sea lettuce

Sea lettuce
Ulva lactuca
Scientific classification
Domain:	Eukarya
Kingdom:	Protista
Phylum:	Chlorophyta
Class:	Ulvophyceae
Order:	Ulvales
Family:	Ulvaceae
Genus:	Ulva Linnaeus, 1753
Species
See text

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 Linnaeus, "lactuca" meaning lettuce. Additionally, some species in the algae genus Monostroma are known as slender sea lettuces.

Sea lettuce is eaten by a number of different sea animals, including manatees and the sea slugs that are known as sea hares. Many species of sea lettuce are a food source for humans in areas that include 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.

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

In August 2009, unprecedented amounts of this alga 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 sulphide, 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^[1]. Environmentalists blamed the phenomenon on excessive use of nitrates by pig and poultry farmers.

Species

Species in the genus Ulva include:

• Ulva lactuca
• Ulva pertusa
• Ulva fasciata
• Ulva rigida
• Ulva linza

See also

• Seaweed

References

1. ^ "Seaweed suspected in French death". BBC. September 7, 2009. http://news.bbc.co.uk/1/hi/world/europe/8242649.stm. Retrieved September 7, 2009. 

External links

• Marine botany: Ulva
• C. Tanner & Robert Wilkes (2005-02-17). "Ulva Linnaeus 1753: 1163". AlgaeBase. http://www.algaebase.org/GeneraDetail.lasso?genus_id=33. 
• Toxic seaweed clogs French coast (BBC)

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