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.

Net production of oxygen in the subtropical ocean

Abstract

The question of whether the plankton communities in low-nutrient regions of the ocean, comprising 80% of the global ocean surface area, are net producers or consumers of oxygen and fixed carbon is a key uncertainty in the global carbon cycle1,2. Direct measurements in bottle experiments indicate net oxygen consumption in the sunlit zone3,4,5,6, whereas geochemical evidence suggests that the upper ocean is a net source of oxygen2. One possible resolution to this conflict is that primary production in the gyres is episodic1,2,6 and thus difficult to observe: in this model, oligotrophic regions would be net consumers of oxygen during most of the year, but strong, brief events with high primary production rates might produce enough fixed carbon and dissolved oxygen to yield net production as an average over the annual cycle. Here we examine the balance of oxygen production over three years at sites in the North and South Pacific subtropical gyres using the new technique of oxygen sensors deployed on profiling floats. We find that mixing events during early winter homogenize the upper water column and cause low oxygen concentrations. Oxygen then increases below the mixed layer at a nearly constant rate that is similar to independent measures of net community production. This continuous oxygen increase is consistent with an ecosystem that is a net producer of fixed carbon (net autotrophic) throughout the year, with episodic events not required to sustain positive oxygen production.

Your institute does not have access to this article

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Figure 1: Profile locations and oxygen concentration in the subtropical Pacific.
Figure 2: Contours of the evolution of oxygen concentration and density in the upper 200 m.
Figure 3: Oxygen concentrations in the SOM versus time.
Figure 4: Plot of NCP versus depth.

References

  1. del Giorgio, P. A. & Duarte, C. M. Respiration in the open ocean. Nature 420, 379–384 (2002)

    CAS  ADS  Article  Google Scholar 

  2. Karl, D. M., Laws, E. A., Morris, P., Williams, P. J., le B & Emerson, S. Metabolic balance in the open sea. Nature 426, 32 (2003)

    CAS  ADS  Article  Google Scholar 

  3. del Giorgio, P. A., Cole, J. J. & Cimbleris, A. Respiration rates in bacteria exceed phytoplankton production in unproductive aquatic systems. Nature 385, 148–151 (1997)

    CAS  ADS  Article  Google Scholar 

  4. Duarte, C. M. & Agusti, S. The CO2 balance of unproductive aquatic ecosystems. Science 281, 234–236 (1998)

    CAS  ADS  Article  Google Scholar 

  5. Duarte, C. M., Agusti, S., del Giorgio, P. A. & Cole, J. J. Regional carbon imbalances in the oceans. Science 284, 173–174 (1999)

    Google Scholar 

  6. Williams, P. J., le B, Morris, P. J. & Karl, D. M. Net community production and metabolic balance at the oligotrophic ocean site, station ALOHA. Deep-Sea Res. I 51, 1563–1578 (2004)

    Article  Google Scholar 

  7. Williams, P. J., le B & Bowers, D. G. Regional carbon imbalances in the oceans. Science 284, 173–174 (1999)

    Article  Google Scholar 

  8. Roemmich, D., Riser, S., Davis, R. & Desaubies, Y. Autonomous profiling floats: workhorse for broad-scale observations. Mar. Technol. Soc. J. 38, 21–29 (2004)

    Article  Google Scholar 

  9. Roemmich, D. et al. in Observing the Oceans in the 21st Century (eds Koblinsky, K. & Smith, N.) 248–258 (Australian Bureau of Meteorology, Melbourne, Australia, 2001)

    Google Scholar 

  10. Kortzinger, A., Schimanski, J., Send, U. & Wallace, D. The ocean takes a deep breath. Science 306, 1337 (2004)

    Article  Google Scholar 

  11. Johnson, K. S., Needoba, J. A., Riser, S. C. & Showers, W. J. Chemical sensor networks for the aquatic environment. Chem. Rev. 107, 623–640 (2007)

    CAS  Article  Google Scholar 

  12. Schulenberger, E. & Reid, J. L. The Pacific shallow oxygen maximum, deep chlorophyll maximum, and primary productivity reconsidered. Deep-Sea Res. A 28, 901–919 (1981)

    ADS  Article  Google Scholar 

  13. Anderson, L. A. On the hydrogen and oxygen content of marine phytoplankton. Deep-Sea Res. I 42, 1675–1680 (1995)

    CAS  Article  Google Scholar 

  14. Letelier, R. M., Karl, D. M., Abbott, M. R. & Bidigare, R. R. Role of late winter mesoscale events in the biogeochemical variability of the upper water column of the North Pacific Subtropical Gyre. J. Geophys. Res. 105, 28723–28739 (2000)

    CAS  ADS  Article  Google Scholar 

  15. Keeling, C. D., Brix, H. & Gruber, N. Seasonal and long-term dynamics of the upper ocean carbon cycle at Station ALOHA near Hawaii. Glob. Biogeochem. Cycles 18 doi: 10.1029/2004GB002227 (2004)

  16. Behrenfeld, M. J., Boss, E., Siegel, D. A. & Shea, D. M. Carbon-based ocean productivity and phytoplankton physiology from space. Glob. Biogeochem. Cycles 19 doi: 10.1029/2004GB002299 (2005)

  17. Scharek, R., Tupas, L. M. & Karl, D. M. Diatom fluxes to the deep sea in the oligotrophic North Pacific gyre at Station Aloha. Mar. Ecol. Prog. Ser. 182, 55–67 (1999)

    ADS  Article  Google Scholar 

  18. Emerson, S., Stump, C., Johnson, B. & Karl, D. M. In situ determination of oxygen and nitrogen dynamics in the upper ocean. Deep-Sea Res. I 49, 941–952 (2002)

    CAS  Article  Google Scholar 

  19. Schlitzer, R. Ocean Data View 〈http://odv.awi.de〉 (2006)

  20. Weiss, R. F. The solubility of nitrogen, oxygen and argon in water and seawater. Deep-Sea Res. A 17, 721–735 (1970)

    CAS  Google Scholar 

Download references

Acknowledgements

We thank N. Larson for producing the oxygen sensors; D. Swift for his essential contributions to this effort; and the Hawaii Ocean Time-series participants for making dissolved oxygen data available. Research at the University of Washington was supported through the US Argo Program by the National Oceanographic and Atmospheric Administration and by the US Office of Naval Research through the National Ocean Partnership Program. Research at Monterey Bay Aquarium Research Institute was supported by a grant from the David and Lucile Packard Foundation and by the National Science Foundation.

Author Contributions S.C.R. originated the idea of putting oxygen sensors on profiling floats, and directed the construction and deployment of the floats as part of the international Argo project. K.S.J. performed the data analysis. Both authors contributed to the writing of the manuscript.

Author information

Authors and Affiliations

Authors

Corresponding authors

Correspondence to Stephen C. Riser or Kenneth S. Johnson.

Additional information

All float data are available from the global Argo data center at ftp://usgodael.fnmoc.navy.mil/pub/outgoing/argo/.

Supplementary information

Supplementary Figures

The file contains Supplementary Figures 1-2 with Legends. (PDF 112 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Riser, S., Johnson, K. Net production of oxygen in the subtropical ocean. Nature 451, 323–325 (2008). https://doi.org/10.1038/nature06441

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature06441

Further reading

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