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.

Reduction of soil carbon formation by tropospheric ozone under increased carbon dioxide levels


In the Northern Hemisphere, ozone levels in the troposphere have increased by 35 per cent over the past century1, with detrimental impacts on forest2,3 and agricultural4 productivity, even when forest productivity has been stimulated by increased carbon dioxide levels5. In addition to reducing productivity, increased tropospheric ozone levels could alter terrestrial carbon cycling by lowering the quantity and quality of carbon inputs to soils. However, the influence of elevated ozone levels on soil carbon formation and decomposition are unknown. Here we examine the effects of elevated ozone levels on the formation rates of total and decay-resistant acid-insoluble soil carbon under conditions of elevated carbon dioxide levels in experimental aspen (Populus tremuloides) stands and mixed aspen–birch (Betula papyrifera) stands. With ambient concentrations of ozone and carbon dioxide both raised by 50 per cent, we find that the formation rates of total and acid-insoluble soil carbon are reduced by 50 per cent relative to the amounts entering the soil when the forests were exposed to increased carbon dioxide alone. Our results suggest that, in a world with elevated atmospheric carbon dioxide concentrations, global-scale reductions in plant productivity due to elevated ozone levels will also lower soil carbon formation rates significantly.

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

Figure 1: Total carbon incorporated into soils during 4 yr of exposure to elevated O3 + CO2 and elevated CO2.
Figure 2: Carbon incorporated into the stable acid-insoluble fraction of soils during 4 yr of exposure to elevated O3 + CO2 and elevated CO2.


  1. IPCC Climate Change 2001: Technical Summary (Report of the Intergovernmental Panel on Climate Change, IPCC Secretariat, Geneva, 2001).

  2. Gregg, J. W., Jones, C. G. & Dawson, T. E. Urbanization effects on tree growth in the vicinity of New York City. Nature 424, 183–187 (2003)

    Article  CAS  Google Scholar 

  3. McLaughlin, S. B. & Downing, D. J. Interactive effects of ambient ozone and climate measured on growth of mature forest trees. Nature 374, 252–254 (1995)

    Article  CAS  Google Scholar 

  4. Chameides, W. L., Kasibhatla, P. S., Yienger, J. & Levy, H. I. Growth of continental-scale metro-agro-plexes, regional ozone pollution, and world food production. Science 264, 74–77 (1994)

    Article  CAS  Google Scholar 

  5. Percy, K. E. et al. Altered performance of forest pests under CO2- and O3-enriched atmospheres. Nature 420, 403–407 (2002)

    Article  CAS  Google Scholar 

  6. Latest Findings on National Air Quality: 2002 Status and Trends (US Environmental Protection Agency).

  7. Findlay, S., Carreiro, M., Krischik, V. & Jones, C. G. Effects of damage to living plants on leaf litter quality. Ecol. Appl. 6, 269–275 (1996)

    Article  Google Scholar 

  8. Coleman, M. D., Dickson, R. E., Isebrands, J. G. & Karnosky, D. F. Carbon allocation and partitioning in aspen clones varying in sensitivity to tropospheric ozone. Tree Physiol. 15, 593–604 (1995)

    Article  CAS  Google Scholar 

  9. Andersen, C. P. Source-sink balance and carbon allocation below ground in plants exposed to ozone. New Phytol. 157, 213–228 (2003)

    Article  CAS  Google Scholar 

  10. King, J. S. et al. Fine-root biomass and fluxes of soil carbon in young stands of paper birch and trembling aspen as affected by elevated atmospheric CO2 and tropospheric O3 . Oecologia 128, 237–250 (2001)

    Article  CAS  Google Scholar 

  11. Dickson, R. E. et al. Forest Atmosphere Carbon Transfer and Storage (FACTS-II)—The Aspen Free-air CO2 and O3 Enrichment (FACE) Project: An Overview (Technical Report NC-214, USDA, Washington DC, 2000)

    Book  Google Scholar 

  12. Leavitt, S. W., Follett, R. F. & Paul, E. A. Estimation of slow- and fast-cycling soil organic carbon pools from 6N HCl hydrolysis. Radiocarbon 38, 231–239 (1996)

    Article  CAS  Google Scholar 

  13. Paul, E. A. et al. Radiocarbon dating for determination of soil organic matter pool sizes and dynamics. Soil Sci. Soc. Am. J. 61, 1058–1067 (1997)

    Article  CAS  Google Scholar 

  14. Phillips, R., Zak, D. R., Holmes, W. E. & White, D. C. Microbial community composition and function beneath temperate trees exposed to elevated atmospheric carbon dioxide and ozone. Oecologia 131, 236–244 (2002)

    Article  Google Scholar 

  15. Larson, J., Zak, D. R. & Sinsabaugh, R. L. Extracellular enzyme activity beneath temperate trees growing under elevated carbon dioxide and ozone. Soil Sci. Soc. Am. J. 66, 1848–1856 (2002)

    Article  CAS  Google Scholar 

Download references


This research was supported by the US Department of Energy's Office of Science (BER: Program for Ecosystem Research and National Institute for Global Environmental Change), the USDA Forest Service (Northern Global Change and North Central Research Station), the National Science Foundation (DEB, DBI/MRI), and the USDA Natural Research Initiatives Competitive Grants Program. G. Hendry, K. Lewin, J. Nagey, D. Karnosky and J. Sober have been instrumental in the successful implementation of this long-term field experiment.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Wendy M. Loya.

Ethics declarations

Competing interests

The authors declare that they have no competing financial interests.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Loya, W., Pregitzer, K., Karberg, N. et al. Reduction of soil carbon formation by tropospheric ozone under increased carbon dioxide levels. Nature 425, 705–707 (2003).

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI:

This article is cited by


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.


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