Carbon dioxide in scree slope deposits: A pathway from atmosphere to pedogenic carbonate

Détails

ID Serval
serval:BIB_0DD469D70F38
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Carbon dioxide in scree slope deposits: A pathway from atmosphere to pedogenic carbonate
Périodique
Geoderma
Auteur(s)
Hasinger O., Spangenberg J., Millière L., Bindschedler S., Cailleau G., Verrecchia E.P.
Statut éditorial
Publié
Date de publication
06/2015
Volume
247-248
Pages
129-139
Langue
anglais
Résumé
A continuum of carbon, from atmospheric CO2 to secondary calcium carbonate, has been studied in a soil associ- ated with scree slope deposits in the Jura Mountains of Switzerland. This approach is based on former studies conducted in other environments. This C continuum includes atmospheric CO2, soil organic matter (SOM), soil CO2, dissolved inorganic carbon (DIC) in soil solutions, and secondary pedogenic carbonate. Soil parameters (pCO2, temperature, pH, Cmin and Corg contents), soil solution chemistry, and isotopic compositions of soil CO2, DIC, carbonate and soil organic matter (δ13CCO2, δ13CDIC, δ13Ccar and δ13CSOM values) have been monitored at different depths (from 20 to 140 cm) over one year. Results demonstrated that the carbon source in secondary carbonate (mainly needle fiber calcite) is related to the dissolved inorganic carbon, which is strongly dependent on soil respiration. The heterotrophic respiration, rather than the limestone parent material, seems to control the pedogenic carbon cycle. The correlation of δ13Corg values with Rock-Eval HI and OI indices demonstrates that, in a soil associated to scree slope deposits, the main process responsible for 13C-enrichment in SOM is related to bac- terial oxidative decarboxylation. Finally, precipitation of secondary calcium carbonate is enhanced by changes in soil pCO2 associated to the convective movement of air masses induced by temperature gradients (heat pump effect) in the highly porous scree slope deposits. The exportation of soil C-leachates from systems such as the one studied in this paper could partially explain the "gap in the European carbon budget" reported by recent studies.
Mots-clé
Pedogenic carbonate, Carbon dioxide, Stable isotopes, Rock-eval pyrolysis, Soil respiration, Soil organic matter
Création de la notice
08/03/2015 19:06
Dernière modification de la notice
03/03/2018 13:40
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