Coral reefs are underwater ecosystems formed by the accumulation of calcium carbonate skeletons of coral polyps. They are known for their biodiversity, serving as habitats for various marine life. Coral polyps, tiny organisms related to jellyfish, build stony structures that create complex formations. Coral reefs are crucial for fisheries, protect coastlines, and contribute to tourism. However, they face threats such as climate change, overfishing, and pollution, necessitating conservation efforts for their preservation. #ocean #coralreef #greatbarrierreef