The Mid-Pleistocene Transition (approximately 1.2–0.7 Ma) marks a major shift in the climate system,
the mechanisms of which remain debated. One proposed explanation involves a decline in
atmospheric CO₂ concentrations. The Beyond EPICA ice core provides a unique opportunity to
investigate this period. Preliminary results reveal a CO₂ minimum around 0.9 Ma ago, coinciding with
changes in ocean circulation, carbonate δ¹³C and deep-ocean oxygenation.
This Master’s project aims to improve our understanding of the interactions between the biosphere,
the carbon and oxygen cycles and climate during this event, while distinguishing the biological
(photosynthesis) and physical (ocean circulation) processes underlying the observed changes.
Approximately 100 measurements of atmospheric Δ¹⁷O of O₂, a tracer of global biospheric productivity,
will be performed on the air trapped in the Beyond EPICA ice core. Combined with box-model
simulations, these measurements will help explore plausible scenarios for changes in global biospheric
productivity. A compilation of data from ice cores and marine sediment records will complement this
approach to identify mechanisms that could explain the observed changes.
The project will combine laboratory-based analytical work, box modelling and the study of
paleoclimate archives. It will be conducted jointly by the GLACIO team at the LSCE and the GEOPS
laboratory, in collaboration with other LSCE teams and international partners involved in the Beyond
EPICA programme.