Biogeochemistry

, Volume 95, Issue 1, pp 23–35

The trade-off between growth rate and yield in microbial communities and the consequences for under-snow soil respiration in a high elevation coniferous forest

Authors

    • Department of BiologySan Diego State University
  • Russell K. Monson
    • University of Colorado
  • Steven K. Schmidt
    • University of Colorado
  • Michael N. Weintraub
    • University of Toledo
Article

DOI: 10.1007/s10533-008-9252-1

Cite this article as:
Lipson, D.A., Monson, R.K., Schmidt, S.K. et al. Biogeochemistry (2009) 95: 23. doi:10.1007/s10533-008-9252-1

Abstract

Soil microbial respiration is a critical component of the global carbon cycle, but it is uncertain how properties of microbes affect this process. Previous studies have noted a thermodynamic trade-off between the rate and efficiency of growth in heterotrophic organisms. Growth rate and yield determine the biomass-specific respiration rate of growing microbial populations, but these traits have not previously been used to scale from microbial communities to ecosystems. Here we report seasonal variation in microbial growth kinetics and temperature responses (Q10) in a coniferous forest soil, relate these properties to cultured and uncultured soil microbes, and model the effects of shifting growth kinetics on soil heterotrophic respiration (Rh). Soil microbial communities from under-snow had higher growth rates and lower growth yields than the summer and fall communities from exposed soils, causing higher biomass-specific respiration rates. Growth rate and yield were strongly negatively correlated. Based on experiments using specific growth inhibitors, bacteria had higher growth rates and lower yields than fungi, overall, suggesting a more important role for bacteria in determining Rh. The dominant bacteria from laboratory-incubated soil differed seasonally: faster-growing, cold-adapted Janthinobacterium species dominated in winter and slower-growing, mesophilic Burkholderia and Variovorax species dominated in summer. Modeled Rh was sensitive to microbial kinetics and Q10: a sixfold lower annual Rh resulted from using kinetic parameters from summer versus winter communities. Under the most realistic scenario using seasonally changing communities, the model estimated Rh at 22.67 mol m−2 year−1, or 47.0% of annual total ecosystem respiration (Re) for this forest.

Keywords

Abies lasiocarpa Burkholderia Janthinobacterium Pinus contorta Picea engelmanii Variovorax

Abbreviations

SIGR

Substrate induced growth response

SIR

Substrate induced respiration

Rh

Heterotrophic respiration

Rs

Soil respiration

Re

Ecosystem respiration

Copyright information

© Springer Science+Business Media B.V. 2008