Sea lettuce | |
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Ulva lactuca | |
Scientific classification | |
Clade: | Viridiplantae |
Division: | Chlorophyta |
Class: | UTC clade |
Order: | Ulvales |
Family: | Ulvaceae |
Genus: | Ulva Linnaeus, 1753 |
Species | |
See text | |
Synonyms [1] | |
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The sea lettuces comprise the genus Ulva, a group of edible green algae that is widely distributed along the coasts of the world's oceans. The type species within the genus Ulva is Ulva lactuca , lactuca being Latin for "lettuce". The genus also includes the species previously classified under the genus Enteromorpha, [1] the former members of which are known under the common name green nori. [2]
Individual blades of Ulva can grow to be more than 400 mm (16 in) in size, but this occurs only when the plants are growing in sheltered areas. A macroscopic alga which is light to dark green in colour, it is attached by disc holdfast. Their structure is a leaflike flattened thallus. [3] [4]
Sea lettuce is eaten by a number of different sea animals, including manatees and the sea slugs known as sea hares. Many species of sea lettuce are a food source for humans in Scandinavia, Great Britain, Ireland, China, and Japan (where this food is known as aosa). Sea lettuce as a food for humans is eaten raw in salads and cooked in soups. It is high in protein, soluble dietary fiber, and a variety of vitamins and minerals, especially iron. [5] However, contamination with toxic heavy metals at certain sites where it can be collected makes it dangerous for human consumption. [5]
Sea lettuce species are commonly found in the saltwater aquarium trade, where the plants are valued for their high nutrient uptake and edibility. Many reef aquarium keepers use sea lettuce species in refugia or grow it as a food source for herbivorous fish. Sea lettuce is very easy to keep, tolerating a wide range of lighting and temperature conditions. In the refugium, sea lettuce can be attached to live rock or another surface, or simply left to drift in the water.
In August 2009, unprecedented amounts of these algae washed up on the beaches of Brittany, France, causing a major public health scare as it decomposed. The rotting leaves produced large quantities of hydrogen sulfide, a toxic gas. In one incident near Saint-Michel-en-Grève, 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. [6] Environmentalists blamed the phenomenon on excessive nitrogenous compounds washed out to sea from improper disposal of pig and poultry animal waste from industrial farms.
Species in the genus Ulva include: [7]
A newly discovered Indian endemic species of Ulva with tubular thallus indistinguishable from Ulva intestinalis has been formally established in 2014 as Ulva paschima Bast. [8] Ten new species have been discovered in New Caledonia: Ulva arbuscula, Ulva planiramosa, Ulva batuffolosa, Ulva tentaculosa, Ulva finissima, Ulva pluriramosa, Ulva scolopendra and Ulva spumosa. [9]
Ulva lactuca, also known by the common name sea lettuce, is an edible green alga in the family Ulvaceae. It is the type species of the genus Ulva. A synonym is U. fenestrata, referring to its "windowed" or "holed" appearance, Despite the name, it is not a lettuce.
Gracilaria, also known as irish moss or ogonori, is a genus of red algae in the family Gracilariaceae. It is notable for its economic importance as an agarophyte meaning that it is used to make agar, as well as its use as a food for humans and various species of shellfish. Various species in the genus are cultivated among Asia, South America, Africa and Oceania. They produce over 90% of the world's agar.
Codium is a genus of edible green macroalgae under the order Bryopsidales. The genus name is derived from a Greek word that pertains to the soft texture of its thallus. One of the foremost experts on Codium taxonomy was Paul Claude Silva at the University of California, Berkeley. Silva was able to describe 36 species for the genus, and in honor of his work on Codium, the species C. silvae was named after the late professor.
Chordariaceae is a family of brown algae. Members of this family are may be filamentous, crustose with fused cells at the base, or they may be terete and differentiated into a central medulla and an outer photosynthetic cortex. They have a sporphytic thallus usually aggregated to form a pseudo-parenchyma.
Vaucheria is a genus of Xanthophyceae or yellow-green algae known as water felt. It is one of only two genera in the family Vaucheriaceae. The type species of the genus is Vaucheria disperma.
Ulva intestinalis is a green alga in the family Ulvaceae, known by the common names sea lettuce, green bait weed, gutweed, and grass kelp. Until they were reclassified by genetic work completed in the early 2000s, the tubular members of the sea lettuce genus Ulva were placed in the genus Enteromorpha.
Rhodymenia is a genus of red algae, containing the following species:
Ulva linza is a green alga in the family Ulvaceae that can be found in British Isles.
Plocamium is a genus of red algae in the family Plocamiaceae. It contains around 40 species and has a cosmopolitan distribution in temperate seas, although it is most diverse in the southern hemisphere. It is widely distributed in tropical and also warm-temperate and cold-temperate seas, such as northern Europe, the northern Arabian Sea and western Australia. They are also found in the Antarctic regions of Admiralty Bay and Terra Nova Bay.
Ulva acanthophora is a species of benthic subtropical seaweed in the Ulvaceae family that can be found in California and Mexico.
Ulva chaetomorphoides is a species of tropical and benthic seaweed in Ulvaceae family that can be found in Gulf of Mexico and European waters.
Blidingia marginata is a species of seaweed in the Kornmanniaceae family.
Hypnea is a genus of red algae, and a well known carrageenophyte.
Christine Adair Maggs is a British phycologist. Formerly Executive Dean of the Faculty of Science & Technology at Bournemouth University, she was the first Chief Scientist of the Joint Nature Conservation Committee, retiring in 2022. She is now an independent non-executive Director of Ocean Harvest Technology https://oceanharvesttechnology.com/corporate-governance/board-of-directors/
Phyllophoraceae is a family of red algae in the order Gigartinales.
Beer,Sven. 2023 Photosynthetic traits of ubiquitous and prolific macroalga Ulva (Chlorophyta): a review. European Journal of Phycology58:390 - 398.