Hydroclimates: from present to past

This line of research focuses on understanding the mechanisms controlling water cycles in continental and marine environments and reconstruction of past hydroclimates. Over the last few years, our team has developed a original reconstruction tool of theevaporation within the water cycle and, in finethePast atmospheric relative humiditya key parameter of the climate system (ANR HUMI-17 project, supported by Anne Alexandre). This method is based on theanalysis 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 the phytoliths have been defined in controlled, natural and modelled environments. The recent DIAT-17 (LEFE-INSU, 2022-2023), supported by Anne Alexandre and Florence Sylvestreis to assess the potential of 17O-diatom processs to reconstitute theamplitude of lake water evaporation. The project ANR PAST-17funded in 2022 and supported by Anne Alexandreuses the calibrations resulting from previous projects to reconstitute the past hydroclimates on different time scales, by Intertropical and Mediterranean zonein interaction with changes in vegetation and the impact of man. 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 for decoupling the signal from vegetation, climate and people in the Quaternary archives.
The WAO project (AFALULA funding), supported by Pierre Deschampsaims to improve understanding of hydrological functioning of the Saq aquifer in the Al Ula region (Saudi Arabia) in order to move towards a sustainable management of this essential resource for the socio-economic and agricultural development of this oasis. This theme of hydrological cycles in semi-arid to arid zones is also reinforced by the setting up of the LMI Viabeleaux (2020-2024) at Chadsupported by Florence Sylvestre.