Kelp

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Kelp' are included among tha algae. They are very large Eukaryote plants. Kelp are large seaweeds (algae) belonging to the brown algae (class Phaeophyceae) and are classified as the order Laminariales. There are about 300 different genera. Some species can be very long and form kelp forests.

Kelp fisheries is a branch of fisheries science that deals with the study of and uses of large seaweeds of the brown algae group that are commonly called kelp.

Kelp grows in underwater "forests" (kelp forests) in shallow oceans. It requires nutrient-rich water below about 20 °C (68 °F). It is known for its high growth rate — the genera Macrocystis and Nereocystis grow as fast as half a meter a day, ultimately reaching 30 to 80 m.<ref name="Thomas 02">Thomas, D. 2002. Seaweeds. The Natural History Museum, London, p. 15. ISBN 0 565 09175 1</ref>

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.<ref>"Kelp," in Oxford English Dictionary (Second Edition). Oxford University Press, 1989. Retrieved 1 December 2006</ref>

Contents

Morphology

File:BrownGiantKelp3600ppx.jpg
A sample portion of a typical giant kelp thallus.

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 (Mert. & Post & Rupr.)<ref name="Thomas 02" /> and keep the kelp blades close to the surface, holding up the blades by the gas they contain.

Growth and reproduction

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 individual.

Commercial uses

File:Chowiet Island beach kelp.jpg
Alaskan beach kelp
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).<ref name="Clow 52">Clow, Archibald and Clow, Nan L. (1952). Chemical Revolution. Ayer Co Pub, June 1952, pp. 65–90. ISBN 0-8369-1909-2</ref> 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
Citation needed
. 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.

Kombu (Saccharina 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.<ref>Kazuko, Emi: Japanese Cooking, p. 78, Hermes House, 2002, p. 78. ISBN 0-681-32327-2</ref>

Kombu can be used to soften beans during cooking, and to help convert indigestible sugars and thus reduce flatulence.<ref>Graimes, Nicola: The Best-Ever Vegetarian Cookbook, Barnes & Noble Books, 1999, p. 59. ISBN 0-7607-1740-0</ref>

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.<ref>Iodine Helps Kelp Fight Free Radicals and May Aid Humans, Too Newswise, Retrieved on July 8, 2008.</ref>

In 2010 a group of researchers in the University of Newcastle found that a fibrous material called algenate in sea kelp was better at preventing fat absorption than most over-the-counter slimming treatments in laboratory trials. As a food additive it could be maybe used to reduce fat absorption and thus obesity.<ref>Template:Cite web</ref>

As a possible renewable energy source

See also: Biomass energy, Algae fuel

Kelp has a high rate of growth and its decay is quite efficient in yielding methane, as well as sugars that can be converted to ethanol. It has been proposed that large open-ocean kelp farms could serve as a source of renewable energy.<ref>www.biomassmagazine.com/article.jsp?article_id=2166</ref> Unlike some biofuels such as corn ethanol, kelp energy avoids "food vs fuel" issues and does not require irrigation.

Kelp in history and culture

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"<ref>[1] allwords.com definition for "Kelper",</ref><ref>[2] dictionary.com definition for "Kelper"</ref>. The name is primarily applied by outsiders rather than the natives themselves.

Conservation

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.
Citation needed

Gallery

Giant kelp (Macrocystis pyrifera) 01.jpg

Giant kelp in the Monterey Bay Aquarium.

Kelp in Neskowin.jpg

Kelp

Diver1.jpg

Scuba diver in kelp forest

Fish1.jpg

Blue Rockfish in kelp forest

0082 aquaimages.jpg

Anemone and seastar in kelp forest

Kelpforest2500ppx.JPG

An underwater shot of a Kelp forest.

KelpforestI2500ppx.JPG

A Kelp forest.

Kelpforestfish2500ppx.JPG

A fish swimming in a Kelp Forest as seen at the Monterey Bay Aquarium.

Kelpforestupstairsviewmontereybay2500ppx.JPG

A view of the Kelp Forest Exhibit at the Monterey Bay Aquarium from the upstairs level.

Commercial kelp production in China

Laminaria japonica, the important commercial seaweed, was first introduced into China in the late 1920s from Hokkaido, Japan. Commercial production of kelp harvested from its natural habitat took place in Japan for over a century. Yet mariculture of this algae on a very large commercial scale was realized in China only in the 1950s. Between the 1950s and the 1980s kelp production in China increased from about 60 to over 250,000 dry weight metric tons annually, making China the largest producer of Laminaria.

Prominent species

Species of Laminaria in the British Isles;

Species of Laminaria worldwide, listing of species at AlgaeBase:<ref>Laminariales</ref>

Other species in the Laminariales that may be considered as kelp

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:

See also

References

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World Book Online

External links

Template:Commons category Template:Wikispecies

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