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.

Confirmation of iron limitation of phytoplankton photosynthesis in the equatorial Pacific Ocean

Abstract

THE eastern equatorial Pacific Ocean is one of only three open-ocean regions where low phytoplankton chlorophyll biomass persists despite perennially high nitrate and phosphate nutrient concentrations1. In 1993, an area within this region was artificially enriched with a single dose of soluble iron to test whether phytoplankton are physiologically prevented from utilizing the available nutrients by the low natural iron concentrations2,3. Although photosynthesis was stimulated4, the observed lack of a bloom or a significant decrease in nutrient concentrations could not be attributed unequivocally to zooplankton grazing5–7, further iron limitation or secondary nutrient limitation2,4. In 1995, a second iron-enrichment experiment (IronEx II) was conducted in which the same total dosage of iron was added, but over eight days8. A massive phytoplankton bloom developed, significantly reducing surface-water nutrient and CO2 concentrations8–10. Here we report in situ measurements of fluorescence during IronEx II, which show that the iron enrichment triggered biophysical alterations of the phytoplankton's photosynthetic apparatus, resulting in increased photosynthetic capacities throughout the experiment and, hence, the observed bloom. These results unequivocally establish physiological limitation of phytoplankton by iron as the cause of the high-nitrate, low-chlorophyll phenomenon in this ocean region.

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

Similar content being viewed by others

References

  1. Martin, J. H. Oceanography 4, 52–55 (1991).

    Article  Google Scholar 

  2. Martin, J. H. et al. Nature 371, 123–129 (1994).

    Article  ADS  CAS  Google Scholar 

  3. Falkowski, P. G. Global Change Biol. 1, 161–163 (1995).

    Article  ADS  Google Scholar 

  4. Kolber, Z. S. et al. Nature 371, 145–149 (1994).

    Article  ADS  CAS  Google Scholar 

  5. Banse, K. Nature 375, 112 (1995).

    Article  ADS  CAS  Google Scholar 

  6. Cullen, J. J. Limnol. Oceanogr. 40, 1336–1343 (1995).

    Article  ADS  CAS  Google Scholar 

  7. Wells, M. L. Nature 368, 295–296 (1994).

    Article  ADS  Google Scholar 

  8. Coale, K. et al. Nature 383, 495–501 (1996).

    Article  ADS  CAS  Google Scholar 

  9. Millero, F. J., Zhu, X. R. & Steinberg, P. A. Eos 76, suppl., abstr. OS42M-01 (1996).

  10. Cooper, D. J., Watson, A. J. & Nightingale, P. D. Nature 383, 511–513 (1996).

    Article  ADS  CAS  Google Scholar 

  11. Kolber, Z. & Falkowski, P. G. Limnol. Oceanogr. 38, 1646–1665 (1993).

    Article  ADS  CAS  Google Scholar 

  12. Falkowski, P. G. & Kolber, Z. Aust. J. Plant Physiol. 22, 341–355 (1995).

    Google Scholar 

  13. Cavender-Bares, K. K., Mann, E. & Chisholm, S. W. Nature (submitted).

  14. Vassiliev, I. R. et al. Plant Physiol. 109, 963–972 (1995).

    Article  CAS  Google Scholar 

  15. Greene, R. M., Geider, R. J. & Falkowski, P. G. Limnol. Oceanogr. 36, 1772–1782 (1991).

    Article  ADS  CAS  Google Scholar 

  16. Greene, R. M., Geider, R. J., Kolber, Z. & Falkowski, P. G. Plant Physiol. 100, 565–575 (1992).

    Article  CAS  Google Scholar 

  17. Banse, K. Limnol. Oceanogr. 35, 772–775 (1990).

    Article  ADS  CAS  Google Scholar 

  18. Frost, B. W. Limnol. Oceanogr. 36, 1616–1630 (1991).

    Article  ADS  Google Scholar 

  19. Banse, K. in Primary Productivity and Biogeochemical Cycles in the Sea (eds Falkowski, P. G. & Woodhead, A. D.) 409–440 (Plenum, New York, 1992).

    Book  Google Scholar 

  20. Falkowski, P. G. Global Change Biol. 1, 161–163 (1995).

    Article  ADS  Google Scholar 

  21. Lehman, J. T. Limnol. Oceanogr. 36, 1546–1554 (1991).

    Article  ADS  CAS  Google Scholar 

  22. Goldman, J. C. in Primary Productivity in the Sea (ed. Falkowski, P. G.) 179–194 (Plenum, New York, 1980).

    Book  Google Scholar 

  23. Kolber, Z. & Falkowski, P. G. Plant Physiol. 88, 72–79 (1988).

    Article  Google Scholar 

  24. Tilman, D., Wedin, D. & Knops, J. Nature 379, 718–720 (1996).

    Article  ADS  CAS  Google Scholar 

  25. Paine, R. T. in Readings in Aquatic Ecology (eds Ford, R. F. & Hazen, W. E.) 276–287 (Saunders, Philadelphia, 1972).

    Google Scholar 

  26. Carpenter, S. R. et al. Science 269, 324–327 (1995).

    Article  ADS  CAS  Google Scholar 

  27. Martin, J. H., Gordon, R. M., Fitzwater, S. & Broenkow, W. W. Deep-Sea Res. 36, 649–680 (1989).

    Article  ADS  CAS  Google Scholar 

  28. Berger, W. H. & Wefer, G. Limnol. Oceanogr. 36, 1899–1918 (1991).

    Article  ADS  CAS  Google Scholar 

  29. Murray, R. W. et al. Global Biogeochem. Cycles 9, 1899–1918 (1991).

    Google Scholar 

  30. Sarmiento, J. L. & Orr, J. C. Limnol. Oceanogr. 36, 1928–1950 (1991).

    Article  ADS  CAS  Google Scholar 

  31. Kumar, N. et al. Nature 378, 675–680 (1995).

    Article  ADS  CAS  Google Scholar 

  32. Aiken, J. & Bellan, I. in Light and Life in the Sea (eds Herring, P. J., Campbell, A. K., Whitfield, M. & Maddock, L.) 39–59 (Cambridge University Press, Cambridge, 1990).

    Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

Behrenfeld, M., Bale, A., Kolber, Z. et al. Confirmation of iron limitation of phytoplankton photosynthesis in the equatorial Pacific Ocean. Nature 383, 508–511 (1996). https://doi.org/10.1038/383508a0

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/383508a0

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