A group of unicellular and multicellular simple organisms regarded by the majority of botanists as plants although there is some doubt, as this family includes plankton. While many members of the family are microscopic and colonial, they include some of the biggest plants known such as Bull Kelp (Laminaria) much loved by sea-otters.
Algae were in existence for at least two billion years before the appearance of man and will certainly outlive him. The plant has an affinity for water and is the most prolific organism to be found in the oceans, as well as existing in fresh water and damp terrestrial habitats. It can be found around smoke-holes (undersea volcanic fissures) and in Antarctic ice, in fresh water reservoirs – where they form the dreaded blue/green blooms which become toxic as they degrade as well as forming blooms in holiday areas making the water look like pea-soup and frightening off tourists.
Algae is the single most important source of oxygen on the planet and is the basis for the marine food chain. The Aztecs collected it as a food and a blood purifier, the Irish harvested it at low tide in the Atlantic, and it has featured as an important medicinal treatment in Chinese pharmacology. Algae is farmed in Europe, North America, China and Japan as a health supplement. Spirulina, extracted from a micro-algae, contains no less than 18 amino acids including eight that the body cannot reproduce from its own resources and has to be replaced daily by food intake. It is rich in beta-carotene, Vitamin E and iron. Spirulina is very popular with athletes, body-builders, and slimmers as they require maximum nutrition from a modest amount of food. Recent research on the plant, indicates positive properties in inhibiting HIV and reducing blood pressure. The effect on the thyroid regulates the metabolic rate and will prove of importance to weight-watchers as well as engendering a general sense of well being.
In Chinese medicine Kelp (Laminaria saccharina) is recommended for the treatment of Scrofula, oedema (fluid retention), goiter (enlargement of the thyroid gland), topical tumours and swollen testicles. Sargassum, another seaweed member of the algae, is used to reduce ovarian cysts, breast nodes, lymph nodes and lipomas (benign fat tumours).
Porphyra is present in the Chinese Materia Medica as a treatment for Beri-Beri and infections of the urinary system.
Extracts from algae are used as preservatives in flavoured milk drinks, yoghurts and beer.
The most prominent current interest in algae is as a bio-diesel.