, Volume 117, Issue 1, pp 205–227 | Cite as

Enzymatic and detrital influences on the structure, function, and dynamics of spatially-explicit model ecosystems

  • John C. Moore
  • Randall B. Boone
  • Akihiro Koyama
  • Kirstin Holfelder


We developed agent-based models patterned after the equation-based models developed by Schimel and Weintraub (Soil Biol Biochem 35:549–563, 2003) to explore the influence of microbial-derived extracellular enzymes on carbon (C) dynamics. The models featured spatial arrangements of detritus as either randomly-spaced particles (rain) or as root-like structures (root), detritus input intervals (continuous vs. pulsed) and rates (0–5,000 units in 500 unit intervals), trophic structures (presence or absence of predators preying on microbes), and extracellular enzymes with different half-lives (1, 10, 100, and 1,000 time steps). We studied how these features affected C dynamics and model persistence (no extinctions). Models without predators were more likely to persist than those with predators, and their C dynamics could be explained with energetics-based arguments. When predators were present, two of the four model configurations—root-continuous and rain-pulsed—were more likely to persist. The root-continuous models were more likely to persist at lower detritus input rates (500–3,500 units), while the rain-pulsed models were more likely to persist at intermediate detritus input rates (2,000–3,500 units). For both these model configurations, shorter extracellular enzyme half-lives increased the likelihood of persistence. Consistent with the results of Schimel and Weintraub (Soil Biol Biochem 35:549–563, 2003), C dynamics was governed by extracellular enzyme production activity and loss. Our results demonstrated that extracellular enzyme control of C dynamics depends on the spatial arrangement of resources, the input rate and input intervals of detritus and trophic structure.


Agent-based model Enzymes Soil food web Spatial distribution Trophic structure 



We thank Matthew Wallenstein, Mary Stromberger, Richard Dick, and Colin Bell for organizing the workshop, presenters and participants at the workshop for their insights, guidance and discussion, and the anonymous reviewers for their comments. Funding for this research was provided by grants from the US National Science Foundation (OPP-0425606, DEB-0423385, DEB-0840869, ARC-0909441, DEB-0919383).

Supplementary material

10533_2013_9932_MOESM1_ESM.doc (116 kb)
Supplementary material 1 (DOC 115 kb)


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Copyright information

© Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  • John C. Moore
    • 1
    • 2
  • Randall B. Boone
    • 1
    • 2
  • Akihiro Koyama
    • 2
    • 3
  • Kirstin Holfelder
    • 4
  1. 1.Department of Ecosystem Sciences and SustainabilityColorado State UniversityFort CollinsUSA
  2. 2.Natural Resource Ecology LaboratoryColorado State UniversityFort CollinsUSA
  3. 3.Department of BiologyColorado State UniversityFort CollinsUSA
  4. 4.Colorado Natural Heritage ProgramColorado State UniversityFort CollinsUSA

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