Difference between revisions of "Kelp" - New World Encyclopedia
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'''Kelp''' is the common name for any of the large [[seaweed]]s comprising the order Laminariales within the [[brown algae]] (class Phaeophyceae). There are about 30 different [[genus|genera]] of kelp, largely found in colder seas along coastlines in the Northern Hemisphere. Some species grow very long and form [[kelp forest]]s. Kelp forests are underwater areas in temperate and polar coastal oceans with a high density of kelp and are recognized as one of the most productive and dynamic [[ecosystem]]s on earth. | '''Kelp''' is the common name for any of the large [[seaweed]]s comprising the order Laminariales within the [[brown algae]] (class Phaeophyceae). There are about 30 different [[genus|genera]] of kelp, largely found in colder seas along coastlines in the Northern Hemisphere. Some species grow very long and form [[kelp forest]]s. Kelp forests are underwater areas in temperate and polar coastal oceans with a high density of kelp and are recognized as one of the most productive and dynamic [[ecosystem]]s on earth. | ||
| − | Kelp is a rich source of [[iodine]] | + | Kelp is a rich source of [[iodine]]. |
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| + | Through the 19th century, the word "kelp" was closely associated with seaweeds that could be burned to obtain [[soda ash]] (primarily sodium carbonate). The seaweeds used included species from both the orders Laminariales and [[Fucales]]. The word "kelp" was also used directly to refer to these processed ashes. | ||
==Overview and description== | ==Overview and description== | ||
| − | Kelp is a type of often large | + | Kelp is a type of [[seaweed]], often large, within the order Laminariales of the brown algae. Seaweeds are macroscopic, multicellular, [[ocean|marine]] [[algae]], which generally are benthic, being anchored to the bottom of the ocean or to solid structures. Brown algae comprise a large group of multicellular, mostly marine algae. Brown algae are placed in the class Phaeophyceae, but their higher level classification is not settled, being variously placed in in the kingdoms Plantae, Protista, Chromista, or Chromalveolata, and in the Divisions Heterokontophyta or Phaeophyta. |
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| − | + | Kelp does have a [[plant]]-like appearance, having tentacle-like roots from which grows a slender stalk with long, [[leaf]]-like blades (Wurges and Frey 2005). In most kelp, the thallus (or body) consists of flat or leaf-like structures known as blades. Blades originate from elongated stem-like structures, the stipes. The holdfast, a root-like structure, anchors the kelp to the substrate of the ocean. Gas-filled bladders ([[pneumatocyst]]s) form at the base of blades of American species, such as ''Nereocystis lueteana'' (Thomas 2002) and keep the kelp blades close to the surface, holding up the leaves by the gas they contain. | |
| − | + | Growth occurs at the base of the [[meristem]], where the blades and stipe meet. Growth may be limited by grazing. [[Sea urchin]]s, for example, can reduce entire areas to [[urchin barrens]]. The kelp life cycle involves a [[ploidy|diploid]] [[sporophyte]] and haploid [[gametophyte]] stage. The haploid phase begins when the mature organism releases many spores, which then germinate to become male or female gametophytes. [[Sexual reproduction]] then results in the beginning of the diploid sporophyte stage which will develop into a mature plant. | |
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| − | + | Kelp grows in underwater "[[forest]]s" (kelp forests) in clear, shallow oceans. It requires nutrient-rich water below about 20°C (68°F). Kelp is known for its high growth rate: the genus ''[[Macrocystis]]'' and ''[[Nereocystis]] luetkeana'' grow as fast as half a [[meter]] a day, ultimately reaching 30 to 80 meters (Thomas 2002). | |
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== Commercial uses == | == Commercial uses == | ||
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* Integrated Taxonomic Information System (ITIS). 2004. [http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=660055 Phaeophyta] ''ITIS Taxonomic Serial No.: 660055''. Retrieved October 13, 2008. | * Integrated Taxonomic Information System (ITIS). 2004. [http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=660055 Phaeophyta] ''ITIS Taxonomic Serial No.: 660055''. Retrieved October 13, 2008. | ||
| + | Thomas, D. 2002. Seaweeds. The Natural History Museum, London, p. 15. ISBN 0 565 09175 1 | ||
| + | .<ref name="Thomas 02">'''Thomas, D.''' 2002. ''Seaweeds.'' The Natural History Museum, London, p. 15. ISBN 0 565 09175 1</ref> | ||
==External links== | ==External links== | ||
Revision as of 21:45, 13 October 2008
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 Californian kelp forest
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Alariaceae |
Kelp is the common name for any of the large seaweeds comprising the order Laminariales within the brown algae (class Phaeophyceae). There are about 30 different genera of kelp, largely found in colder seas along coastlines in the Northern Hemisphere. Some species grow very long and form kelp forests. Kelp forests are underwater areas in temperate and polar coastal oceans with a high density of kelp and are recognized as one of the most productive and dynamic ecosystems on earth.
Kelp is a rich source of iodine.
Through the 19th century, the word "kelp" was closely associated with seaweeds that could be burned to obtain soda ash (primarily sodium carbonate). The seaweeds used included species from both the orders Laminariales and Fucales. The word "kelp" was also used directly to refer to these processed ashes.
Overview and description
Kelp is a type of seaweed, often large, within the order Laminariales of the brown algae. Seaweeds are macroscopic, multicellular, marine algae, which generally are benthic, being anchored to the bottom of the ocean or to solid structures. Brown algae comprise a large group of multicellular, mostly marine algae. Brown algae are placed in the class Phaeophyceae, but their higher level classification is not settled, being variously placed in in the kingdoms Plantae, Protista, Chromista, or Chromalveolata, and in the Divisions Heterokontophyta or Phaeophyta.
Kelp does have a plant-like appearance, having tentacle-like roots from which grows a slender stalk with long, leaf-like blades (Wurges and Frey 2005). In most kelp, the thallus (or body) consists of flat or leaf-like structures known as blades. Blades originate from elongated stem-like structures, the stipes. The holdfast, a root-like structure, anchors the kelp to the substrate of the ocean. Gas-filled bladders (pneumatocysts) form at the base of blades of American species, such as Nereocystis lueteana (Thomas 2002) and keep the kelp blades close to the surface, holding up the leaves by the gas they contain.
Growth occurs at the base of the meristem, where the blades and stipe meet. Growth may be limited by grazing. Sea urchins, for example, can reduce entire areas to urchin barrens. The kelp life cycle involves a diploid sporophyte and haploid gametophyte stage. The haploid phase begins when the mature organism releases many spores, which then germinate to become male or female gametophytes. Sexual reproduction then results in the beginning of the diploid sporophyte stage which will develop into a mature plant.
Kelp grows in underwater "forests" (kelp forests) in clear, shallow oceans. It requires nutrient-rich water below about 20°C (68°F). Kelp is known for its high growth rate: the genus Macrocystis and Nereocystis luetkeana grow as fast as half a meter a day, ultimately reaching 30 to 80 meters (Thomas 2002).
Commercial uses
Bongo kelp ash is rich in iodine and alkali. In great amount, kelp ash can be used in soap and glass production. Until the Leblanc process was commercialized in the early 1800s, burning of kelp in Scotland was one of the principal industrial sources of soda ash (predominantly sodium carbonate).[1] Alginate, a kelp-derived carbohydrate, is used to thicken products such as ice cream, jelly, salad dressing, and toothpaste, as well as an ingredient in exotic dog food and in manufactured goods. Giant kelp can be harvested fairly easily because of its surface canopy and growth habit of staying in deeper water.
Kelp is also used frequently in seaweed fertiliser, especially in the Channel Islands, where it is known as vraic.
Culinary and health
| Kelp (raw) Nutritional value per 100 g | ||||||||||||||||||||||||||||||||||||
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| Energy 40 kcal 180 kJ | ||||||||||||||||||||||||||||||||||||
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| Percentages are relative to US recommendations for adults. Source: USDA Nutrient database | ||||||||||||||||||||||||||||||||||||
Kombu (Laminaria japonica and others), several Pacific species of kelp, is a very important ingredient in Japanese cuisine. Kombu is used to flavor broths and stews (especially dashi), as a savory garnish (tororo konbu) for rice and other dishes, as a vegetable, and a primary ingredient in popular snacks (such as tsukudani). Transparent sheets of kelp (oboro konbu) are used as an edible decorative wrapping for rice and other foods.[2]
Kombu can be used to soften beans during cooking, and to help convert indigestible sugars and thus reduce flatulence.[3]
Because of its high concentration of iodine, brown kelp (Laminaria) has been used to treat goiter, an enlargement of the thyroid gland caused by a lack of iodine, since medieval times.[4]
Kelp in history and culture
Template:Fishery topics During the Highland Clearances, many Scottish Highlanders were moved off their crofts, and went to industries such as fishing and kelping (producing soda ash from the ashes of kelp). At least until the 1820s, when there were steep falls in the price of kelp, landlords wanted to create pools of cheap or virtually free labour, supplied by families subsisting in new crofting townships. Kelp collection and processing was a very profitable way of using this labour, and landlords petitioned successfully for legislation designed to stop emigration. But the economic collapse of the kelp industry in northern Scotland led to further emigration, especially to North America.
Natives of the Falkland Islands are sometimes nicknamed "Kelpers"[5][6]. The name is primarily applied by outsiders rather than the natives themselves.
See the article on seaweed fertiliser.
Endangerment
Overfishing nearshore ecosystems leads to the degradation of kelp forests. Herbivores are released from their usual population regulation, leading to over-grazing of kelp and other algae. This can quickly result in barren landscapes where only a small number of species can thrive.
Giant kelp in the Monterey Bay Aquarium.
Kelp
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Prominent species
- Bull-head kelp, Nereocystis luetkeana, a northwestern American species. Used by coastal indigenous peoples to create fishing nets.
- Giant kelp, Macrocystis pyrifera, the largest seaweed. Found in the Pacific coast of North America and South America.
- Kombu, Laminaria japonica and others, several edible species of kelp found in Japan.
Species of Laminaria in the British Isles
- Laminaria digitata (Hudson) J.V. Lamouroux (Oarweed; Tangle)
- Laminaria hyperborea (Gunnerus) Foslie (Curvie)
- Laminaria ochroleuca Bachelot de la Pylaie
- Laminaria saccharina (Linnaeus) J.V.Lamouroux (sea belt; sugar kelp; sugarwack)
Species of Laminaria world-wide
A comprehensive listing of species in Laminariales and nearly all other algae orders is publicly accessible at http://www.algaebase.org.[7]
- Laminaria agardhii (NE. America)
- Laminaria angustata (Japan)
- Laminaria bongardina Postels et Ruprecht (Bering Sea to California)
- Laminaria cuneifolia (NE. America)
- Laminaria dentigera Klellm. (California - America)
- Laminaria digitata (NE. America)
- Laminaria ephemera Setchell (Sitka, Alaska, to Monterey County, California - America)
- Laminaria farlowii Setchell (Santa Cruz, California, to Baja California - America)
- Laminaria groenlandica (NE. America)
- Laminaria japonica (Japan)
- Laminaria longicruris (NE. America)
- Laminaria nigripes (NE. America)
- Laminaria ontermedia (NE. America)
- Laminaria pallida Greville ex J. Agardh (South Africa)
- Laminaria platymeris (NE. America)
- Laminaria saccharina (Linnaeus) Lamouroux (Aleutian Islands, Alaska to southern California America)
- Laminaria setchellii Silva (Aleutian Islands, Alaska to Baja California America)
- Laminaria sinclairii (Harvey ex Hooker f. ex Harvey) Farlow, Anderson et Eaton (Hope Island, British Columbia to Los Angeles, California - America)
- Laminaria solidungula (NE. America)
- Laminaria stenophylla (NE. America)
Other genera in the Laminariales which may be considered as kelp
- Alaria marginata Post. & Rupr. (Alaska and California - America
- Costaria costata (C.Ag.) Saunders Japan; Alaska, California - America)
- Durvillea antarctica (New Zealand, South America, and Australia)
- Durvillea willana (New Zealand)
- Durvillaea potatorum (Labillardière) Areschoug (Tasmania; Australia)
- Ecklonia brevipes J. Agardh (Australia; New Zealand)
- Ecklonia maxima (Osbeck) Papenfuss (South Africa)
- Ecklonia radiata (C.Agardh) J. Agardh (Australia; Tasmania; New Zealand; South Africa)
- Eisena arborea Aresch. (Vancouver Island, British Columbia, Montrey, Santa Catalina Island, California - America)
- Egregia menziesii (Turn.) Aresch.
- Hedophyllum sessile (C.Ag.) Setch (Alaska, California - America)
- Macrocystis angustifolia Bory (Australia; Tasmania and South Africa)
- Pleurophycus gardneri Setch. & Saund. (Alaska, California - America)
- Pterygophora californica Rupr. (Vancouver Island, British Columbia to Bahia del Ropsario, Baja California and California - America)
Interactions
Some animals are named after the kelp, either because they inhabit the same habitat as kelp or because they feed on kelp. These include:
- Northern kelp crab (Pugettia producta) and graceful kelp crab (Pugettia gracilis), Pacific coast of North America.
- Kelpfish (blenny) (e.g., Heterosticbus rostratus, genus Gibbonsia), Pacific coast of North America.
- Kelp goose (kelp hen) (Chloephaga hybrida), South America and the Falkland Islands
- Kelp pigeon (sheathbill) (Chionis alba and Chionis minor), Antarctic
ReferencesISBN links support NWE through referral fees
- ↑ Clow, Archibald and Clow, Nan L. (1952). Chemical Revolution. Ayer Co Pub, June 1952, pp. 65–90. ISBN 0-8369-1909-2
- ↑ Kazuko, Emi: Japanese Cooking, p. 78, Hermes House, 2002, p. 78. ISBN 0-681-32327-2
- ↑ Graimes, Nicola: The Best-Ever Vegetarian Cookbook, Barnes & Noble Books, 1999, p. 59. ISBN 0-7607-1740-0
- ↑ Iodine Helps Kelp Fight Free Radicals and May Aid Humans, Too Newswise, Retrieved on July 8, 2008.
- ↑ [1]allwords.com definition for "Kelper",
- ↑ [2] dictionary.com definition for "Kelper"
- ↑ Guiry, M.D. & Guiry, G.M. 2006. AlgaeBase version 4.2. World-wide electronic publication, National University of Ireland, Galway. Retrieved 7 December 2006
- Integrated Taxonomic Information System (ITIS). 2004. Phaeophyta ITIS Taxonomic Serial No.: 660055. Retrieved October 13, 2008.
Thomas, D. 2002. Seaweeds. The Natural History Museum, London, p. 15. ISBN 0 565 09175 1
.[1]
External links
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- ↑ Thomas, D. 2002. Seaweeds. The Natural History Museum, London, p. 15. ISBN 0 565 09175 1
