Algae, whether red or green, have an important role in the ecosystem of this world. They start out in our oceans, are as food sources to the smallest of creatures who then get eaten by larger and larger creatures exponentially, till their influence gets to the top of the food chain. Where, ironically enough, we eat them. We put them in salads, shampoo and ice cream, and now it's even been found that we could raise algae as a potential new energy source.
THE BASICS OF ALGAE
The term "algae" encompasses a large group, from seaweed to tiny plankton. Real algae are prokaryotes with a single nucleus. They are found in many colors: red, yellow-green, and green. Blue-green algae, or Cyanobacteria, used to be classified as algae but are not any more due to their form.
ALGAE AT WORK IN NATURE
All algae has been used by nature but there are specific kinds people just don't use. These include for instance "red tide" algae - in nature, its role is possibly a cleansing one, from what we can tell. Karena brevis, a kind of Dinoflagellate, is often harmful when it appears, and occasionally is fatal to humans. Here are some other cases where nature is still using what humans have not begun to use:
Coral of coral reefs work together in symbiosis with algae such as Dinoflagellates, to synthesize sugars for energy. The algae also live within sea creatures doing the same task for them: that means that more than half the planet is in a symbiotic relationship with algae.
Algae are very important to animals, because they take in the energy of the sun and convert it to one organic compound or another, which provides food for other creatures. In doing this, they reduce the amount of CO2. Some of them live on the surfaces of sea sponges, protecting them, while others are on land as lichen.
That isn't all, though. Perhaps the one exception to the algae used by nature and that used by humans is plants: Every plant on this planet originally evolved from algae 450 million years ago, specifically the green kind, or "grass-green algae." This means that all the food that herbivores like cows and sheep eat came from algae, and so comes to us when we eat beef or lamb.
HUMANS AND ALGAE
Most of the algae used by humans on the other hand has so far been brown and red algae. For instance, Nori, a Japanese seaweed, has been eaten for hundreds of years. Here are some other ways people have used algae:
People have started using agar, a byproduct of algae. Agar comes from Gelidium amansii, a kind of red algae. The Japanese use it a lot for desserts, but it's also used for paper sizing.
Another important usage for algae is in textiles and paper products, in the form of "alginic acid." This is much less gelatinous than Agar. It's more viscous, and is also used as part of soups and jellies, as well as dehydrated foods.
Red algae from the Irish coast is used to make Carrageenan, which is used in ice cream and shampoo. It's used in Europe to remove protein from drinks.
THE FUTURE OF HUMANS AND ALGAE
The United States Department of Agriculture has been trying out the idea of using algae for fuel since 1950 or so. In 2009, Exxon Mobil partnered up with Craig Venter, who decoded the human genome, to make a more intensive investigation into this popular theory. According to Mr. Venter, using algae for fuel will cut down humans' carbon emissions. An airline reported in early 2009 that they have in fact managed test flights with partial algae fuel.
Margulis, Lynn "Microcosmos"
Margulis, Lynn "Five Kingdoms" pp.78-83, 110-120.
Margulis, Lynn "Symbiotic Planet" p.95, 107-108.