The project aims to reconstruct deep water carbonate ion contents at millennial timescales using high sedimentation cores from the Atlantic Ocean. Foraminiferal oxygen isotopes and B/Ca proxies will be used for reconstructions. The data will used to investigate past ocean circulation and carbon cycle changes in the deep Atlantic. These will then be used to evaluate the ocean's role in affecting past atmospheric CO2 and climate variations. When necessary, models will be used to investigate mechanisms controlling past ocean circulation and carbon cycle.