Cozumel is surrounded by a diverse ecosystem of coral reefs that is home to more than 1,000 marine species. The reefs are primarily found on underwater cliffs, there are also some in coastal lagoons and on sand bars at the north tip of the island. They are part of the much larger Mesoamerican Barrier Reef System which is the second largest reef in the world, stretching over(620 miles. Cozumel's deeper coral reefs were historically famed for their black corals. A huge portion of the reef on the south side of island is sectioned off into the Arrecifes de Cozumel National Park. This park is protected under the Ramsar Convention along with Manglares y Humedales del Norte de Isla Cozumel, they both are included in the UNESCO protected area called Isla Cozumel Biosphere Reserve, Mexico. The site includes the coral reefs on the southern coast of Cozumel. The reefs in Cozumel are made up of hard coral and soft coral.