Margaux Brandon

Margaux Brandon

Doctoral / Post-doctoral researcher

THESIS SUBJECT

The major changes of biological productivity during the Quaternary and their impacts on the carbon and oxygen cycles.

THESIS SUMMARY

The aim of my thesis is to reconstruct the past changes in biological productivity and to estimate their contribution on atmospheric O2 and CO2 variations over the past 800 ka using empirical approaches combined with climate model outputs. Measurements of Δ17O of O2 in bubbles of EDC ice core (Antarctica) are performed to reconstruct the global biosphere oxygen fluxes. Geochemical (TOC, CaCO3, XRF) and micropaleontological (coccoliths) analyses are done on marine sediments to trace back the changes in biological pump efficiency of the last 800 ka in the Indian sector of the Southern Ocean. Lastly, outputs of vegetation and oceanic biogeochemistry models are used to facilitate the comparison with empirical data acquired. A special attention is given to Terminations I and V.

SUPERVISORS

Thesis director : Giuseppe Siani (GEOPS)

Co-supervisors : Stéphanie Duchamp-Alphonse (GEOPS), Amaëlle Landais (LSCE) and Masa Kageyama (LSCE)

FUNDING

IDI-IDEX Doctoral contract

Margaux Brandon sur le Marion Dufresne