Sea lettuce

The sea lettuces comprise the genus Ulva, a group of edible green algae that are 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, which are known under the common name green nori.

Description 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.Burrows, E.M. 1991. Seaweeds of the British Isles. Volume 2 Chlorophyta. Natural History Museum,

Nutrition and contamination 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. Enhances flavor and fortifies bread when chopped and mixed into the dough before baking.

Contamination with toxic heavy metals at certain sites where it can be collected makes it dangerous for human consumption.

Health concerns 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. Environmentalists blamed the phenomenon on excessive nitrogenous compounds washed out to sea from improper disposal of pig and poultry slurry from industrial farms, and from chemical products and slurry used as fertilisers in arable farming.

Species Species in the genus Ulva include:

Accepted species

Ulva acanthophora (Kützing) Hayden, Blomster, Maggs, P.C. Silva, Stanhope & J.R. Waaland, 2003 Ulva anandii Amjad & Shameel, 1993 Ulva arasakii Chihara, 1969 Ulva atroviridis Levring, 1938 Ulva australis Areschoug, 1854 Ulva beytensis Thivy & Sharma, 1966 Ulva bifrons Ardré, 1967 Ulva brevistipita V.J. Chapman, 1956 Ulva burmanica (Zeller) De Toni, 1889 Ulva californica Wille, 1899 Ulva chaetomorphoides (Børgesen) Hayden, Blomster, Maggs, P.C. Silva, M.J. Stanhope & J.R. Waaland, 2003 Ulva clathrata (Roth) C. Agardh, 1811 Ulva compressa Linnaeus, 1753 Ulva conglobata Kjellman, 1897 Ulva cornuta Lightfoot, 1777 Ulva covelongensis V. Krishnamurthy & H. Joshi, 1969 Ulva crassa V.J. Chapman, 1956 Ulva crassimembrana (V.J. Chapman) Hayden, Blomster, Maggs, P.C. Silva, M.J. Stanhope & J.R. Waaland, 2003 Ulva curvata (Kützing) De Toni, 1889 Ulva denticulata P.J.L. Dangeard, 1959 Ulva diaphana Hudson, 1778 Ulva elegans Gayral, 1960 Ulva enteromorpha Le Jolis, 1863 Ulva erecta (Lyngbye) Fries Ulva expansa (Setchell) Setchell & N.L. Gardner, 1920 Ulva fasciata Delile, 1813 Ulva flexuosa Wulfen, 1803 Ulva geminoidea V.J. Chapman, 1956 Ulva gigantea (Kützing) Bliding, 1969 Ulva grandis Saifullah & Nizamuddin, 1977 Ulva hookeriana (Kützing) Hayden, Blomster, Maggs, P.C. Silva, M.J. Stanhope & J.R. Waaland Ulva hopkirkii (M'Calla ex Harvey) P. Crouan & H. Crouan Ulva howensis (A.H.S. Lucas) Kraft, 2007 Ulva indica Roth, 1806 Ulva intestinalis Linnaeus, 1753 Ulva intestinaloides (R.P.T. Koeman & Hoek) Hayden, Blomster, Maggs, P.C. Silva, M.J. Stanhope & J.R. Waaland, 2003 Ulva javanica N.L. Burman, 1768 Ulva kylinii (Bliding) Hayden, Blomster, Maggs, P.C. Silva, M.J. Stanhope & J.R. Waaland, 2003 Ulva lactuca Linnaeus, 1753 Ulva laetevirens J.E. Areschoug, 1854 Ulva laingii V.J. Chapman, 1956 Ulva linearis P.J.L. Dangeard, 1957 Ulva linza Linnaeus, 1753 Ulva lippii Lamouroux Ulva litoralis Suhr ex Kützing Ulva littorea Suhr Ulva lobata (Kützing) Harvey, 1855 Ulva maeotica (Proshkina-Lavrenko) P.M.Tsarenko, 2011 Ulva marginata (J. Agardh) Le Jolis Ulva micrococca (Kützing) Gobi Ulva mutabilis Föyn, 1958 Ulva neapolitana Bliding, 1960 Ulva nematoidea Bory de Saint-Vincent, 1828 Ulva ohnoi Hiraoka & Shimada, 2004 Ulva olivascens P.J.L. Dangeard Ulva pacifica Endlicher Ulva papenfussii Pham-Hoang Hô, 1969 Ulva parva V.J. Chapman, 1956 Ulva paschima Bast Ulva patengensis Salam & Khan, 1981 Ulva percursa (C. Agardh) C. Agardh Ulva pertusa Kjellman, 1897 Ulva phyllosa (V.J. Chapman) Papenfuss Ulva polyclada Kraft, 2007 Ulva popenguinensis P.J.L. Dangeard, 1958 Ulva porrifolia (S.G. Gmelin) J.F. Gmelin Ulva profunda W.R. Taylor, 1928 Ulva prolifera O.F.Müller, 1778 Ulva pseudocurvata Koeman & Hoek, 1981 Ulva pseudolinza (R.P.T. Koeman & Hoek) Hayden, Blomster, Maggs, P.C. Silva, M.J. Stanhope & J.R. Waaland, 2003 Ulva pulchra Jaasund, 1976 Ulva quilonensis Sindhu & Panikkar, 1995 Ulva radiata (J. Agardh) Hayden, Blomster, Maggs, P.C. Silva, M.J. Stanhope & J.R. Waaland, 2003 Ulva ralfsii (Harvey) Le Jolis, 1863 Ulva ranunculata Kraft & A.J.K. Millar, 2000 Ulva reticulata Forsskål, 1775 Ulva rhacodes (Holmes) Papenfuss, 1960 Ulva rigida C. Agardh, 1823 Ulva rotundata Bliding, 1968 Ulva saifullahii Amjad & Shameel, 1993 Ulva serrata A.P.de Candolle Ulva simplex (K.L. Vinogradova) Hayden, Blomster, Maggs, P.C. Silva, M.J. Stanhope & J.R. Waaland, 2003 Ulva sorensenii V.J. Chapman, 1956 Ulva spinulosa Okamura & Segawa, 1936 Ulva stenophylla Setchell & N.L. Gardner, 1920 Ulva sublittoralis Segawa, 1938 Ulva subulata (Wulfen) Naccari Ulva taeniata (Setchell) Setchell & N.L. Gardner, 1920 Ulva tanneri H.S. Hayden & J.R. Waaland, 2003 Ulva tenera Kornmann & Sahling Ulva torta (Mertens) Trevisan, 1841 Ulva tuberosa Palisot de Beauvois Ulva uncialis (Kützing) Montagne, 1850 Ulva uncinata Mohr Ulva uncinata Mertens Ulva usneoides Bonnemaison Ulva utricularis (Roth) C. Agardh Ulva utriculosa C. Agardh Ulva uvoides Bory de Saint-Vincent Ulva ventricosa A.P.de Candolle

Nomina dubia Ulva costata Wollny, 1881 Ulva repens Clemente, 1807 Ulva tetragona A.P.de Candolle, 1807

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.BAST, F., JOHN, A.A. AND BHUSHAN, S. 2014. Strong endemism of bloom-forming tubular Ulva in Indian west coast, with description of Ulva paschima Sp. Nov. (Ulvales, Chlorophyta. PLoS ONE 9(10): e109295. doi:10.1371/journal.pone.0109295 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.Lagourgue, L et al 2022 The new species of Ulva (Ulvophyceae, Chlorophyta) discovered in New Caledonia genetic and morphological and diversity, and bloom potential. British Phycological Society 57;458 - 478.

Sea lettuce

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