Posted On : 09.02.2016 07:53 pm
Chapter: 11th 12th standard bio zoology Human Body higher secondary school
Economic Importance of Algae - Food, Agriculture, Industry, space travel, Single cell protein, Sewage Disposal
Recent estimates show that nearly half the world's productivity that is carbon fixation, comes from the oceans. This is contributed by the algae, the only vegetation in the sea. Algae are vital as primary producers being at the start of most of aquatic food chains.
Economic Importance of Algae
Recent estimates show that nearly half the world's productivity that is carbon fixation, comes from the oceans. This is contributed by the algae, the only vegetation in the sea. Algae are vital as primary producers being at the start of most of aquatic food chains.
Algae as Food: Algae are important as a source of food for human beings, domestic animals and fishes. Species of Porphyra are eaten in England and USA. Ulva, Laminaria, Sargassum and Chlorella are also used as food in several countries. Sea Japan, weeds(Laminaria, Fucus, Ascophyllum) are used as fodder for domestic animals.
Algae in Agriculture: Various blue green algae such as Oscillatoria, Anabaena, Nostoc, Aulosira increase the soil fertility by fixing the atmospheric nitrogen. In view of the increasing energy demands and rising costs of chemically making nitrogenous fertilizers, much attention is now being given to nitrogen fixing bacteria and blue green algae. Many species of sea weeds are used as fertilizers in China and Japan.
Algae in Industry
Agar - agar : This substance is used as a culture medium while growing bacteria and fungi in the laboratory. It is also used in the preparations of some medicines and cosmetics. It is obtained from the red algae Gelidium and Gracilaria.
A phycocolloid Alginic acid is obtained from brown algae. Algin is used as emulisifier in ice creams, tooth pastes and cosmetics.
Idodine: It is obtained from kelps (brown algae) especially from speicies of Laminaria.
Diatomite : It is a rock-like deposit formed on the siliceous walls of diatoms(algae of Chrysophyceae). When they die they sediment, so that on the seabed and lake bottom extensive deposits can be built up over long periods of time. The resulting 'diatomaceous earth' has a high proportion of silica. Diatomite is used as a fire proof material and also as an absorbent.It is used in sound and fire proof rooms. It is also used in packing of corrosive materials and also in the manufacture of dynamite.
Algae in space travel: Chlorella pyrenoidosa is used in space travel to get rid of Co2 and other body wastes. The algae multiplies rapidly and utilizes the Co2 and liberate 02 during photosynthesis. It decomposes human urine and faeces to get N2 for protein synthesis.
Single cell protein (SCP): Chlorella and Spirullina which are unicellular algae are rich in protein and they are used as protein source. Besides, Chlorella is a source of vitamin also. The rich protein and aminoacid content of chlorella and Spirulina make them ideal for single cell protein production. An antibiotic Chlorellin is extracted from Chlorella.
Sewage Disposal:Algae like Chlorella are grown in large shallow tanks, containing sewage. These algae produce abundant oxygen by rapid photosynthesis. Microorganisms like aerobic bacteria use these oxygen and decompose the organic matter and thus the sewage gets purified.
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11th 12th standard bio zoology Human Body higher secondary school : Economic Importance of Algae - Food, Agriculture, Industry, space travel, Single cell protein, Sewage Disposal |