Sea lettuce

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Sea lettuce
Meersalat-Ulva-lactuca.jpg
Ulva lactuca
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Division: Chlorophyta
Class: Ulvophyceae
Order: Ulvales
Family: Ulvaceae
Genus: Ulva
Linnaeus, 1753
Species

See text

Synonyms [1]
  • Enteromorpha Link in Nees, 1820.
Ulva intestinalis Tufts of gutweed in Gullmarsfjorden at Samstad 1.jpg
Ulva intestinalis

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, [1] which are known under the common name green nori. [2]

Contents

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. [3] [4]

Nutrition and contamination

Sea lettuce is eaten by a number of different sea animals, including manatees and the sea slugs known as sea hares. [5]

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. [6] Enhances flavor and fortifies bread when chopped and mixed into the dough before baking. [7] [8]

Contamination with toxic heavy metals at certain sites where it can be collected makes it dangerous for human consumption. [6]

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. [9] 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: [10]

Accepted species
Nomina dubia

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. [11] 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. [12]

See also

References

  1. 1 2 Hillary S. Hayden; Jaanika Blomster; Christine A. Maggs; Paul C. Silva; Michael J. Stanhope & J. Robert Waaland (2003). "Linnaeus was right all along: Ulva and Enteromorpha are not distinct genera" (PDF). European Journal of Phycology. 38 (3): 277–294. CiteSeerX   10.1.1.330.5106 . doi:10.1080/1364253031000136321. ISSN   1469-4433. S2CID   18856367. Archived from the original (PDF) on 2011-08-07.
  2. ↑ M.D. Guiry & G.M. Guiry (2012). "Enteromorpha Link in Nees, 1820". AlgaeBase. National University of Ireland. Retrieved February 11, 2012.
  3. ↑ "Sea lettuce | green algae". Encyclopedia Britannica. Retrieved 2021-02-23.
  4. ↑ Burrows, E.M. 1991. Seaweeds of the British Isles. Volume 2 Chlorophyta. Natural History Museum, ISBN   0-565-00981-8
  5. ↑ Carefoot, T.H. (1979). "Artificial diets for sea hares". Canadian Journal of Zoology. 57 (11): 2271–2273. doi:10.1139/z79-295.
  6. 1 2 Yaich, H.; Garna, H.; Besbes, S.; Paquot, M.; Blecker, C.; Attia, H. (2011), "Chemical composition and functional properties of Ulva lactuca seaweed collected in Tunisia", Food Chemistry, 128 (4): 895–901, doi:10.1016/j.foodchem.2011.03.114, S2CID   85407130
  7. ↑ D-S, Stef; Rivis, A; Trasca, TI; et al. (2022). "The Enrichment of Bread with Algae Species". Scientific Papers Series D: Animal Science. 65 (1): 558–563. Retrieved 2026-01-28.
  8. ↑ Kort, Robin (2023). The Coastal Forager’s Cookbook (Hardback). Touchwood Editions. ISBN   978-1771514088.
  9. ↑ "Seaweed suspected in French death". BBC. September 7, 2009. Retrieved September 7, 2009.
  10. ↑ M.D. Guiry (2012). Guiry MD, Guiry GM (eds.). "Ulva Linnaeus, 1753". AlgaeBase. National University of Ireland, Galway . World Register of Marine Species . Retrieved February 11, 2012.
  11. ↑ 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
  12. ↑ 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 Society57;458 - 478.

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