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Indonesia Projected to Become Global Seaweed Producer
Indonesia Projected to Become Global Seaweed Producer
Marine Affairs and Fisheries Minister Fadel Muhammad has the ambition not only to turn Indonesia into a top global fish supplier but also the world’s biggest seaweed producer.
Indonesia is striving to produce 10 million tons of seaweed per by 2015, making it the number one producing country, replacing the Philippines.
“We are trying to increase seaweed production on a mass scale to enable Indonesia to become the biggest seaweed producer in the world,” Minister Fadel Muhammad said when speaking in the Third Seaweed International Business Forum and Exhibition (Seabfex) in Surabaya, East Java, July 2010.
Fadel was optimistic that in the next two years the target might partly be achieved especially in view of the vast seaweed cultivating grounds in Indonesia’s eastern parts, like East Nusa Tenggara (NTT), West Nusa Tenggara (NTB), South Sulawesi, Southeast Sulawesi, Maluku, and North Maluku.
Indonesia, a maritime country having the world’s second longest coastal line, has very big potential in the production of seaweed, which is relatively easy to cultivate as it takes only 45 days to fully grow.
Seaweed is in very high demand in the international markets, especially as a raw material for the production of food, pharmaceuticals and cosmetics. Seaweed is also good fertilizer and is currently under consideration as a potential source of bioethanol.
In line with the planned seaweed production increase, the minister would also want to see many more seaweed processing factories to be built in the country in the next two years in order to boost exports of processed seaweed products. Currently, Indonesia has around 23 seaweed producing companies.
For that purpose, Minister Fadel has urged banking circles to provide smallholder credits for seaweed farmers.
“Without the credits, I think it would be rather difficult to develop seaweed,” he said.
Regarding Indonesia’s plan to mainly process seaweed at home, Prof Dr Jana Anggardiredja, the Technology Assessment and Application Agency (BPPT)’s deputy for natural resource development technology, last March said a lot of researches were needed to raise the target of seaweed processed products from 20 kinds to 50.
Prof Jana, concurrently Chairman of the Indonesian Sea Weed Society, said almost all of the Gracilaria sp seaweed production has been absorbed at home because there has already been a gelatin plant, which is the world`s biggest, in the country.
“In the future we must process it more or, if possible, totally at home,” he said.
He pointed out that China whose sea did not produce seaweeds had many seaweed processing industries and therefore needed a lot of seaweed as the raw materials from Indonesia.
The world`s demand for carrgeenin in 2006 reached 40,000 metric tons a year worth US$335 million, while alginate 12,000 metric tons a year worth US$94 million and gelatine 10,000 metric tons a year worth US$181 million.
By 2014 he hoped absorption of domestically processed carrageenin would increase to 15 percent or around 4,000 tons while exports to reach around 22,000 tons.
He also hoped absorption of domestically processed gelatine would be 85 percent or around 4,250 tons and exports around 750 tons.
In 2009 Indonesia’s seaweed production reached 2,574,000 tons, which increased sharply from the 2005 level of only 910,636 tons.
“Seaweed to the total production of marine and fisheries accounted for 8.9 pct, while we set a target of 27 pct by 2015,” Minister Fadel said last February in the Seabfex III opening which was participated in by representatives from 14 countries, such as the Philippines, South Korea, China, Malaysia, France, India, Germany, Canada, Chile, Japan, Nigeria, Bangladesh, and the Netherlands.
Indonesia’s total seaweed exports reached 102,415.93 tons, worth 124.36 million US dollars, with destinations including Asia, Europe, America, Australia, and Africa.
With regard to carrageenin product, Indonesia had controlled around 13 percent of the world`s market in 2007 and 13.7 percent in 2008, 14 percent in 2009 and predictably 15 percent in 2010, according to Martani Huseini, the marine affairs and fisheries ministry’s director general of fishery product processing and marketing in Gorontalo, Sulawesi, last April.
Petrus Rani Pong, a researcher from the Mamuju fishery and brackish water cultivation research center in South Sulawesi Province, one of the country’s biggest seaweed producers, said in June 2010 that with the support of innovative technology, Indonesia would be able to achieve the 10 million tons target by 2014, from 2.6 million tons in 2010.
Besides, the government has facilitated the expansion of seaweed cultivation areas from 2.1 million hectares into 2.6 million hectares in 2010, he said.
He believed that seaweed cultivation involving thousands of farmers throughout the nation could help improve the people`s welfare since the overseas demands for seaweed were very high.
Of seven seaweed species being cultivated in Indonesia, the majority is Kappaphycus species, which is considered good quality.
Indonesia’s Island of Bali will host the 21st International Seaweed Symposium (ISS) in 2013. The decision was taken in the 20th ISS which was organized in Mexico in February 2010, according to Chairman of the Indonesian Seaweed Producers’ Association (ALRI) Safari Azis Husain.
Azis Husain, who had attended the Mexico meeting, said the appointment of Indonesia to host the important meeting, reflected that Indonesia has been considered of having huge potential in the seaweed cultivation.
Based on the data resulted from a mapping carried out by a Filipino researcher, Dr. Anicia Q. Hurtado, there were 11 spots of the world`s seaweed production centers for E. Cottonii seaweed existing along the Equator, particularly in the Coral Triangle area covering ten ASEAN member nations, Papua New Guinea (PNG) and Pacific islands.
Of the 11 spots, six are in eastern Indonesia, spread from the straits of Makassar, North Sulawesi-Central Sulawesi, East Nusa Tenggara (NTT), Maluku to Papua, according to Azis Husain.
The data showed that the eastern Indonesia area (KTI) in the future is very strategic and detrimental in meeting the global increasing seaweed consumption, he said.
Indonesia is the world`s biggest dried seaweed exporter with its annual exports reaching 145,000 tons, or about 50 percent of the tropical world’s total exports of 290,000 tons.
The total dried seaweed exports of tropical countries which is 290,000 tons accounted for 25 percent of the worl’`s total seaweed exports of 1.2 million tons.
“Beside Indonesia, other tropical countries which export dried seaweed include the Philippines, which contributes 35 percent of the total tropical countries’ exports of dried seaweed,” chairman of Indonesia’s Seaweed Commission, Farid Ma’aruoef, said last April in Padang, West Sumatra.
On a national scale, Indonesia’s wet seaweed production reaches 1,94 million tons, and only 15 percent of it is processed at home.
Seaweed farming in Halmahera, Indonesia
Seaweed farming in Halmahera, Indonesia
In the lagoons of the Goraici region off the island of Halmahera in northern Indonesia, a small village has set aside many acres of shallow protected waters to farm seaweed. Seaweeds have many uses, including food, and are harvested for extracts including alginate, agar and carrageenan – all gelatinous substances which are commercially important as food additives and also used in the pharmaceutical industry.
The farming method is very simple. Local Indonesians set up long monofilmaent lines for the seaweed to grow on. Each line is roughly 50 metres long mounted on sturdy poles at each end. Seedlings are attached to the lines, which are suspended by attaching buoyant plastic bottles at intervals along the line. Navigating between the lanes in their small hand-carved boats, the farmers dive down and collect the seaweed that has fallen off the line and is now resting on the sandy bottom.
Seaweed farming provides a very sustainable source of food and income for these communities and is a viable alternative livelihood for coastal fisherman, who might have otherwise resort to destructive fishing practices such as cyanide or dynamite fishing. There is still some environmental impact however, as many farmers cut down mangrove trees to use as support structures for the lines.
Seaweed Farming in Indonesia: Nusa Lembongan
Seaweed Farming in Indonesia: Nusa Lembongan
Most of the villagers are involved in seaweed farming. It consumes their everyday life, which revolves around the tides and the particular stage of cultivation. The areas used for farming must be relatively shallow and sheltered from the ocean swells. The farming plots look like a giant patchwork quilt as the tide recedes.
The seaweed grown at the island produces carrageenan which is used as an ingredient in food production and cosmetics around the world. Carrageenan is a thickener used in hand lotions and shampoos and interacts with human carotene to give soft skin and silky hair.
During cultivation the offshoots are taken from the parent plant and attached to lines which are anchored to the bottom of the ocean by wooden stakes. The new seedlings are then able to be harvested in approx 4 to 6 weeks.
After harvesting they are laid out to dry, usually for several days, before being sent to market to be sold. The seaweed farmers receive between 600 rupiah and 3,500 rupiah per kilo depending on the type of seaweed and the market value of the day.
Pictures of Seaweed Harvesting
Seaweed uses and utilization
Seaweed uses and utilization
Seaweeds are used in many maritime countries as a source of food, for industrial applications and as a fertiliser. The major utilisation of these plants as food is in Asia, particularly Japan, Korea and China, where seaweed cultivation has become a major industry. In most western countries, food and animal consumption is restricted and there has not been any major pressure to develop seaweed cultivation techniques. This present and potential uses of seaweeds. Industrial utilisation is at present largely confined to extraction for phycocolloids and, to a much lesser extent, certain fine biochemicals. Fermentation and pyrolysis are not been carried out on an industrial scale at present but are possible options for the 21st century.
The present uses of seaweeds at present are as human foods, cosmetics, fertilisers, and for the extraction of industrial gums and chemicals. They have the potential to be used as a source of long- and short-chain chemicals with medicinal and industrial uses. Marine algae may also be used as energy-collectors and potentially useful substances may be extracted by fermentation and pyrolysis. The picture shows some of the many seaweed products or products containing seaweed available today, all of these are made by Irish companies and/or from Irish seaweed.
Rhodophyta: Red Algae - Seaweed
Rhodophyta: Red Algae - Seaweed
Examples: Palmaria, Delesseria, Chondrus, Coralline algae
Characteristics: The red colour of these algae results from the pigments phycoerythrin and phycocyanin; this masks the other pigments, Chlorophyll a (no Chlorophyll b), beta-carotene and a number of unique xanthophylls. The main reserves are typically floridean starch, and floridoside; true starch like that of higher plants and green algae is absent. The walls are made of cellulose and agars and carrageenans, both long-chained polysaccharide in widespread commercial use. There are some unicellular representatives of diverse origin; more complex thalli are built up of filaments.
A very important group of red algae is the coralline algae, which secrete calcium carbonate onto the surface of their cells. Some of these corallines are articulated (right, Corallina, with flexible erect branches; others are crustose (below). These corallines have been used in bone-replacement therapies. Coralline algae were used in ancient times as vermifuges, thus the binomial Corallina officinalis.
Several red algae are eaten: best known amongst these is dulse (Palmaria palmata above) and Carrageen Moss (Chondrus crispus and Mastocarpus stellatus).
However, Nori, popularised by the Japanese is the single most valubable marine crop grown by aquaculture with a value in excess of US$1 billion. More information on aquaculture.
The red algae Kappaphycusand Betaphycus are now the most important sources of carrageenan, a commonly used ingredient in food, particuarly yoghurts, chocolate milk and repared puddings. Gracilaria, Gelidium, Pterocladia and other red algae are used in the manufacture of the all-important agar, used widely as a growth medium for microorganisms and for biotechnological applications.
AlgaeBase dynamic species counts shows that there are about 9,300 species of seaweeds, of which about 6,000 are red algae (Rhodophyta), the vast majority of which are marine. These are found in the intertidal and in the subtidal to depths of up to 40, or occasionally, 250 m. The main biomass of red algae worldwide is provided by the Corallinaceae and Gigartinaceae.
Chlorophyta: Green Algae - Seaweed
Chlorophyta: Green Algae - Seaweed
Examples: Chlorella, Chlamydomonas, Spirogyra, Ulva.
Characteristics: Green colour from chlorophyll a and b in the same proportions as the 'higher' plants; beta-carotene (a yellow pigment); and various characteristic xanthophylls (yellowish or brownish pigments). Food reserves are starch, some fats or oils like higher plants. Green algae are thought to have the progenitors of the higher green plants but there is currently some debate on this point.
Green algae may be unicellular (one cell), multicellular (many cells), colonial (living as a loose aggregation of cells) or coenocytic (composed of one large cell without cross-walls; the cell may be uninucleate or multinucleate). They have membrane-bound chloroplasts and nuclei. Most green are aquatic and are found commonly in freshwater (mainly charophytes) and marine habitats (mostly chlorophytes); some are terrestrial, growing on soil, trees, or rocks (mostly trebouxiophytes). Some are symbiotic with fungi giving lichens. Others are symbiotic with animals, e.g. the freshwater coelentrate Hydra has a symbiotic species of Chlorella as does Paramecium bursaria, a protozoan. A number of freshwater green algae (charophytes, desmids and Spirogyra) are now included in the Charophyta (charophytes), a phylum of predominantly freshwater and terrestrial algae, which are more closely related to the higher plants than the marine green algae belonging to the Chlorophyta (known as chlorophytes). Other green algae from mostly terrestrial habitats are included in the Trebouxiophyceae, a class of green algae with some very unusual features.
Asexual reproduction may be by fission (splitting), budding, fragmentation or by zoospores(motile spores). Sexual reproduction is very common and may be isogamous (gametes both motile and same size); anisogamous (both motile and different sizes - female bigger) or oogamous (female non-motile and egg-like; male motile). Many green algae have an alternation of haploid and diploid phases. The haploid phases form gametangia (sexual reproductive organs) and the diploid phases form zoospores by reduction division (meiosis). Some do not have an alternation of generations, meiosis occurring in the zygote.
Life was indeed very simple when all green-coloured algae were included in a single class, the Chlrophyceae. Increasingly, it has become clear that the green algae are very diverse in their relationships and are now included in two phyla (Chlrophyta and Charophyta) and at least 17 classes! Progress has been so rapid that text-books are out of date almost as soon as they are printed. Up-to-date numbers for each of these classes and their relationships with the Rhodophyta are given by AlgaeBase.
AlgaeBase dynamic species counts shows that there are about 4,500 species of Chlorophyta including about 550 species of Trebouxiophyceae (mostly subaerial and freshwater), 2,500 Chlorophyceae (mostly freshwater), 800 species of Bryopsidophyceae (seaweeds), 50 species of Dasycladophyceae (seaweeds), 400 Siphoncladophyceae (seaweeds), and 250 marine Ulvophyceae (seaweeds). The Charophyta is entirely freshwater and includes 3,500 species currently allocated to 5 classes.
Commercial uses: Organic beta-carotene is produced in Australia from the hypersaline (growing in high salinity water often known as brine) green alga Dunaliella salina grown in huge ponds. Carotene has been shown to be very effective in preventing some cancers, including lung cancer. Caulerpa, a marine tropical to warm-temperate genus, is very popular in aquaria. Unfortunately, this has led to the introduction of a number of Caulerpa species around the world, the best-known example being the invasive species Caulerpa taxifolia.
Chlorella, a genus of freshwater and terrestrial unicellular green alga with about 100 species, is grown like yeast in bioreactors, where it has a very rapid life history. It may be taken in the form of tablets or capsules, or added to foods such as pasta or cookies. Taken in any form, it is said improve the nutritional quality of a daily diet.
Phaeophyceae: Brown Algae - Seaweed
Phaeophyceae: Brown Algae - Seaweed
Examples of brown seaweeds are : Laminaria and Saccharina, Fucus, Sargassum muticum
Characteristics
The brown colour of these algae results from the dominance of the xanthophyll pigment fucoxanthin, which masks the other pigments, Chlorophyll a and c (there is no Chlorophyll b), beta-carotene and other xanthophylls. Food reserves are typically complex polysaccharides, sugars and higher alcohols. The principal carbohydrate reserve is laminaran, and true starch is absent (compare with the green algae). The walls are made of cellulose and alginic acid, a long-chained heteropolysaccharide.
There are no known unicellular or colonial representatives; the simplest plant form is a branched, filamentous thallus. The kelps are the largest (up to 70 m long) and perhaps the most complex brown algae, and they are the only algae known to have internal tissue differentiation into conducting tissue; there is, however, no true xylem tissue as found in the 'higher' plants.
Most brown algae have an alternation of haploid and diploid generations. The haploid thalli form isogamous, anisogamous or oogamous gametes and the diploid thalli form zoospores, generally by meiosis. The haploid (gametangial) and diploid (sporangial) thalli may be similar (isomorphic) or different (heteromorphic) in appearance, or the gametangial generation may be extremely reduced (Fucales). The brown Giant Kelp Macrocystis pyrifera (top) is harvested off the coasts of California for feeding abalone. It used to be used for alginate extraction, but this now mostly comes from Atlantic Ascophyllum nodosum and Laminaria hyperborea. Alginates, derivatives of alginic acids, are used commercially for toothpastes, soaps, ice cream, tinned meats, fabric printing, and a host of other applications. It forms a stable viscous gel in water, and its primary function in the above applications is as a binder, stabilizer, emulsifier, or moulding agent. Saccharina japonica, formerly Laminaria, and other species of the genus are grown on ropes in China, Korea and Japan for food and alginate production. Undaria pinnatifida is also cultivated in Japan, Korea and China for production of Wakame, a valuable food kelp. Small amounts are also grown in Atlantic France for the European market.
About 16,000 tonnes of Ascophyllum nodosum (above, Feamainn bhuí in Irish, referring to the yellow colour in summer) are harvested each year in Ireland, dried and milled in factories at Arramara Teo., Cill Chiaráin (Kilkerrin), Co. Galway; and some 3,000 t of the resulting seaweed meal is exported and processed in Scotland for the production of alginic acid. Laminaria hyperborea stipes (sea rods) are harvested in Norway and used to be collected in drift in Scotland and Ireland. The rods are used for the manufacture of high-grade alginates. Other brown algae are used for the extraction of agricultural sprays ('liquid seaweed extracts'). These extracts are used at low concentrations on crops and their hormone-like activities are thought to be due to betaines, cytokinenins, etc. In some areas, like the west of Ireland and Scotland, kelps and other brown algae are gathered as a fertiliser for land
Common Edible Seaweeds
Common Edible Seaweeds
Common edible seaweeds include the following:
- Arame (Eisenia bicyclis)
- Badderlocks (Alaria esculenta)
- Bladderwrack (Fucus vesiculosus)
- Carola (Callophyllis variegata)
- Carrageen moss (Mastocarpus stellatus)
- Channelled wrack (Pelvetia canaliculata)
- Chlorella
- Cochayuyo (Durvillaea antarctica)
- Dulse (Palmaria palmata)
- Euchema cottonii
- Gutweed (Enteromorpha intestinalis)
- Hijiki or Hiziki (Sargassum fusiforme)
- Irish moss (Chondrus crispus)
- Laver (Porphyra laciniata/Porphyra umbilicalis)
- Limu Kala (Sargassum echinocarpum)
- Kombu (Saccharina japonica)
- Mozuku (Cladosiphon okamuranus)
- Nori (various species of the red alga Porphyra)
- Oarweed (Laminaria digitata)
- Ogonori (Gracilaria)
- Sugar kelp (Saccharina latissima)
- Sea Grapes or green caviar (Caulerpa lentillifera)
- Sea Lettuce (various species of the genus Ulva)
- Spiral wrack (Fucus spiralis)
- Spirulina (Arthrospira platensis and Arthrospira maxima)
- Thongweed (Himanthalia elongata)
- Wakame (Undaria pinnatifida)
Seaweed Nutrition and Uses
Seaweed Nutrition and Uses
Seaweed contains high levels of iodine relative to other foods. In the Philippines, Tiwi, Albay residents discovered a new pancit or noodles made from seaweed, which can be cooked into pancit canton, pancit luglug, spaghetti or carbonara and is claimed to have health benefits such as being rich in calcium, magnesium and iodine.
Polysaccharides in seaweed may be metabolized in humans through the action of bacterial gut enzymes. Research has failed to find such enzymes in North-American population, while being frequent in Japanese population.
In some parts of Asia, nori 海苔 (in Japan), zicai 紫菜 (in China), and gim 김 (in Korea), sheets of the dried red alga Porphyra are used in soups or to wrap sushi or onigiri. Chondrus crispus (commonly known as Irish moss) is another red alga used in producing various food additives, along with Kappaphycus and various gigartinoid seaweeds.
Japan consumes seven types of seaweed identified by name, and the general term for seaweed is used primarily for science and not in menus.
Edible seaweed
Edible seaweed
Edible seaweed are algae that can be eaten and used in the preparation of food. It typically contains high amounts of fiber and, contrary to land based plant foods, they contain a complete protein. They may belong to one of several groups of multicellular algae: the red algae, green algae, and brown algae.
Seaweeds are also harvested or cultivated for the extraction of alginate, agar and carrageenan, gelatinous substances collectively known as hydrocolloids or phycocolloids. Hydrocolloids have attained commercial significance, especially in food production as food additives. The food industry exploits the gelling, water-retention, emulsifying and other physical properties of these hydrocolloids.
Most edible seaweeds are marine algae as most freshwater algae are toxic. While marine algae are not toxic, some do contain acids that irritate the digestion canal, while some others can have a laxative and electrolyte balancing effect.
Seaweed Farming Culture methods
Seaweed Farming Culture methods
The earliest seaweed farming guides in the Philippines recommended cultivation of Laminaria seaweed and reef flats at approximately 1m depth at low tide . They also recommended cutting off sea grasses and removing sea urchins prior to farm construction. Seedlings are then tied to monofilament lines and strung between mangrove stakes pounded into the substrate. This off-bottom method is still one of the major methods used today.
There are new long line cultivation methods that can be used in deeper water approximately 7 m in depth. They use floating cultivation lines anchored to the bottom and are the primary methods used in the villages of North Sulawesi, Indonesia.
Cultivation of seaweed in Asia is a relatively low-technology business with a high labour requirement. There have been many attempts in various countries to introduce high technology to cultivate detached plants growth in tanks on land in order to reduce labour, but they have yet to attain commercial viability.
Seaweed farming
Seaweed farming
Seaweed farming is the practice of cultivating and harvesting seaweed. In its simplest form, it consists of the management of naturally found batches. In its most advanced form, it consists of fully controlling the life cycle of the algae. The main food species grown by aquaculture in Japan, China and Korea include Gelidium, Pterocladia, Porphyra, and Laminaria. Seaweed farming has frequently been developed as an alternative to improve economic conditions and to reduce fishing pressure and over exploited fisheries. Seaweeds have been harvested throughout the world as a food source as well as an export commodity for production of agar and carrageenan products.
Other uses of Seaweed
Other uses of Seaweed
Other seaweeds may be used as fertilizer, compost for landscaping, or a means of combating beach erosion through burial in beach dunes. Seaweed is currently under consideration as a potential source of bioethanol. Seaweed is an ingredient in toothpaste, cosmetics and paints.
Alginates enjoy many of the same uses as carrageenan, and are used in industrial products such as paper coatings, adhesives, dyes, gels, explosives and in processes such as paper sizing, textile printing, hydro-mulching and drilling.
Uses of Seaweed for Herbalism
Uses of Seaweed for Herbalism
Alginates are used in wound dressings, and production of dental moulds. In microbiology research, agar - a plant-based goo similar to gelatin and made from seaweed - is extensively used as culture medium. Carrageenans, alginates and agaroses (the latter are prepared from agar by purification), together with other lesser-known macroalgal polysaccharides, also have several important biological activities or applications in biomedicine.
Seaweed is a source of iodine, necessary for thyroid function and to prevent goitre. However, an excess of iodine is suspected in the heightened cancer risk in Japanese who consume a lot of the plant, and even bigger risks in post-menopausal women.
Seaweeds may have curative properties for tuberculosis, arthritis, colds and influenza, worm infestations and even tumors. In Japan, seaweed eaten as nori is known as a remedy for radiation poisoning.
Seaweed extract is used in some diet pills. Other seaweed pills exploit the same effect as gastric banding, expanding in the stomach to make the body feel more full.
Uses of Seaweed as Food
Uses of Seaweed as Food
Seaweeds are consumed by coastal people, particularly in East Asia, e.g., Brunei, Japan, China, Korea, Taiwan, Singapore, Thailand, Cambodia, and Vietnam, but also in South Africa, Indonesia, Malaysia, Belize, Peru, Chile, the Canadian Maritimes, Scandinavia, South West England,[6] Ireland, Wales, California, Philippines, and Scotland.
In Asia, Nori (海苔, Japan), Zicai (紫菜, China), and Gim (김, Korea) are sheets of dried Porphyra used in soups or to wrap sushi. Chondrus crispus (commonly known as Irish Moss or carrageenan moss) is another red alga used in producing various food additives, along with Kappaphycus and various gigartinoid seaweeds. Porphyra is a red alga used in Wales to make laver. Laverbread, made from oats and the laver, is a popular dish there. In northern Belize, edible seaweeds are mixed with milk, nutmeg, cinnamon, and vanilla to make a common beverage affectionately called "Dulce" (or "sweet").
Seaweeds are also harvested or cultivated for the extraction of alginate, agar and carrageenan, gelatinous substances collectively known as hydrocolloids or phycocolloids. Hydrocolloids have attained commercial significance as food additives.[7] The food industry exploits their gelling, water-retention, emulsifying and other physical properties. Agar is used in foods such as confectionery, meat and poultry products, desserts and beverages and moulded foods. Carrageenan is used in salad dressings and sauces, dietetic foods, and as a preservative in meat and fish products, dairy items and baked goods.
ECOLOGY OF SEAWEED
ECOLOGY OF SEAWEED
Two specific environmental requirements dominate seaweed ecology. These are the presence of seawater (or at least brackish water) and the presence of light sufficient to drive photosynthesis. Another common requirement is a firm attachment point. As a result, seaweeds most commonly inhabit the littoral zone and within that zone more frequently on rocky shores than on sand or shingle. Seaweeds occupy a wide range of ecological niches. The highest elevation is only wetted by the tops of sea spray, the lowest is several meters deep. In some areas, littoral seaweeds can extend several miles out to sea. The limiting factor in such cases is sunlight availability. The deepest living seaweeds are some species of red algae.
A number of species such as Sargassum have adapted to a fully planktonic niche and are free-floating, depending on gas-filled sacs to maintain an acceptable depth.
Others have adapted to live in tidal rock pools. In this habitat seaweeds must withstand rapidly changing temperature and salinity and even occasional drying.
Seaweed
A seaweed may belong to one of several groups of multicellular algae: the red algae, green algae, and brown algae. As these three groups are not thought to have a common multicellular ancestor, the seaweeds are a polyphyletic group. In addition, some tuft-forming bluegreen algae (Cyanobacteria) are sometimes considered as seaweeds — "seaweed" is a colloquial term and lacks a formal definition.
Structure of Seaweed
- Seaweeds' appearance somewhat resembles non-arboreal terrestrial plants.
- thallus: the algal body
- lamina: a flattened structure that is somewhat leaf-like
- sorus: spore cluster
- on Fucus, air bladders: float-assist organ (on blade)
- on kelp, floats: float-assist organ (between lamina and stipe)
- stipe: a stem-like structure, may be absent
- holdfast: specialized basal structure providing attachment to a surface, often a rock or another alga.
- haptera: finger-like extensions of holdfast anchoring to benthic substrate
- The stipe and blade are collectively known as the frond.
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