Most coral reefs are in danger , according to estimates from the Nature Conservancy . The organization says 500 million people depend on coral reefs for food . According to the Nature Conservancy , if the present rate of destruction continues , 70 percent of the world 's coral reefs will be destroyed by the year 2050 . Reef ##s are concrete objects upon which a natural reef can grow . The objects also help control coastal erosion and stabilize shorelines .
Most coral reefs are in danger , according to estimates from the Nature Conservancy . The organization says 500 million people depend on coral reefs for food . Reef ##s are concrete objects upon which a natural reef can grow . The objects also help control coastal erosion and stabilize shorelines .