title: Marine Non-Cyanobacterial Diazotrophs: Moving beyond Molecular Detection.
abstract: The nitrogen input through biological N2fixation is essential for life in vast areas of the global ocean. The belief is that cyanobacteria are the only relevant N2-fixing (diazotrophic) organisms. It has, however, now become evident that non-cyanobacterial diazotrophs, bacteria and archaea with ecologies fundamentally distinct from those of cyanobacteria, are widespread and occasionally fix N2at significant rates. The documentation of a globally relevant nitrogen input from these diazotrophs would constitute a new paradigm for research on oceanic nitrogen cycling. Here we highlight the need for combining rate measurements and molecular analyses of field samples with cultivation studies in order to clarify the ecology of non-cyanobacteria and their contribution to marine N2fixation on local and global scales.
authors.affiliation: Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark.
authors.forename: Deniz
authors.initials: D
authors.lastname: Bombar
authors.affiliation: Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark.
authors.forename: Ryan W
authors.initials: RW
authors.lastname: Paerl
authors.affiliation: Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark. Electronic address: lriemann@bio.ku.dk.
authors.forename: Lasse
authors.initials: L
authors.lastname: Riemann
mesh_terms: D001105:Archaea / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D001419:Bacteria / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D000458:Cyanobacteria / Q000201:enzymology / Q000378:metabolism*; D004463:Ecology; D052836:Heterotrophic Processes; D009584:Nitrogen / Q000378:metabolism; D058458:Nitrogen Cycle; D009586:Nitrogen Fixation / Q000502:physiology*; D009591:Nitrogenase / Q000235:genetics; D009792:Oceans and Seas; D010088:Oxidoreductases / Q000145:classification; D010802:Phylogeny; D012623:Seawater / Q000382:microbiology*
chemical_list: D010088:Oxidoreductases; D009591:Nitrogenase; C029130:nitrogenase reductase; D009584:Nitrogen
keywords: biogeochemistry; diazotroph; heterotrophic.; nifH; nitrogen fixation; ocean