The project will be organized in two subprojects: 1) PATHWAYS focuses on the transfer of solutes to the lagoon and their potential implications to microbiota cycles; 2) INPUT focuses on the identification of solute sources to the coastal aquifer and the water transport mechanisms and bio- and geochemical transformations occurring therein. Results of OPAL will represent a necessary step to improve our understanding of the direct and indirect impacts of human activities on the vulnerability of coastal lagoons that can be extended to other coastal Mediterranean vulnerable areas. We will build a general conceptual model on the major processes involved in the transfer of nutrients and pollutants to coastal lagoons, thereby improving our capacity to remediate contamination and eutrophication processes in coastal lagoons, to prevent the deterioration of these ecosystems and to sustainably manage their goods and services. The project will provide solid and confident information to help public institutions and stakeholders establishing a protocol for adaptation of coastal Mediterranean lagoons to global and climate changes, and to support the integrated management of water resources, ecosystems, and economic resources in intensively used Mediterranean coastal zones.