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| Titel |
CO2 fluxes and ecosystem dynamics at five European treeless peatlands – merging data and process oriented modeling |
| VerfasserIn |
C. Metzger, P.-E. Jansson, A. Lohila, M. Aurela, T. Eickenscheidt, L. Belelli-Marchesini, K. J. Dinsmore, J. Drewer, J. van Huissteden, M. Drösler |
| 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 ; 12, no. 1 ; Nr. 12, no. 1 (2015-01-09), S.125-146 |
| Datensatznummer |
250117762
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| Publikation (Nr.) |
 copernicus.org/bg-12-125-2015.pdf |
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| Zusammenfassung |
The carbon dioxide (CO2) exchange of five different peatland systems
across Europe with a wide gradient in land use intensity, water table depth,
soil fertility and climate was simulated with the process oriented
CoupModel. The aim of the study was to find out whether CO2 fluxes,
measured at different sites, can be explained by common processes and
parameters or to what extend a site specific configuration is needed. The
model was calibrated to fit measured CO2 fluxes, soil temperature, snow
depth and leaf area index (LAI) and resulting differences in model
parameters were analyzed. Finding site independent model parameters would
mean that differences in the measured fluxes could be explained solely by
model input data: water table, meteorological data, management and soil
inventory data.
Seasonal variability in the major fluxes was well captured, when a site
independent configuration was utilized for most of the parameters.
Parameters that differed between sites included the rate of soil organic
decomposition, photosynthetic efficiency, and regulation of the mobile
carbon (C) pool from senescence to shooting in the next year.
The largest difference between sites was the rate coefficient for
heterotrophic respiration. Setting it to a common value would lead to
underestimation of mean total respiration by a factor of 2.8 up to an
overestimation by a factor of 4. Despite testing a wide range of different
responses to soil water and temperature, rate coefficients for heterotrophic
respiration were consistently the lowest on formerly drained sites and the highest
on the managed sites. Substrate decomposability, pH and vegetation
characteristics are possible explanations for the differences in
decomposition rates.
Specific parameter values for the timing of plant shooting and senescence,
the photosynthesis response to temperature, litter fall and plant
respiration rates, leaf morphology and allocation fractions of new
assimilates, were not needed, even though the gradient in site latitude
ranged from 48° N (southern Germany) to 68° N (northern
Finland) differed largely in their vegetation. This was also true for common
parameters defining the moisture and temperature response for decomposition,
leading to the conclusion that a site specific interpretation of these
processes is not necessary. In contrast, the rate of soil organic
decomposition, photosynthetic efficiency, and the regulation of the mobile
carbon pool need to be estimated from available information on specific
soil conditions, vegetation and management of the ecosystems, to be able to
describe CO2 fluxes under different conditions. |
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