In the depths of the ocean the history of our planet is stored. Creatures from long ago have sunken to the sea floor and today their fossils reveal traces of past events of climate change and mass extinction. AWI biogeochemist Prof. Dr. Jelle Bijma and his colleagues study this archive on the sea floor. With the help of a fossilized, single celled organism - the foraminifera - he wants to find out how life in the ocean has reacted to climatic changes in the past - in order to be able to predict how marine organisms will cope with future changes.