Elementor #21793

Numerous paleontological databases (PBDB, …) reveal several biodiversity crises resulting in the extinction of many species but also in major perturbations of the climate and carbon cycle. If biosphere, biogeochemical cycles and climate are undoubtedly linked on the geological time scale, it is still very difficult to link the geochemical message to paleontological data. Understanding how the ocean biosphere and terrestrial climate interacted on the geological time scale thus remains a major challenge in Earth sciences. Progress in solving this problem requires the integration of biosphere-environment interactions into numerical models describing the long-term evolution of biogeochemical cycles and climate. However, numerical models that simulate the long-term evolution of climate and the carbon cycle assimilate the biosphere to its biomass, which is either forced by the inversion of the δ13C signal measured on sedimentary carbonates, or modelled in a totally deterministic way by making it only dependent on the available nutrient fluxes. The objective of this thesis is to consider the biosphere as a whole by integrating its biological complexity with the aim of studying the great biological crises of the Phanerozoic with the working hypothesis of testing the effects of large volcanic outpourings (traps).