, N. Musat, N. Dubilier, Transport and mineralization rates in North Sea sandy intertidal sediments, Sylt-Romo Basin, Wadden Sea, Limnol. Oceanogr. 50 (2005) 113-127). Comparative 16S rRNA sequence analysis revealed a high bacterial diversity. Most sequences retrieved by PCR with a general bacterial primer set were affiliated with Bacteroidetes, Gammaproteobacteria, Deltaproteobacteria and the Pirellula cluster of Planctomycetales. Fluorescence in situ hybridization (FISH) and slot-blot hybridization with group-specific rRNA-targeted oligonucleotide probes were used to characterize the microbial community structure over depth (0-12 cm) and seasons (March, July, October). We found high abundances of bacteria with total cell numbers up to 3 x 10(9) cells ml(-1) and a clear seasonal variation, with higher values in July and October versus March. The microbial community was dominated by members of the Planctomycetes, the Cytophaga/Flavobacterium group, Gammaproteobacteria, and bacteria of the Desulfosarcina/Desulfococcus group. The high abundance (1.5 x 10(7)-1.8 x 10(8) cells ml(-1) accounting for 3-19% of all cells) of presumably aerobic heterotrophic polymer-degrading planctomycetes is in line with the high permeability, deep oxygen penetration, and the high rates of aerobic mineralization of algal biomass measured in the sandy sediments by de Beer et al. (2005). The high and stable abundance of members of the Desulfosarcina/Desulfococcus group, both over depth and season, suggests that these bacteria may play a more important role than previously assumed based on low sulfate reduction rates in parallel cores (de Beer et al., 2005).
authors.affiliation: Max Planck Institute for Marine Microbiology, Celsiusstr. 1, D-28359 Bremen, Germany.
authors.forename: Niculina
authors.initials: N
authors.lastname: Musat
authors.forename: Ursula
authors.initials: U
authors.lastname: Werner
authors.forename: Katrin
authors.initials: K
authors.lastname: Knittel
authors.forename: Steffen
authors.initials: S
authors.lastname: Kolb
authors.forename: Tanja
authors.initials: T
authors.lastname: Dodenhof
authors.forename: Justus E E
authors.initials: JE
authors.lastname: van Beusekom
authors.forename: Dirk
authors.initials: D
authors.lastname: de Beer
authors.forename: Nicole
authors.initials: N
authors.lastname: Dubilier
authors.forename: Rudolf
authors.initials: R
authors.lastname: Amann
mesh_terms: D001419:Bacteria / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D044822:Biodiversity; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D017753:Ecosystem; D020459:Genes, rRNA / Q000235:genetics; D019015:Geologic Sediments / Q000382:microbiology*; D017404:In Situ Hybridization, Fluorescence; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009659:North Sea; D009693:Nucleic Acid Hybridization; D010802:Phylogeny; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012621:Seasons; D017422:Sequence Analysis, DNA; D013696:Temperature; D014871:Water Microbiology
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S