Biogeochemistry

, Volume 119, Issue 1, pp 67–84

Soil carbon sensitivity to temperature and carbon use efficiency compared across microbial-ecosystem models of varying complexity

  • Jianwei Li
  • Gangsheng Wang
  • Steven D. Allison
  • Melanie A. Mayes
  • Yiqi Luo
Article

DOI: 10.1007/s10533-013-9948-8

Cite this article as:
Li, J., Wang, G., Allison, S.D. et al. Biogeochemistry (2014) 119: 67. doi:10.1007/s10533-013-9948-8

Abstract

Global ecosystem models may require microbial components to accurately predict feedbacks between climate warming and soil decomposition, but it is unclear what parameters and levels of complexity are ideal for scaling up to the globe. Here we conducted a model comparison using a conventional model with first-order decay and three microbial models of increasing complexity that simulate short- to long-term soil carbon dynamics. We focused on soil carbon responses to microbial carbon use efficiency (CUE) and temperature. Three scenarios were implemented in all models: constant CUE (held at 0.31), varied CUE (−0.016 °C−1), and 50 % acclimated CUE (−0.008 °C−1). Whereas the conventional model always showed soil carbon losses with increasing temperature, the microbial models each predicted a temperature threshold above which warming led to soil carbon gain. The location of this threshold depended on CUE scenario, with higher temperature thresholds under the acclimated and constant scenarios. This result suggests that the temperature sensitivity of CUE and the structure of the soil carbon model together regulate the long-term soil carbon response to warming. Equilibrium soil carbon stocks predicted by the microbial models were much less sensitive to changing inputs compared to the conventional model. Although many soil carbon dynamics were similar across microbial models, the most complex model showed less pronounced oscillations. Thus, adding model complexity (i.e. including enzyme pools) could improve the mechanistic representation of soil carbon dynamics during the transient phase in certain ecosystems. This study suggests that model structure and CUE parameterization should be carefully evaluated when scaling up microbial models to ecosystems and the globe.

Keywords

WarmingSoil organic matter decompositionFirst-order decay modelMicrobial-enzyme modelCarbon use efficiencyTemperature threshold

Supplementary material

10533_2013_9948_MOESM1_ESM.doc (347 kb)
Supplementary material 1 (DOC 347 kb)

Copyright information

© Springer Science+Business Media Dordrecht 2014

Authors and Affiliations

  • Jianwei Li
    • 1
  • Gangsheng Wang
    • 2
  • Steven D. Allison
    • 3
    • 4
  • Melanie A. Mayes
    • 2
  • Yiqi Luo
    • 1
  1. 1.Department of Botany and MicrobiologyUniversity of OklahomaNormanUSA
  2. 2.Environmental Sciences Division and Climate Change Science InstituteOak Ridge National LaboratoryOak RidgeUSA
  3. 3.Department of Ecology and Evolutionary BiologyUniversity of CaliforniaIrvineUSA
  4. 4.Department of Earth System ScienceUniversity of CaliforniaIrvineUSA