Lagoon

Alagoonis a shallowbody of waterseparated from a larger body of water by a narrowlandform,such asreefs,barrier islands,barrier peninsulas, oristhmuses.Lagoons are commonly divided intocoastallagoons(orbarrier lagoons) andatolllagoons.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 asestuaries.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 exposedshoal,coral reef,or similar feature. Some authorities includefresh waterbodies in the definition of "lagoon", while others explicitly restrict "lagoon" to bodies of water with some degree ofsalinity.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 notidalflow, and calls anybaythat 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".^[1]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.^[1]^[2]^[3]^[4]^[5]Coastal lagoons are classified as inland bodies of water.^[6]^[7]

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.^[8]

Many lagoons do not include "lagoon" in their common names.Currituck,AlbemarleandPamlicoSounds inNorth Carolina,^[9]Great South BaybetweenLong Islandand the barrier beaches ofFire IslandinNew York,^[10]Isle of Wight Bay,which separatesOcean City, Marylandfrom the rest ofWorcester County, Maryland,^[11]Banana RiverinFlorida,US,^[12]Lake IllawarrainNew South Wales,Australia,^[13]Montrose BasininScotland,^[14]andBroad WaterinWaleshave all been classified as lagoons, despite their names. In England,The Fleetat 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 ishu(Hồ), and a lagoon isxihu(Tả hồ). In theFrenchMediterranean several lagoons are calledétang( "lake" ). Contrariwise, several other languages have specific words for such bodies of water. In Spanish, coastal lagoons generically arelaguna costera,but those on the Mediterranean coast are specifically calledalbufera.In Russian and Ukrainian, those on theBlack Seaareliman(лиман), while the generic word islaguna(Лагуна). Similarly, in theBaltic,Danish has the specificNor[da],and German the specificsBoddenandHaff,as well as generic terms derived fromlaguna.In Poland these lagoons are calledzalew( "bay" ), in Lithuaniamarios( "lagoon, reservoir" ). InJutlandseveral lagoons are known asfjord.InNew ZealandtheMāoriwordhapuarefers to a coastal lagoon formed at the mouth of abraided riverwhere there are mixed sand and gravel beaches, whilewaituna,anephemeralcoastal waterbody, is neither a true lagoon, lake nor estuary.^[15]

Some languages differentiate between coastal and atoll lagoons. In French,lagon[fr]refers specifically to an atoll lagoon, while coastal lagoons are described asétang[fr],the generic word for a still lake or pond. In Vietnamese,Đầm san hôrefers to an atoll lagoon, whilstĐầm pháis coastal.

In Latin America, the termlagunain Spanish, which lagoon translates to, may be used for a small fresh waterlakein a similar way acreekis considered a small river. However, sometimes it is popularly used to describe a full-sizedlake,such asLaguna Catemacoin Mexico, which is actually the third-largest lake by area in the country. Thebrackish waterlagoon may be thus explicitly identified as a "coastal lagoon" (laguna costera). In Portuguese, a similar usage is found:lagoamay be a body of shallow seawater, or a small freshwater lake not linked to the sea.

Etymology

Lagoon is derived from theItalianlaguna,which refers to the waters aroundVenice,theVenetian Lagoon.Lagunais attested in English by at least 1612, and had beenAnglicizedto "lagune" by 1673. In 1697William Dampierreferred to a "Lagune or Lake of Salt water" on the coast of Mexico.Captain James Cookdescribed an island "of Oval form with a Lagoon in the middle" in 1769.^[16]

Atoll lagoons

Satellite picture of theAtafuatoll inTokelauin thePacific Ocean

Atolllagoons 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 (>20 m (66 ft)) 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, orsubsidenceof the land along the coast). Coastal lagoons do not form along steep or rocky coasts, or if the range of tides is more than 4 metres (13 ft). 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 theEasternandGulf Coasts.^[3]^[4]

Coastal lagoons can be classified as leaky, restricted, or choked.^[17] Coastal lagoons are usually connected to the open ocean byinletsbetween 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 asLake St. Lucia,inSouth Africa,may become highly saline. Lagoons with no connection to the open ocean and significant inflow of fresh water, such as theLake Worth Lagoonin Florida in the middle of the 19th century, may be entirely fresh. On the other hand, lagoons with many wide inlets, such as theWadden 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.Mangrovesandmarshplants can facilitate the accumulation of sediment in a lagoon.Benthic organismsmay stabilize or destabilize sediments.^[3]^[4]

Largest coastal lagoons

Lagoon	Area	Country
New Caledonian lagoon	24,000 km²(9,300 sq mi)	New Caledonia
Garabogazköl	18,000 km²(6,900 sq mi)	Turkmenistan
Lake Maracaibo	13,512 km²(5,217 sq mi)	Venezuela
Lagoa dos Patos^[a]	10,100 km²(4,000 sq mi)	Brazil
Albemarle-Pamlicosound system	7,800 km²(3,000 sq mi)	United States
Lagos Lagoon	6,354.7 km²(2,453.6 sq mi)	Nigeria
Curonian lagoon	1,619 km²(625 sq mi)	Lithuania/Russia
Mayotte lagoon	~1,500 km²(600 sq mi)	France
Rangiroa lagoon	1,446 km²(600 sq mi)	French Polynesia
Chilika Lake	1,165 km²(450 sq mi) during monsoon season, 906 km²(350 sq mi) during dry season	India
Indian River Lagoon	910 km²(353 sq mi)^[18]	United States
Vistula lagoon	838 km²(324 sq mi)	Russia/Poland
Biscayne BaySystem —Biscayne Bay (traditional)	703 km²(271 sq mi)^[19] 572 km²(221 sq mi)^[20]	United States
Marovo lagoon	700 km²(270 sq mi)	Solomon Islands
Szczecin Lagoon	689 km²(266 sq mi)	Germany/Poland
Venetian lagoon	550 km²(210 sq mi)	Italy

Images

Lagoa dos Patos,the largest lagoon in South America, in theBrazilian stateofRio Grande do Sul.
Aerial view ofBora BorainFrench Polynesia.
Aerial view ofKivalina, Alaskafrom the northwest.
Nearly half the area ofKiritimatiis covered with lagoons, some freshwater and some seawater.
Nusa Lembongan Lagoon,Bali,Indonesia.
Panoramic view of Lefkada City Lagoon, Lefkada Isl.,Ionian IslandsPrefecture,Greece.
Panoramic view of Prokopos Lagoon,Achaia,Western Greece Prefecture, Greece.
Tropical lagoon in Bacuit Bay, Palawan, Philippines.
Photo ofMar Menoras seen from International Space Station.

Notes

^The largest choked coastal lagoon.^[17]

References

^^a ^bDavis, Richard A. Jr. (1994).The Evolving Coast.New York: Scientific American Library. pp.101, 107.ISBN 978-0-7167-5042-0.
^Allaby, Michael, ed. (1990). "Lagoon".Oxford Dictionary of Earth Sciences.Oxford: Oxford University Press.ISBN 978-0-19-921194-4.
^^a ^b ^cKusky, Timothy, ed. (2005)."Lagoon".Encyclopedia of Earth Sciences.New York: Facts on File. p.245.ISBN 0-8160-4973-4.
^^a ^b ^cNybakken, James W., ed. (2003). "Lagoon".Interdisciplinary Encyclopedia of Marine Sciences.Vol. 2 G-O. Danbury, Connecticut: Grolier Academic Reference. pp. 189–90.ISBN 0-7172-5946-3.
^Reid, George K. (1961).Ecology of Inland Waters and Estuaries.New York: Van Nostrand Reinhold Company. p.74.ASIN B003MRW6AK.
^Maurice L. Schwartz (2005).Encyclopedia of coastal science.Springer. p. 263.ISBN 978-1-4020-1903-6.Retrieved31 March2012.
^Kjerfve, Björn (1994). "Coastal Lagoons".Coastal lagoon processes.Elsevier. pp. 1–3.ISBN 978-0-444-88258-5.
^Aronson, R. B. (1993). "Hurricane effects on backreef echinoderms of the Caribbean".Coral Reefs.12(3–4): 139–142.Bibcode:1993CorRe..12..139A.doi:10.1007/BF00334473.S2CID 879073.
^Jia, Peng and Ming Li (2012)."Circulation dynamics and salt balance in a lagoonal estuary".Journal of Geophysical Research: Oceans.117(C01003): C01003.Bibcode:2012JGRC..117.1003J.doi:10.1029/2011JC007124.Archived fromthe originalon Aug 19, 2014.Retrieved24 March2012.
^Goodbred, S. Jr., P. Locicero, V. Bonvento, S. Kolbe, S. Holsinger."History of the Great South Bay estuary:Evidence of a catastrophic origin".State University of New York.Retrieved24 March2012.{{cite web}}:CS1 maint: multiple names: authors list (link)
^Boynton, W. R., J. D. Hagy, L. Murray, C. Stokes, W. M Kemp (June 1996)."A Comparative Analysis of Eutrophication Patterns in a Temperate Coastal Lagoon"(PDF).Estuaries.19(2B): 408–421.doi:10.2307/1352459.JSTOR 1352459.S2CID 14978943.Retrieved24 March2012.{{cite journal}}:CS1 maint: multiple names: authors list (link)
^"Total Maximum Daily Loads for the North and Central Indian River Lagoon and Banana river Lagoon, Florida"(PDF).United States Environmental Protection Agency. Archived fromthe original(PDF)on 24 September 2015.Retrieved24 March2012.
^"Proposed Swimming Enclosure Net, Entrance Lagoon, Lake Illawarra"(PDF).Lake Illawarra Authority. Archived fromthe original(PDF)on 28 February 2011.Retrieved24 March2012.
^Bird, Eric C. F. (2010).Encyclopedia of the World's Coastal Landforms.Vol. 1. Dordrecht: Springer. p. 485.ISBN 978-1-4020-8638-0.
^Kirk, R.M. and Lauder, G.A (2000).Significant coastal lagoon systems in the South Island, New Zealand: coastal processes and lagoon mouth closure.Wellington, N.Z.:Department of Conservation.ISBN 0-478-21947-4.{{cite book}}:CS1 maint: multiple names: authors list (link)
^"Lagoon".Oxford English Dictionary.Vol. I A-O (Compact ed.). Oxford, England: Oxford University Press. 1971. p. 1560.
^^a ^bKjerfve, Björn(1986). "Comparative oceanography of coastal lagoons".Estuarine Variability.Elsevier. pp. 63–81.doi:10.1016/b978-0-12-761890-6.50009-5.ISBN 978-0-12-761890-6.
^"Fast facts about the Indian River Lagoon".St. Johns River Water Management District.2024.Retrieved12 July2024.
^Smith, Ned P. (Summer 2001). "Tides of Biscayne Bay, Card Sound, Little Card Sound, Barnes Sound, and Manatee Bay, Florida".Florida Scientist.64:224.JSTOR 24321024.
^Milano, Gary R. (2000). "Introduction".Island Restoration and Enhancement in Biscayne Bay, Florida(PDF).Miami-Dade Department of Environmental Resources Management(Report).RetrievedApril 21,2021.

[18] The largest choked coastal lagoon.^[17]

[Davis-1] Davis, Richard A. Jr. (1994).The Evolving Coast.New York: Scientific American Library. pp.101, 107.ISBN 978-0-7167-5042-0.

[2] Allaby, Michael, ed. (1990). "Lagoon".Oxford Dictionary of Earth Sciences.Oxford: Oxford University Press.ISBN 978-0-19-921194-4.

[Kusky-3] Kusky, Timothy, ed. (2005)."Lagoon".Encyclopedia of Earth Sciences.New York: Facts on File. p.245.ISBN 0-8160-4973-4.

[Nybakken-4] Nybakken, James W., ed. (2003). "Lagoon".Interdisciplinary Encyclopedia of Marine Sciences.Vol. 2 G-O. Danbury, Connecticut: Grolier Academic Reference. pp. 189–90.ISBN 0-7172-5946-3.

[5] Reid, George K. (1961).Ecology of Inland Waters and Estuaries.New York: Van Nostrand Reinhold Company. p.74.ASIN B003MRW6AK.

[6] Maurice L. Schwartz (2005).Encyclopedia of coastal science.Springer. p. 263.ISBN 978-1-4020-1903-6.Retrieved31 March2012.

[7] Kjerfve, Björn (1994). "Coastal Lagoons".Coastal lagoon processes.Elsevier. pp. 1–3.ISBN 978-0-444-88258-5.

[8] Aronson, R. B. (1993). "Hurricane effects on backreef echinoderms of the Caribbean".Coral Reefs.12(3–4): 139–142.Bibcode:1993CorRe..12..139A.doi:10.1007/BF00334473.S2CID 879073.

[9] Jia, Peng and Ming Li (2012)."Circulation dynamics and salt balance in a lagoonal estuary".Journal of Geophysical Research: Oceans.117(C01003): C01003.Bibcode:2012JGRC..117.1003J.doi:10.1029/2011JC007124.Archived fromthe originalon Aug 19, 2014.Retrieved24 March2012.

[10] Goodbred, S. Jr., P. Locicero, V. Bonvento, S. Kolbe, S. Holsinger."History of the Great South Bay estuary:Evidence of a catastrophic origin".State University of New York.Retrieved24 March2012.{{cite web}}:CS1 maint: multiple names: authors list (link)

[11] Boynton, W. R., J. D. Hagy, L. Murray, C. Stokes, W. M Kemp (June 1996)."A Comparative Analysis of Eutrophication Patterns in a Temperate Coastal Lagoon"(PDF).Estuaries.19(2B): 408–421.doi:10.2307/1352459.JSTOR 1352459.S2CID 14978943.Retrieved24 March2012.{{cite journal}}:CS1 maint: multiple names: authors list (link)

[12] "Total Maximum Daily Loads for the North and Central Indian River Lagoon and Banana river Lagoon, Florida"(PDF).United States Environmental Protection Agency. Archived fromthe original(PDF)on 24 September 2015.Retrieved24 March2012.

[13] "Proposed Swimming Enclosure Net, Entrance Lagoon, Lake Illawarra"(PDF).Lake Illawarra Authority. Archived fromthe original(PDF)on 28 February 2011.Retrieved24 March2012.

[14] Bird, Eric C. F. (2010).Encyclopedia of the World's Coastal Landforms.Vol. 1. Dordrecht: Springer. p. 485.ISBN 978-1-4020-8638-0.

[15] Kirk, R.M. and Lauder, G.A (2000).Significant coastal lagoon systems in the South Island, New Zealand: coastal processes and lagoon mouth closure.Wellington, N.Z.:Department of Conservation.ISBN 0-478-21947-4.{{cite book}}:CS1 maint: multiple names: authors list (link)

[16] "Lagoon".Oxford English Dictionary.Vol. I A-O (Compact ed.). Oxford, England: Oxford University Press. 1971. p. 1560.

[Kjerfve1986-17] Kjerfve, Björn(1986). "Comparative oceanography of coastal lagoons".Estuarine Variability.Elsevier. pp. 63–81.doi:10.1016/b978-0-12-761890-6.50009-5.ISBN 978-0-12-761890-6.

[19] "Fast facts about the Indian River Lagoon".St. Johns River Water Management District.2024.Retrieved12 July2024.

[20] Smith, Ned P. (Summer 2001). "Tides of Biscayne Bay, Card Sound, Little Card Sound, Barnes Sound, and Manatee Bay, Florida".Florida Scientist.64:224.JSTOR 24321024.

[21] Milano, Gary R. (2000). "Introduction".Island Restoration and Enhancement in Biscayne Bay, Florida(PDF).Miami-Dade Department of Environmental Resources Management(Report).RetrievedApril 21,2021.

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

[10]

[11]

[12]

[13]

[14]

[15]

[16]

[17]

[a]

[18]

[19]

[20]

v t e Coastal geography
Landforms	Anchialine pool Archipelago Atoll Avulsion Ayre Barrier island Bay Bight Bodden Brackish marsh Cape Channel Cliff Coast Coastal plain Coastal waterfall Continental margin Continental shelf Coral reef Cove Dune cliff-top Estuary Firth Fjard Fjord Freshwater marsh Fundus Gat Geo Gulf Gut Hapua Headland Inlet Intertidal wetland Island Islet Isthmus Lagoon Machair Mudflat Natural arch Peninsula Reef Ria Salt marsh Shoal Skerry Sound Spit Stack Strait Strand plain Submarine canyon Tidal island Tidal marsh Tide pool Tied island Tombolo Waituna Windwatt
Beaches	Beach cusps Beach evolution Beach ridge Beach wrack Beaches in estuaries and bays Beachrock Coastal morphodynamics Pocket beach Raised beach Recession Shell beach Shingle beach Storm beach Wash margin
River mouths	Debouch Mouth bar River delta mega regressive
Processes	Blowhole Cliffed coast Coastal biogeomorphology Coastal erosion Concordant coastline Current Cuspate foreland Discordant coastline Emergent coastline Feeder bluff Flat coast Graded shoreline Ingression coast Large-scale coastal behaviour Longshore drift Marine regression Marine transgression Raised shoreline Rip current Rocky shore Sea cave Sea foam Shoal peresyp Steep coast Submergent coastline Surf break Surf zone Surge channel Swash Undertow Volcanic arc Wave-cut platform Wave shoaling Wind fetch Wind wave
Management	Accretion Coastal management Integrated coastal zone management Submersion
Related	Bulkhead line Coastal engineering Grain size boulder clay cobble granule gravel pebble sand shingle silt Intertidal zone Littoral zone Physical oceanography Region of freshwater influence River plume
Category

Authority control databases
International	FAST
National	United States France BnF data Japan Israel