lagoon

A lagoon is a body of shallow sea water or brackish water separated from the sea by some form of barrier. The EU's habitat directive defines lagoons as "expanses of shallow coastal salt water, of varying salinity or water volume, wholly or partially separated from the sea by sand banks or shingle, or, less frequently, by rocks. Salinity may vary from brackish water to hypersalinity depending on rainfall, evaporation and through the addition of fresh seawater from storms, temporary flooding by the sea in winter or tidal exchange".

Definition

Garabogaz-Göl lagoon in Turkmenistan.

The body of comparatively shallow salt or brackish water is separated from the deeper sea by a shallow or exposed barrier beach, sandbank of marine origin, coral reef, or similar feature.^[1] Thus, the enclosed body of water behind a barrier reef or barrier islands or enclosed by an atoll reef is called a lagoon. When used within this context of a distinctive portion of coral reef ecosystems, the term "lagoon" is synonymous with the term "back reef" or "backreef", which is more commonly used by coral reef scientists to refer to the same area.^[2]

These applications of lagoon in English date from 1769. It adapted and extended the sense of the Venetian laguna (cf Latin lacuna, ‘empty space’), which specifically referred to Venice’s shallow, island-studded stretch of saltwater, protected from the Adriatic by the barrier beaches of the Lido. Lagoon refers to both coastal lagoons formed by the build-up of sandbanks or reefs along shallow coastal waters, and the lagoons in atolls formed by the growth of coral reefs on slowly sinking central islands. Lagoons that are fed by freshwater streams are also called estuaries.

Many lagoons do not include "lagoon" in their common names. Albemarle Sound in North Carolina; Great South Bay between Long Island and the barrier beaches of Fire Island in New York; Isle of Wight Bay, which separates Ocean City, Maryland from the rest of Worcester County, Maryland; Banana River in Florida; and Lake Illawarra in New South Wales are all lagoons, despite their names. In the UK there are lagoons at Montrose Basin, (Scotland) and Broad Water near Tywyn, (Wales), whilst the expanse of water inside Chesil Beach, England, known as The Fleet, could also be described as a lagoon. There is also one near the small town of Dingle in Western Ireland. Some of the lagoons in India are the Chilika Lake in Orissa, near Puri, and the Vembanad Lake in Kerala. Both are connected to the Bay of Bengal and the Arabian Sea respectively through a narrow channel. Some other known lagoons like in Africa include the Lagos Lagoon and the Keta Lagoon in Ghana.

In Latin America often the use of “laguna”, which lagoon translates to, is used to describe a lake, such as Laguna Catemaco.

In pop culture, the movie Creature from the Black Lagoon (1954) is a popular monster movie.

Images

• 

  Glenrock Lagoon in Australia

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  Lagoa dos Patos lagoon in Brazil

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  Venetian Lagoon as seen by Landsat 1

• 

  Szczecin Lagoon as seen by Landsat c. 2000.

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  Vistula and Curonian lagoons on the Baltic Sea.

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  Nearly half the area of Kiritimati is covered with lagoons, some freshwater and some seawater.

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  Blue lagoon, Ölüdeniz, Turkey

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  Washdyke Lagoon in New Zealand

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  Marano Lagoon in Lignano Sabbiadoro, Italy

See also

• Aerated lagoon
• Anaerobic lagoon
• Ayre (landform)
• Kerala backwaters
• Estuary

Notes

References

Wikimedia Commons has media related to: Lagoons

• Reid, George K. (1961). Ecology of Inland Waters and Estuaries. New York: Van Nostrand Reinhold Company. 
• Aronson, R.B. (1993). "Hurricane effects on backreef echinoderms of the Caribbean". Coral Reefs. 

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