Reef

Underwater structure formed from coral, rock, or other organic materials.

coral reef Riff

A reef is a ridge or underwater structure formed from the accumulation of coral, rock, or other organic materials. Reefs often serve as habitats for marine life and can be found in coastal waters or along the ocean floor.

From Old English rēaf meaning 'plunder, spoil,' related to the idea of a submerged obstacle.

A reef is like an underwater city built by tiny animals called coral, or sometimes made of rocks and other things!

What is a reef? An underwater structure formed from coral, rock, or other organic materials
Where are reefs found? Typically in shallow waters, often in tropical climates
Why are reefs important? They provide habitats for many marine species and protect coastlines

coral reef barrier reef

geological formation underwater structure

fringing reef barrier reef atoll

coral rock sand

ocean sea

marine ecosystem natural object