As part of the Helmholtz Earth system observation programme MOSES, researchers are planning to investigate extremely low-oxygen eddies in the tropical Atlantic until Christmas. On board are also researchers from the MARUM - Center for Marine Environmental Sciences. By now, the research vessel METEOR has left the port of Mindelo. A research aircraft will support the search from the air. Long before leaving, autonomous devices around the Cape Verde islands were scouting the ocean for for eddies suitable for study.