%0 Journal Article
%9 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES
%A Hazera, J.
%A Kowalewski, I.
%A Sebag, D.
%A Verrecchia, E.
%A Ravelojaona, H.
%A Chevallier, Tiphaine
%T Coupling infrared isotopic gas analysis and thermal ramped analysis to characterise soil organic and inorganic carbon
%D 2025
%L fdi:010092695
%G ENG
%J European Journal of Soil Science
%@ 1351-0754
%K biogenic carbonate ; calcareous soils ; isotopic signature ; lithogenic ; carbonate ; Mediterranean soils
%K FRANCE ; ZONE MEDITERRANEENNE
%M ISI:001408449100001
%N 1
%P e70041 [5 ]
%R 10.1111/ejss.70041
%U https://www.documentation.ird.fr/hor/fdi:010092695
%> https://horizon.documentation.ird.fr/exl-doc/pleins_textes/2025-03/010092695.pdf
%V 76
%W Horizon (IRD)
%X Studying the soil organic and inorganic carbon (SOC and SIC) dynamics is essential to assess the carbon (C) sequestration potential of calcareous soils. Isotopic signatures (delta C-13) are used to assess the C origin of SOC or SIC. However, as measuring SOC and SIC contents, measuring delta C-13(SOC) and delta C-13(SIC) on a non-pretreated aliquot remains a challenge. Thermal analyses, like the Rock-Eval (RE) analysis, are promising to quantify SOC and SIC in a single analysis, but, to our knowledge, no development was conducted to assess delta C-13(SOC) and delta C-13(SIC). We coupled a RE device to an isotopic gas analyser (Picarro) to continuously measure delta C-13(CO2) and approach delta C-13(SOC) and delta C-13(SIC). We hypothesised that different carbonate mineralogies and/or crystal sizes in SIC involve fluctuations of the delta C-13(CO2). Two calcareous soils, a lithogenic (calcite) and a biogenic (snail shell) carbonate, and five calcite/shell mixes were analysed with the RE-Picarro setup. Two distinct delta C-13(CO2) values were obtained before and after 650 degrees C and were consistent with the delta C-13(SOC) and delta C-13(SIC) obtained by EA-IRMS. The fluctuations of delta C-13(CO2) above 650 degrees C were higher with calcite/shell mixes than with pure carbonates. A delta C-13(CO2) fluctuation > +/- 0.2 parts per thousand could be a pertinent indicator to detect mixes of carbonate with different delta C-13 in soils. The RE-Picarro setup is promising to assess SOC and SIC contents, delta C-13(SOC) and delta C-13(SIC) and detect mixes of carbonate with different origin on a non-pretreated aliquot. Development is needed (i) on more soil and carbonate samples and (ii) to improve the precision and accuracy of the RE-Picarro setup.
%$ 068