Ocean “deoxygenation disrupts marine ecosystems, affects fish stocks and aquaculture and leads to loss of habitat and biodiversity.” (Kiel Declaration 2019). Ocean deoxygenation in the recent past was to a large extent caused by global warming , but residual effects might be linked to enhanced oxygen demand in deeper water layers. Ocean deoxygenation affects the highly dynamic upwelling ecosystems of the Eastern Tropical Atlantic (ETA). These ecosystems are regions of intense oceanic productivity and critical for food supply to millions of people. Establishment of a sustained observation and modelling system for plankton and particle dynamics in the ETA and particularly at the equatorial gateway to the ETA is the major objective of our project.