"Major questions about the functioning of marine ecosystems on the continental margin concern their interrelationship/dependence on the natural drivers (physical and geological processes), as they are strongly physically and geologically mediated and potentially affected by human and climate change perturbations. Indeed, recent studies in the Western Mediterranean have demonstrated that flows triggered by dense shelf water cascading transport large amounts of water and sediment from the shelf to the deep basin. Cascading waters directly affect the functioning of the deep ecosystem by providing a fast way of fuelling highly nutritive, fresh organic matter to the deep, transforming brusquely authentic biological deserts in real oases. In addition, water and sediments transported from the coastal zone can act as preferential transfer vectors for contaminants, which may affect negatively marine ecosystems. Therefore, this highly energetic mechanism of flushing of dense shelf waters may be crucial to control benthic community structure, but little is now at the moment.The main objective of the ARISTEUS (Environmental VARIableS RegulaTing DivErsity and FaUnal DistributionS in Canyon and Lower Slope Ecosystems of the Western Mediterranean) project is to carry out multidisciplinary research in canyon and lower slope ecosystems of the Western Mediterranean aimed at i) characterize the physical (water column current regime and near-bed current regime) and biogeochemical (sediment transport, seabed composition, input of particulate organic matter) factors regulating diversity and faunal distributions, and ii) determine how do these environmental variables influence biological communities (establishment of the relationships between the abiotic factors and the spatial and temporal structure of meio-, macro- and megafauna populations) with special attention to the deep-sea living resource Aristeus antennatus."