This project aims to understand how microbes, the first responders to changes in environment, react to changes in salinity in coastal and open-sea areas, including ecologically sensitive areas where salinity is higher than usual. As the Mediterranean warms and becomes more saline due to climate change, altered water circulation and extended stratification-layered water column periods challenge Adriatic ecosystems. This project investigates the resulting microbial community shifts, filling a key gap in our understanding of response to these challenging environmental stressors. To address this, we will apply state-of-the-art methods to Adriatic Sea, supported by an expanded research collaboration with partners in Czechia and Germany. We aim to identify responses of key microbial players and assess the vulnerability and resilience of bacteria to ongoing changes in salinity. We will provide initial state of microbial richness and functional diversity in studied ecologically sensitive zones, aligning closely with the goals of IUCN Microbial Conservation Specialist Group and helping to integrate microbes, as base of food web, into future conservation assessments and monitoring programmes. To our knowledge, this is pioneering study of its kind in the area.