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Research and teaching centre
environmental geosciences
Research and teaching centre
environmental geosciences

Hydroclimates: from present to past

This area of research focuses on understanding the mechanisms controlling the water cycles in continental and marine environments and on reconstructing past hydroclimates. In recent years, our team has developed an original tool for reconstructing evaporation within the water cycle and, ultimately, past atmospheric relative humidity, a key parameter of the climate system (ANR project HUMI-17, supported by Anne Alexandre). This method is based on the analysis of the triple isotopic composition of oxygen (17O-excess), whose variation processes within the different compartments of the water cycle (vapour, precipitation, soils, plants) and phytoliths have been defined in controlled, natural and modelled environments. The recent DIAT-17 (LEFE-INSU, 2022-2023), supported by Anne Alexandre and Florence SylvestreThe aim of this project is to assess the potential of 17O-excess analysis of diatoms for reconstructing the extent of evaporation from lake waters. The project will ANR PAST-17funded in 2022 and supported by Anne AlexandreIt uses the calibrations developed in previous projects to reconstruct past hydroclimates on different timescales, in the intertropical and Mediterranean zones, in interaction with changes in vegetation and the impact of mankind. This research direction has been strengthened by the recent recruitment of Julie Aleman (CR CNRS, 2022), an ecologist who uses the 17O-excess of phytoliths to decouple the signal of vegetation, climate and man in Quaternary archives.
The WAO project (AFALULA funding), supported by Pierre DeschampsThe aim of this project is to improve understanding of the hydrological functioning of the Saq aquifer in the Al Ula region (Saudi Arabia), in order to move towards sustainable management of this resource, which is essential for the socio-economic and agricultural development of this oasis. This theme of hydrological cycles in semi-arid to arid zones is also being reinforced by the setting up of the LMI Viabeleaux (2020-2024) in Chad, supported by Florence Sylvestre.

Projects

  • 2023-2027 : ANR PAST-17
    Quantitative reconstruction of past hydroclimates: the triple oxygen isotopic composition (17O-excess) of biogenic silica in perspective
  • 2022-2023 : INSU LEFE/IMAGO DIAT-17
    Excess 17O in diatoms: towards a new hydroclimatic marker 
  • 2020-2024 : LMI VIABELEAUX
    Sustainability of socio-ecosystems in the Sahel in the face of global change
  • 2021-2022: IMAGO LEFE IndSo : Past El Niño Modes in Indian Ocean Subtropics

  • 2017-2022: ANR HUMI-17, Dynamic of continental atmospheric humidity and vegetation response:new insights from the triple isotopic composition of oxygen