Ulva lactuca

Ulva lactuca

Sea lettuce (Ulva lactuca L., 1753) is a green alga belonging to the Ulvaceae family.

Systematics –
From a systematic point of view it belongs to:
Eukaryota Domain,
Kingdom Plantae,
Sub-kingdom Viridiplantae,
Chlorophyta Division,
Ulvophyceae class,
Order Ulvales,
Ulvaceae family,
Genus Ulva,
U. lactuca species.
The terms are synonymous:
– Phycoseris fasciata (Delile) Mont., 1856;
– Phyllona lactuca (L.) F.H.Wiggers, 1780;
– Ulva fasciata Delile;
– Ulva lactuca f. fasciata (Delile) Hering, 1846;
– Ulva lactuca subsp. fasciata (Delile) Hering, 1846;
– Ulva lactucaefolia S.F.Gray, 1821.
Within this range the following varieties are recognized:
– Ulva lactuca var. lacinulata (Kütz.) W.R.Taylor, 1960;
– Ulva lactuca var. lactuca;
– Ulva lactuca var. latissima;
– Ulva lactuca var. myriotrema (P.L.Crouan & H.M.Crouan) Bornet, 1843;
– Ulva lactuca var. rigida.

Etymology –
The term Ulva comes from the Latin ulva, plants of the Cyperaceae, therefore similar to an ulva.
The specific epithet lactuca comes from lettuce, which in turn comes from the Latin lac, láctis latte: due to the abundant white latex present in plants of this genus: therefore similar to lettuce.

Geographic Distribution and Habitat –
Ulva lactuca is a green alga with worldwide distribution; it is present in the seas of: Europe, North America (west and east coasts), Central America, Caribbean Islands, South America, Africa, Indian Ocean Islands, Southwest Asia, China, Pacific Islands, Australia and New Zealand . It is a common alga in the Mediterranean Sea and in cold or temperate seas.
Its marine habitat is that of rocks and other algae of the littoral and sublittoral of the coasts. This alga is particularly prolific in areas where nutrients are abundant. Its proliferation can denote the presence of high levels of nitrates from agricultural activity. In these cases, the result is that large quantities of Ulva lactuca are washed ashore on the beaches, where their biodegradation produces methane, hydrogen sulfide and other gases.

Description –
Sea lettuce is a seaweed up to 30 centimeters high, translucent, with a bright bright green color. It has a thin, not very large, lamellar phyllodes, fixed to a helical peduncle.
This species is formed by two layers of cells arranged in an irregular way. The chloroplast is cup-shaped in some references but as a parietal plate in others with one to three pyrenoids.
The adult diploid plant produces haploid zoospores by meiosis, these settle and grow to form male and female haploid plants similar to diploid plants. When these haploid plants release gametes, they combine to produce the zygote which germinates and grows to produce the diploid plant.

Cultivation –
The Ulva lactuca is an alga that grows in rocky coasts and sub-coasts and which in certain environmental conditions can spread over large areas.
A high proliferation of this alga is to be linked to the eutrophication of the coasts due to the greater presence of nitrates, often derived from agriculture or livestock farms.
Under these conditions the decomposing thallus of this alga produces large quantities of hydrogen sulfide, a toxic gas which, like hydrogen cyanide, inhibits cytochrome c oxidase, inhibiting cellular respiration and causing critical cellular hypoxia.
There have been illnesses or even deaths of both animals and people as a result of breathing in the fumes developed by decomposing algae.
Under ordinary conditions, the seaweed is harvested in spring and autumn, or during the seasons in which it has its best color that reflects the richness of nutrients.

Customs and Traditions –
Ulva lactuca is an alga used in some parts of the world in soups and salads. In Hawaii it is called limu pālahala and is eaten in different ways: mixed with other seaweed, salted and served with raw fish, boiled in water and served as a soup, or served with chilli, onions, soy sauce and sugar. In addition, in these areas it has traditional uses as a fertilizer and as an ornament for the hula (Polynesian dance). When the U. lactuca is used for the hula it is called limu pāpahapaha.
In Japan, where it is called aosa (石 蓴), it is consumed as a food. Also in Scotland it is used for soups and salads. It is eaten raw, as a salad in Scandinavia, Denmark, Ireland, but also in Indonesia. In Italy it is used for the preparation of sea zeppolelle or seaweed fritters, a typical Neapolitan dish.
Like all marine algae, it is very rich in mineral salts and trace elements. In particular it is characterized by the presence of calcium (3g / 100g) and magnesium (2.8g / 100g). Contains all 8 essential amino acids. It has a moderate vitamin content (provitamin A, group B and vitamin C) and essential omega-3 fatty acids (α-linolenic acid C18: 3).
It also contains water-soluble polysaccharides which consist of sulfur molecules of uronic acid, which cannot be broken down by digestive enzymes. Like the starches of terrestrial plants, the starches of green macroalgae consist of amylaceous polysaccharides and amylopectins, which have similar properties to the starches found in potatoes, although in the latter the degree of polymerization is considerably lower. The starch elements of Ulva lactuca dissolve easily in water without becoming sticky.
In the medical field, this alga (like other algae) becomes part of food supplements.

Preparation Method –
Sea lettuce is an alga that is used in the food sector in various food traditions around the world and, especially in recent times, in the medical field as a food supplement.
It is eaten mixed with other seaweed, salted and served with raw fish, or boiled in water and served as a soup, or served with chilli, onions, soy sauce and sugar.
In Japan it is consumed as a food.
In Scotland it is used to prepare soups and salads while eaten raw, as a salad in Scandinavia, Denmark, Ireland, but also in Indonesia. In Italy it is used for the preparation of sea zeppolelle or seaweed fritters, a typical Neapolitan dish.
In the medical field, this alga becomes part of food supplements and is sold in various formulations in pharmacies or specialty stores.

Guido Bissanti

Sources
– Acta Plantarum – Flora of the Italian Regions.
– Wikipedia, the free encyclopedia.
– GBIF, the Global Biodiversity Information Facility.
– Useful Tropical Plants Database.
– Conti F., Abbate G., Alessandrini A., Blasi C. (ed.), 2005. An annotated checklist of the Italian vascular flora, Palombi Editore.
– Pignatti S., 1982. Flora of Italy, Edagricole, Bologna.
– Treben M., 2000. Health from the Lord’s Pharmacy, Advice and experiences with medicinal herbs, Ennsthaler Editore.
Photo source:
– https://inaturalist-open-data.s3.amazonaws.com/photos/195574084/original.jpg

Warning: Pharmaceutical applications and alimurgical uses are indicated for informational purposes only, they do not represent in any way a medical prescription; therefore no responsibility is taken for their use for curative, aesthetic or food purposes.