Seaweed 46221 226162357 2008-07-17T02:46:05Z Kingdon 668610 revert vandalism/test: [[WP:UNDO|Undid]] revision 226026291 by [[Special:Contributions/88.104.152.8|88.104.152.8]] ([[User talk:88.104.152.8|talk]]) {{pp-move-vandalism|small=yes}} {{paraphyletic group | color = #e0d0b0 |image=Asco-nado.jpg |image_caption=''[[Ascophyllum nodosum]]'' exposed to the sun in [[Nova Scotia]], [[Canada]] |domain=[[Eukarya]] |included= Some members of: *[[Rhodophyta]] *[[Phycophyta]] *[[Chlorophyta]] *[[Charophyta]] }} [[Image:codiumfragile.jpg|thumb|Dead Man's Fingers (''Codium fragile'') off [[Massachusetts]] coast]] [[Image:Kelp forest Otago 1s.JPG|right|thumb|The top of a [[kelp forest]] in [[Otago]], [[New Zealand]] ]] {{otheruses}} '''Seaweed''' is a loose colloquial term encompassing macroscopic, [[multicellular]], [[benthos|benthic]] [[ocean|marine]] [[algae]].<ref> Smith, G.M. 1944. ''Marine Algae of the Monterey Peninsula, California''. Stanford Univ., 2nd Edition.</ref> The term includes some members of the [[rhodophyta|red]], [[phycophyta|brown]] and [[green alga]]e. == Taxonomy == A seaweed may belong to one of several groups of multicellular [[algae]]: the [[red alga]]e, [[green alga]]e, and [[brown alga]]e. As these three groups are not thought to have a common multicellular ancestor, the seaweeds are a [[paraphyly|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 [[plant]]s. * [[Thallus (tissue)|thallus]]: the algal body ** [[lamina (algae)|lamina]]: a flattened structure that is somewhat leaf-like *** [[sorus]]: [[spore]] cluster *** on ''[[Fucus]]'', air bladders: [[Pneumatocyst|float]]-assist organ (on blade) *** on [[kelp]], [[Pneumatocyst|float]]s: float-assist organ (between lamina and stipe) ** [[stipe (botany)|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 [[frond]]s. ==Ecology== The ecology of seaweeds is dominated by two specific environmental requirements. These are the presence of sea-water (or at least [[brackish water]]) and the presence of light sufficient to drive [[photosynthesis]]. A very common requirement is also to have a firm point of attachment. As a result, seaweeds are most commonly found in the [[littoral]] zone and within that zone more frequently on rocky shores than on sand or shingle. The ecological niches utilised by seaweeds are wide ranging. At the highest level are those that inhabit the zone that is only wetted by the tops of sea spray, the deepest living are those that are attached to the sea-bed under several meters of water. In some parts of the world, the area colonized by littoral seaweeds can extend for several miles away from the shore. The limiting factor in such cases is the availability of sufficient sun-light to support photosynthesis. The deepest living sea-weeds are the various [[kelp]]s. In addition to the familiar sea-shore seaweeds, a number of species have adapted to a fully planktonic niche and are free-floating, often with the assistance of gas filled sacs. ''[[Sargassum]]'' is one of the better known examples of this type of seaweed. A number of species have adapted to the specialised environment of tidal rock pools. In this niche seaweeds are able to withstand rapidly changing temperature and salinity and even occasional drying. <ref>Lewis, J.R. 1964. ''The Ecology of Rocky Shores.'' The English Universities Press Ltd.</ref> == Uses == [[Image:Seaweed Farms in Indonesia.jpg|thumb|left|Small plots being used to farm seaweed in [[Indonesia]], with each square belonging to a different family.]] Seaweed has a variety of purposes, for which it is [[agriculture|farmed]],<ref name="Sun.Star">{{cite news |title= Seaweed farmers get better prices if united|url= http://www.sunstar.com.ph/static/dav/2008/06/19/bus/seaweed.farmers.get.better.prices.if.united.jica.html |publisher= ''[[Sun.Star]]''|date= [[2008]]-[[06-19]]|accessdate=2008-07-16 }}</ref> or foraged from the wild.<ref>{{cite web |url= http://lifeandhealth.guardian.co.uk/guides/freestuff/story/0,,1981372,00.html|title= Springtime's foraging treats|accessdate=2008-07-16 |date= [[2007]]-[[01-06]]|work= Life and Health, Guardian.co.uk|publisher= ''[[The Guardian]]''}}</ref> === Food === [[Image:TaoKaeNoi Seaweed.JPG|thumb|Packaged seaweed]] Seaweeds are extensively used as food by coastal people, particularly in East Asia, e.g. [[Japan]], [[China]], [[Korea]], [[Taiwan]], and [[Vietnam]], but also in [[Indonesia]], [[Peru]], the [[Canadian Maritimes]], [[Scandinavia]], [[Ireland]], [[Wales]], [[Philippines]], and [[Scotland]], among other places. [[Tiwi]], [[Albay]] residents discovered a new pansit or [[noodles]] made from seaweed, which has health benefits. It is rich in [[calcium]] and [[magnesium]] and the seaweed noodles can be cooked into pansit canton, pansit luglug, [[spaghetti]] or [[carbonara]].<ref>[http://www.abs-cbnnews.com/storypage.aspx?StoryId=114414 Abs-Cbn Interactive, Albay folk promote seaweed 'pansit']</ref> In Asia, Zicai 紫菜 (in China), [[Gim (Korean food)|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 (seaweed)|laver]] and [[laverbread]], made from oats and the laver, is a popular dish in Wales. Seaweeds are also harvested or cultivated for the extraction of [[alginate]], [[agar]] and [[carrageenan]], gelatinous substances collectively known as [[hydrocolloid]]s or phycocolloids. Hydrocolloids have attained commercial significance, especially in food production as food additives. <ref>Round F.E. 1962 ''The Biology of the Algae.'' Edward Arnold Ltd.</ref> The food industry exploits the gelling, water-retention, emulsifying and other physical properties of these hydrocolloids. Agar is used in foods such as confectionery, meats and poultry products, desserts and beverages and moulded foods. Carrageenan is used in preparation of salad dressings and sauces, dietetic foods, and as a preservative in meat and fish products, dairy items and baked goods. Alginates enjoy many of the same uses as carrageenan, but are also used in production of industrial products such as paper coatings, adhesives, dyes, gels, explosives and in processes such as paper sizing, textile printing, hydro-mulching and drilling. === Medicine === [[Image:Seaweed 600.jpg|thumb|right|Seaweed-covered rocks in the [[United Kingdom|UK]]]] :''See also [[Fucoidan]] In the [[biomedicine]] and pharmaceutical industries, alginates are used in wound dressings, and production of dental moulds and have a host of other applications. In [[microbiology]] research, agar 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.{{Fact|date=February 2007}} Seaweed is also a known source of [[iodine]],<ref>[http://seaweed.ucg.ie/Nutrition/iodine.html Iodine in Seaweed<!-- Bot generated title -->]</ref> an element necessary for [[thyroid]] function with deficiencies leading to [[goitre]]. It has been asserted that seaweeds may have curative properties for [[tuberculosis]], [[arthritis]], colds and [[influenza]], worm infestations and even [[tumors]].[http://www.seaweed.ie/uses_general/MedicinalUses.html] {{Dubious|date=March 2008}} A number of research studies have been conducted to investigate these claims and other effects of seaweed on human health.{{Fact|date=February 2007}} === Other uses === Other seaweeds may be used as [[seaweed fertilizer]].{{fact}} Seaweed is currently being researched as a potential source of [[Biofuel]] in the form of [[bioethanol]].<ref>http://dsc.discovery.com/news/2008/06/23/ireland-seaweed-ethanol.html</ref> Seaweed is also an ingredient in some toothpaste, cosmetics and paints.<ref name="Sun.Star"/> ==References== {{reflist}} == See also == <div style="-moz-column-count:3; column-count:3;"> * [[Algaculture]] * [[Alaria esculenta]] * [[Ascophyllum nodosum]] * [[Biofuel from algae]] * [[Chondrus crispus]] * [[Caulerpa]] * [[Dunaliella bardawil]] * [[Dunaliella salina]] * [[Enteromorpha]] * [[Himanthalia elongata]] * [[Kelp]] * [[Laminaria]] * [[Laver (seaweed)|Laver]] * [[Monostroma]] * [[Ogonori]] * [[Palmaria palmata]] * [[Porphyra]] * [[Scytosiphon lomentaria]] * [[Sea lettuce]] * [[Spirulina]] * [[Trentepohlia]] * [[Wakame]] </div> ==External links== * [http://www.seaweed.ie/ The Seaweed Site], information on all aspects of seaweeds and marine algal biology * [http://www.algaebase.org/ AlgaeBase], a searchable taxonomic, image, and utilization database of freshwater, marine and terrestrial algae, including seaweed. * [http://www.seaweedafrica.org/ SeaweedAfrica], information on seaweed utilisation for the African continent. [[Category:Brown algae]] [[Category:Sea vegetables]] [[Category:Red algae]] [[Category:Algae]] [[Category:Aquatic organisms]] [[de:Seetang]] [[he:אצות]] [[es:Macroalga]] [[fo:Tari]] [[fr:Varech]] [[ko:바닷말]] [[lt:Jūržolės]] [[nl:Zeewier]] [[ja:海藻]] [[no:Tang (alge)]] [[nrm:Vrai]] [[pl:Wodorosty]] [[pt:Macroalga]] [[simple:Seaweed]] [[fi:Merilevä]] [[sv:Tång (växt)]] [[to:limutahi]] [[zh:海苔]]