The Adriatic Sea, known for its diverse marine ecosystems and unique ecological dynamics, is facing significant changes due to climate-induced oligotrophication. A high-resolution biogeochemical model, developed for the entire basin, was used to simulate the impacts of projected climate changes under the RCP8.5 scenario from 1992 to 2050. The model, with a horizontal resolution of about 2 km and 120 vertical levels, evaluated changes in ecoregions characterized by different trophic conditions using a k-medoid classification technique. The results indicate a generalized oligotrophication of the basin, particularly in the northern estuarine areas, driven by a substantial decrease in river discharge from the Po Plain. This scenario, combined with ongoing warming, salinization, and acidification, raises concerns about the long-term resilience of the Northern Adriatic food web, which has evolved to thrive in high trophic conditions. The study provides stakeholders with a tool to understand how potential long-term decreases in river discharge could affect the marine ecosystem and its goods and services in the future. The projected changes include a sharp decline in nutrient-rich conditions, reduced biological activity, and increased stratification, highlighting the need for adaptive strategies to mitigate potential ecological and economic impacts.The Adriatic Sea, known for its diverse marine ecosystems and unique ecological dynamics, is facing significant changes due to climate-induced oligotrophication. A high-resolution biogeochemical model, developed for the entire basin, was used to simulate the impacts of projected climate changes under the RCP8.5 scenario from 1992 to 2050. The model, with a horizontal resolution of about 2 km and 120 vertical levels, evaluated changes in ecoregions characterized by different trophic conditions using a k-medoid classification technique. The results indicate a generalized oligotrophication of the basin, particularly in the northern estuarine areas, driven by a substantial decrease in river discharge from the Po Plain. This scenario, combined with ongoing warming, salinization, and acidification, raises concerns about the long-term resilience of the Northern Adriatic food web, which has evolved to thrive in high trophic conditions. The study provides stakeholders with a tool to understand how potential long-term decreases in river discharge could affect the marine ecosystem and its goods and services in the future. The projected changes include a sharp decline in nutrient-rich conditions, reduced biological activity, and increased stratification, highlighting the need for adaptive strategies to mitigate potential ecological and economic impacts.