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| Titel |
Carbon balance assessment of a natural steppe of southern Siberia by multiple constraint approach |
| VerfasserIn |
L. Belelli Marchesini, D. Papale, M. Reichstein, N. Vuichard, N. Tchebakova, R. Valentini |
| 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 ; 4, no. 4 ; Nr. 4, no. 4 (2007-08-02), S.581-595 |
| Datensatznummer |
250001855
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| Publikation (Nr.) |
 copernicus.org/bg-4-581-2007.pdf |
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| Zusammenfassung |
Steppe ecosystems represent an interesting case in which the assessment of
carbon balance may be performed through a cross validation of the eddy
covariance measurements against ecological inventory estimates of carbon
exchanges (Ehman et al., 2002; Curtis et al., 2002).
Indeed, the widespread presence of ideal conditions for the applicability of
the eddy covariance technique, as vast and homogeneous grass vegetation
cover over flat terrains (Baldocchi, 2003), make steppes a suitable ground
to ensure a constrain to flux estimates with independent methodological
approaches.
We report about the analysis of the carbon cycle of a true steppe ecosystem
in southern Siberia during the growing season of 2004 in the framework of
the TCOS-Siberia project activities performed by continuous monitoring of
CO2 fluxes at ecosystem scale by the eddy covariance method,
fortnightly samplings of phytomass, and ingrowth cores extractions for NPP
assessment, and weekly measurements of heterotrophic component of soil
CO2 effluxes obtained by an experiment of root exclusion.
The carbon balance of the monitored natural steppe was, according to
micrometeorological measurements, a sink of carbon of 151.7±36.9 g C
m−2, cumulated during the growing season from May to September. This
result was in agreement with the independent estimate through ecological
inventory which yielded a sink of 150.1 g C m−2 although this method was
characterized by a large uncertainty (±130%) considering the 95%
confidence interval of the estimate. Uncertainties in belowground process
estimates account for a large part of the error. Thus, in particular efforts
to better quantify the dynamics of root biomass (growth and turnover) have
to be undertaken in order to reduce the uncertainties in the assessment of
NPP. This assessment should be preferably based on the application of
multiple methods, each one characterized by its own merits and flaws. |
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