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:

Sustained losses of bioavailable nitrogen from montane tropical forests

Nature Geoscience volume 5, pages 123–126 (2012)Cite this article

Subjects

Abstract

Tropical forests account for one third of terrestrial primary production and contribute significantly to the land carbon sink1,2. The future of this sink relies critically on forest interactions with nutrient cycles3,4,5. Humid montane tropical forests are often thought to be rich in phosphorus, but to contain low levels of bioavailable nitrogen6. Here, we examine the concentration of dissolved nitrogen compounds and the isotopic composition of nitrate in streams in six well-characterized and phosphorus-rich montane forests7 in Costa Rica, and in 55 montane forests across Central America and the Caribbean, using data collected between 1990 and 2008. We found high levels of nitrate in these streams, indicative of large losses of bioavailable nitrogen from these forests. We detected no trend in the concentration and isotopic signature of nitrate over the measurement period, implying that high levels of export are neither recent nor episodic. An analysis of the oxygen isotopic signature of stream nitrate showed that exports are sourced from the plant–soil system, rather than from atmospheric deposition that bypasses forest biota. Our findings indicate that nitrogen-rich conditions can develop irrespective of phosphorus availability at the ecosystem scale. We suggest that nitrogen availability may not limit plant growth, or its response to increasing atmospheric carbon dioxide levels, in many montane tropical forests.

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: Nitrogen concentrations in watershed streams of old-growth forests across neotropical mountains.
Figure 2: Concentrations, isotope signatures and sources of nitrate in watershed streams of the Maritza Biological Station over time.
Figure 3: Sources of stream nitrate in old-growth neotropical forests.

Similar content being viewed by others

References

  1. Field, C., Behrenfeld, M., Randerson, J. & Falkowski, P. Primary production of the biosphere: Integrating terrestrial and oceanic components. Science 281, 237–240 (1998).

    Article  Google Scholar 

  2. Phillips, O. et al. Changes in the carbon balance of tropical forests: Evidence from long-term plots. Science 282, 439–442 (1998).

    Article  Google Scholar 

  3. Vitousek, P. Nutrient Cycling and Limitation, Hawai’i as a Model System (Princeton Univ. Press, 2004).

    Google Scholar 

  4. Hedin, L. O., Brookshire, E. N. J., Menge, D. N. L. & Barron, A. R. The nitrogen paradox in tropical forest ecosystems. Annu. Rev. Ecol. Evol. Syst. 40, 613–635 (2009).

    Article  Google Scholar 

  5. Barron, A. et al. Molybdenum limitation of asymbiotic nitrogen fixation in tropical forest soils. Nature Geosci. 2, 42–45 (2009).

    Article  Google Scholar 

  6. Tanner, E., Vitousek, P. & Cuevas, E. Experimental investigation of nutrient limitation of forest growth on wet tropical mountains. Ecology 79, 10–22 (1998).

    Article  Google Scholar 

  7. Newbold, J. D., Sweeney, B., Jackson, J. & Kaplan, L. Concentrations and export of solutes from 6 mountain streams in northwestern Costa Rica. J. North Am. Benth. Soc. 14, 21–37 (1995).

    Article  Google Scholar 

  8. Porder, S., Vitousek, P., Chadwick, O., Chamberlain, C. & Hilley, G. Uplift, erosion, and phosphorus limitation in terrestrial ecosystems. Ecosystems 10, 158–170 (2007).

    Article  Google Scholar 

  9. LeBauer, D. & Treseder, K. Nitrogen limitation of net primary productivity in terrestrial ecosystems is globally distributed. Ecology 89, 371–379 (2008).

    Article  Google Scholar 

  10. Templer, P., Silver, W., Pett-Ridge, J., DeAngelis, K. & Firestone, M. Plant and microbial controls on nitrogen retention and loss in a humid tropical forest. Ecology 89, 3030–3040 (2008).

    Article  Google Scholar 

  11. Menge, D. N. L., Pacala, S. W. & Hedin, L. O. Emergence and maintenance of nutrient limitation over multiple timescales in terrestrial ecosystems. Am. Nat. 173, 164–175 (2009).

    Article  Google Scholar 

  12. Hedin, L. O., Vitousek, P. M. & Matson, P. A. Nutrient losses over four million years of tropical forest development. Ecology 84, 2231–2255 (2003).

    Article  Google Scholar 

  13. Neill, C., Deegan, L., Thomas, S. & Cerri, C. Deforestation for pasture alters nitrogen and phosphorus in small Amazonian Streams. Ecol. Appl. 11, 1817–1828 (2001).

    Article  Google Scholar 

  14. Lewis, W., Melack, J., McDowell, W., McClain, M. & Richey, J. Nitrogen yields from undisturbed watersheds in the Americas. Biogeochemistry 46, 149–162 (1999).

    Google Scholar 

  15. Aber, J. et al. Is nitrogen deposition altering the nitrogen status of Northeastern forests? BioScience 53, 375–389 (2003).

    Article  Google Scholar 

  16. Perakis, S. S. & Hedin, L. O. Nitrogen loss from unpolluted South American forests mainly via dissolved organic compounds. Nature 415, 416–419 (2002).

    Article  Google Scholar 

  17. Dentener, F. et al. Nitrogen and sulfur deposition on regional and global scales: A multimodel evaluation. Glob. Biogeochem. Cycles 20, GB4003 (2006).

    Article  Google Scholar 

  18. Goodale, et al. Unusual seasonal patterns and inferred processes of nitrogen retention in forested headwaters of the Upper Susquehanna River. Biogeochemistry 93, 197–218 (2009).

    Article  Google Scholar 

  19. Davidson, E. et al. Recuperation of nitrogen cycling in Amazonian forests following agricultural abandonment. Nature 447, 995–998 (2007).

    Article  Google Scholar 

  20. Sigman, D. et al. Coupled nitrogen and oxygen isotope measurements of nitrate along the eastern North Pacific margin. Glob. Biogeochem. Cycles 19, GB4022 (2005).

    Article  Google Scholar 

  21. Hastings, M., Jarvis, J. & Steig, E. Anthropogenic impacts on nitrogen isotopes of ice-core nitrate. Science 324, 1288–1288 (2009).

    Article  Google Scholar 

  22. Trumbore, S., Chadwick, O. & Amundson, R. Rapid exchange between soil carbon and atmospheric carbon dioxide driven by temperature change. Science 272, 393–396 (1996).

    Article  Google Scholar 

  23. Durka, W., Schulze, E., Gebauer, G. & Voerkelius, S. Effects of forest decline on uptake and leaching of deposited nitrate determined from 15N and 18O measurements. Nature 372, 765–767 (1994).

    Article  Google Scholar 

  24. Barnes, R. T., Raymond, P. A. & Casciotti, K. L. Dual isotope analyses indicate efficient processing of atmospheric nitrate by forested watersheds in the northeastern US. Biogeochemistry 90, 15–27 (2008).

    Article  Google Scholar 

  25. Houlton, B., Sigman, D. & Hedin, L. Isotopic evidence for large gaseous nitrogen losses from tropical rainforests. Proc. Natl. Acad. Sci. USA 103, 8745–8750 (2006).

    Article  Google Scholar 

  26. Reed, S., Cleveland, C. & Townsend, A. Tree species control rates of free-living nitrogen fixation in a tropical rainforest. Ecology 89, 2924–2934 (2008).

    Article  Google Scholar 

  27. Barron, A. R., Purves, D. W. & Hedin, L. O. Facultative nitrogen fixation by canopy legumes in a lowland tropical forest. Oecologia 165, 511–520 (2010).

    Article  Google Scholar 

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

    Article  Google Scholar 

  29. Casciotti, K., Sigman, D., Hastings, M., Bohlke, J. & Hilkert, A. Measurement of the oxygen isotopic composition of nitrate in seawater and freshwater using the denitrifier method. Anal. Chem. 74, 4905–4912 (2002).

    Article  Google Scholar 

Download references

Acknowledgements

We thank R. Morales for field assistance in Costa Rica and S. A. Thomas for supporting travel to Trinidad. This work was supported by grants from the A.W. Mellon Foundation, the NSF (DEB-0614116) and NOAA to L.O.H. Financial support for meteorological and chemical data from Estación Maritza came from the NSF (BSR-90078445, DEB 9904047 and DEB 0516516) and from the research endowments of the Stroud Water Research Center. Maritza samples from 1999 to 2001 were provided by L. A. Kaplan.

Author information

Authors and Affiliations

  1. Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey 08544, USA

    E. N. Jack Brookshire & Lars O. Hedin

  2. Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, Montana 59717, USA

    E. N. Jack Brookshire

  3. Stroud Water Research Center, Avondale, Pennsylvania 19311, USA

    J. Denis Newbold & John K. Jackson

  4. Department of Geosciences, Princeton University, Princeton, New Jersey 08544, USA

    Daniel M. Sigman

Authors
  1. E. N. Jack Brookshire
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Lars O. Hedin
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. J. Denis Newbold
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Daniel M. Sigman
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. John K. Jackson
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

E.N.J.B. and L.O.H. conceived of the project, analysed data and wrote the paper. E.N.J.B. conducted field work and isotope analyses. J.D.N., D.M.S. and J.K.J. helped with analysis and writing.

Corresponding author

Correspondence to E. N. Jack Brookshire.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

Supplementary Information (PDF 1034 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Brookshire, E., Hedin, L., Newbold, J. et al. Sustained losses of bioavailable nitrogen from montane tropical forests. Nature Geosci 5, 123–126 (2012). https://doi.org/10.1038/ngeo1372

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/ngeo1372

This article is cited by

Search

Advanced search

Quick links

Nature Briefing Microbiology

Sign up for the Nature Briefing: Microbiology newsletter — what matters in microbiology research, free to your inbox weekly.

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