Representing life in the Earth system with soil microbial functional traits in the MIMICS model

Projecting biogeochemical responses to global environmental change requires multi-scaled perspectives that consider organismal diversity, ecosystem processes, and global fluxes. However, microbes, the drivers of soil organic matter decomposition and stabilization, remain notably absent from models u...

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Main Authors: W. R. Wieder, A. S. Grandy, C. M. Kallenbach, P. G. Taylor, G. B. Bonan
Format: Article
Language:English
Published: Copernicus Publications 2015-06-01
Series:Geoscientific Model Development
Online Access:http://www.geosci-model-dev.net/8/1789/2015/gmd-8-1789-2015.pdf
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author W. R. Wieder
A. S. Grandy
C. M. Kallenbach
P. G. Taylor
G. B. Bonan
author_facet W. R. Wieder
A. S. Grandy
C. M. Kallenbach
P. G. Taylor
G. B. Bonan
author_sort W. R. Wieder
collection DOAJ
description Projecting biogeochemical responses to global environmental change requires multi-scaled perspectives that consider organismal diversity, ecosystem processes, and global fluxes. However, microbes, the drivers of soil organic matter decomposition and stabilization, remain notably absent from models used to project carbon (C) cycle–climate feedbacks. We used a microbial trait-based soil C model with two physiologically distinct microbial communities, and evaluate how this model represents soil C storage and response to perturbations. Drawing from the application of functional traits used to model other ecosystems, we incorporate copiotrophic and oligotrophic microbial functional groups in the MIcrobial-MIneral Carbon Stabilization (MIMICS) model; these functional groups are akin to "gleaner" vs. "opportunist" plankton in the ocean, or <I>r</I>- vs. <I>K</I>-strategists in plant and animal communities. Here we compare MIMICS to a conventional soil C model, DAYCENT (the daily time-step version of the CENTURY model), in cross-site comparisons of nitrogen (N) enrichment effects on soil C dynamics. MIMICS more accurately simulates C responses to N enrichment; moreover, it raises important hypotheses involving the roles of substrate availability, community-level enzyme induction, and microbial physiological responses in explaining various soil biogeochemical responses to N enrichment. In global-scale analyses, we show that MIMICS projects much slower rates of soil C accumulation than a conventional soil biogeochemistry in response to increasing C inputs with elevated carbon dioxide (CO<sub>2</sub>) – a finding that would reduce the size of the land C sink estimated by the Earth system. Our findings illustrate that tradeoffs between theory and utility can be overcome to develop soil biogeochemistry models that evaluate and advance our theoretical understanding of microbial dynamics and soil biogeochemical responses to environmental change.
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spelling doaj.art-834b328d207e41ac8bb79f059f04cd312022-12-22T00:48:16ZengCopernicus PublicationsGeoscientific Model Development1991-959X1991-96032015-06-01861789180810.5194/gmd-8-1789-2015Representing life in the Earth system with soil microbial functional traits in the MIMICS modelW. R. Wieder0A. S. Grandy1C. M. Kallenbach2P. G. Taylor3G. B. Bonan4Climate and Global Dynamics Division, National Center for Atmospheric Research, Boulder, CO, USADepartment of Natural Resources and the Environment, University of New Hampshire, Durham, NH, USADepartment of Natural Resources and the Environment, University of New Hampshire, Durham, NH, USAInstitute for Arctic and Alpine Research, University of Colorado, Boulder, CO, USAClimate and Global Dynamics Division, National Center for Atmospheric Research, Boulder, CO, USAProjecting biogeochemical responses to global environmental change requires multi-scaled perspectives that consider organismal diversity, ecosystem processes, and global fluxes. However, microbes, the drivers of soil organic matter decomposition and stabilization, remain notably absent from models used to project carbon (C) cycle–climate feedbacks. We used a microbial trait-based soil C model with two physiologically distinct microbial communities, and evaluate how this model represents soil C storage and response to perturbations. Drawing from the application of functional traits used to model other ecosystems, we incorporate copiotrophic and oligotrophic microbial functional groups in the MIcrobial-MIneral Carbon Stabilization (MIMICS) model; these functional groups are akin to "gleaner" vs. "opportunist" plankton in the ocean, or <I>r</I>- vs. <I>K</I>-strategists in plant and animal communities. Here we compare MIMICS to a conventional soil C model, DAYCENT (the daily time-step version of the CENTURY model), in cross-site comparisons of nitrogen (N) enrichment effects on soil C dynamics. MIMICS more accurately simulates C responses to N enrichment; moreover, it raises important hypotheses involving the roles of substrate availability, community-level enzyme induction, and microbial physiological responses in explaining various soil biogeochemical responses to N enrichment. In global-scale analyses, we show that MIMICS projects much slower rates of soil C accumulation than a conventional soil biogeochemistry in response to increasing C inputs with elevated carbon dioxide (CO<sub>2</sub>) – a finding that would reduce the size of the land C sink estimated by the Earth system. Our findings illustrate that tradeoffs between theory and utility can be overcome to develop soil biogeochemistry models that evaluate and advance our theoretical understanding of microbial dynamics and soil biogeochemical responses to environmental change.http://www.geosci-model-dev.net/8/1789/2015/gmd-8-1789-2015.pdf
spellingShingle W. R. Wieder
A. S. Grandy
C. M. Kallenbach
P. G. Taylor
G. B. Bonan
Representing life in the Earth system with soil microbial functional traits in the MIMICS model
Geoscientific Model Development
title Representing life in the Earth system with soil microbial functional traits in the MIMICS model
title_full Representing life in the Earth system with soil microbial functional traits in the MIMICS model
title_fullStr Representing life in the Earth system with soil microbial functional traits in the MIMICS model
title_full_unstemmed Representing life in the Earth system with soil microbial functional traits in the MIMICS model
title_short Representing life in the Earth system with soil microbial functional traits in the MIMICS model
title_sort representing life in the earth system with soil microbial functional traits in the mimics model
url http://www.geosci-model-dev.net/8/1789/2015/gmd-8-1789-2015.pdf
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