title: Substrate and environmental controls on microbial assimilation of soil organic carbon: a framework for Earth system models.
abstract: A mechanistic understanding of microbial assimilation of soil organic carbon is important to improve Earth system models' ability to simulate carbon-climate feedbacks. A simple modelling framework was developed to investigate how substrate quality and environmental controls over microbial activity regulate microbial assimilation of soil organic carbon and on the size of the microbial biomass. Substrate quality has a positive effect on microbial assimilation of soil organic carbon: higher substrate quality leads to higher ratio of microbial carbon to soil organic carbon. Microbial biomass carbon peaks and then declines as cumulative activity increases. The simulated ratios of soil microbial biomass to soil organic carbon are reasonably consistent with a recently compiled global data set at the biome level. The modelling framework developed in this study offers a simple approach to incorporate microbial contributions to the carbon cycling into Earth system models to simulate carbon-climate feedbacks and explain global patterns of microbial biomass.
authors: Climate Change Science Institute and Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
authors: Xiaofeng
authors: X
authors: Xu
authors: Joshua P
authors: JP
authors: Schimel
authors: Peter E
authors: PE
authors: Thornton
authors: Xia
authors: X
authors: Song
authors: Fengming
authors: F
authors: Yuan
authors: Santonu
authors: S
authors: Goswami
mesh_terms: D002244:Carbon / Q000378:metabolism*; D004777:Environment; D064307:Microbiota / Q000502:physiology*; D008954:Models, Biological; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology
chemical_list: D012987:Soil; D002244:Carbon
keywords: Cumulative microbial activity index; microbial annual active period; microbial assimilation; substrate quality