This document summaries my research for the past 18 years at the university of Zurich and the Ecole normale supérieure. It is based on three main concepts: a scientific view on the persistence of the organic matter in the ecosystems, a holistic approach on how to study plant-soil systems, and a general desire to study such complex systems with transdisciplinarity. In a nutshell, my main research questions are “how much” carbon is there is the terrestrial ecosystems, and “how fast” they transfer from one compartment to another. The main focusses of my work are the pyrogenic carbon and the root-derived carbon in the terrestrial ecosystems. The pyrogenic carbon is the remaining organic fraction of biomass after exposed to heat and fire. On this topic, I was particularly interested in the method to describe it quantitatively and qualitatively, its amount in the ecosystems, at local and global scales, as well as the mechanisms describing its distribution. I also worked on a nature based solution related to this pyrogenic carbon, namely the biochar. Regarding the plant-soil systems and the focus on root-derived carbon, I am interested in how this carbon can be studied from different time and space perspectives, with a focus on the quantity of carbon that flows through the roots and the rhizosphere during the life of the plant, and during its decomposition later on. During these studies, I came across the observation that the effect of roots on the native soil organic matter may be as important as the root-derived carbon itself. This work is globally a playdoyer for experimental science, associated to other disciplines, to study ecosystem complexity.

Lieu
École normale supérieure – PSL
Amphithéâtre Jaurès
29 rue d’Ulm – 75005 Paris

Visio
https://cnrs.zoom.us/j/96140643704?pwd=2OGbMJ1ZVFgz8jHHIWQZ3U44bZFGZH.1

• Naoise Nunan – Dr., CNRS IEES Rapporteur
• Philippe Hinsinger – Dr., INRAE Eco&Sols Rapporteur
• Stefan Doerr – Prof. Dr., University of Swansea Rapporteur
• Claire Chenu – Prof. Dr., INRAE Ecosys Examinateur
• Caroline Masiello – Prof. Dr., Rice university Examinateur
• Heike Knicker – Prof. Dr., CSIC Examinateur
• Philippa Ascough – Prof. Dr., SUERC Examinateur
• Denis Angers – Dr., Université de Laval Examinateur
• Pierre Barré – Dr., CNRS Laboratoire géologie ENS Correspondant