The complex microbial symbiosis in marine species is examined in this study, with particular attention paid to the variety of interactions that occur between bacteria and hosts in coral reefs, deep-sea vents, and coastal environments. We demonstrate the ecological relevance of these symbiotic relationships including their involvement in nutrient cycle, host health, and ecosystem resilience by looking at a broad variety of research. Microbial symbionts in coral reefs help to keep the reef resilient to environmental stresses and healthy. Chemoautotrophic bacteria maintain diverse vent communities at deep-sea vents by supporting primary production in the absence of sunshine. Microbial interactions affect the well-being and productivity of many marine creatures in coastal settings. The significance of comprehending marine microbial symbiosis for the preservation and administration of marine environments is emphasised by this review.