The ocean known for having the most extensive coral reefs is the Pacific Ocean. This vast ocean is home to numerous coral reef systems, including the Great Barrier Reef off the coast of Australia, which is the largest coral reef structure in the world. Coral reefs in the Pacific Ocean are vital for marine biodiversity, supporting thousands of species of fish, invertebrates, and other marine life. These ecosystems also provide essential services to coastal communities, including protection from storms, tourism opportunities, and sources of food. However, the health of these coral reefs is increasingly threatened by climate change, pollution, and overfishing, necessitating conservation efforts.