Project aims to identify key components of the trophic web of marine ecosystem in the northern adriatic sea, and to provide a first assessment of energy fluxes among such compartments. Since in this area the dynamic of the lower levels of the food web (including microbial activity) has been already extensively studied, particular attention is devoted to explore the ecological role of small ... pelagic fishes (anchovies and sardines) and mussels, with analysis which include the determination of the food daily ratio in different moments of the year and the identification of bioenergetic models. However the research includes also a biogeochemical characterization of water column and upper sediment, the identification of abundance and composition of plankton communities, the determination of primary production, respiration, bacterial activity, and the analysis of space and time variability of major water quality parameters. The above will be integrated and framed in the context of pre-existing knowledge, also by using purposely developed numerical models. Scenario analysis might be performed to investigate possible responses of the ecosystem to variations in the environment (global changes, introduction alien species).