Kelp - Japanese - [Kombu, Konbu (Japan), dashima (Korea), haidai (China), Laminaria japonica (and several other L. species)]
This is the edible kelp grown along the coasts of Japan, Korea and China. Its long wide fronds are dried and packaged for use particularly to make soup stock but also for use as wrappers for various prepared foods. Almost all this kelp used for food is cultivated rather than gathered wild which explains why there are so few crunchy critters growing on it.

Kelp - Giant - [Macrocystis pyrifera]
Along the temperate western coasts of North and South America, forests of Giant Kelp provide food and shelter for fish, crustaceans and other sea life. The greatest kelp forests in the world are off the coast of California where fronds can grow to 200 feet (60 meters), and in the warm sunlit waters of Southern California can grow more than 10 inches (25 cm) a day.

California kelp is both an important resource and important to the health of the marine environment so harvesting kelp is highly regulated here. The main threat to kelp forests is not harvesting but sea urchins. Order more Uni in your local sushi bar to help the spiny lobsters keep the sea urchin population under control.

Hundreds of tons of giant kelp are harvested every year for production of algin, a thickener and stabilizer used in products from toothpaste to beer to ice cream and to feed farmed abalone.

Wakame - [qundaicai (China), miyeok (Korea), Undaria pinnatifida]
Related to kelp, wakame is a popular seaweed for soups and salads, particularly in Japan, It has a softly crunchy texture and a pleasant slightly spinachy flavor. Most familiar in the U.S. as dry, brittle black tangles in cellophane bags it is also commonly available fresh salted in bags in the refrigerated section of markets serving Oriental communities.

The photo specimens are dried tangle (center), fresh salted tangle briefly soaked (lower right) and a single piece from the fresh tangle spread out (upper left), being a short length cut from one side of the central stem. Fresh salted wakame, soaked for a short time and the salt rinsed off, has a much fresher flavor and crunchier texture than soaked dried and I particularly recommend it for salads.

Wakame has recently been found to contain a substance that stimulates production of a fat burning protein, so expect it to become better known in the West. It has become a troublesome invasive weed along the coasts coasts of non-Oriental countries, so eat up!

Nori - [Laver (Europe), Nori (Japan), kim, gim (Korea), Porphyra yezoensis and P. tenera, sometimes other species]
This algae is farmed intensively in Japan, Korea and China. Once harvested it is shredded and made up into paper-like sheets very much the way handmade paper is made. These sheets are lightly toasted which turns them green. They are used as a wrapping for sushi and as a garnish and as a flavoring in soups.

In Wales similar algae is used to make Laverbread (Bara Lawr) by boiling the seaweed, then mixing it with oatmeal and frying it. In the British Isles it is gathered wild in Wales and Scotland rather than being farmed.

Red Algae is high in protein, iron and iodine as well as containing significant amounts of vitamins B2, A, D and C.

Irish Moss - [Carrageen, Chondrus crispus]
Found along the Atlantic coasts of North America and Europe in the intertidal and subtidal zones, this branching and generally reddish or purplish seaweed grows to about 9 inches long, It can turn green in strong sunlight. Similar species are found and harvested off Korea and Japan.

Irish moss is harvested as a source of carrageenan. This substance is used as a thickener for soups and to make jellies. Industrially it is used as a thickener and and stabilizer in ice cream, luncheon meats and other processed foods and also for fining beer and wine. It has a long history of medicinal use in Europe as well.

Irish moss is always harvested wild, with Canada the major harvester at about 10,000 tons per year followed by France at about 1,260 tons per year.

Sea Lettuce - [Green Laver, Ulva lactuca and other species]
Sea lettuce is found in tidal and near tidal seawater worldwide, generally anchored to rocks or other algae. It is eaten raw in salads and cooked in soups, particularly in Scandinavia, Great Britain, Ireland, China, and Japan.

Sea lettuce is small, generally around 6 inches long but can grow to three feet. It is almost transparently thin and consists of a single frond anchored at one point. It may be ruffled or somewhat divided, generally resembling the lettuce leaves after which it is named.

Most sea lettuce is gathered wild as it grows prolifically wherever there are sufficient nutrients, but some is farmed.

Spirulina - [Arthrospira]
Spirulina is the commercial name for Arthrospira, a Cyanobacteria that forms into spiral threads that can be harvested as pond scum. Spirulina proper is a different bacteria and is not used for food.

This algae was a significant nutrient for the Aztecs and still is for some African tribes, but its commercial potential has been overblown. Wild, unsupportable claims by health food purveyors (A5) have brought heavy fines in California, but the claims continue. Promoters haven't been able to get it accepted as a general food either because it looks bad, tastes bad and is generally heavily contaminated with insects, copeopods and worse - it's pond scum - simple, but not so pure.

Spirulina is promoted to extreme vegetarians as a source of Vitamin B12, which they have a hard time getting from non-animal sources, but any usable B12 in Spirulina more likely comes from insect and copeopod contamination.