![Venice Lagoon December 9 2001](https://upload.wikimedia.org/wikipedia/commons/b/bf/Venice_Lagoon_December_9_2001.jpg)
A lagoon is a shallow
body of water
A body of water or waterbody (often spelled water body) is any significant accumulation of water on the surface of Earth or another planet. The term most often refers to oceans, seas, and lakes, but it includes smaller pools of water such a ...
separated from a larger body of water by a narrow
landform, such as
reef
A reef is a ridge or shoal of rock, coral or similar relatively stable material, lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic processes— deposition of sand, wave erosion planing down rock o ...
s,
barrier island
Barrier islands are coastal landforms and a type of dune system that are exceptionally flat or lumpy areas of sand that form by wave and tidal action parallel to the mainland coast. They usually occur in chains, consisting of anything from ...
s, barrier peninsulas, or
isthmus
An isthmus (; ; ) is a narrow piece of land connecting two larger areas across an expanse of water by which they are otherwise separated. A tombolo is an isthmus that consists of a spit or bar, and a strait is the sea counterpart of an isthmus ...
es. Lagoons are commonly divided into ''
coastal
The coast, also known as the coastline or seashore, is defined as the area where land meets the ocean, or as a line that forms the boundary between the land and the coastline. The Earth has around of coastline. Coasts are important zones in ...
lagoons'' (or ''barrier lagoons'') and ''
atoll
An atoll () is a ring-shaped island, including a coral rim that encircles a lagoon partially or completely. There may be coral islands or cays on the rim. Atolls are located in warm tropical or subtropical oceans and seas where corals can gr ...
lagoons''. They have also been identified as occurring on mixed-sand and gravel coastlines. There is an overlap between bodies of water classified as coastal lagoons and bodies of water classified as
estuaries
An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environmen ...
. Lagoons are common coastal features around many parts of the world.
Definition and terminology
Lagoons are shallow, often elongated bodies of water separated from a larger body of water by a shallow or exposed
shoal,
coral reef
A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in groups.
C ...
, or similar feature. Some authorities include
fresh water bodies in the definition of "lagoon", while others explicitly restrict "lagoon" to bodies of water with some degree of
salinity. The distinction between "lagoon" and "estuary" also varies between authorities. Richard A. Davis Jr. restricts "lagoon" to bodies of water with little or no fresh water inflow, and little or no
tidal
Tidal is the adjectival form of tide.
Tidal may also refer to:
* ''Tidal'' (album), a 1996 album by Fiona Apple
* Tidal (king), a king involved in the Battle of the Vale of Siddim
* TidalCycles, a live coding environment for music
* Tidal (servic ...
flow, and calls any
bay that receives a regular flow of fresh water an "estuary". Davis does state that the terms "lagoon" and "estuary" are "often loosely applied, even in scientific literature".
Timothy M. Kusky characterizes lagoons as normally being elongated parallel to the coast, while estuaries are usually drowned river valleys, elongated perpendicular to the coast.
Coastal lagoons are classified as inland bodies of water.
When used within the 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.
Many lagoons do not include "lagoon" in their common names. Currituck, Albemarle and Pamlico
The Pamlico (also ''Pampticough'', ''Pomouik'', ''Pomeiok'') were American Indians of North Carolina. They spoke an Algonquian language also known as ''Pamlico'' or ''Carolina Algonquian''.
Geography
The Pamlico Indians lived on the P ...
Sounds in North Carolina
North Carolina () is a state in the Southeastern region of the United States. The state is the 28th largest and 9th-most populous of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, Georgia and ...
, Great South Bay
The Great South Bay is a lagoon situated between Long Island and Fire Island, in the State of New York. It is about long and has an average depth of 4 feet 3 inches and is 20 feet at its deepest. It is protected from the Atlantic Ocean by Fire ...
between Long Island and the barrier beaches of Fire Island
Fire Island is the large center island of the outer barrier islands parallel to the South Shore of Long Island, in the U.S. state of New York.
Occasionally, the name is used to refer collectively to not only the central island, but also Lo ...
in New York, Isle of Wight Bay
Isle of Wight Bay is a lagoon that separates part of mainland Worcester County, Maryland from the midtown part of Ocean City, also in Worcester County. To the north, it connects to the Assawoman Bay just south of the Assawoman Bay Bridge, and to t ...
, which separates Ocean City, Maryland
Ocean City, officially the Town of Ocean City, is an Atlantic resort town in Worcester County, Maryland along the East Coast of the United States. The population was 6,844 at the 2020 U.S. census, although during summer weekends the city hosts b ...
from the rest of Worcester County, Maryland
Worcester County is the easternmost county of the U.S. state of Maryland. As of the 2020 census, the population was 52,460. Its county seat is Snow Hill.
It is the only county of Maryland that borders the Atlantic Ocean, and the only cou ...
, Banana River
The Banana River is a lagoon that lies between Cape Canaveral and Merritt Island in Brevard County, Florida in the United States. It is part of the Indian River Lagoon system, and connects at its south end to the Indian River; it is the only ...
in Florida
Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...
, US, Lake Illawarra
Lake Illawarra ( Aboriginal Tharawal language: various adaptions of ''Elouera'', ''Eloura'', or ''Allowrie''; ''Illa'', ''Wurra'', or ''Warra'' meaning pleasant place near the sea, or, high place near the sea, or, white clay mountain), is an ope ...
in New South Wales
)
, nickname =
, image_map = New South Wales in Australia.svg
, map_caption = Location of New South Wales in AustraliaCoordinates:
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, es ...
, Australia, Montrose Basin
Montrose Basin is a nearly circular tidal basin which makes up part of the estuary of the River South Esk and which sits just inland of the town of Montrose in Angus on the east coast of Scotland. The basin is protected by a number of designat ...
in Scotland
Scotland (, ) is a Countries of the United Kingdom, country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a Anglo-Scottish border, border with England to the southeast ...
, and Broad Water
Broad Water, or Broadwater (Welsh: ''Aber Dysynni'') is a salt water lagoon near Tywyn, Wales formed from the silted up estuary of the River Dysynni. In the eighteenth and nineteenth centuries, the estuary was used by the shipbuilding industry, ...
in Wales
Wales ( cy, Cymru ) is a country that is part of the United Kingdom. It is bordered by England to the east, the Irish Sea to the north and west, the Celtic Sea to the south west and the Bristol Channel to the south. It had a population in ...
have all been classified as lagoons, despite their names. In England, The Fleet at Chesil Beach has also been described as a lagoon.
In some languages the word for a lagoon is simply a type of lake: In Chinese a lake is ' (), and a lagoon is ' (). Contrariwise, several other languages have specific words for such bodies of water. In Spanish, coastal lagoons generically are ', but those on the Mediterranean coast are specifically called '. In Russian and Ukrainian, those on the Black Sea
The Black Sea is a marginal mediterranean sea of the Atlantic Ocean lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bounded by Bulgaria, Georgia, Rom ...
are ' (), while the generic word is ' (). Similarly, in the Baltic
Baltic may refer to:
Peoples and languages
* Baltic languages, a subfamily of Indo-European languages, including Lithuanian, Latvian and extinct Old Prussian
*Balts (or Baltic peoples), ethnic groups speaking the Baltic languages and/or originati ...
, Danish has the specific ', and German the specifics ' and , as well as generic terms derived from '. In New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
the Māori
Māori or Maori can refer to:
Relating to the Māori people
* Māori people of New Zealand, or members of that group
* Māori language, the language of the Māori people of New Zealand
* Māori culture
* Cook Islanders, the Māori people of the C ...
word ' refers to a coastal lagoon formed at the mouth of a braided river where there are mixed sand and gravel beaches, while , an ephemeral
Ephemerality (from the Greek word , meaning 'lasting only one day') is the concept of things being transitory, existing only briefly. Academically, the term ephemeral constitutionally describes a diverse assortment of things and experiences, fr ...
coastal waterbody, is neither a true lagoon, lake nor estuary.
Some languages differentiate between coastal and atoll lagoons. In French, ' refers specifically to an atoll lagoon, while coastal lagoons are described as , the generic word for a still lake or pond.
In Vietnamese, ' refers to an atoll lagoon, whilst ' is coastal.
In Latin America, the term ' in Spanish, which lagoon translates to, may be used for a small fresh water lake
A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...
in a similar way a creek is considered a small river. However, sometimes it is popularly used to describe a full-sized lake
A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...
, such as Laguna Catemaco in Mexico, which is actually the third-largest lake by area in the country. The brackish water
Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuari ...
lagoon may be thus explicitly identified as a "coastal lagoon" ('). In Portuguese, a similar usage is found: ' may be a body of shallow seawater, or a small freshwater lake not linked to the sea.
Etymology
Lagoon is derived from the Italian
Italian(s) may refer to:
* Anything of, from, or related to the people of Italy over the centuries
** Italians, an ethnic group or simply a citizen of the Italian Republic or Italian Kingdom
** Italian language, a Romance language
*** Regional Ita ...
', which refers to the waters around Venice
Venice ( ; it, Venezia ; vec, Venesia or ) is a city in northeastern Italy and the capital of the Veneto region. It is built on a group of 118 small islands that are separated by canals and linked by over 400 bridges. The isla ...
, the Venetian Lagoon. ''Laguna'' is attested in English by at least 1612, and had been Anglicized
Anglicisation is the process by which a place or person becomes influenced by English culture or British culture, or a process of cultural and/or linguistic change in which something non-English becomes English. It can also refer to the influenc ...
to "lagune" by 1673. In 1697 William Dampier
William Dampier (baptised 5 September 1651; died March 1715) was an English explorer, pirate, privateer, navigator, and naturalist who became the first Englishman to explore parts of what is today Australia, and the first person to circumnav ...
referred to a "Lagune or Lake of Salt water" on the coast of Mexico. Captain James Cook
James Cook (7 November 1728 Old Style date: 27 October – 14 February 1779) was a British explorer, navigator, cartographer, and captain in the British Royal Navy, famous for his three voyages between 1768 and 1779 in the Pacific Ocean and ...
described an island "of Oval form with a Lagoon in the middle" in 1769.
Atoll lagoons
Atoll
An atoll () is a ring-shaped island, including a coral rim that encircles a lagoon partially or completely. There may be coral islands or cays on the rim. Atolls are located in warm tropical or subtropical oceans and seas where corals can gr ...
lagoons form as coral reefs grow upwards while the islands that the reefs surround subside, until eventually only the reefs remain above sea level. Unlike the lagoons that form shoreward of fringing reefs, atoll lagoons often contain some deep (>) portions.
Coastal lagoons
Coastal lagoons form along gently sloping coasts where barrier islands or reefs can develop offshore, and the sea-level is rising relative to the land along the shore (either because of an intrinsic rise in sea-level, or subsidence of the land along the coast). Coastal lagoons do not form along steep or rocky coasts, or if the range of tides is more than . Due to the gentle slope of the coast, coastal lagoons are shallow. A relative drop in sea level may leave a lagoon largely dry, while a rise in sea level may let the sea breach or destroy barrier islands, and leave reefs too deep underwater to protect the lagoon. Coastal lagoons are young and dynamic, and may be short-lived in geological terms. Coastal lagoons are common, occurring along nearly 15 percent of the world's shorelines. In the United States, lagoons are found along more than 75 percent of the Eastern
Eastern may refer to:
Transportation
*China Eastern Airlines, a current Chinese airline based in Shanghai
*Eastern Air, former name of Zambia Skyways
*Eastern Air Lines, a defunct American airline that operated from 1926 to 1991
*Eastern Air Li ...
and Gulf Coasts.[
Coastal lagoons are usually connected to the open ocean by inlets between barrier islands. The number and size of the inlets, precipitation, evaporation, and inflow of fresh water all affect the nature of the lagoon. Lagoons with little or no interchange with the open ocean, little or no inflow of fresh water, and high evaporation rates, such as Lake St. Lucia, in ]South Africa
South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. It is bounded to the south by of coastline that stretch along the Atlantic Ocean, South Atlantic and Indian Oceans; to the ...
, may become highly saline. Lagoons with no connection to the open ocean and significant inflow of fresh water, such as the Lake Worth Lagoon
The Lake Worth Lagoon is a lagoon located in Palm Beach County, Florida. It runs parallel to the coast, and is separated from the Atlantic Ocean by barrier beaches, including Palm Beach Island. The lagoon is connected to the Atlantic Ocean by two ...
in Florida in the middle of the 19th century, may be entirely fresh. On the other hand, lagoons with many wide inlets, such as the Wadden Sea, have strong tidal currents and mixing. Coastal lagoons tend to accumulate sediments from inflowing rivers, from runoff from the shores of the lagoon, and from sediment carried into the lagoon through inlets by the tide. Large quantities of sediment may be occasionally be deposited in a lagoon when storm waves overwash barrier islands. Mangrove
A mangrove is a shrub or tree that grows in coastal saline or brackish water. The term is also used for tropical coastal vegetation consisting of such species. Mangroves are taxonomically diverse, as a result of convergent evolution in severa ...
s and marsh
A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found a ...
plants can facilitate the accumulation of sediment in a lagoon. Benthic organisms may stabilize or destabilize sediments.[
]
Largest coastal lagoons
* New Caledonian lagoon:
*:
*Mayotte lagoon
Mayotte (; french: Mayotte, ; Shimaore: ''Maore'', ; Kibushi: ''Maori'', ), officially the Department of Mayotte (french: Département de Mayotte), is an overseas department and region and single territorial collectivity of France. It is locat ...
: ~
* Rangiroa lagoon:
*Marovo Lagoon
Marovo Lagoon is the largest saltwater lagoons in the world. Located in the New Georgia Islands, surrounded by Vangunu Island and Nggatokae Island, both extinct volcanic islands, at . It is part of the Solomon Islands. It encompasses and is prote ...
:
Regulation
In the European Union
The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been de ...
, coastal lagoon habitat is classified and under Directive 92/43/EEC on the conservation of natural habitats and wild flora and fauna (Habitats Directive
The Habitats Directive (more formally known as Council Directive 92/43/EEC on the Conservation of natural habitats and of wild fauna and flora) is a directive adopted by the European Community in 1992 as a response to the Berne Convention. The E ...
). Furthermore, numerous bird species breed in coastal lagoons. As a result, many lagoons are also protected under Directive 2009/147/EC on the conservation of birds (Birds Directive
The Birds Directive (formally known as Council Directive 2009/147/EC on the conservation of wild birds) is the oldest piece of EU legislation on the environment and one of its cornerstones which was unanimously adopted in April 1979 as the Dire ...
).
Images
See also
* Aerated lagoon
An aerated lagoon (or aerated pond) is a simple wastewater treatment system consisting of a pond with artificial aeration to promote the biological oxidation of wastewaters.
There are many other aerobic biological processes for treatment of waste ...
* Anaerobic lagoon An anaerobic lagoon or manure lagoon is a man-made outdoor earthen basin filled with animal waste that undergoes anaerobic respiration as part of a system designed to manage and treat refuse created by concentrated animal feeding operations (CAFOs). ...
* Ayre (landform)
An ayre is the name used for shingle beaches found in Orkney, Shetland, the Isle of Man, Lancashire, Cumbria and Northumbria. The word is derived from the Old Norse ''eyrr'', meaning a shingle beach or gravelly place, and may be applied to ordina ...
* Braided river
* Coast
The coast, also known as the coastline or seashore, is defined as the area where land meets the ocean, or as a line that forms the boundary between the land and the coastline. The Earth has around of coastline. Coasts are important zones in ...
* Estuary
An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environm ...
* Longshore drift
* Sediment transport
External links
Coastal lagoon
References
{{Authority control
Coastal and oceanic landforms
Oceanographical terminology
Bodies of water