''Fucus vesiculosus'', known by the common names bladder wrack, black tang, rockweed, sea grapes, bladder fucus, sea oak, cut weed, dyers fucus, red fucus and rock wrack, is a

seaweed Seaweed, or macroalgae, refers to thousands of species of macroscopic, multicellular, marine algae. The term includes some types of '' Rhodophyta'' (red), ''Phaeophyta'' (brown) and ''Chlorophyta'' (green) macroalgae. Seaweed species such as ...

found on the coasts of the North Sea, the western Baltic Sea and the Atlantic and Pacific Oceans. It was the original source of

iodine Iodine is a chemical element with the symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , and boils to a vi ...

, discovered in 1811, and was used extensively to treat goitre, a swelling of the

thyroid gland The thyroid, or thyroid gland, is an endocrine gland in vertebrates. In humans it is in the neck and consists of two connected lobe (anatomy), lobes. The lower two thirds of the lobes are connected by a thin band of Connective tissue, tissue cal ...

related to iodine deficiency.

Description

The fronds of ''F. vesiculosus'' grow to long and wide and have a prominent midrib throughout. It is attached by a basal disc-shaped holdfast. It has almost spherical air bladders, which are usually paired one on either side of the mid-rib but may be absent in young plants. The margin is smooth and the frond is dichotomously branched. It is sometimes confused with ''

Fucus spiralis ''Fucus spiralis'' is a species of seaweed, a brown alga (Heterokontophyta, Phaeophyceae), living on the littoral shore of the Atlantic coasts of Europe and North America. It has the common names of spiral wrack and flat wrack. Description '' ...

'' with which it hybridises and is similar to ''Fucus serratus''.

Distribution

''Fucus vesiculosus'' is a common large alga on the shores of the British Isles. It has been recorded from the Atlantic shores of Europe, Northern Russia, the Baltic Sea, Greenland, Azores,

Canary Islands The Canary Islands (; es, Canarias, ), also known informally as the Canaries, are a Spanish autonomous community and archipelago in the Atlantic Ocean, in Macaronesia. At their closest point to the African mainland, they are west of Morocc ...

, Morocco and

Madeira ) , anthem = ( en, "Anthem of the Autonomous Region of Madeira") , song_type = Regional anthem , image_map=EU-Portugal_with_Madeira_circled.svg , map_alt=Location of Madeira , map_caption=Location of Madeira , subdivision_type=Sovereign st ...

. It is also found on the Atlantic coast of

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

from

Ellesmere Island Ellesmere Island ( iu, script=Latn, Umingmak Nuna, lit=land of muskoxen; french: île d'Ellesmere) is Canada's northernmost and List of Canadian islands by area, third largest island, and the List of islands by area, tenth largest in the world. ...

Hudson Bay Hudson Bay ( crj, text=ᐐᓂᐯᒄ, translit=Wînipekw; crl, text=ᐐᓂᐹᒄ, translit=Wînipâkw; iu, text=ᑲᖏᖅᓱᐊᓗᒃ ᐃᓗᐊ, translit=Kangiqsualuk ilua or iu, text=ᑕᓯᐅᔭᕐᔪᐊᖅ, translit=Tasiujarjuaq; french: b ...

to North Carolina.

Ecology

The species is especially common on sheltered shores from the middle littoral to lower intertidal levels. It is rare on exposed shores, where any specimens may be short, stunted and without the air vesicles. ''F. vesiculosus'' supports few colonial organisms but provides a canopy and shelter for the tube worm '' Spirorbis spirorbis'', herbivorous

isopod Isopoda is an order of crustaceans that includes woodlice and their relatives. Isopods live in the sea, in fresh water, or on land. All have rigid, segmented exoskeletons, two pairs of antennae, seven pairs of jointed limbs on the thorax, an ...

s such as ''

Idotea ''Idotea'' is a genus of isopod crustaceans, mostly from cold temperate waters. The taxonomy of the genus is still in doubt, and many of the currently recognised species may be synonym (taxonomy), taxonomic synonyms, and others may be moved to d ...

'' and surface-grazing snails such as ''

Littorina obtusata ''Littorina obtusata'', common name the flat periwinkle, is a species of sea snail, a marine gastropod mollusk in the family (biology), family Littorinidae, the winkles or periwinkles. Distribution This marine species occurs wherever brown sea ...

''.

Phlorotannin Phlorotannins are a type of tannins found in brown algae such as kelps and rockweeds or sargassacean species, and in a lower amount also in some red algae. Contrary to hydrolysable or condensed tannins, these compounds are oligomers of phlorogl ...

s in ''Fucus vesiculosus'' act as chemical defenses against the marine herbivorous snail '' Littorina littorea''., while

galactolipid Galactolipids are a type of glycolipid whose sugar group is galactose. They differ from glycosphingolipids in that they do not have nitrogen in their composition. They are the main part of plant membrane lipids where they substitute phospholipids ...

s act as herbivore deterrents against the sea urchin ''

Arbacia punctulata The Atlantic purple sea urchin (''Arbacia punctulata'') is a species of sea urchins from the family Arbaciidae, native to the Atlantic Ocean. Description The Atlantic purple sea urchin is a spherical, dark purple-spined sea urchin, with a nea ...

''. Methyl jasmonate may induce the phlorotannins production. Fucophlorethol A is a type of phlorotannin found in ''F. vesiculosus''.

Biology

Plants of ''F. vesiculosus'' are

dioecious Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproductio ...

. Gametes are generally released into the seawater under calm conditions, and the eggs are fertilized externally to produce a zygote. Eggs are fertilized shortly after being released from the receptacle. A study on the coast of Maine showed that there was 100% fertilization at both exposed and sheltered sites. Continuously submerged populations in the Baltic Sea are very responsive to turbulent conditions. High fertilization success is achieved because the gametes are released only when water velocities are low. Individuals of ''F. vesiculosus'' from the North Sea colonized the Baltic Sea less than 8 000 years ago. The event is paralleled by a switch from what seems to be obligate sexual recruitment to facultative asexual recruitment. Asexual reproduction in Baltic Sea populations is accomplished by the production of adventitious branches that come loose and reattach to the bottom by the formation of rhizoids. Adventitious branches are present in thalli of ''F. vesiculosus'' in other areas too but asexual formation of new thalli has never been reported outside the Baltic Sea.

Consumption

''Fucus vesiculosus'' is sold as a nutritional supplement. Primary chemical constituents include mucilage, algin, mannitol, fucitol, beta-carotene, zeaxanthin, volatile oils,

, bromine, potassium and other minerals.

Adverse effects

Consumption of ''F. vesiculosus'' can cause

platelet inhibition Platelets, also called thrombocytes (from Greek θρόμβος, "clot" and κύτος, "cell"), are a component of blood whose function (along with the coagulation factors) is to react to bleeding from blood vessel injury by clumping, thereby ini ...

, which may potentiate the

anticoagulant Anticoagulants, commonly known as blood thinners, are chemical substances that prevent or reduce coagulation of blood, prolonging the clotting time. Some of them occur naturally in blood-eating animals such as leeches and mosquitoes, where the ...

activity of warfarin (Coumadin). It should be avoided before surgery. Some people may suffer an allergic reaction to the iodine in ''F. vesiculosus''.

References

External links

* * * * * * * {{Taxonbar, from=Q754755 Fucales Edible algae Flora of Alaska Edible seaweeds Biota of the Arctic Ocean Biota of the Atlantic Ocean Biota of the Baltic Sea Biota of the North Sea Species described in 1753 Taxa named by Carl Linnaeus Flora without expected TNC conservation status Fucaceae