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| Titel |
Spatio-temporal variability of soil respiration in a spruce-dominated headwater catchment in western Germany |
| VerfasserIn |
A. Y. Bossa, B. Diekkrüger |
| 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 ; 11, no. 15 ; Nr. 11, no. 15 (2014-08-12), S.4235-4249 |
| Datensatznummer |
250117545
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| Publikation (Nr.) |
 copernicus.org/bg-11-4235-2014.pdf |
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| Zusammenfassung |
CO2 production and transport from forest floors is an important
component of the carbon cycle and is closely related to the global atmosphere
CO2 concentration. If we are to understand the feedback between soil
processes and atmospheric CO2, we need to know more about the
spatio-temporal variability of this soil respiration under different
environmental conditions. In this study, long-term measurements were
conducted in a spruce-dominated forest ecosystem in western Germany.
Multivariate analysis-based similarities between different measurement sites
led to the detection of site clusters along two CO2 emission axes:
(1) mainly controlled by soil temperature and moisture condition, and
(2) mainly controlled by root biomass and the forest floor litter. The
combined effects of soil temperature and soil moisture were used as a
time-dependent rating factor affecting the optimal CO2 production and
transport at cluster level. High/moderate/weak time-dependent rating factors
were associated with the different clusters. The process-based, most distant
clusters were identified using specified pattern characteristics: the
reaction rates in the soil layers, the activation energy for bio-chemical
reactions, the soil moisture dependency parameter, the root biomass factor,
the litter layer factor and the organic matter factor. A HYDRUS-1D model
system was inversely used to compute soil hydraulic parameters from soil
moisture measurements. Heat transport parameters were calibrated based on
observed soil temperatures. The results were used to adjust CO2
productions by soil microorganisms and plant roots under optimal conditions
for each cluster. Although the uncertainty associated with the HYDRUS-1D
simulations is higher, the results were consistent with both the multivariate
clustering and the time-dependent rating of site production.
Finally, four clusters with significantly different environmental conditions
(i.e. permanent high soil moisture condition, accumulated litter amount,
high variability in soil moisture content, and dominant temperature dependence)
were found to be relevant in explaining the spatio-temporal variability of CO2
efflux and providing reference-specific characteristic values for the
investigated area. |
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