Coral reefs are among the most biodiverse ecosystems on Earth, yet they are increasingly threatened. At the heart of coral reef health lies the symbiosis between corals and photosynthetic microalgae that provide essential nutrients to their hosts. This partnership underpins coral reef productivity and resilience, but rising ocean temperatures are causing widespread coral bleaching, driven by the breakdown of this symbiosis. Understanding the factors that influence coral thermal tolerance is critical for protecting reefs, and while algal diversity plays a key role, the potential contributions of their associated bacterial communities remain underexplored. Recent findings suggest that bacteria residing within the specialized cell compartment housing microalgae may influence microalgal functioning, opening new avenues for research into enhancing coral resilience. This project investigates the diversity, functional roles, and potential applications of microalgal-associated microbiomes, aiming to uncover strategies for mitigating the impacts of ocean warming on coral reefs. The project will train many students, equipping them with skills highly sought after in both academic and industrial settings. By fostering a new generation of scientists and advancing our understanding of coral resilience, this work will contribute to the preservation of coral reef ecosystems and their vital ecological and societal benefits. This research will provide a comprehensive analysis of Symbiodini