{
  "abstract": "Unlike dissolved inorganic nitrogen, which is scarce in much of the tropical, subtropical, and temperate surface ocean, dissolved organic nitrogen (DON) has significant concentrations and gradients. Accordingly, the lateral transport of DON may fuel biological productivity in nutrient-depleted low-latitude surface waters. Here, we report measurements of the concentration and 15N/14N ratio (δ15N) of DON in surface waters over the Pacific and Atlantic basins. DON concentration is generally highest in subpolar and equatorial waters, with minima in the subtropical gyres. A δ15N correlation is observed between surface DON and the nitrate consumed in the surface waters, indicating in situ DON production and consumption. Samples with lower DON concentrations tend to have anomalously high DON δ15N, confirming net DON transport to, and consumption in, the subtropical gyres. Net local DON production or consumption appears to dominate the observed spatial variation in the DON-to-subsurface nitrate δ15N difference. For example, N2 fixation tends to lower the δ15N of surface DON relative to subsurface nitrate mostly through encouraging DON accumulation rather than by the specific δ15N of the nitrogen introduced by N2 fixation. Unique conditions appear to apply in the equatorial Atlantic, where despite high productivity, a local minimum in DON concentration and a slight elevation in DON δ15N suggest net DON degradation. In this phosphorus-rich, nitrogen-poor upwelling environment where low iron may restrict N2 fixation, net decomposition of DON may supply needed recycled nitrogen to the ecosystem.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Geosciences, Princeton University, Princeton, NJ 08544",
    "Climate Geochemistry Department, Max Planck Institute for Chemistry, Mainz 55128, Germany",
    "Division of Biosphere Sciences and Engineering, Carnegie Institution for Science, Pasadena, CA 91125",
    "Oceanography Department, Texas A&M University, College Station, TX 77843",
    "Department of Geosciences, Environment and Society, Université Libre de Bruxelles, Brussels 1050, Belgium",
    "Department of Oceanography, University of Cape Town, Rondebosch 7700, South Africa",
    "Marine and Antarctic Research Centre for Innovation and Sustainability, University of Cape Town, Rondebosch 7700, South Africa",
    "College of Marine Science, University of South Florida, St. Petersburg, FL 33701",
    "Department of Earth and Planetary Sciences, ETH Zürich, Zürich 8092, Switzerland"
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 11,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "Yeongjun Ryu",
      "orcid": "0000-0002-3509-8082"
    },
    {
      "affs": [
        0
      ],
      "name": "Dario Marconi"
    },
    {
      "affs": [
        2
      ],
      "name": "Zhou Liang"
    },
    {
      "affs": [
        3
      ],
      "name": "Angela N. Knapp",
      "orcid": "0000-0001-5575-3382"
    },
    {
      "affs": [
        4
      ],
      "name": "François Fripiat",
      "orcid": "0000-0002-2591-6301"
    },
    {
      "affs": [
        5,
        6
      ],
      "name": "Sarah E. Fawcett",
      "orcid": "0000-0002-0878-6496"
    },
    {
      "affs": [
        7
      ],
      "name": "Patrick A. Rafter"
    },
    {
      "affs": [
        0
      ],
      "name": "Sergey Oleynik"
    },
    {
      "affs": [
        1
      ],
      "name": "Alfredo Martínez-García"
    },
    {
      "affs": [
        1,
        8
      ],
      "name": "Gerald H. Haug"
    },
    {
      "affs": [
        0
      ],
      "name": "Daniel M. Sigman",
      "orcid": "0000-0002-7923-1973"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/fbatzswgn5a7x.bib",
  "cited_by": 0,
  "doi": "10.1073/pnas.2530315123",
  "fulltext_url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC13732207/",
  "id": "fbatzswgn5a7x",
  "issns": [
    "0027-8424",
    "1091-6490"
  ],
  "landing_url": "https://doi.org/10.1073/pnas.2530315123",
  "language": "en",
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "heading",
      "417"
    ],
    [
      "heading",
      "Biological Sciences"
    ],
    [
      "heading",
      "Environmental Sciences"
    ],
    [
      "openalex",
      "1910|Marine Plankton and Biogeochemistry"
    ]
  ],
  "openalex": "W7224094169",
  "pdf_url": null,
  "pmcid": "PMC13732207",
  "pmid": "42949967",
  "published": "2026-10-28",
  "publisher": "National Academy of Sciences",
  "ris": "https://research.draconitic.com/paper/fbatzswgn5a7x.ris",
  "sources": [
    {
      "first_seen": "2026-11-08T12:22:14Z",
      "native_id": "PMC13732207",
      "source": "pmc",
      "url": "https://doi.org/10.1073/pnas.2530315123"
    }
  ],
  "subjects": [
    {
      "field": "earth",
      "origin": "heading:Environmental Sciences",
      "subfield": "environmental-science"
    }
  ],
  "title": "Isotopic evidence of dissolved organic nitrogen production and consumption in ocean surface waters",
  "title_text": "Isotopic evidence of dissolved organic nitrogen production and consumption in ocean surface waters",
  "type": "peer-reviewed",
  "updated_at": "2026-11-08T12:22:14Z",
  "url": "https://research.draconitic.com/paper/fbatzswgn5a7x",
  "venue": "Proceedings of the National Academy of Sciences of the United States of America",
  "versions": []
}