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Sea lettuce

Sea lettuce

Overview
The sea lettuces comprise the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Ulva, a group of edible green algae that is widely distributed along the coasts of the world's ocean
Ocean
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...

s. The type species within the genus Ulva is Ulva lactuca
Ulva lactuca
Ulva lactuca Linnaeus, a green alga in the division Chlorophyta, is the type species of the genus Ulva, also known by the common name sea lettuce.-Description:...

Linnaeus, "lactuca" meaning lettuce. Additionally, some species in the algae genus Monostroma
Monostroma
In taxonomy, Monostroma is a genus of algae, specifically of the Monostromataceae.-Scientific databases:* * *...

are known as slender sea lettuces.

Sea lettuce is eaten by a number of different sea animals, including manatee
Manatee
Manatees are large, fully aquatic, mostly herbivorous marine mammals sometimes known as sea cows...

s and the sea slugs known as sea hare
Sea hare
The clade Aplysiomorpha, commonly known as Sea hares or Sea Bags , are medium-sized to very large Opisthobranchia with a soft internal shell made of protein...

s.
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Encyclopedia
The sea lettuces comprise the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Ulva, a group of edible green algae that is widely distributed along the coasts of the world's ocean
Ocean
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...

s. The type species within the genus Ulva is Ulva lactuca
Ulva lactuca
Ulva lactuca Linnaeus, a green alga in the division Chlorophyta, is the type species of the genus Ulva, also known by the common name sea lettuce.-Description:...

Linnaeus, "lactuca" meaning lettuce. Additionally, some species in the algae genus Monostroma
Monostroma
In taxonomy, Monostroma is a genus of algae, specifically of the Monostromataceae.-Scientific databases:* * *...

are known as slender sea lettuces.

Sea lettuce is eaten by a number of different sea animals, including manatee
Manatee
Manatees are large, fully aquatic, mostly herbivorous marine mammals sometimes known as sea cows...

s and the sea slugs known as sea hare
Sea hare
The clade Aplysiomorpha, commonly known as Sea hares or Sea Bags , are medium-sized to very large Opisthobranchia with a soft internal shell made of protein...

s. Many species of sea lettuce are a food source for humans in Scandinavia
Scandinavia
Scandinavia is a cultural, historical and ethno-linguistic region in northern Europe that includes the three kingdoms of Denmark, Norway and Sweden, characterized by their common ethno-cultural heritage and language. Modern Norway and Sweden proper are situated on the Scandinavian Peninsula,...

, Great Britain
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...

, Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

, China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

, and Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

 (where this food is known as aosa). Sea lettuce as a food for humans is eaten raw in salad
Salad
Salad is any of a wide variety of dishes, including vegetable salads; salads of pasta, legumes, eggs, or grains; mixed salads incorporating meat, poultry, or seafood; and fruit salads. They may include a mixture of cold and hot, often including raw vegetables or fruits.Green salads include leaf...

s and cooked in soup
Soup
Soup is a generally warm food that is made by combining ingredients such as meat and vegetables with stock, juice, water, or another liquid. Hot soups are additionally characterized by boiling solid ingredients in liquids in a pot until the flavors are extracted, forming a broth.Traditionally,...

s. It is high in protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

, soluble dietary fiber
Dietary fiber
Dietary fiber, dietary fibre, or sometimes roughage is the indigestible portion of plant foods having two main components:* soluble fiber that is readily fermented in the colon into gases and physiologically active byproducts, and* insoluble fiber that is metabolically inert, absorbing water as it...

, and a variety of vitamin
Vitamin
A vitamin is an organic compound required as a nutrient in tiny amounts by an organism. In other words, an organic chemical compound is called a vitamin when it cannot be synthesized in sufficient quantities by an organism, and must be obtained from the diet. Thus, the term is conditional both on...

s and mineral
Mineral
A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...

s, especially iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

.

Individual blades of Ulva can grow to be more than 400mm (16") in size, but this only occurs when the plants are growing in sheltered areas.

In August 2009, unprecedented amounts of these algae washed up on the beaches of Brittany
Brittany
Brittany is a cultural and administrative region in the north-west of France. Previously a kingdom and then a duchy, Brittany was united to the Kingdom of France in 1532 as a province. Brittany has also been referred to as Less, Lesser or Little Britain...

, France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

, causing a major public health scare as it decomposed. The rotting leaves produced large quantities of hydrogen sulphide, a toxic gas. In one incident near Saint-Michel-en-Grève
Saint-Michel-en-Grève
Saint-Michel-en-Grève is a commune in the Côtes-d'Armor department in Bretagne in northwestern France.In 2009 vast quantities of Ulva lactuca washed up on the beach at Saint Michel causing the deaths of a horse and cleanup crew truck driver.-Population:...

, a horse rider lost consciousness and his horse died after breathing the seaweed fumes; in another, a lorry driver driving a load of decomposing sea lettuce passed out, crashed and died, with toxic fumes claimed to be the cause. Environmentalists blamed the phenomenon on excessive use of nitrates by pig and poultry farmers.

Species


Species in the genus Ulva include:
  • Ulva lactuca
    Ulva lactuca
    Ulva lactuca Linnaeus, a green alga in the division Chlorophyta, is the type species of the genus Ulva, also known by the common name sea lettuce.-Description:...

  • Ulva pertusa
  • Ulva fasciata
  • Ulva rigida
  • Ulva linza
    Ulva linza
    Ulva linza Linnaeus is a green alga in the division Chlorophyta, is the type species of the genus Ulva.-Description:Ulva linza is a green alga that grows in bright green clusters of tubes or flat strips. It is found in muddy estuaries attached to pebbles or docks.-Further reading:* Hayden, H.S.,...

  • Ulva intestinalis
    Ulva intestinalis
    Ulva intestinalis is a green alga in the division Chlorophyta, of the genus Ulva, also known by the common names gutweed and grass kelp. Until they were reclassified by genetic work completed in the early 2000s, the tubular members of the genus Ulva were in the genus Enteromorpha.-References:...

  • Ulva prolifera
  • Ulva rilomacedonica - in rivers

External links