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Cycle biogéochimique du silicium dans les environnements superficiels continentaux : Impact des plantes terrestres

Abstract : The aim of this experimental study is, in a first time, the characterization of reactivity and physico-chemical properties of micrometrics biogenic opals called phytoliths for several terrestrial plants species from differents environments. In this regard, several complementary technics were used, such as solubility measurements, dissolution kinetics, electrophoretic measurements and potentiometric titrations, that allowed better constraining the acid-base surface reactions and thermodynamic and kinetic parameters of phytoliths interactions with aqueous solutions. In the second part of this work, we studied terrestrial plant litter interaction with aqueous solutions via litter degradation experiments in batch and mixed-flow reactors. Obtained results demonstrated high aqueous reactivity of both phytoliths and plant litter that exceeds dissolution rate of common soil minerals by 1-2 orders of magnitude. Quantitative evaluation of plant litter and phytoliths control on Si release from these solid reservoirs demonstrates strong possible impact of plants on biogeochemical cycle of silicon in almost all terrestrial environments.
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https://tel.archives-ouvertes.fr/tel-00179740
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Submitted on : Tuesday, October 16, 2007 - 3:09:42 PM
Last modification on : Monday, April 5, 2021 - 2:26:09 PM
Long-term archiving on: : Friday, November 25, 2016 - 5:11:07 PM

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  • HAL Id : tel-00179740, version 1

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Fabrice Fraysse. Cycle biogéochimique du silicium dans les environnements superficiels continentaux : Impact des plantes terrestres. Autre. Université Paul Sabatier - Toulouse III, 2007. Français. ⟨tel-00179740⟩

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