The Full Wiki

Seaweed: Wikis

  
  
  
  

Note: Many of our articles have direct quotes from sources you can cite, within the Wikipedia article! This article doesn't yet, but we're working on it! See more info or our list of citable articles.

Did you know ...


More interesting facts on Seaweed

Include this on your site/blog:

Encyclopedia

From Wikipedia, the free encyclopedia

Photo of seaweed with small swollen areas at the end of each frond
Ascophyllum nodosum exposed to the sun in Nova Scotia, Canada
Photo of detached seaweed frond lying on sand
Dead Man's Fingers (Codium fragile) off Massachusetts coast in the United States
Photo of seaweed with the tip floating at the surface
The top of a kelp forest in Otago, New Zealand

Seaweed is a loose colloquial term encompassing macroscopic, multicellular, benthic marine algae.[1] The term includes some members of the red, brown and green algae. Seaweeds can also be classified by use (as food, medicine, fertilizer, industrial, etc.).

Contents

Taxonomy

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 paraphyletic 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

Seaweeds' appearance somewhat resembles non-arboreal terrestrial plants.

  • thallus: the algal body
    • lamina: a flattened structure that is somewhat leaf-like
    • 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.

Ecology

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 the various kelps.

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 niche seaweeds must withstand rapidly changing temperature and salinity and even occasional drying.[2]

Uses

Seaweed farming in Bali, Indonesia
Photo of near-shore ocean, divided into rectangles, most containing a yards-long, narrow boat
Small plots being used to farm seaweed in Indonesia, with each rectangle belonging to a different family

Seaweed has a variety of purposes, for which it is farmed[3] or foraged from the wild.[4]

Food

Photo of plastic food package
Packaged nori

Seaweeds are consumed by coastal people, particularly in East Asia, e.g., Japan, China, Korea, Taiwan, Thailand, and Vietnam, but also in Indonesia, Belize, Peru, Chile the Canadian Maritimes, Scandinavia, Ireland, Wales, Philippines, and Scotland. Tiwi, Albay residents discovered a new pancit or noodles made from seaweed, which has health benefits. It is rich in calcium and magnesium and seaweed noodles can be cooked into pancit canton, pancit luglug, spaghetti or carbonara.[5]

In Asia, Zicai (紫菜) (in China), gim (in Korea) and nori (in Japan) 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. Affectionately called "Dulce" in northern Belize, seaweeds are mixed with milk, nutmeg, cinnamon, and vanilla to make a common beverage.

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.[6] 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.

Warning: Sea vegetables are naturally rich in iodine. Excess iodine intake may affect thyroid function. It is recommended that no more than 1g of dried sea vegetable be consumed per week, for adults. Children under 4 years of age should have no more than a third of this.

Medicine

Photo of rocks covered by dried plant matter
Seaweed-covered rocks in the United Kingdom

Alginates are used in wound dressings, and production of dental moulds. In microbiology research, agar is extensively used as culture medium.[citation needed]

Seaweed is a source of iodine,[7] necessary for thyroid function and to prevent goitre.

Seaweeds may have curative properties for tuberculosis, arthritis, colds and influenza, worm infestations and even tumors.[1]

Seaweed extract is used in some diet pills.[8][9][10] Other seaweed pills exploit the same effect as gastric banding, expanding in the stomach to make the body feel more full.[11][12]

Other uses

Other seaweeds may be used as fertilizer.[citation needed] Seaweed is currently under consideration as a potential source of bioethanol.[13][14] Seaweed is an ingredient in toothpaste, cosmetics and paints.[3]

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.

See also

Claudea elegans tetrasporangia
Seaweed genera

References

  1. ^ Smith, G.M. 1944. Marine Algae of the Monterey Peninsula, California. Stanford Univ., 2nd Edition.
  2. ^ Lewis, J.R. 1964. The Ecology of Rocky Shores. The English Universities Press Ltd.
  3. ^ a b "Seaweed farmers get better prices if united". Sun.Star. 2008-06-19. http://www.sunstar.com.ph/static/dav/2008/06/19/bus/seaweed.farmers.get.better.prices.if.united.jica.html. Retrieved 2008-07-16. 
  4. ^ "Springtime's foraging treats". Life and Health, Guardian.co.uk. The Guardian. 2007-01-06. http://lifeandhealth.guardian.co.uk/guides/freestuff/story/0,,1981372,00.html. Retrieved 2008-07-16. 
  5. ^ "Albay folk promote seaweed ‘pansit’". ABS-CBN Regional Network Group. 2008-04-08. http://www.abs-cbnnews.com/nation/regions/04/08/08/albay-folk-promote-seaweed-pansit. Retrieved 2009-08-04. 
  6. ^ Round F.E. 1962 The Biology of the Algae. Edward Arnold Ltd.
  7. ^ Iodine in Seaweed
  8. ^ http://www.timesonline.co.uk/tol/life_and_style/food_and_drink/article2472720.ece
  9. ^ Maeda, H; Hosokawa, M; Sashima, T; Funayama, K; Miyashita, K (Jul 2005). "Fucoxanthin from edible seaweed, Undaria pinnatifida, shows antiobesity effect through UCP1 expression in white adipose tissues". Biochemical and biophysical research communications 332 (2): 392–7. doi:10.1016/j.bbrc.2005.05.002. PMID 15896707. 
  10. ^ http://www.dailymail.co.uk/health/article-1134430/So-diet-pills-CAN-trim-tum-Our-expert-brands-test.html?ITO=1490
  11. ^ http://www.foxnews.com/story/0,2933,476766,00.html?sPage=fnc/health/nutrition
  12. ^ http://news.softpedia.com/news/Appesat-the-Seaweed-Diet-Pill-that-Expands-in-the-Stomach-101227.shtml
  13. ^ Ireland Taps New Energy Source : Discovery News : Discovery Channel
  14. ^ Seaweed Biofuels: Production of Biogas and Bioethanol from Brown Macroalgae

External links

  • Michael Guiry's Seaweed Site, information on all aspects of algae, seaweeds and marine algal biology
  • AlgaeBase, a searchable taxonomic, image, and utilization database of freshwater, marine and terrestrial algae, including seaweed.
  • SeaweedAfrica, information on seaweed utilisation for the African continent.
  • Seaweed Malaysia Site, information on seaweed nutrition, facts and information for human health.

Source material

Up to date as of January 22, 2010

From Wikisource

Seaweed
by Henry Wadsworth Longfellow
From The Seaside and the Fireside.

When descends on the Atlantic
The gigantic
Storm-wind of the equinox,
Landward in his wrath he scourges
The toiling surges,
Laden with seaweed from the rocks:

From Bermuda's reefs; from edges
Of sunken ledges,
In some far-off, bright Azore;
From Bahama, and the dashing,
Silver-flashing
Surges of San Salvador;

From the tumbling surf, that buries
The Orkneyan skerries,
Answering the hoarse Hebrides;
And from wrecks of ships, and drifting
Spars, uplifting
On the desolate, rainy seas;--

Ever drifting, drifting, drifting
On the shifting
Currents of the restless main;
Till in sheltered coves, and reaches
Of sandy beaches,
All have found repose again.

So when storms of wild emotion
Strike the ocean
Of the poet's soul, erelong
From each cave and rocky fastness,
In its vastness,
Floats some fragment of a song:

Front the far-off isles enchanted,
Heaven has planted
With the golden fruit of Truth;
From the flashing surf, whose vision
Gleams Elysian
In the tropic clime of Youth;

From the strong Will, and the Endeavor
That forever
Wrestle with the tides of Fate
From the wreck of Hopes far-scattered,
Tempest-shattered,
Floating waste and desolate;--

Ever drifting, drifting, drifting
On the shifting
Currents of the restless heart;
Till at length in books recorded,
They, like hoarded
Household words, no more depart.


Simple English

coast in the United States|alt=Photo of detached seaweed frond lying on sand]]
in Otago, New Zealand|alt=Photo of seaweed with the tip floating at the surface]]

Seaweed is a term used for several forms of multicellular marine algae. Red algae, Green algae and Brown algae are commonly considered to be seaweed. Seaweed gets its energy from photosynthesis. Because it looks very different from other plants, seaweed is usually not considered to be a plant.

Contents

Ecology

Two specific environmental requirements dominate seaweed ecology. These are the presence of seawater (or at least brackish water) and the presence of enough light for photosynthesis. Often, a firm attachment point is also needed.

For this reason, seaweeds can be found in the littoral zone of the sea. Within that zone, they are more frequent on a rocky shore, than on sand.

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 the various kelps.

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 niche seaweeds must withstand rapidly changing temperature and salinity and even occasional drying.[1]

Uses

Seaweed has different uses. Sometimes it is farmed[2] or foraged from the wild.[3]

Food

|alt=Photo of plastic food package]] People living on the coast often eat seaweed, especially those in East Asia, such as Japan, China, Korea, Taiwan, Thailand, and Vietnam. It is also used in Belize, Peru, the Canadian Maritimes, Scandinavia, Ireland, Wales, Philippines, and Scotland.

Tiwi, Albay residents discovered a new pancit or noodles made from seaweed. These have health benefits. Seaweed is rich in calcium and magnesium and seaweed noodles can be cooked into pancit canton, pancit luglug, spaghetti or carbonara.[4]

In Asia, Zicai (紫菜) (in China), gim (in Korea) and nori (in Japan) 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. Affectionately called "Dulce" in northern Belize, seaweeds are mixed with milk, nutmeg, cinnamon, and vanilla to make a common beverage.

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.[5] 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.

Medicine

|alt=Photo of rocks covered by dried plant matter]]

Seaweed is a source of iodine,[6] necessary for thyroid function and to prevent goitre.

Seaweed extract is used in some diet pills.[7][8][9] Other seaweed pills exploit the same effect as gastric banding, expanding in the stomach to make the body feel more full.[10][11]

Other uses

Seaweed is currently under consideration as a potential source of bioethanol.[12][13] Seaweed is an ingredient in some toothpaste, cosmetics and paints.[2]

References

  1. Lewis, J.R. 1964. The Ecology of Rocky Shores. The English Universities Press Ltd.
  2. 2.0 2.1 "Seaweed farmers get better prices if united". Sun.Star. 2008-06-19. http://www.sunstar.com.ph/static/dav/2008/06/19/bus/seaweed.farmers.get.better.prices.if.united.jica.html. Retrieved 2008-07-16. 
  3. "Springtime's foraging treats". Life and Health, Guardian.co.uk. The Guardian. 2007-01-06. http://lifeandhealth.guardian.co.uk/guides/freestuff/story/0,,1981372,00.html. Retrieved 2008-07-16. 
  4. "Albay folk promote seaweed ‘pansit’". ABS-CBN Regional Network Group. 2008-04-08. http://www.abs-cbnnews.com/nation/regions/04/08/08/albay-folk-promote-seaweed-pansit. Retrieved 2009-08-04. 
  5. Round F.E. 1962 The Biology of the Algae. Edward Arnold Ltd.
  6. Iodine in Seaweed
  7. http://www.timesonline.co.uk/tol/life_and_style/food_and_drink/article2472720.ece
  8. Maeda, H; Hosokawa, M; Sashima, T; Funayama, K; Miyashita, K (Jul 2005). [Expression error: Unexpected < operator "Fucoxanthin from edible seaweed, Undaria pinnatifida, shows antiobesity effect through UCP1 expression in white adipose tissues"]. Biochemical and biophysical research communications 332 (2): 392–7. doi:10.1016/j.bbrc.2005.05.002. PMID 15896707. 
  9. http://www.dailymail.co.uk/health/article-1134430/So-diet-pills-CAN-trim-tum-Our-expert-brands-test.html?ITO=1490
  10. http://www.foxnews.com/story/0,2933,476766,00.html?sPage=fnc/health/nutrition
  11. http://news.softpedia.com/news/Appesat-the-Seaweed-Diet-Pill-that-Expands-in-the-Stomach-101227.shtml
  12. Ireland Taps New Energy Source : Discovery News : Discovery Channel
  13. Seaweed Biofuels: Production of Biogas and Bioethanol from Brown Macroalgae









Got something to say? Make a comment.
Your name
Your email address
Message