ENGAGE explores how positive interactions between seagrasses, invertebrates, and microbial communities support seagrass ecosystem functioning and resilience. While these interactions are increasingly recognized as critical, they remain poorly understood in seagrass ecosystems. The project focuses on two model systems: Posidonia oceanica with the sponge Chondrilla nucula, and Cymodocea nodosa with the lucinid bivalve Loripes orbiculatus. Using in situ and mesocosm experiments, ENGAGE tests whether organisms alone or in association can mitigate local and regional stressors, including their interaction with global environmental change. At the same time, the project examines the diversity and function of host-associated and free-living microbes to reveal how microbial processes enhance ecosystem performance and the success of species interactions.