What are algae?
Algae are a photosynthetically diverse group of organisms, including the cyanobacteria (previously called blue-green algae), ranging in size from bacteria (0.2-2 microns) to giant kelps (tens [40]of metres). They are nearly all aquatic. They are classified in two Kingdoms. Red and green algae are included in the Kingdom Plantae, the Brown algae and the Diatoms are in the Kingdom Chromista.
The Cyanobacteria are now generally included in the Kingdom Monera. There are clearly problems at least with the larger forms and the present classification includes some elements of NOT being an animal, a plant or a fungus.
There are 6 phyla plus the Cyanobacteria (blue-green algae) which are included here both for historical reasons and convenience.
| Diatoms and chrysophytes | Chrysophyta |
| Dinoflagellates | Pyrrophyta |
| Euglenoids | Euglenophyta |
| Red algae | Rhodophyta |
| Brown algae | Phaeophyta |
| Green algae | Chlorophyta |
| Blue green algae | Cyanobac |
Useful species, common names, some of their uses?
| Species | Common name | Uses |
|---|---|---|
| acanthopeltis | agar | |
| Ahnfeltia plicata in USSR |
agar | |
| Anaebaena-Azolla symbiosis |
“green manure” | Inoculation of 0.2 kg of Azolla per hectare is equivalent to 30 kg/hectare of commercial nitrogen fertilizer. Not as popular now because we have found that Azolla growth is limited by phosphate, which is non-renewable. Next break is low-phosphorus requiring Azolla |
| Ascophyllum nodosum (bladder wrack) |
alginates | thickening agents (fruit drinks and salad dressing), colloid stabilizers in food (ice creams, sherbets and cheeses), textile, cosmetic, pharmaceutical, paper and welding industries. |
| Calcareous algae | to reduce soil acidity. |
|
| Caulerpa racemosa (Nama) in Fiji |
food | |
| Chlamydomonas and other soil algae |
soil amendment by making mucilage that loosen compacted soil. |
|
| Chlorella | only microscopic green used commercially |
|
| Chondrus crispus (Irish Moss) |
agar, carrageenan | |
| Codium geppii (Sagati) in Fiji |
food | |
| Diatom fossils (diatomaceous earth, diatomite) |
flea killers, embalming compounds, enamel polishes, diatomaceous bricks, to filter sewage in UK from 1976, to filter sugar cane liquors from 1914; Nobel stabilized nitroglycerine. |
|
| Durvillaea (Australia & Chile) |
alginates | thickening agents (fruit drinks and salad dressing), colloid stabilizers in food (ice creams, sherbets and cheeses), textile, cosmetic, pharmaceutical, paper and welding industries. |
| Ecklonia | alginates | thickening agents (fruit drinks and salad dressing), colloid stabilizers in food (ice creams, sherbets and cheeses), textile, cosmetic, pharmaceutical, paper and welding industries. |
| Eucheuma in Philippines |
carrageenan | |
| Furcillaria fastigiata in Denmark |
agar | |
| Gelidium amansii in Japan |
agar | |
| Gelidium arborescens in USA |
agar | |
| Gelidium cartillagineum in USA |
agar | |
| Gelidium latifolium in Ireland. |
agar | |
| Gelidium nudifrons in USA. |
agar | |
| Gelidium pulchellum Ireland |
agar | |
| Gigartina clavifera in New Zealand |
carrageenan | |
| Gigartina mamillosa (very similar and known as Irish Moss). |
carrageenan | |
| Gigartina undulata in New Zealand |
carrageenan | |
| Gracilaria (Lumicevata) in Fiji |
food | |
| Hypnea (Lumiwawa) in Fiji |
food | |
| Kelp and mixed seaweeds | liquid fertilizers, soil amendment Wayne and Wanda! rich in potassium and nitrogen but low in phosphate. Free of terrestrial weeds and fungi. |
|
| Kelps (Kombu) | vegetables in Japan and China Laminaria (kelp – English; kombu – Japan and China) Food. Maybe 75% of their dry bulk is indigestible |
|
| Laminaria digitata in UK and Norway |
alginates | thickening agents (fruit drinks and salad dressing), colloid stabilizers in food (ice creams, sherbets and cheeses), textile, cosmetic, pharmaceutical, paper and welding industries. |
| Laminaria cloustoni (oar weed) | alginates | thickening agents (fruit drinks and salad dressing) colloid stabilizers in food (ice creams, sherbets and cheeses), textile, cosmetic, pharmaceutical, paper and welding industries. |
| Macrocystis pyrifera (kelp – USA) | alginates | thickening agents (fruit drinks and salad dressing) colloid stabilizers in food (ice creams, sherbets and cheeses), textile, cosmetic, pharmaceutical, paper and welding industries. |
| Mastocarpus stellata in British Isles. | agar | |
| Phyllophora nervosa in USSR. | agar | |
| Porphyra (laver – England and USA; luche – Chile; karengo – Maori; nori – Japan; slack – Scotland; sloke – Ireland) |
Food – Maybe 75% of their dry bulk is indigestible. Toasted and used to wrap sushi North Pacific. Cultivated for centuries in Japan, Korea and China |
|
| Pterocladia | agar | |
| Spirulina | food protein – blue-green used for protein food in old (Lake Chad) and new world (Aztecs before conquistadores) |
|
| Ulva | food – eaten as a green vegetable |
|
| Undaria pinnatifida (wakame) | food – Maybe 75% of their dry bulk is indigestible |
