Biology

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.).

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 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

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.

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

Food

Seaweeds are consumed by coastal people, particularly in East Asia, e.g., Japan, China, Korea,Taiwan, Thailand, Cambodia, 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, magnesium and iodine, 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.

Medicine

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. Excess intake of seaweed may raise iodine to toxic levels, however.

Seaweeds may have curative properties for tuberculosis, arthritis, colds and influenza, worm infestations and even tumors.[1]^{[dubious – discuss]}

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.

Health risks

The high iodine content of seaweed can produce iodine toxicity if large amounts of seaweed are consumed.

Rotting seaweed is a potent source of hydrogen sulfide, a highly toxic gas, and has been implicated in some incidents of apparent hydrogen-sulfide poisoning.^[15] It can cause vomiting and diarrhea.

colloquial
KK [kəˋlokwɪəl], DJ [kəˋləukwiəl]
1. 口語的; 會話的

encompass
KK [ɪnˋkʌmpəs], DJ [inˋkʌmpəs]
包含

macroscopic
KK [͵mækrəˋskɑpɪk], DJ [͵mækrəˋskɔpik]
1. 肉眼可見的

microscopic
KK [ˋmaɪkrəˋskɑpɪk], DJ [ˋmaikrəˋskɔpik]
1. 只能從顯微鏡裡看到的; 微小的

-scopic
KK [ˋskɑpɪk], DJ [ˋskɔpik]
(構成形容詞)表示”觀察儀器的”

microscope
KK [ˋmaɪkrə͵skop], DJ [ˋmaikrəskəup]
顯微鏡[C]

scope
KK [skop], DJ [skəup]
1. 範圍, 領域[(+of)]
2. 眼界; 見識[(+of)]

microscopic
KK [ˋmaɪkrəˋskɑpɪk], DJ [ˋmaikrəˋskɔpik]
1. 只能從顯微鏡裡看到的; 微小的

multicellularity
KK [͵mʌltɪ͵sɛljəˋlærətɪ], DJ [͵mʌlti͵seljuˋlæriti]
多細胞(胞腔、格、室、空隙)

multicellular
(a.)多細胞的

cellularity
KK [͵sɛljəˋlærətɪ], DJ [͵seljuˋlæriti]
細胞構成

cellular
KK [ˋsɛljʊlɚ], DJ [ˋseljulə]
細胞的,微孔的

benthic
KK [ˋbɛnθɪk], DJ [ˋbenθik]
底棲的

algae
KK [ˋældʒi], DJ [ˋældʒi:]
(alga的複數) 藻類

alga
KK [ˋældʒi], DJ [ˋældʒi:]
藻類

底棲性海藻 (benthic marine algae)
在台灣海域中，尤其是礁岩地形海岸，時常可見大量的固著性海洋藻類 (benthicmarinealgae) 著生在礁岩上，這些藻類與肉眼無法見到的細小浮游性藻類不同，它們多數肉眼可見，其大小可從數公分至數十公尺長。這些固著性的藻類我們泛稱為海藻 (seaweed)。但就分類學的角度而言，海藻通常包括了綠藻植物門 (Chlorophyta)、褐藻植物門 (Phaeophyta) 及紅藻植物門 (Rhodophyta) 中的海水種類，同時它們具有附著在基質上的能力，並有別於那些終其一生或絕大多時間呈浮游狀態的藻類（又稱浮游藻或植物性浮游生物）。

多細胞藻類 (multicellular algae)

taxonomy
KK [tækˋsɑnəmɪ], DJ [tækˋsɔnəmi]
分類法; 分類學

polyphyletic /ˌpɒlɪfaɪˈlɛtɪk/
polyphyletic group
多系群

phyletic
KK [faɪˋlɛtɪk], DJ [faiˋletik]
【生】系統發生的; 種族的

多系群（英語：Polyphyletic group）在生物系統發生學中，是指一個分類群當中的成員，在演化樹上分別位在相隔著其他分支的分支上；也就是說，該分類群並不包含其所有成員的最近共同祖先。

tuft
KK [tʌft], DJ [tʌft]
1. (頭髮、羽毛、草等的)一簇, 一束

藍綠藻 (Cyanobacteria)

cyano-
KK [ˋsaɪəno], DJ [ˋsaiənəu]
cyan

cyan
KK [ˋsaɪæn], DJ [ˋsaiæn]
青色

Cyan這個英文字一般稱為「青色」，是一種介於藍與綠之間的色彩，也是減法三原色（CMY）之一。

arboreal
KK [ɑrˋborɪəl], DJ [ɑ:ˋbɔ:riəl]
1. 樹木的

non-arboreal 草本的

terrestrial
KK [təˋrɛstrɪəl], DJ [tiˋrestriəl]
1. 地球的; 陸地的

A terrestrial plant 陸生植物

thallus
KK [ˋθæləs], DJ [ˋθæləs]
【植】葉狀體
整個植物體是由單一組織組成，沒有根莖葉植物的本體，稱為葉狀體 (thallus)。在生物學上藻類屬於較低等的植物，相較於其他種植物，在構造上就沒有所謂的根、莖、葉之區別，而這種簡單而未分化的個體稱為「葉狀體」(thallus)。

algal
KK [ˋælgəl], DJ [ˋælgəl]
(像)海藻的

lamina
KK [ˋlæmənə], DJ [ˋlæmənə]
葉身

flatten
KK [ˋflætn], DJ [ˋflætn]
1. 使平坦; 弄平

sorus /s’ɔrəs/
孢子囊群

spore
KK [spor], DJ [spɔ:]
1. 【生】孢子

cluster
KK [ˋklʌstɚ], DJ [ˋklʌstə]
群集體,群,簇,束,球,簇晶

fucus
KK [ˋfjukəs], DJ [ˋfju:kəs]
【植】墨角藻

氣囊 (Air bladder)：囊泡狀，漂浮用。

bladder
KK [ˋblædɚ], DJ [ˋblædə]
1. 【解】膀胱
2. 水生植物的氣囊; 脹大的果皮
3. 囊狀物; 可充氣的囊袋

stipe
KK [staɪp], DJ [staip]
1. 【植】(蕨)葉柄

holdfast
KK [ˋhold͵fæst], DJ [ˋhəuldfɑ:st]
1. 緊握
2. 固著器
海藻為了固著於海底或岩石上，它們有類似根的器官稱「固著器」(Holdfast) 的組織來緊緊抓住海底或岩石。

hapteron /hæptərɒn/ 根狀附著器
藻體基部由多分枝的纖維根狀附著器固著在岩石上。

basal
KK [ˋbes!], DJ [ˋbeisl]
1. 基礎的; 基本的; 根本的

benthic
KK [ˋbɛnθɪk], DJ [ˋbenθik]
底棲的

substrate
KK [ˋsʌbstret], DJ [ˋsʌbstreit]
【生化】底質

benthic substrate

葉身 (blade, lamina)

frond
KK [frɑnd], DJ [frɔnd]
藻體

brackish
KK [ˋbrækɪʃ], DJ [ˋbrækiʃ]
1. 微鹹的, 有鹽味的

半鹹水 (brackish water)

photosynthesis
KK [͵fotəˋsɪnθəsɪs], DJ [͵fəutəuˋsinθəsis]
光合作用

littoral
KK [ˋlɪtərəl], DJ [ˋlitərəl]
沿岸的

沿岸區 (littoral zone)
受到潮汐影響的淺水沿岸區稱為沿岸區 (littoral zone) 或潮間帶 (intertidal zone)。沿岸區包括潮間帶和飛沫帶，受空氣和海水之影響，富有能量和營養，養活最多樣化的群聚。光可穿透至底部，含有大量之有根植物，大部份的有機物在此堆積，此處有根的水生植物多，因而生物種類多樣且數量多。

shingle
KK [ˋʃɪŋg!], DJ [ˋʃiŋgl]
Beach gravel consisting of large smooth pebbles unmixed with finer material.
A stretch of shore or beach covered with such gravel.
礫灘

cobble 圓石（中礫）6.5~25.6 cm
pebble 卵石（小礫）1.7~6.4 cm
gravel 礫石（細礫）0.2~1.6 cm

niche
KK [nɪtʃ], DJ [nitʃ]
1. 壁龕

ecological niche 生態棲位
生態棲位(niche)：指生物個體在生態系內空間的、棲息地的或食物鍊上的生態地位也稱生態位置。如果發生生態棲位重疊的情形，則會出現競爭的情形。依據競爭排除理論：在同一時間空間下，生態棲位完全相同的兩物種無法共存。

elevation
KK [͵ɛləˋveʃən], DJ [͵eliˋveiʃən]
海拔

spray
KK [spre], DJ [sprei]
1. 浪花, 水花, 飛沫[U]

kelp
KK [kɛlp], DJ [kelp]
巨藻

sargassum
KK [sɑrˋgæsəm], DJ [sɑ:ˋgæsəm]
馬尾藻

planktonic /plæŋkt’ɑnɪk/
浮游的

plankton
KK [ˋplæŋktən], DJ [ˋplæŋktən]
(總稱) 浮游生物

rock pools 岩池

tidal pool 潮池
潮池 (tidal pools) 則是退潮之後仍然留有大量海水的洞穴，雖然小型，但具有完整的生態系，生物多樣性很高，是海岸生態觀察很適當的場所。

salinity
KK [səˋlɪnətɪ], DJ [səˋliniti]
鹽度

forage
KK [ˋfɔrɪdʒ], DJ [ˋfɔ:ridʒ]
搜索糧秣; 搜尋

加拿大濱海諸省 (Canadian Maritimes)

maritime
KK [ˋmærə͵taɪm], DJ [ˋmæritaim]
1. 海的; 海事的; 航海的

Scandinavia
KK [͵skændəˋnevɪə], DJ [͵skændiˋneiviə]
1. 斯堪的那維亞半島

菲律賓阿爾拜 (Albay)

magnesium
KK [ˋmægˋniʃɪəm], DJ [ˋmægˋni:ʃiəm]
【化】鎂[U]

iodine
KK [ˋaɪə͵daɪn], DJ [ˋaiədai:n]
1. 碘

moss
KK [mɔs], DJ [mɔs]
1. 苔蘚; 地衣[C][U]

laver
KK [ˋlevɚ]
【植】紫菜(食用)

laver bread
奶油紫菜

oat
KK [ot], DJ [əut]
1. 燕麥; 燕麥屬植物[P]

affectionately
KK [əˋfɛkʃənɪtlɪ], DJ [əˋfekʃnitli]
充滿深情地

nutmeg
KK [ˋnʌt͵mɛg], DJ [ˋnʌt͵meg]
1. 【植】肉豆蔻(樹)[C]

cinnamon
KK [ˋsɪnəmən], DJ [ˋsinəmən]
1. 【植】樟屬的樹; 肉桂, 桂[C]

cultivate
KK [ˋkʌltə͵vet], DJ [ˋkʌltiveit]
1. 耕種, 耕作

alginate
褐藻膠

agar
KK [ˋegɑr], DJ [ˋeigɑ:]
1. 【植】石花菜

gelatinous
KK [dʒəˋlætənəs], DJ [dʒiˋlætinəs]
凝膠狀的

gelatin
KK [ˋdʒɛlətn], DJ [ˋdʒelətin]
凝膠; 明膠; 動物膠[U]

人工皮 (hydrocolloids)

colloid
KK [ˋkɑlɔɪd], DJ [ˋkɔlɔid]
【化】膠體, 膠狀體

藻膠 (Phycocolloid)

phycology
KK [faɪˋkɑlədʒɪ], DJ [faiˋkɔlədʒi]
藻類學; 海藻學

Water Retention 保水

retention
KK [rɪˋtɛnʃən], DJ [riˋtenʃən]
1. 保留; 保持

emulsify
KK [ɪˋmʌlsə͵faɪ], DJ [iˋmʌlsifai]
【化】使乳化

emulsion
KK [ɪˋmʌlʃən], DJ [iˋmʌlʃən]
1. 乳膠; 乳狀液

confectionery
KK [kənˋfɛkʃən͵ɛrɪ], DJ [kənˋfekʃənəri]
1. (總稱) 糕點糖果; 糕點糖果製造

poultry
KK [ˋpoltrɪ], DJ [ˋpəultri]
1. 家禽[U][G]

mould
KK [mold]
模型,鑄造,造型

Carrageenan 角叉藻

dietetic
KK [͵daɪəˋtɛtɪk], DJ [͵daiiˋtetik]
飲食的; 食物療法的; 飲食學的

microbiology
KK [͵maɪkrobaɪˋɑlədʒɪ], DJ [ˋmaikrəubaiˋɔlədʒi]
微生物學

extensively
KK [ɪkˋstɛnsɪvlɪ], DJ [ikˋstensivli]
廣大地; 廣泛地

medium
KK [ˋmidɪəm]
【生】培養基

thyroid
KK [ˋθaɪrɔɪd], DJ [ˋθairɔid]
【解】甲狀腺的; 甲狀軟骨的; 盾狀的

goiter
KK [ˋgɔɪtɚ], DJ [ˋgɔitə]
【醫】甲狀腺腫

tuberculosis
KK [tju͵bɝkjəˋlosɪs], DJ [tju:͵bə:kjuˋləusis]
【醫】結核病[U]

arthritis
KK [ɑrˋθraɪtɪs], DJ [ɑ:ˋθraitis]
【解】關節炎

infestation
KK [ɪnfɛsˋteʃən], DJ [͵infesˋteiʃən]
感染

worm infestations 蟲感染

束胃帶手術 (Gastric Banding)

gastric
KK [ˋgæstrɪk], DJ [ˋgæstrik]
胃的

bioethanol
生物酒精; 生質酒精

ethanol
KK [ˋɛθə͵nol], DJ [ˋeθə͵nɔl]
【化】乙醇, 酒精

toothpaste
KK [ˋtuθ͵pest], DJ [ˋtu:θpeist]
牙膏[U]

paste
KK [pest], DJ [peist]
1. 漿糊

紙張上光 Paper Coating

adhesive
KK [ədˋhisɪv], DJ [ədˋhi:siv]
膠黏劑

explosive
KK [ɪkˋsplosɪv]
爆炸物; 炸藥[C][U]

噴漿法 (hydro-mulching)

mulch
KK [mʌltʃ], DJ [mʌltʃ]
以護蓋物覆蓋

toxicity
KK [tɑkˋsɪsətɪ], DJ [tɔkˋsisəti]
毒性, 毒力

硫化氫（hydrogen sulfide）

sulfide
KK [ˋsʌlfaɪd], DJ [ˋsʌlfaid]
【化】硫化物[C][U]

sulfur
KK [ˋsʌlfɚ], DJ [ˋsʌlfə]
1. 【化】硫(磺)

implicate
KK [ˋɪmplɪ͵ket], DJ [ˋimplikeit]
1. 牽連; 連累

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Tag: Biology

The Sun as a White Dwarf Star

Seaweed