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:

Budgetary and biogeochemical implications of N2O isotope signatures in the Arabian Sea

Nature volume 394, pages 462–464 (1998)Cite this article

Abstract

Nitrous oxide (N2O) is an important greenhouse gas that also plays a role in the chemistry of stratospheric ozone depletion, but its atmospheric budget has yet to be well-quantified1,2,3,4,5. However, multi-isotope characterization of N2O emitted from various natural sources is a potentially powerful tool for providing the much-needed constraints. It is generally believed that production of isotopically light (low 15N/14N and 18O/16O ratios) N2O occurs in the upper ocean through nitrification process, and that the flux of this light N2O from sea to air isotopically counters the flux of heavy N2O from the stratosphere to the troposphere1,2. But eastern-boundary ocean-upwelling zones, which contain oxygen-depleted waters and are sites of intense N2O efflux6,7,8,9,10, have not been adequately studied. We show here, using new isotope data, that in spite of huge denitrification-related enrichments of 15N and 18O in N2O at mid-depths in the Arabian Sea, N2O emitted from upwelled waters is only slightly enriched in 18O, and moderately depleted in 15N, relative to air. These opposing isotopic signatures and modest departures from the isotopic composition of tropospheric N2O indicate that air–sea exchange cannot — given the heavy isotopic signature of N2O derived from the stratosphere — allow the tropospheric budget of N2O to be closed without invoking hitherto-unknown N2O sources and sinks. Our oceanic data cannot be explained through either nitrification or denitrification alone, such that a coupling between the two processes may be an important mechanism of N2O production.

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

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

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

Figure 1: Natural isotope ratios (δ15N and δ18O relative to air) in dissolved N2O as a function of N2O saturation at the sea surface (depth < 5 m).
Figure 2: Vertical profiles of δ15N and δ18O (% relative to air) of N2O (a), δ15N of NO3− (b), and concentrations of N2O (c), NO2− (d) and O2 (e) at stations SS 3201 (17° N, 68° E; filled circles, joined by dotted lines) and SS 3204 (19.75° N, 64.62° E; filled triangles, joined by continuous lines).
Figure 3: Comparison of natural isotope data from this study with representative data from other environments1,4.

Similar content being viewed by others

References

  1. 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 

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

    Article  ADS  CAS  Google Scholar 

  3. Cliff, S. S. & Thiemens, M. H. The 18O/16O and 17O/16O ratios in atmospheric nitrous oxide: a mass-dependent anomaly. Science 278, 1774–1776 (1997).

    Article  ADS  CAS  Google Scholar 

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

    Article  ADS  CAS  Google Scholar 

  5. Yung, Y. L. & Miller, C. E. Isotopic fractionation of stratospheric nitrous oxide: is there a chemical source? Science 278, 1778–1780 (1997).

    Article  ADS  CAS  Google Scholar 

  6. Codispoti, L. A. & Christensen, 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 

  7. 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 

  8. Codispoti, L. A. et al. in Oceanography of the Indian Ocean (ed. Desai, B. N.) 271–284 (Oxford-IBH, New Delhi, (1992)).

    Google Scholar 

  9. Bange, H. W., Rapsomanikis, S. & Andreae, M. O. Nitrous oxide in coastal waters. Glob. Biogeochem. Cycles 10, 197–207 (1996).

    Article  ADS  CAS  Google Scholar 

  10. Bange, H. W., Rapsomanikis, S. & Andreae, M. O. Nitrous oxide emissions from the Arabian Sea. Geophys. Res. Lett. 23, 3175–3178 (1996).

    Article  ADS  CAS  Google Scholar 

  11. Capone, D. G. Abiologically constrained estimate of oceanic N2O flux. Mitt. Internat. Verein. Limnol. 25, 105–114 (1996).

    Google Scholar 

  12. de Wilde, H. P. J. & Helder, W. Nitrous oxide in the Somali Basin: the role of upwelling. Deep-Sea Res. II 44, 1319–1340 (1997).

    Article  ADS  CAS  Google Scholar 

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

    Article  ADS  CAS  Google Scholar 

  14. Yoshida, N. 15N-depleted N2O as a product of nitrification. Nature 335, 528–529 (1988).

    Article  ADS  CAS  Google Scholar 

  15. 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 

  16. Naqvi, W. A. Geographical extent of denitrification in the Arabian Sea in relation to some physical processes. Oceanol. Acta 14, 281–290 (1991).

    CAS  Google Scholar 

  17. Yoshida, N. et al. Nitrification rates and 15N abundances of N2O and NO3in the western North Pacific. Nature 342, 895–897 (1989).

    Article  ADS  CAS  Google Scholar 

  18. 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 

  19. Burkill, P. H., Mantoura, R. F. C. & Owens, N. J. P. Biogeochemical cycling in the northwestern Indian Ocean: a brief overview. Deep-Sea Res. II 40, 643–649 (1993).

    Article  ADS  Google Scholar 

  20. Prasad, S. S. Natural atmospheric sources and sinks of nitrous oxide. I. An evaluation based on ten laboratory data. J. Geophys. Res. 99, 5285–5294 (1994).

    Article  ADS  CAS  Google Scholar 

  21. Betlach, M. R. & Tiedje, J. M. Kinetic explanation for accumulation of nitrite, nitric oxide and nitrous oxide during bacterial denitrification. Appl. Environ. Microbiol. 42, 1074–1084 (1981).

    CAS  PubMed  PubMed Central  Google Scholar 

  22. Naqvi, S. W. A. N2O production in the ocean. Nature 349, 373–374 (1991).

    Article  ADS  Google Scholar 

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

    Article  ADS  Google Scholar 

  24. Ward, B. B. & Zafiriou, O. C. Nitrification and nitric oxide in the oxygen minimum of the eastern tropical North Pacific. Deep-Sea Res. 35, 1127–1142 (1988).

    Article  ADS  CAS  Google Scholar 

  25. Dua, R. D., Bhandari, B. & Nicholas, D. J. D. Stable isotope studies in the oxidation of ammonia to hydroxylamine by Nitrosomonas europaea. FEBS Lett. 106, 401–404 (1979).

    Article  CAS  Google Scholar 

  26. Ostlund, H. G., Craig, H., Broecker, W. S. & Spencer, D. GEOSECS Atlantic, Pacific and Indian Ocean Expeditions Vol. 7, Shorebased Data and Graphics (NSF, Washington, DC, (1987)).

    Google Scholar 

  27. Altabet, M. A., Francois, R., Murray, D. W. & Prell, W. L. Climate-related variations in denitrification in the Arabian Sea from sediment 15N/14N ratios. Nature 373, 506–509 (1995).

    Article  ADS  CAS  Google Scholar 

  28. Leuenberger, M. & Siegenthaler, U. Ice-age atmospheric concentration of nitrous oxide from an Antarctic ice core. Nature 360, 449–451 (1992).

    Article  ADS  CAS  Google Scholar 

  29. Brandes, J. A. & Devol, A. H. Isotopic fractionation of oxygen and nitrogen in coastal marine sediments. Geochim. Cosmochim. Acta 61, 1793–1802 (1997).

    Article  ADS  CAS  Google Scholar 

  30. Weiss, R. F. & Price, B. A. Nitrous oxide solubility in water and seawater. Mar. Chem. 8, 347–359 (1980).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

We thank E. Desa and B.J. Zahuranec for their encouragement and support; the Department of Ocean Development (India), especially V. Ravindranathan, for making time on the research vessels available; and C. Nasnolkar, V.V.S.S. Sarma and M. Kuhland for their technical assistance. This work was supported by the Office of Naval Research (USA) through the US–India Fund.

Author information

Author notes

  1. J. A. Brandes

    Present address: Geophysical Laboratory, Carnegie Institution of Washington, Washington DC, 20015, USA

Authors and Affiliations

  1. National Institute of Oceanography, Dona Paula, 403 004, Goa, India

    S. W. A. Naqvi, D. A. Jayakumar & P. V. Narvekar

  2. New York State Department of Health, Wadsworth Center, and School of Public Health, State University of New York at Albany, PO Box 509, Albany, 12201, New York, USA

    T. Yoshinari

  3. Department of Chemistry and Biochemistry, and Center for Marine Science and Technology, University of Massachusetts, Dartmouth, North Dartmouth, 02747, Massachusetts, USA

    M. A. Altabet

  4. School of Oceanography, University of Washington, Seattle, 98195, Washington, USA

    A. H. Devol & J. A. Brandes

  5. Center for Coastal Physical Oceanography, Old Dominion University, Norfolk, 23529, Virginia, USA

    L. A. Codispoti

Authors
  1. S. W. A. Naqvi
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. T. Yoshinari
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. D. A. Jayakumar
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. M. A. Altabet
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. P. V. Narvekar
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. A. H. Devol
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. J. A. Brandes
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. L. A. Codispoti
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to S. W. A. Naqvi.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Naqvi, S., Yoshinari, T., Jayakumar, D. et al. Budgetary and biogeochemical implications of N2O isotope signatures in the Arabian Sea. Nature 394, 462–464 (1998). https://doi.org/10.1038/28828

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/28828

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

Advanced 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