Two are the objectives of this project, namely the description of seasonal variability of the benthic and pelagic systems in a semiconfined environment such as the Gulf of Trieste, that is subject to seasonally-variable river contributions; and the understanding of the processes leading to the production of dissolved organic matter (DOM), whose aggregation produces gelatinous macro aggregates. The activities carried out include the monitoring of abiotic and biotic characteristics of benthic and pelagic systems, the experimental estimate of carbon flows, experiments in mesocosms on the bacterial and viral components, and the creation of a database and of the Geographic Information System (GIS) on paper and multimedia supports. The main scientific objectives of the project are the definition of the trophic state of the system and its fluctuations at short time intervals (continuously for 5 years, so as to outline the interannual fluctuations in order to detect the main physical forcing agents), the detection of the factors that trigger off the main anomalies of the system (the ones that lead to the onset of detrimental phenomena or that prevent the proper fruition of environmental resources) and, lastly, the project aims at quantifying the carbon flows within the benthic and pelagic systems. The analyses also regard the definition of the biological bearing capacity of the system, the assessment of the trophic and functional relations between the benthic and pelagic systems, the isolation and the detection of the main producers of dissolved jelly-like matter, the experimental detection of physical, chemical and/or biological factors that engender the production of jelly-like matter, the definition of the viral component role in the onset of anomalies observed in the system and the modelling of the main biogeochemical processes that are typical of the system.