Life originated in the sea, and the oceans harbor the greatest species diversity on earth, which in turn drives biogeochemical cycles and ecosystem services. At the same time, marine ecosystems are increasingly exposed to multiple stressors such as warming, ocean acidification, de-oxygenation, species invasions and the spread of pathogens. Global change research has so far mainly focused on the short-term physiological and ecological consequences of anthropogenic disturbance. The potential of populations and communities to adapt rapidly to global change is only slowly gaining momentum, and has rarely been considered in modeling projections. This is a major knowledge gap for future ocean scenarios and biogeochemical models. Rapidly accumulating evidence indicates that eco-evolutionary feedbacks determine biotic interactions and hence the functioning of ecosystems over time scales similar to present-day anthropogenic disturbances. At the same time, the rapid progress in -omic techniques enable the study of fundamental molecular genetic principles of various traits that underlie important ecosystem functions in many non-model marine species. In an effort to unite research in the Cluster topics Ocean Innovation and Evolving Ocean, projects focused on co-evolution among pathogenic or commensal microbes and their hosts as well as the role of such interactions in adaptation to global change are welcome.