show Abstracthide AbstractHot springs, often characterized by high temperatures and unique chemical compositions, create extreme environments that are challenging for many organisms to survive in. Aquatic ecosystems are shaped by complicated interactions between photosynthetic prokaryotes and heterotrophic bacteria within their phycosphere. Hence, monitoring and understanding the dynamics of these microorganisms in aquatic systems are crucial for maintaining ecosystem health. I this work, the structural diversity of bacterial communities associated with cyanobacterial cultures collected from the hydrothermal pool in the Ksar Ghilane oasis in Tunisia was investigated using High-throughput sequencing. The obtained results highlight the diversity of cyanosphere Cyanobacteria-mediated and the complexity of interactions occurring between autotrophs and heterotrophs in springs.