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Dulse

Dulse

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Palmaria palmata Kuntze, also called dulse, dillisk, dilsk, red dulse, sea lettuce flakes or creathnach, is a red alga
Red algae
The red algae are one of the oldest groups of eukaryotic algae, and also one of the largest, with about 5,000–6,000 species  of mostly multicellular, marine algae, including many notable seaweeds...

 (Rhodophyta) previously referred to as Rhodymenia palmata (Linnaeus) Greville. It grows on the northern coasts of the Atlantic
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...

 and Pacific
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

 oceans. It is a well-known snack food. In Iceland
Iceland
Iceland , described as the Republic of Iceland, is a Nordic and European island country in the North Atlantic Ocean, on the Mid-Atlantic Ridge. Iceland also refers to the main island of the country, which contains almost all the population and almost all the land area. The country has a population...

, where it is known as söl, it has been an important source of fiber throughout the centuries.

History


The earliest record of this species is of St Columba's monks harvesting it 1,400 years ago.

Description


Dulse grows attached by its discoid holdfast
Holdfast
A holdfast is a root-like structure that anchors aquatic sessile organisms, such as seaweed, other sessile algae, stalked crinoids, benthic cnidarians, and sponges, to the substrate. ...

 to the stipes of Laminaria
Laminaria
Laminaria is a genus of 31 species of brown algae , all sharing the common name "kelp". This economically important genus is characterized by long, leathery laminae and relatively large size. Some species are referred to by the common name Devil's apron, due to their shape, or sea colander, due to...

or to rocks. It has a short stipe
Stipe (botany)
In botany, a stipe is a stalk that supports some other structure. The precise meaning is different depending on which taxonomic group is being described....

, the fronds are variable and vary in colour from deep-rose to reddish-purple and are rather leathery in texture. The flat foliose blade gradually expands and divides into broad segments ranging in size to 50 cm long and 3 cm–8 cm in width which can bear flat wedge-shaped proliferations from the edge.

The reference to Rhodymenia palmata var.mollis in Abbott and Hollenberg (1976), is now considered to refer to a different species: Palmaria mollis (Setchel et Gardner) van der Meer et Bird.

Dulse is similar to another seaweed
Seaweed
Seaweed is a loose, colloquial term encompassing macroscopic, multicellular, benthic marine algae. The term includes some members of the red, brown and green algae...

 Dilsea carnosa
Dilsea carnosa
Dilsea carnosa, commonly known as the poor man's weather glass or the sea belt, is a species of red algae in the Dumontiaceae family of the order Gigartinales.-Taxonomy:...

(Schmidel) Kuntze, Dilsea, however, is more leathery with blades up to 30 cm long and 20 cm wide. Unlike Palmaria palmata it is not branched and does not have proliferations or branches from the edge of the frond. The older blades may split, however.

Life history


The full life-history was not fully explained until 1980. Tetraspores occur in scattered sori on the mature blade, which is diploid. Spermatial sori occur scattered over most of the frond of the haploid male plant. The female gametophyte
Gametophyte
A gametophyte is the haploid, multicellular phase of plants and algae that undergo alternation of generations, with each of its cells containing only a single set of chromosomes....

 is very small stunted or encrusted, the carpogonia apparently occurring as single cells in the young plants. The male plants are blade-like and produce spermatia which fertilize the carpogonia of the female crust. After fertilization the diploid plant overgrows the female plant and develops into the tetrasporangial diploid phase attached to the female gametophyte. The adult foliose tetrasporophyte produces tetraspores meiotically. It is therefore usually the diploid tetrasporic phase or the male plant which is to be found on the shore.

Ecology


Palmaria palmata is to be found growing from mid-tide of the intertidal zone
Intertidal zone
The intertidal zone is the area that is above water at low tide and under water at high tide . This area can include many different types of habitats, with many types of animals like starfish, sea urchins, and some species of coral...

 (the area between the high tide and low tide) to depths of 20 m or more in sheltered and exposed shores.

As a food



Dulse is a good source of minerals and vitamins compared with other vegetables, contains all trace elements needed by humans, and has a high protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 content.

It is commonly found from June to September and can be picked by hand when the tide is out. When picked, small snails, shell pieces and other small particles can be washed or shaken off and the plant then spread to dry. Some gatherers may turn it once and roll it into large bales to be packaged later. It is also used as fodder for animals in some countries.

Dulse is commonly used in Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

, Iceland
Iceland
Iceland , described as the Republic of Iceland, is a Nordic and European island country in the North Atlantic Ocean, on the Mid-Atlantic Ridge. Iceland also refers to the main island of the country, which contains almost all the population and almost all the land area. The country has a population...

, Atlantic Canada
Atlantic Canada
Atlantic Canada is the region of Canada comprising the four provinces located on the Atlantic coast, excluding Quebec: the three Maritime provinces – New Brunswick, Prince Edward Island, and Nova Scotia – and Newfoundland and Labrador...

 and the Northeast United States both as food and medicine. It can be found in many health food
Health food
The term health food is generally used to describe foods that are considered to be beneficial to health, beyond a normal healthy diet required for human nutrition. However, the term is not precisely defined by national regulatory agencies such as the U.S...

 stores or fish markets and can be ordered directly from local distributors. In Ballycastle
Ballycastle
Ballycastle can refer to:*Ballycastle, County Antrim, a small town in Northern Ireland*Ballycastle, County Mayo, a village in the Republic of Ireland...

, Northern Ireland, it is traditionally sold at the Ould Lammas Fair
Ould Lammas Fair
The Auld Lammas Fair is a traditional fair held in Ballycastle, County Antrim, Northern Ireland every year on the last Monday and Tuesday of August. It is associated with the Lammas harvest festival....

. It is particularly popular along the Causeway Coast
Giant's Causeway
The Giant's Causeway is an area of about 40,000 interlocking basalt columns, the result of an ancient volcanic eruption. It is located in County Antrim on the northeast coast of Northern Ireland, about three miles northeast of the town of Bushmills...

. Although a fast-dying tradition, there are many who still gather their own dulse. In County Antrim, it is eaten dried and uncooked in a manner similar to that in which one would eat snacks at a drinks party. It is also used in cooking. (Its properties are similar to those of a flavour-enhancer). It is commonly referred to as dillisk on the west coast of Ireland. Dillisk is usually dried and sold as a snack food from stalls in seaside towns by periwinkle-sellers.

Waste pipes have spoiled some sites.

Fresh dulse can be eaten directly off the rocks before sun-drying. Sun-dried dulse is eaten as is or is ground to flakes or a powder. In Iceland the tradition is to eat it with butter
Butter
Butter is a dairy product made by churning fresh or fermented cream or milk. It is generally used as a spread and a condiment, as well as in cooking applications, such as baking, sauce making, and pan frying...

. It can also be pan fried
Pan frying
Pan frying is a form of frying characterized by the use of minimal cooking oil or fat ; typically using just enough oil to lubricate the pan...

 quickly into chips, baked in the oven covered with cheese
Cheese
Cheese is a generic term for a diverse group of milk-based food products. Cheese is produced throughout the world in wide-ranging flavors, textures, and forms....

, with salsa
Salsa (sauce)
Salsa may refer to any type of sauce. In American English, it usually refers to the spicy, often tomato based, hot sauces typical of Mexican and Central American cuisine, particularly those used as dips. In British English, the word typically refers to salsa cruda, which is common in Mexican ,...

, or simply microwaved briefly. It can also be used in soups, chowders, sandwiches and salads, or added to bread/pizza dough
Dough
Dough is a paste made out of any cereals or leguminous crops by mixing flour with a small amount of water and/or other liquid. This process is a precursor to making a wide variety of foodstuffs, particularly breads and bread-based items , flatbreads, noodles, pastry, and similar items)...

. Finely diced, it can also be used as a flavour enhancer in meat
Meat
Meat is animal flesh that is used as food. Most often, this means the skeletal muscle and associated fat and other tissues, but it may also describe other edible tissues such as organs and offal...

 dishes, such as chili
Chili con carne
Chili con carne is a spicy stew. The name of the dish derives from the Spanish chile con carne, "chili pepper with meat". Traditional versions are made, minimally, from chili peppers, garlic, onions, and cumin, along with chopped or ground beef. Beans and tomatoes are frequently included...

, in place of monosodium glutamate
Monosodium glutamate
Monosodium glutamate, also known as sodium glutamate or MSG, is the sodium salt of glutamic acid, one of the most abundant naturally occurring non-essential amino acids....

.

Dulse contains iodine
Iodine
Iodine is a chemical element with the symbol I and atomic number 53. The name is pronounced , , or . The name is from the , meaning violet or purple, due to the color of elemental iodine vapor....

, which prevents goiter.

Distribution


Palmaria palmata is the only species of Palmaria found on the coast of Atlantic Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

. It is to be found from Portugal
Portugal
Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...

 to the Baltic
Baltic Sea
The Baltic Sea is a brackish mediterranean sea located in Northern Europe, from 53°N to 66°N latitude and from 20°E to 26°E longitude. It is bounded by the Scandinavian Peninsula, the mainland of Europe, and the Danish islands. It drains into the Kattegat by way of the Øresund, the Great Belt and...

 coasts also on the coasts of Iceland and the Faroe Islands
Faroe Islands
The Faroe Islands are an island group situated between the Norwegian Sea and the North Atlantic Ocean, approximately halfway between Scotland and Iceland. The Faroe Islands are a self-governing territory within the Kingdom of Denmark, along with Denmark proper and Greenland...

. It also grows on the shores of Arctic Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

, Arctic Canada, Atlantic Canada, Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...

, Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

 and Korea
Korea
Korea ) is an East Asian geographic region that is currently divided into two separate sovereign states — North Korea and South Korea. Located on the Korean Peninsula, Korea is bordered by the People's Republic of China to the northwest, Russia to the northeast, and is separated from Japan to the...

. The records from California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

 are of Palmaria mollis which is considered a different species.

Infections, galls, malformations and diseases


Galls, possibly produced by nematodes, copepods and bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

are known to infect these plants. They were recorded as "outgrowths of tissue produced by the presence...of an animal."

Further reading

  • Grubb, V.M. 1923. Preliminary note on the reproduction of Rhodymenia palmata, Ag. Ann. Bot. 37: 151–52.

  • Pueschel, C.M. 1979. Ultrastructure of the tetrasporogenesis in Palmaria palmata (Rhodophyta). J. Phycol. 15: 409–424.
  • South, G.R. and Hooper, R.G. 1980. A Catalogue and Atlas of the Benthic Marine Algae of the Island of Newfoundland. pp. 1–136. Memorial University of Newfoundland Occasional Papers in Biology.

External links



  • AlgaeBase
  • http://www.seaweed.ie/descriptions/Palmaria_palmata.html l Michael Guiry's Seaweed Site