title: Linking denitrifier community structure and prevalent biogeochemical parameters in the pelagial of the central Baltic Proper (Baltic Sea).
abstract: The oxic-anoxic interface of the water column of the Gotland Basin (central Baltic Sea) is characterised by defined biogeochemical gradients and is hypothesised to be a zone of pronounced denitrification. Our aim was to analyse the composition and distribution of pelagic denitrifying microorganisms in relation to the physico-chemical gradients in the water column. PCR-amplified nirS genes--coding for dissimilatory nitrite reductase--were analysed as functional markers by terminal restriction fragment length polymorphism and cloning. The overall nirS diversity was low, with the lowest levels found at the oxic-anoxic interface. Only a few terminal restriction fragments dominated the denitrifier communities throughout the water column, and these could be assigned to several new Baltic Sea clusters that were revealed by phylogenetic analysis. The novel clusters were separated in two groups corresponding to the oxygen concentrations within specific layers of the water column. Gradients of prevalent biogeochemical parameters (H(2)S, NH(4) (+), NO(3) (-) and O(2)) largely determined the composition of the nirS-type denitrifier communities within the water column of the Gotland Basin.
authors.affiliation: Baltic Sea Research Institute Warnemünde, Seestrasse 15, 18119 Rostock, Germany. michael.hannig@io-warnemuende.de
authors.forename: Michael
authors.initials: M
authors.lastname: Hannig
authors.forename: Gesche
authors.initials: G
authors.lastname: Braker
authors.forename: Joachim
authors.initials: J
authors.lastname: Dippner
authors.forename: Klaus
authors.initials: K
authors.lastname: Jürgens
mesh_terms: D001419:Bacteria / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D044822:Biodiversity; D004269:DNA, Bacterial / Q000235:genetics; D017753:Ecosystem; D008969:Molecular Sequence Data; D009572:Nitrite Reductases / Q000235:genetics; D017672:Nitrogen Compounds / Q000032:analysis*; D010100:Oxygen / Q000032:analysis*; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012623:Seawater / Q000737:chemistry* / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D014871:Water Microbiology
chemical_list: D004269:DNA, Bacterial; D017672:Nitrogen Compounds; D009572:Nitrite Reductases; D010100:Oxygen