“My primary research interests include climate and ecological change in the geological past. My research particularly focuses on reconstructing temperature, marine ecology, hydrology, biogeochemical cycles and sea level during periods that were characterized by rapidly increasing, or generally high concentrations of CO₂ in the atmosphere. Together with students and colleagues, I combine micropaleontological and geochemical (both inorganic and organic) techniques to quantify and understand the functioning of planet Earth under ‘greenhouse’ conditions. The results provide the ultimate tool to test the performance of climate and biogeochemical models under such conditions. More recently, I have started to work on the biogeology of an important but understudied group of marine protists, dinoflagellates. The biogeochemistry of dinoflagellates and their fossil remains (dinocysts) is dependent on sea water CO₂ concentrations and pH; a relation we aim to develop into a proxy to reconstruct marine carbon cycling and ocean acidification in the geological past.”