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| Titel |
A method to detect soil carbon degradation during soil erosion |
| VerfasserIn |
C. Alewell, M. Schaub, F. Conen |
| 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 ; 6, no. 11 ; Nr. 6, no. 11 (2009-11-10), S.2541-2547 |
| Datensatznummer |
250004090
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| Publikation (Nr.) |
 copernicus.org/bg-6-2541-2009.pdf |
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| Zusammenfassung |
| Soil erosion has been discussed intensively but controversial both as a
significant source or a significant sink of atmospheric carbon possibly
explaining the gap in the global carbon budget. One of the major points of
discussion has been whether or not carbon is degraded and mineralized to
CO2 during detachment, transport and deposition of soil material. By
combining the caesium-137 (137Cs) approach (quantification of erosion
rates) with stable carbon isotope signatures (process indicator of mixing
versus degradation of carbon pools) we were able to show that degradation of
carbon occurs during soil erosion processes at the investigated mountain
grasslands in the central Swiss Alps (Urseren Valley, Canton Uri). Transects
from upland (erosion source) to wetland soils (erosion sinks) of sites
affected by sheet and land slide erosion were sampled. Analysis of
137Cs yielded an input of 2 and 4.6 tha−1 yr−1 of soil
material into the wetlands sites. Assuming no degradation of soil organic
carbon during detachment and transport, carbon isotope signature of soil
organic carbon in the wetlands could only be explained with an assumed
500–600 and 350–400 years of erosion input into the wetlands Laui and Spissen,
respectively. The latter is highly unlikely with alpine peat growth rates
indicating that the upper horizons might have an age between 7 and 200
years. While we do not conclude from our data that eroded soil organic
carbon is generally degraded during detachment and transport, we propose
this method to gain more information on process dynamics during soil erosion
from oxic upland to anoxic wetland soils, sediments or water bodies. |
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