Studying climate and biota in past oceans to project the future
Modern oceans are subject to warming, acidification and decreasing oxygen concentrations due to human actions, which will likely have major effect on biology. We focus on the reconstruction of past ecosystems and climates based on the study of microfossils from ocean floor sediments, notably fossils of dinoflagellates, major components of the ocean’s phytoplankton. Our focus on time periods in the geological past that saw similar changes as today, enables us to use information from present and past oceans to elucidate how future oceans will change.
Humans inject massive amounts of CO2 into the atmosphere, which causes warming of the atmosphere and oceans. Moreover, a large portion of the CO2 dissolves in ocean waters, resulting in acidification. Finally, the addition of nutrients to coastal oceans, as well as climate change ultimately leads to a reduction in oxygen content of subsurface ocean water. Warming, acidification and anoxia are major threats to life in future oceans.
Reconstructing past climate and ecology
Crucially, warming, acidification and anoxia are not unique to the present. Specific periods in the geological past offer the opportunity to evaluate the consequences. The Marine Palynology and Paleoceanography group therefore aims to reconstruct climate and marine ecology during such periods of global change.
Paleoecology of dinoflagellates
Our core business is the (paleo)ecology of dinoflagellates, single celled plankton with an enormous ecological variety. The organic dinocysts produced by many dinoflagellates preserve in ocean sediments. By palynological processing in the Laboratory of Palaeobotany and Palynology in the Geolab, these dinocysts can be isolated from sediments to be studied using microscopy. This way, the assemblages of dinoflagellates that once lived in the oceans can be reconstructed, leading to powerful insights into paleo-ecosystem functioning.
We combine palynology with geochemical techniques, notably the study of organic biomarkers in collaboration with the organic geochemistry group, and paleoclimate and carbon cycle modeling with colleagues in Utrecht and elsewehere. The ultimate aim is to understand variations in the state of System Earth, and particularly the role of the ocean, including its biology, physics, and chemistry on various temporal and spatial scales, in the past, present and future.