• Login
    About WHOAS
    View Item 
    •   WHOAS Home
    • Woods Hole Oceanographic Institution
    • Marine Chemistry and Geochemistry (MC&G)
    • View Item
    •   WHOAS Home
    • Woods Hole Oceanographic Institution
    • Marine Chemistry and Geochemistry (MC&G)
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of WHOASCommunities & CollectionsBy Issue DateAuthorsTitlesKeywordsThis CollectionBy Issue DateAuthorsTitlesKeywords

    My Account

    LoginRegister

    Statistics

    View Usage Statistics

    N-loss isotope effects in the Peru oxygen minimum zone studied using a mesoscale eddy as a natural tracer experiment

    Thumbnail
    View/Open
    Article (6.924Mb)
    Supplementary information (121.5Kb)
    Date
    2015-06-06
    Author
    Bourbonnais, Annie  Concept link
    Altabet, Mark A.  Concept link
    Charoenpong, Chawalit N.  Concept link
    Larkum, Jennifer  Concept link
    Hu, Haibei  Concept link
    Bange, Hermann W.  Concept link
    Stramma, Lothar  Concept link
    Metadata
    Show full item record
    Citable URI
    https://hdl.handle.net/1912/7464
    As published
    https://doi.org/10.1002/2014GB005001
    DOI
    10.1002/2014GB005001
    Keyword
     Mesoscale eddy; Isotope effects; N-loss 
    Abstract
    Mesoscale eddies in Oxygen Minimum Zones (OMZs) have been identified as important fixed nitrogen (N) loss hotspots that may significantly impact both the global rate of N-loss as well as the ocean's N isotope budget. They also represent “natural tracer experiments” with intensified biogeochemical signals that can be exploited to understand the large-scale processes that control N-loss and associated isotope effects (ε; the ‰ deviation from 1 in the ratio of reaction rate constants for the light versus heavy isotopologues). We observed large ranges in the concentrations and N and O isotopic compositions of nitrate (NO3−), nitrite (NO2−), and biogenic N2 associated with an anticyclonic mode-water eddy in the Peru OMZ during two cruises in November and December 2012. In the eddy's center where NO3− was nearly exhausted, we measured the highest δ15N values for both NO3− and NO2− (up to ~70‰ and 50‰) ever reported for an OMZ. Correspondingly, N deficit and biogenic N2-N concentrations were also the highest near the eddy's center (up to ~40 µmol L−1). δ15N-N2 also varied with biogenic N2 production, following kinetic isotopic fractionation during NO2− reduction to N2 and, for the first time, provided an independent assessment of N isotope fractionation during OMZ N-loss. We found apparent variable ε for NO3− reduction (up to ~30‰ in the presence of NO2−). However, the overall ε for N-loss was calculated to be only ~13–14‰ (as compared to canonical values of ~20–30‰) assuming a closed system and only slightly higher assuming an open system (16–19‰). Our results were similar whether calculated from the disappearance of DIN (NO3− + NO2−) or from the appearance of N2 and changes in isotopic composition. Further, we calculated the separate ε values for NO3− reduction to NO2− and NO2− reduction to N2 of ~16–21‰ and ~12‰, respectively, when the effect of NO2− oxidation could be removed. These results, together with the relationship between N and O of NO3− isotopes and the difference in δ15N between NO3− and NO2−, confirm a role for NO2− oxidation in increasing the apparent ε associated with NO3− reduction. The lower ε for N-loss calculated in this study could help reconcile the current imbalance in the global N budget if representative of global OMZ N-loss.
    Description
    Author Posting. © American Geophysical Union, 2015. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 29 (2015): 793-811, doi:10.1002/2014GB005001.
    Collections
    • Marine Chemistry and Geochemistry (MC&G)
    Suggested Citation
    Global Biogeochemical Cycles 29 (2015): 793-811
     

    Related items

    Showing items related by title, author, creator and subject.

    • Thumbnail

      The effects of mesoscale ocean–atmosphere coupling on the large-scale ocean circulation 

      Hogg, Andrew Mc C.; Dewar, William K.; Berloff, Pavel S.; Kravtsov, Sergey K.; Hutchinson, David K. (American Meteorological Society, 2009-08-01)
      Small-scale variation in wind stress due to ocean–atmosphere interaction within the atmospheric boundary layer alters the temporal and spatial scale of Ekman pumping driving the double-gyre circulation of the ocean. A ...
    • Thumbnail

      Effects of eddy vorticity forcing on the mean state of the Kuroshio Extension 

      Delman, Andrew S.; McClean, Julie L.; Sprintall, Janet; Talley, Lynne D.; Yulaeva, Elena; Jayne, Steven R. (American Meteorological Society, 2015-05)
      Eddy–mean flow interactions along the Kuroshio Extension (KE) jet are investigated using a vorticity budget of a high-resolution ocean model simulation, averaged over a 13-yr period. The simulation explicitly resolves ...
    • Thumbnail

      Effects of oceanic mesoscale and submesoscale frontal processes on the vertical transport of phytoplankton 

      Ruiz, Simon; Claret, Mariona; Pascual, Ananda; Olita, Antonio; Troupin, Charles; Capet, Arthur; Tovar-Sánchez, Antonio; Allen, John T.; Poulain, Pierre Marie; Tintoré, Joaquín; Mahadevan, Amala (American Geophysical Union, 2019-07-23)
      Oceanic fronts are dynamically active regions of the global ocean that support upwelling and downwelling with significant implications for phytoplankton production and export. However (on time scales urn:x-wiley:jgrc:me ...
    All Items in WHOAS are protected by original copyright, with all rights reserved, unless otherwise indicated. WHOAS also supports the use of the Creative Commons licenses for original content.
    A service of the MBLWHOI Library | About WHOAS
    Contact Us | Send Feedback | Privacy Policy
    Core Trust Logo