''Porphyra'' is a genus of coldwater

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 ke ...

s that grow in cold, shallow

seawater Seawater, or salt water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has appr ...

. More specifically, it belongs to red algae phylum of

laver Laver may refer to: * Laver (surname), a list of people with the name * Laver (ghost town), Sweden * Green laver, a type of edible green seaweed used to make laverbread * River Laver, a river in North Yorkshire, England * Lavatorium, a washing fa ...

species (from which comes

laverbread Laverbread (; cy, bara lafwr or '; ga, sleabhac) is a food product made from laver, an edible seaweed (littoral alga) consumed mainly in Wales as part of local traditional cuisine. The seaweed is commonly found around the west coast of Great B ...

), comprising approximately 70 species.Brodie, J.A. and Irvine, L.M. 2003. ''Seaweeds of the British Isles.'' Volume 1 Part 3b. The Natural History Museum, London. It grows in the

intertidal zone The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of habitats with various species ...

, typically between the upper intertidal zone and the splash zone in cold waters of temperate oceans. In East Asia, it is used to produce the sea vegetable products ''

nori Nori is a dried edible seaweed used in Japanese cuisine, made from species of the red algae genus '' Pyropia'', including ''P. yezonesis'' and '' P. tenera''. It has a strong and distinctive flavor, and is often used to wrap rolls of sushi o ...

'' (in Japan) and '' gim'' (in Korea). There are considered to be 60 to 70 species of ''Porphyra'' worldwide Kain, J.M. 1991. Cultivation of attached seaweeds. in Guiry, M.D. and Blunden, G. 1992. ''Seaweed Resources in Europe: Uses and Potential.'' John Wiley and Sons, Chichester and seven around Britain and Ireland where it has been traditionally used to produce edible sea vegetables on the Irish Sea coast.Hardy, F.G. and Guiry, M.D. 2006. ''A Check-list and Atlas of the Seaweeds of Britain and Ireland.'' British Phycological Society, London. The species

Porphyra purpurea ''Porphyra purpurea'' is a medium sized marine algae in the Division Rhodophyta. Description This red algae consists of a single membranous layer of cells forming a blade attached by a disk holdfast (biology), holdfast. It grows to a length of 2 ...

has one of the largest

plastid The plastid (Greek: πλαστός; plastós: formed, molded – plural plastids) is a membrane-bound organelle found in the cells of plants, algae, and some other eukaryotic organisms. They are considered to be intracellular endosymbiotic cyanobac ...

genomes known, with 251 genes.

Life cycle

''Porphyra'' displays a heteromorphic alternation of generations. The

thallus Thallus (plural: thalli), from Latinized Greek (), meaning "a green shoot" or " twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. Many of these organisms ...

we see is the haploid generation; it can reproduce asexually by forming

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, ...

s which grow to replicate the original thallus. It can also reproduce sexually. Both male and female

gamete A gamete (; , ultimately ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. In species that produce ...

s are formed on the one thallus. The female gametes while still on the thallus are fertilized by the released male gametes, which are non-motile. The fertilized, now

diploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respecti ...

, carposporangia after

mitosis In cell biology, mitosis () is a part of the cell cycle in which replicated chromosomes are separated into two new nuclei. Cell division by mitosis gives rise to genetically identical cells in which the total number of chromosomes is maint ...

produce spores ( carpospores) which settle, then bore into shells, germinate and form a filamentous stage. This stage was originally thought to be a different species of alga, and was referred to as ''Conchocelis rosea''. That ''Conchocelis'' was the

stage of ''Porphyra'' was discovered in 1949 by the British phycologist

Kathleen Mary Drew-Baker Kathleen Mary Drew-Baker (6 November 1901 – 14 September 1957) was a British phycologist, known for her research on the edible seaweed '' Porphyra laciniata'' (nori), which led to a breakthrough for commercial cultivation. Kathleen Drew-Ba ...

for the

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located enti ...

an species '' Porphyra umbilicalis''. It was later shown for species from other regions as well.Thomas, D. 2002. ''Seaweeds.'' The Natural History Museum, London.

Food

Most human cultures with access to use it as a food or somehow in the diet, making it perhaps the most domesticated of the marine algae,Mumford, T.F. and Miura, A. 4.''Porphyra'' as food: cultivation and economics. in Lembi, C.A. and Waaland, J.R. 1988. ''Algae and Human Affairs.'' Cambridge University Press, Cambridge. known as

, ( Vietnamese), ''

'' ( Japanese:), ''amanori'' (Japanese), ''zakai'', '' gim'' (

Korean Korean may refer to: People and culture * Koreans, ethnic group originating in the Korean Peninsula * Korean cuisine * Korean culture * Korean language **Korean alphabet, known as Hangul or Chosŏn'gŭl **Korean dialects and the Jeju language ** ...

:), ''zǐcài'' ( Chinese:), karengo, ''sloke'' or ''slukos''. The marine red alga ''Porphyra'' has been cultivated extensively in many

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an ...

n countries as an

edible seaweed Edible seaweed, or sea vegetables, are seaweeds that can be eaten and used for culinary purposes. They typically contain high amounts of fiber. They may belong to one of several groups of multicellular algae: the red algae, green algae, and br ...

used to wrap the rice and fish that compose the Japanese food

sushi is a Japanese dish of prepared , usually with some sugar and salt, accompanied by a variety of , such as seafood, often raw, and vegetables. Styles of sushi and its presentation vary widely, but the one key ingredient is "sushi rice," also ...

and the Korean food '' gimbap''. In Japan, the annual production of ''Porphyra'' species is valued at 100 billion yen (US$1 billion).Aoki, Y. and Kamei, Y. 2006 Preparation of recombinant polysaccharide-degrading enzymes from the marine bacterium, ''Pseudomonas'' sp. ND137 for the production of protoplasts of ''Porphyra yezoensis'' ''Eur. J. Phycol.'' 41: 321-328. is harvested from the coasts of Great Britain and Ireland, where it has a variety of culinary uses including

. In Hawaii, "the species is considered a great delicacy, called ". Porphyra was also harvested by the

Southern Kwakiutl Laich-kwil-tach (also spelled Ligwilda'xw), is the Anglicization of the Kwak'wala autonomy by the "Southern Kwakiutl" people of Quadra Island and Campbell River in British Columbia, Canada. There are today two main groups (of perhaps five origi ...

Haida Haida may refer to: Places * Haida, an old name for Nový Bor * Haida Gwaii, meaning "Islands of the People", formerly called the Queen Charlotte Islands * Haida Islands, a different archipelago near Bella Bella, British Columbia Ships * , a 1 ...

, Seechelt, Squawmish,

Nuu-chah-nulth The Nuu-chah-nulth (; Nuučaan̓uł: ), also formerly referred to as the Nootka, Nutka, Aht, Nuuchahnulth or Tahkaht, are one of the indigenous peoples of the Pacific Northwest Coast in Canada. The term Nuu-chah-nulth is used to describe fift ...

, Nuxalk,

Tsimshian The Tsimshian (; tsi, Ts’msyan or Tsm'syen) are an Indigenous people of the Pacific Northwest Coast. Their communities are mostly in coastal British Columbia in Terrace and Prince Rupert, and Metlakatla, Alaska on Annette Island, the only ...

, and

Tlingit The Tlingit ( or ; also spelled Tlinkit) are indigenous peoples of the Pacific Northwest Coast of North America. Their language is the Tlingit language (natively , pronounced ),

peoples of the North American Pacific coast.

Vitamin B12

Porphyra contains

vitamin B12 Vitamin B12, also known as cobalamin, is a water-soluble vitamin involved in metabolism. It is one of eight B vitamins. It is required by animals, which use it as a cofactor in DNA synthesis, in both fatty acid and amino acid metabolism. It ...

and one study suggests that it is the most suitable non-meat source of this essential vitamin. In the view of the Academy of Nutrition and Dietetics, it may not provide an adequate source of it for

vegan Veganism is the practice of abstaining from the use of animal product—particularly in diet—and an associated philosophy that rejects the commodity status of animals. An individual who follows the diet or philosophy is known as a vegan. ...

Species

Following a major reassessment of the genus in 2011, many species previously included in ''Porphyra'' have been transferred to '' Pyropia'', for example ''

Pyropia tenera ''Pyropia tenera'', also known as gim or nori, is a red algal species in the genus ''Pyropia''. The specific name, ''tenera'', means "delicate" and alludes to its small size. It typically grows to lengths between 20 and 50 cm. It is most ...

'', ''

Pyropia yezoensis ''Pyropia'' is a genus of red algae eaweedin the family Bangiaceae. It is found around the world in intertidal zones and shallow water. The genus has folding frond-like blades which are either red, brown or green. Some ''Pyropia'' species are us ...

'' and the species from New Zealand ''

Pyropia rakiura ''Pyropia rakiura'', formerly known as ''Porphyra rakiura'', is a red alga species in the genus ''Pyropia'', known from New Zealand. It is monostromatic, monoecious, and grows in the intertidal zone, predominantly on rock substrata. With '' P. c ...

'' and ''

Pyropia virididentata ''Pyropia virididentata'', formerly known as ''Porphyra virididentata'', is a red alga species in the genus ''Pyropia.'' It is endemic to New Zealand. It is monostromatic, monoecious, and grows in the intertidal zone, predominantly on rock subs ...

'', leaving only five species out of seventy still within ''Porphyra'' itself.

References

External links

* *
Video footage of Laverbread or Bara Lawr
{{Taxonbar, from=Q2104475 Red algae genera Bangiophyceae Edible seaweeds Seaweeds Edible algae Taxa named by Carl Adolph Agardh