Identify the Circular Coral Reef Type

The question asks for the specific type of circular coral reef that encloses a lagoon.

An Atoll is defined as a ring-shaped coral reef, island, or series of islets that surrounds a lagoon. This fits the description perfectly.

Understanding Coral Reef Classifications

• Atoll: A circular or nearly circular reef structure that encloses a central lagoon. This is formed typically around a subsided volcanic island.
• Barrier Reef: A reef separated from the mainland or island shore by a deep channel or lagoon. They often run parallel to the coast but are not necessarily circular.
• Fringing Reef: A reef that grows directly from the shore or is separated by a very narrow, shallow channel. They lack a significant enclosed lagoon.

Based on these definitions, the circular coral reef that encloses a lagoon is an Atoll.