Diversity and reactivity of organic matter in Morvan forest soils: evolution of soil respiration and control factors under climatic constraints

Started in october 2021

Funding: doctoral grant

Supervisor: Jean Lévêque ; cosupervisor: Olivier Mathieu

Abstract

The impact of global warming on the biogeochemical carbon cycle is a major issue, especially its effects on soil carbon stocks and fluxes and on forest soils in particular. Currently, there is no clear understanding of the link between forest management, soil and organic matter diversity and their effects on the sensitivity of soil respiration to increased temperature. This relationship between temperature and C flux is dependent on multiple biotic and abiotic factors. The objectives of this project are to assess the diversity of organic matter in Morvan forest soils according to their management methods, and to assess the reactivity of these organic materials through the sensitivity of soil respiration to climatic constraints. To answer, a mosaic of forest sites representative of the diversity of soils and uses will be sampled within the Massif du Morvan. A forest site in the plain will also be studied to add a contrasting pedo-climatic situation. The characterization of the SOM of the sites will be carried out via spectroscopic and spectrometric techniques (∂13C, UV-Vis, Py-GC-MS, EGA) on different compartments (stable vs. labile). The sensitivity of soil respiration to the temperature factor (Q10) will be determined from incubations. At some sites, laboratory measurements will be supplemented by in situ measurements of CO2 fluxes and monitoring of soil temperature and humidity. All of these results continue to refine the link between the management mode, type of cover and diversity of OM, as well as to assess the impact of these factors on respiration in a context of rising temperature.

Keywords

soil organic matter, forests, carbon stocks, soil respiration, carbon dioxide, climatic constraints

Thesis advisory panel

Sylvie Dousset (université de Lorraine, département de géosciences, LIEC)
Heike Knicker (Department of Biogeochemistry Plant and Microbial Ecology, IRNAS-CSIC)

extrait:

lien_externe:

titre:

Diversité et réactivité des matières organiques des sols forestiers du Morvan : évolution de la respiration des sols et facteurs de contrôle sous contrainte climatique

date_de_debut_these:

octobre 2021

nom:

Bonnefoy-Claudet

date_de_debut_these_numerique:

202110

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kc_raw_content:

Diversity and reactivity of organic matter in Morvan forest soils: evolution of soil respiration and control factors under climatic constraints

Started in october 2021

Funding: doctoral grant

Supervisor: Jean Lévêque ; cosupervisor: Olivier Mathieu

 

Abstract

The impact of global warming on the biogeochemical carbon cycle is a major issue, especially its effects on soil carbon stocks and fluxes and on forest soils in particular. Currently, there is no clear understanding of the link between forest management, soil and organic matter diversity and their effects on the sensitivity of soil respiration to increased temperature. This relationship between temperature and C flux is dependent on multiple biotic and abiotic factors. The objectives of this project are to assess the diversity of organic matter in Morvan forest soils according to their management methods, and to assess the reactivity of these organic materials through the sensitivity of soil respiration to climatic constraints. To answer, a mosaic of forest sites representative of the diversity of soils and uses will be sampled within the Massif du Morvan. A forest site in the plain will also be studied to add a contrasting pedo-climatic situation. The characterization of the SOM of the sites will be carried out via spectroscopic and spectrometric techniques (∂13C, UV-Vis, Py-GC-MS, EGA) on different compartments (stable vs. labile). The sensitivity of soil respiration to the temperature factor (Q10) will be determined from incubations. At some sites, laboratory measurements will be supplemented by in situ measurements of CO2 fluxes and monitoring of soil temperature and humidity. All of these results continue to refine the link between the management mode, type of cover and diversity of OM, as well as to assess the impact of these factors on respiration in a context of rising temperature.

 

Keywords

soil organic matter, forests, carbon stocks, soil respiration, carbon dioxide, climatic constraints

 

Thesis advisory panel

Sylvie Dousset (université de Lorraine, département de géosciences, LIEC)
Heike Knicker (Department of Biogeochemistry Plant and Microbial Ecology, IRNAS-CSIC)