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| Titel |
Organic carbon mobilization in the slope-bed connection through different erosion processes |
| VerfasserIn |
Elisabet Nadeu, Carolina Boix-Fayos, Joris de Vente, Jorge López, Maria Martínez-Mena |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250033821
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| Zusammenfassung |
| Soil organic carbon (OC) mobilization due to erosional processes can have consequences
regarding CO2 emission or sequestration. OC can be mineralized (emitted as CO2 to the
atmosphere) during detachment, transport and deposition of soil particles, or buried in
depositional settings, where it can also be stabilized. The contradicting results in the
published literature in the last decade point towards a lack of information concerning OC
dynamics in relation to different erosion processes at different spatial scales. The objective of
this work was to characterize the quantity and type of erosion OC mobilized by the different
erosion processes identified at a catchment scale with respect to the original soils where they
came from.
With the purpose of analysing the type (labile or stable) and quantity of organic carbon
(OC) mobilized by different erosive processes identified at the slope-bed connection, the
erosion deposits of gullies, sheet erosion, bank erosion and tillage erosion were studied in
a small catchment (10 ha) and compared to the characteristics of the catchment
soils. Selectivity of particles upon soil detachment and transport in the different
processes was associated to different OC content in the deposits (from more to less
OC concentration: tillage>gully>interrill>gravitational-bank erosion). OC was
predominantly found in a stable form (mineral associated organic carbon) and accounted for
77% (± 15) of total organic carbon in sediments. Further, sediment OC enrichment
ratio was in all cases below unity (~0,40 ±0,26) in spite of a slight increase in the
finer soil texture fractions (those associated with OC) in the deposits. These results
were attributed to sediment transport, not only suspended, but also due to other
transport processes important at catchment scales, with coarser and less OC enriched
particles; as well as to the exposition of sediments in the sampled deposits that
favoured mineralization. The geomorphological analysis revealed active fluvial
dynamics where detachment and transport processes were predominant and where
natural sinks (alluvial bars, depositional basins, wetlands) or even artificial ones
(hydraulic works), that would favour deposition and sediment burial, were missing. |
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