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Nitrogen limitation of microbial decomposition in a grassland under elevated CO2


Carbon accumulation in the terrestrial biosphere could partially offset the effects of anthropogenic CO2 emissions on atmospheric CO2 (refs 1, 2). The net impact of increased CO2 on the carbon balance of terrestrial ecosystems is unclear, however, because elevated CO2 effects on carbon input to soils and plant use of water and nutrients often have contrasting effects on microbial processes3,4,5. Here we show suppression of microbial decomposition in an annual grassland after continuous exposure to increased CO2 for five growing seasons. The increased CO2 enhanced plant nitrogen uptake, microbial biomass carbon, and available carbon for microbes. But it reduced available soil nitrogen, exacerbated nitrogen constraints on microbes, and reduced microbial respiration per unit biomass. These results indicate that increased CO2 can alter the interaction between plants and microbes in favour of plant utilization of nitrogen, thereby slowing microbial decomposition and increasing ecosystem carbon accumulation.

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Figure 1: Below-ground respiration.
Figure 2: Extractable inorganic soil N over the growing season.
Figure 3: Microbial biomass carbon (a), nitrogen (b) and C:N ratios (c) in ambient (open bars) and elevated (filled bars) CO2.
Figure 4: 15N distribution.


  1. Schimel, D. et al. in Climate Change 1995: The Science of Climate Change (eds Houghton, J. T. et al.) 65–131 (Cambridge Univ. Press, Cambridge, 1996).

    Google Scholar 

  2. DeLucia, E. H. et al. Net primary production of a forest ecosystem with experimental CO2 enrichment. Science 284, 1177–1179 (1999).

    Article  ADS  CAS  Google Scholar 

  3. Diaz, S., Grime, J. P., Harris, J. & McPherson, E. Evidence of a feedback mechanism limiting plant response to elevated carbon dioxide. Nature 364, 616–617 ( 1993).

    Article  ADS  CAS  Google Scholar 

  4. Zak, D. R. et al. Elevated atmospheric CO2 and feedback between carbon and nitrogen cycles. Plant Soil 151, 105 –117 (1993).

    Article  CAS  Google Scholar 

  5. Jones, T. H. et al. Impacts of rising atmospheric carbon dioxide on model terrestrial ecosystems. Science 280, 441– 443 (1998).

    Article  ADS  CAS  Google Scholar 

  6. Schimel, D. S. Terrestrial ecosystems and the carbon cycles. Glob. Change Biol. 1, 77–91 (1995 ).

    Article  ADS  Google Scholar 

  7. Raich, J. W. & Potter, C. S. Global patterns of carbon dioxide emissions from soils. Glob. Biogeochem. Cycles 9, 23–36 (1995).

    Article  ADS  CAS  Google Scholar 

  8. Jackson, R. B., Sala, O. E., Field, C. B. & Mooney, H. A. CO2 alters water use, carbon gain, and yield for the dominant species in a natural grassland. Oecologia 98, 257 –262 (1994).

    Article  ADS  CAS  Google Scholar 

  9. Rice, C. W., Garcia, F. O., Hampton, C. O. & Owensby, C. E. Soil microbial response in tallgrass prairie to elevated CO2. Plant Soil 165, 67–74 ( 1994).

    Article  CAS  Google Scholar 

  10. Vitousek, P. M. & Howarth, R. W. Nitrogen limitation on land and in the sea—how can it occur. Biogeochemistry 13, 87–115 ( 1991).

    Article  Google Scholar 

  11. McGuire, A. D., Melillo, J. M. & Joyce, L. A. The role of nitrogen in the response of forest net primary production to elevated atmospheric carbon dioxide. Annu. Rev. Ecol. Syst. 26, 473–503 (1995).

    Article  Google Scholar 

  12. Kaye, J. P. & Hart, S. C. Competition for nitrogen between plants and soil microorganisms. Trends Ecol. Evol. 12, 139–143 (1997).

    Article  CAS  Google Scholar 

  13. Wang, J. G. & Bakken, L. R. Competition for nitrogen during mineralization of plant residues in soil: Microbial response to C and N. Soil Biol. Biochem. 29, 163–170 (1997).

    Article  Google Scholar 

  14. Körner, C. & Arnone, J. A. Responses to elevated carbon dioxide in artificial tropical ecosystems. Science 257, 1672–1675 ( 1992).

    Article  ADS  Google Scholar 

  15. Field, C. B. et al. in Carbon Dioxide and Terrestrial Ecosystems (eds Koch, G. W. & Mooney, H. A.) 121–145 (Academic, San Diego, 1996).

    Book  Google Scholar 

  16. Hungate, B. A. et al. The fate of carbon in grasslands under carbon dioxide enrichment. Nature 388, 576–579 (1997).

    Article  ADS  CAS  Google Scholar 

  17. Luo, Y., Jackson, R. B., Field, C. B. & Mooney, H. A. Elevated CO2 increases belowground respiration in California grasslands. Oecologia 108, 130–137 (1996).

    Article  ADS  Google Scholar 

  18. Lambers, H., Stulen, I. & Van Der Werf, A. Carbon use in root respiration as affected by elevated atmospheric CO2. Plant Soil 187, 251–263 (1996).

    Article  CAS  Google Scholar 

  19. Fitter, A. H. et al. Root production and turnover and carbon budgets of two contrasting grasslands under ambient and elevated atmospheric carbon dioxide concentrations. New Phytol. 137, 247–255 (1997).

    Article  ADS  Google Scholar 

  20. Paterson, E. et al. Effect of elevated CO2 on rhizosphere carbon flow and soil microbial processes. Glob. Change Biol. 3, 363–377 (1997).

    Article  ADS  Google Scholar 

  21. Smith, J. L. & Paul, E. A. in Soil Biochemistry Vol. 6 (eds Bollag, J. & Stotzky, G.) 357– 395 (Marcel Dekker, New York, 1990).

    Google Scholar 

  22. Rillig, M. C. et al. Plant species-specific changes in root inhabiting fungi in a California annual grassland: responses to elevated CO2 and nutrients. Oecologia 113, 252–259 (1997).

    Article  ADS  Google Scholar 

  23. Ball, A. S. Microbial decomposition at elevated CO2 levels: effect of litter quality. Glob. Change Biol. 3, 379– 386 (1997).

    Article  ADS  Google Scholar 

  24. Klironomos, J. N., Rillig, M. C. & Allen, M. F. Below-ground microbial and microfaunal responses to Artemisia tridentata grown under elevated atmospheric CO2. Funct. Ecol. 10, 527–534 (1996).

    Article  Google Scholar 

  25. Rillig, M. C., Field, C. B. & Allen, M. F. Soil biota responses to long-term atmospheric CO 2 enrichment in two California annual grasslands. Oecologia 119, 572–577 ( 1999).

    Article  ADS  Google Scholar 

  26. Rillig, M. C., Wright, S. F., Allen, M. F. & Field, C. B. Rise in carbon dioxide changes soil structure. Nature 400, 628 (1999).

    Article  ADS  CAS  Google Scholar 

  27. Tisdall, J. M. Possible role of soil microorganisms in aggregation in soils. Plant Soil 159, 115–121 (1994).

    Article  Google Scholar 

  28. Berntson, G. M. & Bazzaz, F. A. Belowground positive and negative feedbacks on CO2 growth enhancement. Plant Soil 187, 119–131 (1996).

    Article  CAS  Google Scholar 

  29. Vance, E. D., Brookes, P. C. & Jenkinson, D. S. An extraction method for measuring soil microbial biomass C. Soil Biol. Biochem. 19, 703– 707 (1987).

    Article  CAS  Google Scholar 

  30. Stark, J. M. & Hart, S. C. Diffusion technique for preparing salt solutions, Kjeldahl digests, and persulfate digests for nitrogen-15 analysis. Soil Sci. Soc. Am. J. 60, 1846– 1855 (1996).

    Article  ADS  CAS  Google Scholar 

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We thank H. A. Mooney, C. Lund and B. A. Hungate for contributing to the design and execution of the field experiment, H. L. Zhong for 15N measurements, and P. Brooks for assistance with 13C measurements. The Jasper Ridge CO2 experiment was supported by grants from the National Science Foundation to the Carnegie Institution of Washington, the University of California, Berkeley, and Stanford University. S.H. was supported by the US NSF under a fellowship awarded in 1996.

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Hu, S., Chapin, F., Firestone, M. et al. Nitrogen limitation of microbial decomposition in a grassland under elevated CO2. Nature 409, 188–191 (2001).

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