Ecosystems

, Volume 5, Issue 7, pp 0680–0691

Phosphorus Limitation of Microbial Processes in Moist Tropical Forests: Evidence from Short-term Laboratory Incubations and Field Studies

  • Cory C. Cleveland
  • Alan R. Townsend
  • Steven K. Schmidt

DOI: 10.1007/s10021-002-0202-9

Cite this article as:
Cleveland, C., Townsend, A. & Schmidt, S. Ecosystems (2002) 5: 0680. doi:10.1007/s10021-002-0202-9
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Abstract

Although there is a widespread belief that phosphorus (P) limits basic ecosystem processes in moist tropical forests, direct tests of this supposition are rare. At the same time, it is generally believed that P does not limit soil microorganism respiration or growth in terrestrial ecosystems. We used natural gradients in P fertility created by soils of varying age underlying tropical rain forests in southwestern Costa Rica, combined with direct manipulations of carbon (C) and P supply, to test the effects of P availability on the decomposition of multiple forms of C, including dissolved organic carbon (DOC) and soil organic carbon (SOC). Results from a combination of laboratory and field experiments suggest that C decomposition in old, highly weathered oxisol soils is strongly constrained by P availability. In addition, P additions to these soils (no C added) also revealed that microbial utilization of at least labile fractions of SOC was also P limited. To our knowledge, this is the first direct evidence of P limitation of microbial processes in tropical rain forest soil. We suggest that P limitation of microbial decomposition may have profound implications for C cycling in moist tropical forests, including their potential response to increasing atmospheric carbon dioxide. Furthermore, this site is still relatively rich in P when compared to many other tropical forests on old soils; thus, we believe that P limitation of soil microorganisms throughout the humid tropics is a possibility.

Key words: decomposition; soil microorganisms; nutrient limitation; fertilization; tropical rain forest; phosphorus; carbon. 

Copyright information

© Springer-Verlag New York Inc. 2002

Authors and Affiliations

  • Cory C. Cleveland
    • 1
  • Alan R. Townsend
    • 1
  • Steven K. Schmidt
    • 2
  1. 1.Institute of Arctic and Alpine Research (INSTAAR), University of Colorado, Campus Box 450, Boulder, Colorado 80309, USA; andUS
  2. 2.Department of Environmental, Population, and Organismic Biology, Campus Box 334, University of Colorado, Boulder, Colorado 80309, USAUS

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