Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

A large source of atmospheric nitrous oxide from subtropical North Pacific surface waters

Abstract

Nitrous oxide (N2O), a trace gas whose concentration is increasing in the atmosphere, plays an important role in both radiative forcing and stratospheric ozone depletion1,2. Its biogeochemical cycle has thus come under intense scrutiny in recent years. Despite these efforts, the global budget of N2O remains unresolved, and the nature and magnitude of the sources and sinks continue to be debated3,4,5 despite the constraints that can be provided by characterizations of the gas6,7. We report here the results of dual-isotope measurements of N2O from the water column of the subtropical North Pacific Ocean. Nitrous oxide within the lower-euphotic and upper-aphotic zones is depleted in both 15N and 18O relative to its tropospheric and deep-ocean composition. These findings are consistent with a prediction, based on global mass-balance considerations, of a near-surface isotopically depleted oceanic N2O source4. Our results indicate that this source, probably produced by bacterial nitrification, contributes significantly to the ocean–atmosphere flux of N2O in the oligotrophic subtropical North Pacific Ocean. This source may act to buffer the isotopic composition of tropospheric N2O, and is quantitatively significant in the global tropospheric N2O budget. Because dissolved gases in near-surface waters are more readily exchanged with the atmospheric reservoir than those in deep waters, the existence of a quantitatively significant N2O source at a relatively shallow depth has potentially important implications for the susceptibility of the source, and the ocean–atmosphere flux, to climatic influences.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Isotope data from station ALOHA.
Figure 2: Property–property plot of oxygen- and nitrogen-isotope composition of N2O.

Similar content being viewed by others

References

  1. Houghton, J. T., Jenkins, G. J. & Ephraums, J. J. (eds) Climate Change: The IPCC Scientific Assessment(Cambridge Univ. Press, (1990)).

    Google Scholar 

  2. Crutzen, P. J. The influence of nitrogen oxides on the atmospheric ozone content. Q. J. R. Meteorol. Soc. 96, 320–325 (1970).

    Article  ADS  Google Scholar 

  3. Bouwman, A. F., Van der Hoek, K. W. & Olivier, J. G. J. Uncertainties in the global source distribution of nitrous oxide. J. Geophys. Res. 100, 2785–2800 (1995).

    Article  ADS  CAS  Google Scholar 

  4. Kim, K.-R. & Craig, H. Nitrogen-15 and oxygen-18 characteristics of nitrous oxide: a global perspective. Science 262, 1855–1857 (1993).

    Article  ADS  CAS  Google Scholar 

  5. McElroy, M. B. & Jones, D. B. A. Evidence for an additional source of atmospheric N2O. Glob. Biogeochem. Cycles 10, 651–659 (1996).

    Article  ADS  CAS  Google Scholar 

  6. Kim, K.-R. & Craig, H. Two-isotope characterization of N2O in the Pacific Ocean and constraints on its origin in deep water. Nature 347, 58–61 (1990).

    Article  ADS  CAS  Google Scholar 

  7. Zafiriou, O. Laughing gas from leaky pipes. Nature 347, 15–16 (1990).

    Article  ADS  Google Scholar 

  8. Karl, D. M. & Lukas, R. The Hawaii Ocean Time-series (HOT) program: background, rationale and field implementation. Deep-Sea Res. II 43, 129–156 (1996).

    Article  ADS  CAS  Google Scholar 

  9. Alldredge, A. L. & Cohen, Y. Can microscale chemical patches persist in the sea? Microelectrode study of marine snow, fecal pellets. Science 235, 689–691 (1987).

    Article  ADS  CAS  Google Scholar 

  10. Yoshida, N., Hattori, A., Saino, T., Matsuo, S. & Wada, E. 15N/14N ratio of dissolved N2O in the eastern tropical Pacific Ocean. Nature 307, 442–444 (1984).

    Article  ADS  CAS  Google Scholar 

  11. Yamazaki, T., Yoshida, N., Wada, E. & Matsuo, S. N2O reduction by Azotobacter vinelandii with emphasis on kinetic isotope effects. Plant Cell Physiol. 28, 263–271 (1989).

    Google Scholar 

  12. Ward, B. B. in Nitrification(ed. Prosser, J. I.) 157–184 (IRL, Oxford, (1986)).

    Google Scholar 

  13. Dore, J. E. & Karl, D. M. Nitrification in the euphotic zone as a source for nitrite, nitrate and nitrous oxide at Station ALOHA. Limnol. Oceanogr. 41, 1619–1628 (1996).

    Article  ADS  CAS  Google Scholar 

  14. Yoshida, N. 15N-depleted N2O as a product of nitrification. Nature 355, 528–529 (1988).

    Article  ADS  Google Scholar 

  15. Yoshinari, T. & Wahlen, M. Oxygen isotope ratios in N2O from nitrification at a wastewater treatment facility. Nature 317, 349–350 (1985).

    Article  ADS  CAS  Google Scholar 

  16. Li, Y.-H., Peng, T.-H., Broecker, W. S. & Östlund, H. G. The average vertical mixing coefficient for the oceanic thermocline. Tellus B 36, 212–217 (1984).

    Article  ADS  Google Scholar 

  17. Jørgensen, B. B. Atheoretical model of the stable sulfur isotope distribution in marine sediments. Geochim. Cosmochim. Acta 43, 363–374 (1979).

    Article  ADS  Google Scholar 

  18. Nevison, C. D., Weiss, R. F. & Erickson, D. J. Global oceanic emissions of nitrous oxide. J. Geophys. Res. 100, 15809–15820 (1995).

    Article  ADS  CAS  Google Scholar 

  19. Rahn, T. & Wahlen, M. Stable isotope enrichment in stratospheric nitrous oxide. Science 278, 1776–1778 (1997).

    Article  ADS  CAS  Google Scholar 

  20. Codispoti, L. A. & Christiansen, J. P. Nitrification, denitrification and nitrous oxide cycling in the eastern tropical South Pacific Ocean. Mar. Chem. 16, 277–300 (1985).

    Article  CAS  Google Scholar 

  21. Law, C. S. & Owens, N. J. P. Significant flux of atmospheric nitrous oxide from the northwest Indian Ocean. Nature 346, 826–828 (1990).

    Article  ADS  CAS  Google Scholar 

  22. Naqvi, S. W. A. & Noronha, R. J. Nitrous oxide in the Arabian Sea. Deep-Sea Res. 38, 871–890 (1991).

    Article  ADS  CAS  Google Scholar 

  23. Yoshinari, T.et al. Nitrogen and oxygen isotopic composition of N2O from suboxic waters of the eastern tropical North Pacific and the Arabian Sea — measurement by continuous-flow isotope-ratio monitoring. Mar. Chem. 56, 253–264 (1997).

    Article  CAS  Google Scholar 

  24. Naqvi, S. W. A.et al. Budgetary and biogeochemical implications of N2O isotope signatures in the Arabian Sea. Nature 394, 462–464 (1998).

    Article  ADS  CAS  Google Scholar 

  25. Cline, J. D., Wisegarver, D. P. & Kelly-Hansen, K. Nitrous oxide and vertical mixing in the equatorial Pacific during the 1982–1983 El Niño. Deep-Sea Res. 34, 857–873 (1987).

    Article  ADS  CAS  Google Scholar 

  26. Karl, D. M.et al. Ecosystem changes in the North Pacific subtropical gyre attributed to the 1991–92 El Niño. Nature 373, 230–234 (1995).

    Article  ADS  CAS  Google Scholar 

  27. Sansone, F. J., Popp, B. N. & Rust, T. M. Stable carbon isotopic analysis of low-level methane in water and gas. Anal. Chem. 69, 40–44 (1997).

    Article  CAS  Google Scholar 

  28. Popp, B. N., Sansone, F. J., Rust, T. M. & Merritt, D. A. Determination of concentration and carbon isotopic composition of dissolved methane in sediments and nearshore waters. Anal. Chem. 67, 405–411 (1995).

    Article  CAS  Google Scholar 

  29. Craig, H. Isotopic standards for carbon and oxygen and correction factors for mass-spectrometric analysis of carbon dioxide. Geochim. Cosmochim. Acta 12, 133–149 (1957).

    Article  ADS  CAS  Google Scholar 

  30. Brand, W. A. PRECON: a fully automated interface for the pre-GC concentration of trace gases in air for isotopic analyses. Isotopes Environ. Health Stud. 31, 277–284 (1995).

    Article  CAS  Google Scholar 

  31. Yoshida, N. & Matsuo, S. Nitrogen isotope ratio of atmospheric N2O as a key to the global cycle of N2O. Geochem. J. 17, 231–239 (1983).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

We thank the members of the Hawaii Ocean Time-series (HOT) program and M.E.Holmes for sample collection, and T. Rust for technical support. This research was supported by the US National Science Foundation.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to John E. Dore.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Dore, J., Popp, B., Karl, D. et al. A large source of atmospheric nitrous oxide from subtropical North Pacific surface waters. Nature 396, 63–66 (1998). https://doi.org/10.1038/23921

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/23921

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing