''Fucus vesiculosus'', known by the common names bladderwrack, 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 North Sea lies between Great Britain, Denmark, Norway, Germany, the Netherlands, Belgium, and France. A sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian Se ...

, the western

Baltic Sea The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by the countries of Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden, and the North European Plain, North and Central European Plain regions. It is the ...

and the

Atlantic The Atlantic Ocean is the second largest of the world's five oceanic divisions, with an area of about . It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for se ...

and

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

s. It was the original source of

iodine Iodine is a chemical element; it has symbol I and atomic number 53. The heaviest of the stable halogens, it exists at standard conditions as a semi-lustrous, non-metallic solid 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 goitre (British English), or goiter (American English), is a swelling in the neck resulting from an enlarged thyroid gland. A goitre can be associated with a thyroid that is not functioning properly. Worldwide, over 90% of goitre cases are ...

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 ''Fu ...

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

Biology

Plants of ''F. vesiculosus'' are

dioecious Dioecy ( ; ; adj. dioecious, ) is a characteristic of certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is ...

Gamete A gamete ( ) is a Ploidy#Haploid and monoploid, haploid cell that fuses with another haploid cell during fertilization in organisms that Sexual reproduction, reproduce sexually. Gametes are an organism's reproductive cells, also referred to as s ...

s 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 Maine ( ) is a U.S. state, state in the New England region of the United States, and the northeasternmost state in the Contiguous United States. It borders New Hampshire to the west, the Gulf of Maine to the southeast, and the Provinces and ...

showed that there was 100% fertilization at both exposed and sheltered sites. Continuously submerged populations in the

are very responsive to turbulent conditions. High

fertilization Fertilisation or fertilization (see American and British English spelling differences#-ise, -ize (-isation, -ization), spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give ...

success is achieved because the

gamete A gamete ( ) is a Ploidy#Haploid and monoploid, haploid cell that fuses with another haploid cell during fertilization in organisms that Sexual reproduction, reproduce sexually. Gametes are an organism's reproductive cells, also referred to as s ...

s 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.

Distribution

''Fucus vesiculosus'' is a common large alga on the shores of the

British Isles The British Isles are an archipelago in the Atlantic Ocean, North Atlantic Ocean off the north-western coast of continental Europe, consisting of the islands of Great Britain, Ireland, the Isle of Man, the Inner Hebrides, Inner and Outer Hebr ...

. It has been recorded from the Atlantic shores of

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

, Northern Russia, the

Greenland Greenland is an autonomous territory in the Danish Realm, Kingdom of Denmark. It is by far the largest geographically of three constituent parts of the kingdom; the other two are metropolitan Denmark and the Faroe Islands. Citizens of Greenlan ...

Azores The Azores ( , , ; , ), officially the Autonomous Region of the Azores (), is one of the two autonomous regions of Portugal (along with Madeira). It is an archipelago composed of nine volcanic islands in the Macaronesia region of the North Atl ...

Canary Islands The Canary Islands (; ) or Canaries are an archipelago in the Atlantic Ocean and the southernmost Autonomous communities of Spain, Autonomous Community of Spain. They are located in the northwest of Africa, with the closest point to the cont ...

, Morocco and

Madeira Madeira ( ; ), officially the Autonomous Region of Madeira (), is an autonomous Regions of Portugal, autonomous region of Portugal. It is an archipelago situated in the North Atlantic Ocean, in the region of Macaronesia, just under north of ...

. It is also found on the Atlantic coast of

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

from

Ellesmere Island Ellesmere Island (; ) 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. It comprises an area of , slightly smaller than Great Britain, and the total ...

Hudson Bay Hudson Bay, sometimes called Hudson's Bay (usually historically), is a large body of Saline water, saltwater in northeastern Canada with a surface area of . It is located north of Ontario, west of Quebec, northeast of Manitoba, and southeast o ...

North Carolina North Carolina ( ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, South Carolina to the south, Georgia (U.S. stat ...

Ecology

The species is especially common on sheltered shores from the middle

littoral The littoral zone, also called litoral or nearshore, is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark (which is rarely i ...

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 ''Spirorbis spirorbis'' or ''Spirorbis borealis'' is a small (3–4 mm) coiled sedentary marine Polychaeta, polychaete worm in the Serpulidae family that lives attached to seaweeds and Zostera, eel grass in shallow saltwater. It is commonly ...

'', herbivorous

isopod Isopoda is an Order (biology), order of crustaceans. Members of this group are called isopods and include both Aquatic animal, aquatic species and Terrestrial animal, terrestrial species such as woodlice. All have rigid, segmented exoskeletons ...

s such as '' Idotea'' and surface-grazing

snails A snail is a shelled gastropod. The name is most often applied to land snails, terrestrial molluscs, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gas ...

such as '' Littorina obtusata''.

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 The common periwinkle or winkle (''Littorina littorea'') is a species of small edible whelk or sea snail, a marine gastropod mollusc that has gills and an operculum, and is classified within the family Littorinidae, the periwinkles. This is a ...

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

Uses

''Fucus vesiculosus'' can be cooked and eaten. It was the original source of

, discovered in 1811, and was used extensively to treat

, a swelling of the

thyroid gland The thyroid, or thyroid gland, is an endocrine gland in vertebrates. In humans, it is a butterfly-shaped gland located in the neck below the Adam's apple. It consists of two connected lobes. The lower two thirds of the lobes are connected by ...

related to

iodine deficiency Iodine deficiency is a lack of the trace element iodine, an essential nutrient in the diet. It may result in metabolic problems such as goiter, sometimes as an endemic goiter as well as congenital iodine deficiency syndrome due to untreated ...

. It is also sold as a nutritional supplement. Primary chemical constituents include

mucilage Mucilage is a thick gluey substance produced by nearly all plants and some microorganisms. These microorganisms include protists which use it for their locomotion, with the direction of their movement always opposite to that of the secretion of ...

, algin,

mannitol Mannitol is a type of sugar alcohol used as a sweetener and medication. It is used as a low calorie sweetener as it is poorly absorbed by the intestines. As a medication, it is used to decrease pressure in the eyes, as in glaucoma, and to l ...

fucitol Fucitol, also known as L-fucitol, 1-deoxy-L-galactitol, and (2''R'',3''S'',4''R'',5''S'')-hexane-1,2,3,4,5-pentol, is a sugar alcohol derived from fucoidan which is found in the North Atlantic seaweed ''Fucus vesiculosus'' or by the reduction of f ...

, beta-carotene,

zeaxanthin Zeaxanthin is one of the most common carotenoids in nature, and is used in the xanthophyll cycle. Synthesized in plants and some micro-organisms, it is the pigment that gives paprika (made from bell peppers), corn, saffron, goji ( wolfberries) ...

, volatile oils, iodine,

bromine Bromine is a chemical element; it has chemical symbol, symbol Br and atomic number 35. It is a volatile red-brown liquid at room temperature that evaporates readily to form a similarly coloured vapour. Its properties are intermediate between th ...

potassium Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to ...

and other

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Mi ...

Adverse effects

Consumption of ''F. vesiculosus'' can cause

platelet inhibition Platelets or thrombocytes () are a part of blood whose function (along with the coagulation factors) is to react to bleeding from blood vessel injury by clumping to form a blood clot. Platelets have no cell nucleus; they are fragments of cyt ...

, which may potentiate the

anticoagulant An anticoagulant, commonly known as a blood thinner, is a chemical substance that prevents or reduces the coagulation of blood, prolonging the clotting time. Some occur naturally in blood-eating animals, such as leeches and mosquitoes, which ...

activity of

warfarin Warfarin, sold under the brand name Coumadin among others. It is used as an anticoagulant, anticoagulant medication. It is commonly used to prevent deep vein thrombosis and pulmonary embolism, and to protect against stroke in people who ha ...

(Coumadin). It should be avoided before surgery. Some people may suffer an

allergic reaction Allergies, also known as allergic diseases, are various conditions caused by hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include Allergic rhinitis, hay fever, Food allergy, food al ...

to the iodine in ''F. vesiculosus''.

References

External links

* * * * * * * {{Authority control 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 Protists described in 1753 Taxa named by Carl Linnaeus Flora without expected TNC conservation status Fucaceae Brown algae species