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- A coral reef may build up to the surface of the tropical ocean .
- Beyond the coral reef the open sea is dark blue
- Look , that ship is hanging up on a coral reef
- Protect coral reefs , mangrove and fishing resource
- Beyond the coral reef the open sea was dark blue
- a reef consisting of coral consolidated into limestone
Coral reefs are underwater structures made from calcium carbonate secreted by corals. Coral reefs are colonies of tiny living animals found in marine waters that contain few nutrients.