Skip to main content

Thank you for visiting 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.

Response of N2O production rate to ocean acidification in the western North Pacific


Ocean acidification, induced by the increase in anthropogenic CO2 emissions, has a profound impact on marine organisms and biogeochemical processes1. The response of marine microbial activities to ocean acidification might play a crucial role in the future evolution of air–sea fluxes of biogenic gases such as nitrous oxide (N2O), a strong GHG and the dominant stratospheric ozone-depleting substance2. Here, we examine the response of N2O production from nitrification to acidification in a series of incubation experiments conducted in subtropical and subarctic western North Pacific. The experiments show that when pH was reduced, the N2O production rate during nitrification measured at subarctic stations increased significantly while nitrification rates remained stable or decreased. Contrary to previous findings, these results suggest that the effect of ocean acidification on N2O production during nitrification and nitrification rates are probably uncoupled. Collectively, these results suggest that if seawater pH continues to decline at the same rate, ocean acidification could increase marine N2O production during nitrification in the subarctic North Pacific by 185 to 491% by the end of the century.

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

Access options

Rent or buy this article

Prices vary by article type



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

Fig. 1: Experiment and sampling stations.
Fig. 2: Response of nitrification and nitrous oxide production rates to simulated ocean acidification.
Fig. 3: Nitrification and nitrifier denitrification pathways.

Data availability

The authors declare that the data supporting the findings of this study are available within the article and its Supplementary Information and at at


  1. Beman, J. M. et al. Global declines in oceanic nitrification rates as a consequence of ocean acidification. Proc. Natl Acad. Sci. USA 108, 208–213 (2011).

    Article  CAS  Google Scholar 

  2. Freing, A., Wallace, D. W. R. & Bange, H. W. Global oceanic production of nitrous oxide. Phil. Trans. R. Soc. B 367, 1245–1255 (2012).

    Article  CAS  Google Scholar 

  3. Caldeira, K. & Wickett, M. E. Oceanography: anthropogenic carbon and ocean pH. Nature 425, 365–365 (2003).

    Article  CAS  Google Scholar 

  4. Orr, J. C. et al. Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms. Nature 437, 681–686 (2005).

    Article  CAS  Google Scholar 

  5. Kump, L. R., Bralower, T. J. & Ridgwell, A. Ocean acidification in deep time. Oceanography 22, 94–107 (2009).

    Article  Google Scholar 

  6. Pearson, P. N. & Palmer, M. R. Atmospheric carbon dioxide concentrations over the past 60 million years. Nature 406, 695–699 (2000).

    Article  CAS  Google Scholar 

  7. Codispoti, L. A. Interesting times for marine N2O. Science 327, 1339–1340 (2010).

    Article  CAS  Google Scholar 

  8. Breider, F., Yoshikawa, C., Abe, H., Toyoda, S. & Yoshida, N. Origin and fluxes of nitrous oxide along a latitudinal transect in western North Pacific: controls and regional significance. Glob. Biogeochem. Cycles 29, 1014–1027 (2015).

    Article  CAS  Google Scholar 

  9. IPCC Climate Change 2007: The Physical Science Basis (eds Solomon, S. et al.) (Cambridge Univ. Press, 2007).

  10. Frame, C. H., Lau, E., Nolan, E. J., Goepfert, T. J. & Lehmann, M. F. Acidification enhances hybrid N2O production associated with aquatic ammonia-oxidizing microorganisms. Front. Microbiol. 7, 2104 (2017).

    Article  Google Scholar 

  11. Rees, A. P., Brown, I. J., Jayakumar, A. & Ward, B. B. The inhibition of N2O production by ocean acidification in cold temperate and polar waters. Deep Sea Res. Pt II 127, 93–101 (2016).

    Article  CAS  Google Scholar 

  12. Honda, M. C. et al. Comparison of carbon cycle between the western Pacific subarctic and subtropical time-series stations: highlights of the K2S1 project. J. Oceanogr. 73, 647–667 (2017).

    Article  CAS  Google Scholar 

  13. Cedervall, P., Hooper, A. B. & Wilmot, C. M. Structural studies of hydroxylamine oxidoreductase reveal a unique heme cofactor and a previously unidentified interaction partner. Biochemistry 52, 6211–6218 (2013).

    Article  CAS  Google Scholar 

  14. Fernández, M. L., Estrin, D. A. & Bari, S. E. Theoretical insight into the hydroxylamine oxidoreductase mechanism. J. Inorg. Biochem. 102, 1523–1530 (2008).

    Article  Google Scholar 

  15. Shiro, Y. Structure and function of bacterial nitric oxide reductases: nitric oxide reductase, anaerobic enzymes. Biochim. Biophys. Acta 1817, 1907–1913 (2012).

    Article  CAS  Google Scholar 

  16. Hino, T. et al. Structural basis of biological N2O generation by bacterial nitric oxide reductase. Science 330, 1666–1670 (2010).

    Article  CAS  Google Scholar 

  17. Yang, H., Gandhi, H., Ostrom, N. & Hegg, E. L. Isotopic fractionation by a fungal P450 nitric oxide reductase during the production of N2O. Environ. Sci. Technol. 48, 10707–10715 (2014).

    Article  CAS  Google Scholar 

  18. Lehnert, N., Praneeth, V. K. K. & Paulat, F. Electronic structure of iron(II)–porphyrin nitroxyl complexes: molecular mechanism of fungal nitric oxide reductase (P450nor). J. Comput. Chem. 27, 1338–1351 (2006).

    Article  CAS  Google Scholar 

  19. Hatzenpichler, R. Diversity, physiology, and niche differentiation of ammonia-oxidizing Archaea. Appl. Environ. Microbiol. 78, 7501–7510 (2012).

    Article  CAS  Google Scholar 

  20. Fehling, C. & Friedrichs, G. Dimerization of HNO in aqueous solution: an interplay of solvation effects, fast acid–base equilibria, and intramolecular hydrogen bonding? J. Am. Chem. Soc. 133, 17912–17922 (2011).

    Article  CAS  Google Scholar 

  21. Toyoda, S., Yoshida, N. & Koba, K. Isotopocule analysis of biologically produced nitrous oxide in various environments. Mass Spectrom. Rev. 36, 135–160 (2017).

    Article  CAS  Google Scholar 

  22. Zhang, Y. Computational investigations of HNO in biology. J. Inorg. Biochem. 118, 191–200 (2013).

    Article  CAS  Google Scholar 

  23. Caranto, J. D. & Lancaster, K. M. Nitric oxide is an obligate bacterial nitrification intermediate produced by hydroxylamine oxidoreductase. Proc. Natl Acad. Sci. USA 114, 8217–8222 (2017).

    Article  CAS  Google Scholar 

  24. Bartberger, M. D., Fukuto, J. M. & Houk, K. N. On the acidity and reactivity of HNO in aqueous solution and biological systems. Proc. Natl Acad. Sci. USA 98, 2194–2198 (2001).

    Article  CAS  Google Scholar 

  25. Krulwich, T. A., Sachs, G. & Padan, E. Molecular aspects of bacterial pH sensing and homeostasis. Nat. Rev. Microbiol. 9, 330–343 (2011).

    Article  CAS  Google Scholar 

  26. Slonczewski, J. L., Fujisawa, M., Dopson, M. & Krulwich, T. A. in Advances in Microbial Physiology Vol. 55 (ed. Poole, R. K.) 1–79 (Academic, 2009).

  27. Wakita, M. et al. Ocean acidification from 1997 to 2011 in the subarctic western North Pacific Ocean. Biogeosciences 10, 7817–7827 (2013).

    Article  Google Scholar 

  28. Wilks, J. C. & Slonczewski, J. L. pH of the cytoplasm and periplasm of Escherichia coli: rapid measurement by green fluorescent protein fluorimetry. J. Bacteriol. 189, 5601–5607 (2007).

    Article  CAS  Google Scholar 

  29. Ishii, M. et al. Ocean acidification off the south coast of Japan: a result from time series observations of CO2 parameters from 1994 to 2008. J. Geophys. Res. Oceans 116, C06022 (2011).

    Google Scholar 

  30. Schlitzer, R. Ocean Data View v.5.1.7 (Alfred Wegener Institute, 2019);

  31. Riebesell, U., Fabry, V. J., Hansson, L. & Gattuso, J.-P. (eds) Guide to Best Practices for Ocean Acidification Research and Data Reporting (European Commission, 2010).

  32. Gattuso, J.-P. & Lavigne, H. Technical Note: approaches and software tools to investigate the impact of ocean acidification. Biogeosciences 6, 2121–2133 (2009).

    Article  CAS  Google Scholar 

  33. Schulz, K. G., Barcelos e Ramos, J., Zeebe, R. E. & Riebesell, U. CO2 perturbation experiments: similarities and differences between dissolved inorganic carbon and total alkalinity manipulations. Biogeosciences 6, 2145–2153 (2009).

    Article  CAS  Google Scholar 

  34. Berg, I. A., Kockelkorn, D., Buckel, W. & Fuchs, G. A 3-hydroxypropionate/4-hydroxybutyrate autotrophic carbon dioxide assimilation pathway in Archaea. Science 318, 1782–1786 (2007).

    Article  CAS  Google Scholar 

  35. Badger, M. R. & Bek, E. J. Multiple Rubisco forms in proteobacteria: their functional significance in relation to CO2 acquisition by the CBB cycle. J. Exp. Bot. 59, 1525–1541 (2008).

    Article  CAS  Google Scholar 

  36. Kock, A. & Bange, H. W. Nitrite removal improves hydroxylamine analysis in aqueous solution by conversion with iron(III). Environ. Chem. 10, 64–71 (2013).

    Article  CAS  Google Scholar 

  37. Frame, C. H. & Casciotti, K. L. Biogeochemical controls and isotopic signatures of nitrous oxide production by a marine ammonia-oxidizing bacterium. Biogeosciences 7, 2695–2709 (2010).

    Article  CAS  Google Scholar 

  38. Santoro, A. E., Buchwald, C., McIlvin, M. R. & Casciotti, K. L. Isotopic signature of N2O produced by marine ammonia-oxidizing Archaea. Science 333, 1282–1285 (2011).

    Article  CAS  Google Scholar 

  39. Yamagishi, H. et al. Role of nitrification and denitrification on the nitrous oxide cycle in the eastern tropical North Pacific and Gulf of California. J. Geophys. Res. Biogeosci. 112, G02015 (2007).

    Article  Google Scholar 

  40. Toyoda, S. & Yoshida, N. Determination of nitrogen isotopomers of nitrous oxide on a modified isotope ratio mass spectrometer. Anal. Chem. 71, 4711–4718 (1999).

    Article  CAS  Google Scholar 

  41. Toyoda, S., Mutobe, H., Yamagishi, H., Yoshida, N. & Tanji, Y. Fractionation of N2O isotopomers during production by denitrifier. Soil Biol. Biochem. 37, 1535–1545 (2005).

    Article  CAS  Google Scholar 

  42. Sigman, D. M. et al. A bacterial method for the nitrogen isotopic analysis of nitrate in seawater and freshwater. Anal. Chem. 73, 4145–4153 (2001).

    Article  CAS  Google Scholar 

  43. Peng, X. et al. Revisiting nitrification in the Eastern Tropical South Pacific: a focus on controls. Geophys. Res. Oceans 121, 1667–1684 (2016).

    Article  CAS  Google Scholar 

  44. Charpentier, J., Farias, L., Yoshida, N., Boontanon, N. & Raimbault, P. Nitrous oxide distribution and its origin in the central and eastern South Pacific Subtropical Gyre. Biogeosciences 4, 729–741 (2007).

    Article  CAS  Google Scholar 

Download references


We thank the captain, officers, crew, scientists and technicians for their assistance during the KS-16-8 and YK16-16 cruises and M. C. Honda, PI of the MR13-04 cruise. This project was financially supported by Kakenhi grants (project nos 23224013, 15H05822, 15H05471 and 17H06105) of the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT) and the Swiss National Science Foundation (project no. PBNEP2-142954).

Author information

Authors and Affiliations



F.B., C.Y., A.M. and S.T. conceived this study, designed and executed the experiments, analysed the results and wrote the paper. M.W. calculated pH values from DIC and total alkalinity for all cruises. Y.M. measured δ15NO3 values to estimate nitrification rates. S.K., T.F. and N.H. contributed to the organization of the sampling campaigns. All authors contributed to the interpretation of the results and the preparation of the manuscript.

Corresponding author

Correspondence to Florian Breider.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Peer review information Nature Climate Change thanks Hermann Bange, Shuh-Ji Kao and Brian Popp for their contribution to the peer review of this work.

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Tables 1 and 2 and Figs. 1–4.

Reporting Summary

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Breider, F., Yoshikawa, C., Makabe, A. et al. Response of N2O production rate to ocean acidification in the western North Pacific. Nat. Clim. Chang. 9, 954–958 (2019).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


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