Carbonate chemistry, carbonate cycle and climate change

Among the most important challenges remaining to be addressed by Quaternary paleoceanographers is the mechanism responsible for lowering pCO₂ during the Last Glacial Maximum (LGM) and possible feedback mechanisms with climate change. Our main objective is to use a multi-proxy approach (Table 1) in order to reconstruct the oceanic carbonate chemistry over the past 130,000 years. In combination with numerical models this will allow us to 1) distinguish the mechanisms that control the operation of the oceanic carbon cycle, 2) identify water masses as sinks or sources of atmospheric CO₂ and hence, 3) better constrain the role and the impact of the carbon cycle on climate oscillations. Knowledge of the nature and amplitude of natural fluctuations in the past are a precondition to assess the stability of modern subsystems and their potential range of variations in the future.