Algae are derived from the Latin word meaning “seaweed”. They are the largest and oldest family of living organisms and are found in all water bodies and also damp places on land. The first plant is known to have been born out of algae. Though Algae lack the basic characteristics of a plant viz., leaves, root, fruit or flower, they however contain the most vital component known as Chlorophyll and can also use it for photosynthesis like plants. And so, in spite of being so close to plant family, Algae has been separately classified as belonging to the Protista family. While plants depend on soil and CO2 to produce sugars, Algae simply thrive on water and sunlight to produce their food.
Algae can vary in sizes from microscopic ones to very large ones that grow in shapes like tubes and trees. These large algae due to their thick root like structure tend to cling onto rocks. Unlike plant bodies which have specialized reproductive structures, Algae tend to reproduce by growing themselves from broken fragments or spores.
Algae has been broadly divided into 4 classes based on their pigmentation by W.H.Harvey, and are known as Red Algae, Brown Algae, Green Algae and Diatomaceae. Algae also combine into symbiotic relationships with other organisms like microorganisms, bacteria, fungi to form symbiotic algae. Some examples of such symbiotic algae are Lichens, Coral Reefs and Sea sponges. In this process the algae provide photosynthates or energy to the host organism which gives protection to the algal cells thereby contributing a mighty effort to maintain aquatic ecology on earth.
The commercial uses of Algae are also multifold. Agar, a gelatinous substance obtained from Algae is used in several ways to benefit mankind. The potential of algae to be used as microscopic power plants is terrific, given the fact that they can produce Hydrogen faster than any other fossil fuels and can do so in a very non-polluting and economical way compared to oil, gas and electricity. Algae are also used as fertilizer, soil conditioner and livestock feed. Thus Algae is also used in pollution control since it efficiently treats sewage than with other added chemicals thereby reducing overall pollution. In agriculture too, enriched algae are proven to be better than commercial fertilizers. The natural pigments present in Algae are used in chemical dyes and coloring agents. A certain kind of red algae is used as a stabilizer in milk products. Apart from all these commercial uses, Algae is also widely known to be the richest nutrition supplement. They are known to provide the body with vitamins A, B1, B2, B6, Niacin, C and iodine, potassium, iron, magnesium , calcium and also are rich in beta-carotene. Algae is also the national food of many countries like China, Japan etc and has emerged in recent times as the richest source of Omega-3 fatty acids. This is used by vegetarians who cannot get the essential DHA and EPA from the usual diet they consume and which are present in oils like cod liver oil, fish oil etc.