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Theses

Impact d’un réchauffement climatique sur le fonctionnement de la sphagnosphère : relations polyphenols-communautés microbiennes

Abstract : Carbon stocks of Sphagnum-peatlands are likely to be altered by climate warming due to important changes in “Sphagnum-microorganisms” relationships which are responsible for carbon sequestration. The objectives of the thesis are (1) to identify the chemical interactions between Sphagnum-polyphenols and Sphagnum associated microbial communities and (2) to understand the impact of warming on these relationships.An experimental design using Open-Top-Chambers (OTC) was used to simulate an increase of air temperatures (+1°C) on a peatland situated in Jura Mountains (Frasne, 25). Temperature increase induced a modification of the microbial food web with an increase of the biomass of bacteria and a strong decrease of the biomass of top-predators (-70%), i.e. testate amoebae. Warming also induced a decrease of Sphagnum-polyphenols, diminishing their inhibitory effect on microbial communities. In parallel, an increase of phenoloxidase enzymatic activities was recorded in OTC. Climate warming thus modified polyphenol-phenoloxidase interplay, two crucial components of carbon cycle in peatlands. Warming effects on the different components – i.e. polyphenols, phenoloxidases, microbial food web – induced a modification of Sphagnum-microbial communities interplay, favoring carbon and nutrient recycling, which could alter peatland functioning in long-term.
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  • HAL Id : tel-00802903, version 1

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Vincent Jassey. Impact d’un réchauffement climatique sur le fonctionnement de la sphagnosphère : relations polyphenols-communautés microbiennes. Biologie végétale. Université de Franche-Comté, 2011. Français. ⟨NNT : 2011BESA2011⟩. ⟨tel-00802903⟩

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