Economic importance of algae has been realized in diverse fields as in agriculture, medicine, industry, sewage disposal, formation of petroleum and lime stones, space travel etc. It also causes harm as they causes water bloom, diseases and toxicity in animals.
Beneficial Aspect; Economic Importance of Algae
Importance of Algae in Agriculture
- Blue-green soil algae play a crucial role in agriculture due to their ability to fix nitrogen in the soil. Several significant cyanobacteria found in soil include Tolipothrix tenius, Aulosira fertilissima, Anabaenopsis, Oscillatoria, Anabaena, Nostoc, Spirulina, and Cylindrospermum.
- The nitrogen fixation capability of blue-green algae in rice fields was demonstrated by P. K. De (1939). R. N. Singh (1961) conducted research on using blue-green algae to reclaim Usar lands, stating that by fostering proper cyanobacterial growth, infertile Usar land can be transformed into productive terrain.
- Cyanobacteria also help counteract soil alkalinity and enhance soil fertility.
- Seaweeds are harnessed as biofertilizers. The practice of utilizing large kelps and red algae as manure has been established for centuries, primarily in coastal regions such as France, Ireland, and Sri Lanka.
- Kelps and red algae are rich in potassium but deficient in nitrogen and phosphorus. In these regions, vegetables like potatoes and turnips are directly supplied with seaweeds.
- Seaweeds are sometimes burned, and their ashes are spread over agricultural land, as observed in some countries.
- In certain places, ground forms of Lithothamnion, Lichophyllum, and Chara are used as substitutes for lime in agricultural applications.
Importance of Algae as Food
- Algae engage in the synthesis of organic nutrients and serve as a crucial food source for aquatic animals, including fish.
- Just as land organisms rely on the photosynthetic activities of green leaves, aquatic creatures, either directly or indirectly, depend on algae.
- Various types of algae, such as diatoms, filamentous and some planktonic green algae, as well as several blue-green algae, are frequently found in the digestive tracts of different freshwater and brackish water fish. These algae appear to be directly consumed as nourishment by the fish, establishing algae as a vital resource for pisciculture.
- In the Pacific Islands, many brown, red, and green algae are regular components of human diets.
- Notably, Spirogyra and Oedogonium are significant genera in India, where their dried forms are sold for preparing soups. While Ulva holds importance in Europe.
- In Brazil, Nostoc colonies are utilized as food.
- In the Pacific Islands, young stipes of Laminaria and sporophylls of Alaria are consumed. Ulva lactuca has served as a salad ingredient in Scotland.
- Porphyra, a good source of vitamins B and C, is widely consumed in England, China, Japan, and South Korea.
- Rhodymenia palmata, known as dulse, is also used as food.
- Irish moss (Chondrus crispus), a red alga, has been a well-known and widely used alga in Western Europe for centuries.
- In the Philippines, Caulerpa racemosa is cultivated for food purposes.
- Approximately 25% of the daily diet in China and Japan is estimated to consist of seaweeds.
- Vitamin B is present in Ulva, Enteromorpha, Laminaria, Alaria, Porphyra, Nereocystis, and Chondrus crispus. Ulva, Enteromorpha, Alaria, and Undaria contain Vitamin C.
Importance of Algae as Fooder
- Seaweeds are also utilized as animal fodder. In countries like Norway, France, USA, Denmark, New Zealand, and Scandinavia, seaweeds are commonly used as animal feed.
- Some countries have established small industries to process seaweeds (Ascophyllum, Fucus, Laminaria, etc.) into suitable livestock feed.
- In Scotland and Ireland, Rhodymenia palmata and Alaria esculenta are favored feeds for goats, cows, and sheep.
- Macrocystis, rich in vitamins A and E, is also used. Incorporating dried seaweeds into cattle feed enhances milk yield in cattle.
Importance of Algae in Space Travel
- Chlorella along with Scenedesmus and Synchococcus, serve as nourishment for astronauts during space travel.
- These algae possess high protein content (single-cell protein) and exhibit rapid multiplication.
- Consequently, they efficiently produce a substantial yield of food by utilizing carbon dioxide and releasing ample oxygen as a useful byproduct.
Importance of Algae in Medicine
- Algae have been employed for medicinal purposes since ancient times.
- Historical Chinese writings have documented the utilization of Laminaria sp. to treat goiter. Brown algae, known for their high iodine content, are harnessed in crafting medications for goiter.
- Laminariales members have been used extensively as surgical tools and for facilitating childbirth by expanding the cervix. Chlorellin, an antibiotic, is derived from Chlorella.
- Red algae yield important algal products like agar agar, employed in pharmaceutical industries to manufacture pills and ointments.
- Carrageenin and alginic acid act as agents for blood coagulation.
- Extracts from Digenea, Codium, Alsidium, and Durvillea are effective vermifuges.
- In the Unani medicine system, several algae are utilized to address lung, kidney, and bladder ailments.
- Extracts from Cladophora and Lyngbya exhibit antiviral properties.
Importance of Algae in Formation of Petroleum and Gases
- It is universally recognized that fuels like petroleum and gases find their origins in organic material within the marine environment. Plankton, through photosynthesis, harnessed solar energy and passed it on to marine creatures as nourishment.
- Organic compounds stemming from plankton and these creatures amassed in mud deposits located in the shallower regions of the ocean floor.
- Within these deposits, materials were enveloped through sedimentary processes within an environment devoid of oxygen, gradually transforming into oil and gas.
- The natural gas linked with oil, mainly composed of methane, results from the activities of methane-producing bacteria upon organic compounds.
Importance of Algae in Limestone Formation
- Numerous types of algae draw calcium from both freshwater and saltwater and utilize it to create calcium carbonate, which becomes part of their cell walls.
- The primary contributors to this process are blue-green algae, red algae, and to a lesser extent, dinoflagellates.
- Among them, freshwater blue-green algae are particularly responsible for the creation of expansive limestone deposits near hot springs and glaciers.
- In marine environments, red algae stand out as the key calcareous algae, playing a crucial role in conjunction with cnidarians (small, stationary organisms that contribute to coral reef construction) in the formation of coral reefs.
- Algae not only have a significant impact on limestone formation in oceans and freshwater bodies but have also played a vital role in generating extensive limestone rock formations.
Importance of Algae in Sewage Disposal
- Varieties of Chlamydomonas, Chlorella, Scendesmus, and Euglena are employed within sewage tanks to offer an efficient, swift, and economical approach to transforming sewage into a valuable fertilizer devoid of odor.
- These tanks facilitate the proliferation of algae at the cost of sewage, and these algae engage in photosynthesis, thereby generating oxygen for microorganisms present.
- These microorganisms are responsible for breaking down the organic components of sewage.
Importance of Algae in Industry
- Algae, serving as a wellspring for numerous marketable items, hold substantial value across industries. Algae notably yield essential products such as agar agar, carrageenin, algin, diatomite, and kelp. The industrial application of algae, particularly seaweeds, has been recognized for centuries. These applications encompass:
- Agar-Agar: Agar-agar, a gelatinous substance, is derived from red algae and is stored within their cell walls alongside cellulose. The primary algae species responsible for agar-agar production include Gelidium, Gracilaria, Gigartina, Camphylophora, Eucheuma, Hypnea, Ahnfeltia, and Furcellaria. Agar-agar finds extensive use in microbiology laboratories as a foundation for culturing media for bacteria, fungi, and more. Agar-agar holds significant importance in food preparation, being utilized in items like bread, pastries, cheese, jellies, desserts, and dairy products as an anti-drying agent. Additionally, agar is widely employed in cosmetic, leather, textile, and paper industries.
- Algin– Algin is a carbohydrate, present in the middle lamella and primary walls of brown algae. The primary sources of alginic acid are Ascophyllum, Laminaria, Lessonia, Ecklonia, Macrocystis, Sargassum, Fucus, and Eisenia. Alginates, known for their exceptional water-absorbing properties, are utilized as thickeners in the food industry, cosmetics, and textile industry for printing pastes. Their significance extends to plastic and synthetic fiber production. Algin functions as an emulsifier in confectionery, dental impressions, powders, paints, and ice creams. With its presence in approximately 80% of commercial products, algin finds widespread utilization in various industries, leading to regular harvesting of kelp beds.
- Carrageenin– Carrageenin primarily originates from the red algae Chondrus crispus, commonly known as Irish moss. Additionally, Gigartina is another source of carrageenin. Carrageenin serves as an emulsifying and stabilizing agent across various industries including food, textiles, pharmaceuticals, leather, and brewing. It finds application in toothpaste, deodorants, cosmetics, paints, and is also used as a remedy for cough.
- Diatomite– Diatomite, formed from the siliceous cell walls of deceased diatoms, known as fossil diatoms. These substantial reserves of material, referred to as diatomaceous earth. Diatomaceous earth, possesses high porosity, is insoluble, chemically inert, fire-resistant, and has exceptional absorbent qualities. These properties render it invaluable for applications such as the filtration processes in oil refineries and sugar industries, as well as solvent purification. It also serves as insulation for refrigerators, boilers, and both hot and cold pipes. Additionally, it is used in the construction of structures requiring constant temperature conditions, soundproof spaces, and for packing corrosive chemical liquids and many other applications.
- Kelp– Kelp ash, derived from brown algae, serves as the origin of iodine, soda, and potash. In Japan alone, approximately 100 tons of iodine are produced annually from kelp. The primary genera used for iodine production encompass Laminaria, Fucus, Ecklonia, Ascophyllum, Saccorhiza, and Eisenia.
Harmful Aspect; Economic Importance of Algae
Parasitic Algae
- Parasitic algae cause diseases to economically important plants.
- Red rust of tea (Camellia sinensis) is caused by Cephaleuros virescens. C. coffea is known to cause coffee plants.
Toxic Algae
- Toxic algae are those that induce illness or fatalities among aquatic organisms, particularly animals.
- Certain algae are recognized for emitting harmful or neurotoxic substances, which result in the sickness or demise of aquatic creatures.
- In South Africa, the blue-green algae Microcystis toxica and Anabaena flos-aquae have been responsible for the deaths of thousands of cattle, sheep, and other animals.
- Along the coastlines of California and Washington, Gymnodinium veneficum has been identified as toxic to aquatic animals.
Water Blooms
- During the summer, particularly in the rainy and spring seasons, various types of algae such as green, golden-brown, blue-green, and diatoms experience prolific growth to the extent that ponds, lakes, and reservoirs become hazy and emit fishy odors.
- This abundant growth of algae on the water’s surface is referred to as a water or algal bloom.
- As these blooms proliferate, they lead to water pollution due to an increase in the Biological Oxygen Demand (BOD) level. Consequently, drinking water acquires a fishy smell and an oily taste.
- The reddish color of the Red Sea is a result of seasonal algal blooms composed of cyanophycean algae like Oscillatoria erythraea and Trichodesmium erythraeum.
- Generally, the algae involved in bloom formation are planktonic in nature. These water bloom-forming algae belong to various classes, including Cyanophyceae, Chlorophyceae, Chrysophyceae, Euglenophyceae, and Pyrophyceae.
- Water blooms can manifest in freshwater bodies, lakes, and oceans, and they can either be temporary or persistent. Blooms formed during winter and summer tend to be denser, while those in the rainy season are thinner due to sudden rainfall.
- Key cyanophycean algae responsible for algal blooms encompass Anabaenopsis, Spirulina, Oscillatoria, and Arthrospira.
- Algae like Chlamydomonas, Pandorina, Eudorina, Gonium, Volvox, Cosmarium, and Closterium from the Chlorophyceae class are also known to cause algal blooms.
- Additional algae like Euglena from Euglenophyceae, Synura from Chrysophyceae, and Peridinium, Ceratium, and Gymnodinium from Pyrrophyceae are involved as well.
- While algal blooms can be harmful, as certain algal species produce neurotoxins, blooms consisting of cyanophycean algae can be beneficial nitrogen fixers and are utilized as fertilizers.
- The application of copper sulfate or chlorine can be used to manage algal blooms.
