![MaraisSalant](https://upload.wikimedia.org/wikipedia/commons/b/bb/MaraisSalant.JPG)
A salt evaporation pond is a shallow artificial
salt pan designed to extract
salt
Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quantitie ...
s from
sea water
Seawater, or salt water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has approx ...
or other
brine
Brine is a high-concentration solution of salt (NaCl) in water (H2O). In diverse contexts, ''brine'' may refer to the salt solutions ranging from about 3.5% (a typical concentration of seawater, on the lower end of that of solutions used for br ...
s. The Salt pans are shallow and large of size because it will be easier for sunlight to travel and reach the sea water. Natural salt pans are geological formations that are also created by water evaporating and leaving behind salts. Some salt evaporation ponds are only slightly modified from their natural version, such as the ponds on
Great Inagua
Inagua is the southernmost district of the Bahamas, comprising the islands of Great Inagua and Little Inagua. The headquarters for the district council are in Matthew Town.
History
The original settlers were the Lucayan people, who arrived some ...
in
the Bahamas
The Bahamas (), officially the Commonwealth of The Bahamas, is an island country within the Lucayan Archipelago of the West Indies in the Atlantic Ocean, North Atlantic. It takes up 97% of the Lucayan Archipelago's land area and is home to ...
, or the ponds in Jasiira, a few kilometres south of
Mogadishu
Mogadishu (, also ; so, Muqdisho or ; ar, مقديشو ; it, Mogadiscio ), locally known as Xamar or Hamar, is the capital and List of cities in Somalia by population, most populous city of Somalia. The city has served as an important port ...
, where seawater is trapped and left to evaporate in the sun.
The seawater or brine is fed into large ponds and water is drawn out through natural
evaporation
Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. High concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when humidi ...
which allows the salt to be subsequently harvested.
The ponds also provide a productive resting and feeding ground for many species of
waterbird
A water bird, alternatively waterbird or aquatic bird, is a bird that lives on or around water. In some definitions, the term ''water bird'' is especially applied to birds in freshwater ecosystems, although others make no distinction from seabi ...
s, which may include
endangered
An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inva ...
species. The ponds are commonly separated by
levees
A levee (), dike (American English), dyke (Commonwealth English), embankment, floodbank, or stop bank is a structure that is usually earthen and that often runs parallel to the course of a river in its floodplain or along low-lying coastli ...
. Salt evaporation ponds may also be called salterns, salt works or salt pans.
Algae and color
![Salt ponds SF Bay (dro!d)](https://upload.wikimedia.org/wikipedia/commons/2/22/Salt_ponds_SF_Bay_%28dro%21d%29.jpg)
Due to variable
algal
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...
concentrations, vivid colors (from pale green to bright red) are created in the evaporation ponds. The color indicates the salinity of the ponds.
Microorganism
A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in olde ...
s change their hues as the
salinity
Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal ...
of the pond increases. In low- to mid-salinity ponds, green algae such as ''
Dunaliella salina
''Dunaliella salina'' is a type of halophile green unicellular micro-algae especially found in hypersaline environments, such as salt lakes and salt evaporation ponds. Known for its antioxidant activity because of its ability to create large ...
'' are predominant, although these algae can also take on an orange hue. In middle- to high-salinity ponds,
Halobacteria
Haloarchaea (halophilic archaea, halophilic archaebacteria, halobacteria) are a class of the Euryarchaeota, found in water saturated or nearly saturated with salt. Halobacteria are now recognized as archaea rather than bacteria and are one of th ...
, which is actually a group of halophilic
Archaea
Archaea ( ; singular archaeon ) is a domain of single-celled organisms. These microorganisms lack cell nuclei and are therefore prokaryotes. Archaea were initially classified as bacteria, receiving the name archaebacteria (in the Archaebac ...
(sometimes called
Haloarchaea
Haloarchaea (halophilic archaea, halophilic archaebacteria, halobacteria) are a class of the Euryarchaeota, found in water saturated or nearly saturated with salt. Halobacteria are now recognized as archaea rather than bacteria and are one of t ...
), shift the colour to pink, red and orange. Other
bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...
such as ''
Stichococcus
''Stichococcus'' is a genus of green algae in the family Prasiolaceae
Prasiolaceae is a family of green algae in the order Prasiolales.See the NCBI
The National Center for Biotechnology Information (NCBI) is part of the United States Nat ...
'' also contribute
tint
In color theory, a tint is a mixture of a color with white, which increases lightness, while a shade is a mixture with black, which increases darkness. Both processes affect the resulting color mixture's relative saturation. A tone is produc ...
s.
Examples
Notable salt ponds include:
* The
Salterns of Guérande, in
Loire-Atlantique
Loire-Atlantique (; br, Liger-Atlantel; before 1957: ''Loire-Inférieure'', br, Liger-Izelañ, link=no) is a department in Pays de la Loire on the west coast of France, named after the river Loire and the Atlantic Ocean. It had a population o ...
,
France
France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...
. The salt produced in the salterns are a
protected geographical indication
Three European Union schemes of geographical indications and traditional specialties, known as protected designation of origin (PDO), protected geographical indication (PGI), and traditional specialities guaranteed (TSG), promote and protect nam ...
in
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...
.
* The
Cáhuil
Cáhuil ( arn, Place of seagulls, ) is a Chilean village located south of Pichilemu, at the mouth of the seasonal Nilahue Estuary, in the O'Higgins Region. Its economy is based on the production of sea salt, oysters, and mussels. The estuary is ...
salt ponds, in the
O'Higgins Region, Chile.
* The
Salineras de
Maras, Peru
Maras is a town in the Sacred Valley of the Incas, 40 kilometers north of Cusco, in the Cusco Region of Peru. The town is well known for its salt evaporation ponds, located towards Urubamba from the town center, which have been in use since ...
, in the
Cusco Region
Cusco, also spelled Cuzco (; qu, Qusqu suyu ), is a department and region in Peru and is the fourth largest department in the country, after Madre de Dios, Ucayali, and Loreto. It borders the departments of Ucayali on the north; Madre de D ...
.
* The saltworks of
Alcácer do Sal
Alcácer do Sal () is a municipality in Portugal, located in Setúbal District. The population in 2011 was 13,046, in an area of 1499.87 km2.
History Earliest settlement
There has been human settlement in the area for more than 40,000 ye ...
,
Comporta, and
Castro Marim
Castro Marim () is a town and a municipality in the southern region of Algarve, in Portugal. The population in 2011 was 6,747, in an area of 300.84 km2.
The current Mayor is Francisco Amaral, elected by the Social Democratic Party.
The mun ...
in
Portugal
Portugal, officially the Portuguese Republic ( pt, República Portuguesa, links=yes ), is a country whose mainland is located on the Iberian Peninsula of Southwestern Europe, and whose territory also includes the Atlantic archipelagos of ...
* The
El Caracol solar evaporator, on the outskirts of
Mexico City
Mexico City ( es, link=no, Ciudad de México, ; abbr.: CDMX; Nahuatl: ''Altepetl Mexico'') is the capital and largest city of Mexico, and the most populous city in North America. One of the world's alpha cities, it is located in the Valley o ...
,
Mexico
Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...
.
* The
Sečovlje
Sečovlje (; it, Sicciole) is a settlement in the Municipality of Piran in the Slovenian Littoral, Littoral region of Slovenia.
Name
The modern Slovene name ''Sečovlje'' is an artificial creation dating from after 1945. It was coined from the I ...
and
Strunjan salt ponds on the northern edge of the
Adriatic Sea
The Adriatic Sea () is a body of water separating the Italian Peninsula from the Balkan Peninsula. The Adriatic is the northernmost arm of the Mediterranean Sea, extending from the Strait of Otranto (where it connects to the Ionian Sea) to t ...
in
Slovenia
Slovenia ( ; sl, Slovenija ), officially the Republic of Slovenia (Slovene: , abbr.: ''RS''), is a country in Central Europe. It is bordered by Italy to the west, Austria to the north, Hungary to the northeast, Croatia to the southeast, an ...
.
* The
San Francisco Bay salt ponds in the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
, formerly operated by
Cargill
Cargill, Incorporated, is a privately held American global food corporation based in Minnetonka, Minnesota, and incorporated in Wilmington, Delaware. Founded in 1865, it is the largest privately held corporation in the United States in ter ...
, including
Charleston Slough
Charleston Slough is a former Leslie salt pond that is now reverting to marsh on the western shore of San Francisco Bay.
Environmental damage and recovery
In 1975 Leslie Salt owned the slough and used it for its salt water evaporation operatio ...
. Cargill has since ended salt production in the area, and most of the ponds are being restored to a more natural state.
* The
Dead Sea
The Dead Sea ( he, יַם הַמֶּלַח, ''Yam hamMelaḥ''; ar, اَلْبَحْرُ الْمَيْتُ, ''Āl-Baḥrū l-Maytū''), also known by other names, is a salt lake bordered by Jordan to the east and Israel and the West Bank ...
salt ponds in
the West Bank,
Israel
Israel (; he, יִשְׂרָאֵל, ; ar, إِسْرَائِيل, ), officially the State of Israel ( he, מְדִינַת יִשְׂרָאֵל, label=none, translit=Medīnat Yīsrāʾēl; ), is a country in Western Asia. It is situated ...
and
Jordan
Jordan ( ar, الأردن; tr. ' ), officially the Hashemite Kingdom of Jordan,; tr. ' is a country in Western Asia. It is situated at the crossroads of Asia, Africa, and Europe, within the Levant region, on the East Bank of the Jordan Rive ...
.
* The salt ponds in
Salina, Malta
Salina is a village in Malta. Salina borders Baħar iċ-Ċagħaq, Magħtab, Naxxar and St. Paul's Bay. Salina is mostly known for its salt pans and the Salina Catacombs
{{coord, 35.9441700, 14.4247200, display=title
The Salina Catacombs are a c ...
. The name of the village is the
Maltese word for salt pan.
* The Port Hedland, Dampier, Lake McLeod,
Useless Loop and
Onslow salt ponds in
Western Australia
Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...
.
* Yellow Walls,
Malahide
Malahide ( ; ) is an affluent coastal settlement in Fingal, County Dublin, Ireland, situated north of Dublin city. It has a village centre surrounded by suburban housing estates, with a population of over 17,000.
Malahide Castle dates from th ...
, Ireland; active from 1770 to 1837.
*
Lake Grassmere
Lake Grassmere / Kapara Te Hau is a New Zealand waituna-type lagoon in the northeastern South Island, close to Cook Strait. The lake is used for the production of salt.
Geography
Lake Grassmere, south of Blenheim and south of the mouth of ...
in New Zealand
* The ancient salt pans in
Marsala
Marsala (, local ; la, Lilybaeum) is an Italian town located in the Province of Trapani in the westernmost part of Sicily. Marsala is the most populated town in its province and the fifth in Sicily.
The town is famous for the docking of Gius ...
and
Trapani
Trapani ( , ; scn, Tràpani ; lat, Drepanum; grc, Δρέπανον) is a city and municipality (''comune'') on the west coast of Sicily, in Italy. It is the capital of the Province of Trapani. Founded by Elymians, the city is still an imp ...
, Sicily. Salt has been farmed here since the
Phoenician period, with archaeological evidence still present in nearby
Motya
Motya was an ancient and powerful city on San Pantaleo Island off the west coast of Sicily, in the Stagnone Lagoon between Drepanum (modern Trapani) and Lilybaeum (modern Marsala). It is within the present-day commune of Marsala, Italy.
Man ...
.
* The
Nature reserve of Margherita di Savoia, in Apulia, Italy. Known since antiquity, it's one of the largest in Europe.
Flamingos
Flamingos or flamingoes are a type of wading bird in the family Phoenicopteridae, which is the only extant family in the order Phoenicopteriformes. There are four flamingo species distributed throughout the Americas (including the Caribbea ...
often nest in the area.
* The salt works on the island of Great
Inagua
Inagua is the southernmost district of the Bahamas, comprising the islands of Great Inagua and Little Inagua. The headquarters for the district council are in Matthew Town.
History
The original settlers were the Lucayan people, who arrived som ...
owned by
Morton Salt
Morton Salt is an American food company producing salt for food, water conditioning, industrial, agricultural, and road/highway use. Based in Chicago, the business is North America's leading producer and marketer of salt. It is a subsidiary of h ...
.
* The salt harvesting by the Tsonga women of Baleni on the Small
Letaba River
The Letaba River ( af, Letabarivier), also known as Leţaba, Lehlaba or Ritavi, is a river located in eastern Limpopo Province, South Africa. It is one of the most important tributaries of the Olifants River.
Course
It starts at the confluence o ...
,
Limpopo
Limpopo is the northernmost province of South Africa. It is named after the Limpopo River, which forms the province's western and northern borders. The capital and largest city in the province is Polokwane, while the provincial legislature is ...
,
South Africa
South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...
.
Until
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
, salt was extracted from sea water in a unique way in Egypt near
Alexandria
Alexandria ( or ; ar, ٱلْإِسْكَنْدَرِيَّةُ ; grc-gre, Αλεξάνδρεια, Alexándria) is the second largest city in Egypt, and the largest city on the Mediterranean coast. Founded in by Alexander the Great, Alexandria ...
.
Salt, Grown On Sticks Harvested From Sea
''Popular Science'', March 1933 Posts were set out on the salt pans and covered with several feet of sea water. In time the sea water evaporated, leaving the salt behind on the post, where it was easier to harvest.
Production
Salt pans are shallow open, often metal, pans used to evaporate brine. They are usually found close to the source of the salt. For example, pans used in the solar evaporation of salt from sea water are usually found on the coast, while those used to extract salt from solution-mined brine will be found near to the brine shaft. In this case, extra heat is often provided by lighting fires underneath.
Gallery
File:2014 Cape Verde. Sal. Saltkratern (2).JPEG, Natural salt evaporation ponds at Pedra de Lume
Pedra de Lume is a village in the northeastern part of the island of Sal, Cape Verde. The village is situated on the east coast, about 5 km east of the island capital Espargos. It has a small port and a lighthouse, Farol de Pedra de Lume.
Sa ...
, Sal island
Sal (Portuguese for "salt") is an island in Cape Verde. Sal is a tourist destination with white sandy beaches and over 350 days of sunshine a year. It is one of the three sandy eastern islands of the Cape Verde archipelago in the central Atlantic ...
, Cape Verde
, national_anthem = ()
, official_languages = Portuguese
, national_languages = Cape Verdean Creole
, capital = Praia
, coordinates =
, largest_city = capital
, demonym ...
File:Marakkanam Salt Pans.JPG, A salt pan worker in a salt evaporation pond in Tamil Nadu
Tamil Nadu (; , TN) is a States and union territories of India, state in southern India. It is the List of states and union territories of India by area, tenth largest Indian state by area and the List of states and union territories of India ...
, India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
.
File:Lithium mine, Salar del Hombre Muerto, Argentina.jpg, Salt evaporation ponds at a lithium
Lithium (from el, λίθος, lithos, lit=stone) is a chemical element with the symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard conditions, it is the least dense metal and the least dense solid el ...
mine in Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
. The brine
Brine is a high-concentration solution of salt (NaCl) in water (H2O). In diverse contexts, ''brine'' may refer to the salt solutions ranging from about 3.5% (a typical concentration of seawater, on the lower end of that of solutions used for br ...
in this '' salar'' is rich in lithium, and the mine concentrates the brine in the ponds.
File:Lanzarote salt pans.jpg, Contemporary solar evaporation salt pans on the island of Lanzarote
Lanzarote (, , ) is a Spanish island, the easternmost of the Canary Islands in the Atlantic Ocean. It is located approximately off the north coast of Africa and from the Iberian Peninsula. Covering , Lanzarote is the fourth-largest of the i ...
at Salinas de Janubio
File:Solar Evaporation Ponds, Atacama Desert.jpg, Solar evaporation ponds in the Atacama Desert
The Atacama Desert ( es, Desierto de Atacama) is a desert plateau in South America covering a 1,600 km (990 mi) strip of land on the Pacific coast, west of the Andes Mountains. The Atacama Desert is the driest nonpolar desert in the ...
File:Fundacion Valle Salado511.JPG, Solar evaporation ponds in the Salt Valley of Añana, Spain
File:Vallesaladoanana.jpg, Solar evaporation ponds in the Salt Valley of Añana, Spain
Near town Pag - panoramio.jpg, Salt evaporation ponds at Pag, Croatia
, image_flag = Flag of Croatia.svg
, image_coat = Coat of arms of Croatia.svg
, anthem = "Lijepa naša domovino"("Our Beautiful Homeland")
, image_map =
, map_caption =
, capit ...
Salinas grandes-pala oxidada.jpg, Salt shovel from Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
See also
* Solar desalination
Solar desalination is a desalination technique powered by solar energy. The two common methods are direct (thermal) and indirect (photovoltaic).
History
Solar distillation has been used for thousands of years. Early Greek mariners and Persian ...
* Seawater greenhouse
A seawater greenhouse is a greenhouse structure that enables the growth of crops and the production of fresh water in arid regions which constitute about one third of the earth's land area. This in response to the global water scarcity and peak ...
* Evaporite
An evaporite () is a water-soluble sedimentary mineral deposit that results from concentration and crystallization by evaporation from an aqueous solution. There are two types of evaporite deposits: marine, which can also be described as ocea ...
References
External links
NASA page on salt ponds
Information on the San Francisco Bay salt ponds
Interactive satellite view
"Salt, Grown On Sticks Harvested From Sea"
''Popular Science'', March 1933
{{DEFAULTSORT:Salt Evaporation Pond
Ponds
Salt production
Economic geology
Primitive technology
Resource extraction