Sea lettuce
Edible green algae with culinary uses and toxicity risks.
Sea lettuce comprises the genus Ulva, a group of edible green algae widely distributed along the coasts of the world's oceans. The type species is Ulva lactuca, with lactuca being Latin for 'lettuce'. The genus also includes species previously classified under Enteromorpha, known as green nori.
- field
- Marine botany / Phycology
- known_for
- Edible green algae, source of food and health concerns
- type_species
- Ulva lactuca
- common_names
- Sea lettuce, green nori, aosa
- habitat
- Coasts of the world's oceans
Lore & Background
It is a macroscopic alga, light to dark green, attached by a disc holdfast, with a leaflike flattened thallus. Sea lettuce is eaten by manatees and sea hares, and by humans in Scandinavia, Great Britain, Ireland, China, and Japan, where it is known as aosa. It is consumed raw in salads or cooked in soups, and is high in protein, soluble dietary fiber, and vitamins and minerals, especially iron. It can enhance flavor and fortify bread when chopped and mixed into dough.
Reader's Guide
Sea lettuce holds significance as a widely distributed edible alga with both nutritional benefits and potential dangers. Its use as human food spans multiple cultures, and it is valued for its protein, fiber, and iron content. However, contamination with toxic heavy metals at certain collection sites makes it dangerous for consumption. Environmentalists linked the blooms to nitrogenous compounds from agricultural runoff. The genus also includes newly discovered species, such as the Indian endemic Ulva paschima and ten new species from New Caledonia, highlighting ongoing taxonomic research. Its legacy includes both its role as a food source and as a marker of environmental pollution.
Did You Know?
- The type species Ulva lactuca has the Latin lactuca meaning 'lettuce'.
- Ten new species of Ulva were discovered in New Caledonia.
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