Glossary:Lagoon

lagoon

Lagoons are separated from larger bodies of water by sandbars, barrier reefs, coral reefs, or other natural barriers. The word "lagoon" derives from the Italian word laguna, which means "pond" or "lake."

• A shallow stretch of salt or brackish water, partly or completely separated from a sea or lake by an offshore reef, barrier island, sandbank or spit

Word Class: noun

Pronunciation: la·goon / ləˈɡo͞on

Synonym: estuary

Example: A lagoon is a body of water separated from larger bodies of water by a natural barrier.

What is a lagoon?

Indian River Lagoon

There are two types of lagoons: atoll and coastal. Atoll lagoons form when an island completely subsides beneath the water, leaving a ring of coral that continues to grow upwards. At the center of the ring is a body of water that is often deep. The combination of coral growth and water creates a lagoon. It may take as long as 300,000 years for an atoll formation to occur.

Coastal lagoons form along gently sloping coasts. They are generally shallower than atoll lagoons and tend to be separated from the ocean by an island, reef, or sand bank. Most of the time, coastal lagoons are connected to the ocean by an inlet.

Sea level rise, the amount of existing sediment, and tidal range all contribute to the formation of coastal lagoons. Younger and more dynamic than atoll lagoons, coastal lagoons may have shorter “lifespans” due to their exposed locations on the shore.