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| Titel |
Diel variations in the carbon isotope composition of respired CO2 and associated carbon sources: a review of dynamics and mechanisms |
| VerfasserIn |
C. Werner, A. Gessler |
| 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 ; 8, no. 9 ; Nr. 8, no. 9 (2011-09-06), S.2437-2459 |
| Datensatznummer |
250006112
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| Publikation (Nr.) |
 copernicus.org/bg-8-2437-2011.pdf |
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| Zusammenfassung |
| Recent advances have improved our methodological approaches and theoretical
understanding of post-photosynthetic carbon isotope fractionation processes.
Nevertheless we still lack a clear picture of the origin of short-term
variability in δ13C of respired CO2 (δ13Cres)
and organic carbon fractions on a diel basis. Closing
this knowledge gap is essential for the application of stable isotope
approaches for partitioning ecosystem respiration, tracing carbon flow
through plants and ecosystems and disentangling key physiological processes
in carbon metabolism of plants. In this review we examine the short-term
dynamics in δ13Cres and putative substrate pools at the
plant, soil and ecosystem scales and discuss mechanisms, which might drive
diel δ13Cres dynamics at each scale. Maximum reported
variation in diel δ13Cres is 4.0, 5.4 and 14.8 ‰ in trunks,
roots and leaves of different species and 12.5 and 8.1 ‰ at the soil and
ecosystem scale in different biomes. Temporal variation in
post-photosynthetic isotope fractionation related to changes in carbon
allocation to different metabolic pathways is the most plausible mechanistic
explanation for observed diel dynamics in δ13Cres. In
addition, mixing of component fluxes with different temporal dynamics and
isotopic compositions add to the δ13Cres variation on the
soil and ecosystem level. Understanding short-term variations in δ13Cres
is particularly important for ecosystem studies, since
δ13Cres contains information on the fate of respiratory
substrates, and may, therefore, provide a non-intrusive way to identify
changes in carbon allocation patterns. |
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