Recent research on the bioaccumulation of organic and trace element contaminants along trophic food webs suggests that plankton plays a central role as a 'biological pump' for pollutants. The MERITE-HIPPOCAMPE project (oceanographic cruise in April- May 2019) aims at studying the interactions between plankton and contaminants (metallic, organic plastics) at atmosphere/water/biota interfaces via a North-South trans-Mediterranean approach in contrasted areas (primary production, fishing zones, ecoregions, polluted bays). The target contaminants are on the lists of priority pollutants and substances of Regional Conventions (OSPAR) and EU directives (WFD, MSF). The expected results are to provide a better understanding of the transfer processes of contaminants from water to the first pelagic trophic levels