Reefs that are separated by a lagoon from the land mass they surround are called:

Question

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Barrier reefs are separated from a mainland or island shore by a deep lagoon, distinguishing them from other types of reefs such as atolls, which are circular coral reef islands that encircle a lagoon, and fringing reefs, which are directly attached to the shore of an island or continent without an intervening lagoon. Patch reefs are small, isolated reefs that usually occur within a lagoon or between larger reefs, and table reefs are not a commonly classified type of coral reef.

Reefs That Are Separated by a Lagoon from the Land