text: Such corals require sunlight and grow in clear , shallow water , typically at depths shallower than 60 m. Corals can be major contributors to the physical structure of the coral reefs that develop in tropical and subtropical waters , such as the enormous Great Barrier Reef off the coast of Queensland , Australia .
simplified: Such corals need sunlight and grow in clear , shallow water , typically at depths less than 60 metres ( 200 ft ) .