Stoichiometrically coupled carbon and nitrogen cycling in the MIcrobial-MIneral Carbon Stabilization model version 1.0 (MIMICS-CN v1.0)
<p>Explicit consideration of microbial physiology in soil biogeochemical models that represent coupled carbon–nitrogen dynamics presents opportunities to deepen understanding of ecosystem responses to environmental change. The MIcrobial-MIneral Carbon Stabilization (MIMICS) model explicitly re...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2020-09-01
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| Series: | Geoscientific Model Development |
| Online Access: | https://gmd.copernicus.org/articles/13/4413/2020/gmd-13-4413-2020.pdf |
| Summary: | <p>Explicit consideration of microbial physiology in soil
biogeochemical models that represent coupled carbon–nitrogen dynamics
presents opportunities to deepen understanding of ecosystem responses to
environmental change. The MIcrobial-MIneral Carbon Stabilization (MIMICS)
model explicitly represents microbial physiology and physicochemical
stabilization of soil carbon (C) on regional and global scales. Here we
present a new version of MIMICS with coupled C and nitrogen (N) cycling
through litter, microbial, and soil organic matter (SOM) pools. The model
was parameterized and validated against C and N data from the Long-Term
Inter-site Decomposition Experiment Team (LIDET; six litter types, 10 years of
observations, and 13 sites across North America). The model simulates C and N
losses from litterbags in the LIDET study with reasonable accuracy (C:
<span class="inline-formula"><i>R</i><sup>2</sup>=0.63</span>; N: <span class="inline-formula"><i>R</i><sup>2</sup>=0.29</span>), which is comparable with simulations
from the DAYCENT model that implicitly represents microbial activity (C:
<span class="inline-formula"><i>R</i><sup>2</sup>=0.67</span>; N: <span class="inline-formula"><i>R</i><sup>2</sup>=0.30</span>). Subsequently, we evaluated equilibrium
values of stocks (total soil C and N, microbial biomass C and N, inorganic
N) and microbial process rates (soil heterotrophic respiration, N
mineralization) simulated by MIMICS-CN across the 13 simulated LIDET sites
against published observations from other continent-wide datasets. We found
that MIMICS-CN produces equilibrium values in line with measured values,
showing that the model generates plausible estimates of ecosystem soil
biogeochemical dynamics across continental-scale gradients. MIMICS-CN
provides a platform for coupling C and N projections in a microbially explicit
model, but experiments still need to identify the physiological and
stoichiometric characteristics of soil microbes, especially under
environmental change scenarios.</p> |
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| ISSN: | 1991-959X 1991-9603 |