%0 Journal Article
%T Nitrous oxide distribution and its origin in the central and eastern South Pacific Subtropical Gyre
%+ Programa de Postgrado
%+ Centro de Investigación Oceanográfica en el Pacífico Sur Oriental (COPAS)
%+ Frontier Collaborative Research Center (FCRC)
%+ SORST project
%+ Faculty of Environment and Resource Studies
%+ Laboratoire d'océanographie et de biogéochimie (LOB)
%A Charpentier, J.
%A Farias, L.
%A Yoshida, N.
%A Boontanon, N.
%A Raimbault, Patrick
%< avec comité de lecture
%@ 1810-6277
%J Biogeosciences Discussions
%I European Geosciences Union
%V 4
%N 3
%P 1673-1702
%8 2007-05-25
%D 2007
%Z Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO]
%Z Sciences of the Universe [physics]/Astrophysics [astro-ph]
%Z Sciences of the Universe [physics]/Continental interfaces, environment
%Z Sciences of the Universe [physics]/Ocean, Atmosphere
%Z Sciences of the Universe [physics]/Earth SciencesJournal articles
%X The biogeochemical mechanism of bacterial N<sub>2</sub>O production in the ocean has been the subject of many discussions in recent years. New isotopomeric tools can help further knowledge on N<sub>2</sub>O sources in natural environments. This research shows and compares hydrographic, nitrous oxide concentration, and N<sub>2</sub>O isotopic and isotopomeric data from three stations across the South Pacific Ocean, from the center of the subtropical oligotrophic gyre (~26° S; 114° W) to the upwelling zone along the central Chilean coast (~34° S). Althought AOU/N<sub>2</sub>O and NO<sub>3</sub><sup>-</sup> trends support the idea that most of N<sub>2</sub>O source (mainly from intermediate water (200–1000 m)) come from nitrification, N<sub>2</sub>O isotopomeric composition (intramolecular distribution of <sup>15</sup>N isotopes in N<sub>2</sub>O) reveals an abrupt change in the mechanism of nitrous oxide production, always observed through lower SP (site preference of <sup>15</sup>N), at a high – stability layer, where particles could act as microsites and N<sub>2</sub>O would be produced by nitrifier denitrification (reduction of nitrite to nitrous oxide mediated by primary nitrifiers). There, nitrifier denitrification can account for 40% and 50% (center and east border of the gyre, respectively) of the nitrous oxide produced in this specific layer. This process could be associated with the deceleration of sinking organic particles in highly stable layers of the water column. In constrast, coastal upwelling system is characterized by oxygen deficient condition and some N deficit in a eutrophic system. Here, nitrous oxide accumulates up to 480% saturation, and isotopic and isotopomer signal show highly complex nitrous oxide production processes, which presumably reflect both the effect of nitrification and denitrification at low oxygen levels on N<sub>2</sub>O production, but non N<sub>2</sub>O consumption by denitrification was observed.
%G English
%2 https://hal.science/hal-00330241/document
%2 https://hal.science/hal-00330241/file/bgd-4-1673-2007.pdf
%L hal-00330241
%U https://hal.science/hal-00330241
%~ INSU
%~ CNRS
%~ UNIV-AMU
%~ EGU
%~ EGU-BGD
%~ GIP-BE
%~ LOPB
%~ TEST3-HALCNRS