Postdoctoral position: Climatic and edaphic controls of CO2 isofluxes in soil (France)

Department: The position is based at UMR 1137 Ecologie et Ecophysiologie Forestières (EEF) – Nancy
(France). This department undertakes fundamental and applied research on forest, with strong expertise in ecophysiology and ecology, and belongs to the Cluster of Excellence ”ARBRE” at INRA and University of Lorraine.

Research team: Caroline Plain, Bernard Longdoz, Daniel Epron (scientific advisor).
Context: Forest ecosystem respiration is dominated by soil CO2 efflux (Granier et al. 2000), which come from different biological components (roots, microbes) mobilizing different sources of carbon (recent photosynthate, stored carbohydrates, root exudates, fresh and more or less stabilized organic matter) localized at different depths and thus under different environmental conditions (Epron 2009). Efflux is also the results of physical processes such as diffusion and advection depending on the vertical profile of soil CO2, soil texture and water content. Our understanding of these processes can be improved by measuring the carbon isotope composition of soil CO2 efflux and soil CO2 concentration in different layers at high frequency by laser spectrometry (Marron et al., 2009, Plain et al. 2009, Parent et al. 2013). Indeed, their variations reflect the temporal changes of photosynthetic and  post-photosynthetic fractionation as well as changes in source contribution, and help to better characterize the influence of climatic and edaphic conditions on (i) the vertical distribution of respiratory source, (ii) the intensity of CO2 production and (iii) its transport through the soil profile up to the atmosphere. We have  recently collaborated to the development of a flux-gradient based model that predicted the vertical distribution and the diurnal variations of the production and isotope composition of soil CO2 (Goffin et al. 2014).

Duties: We are seeking a young researcher who will be in charge of understanding the interplay between
production and transport of 13CO2 and 12CO2 in the soil and to analyze their temporal variability at different scales using the flux-gradient based model using a large available data set obtained in the Hesse experimental forest (vertical profile and fluxes of soil and trunk CO2 and d13C-CO2, sapflow, d13C of phloem sap and leaf and root soluble C as well as all the data available at this eddy covariance flux site).
Qualifications: Qualified candidate should be highly motivated and have a PhD degree in Biology or in Soil science with good skills in physics and modelling. Knowledge in stable isotope and forest/agricultural ecosystem functioning would be an advantage but they may be acquired during the first month. Oral and written English are required.
Duration: 12 months, starting Nov 2014 (no later than Dec 1st, 2014).
How to apply? Applicants should submit a CV including a publication list and a short description of previous research, current research interests and other activities of relevance for the position to Daniel Epron (daniel.epron@univ-lorraine.fr). Telephone numbers and e-mail addresses of up to three references should be given. Applications will be accepted until the position is filled.