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| Titel |
Turnover of eroded soil organic carbon after deposition in terrestrial and aquatic environments |
| VerfasserIn |
Frédérique Kirkels, Erik Cammeraat, Karsten Kalbitz, Kristof Van Oost, Ruth Ellerbrock, Stéphane Follain, Lucia Fuchslueger, Horst Gerke, Goswin Heckrath, Ingrid Kögel-Knabner, Nikolaus Kuhn, Emiel Van Loon, John Quinton, Andreas Richter, Sébastien Salvador-Blanes, Michael Sommer, Markus Steffens |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250101252
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| Publikation (Nr.) |
 EGU/EGU2015-362.pdf |
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| Zusammenfassung |
| The fate of eroded soil organic carbon (SOC) after deposition is a large uncertainty in assessing the impact of soil erosion on C budgets. Globally, large amounts of SOC are transported by erosion and a substantial part is transferred into adjacent inland waters, linking terrestrial and aquatic C cycling. However, the net effect on C fluxes between soils, inland waters and atmosphere remains uncertain. In this study, we determined SOC turnover in terrestrial and aquatic environments and indentified its major controls.
A European gradient of agricultural sites was sampled, spanning a wide range soil properties (e.g. texture, aggregation, etc.), SOC quantity and quality. In a 16-week incubation experiment, SOC turnover was determined for conditions reflecting downslope soils or inland waters. Moreover, we studied the impact of labile C inputs (‘priming’) on SOC stability using 13C labeled cellulose. Physical and chemical soil properties and SOC molecular composition were assessed as potential controls on C turnover. SOC deposition in aquatic environments resulted in upto 3.5 times higher C turnover than deposition on downslope soils. Labile C inputs enlarged total CO2 emissions, with the largest increase for aquatic conditions. Solid-state 13C NMR and FT-IR spectroscopy showed broad similarities in SOC molecular composition. Soil and SOC properties could not (yet) fully explain variation in SOC turnover between the sites. However, temporal trends in CO2 emissions clearly differed between downslope soils and inland waters. We established a quantitative model, based on the ten sites of the European gradient, that is capable to describe CO2 emissions for SOC deposited on soils and in inland waters and upon different levels of labile C inputs. Our findings indicate that deposition conditions (soils vs. inland waters) play a crucial role in determining C turnover. Erosion measures preventing deposition in aquatic environments could therefore be an important carbon saving strategy. We envisage that these quantitative results can be used to parameterize biogeochemical models and contribute to better estimates of the impact of soil erosion on C budgets and reduce uncertainties in the link between terrestrial and aquatic C cycling. |
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