The PHYBIO oceanographic cruises constitute a central activity of the on-board training within the framework of 'Sciences de la mer' master's degree from OSU-PYTHEAS at Aix-Marseille University (AMU). The goal of this cruise is to allow Master 1 students to actually do oceanography as it is done by oceanographers in the field. They cover in an educational way all the aspects of a cruise: planning, collection of samples at sea, deployment of instruments responding to a predefined strategy, analysis of samples in the laboratory, writing of a report and communication of results. The participation to an oceanographic cruise allows students to be "confronted to the field, while making use of the skills acquired in various teaching units by applying them to a concrete case: a coupled study of physical oceanography and biogeochemistry off the bay of Marseille at the interface between land and sea.