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| Titel |
Colimitation of decomposition by substrate and decomposers – a comparison of model formulations |
| VerfasserIn |
T. Wutzler, M. Reichstein |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 5, no. 3 ; Nr. 5, no. 3 (2008-05-13), S.749-759 |
| Datensatznummer |
250002520
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| Publikation (Nr.) |
 copernicus.org/bg-5-749-2008.pdf |
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| Zusammenfassung |
| Decomposition of soil organic matter (SOM) is limited by both the available
substrate and the active decomposer community. The understanding of this
colimitation strongly affects the understanding of feedbacks of soil carbon to
global warming and its consequences. This study compares different formulations
of soil organic matter (SOM) decomposition. We compiled formulations from
literature into groups according to the representation of decomposer biomass on
the SOM decomposition rate a) non-explicit (substrate only), b) linear, and c)
non-linear. By varying the SOM decomposition equation in a basic simplified
decomposition model, we analyzed the following questions. Is the priming effect
represented? Under which conditions is SOM accumulation limited? And, how does
steady state SOM stocks scale with amount of fresh organic matter (FOM) litter
inputs? While formulations (a) did not represent the priming effect, with
formulations (b) steady state SOM stocks were independent of amount of litter
input. Further, with several formulations (c) there was an offset of SOM that
was not decomposed when no fresh OM was supplied. The finding that a part of
the SOM is not decomposed on exhaust of FOM supply supports the hypothesis of
carbon stabilization in deep soil by the absence of energy-rich fresh organic
matter. Different representations of colimitation of decomposition by substrate
and decomposers in SOM decomposition models resulted in qualitatively different
long-term behaviour. A collaborative effort by modellers and experimentalists
is required to identify formulations that are more or less suitable to
represent the most important drivers of long term carbon storage. |
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