Feedback between climate and ecosystems

The team is working to understand the impact of climate on the evolution of marine microfauna and is benefiting from the analytical development of automated micropalaeontology thanks to projects of lead by Luc Beaufort and Thibault de Garidel. The developments in imaging and image recognition developed for marine microfossils are also applicable to continental microfossils, particularly pollens. This approach, combined with the team's palaeoenvironmental expertise in lacustrine sedimentology and in pollens, phytoliths and diatoms, is being used to reconstruct the living environments of Pliocene hominids in East Africa. These same environments are also described and studied on the basis of the sedimentological evolution of large lakes during the Quaternary.
Savannah and forest environments share a common range in terms of temperature and rainfall. The transition from one ecosystem to another is therefore governed by jumps from one stable threshold to another, in which fire plays a key role. This evolution between these two stable states is at the heart of Julie Aleman's research project (CR CNRS 2022).
The team attaches great importance to an up-to-date approach to the study of marine plankton dynamics at mesocosm and seasonal scales. It will be enhanced by the support of biogeographic genetic data. The action of biological evolution, and even the feedback of this evolution to astronomical and/or climatic forcings, is a key area of research. The evolution of calcareous nannoplankton during the Quaternary is partly guided by cyclical changes in the Earth's orbit, which also modulate the productivity of this plankton and its feedback on the environment and climate. On a larger time scale, the major crises and the appearance of plankton had a fundamental impact on the climate, making these objects an important focus of study in this theme.
The integration and comparison of geochemical, tectonic and biological data with the output of climate simulations led by Yannick Donnadieu has enabled the development of an innovative centre investigating the links between tectonics, climate and biota on long time scales (orbital cycles and beyond). The funding of the DISPERSAL ERC-CoG project (led by Alexis Licht) in 2022 will build on this development. This project proposes an integrative approach (geochemistry, palaeontology, palaeogeography, climate simulations) to understand the climatic and geographical controls on the dispersal of mammals in the past. The project has also increased our analytical resources with the installation of an infrastructure for the analysis of clumped isotopes, a new geochemical approach for the reconstruction of surface temperatures.