title: Nitrous oxide as a function of oxygen and archaeal gene abundance in the North Pacific.
abstract: Oceanic oxygen minimum zones are strong sources of the potent greenhouse gas N2O but its microbial source is unclear. We characterized an exponential response in N2O production to decreasing oxygen between 1 and 30 μmol O2l-1within and below the oxycline using15NO2-, a relationship that held along a 550 km offshore transect in the North Pacific. Differences in the overall magnitude of N2O production were accounted for by archaeal functional gene abundance. A one-dimensional (1D) model, parameterized with our experimentally derived exponential terms, accurately reproduces N2O profiles in the top 350 m of water column and, together with a strong45N2O signature indicated neither canonical nor nitrifier-denitrification production while statistical modelling supported production by archaea, possibly via hybrid N2O formation. Further, with just archaeal N2O production, we could balance high-resolution estimates of sea-to-air N2O exchange. Hence, a significant source of N2O, previously described as leakage from bacterial ammonium oxidation, is better described by low-oxygen archaeal production at the oxygen minimum zone's margins.
authors.affiliation: School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK.
authors.forename: Mark
authors.identifier: 0000-0002-9859-5537
authors.initials: M
authors.lastname: Trimmer
authors.affiliation: School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK.
authors.forename: Panagiota-Myrsini
authors.initials: PM
authors.lastname: Chronopoulou
authors.affiliation: School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK.
authors.forename: Susanna T
authors.initials: ST
authors.lastname: Maanoja
authors.affiliation: School of Marine Science and Technology, Ridley Building, University of Newcastle, Newcastle upon, Tyne NE1 7RU, UK.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Upstill-Goddard
authors.affiliation: Plymouth Marine Laboratory, Prospect Place, West Hoe, Plymouth PL1 3DH, UK.
authors.forename: Vassilis
authors.initials: V
authors.lastname: Kitidis
authors.affiliation: School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK.
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Purdy
mesh_terms: D000388:Air; D001105:Archaea / Q000235:genetics* / Q000378:metabolism*; D019766:Genes, Archaeal; D007553:Isotope Labeling; D016014:Linear Models; D008954:Models, Biological; D009587:Nitrogen Isotopes; D009609:Nitrous Oxide / Q000378:metabolism*; D017711:Nonlinear Dynamics; D010100:Oxygen / Q000378:metabolism*; D010140:Pacific Ocean; D014867:Water
chemical_list: D009587:Nitrogen Isotopes; D014867:Water; D009609:Nitrous Oxide; D010100:Oxygen