Job Description
Thesis Subject
Headwater catchments, that is, those of less than 20 km², drain about 70% of continental surfaces and represent the main accessible freshwater resource. Headwater catchments integrate hydrological flows and biogeochemical processes and constitute powerful biogeoreactors that control the water quality of rivers. However, the rivers draining headwater catchments are too numerous to be systematically monitored and protected by legal authorities and therefore remain an aqua incognita.
The first part of the thesis will consist of developing the isotopic analysis of PO4 and verifying that the use of passive sensors to sample P in rivers does not lead to fractionation during absorption or desorption. Once this has been verified, the combination of the concentration of PO4 in the water with its oxygen isotopic ratio will make it possible to quantify the respective proportions of the two main sources using a mass balance calculation. It will then be a question of sampling waters from about thirty headwater catchments of the Lyonnais, Beaujolais, and Brittany regions in France during the low waters of summer and winter to reveal the respective contributions of soils, aquifers, and rivers. It will then involve analyzing the isotopes of nitrates and sulphates as well as those developed for PO4 in the first part of the thesis to infer the recycling capacities of nitrogen and phosphorus as well as denitrification for nitrogen in the selected headwater catchments.
Your Work Environment
The thesis will be carried out in the Laboratory of Ecology of Natural and Anthropized Hydrosystems (LEHNA) at the University of Lyon I on the La Doua campus in Villeurbanne, France. This laboratory has all the laboratory and field infrastructures necessary for carrying out the thesis, which will be co-supervised by Gilles Pinay (Ecologist) at LEHNA and Christophe Lécuyer (Geochemist) at the Geosciences Laboratory of the University of Lyon 1.
Constraints and risks
The research project requires an interest in methodological developments in biogeochemistry and a liking for fieldwork for water sample collection, biogeochemical analysis of water and environmental data management.
Compensation and benefits
Compensation
2300 € gross monthly
Annual leave and RTT
44 jours
Remote Working practice and compensation
Pratique et indemnisation du TT
Transport
Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€
About the offer
| Offer reference | UMR5023-GILPIN-001 |
|---|---|
| CN Section(s) / Research Area | Continental surface and interfaces |
About the CNRS
The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.
