Europe’s deep-ocean margin stretches over a distance of 15,000 km along the Atlantic Ocean from the Arctic to the Iberian margin and from western to eastern Mediterranean, and to the Black Sea. The margin extends from the shelf edge at about 200 m depth until about 4000 m depth where the abyssal plain or oceanic basins begin, and covers three million square kilometers, an area about one-third of that covered by Europe’s landmass. Most of this deep-ocean frontier lies within Europe’s Exclusive Economic Zone (EEZ) and is therefore of direct interest for the exploitation of biological, energy, and mineral resources. A major European policy aim is to develop these resources in an ecologically sustainable manner. This requires a profound knowledge of the structure and dynamics of ocean margin ecosystems incorporating a wide variety of complex environments, such as deep-sea corals, cold seeps, and canyons. The knowledge required must be generated in an integrated way that ties research on biodiversity and biological processes intimately to the physical factors that control ecosystems (geology, sedimentology, physical oceanography, biogeochemistry). In addition, it is important to set present-day ecosystems in an historical framework by studying the sediment record to determine long-term environmental changes and the potential response of ecosystems to global change over decadal to millennial scales. Changes due to large-scale natural forcing (e.g., climate oscillations, sea-level change) or to more local human effects (e.g., resource exploitation, inputs of pollutants and nutrients) must be distinguished from each other before man’s activities make this distinction impossible (Danovaro et al., 2001). In some areas, notably deep-water coral reefs, man’s impact on the environment has already been considerable (Freiwald et al., 2004).