Soil Science and Biogeochemistry


Peatlands cover a small fraction of the continents (3%), but they contain a huge amount of carbon (C), making these systems important to take into account in global C studies. As these ecosystems are under global (climate change) and local (mainly drainage) threat, they could switch from C sink to source function, with potential reinforcing effect on climate change (positive feedback). Considering their important C content, C fluxes (CO2, CH4, which are greenhouse gases-GHG) in such systems have to be monitored to testify how they respond to global and local disturbances. Furthermore, the determinisms of these fluxes have to be understood to be able to incorporate peatlands in global earth models. The peatland biogeochemistry team regrouping scientists from ISTO and LPC2E is dedicated to understand C dynamics in peatlands, through monitoring, experimental and modelling activities.

One of the main current research projects of the team is the setting up of a Platform to study GHG Exchange between Soils and the Atmosphere in peatland (PESAt). Specifically, it consists in implementing 4 different operations: 1) eddy covariance station in La Guette peatland, 2) small automatic chamber, 3) made to measure high automatic chambers for tall vegetation, 4) gradient method equipment. This platform will help to understand the determinisms of the GHG fluxes at different scales of space and time. A fraction or the entire amount of these gases is produced by microbial communities in the soil. The response of GHG fluxes to the main factors (temperature, oxygen availability, plant communities) is actually dependent on the response of the microorganisms in the soil in terms of quantity (biomass) and characteristics (community composition). The microbial scale is not in the scope of this platform. The successful candidate will help to fill this gap, allowing a finer understanding of microbial processes behind GHGs production and emission and thus the response of peatlands to global change.