"The general topic of the proposal is the study of the marine carbon cycle and its role in the climate system by driving atmospheric CO2. The investigation of this interaction is vital to understanding the key feedbacks operating in the present-day Earth system. The specific research objectives are to determine at a global scale during key climatic intervals i) the composition and main sources of organic carbon in marine sediments; ii) the relative fluxes of organic carbon from various sources to sediments through time and space; and iii) to relate the relative roles of certain marine carbon cycle processes to changes in atmospheric CO2 concentrations. The approach proposed is to undertake a paleoclimatic study combining geochemical measurements in marine sediments with mathematical simulation experiments, using a 3D climate model with a coupled carbon cycle module. The goal of the project is to obtain quantitative information on marine carbon cycle processes using an interdisciplinary approach. The main reconstruction tools are biomarker proxies, as they provide direct information on the carbon cycle, being carbon based molecules. Three time periods of interest have been selected for the study to represent i) conditions equivalent to present (Holocene); ii) a different response of the climate system to practically the same external forcing (Pliocene); and iii) extreme climatic conditions (LGM). The biomarker data will be contrasted against the carbon model results to seek its validation, and obtain new observational bounds to determine the sensitivity of the Earth’s climate to CO2, with the perspective of improving the Earth system model when used in the assessment of future climate changes. Training will be directed towards acquiring new skills in isotopic techniques to analyze organic matter in marine sediments, and the use of biogeochemical models. Additional skills will be obtained on management, career development, innovation, planning, and change management."