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| Titel |
The fate of buried organic carbon in colluvial soils: a long-term perspective |
| VerfasserIn |
Z. Wang, K. Van Oost, A. Lang, T. Quine, W. Clymans, R. Merckx, B. Notebaert, G. Govers |
| 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. 3 ; Nr. 11, no. 3 (2014-02-13), S.873-883 |
| Datensatznummer |
250117202
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| Publikation (Nr.) |
 copernicus.org/bg-11-873-2014.pdf |
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| Zusammenfassung |
| Colluvial soils are enriched in soil organic carbon (SOC) in comparison to
the soils of upslope areas due to the deposition and progressive burial of
SOC. This burial of SOC has important implications for the global carbon
cycle, but the long-term dynamics of buried SOC remain poorly constrained.
We addressed this issue by determining the SOC burial efficiency (i.e. the
fraction of originally deposited SOC that is preserved in colluvial
deposits) of buried SOC as well as the SOC stability in colluvial soils. We
quantified the turnover rate of deposited SOC by establishing sediment and
SOC burial chronologies. The SOC stability was derived from soil incubation
experiments and the δ13C values of SOC. The C burial efficiency
was found to decrease with time, reaching a constant ratio of approximately
17% by about 1000–1500 yr post-burial. This decrease is attributed
to the increasing recalcitrance of the remaining buried SOC with time and a
less favourable environment for SOC decomposition with increasing depth.
Buried SOC in colluvial profiles was found to be more stable and degraded in
comparison to SOC sampled at the same depth at a stable reference location.
This is due to the preferential mineralisation of the labile fraction of the
deposited SOC. Our study shows that SOC responds to burial over a centennial
timescale; however, more insight into the factors controlling this response
is required to fully understand how this timescale may vary, depending on
specific conditions such as climate and depositional environment. |
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