Macroalgae and microbes have been closely associated over long evolutionary periods; however, there is little known about the existing relationships between these organisms. For instance, algal and bacterial synergy may influence varied marine ecosystems from high altitudes to deep seas affecting the physiology and metabolism of macroalgae and microbes (Bacteria and Archaea). My Ph.D. project’s focus is on studying the interaction of microbial communities with each other as well as how do they interact with main macro-algal groups (Phaeophyta, Rhodophyta, and Chlorophyta) within the Red Sea environment.