Alaria (alga)

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Alaria
Alger, Alaria dolichorhachis, Nordisk familjebok.png
Alaria esculenta
Scientific classification Red Pencil Icon.png
Kingdom: Chromista
Phylum: Ochrophyta
Class: Phaeophyceae
Order: Laminariales
Family: Alariaceae
Genus: Alaria
Greville, 1830

Alaria is a genus of brown alga (Phaeophyceae) comprising approximately 17 species. Members of the genus are dried and eaten as a food in Western Europe, China, Korea, Japan (called sarumen), and South America. [1] Distribution of the genus is a marker for climate change, as it relates to oceanic temperatures. [2]

Contents

The most common species, Alaria esculenta is a large brown seaweed common on the shores of the British Isles. [3] It has been studied for its potential for aquaculture. [4]

Description

Alaria is a genus of highly variable brown algae, and a member of the order Laminariales, more commonly known as kelp. It has mature sporophytes as small as 15 centimetres (5.9 in) and as large at 15 metres (49 ft) in length. [2] It does not show definite air-floats. [5] All species’ sporophytes consist of a ramified holdfast, an unbranched cylindrical stipe, and a blade with a percurrent, cartilaginous midrib, [2] Alaria is frequently found with lacerations running from the margin to the midrib caused by the ravages of the sea. [6]

Taxonomy

Alaria the second largest genus of Laminariales, with about 17 currently recognized species. However, due to its highly plastic morphology, the kelp has over 100 specific and subspecific names, which have arisen since it was first described in 1830. These synonyms have been tailored down to the present species through genetic comparisons. [7]

Species

The species currently recognised are:

Distribution

Biogeographical

Alaria is most commonly found in far northern waters of the Pacific and Atlantic oceans, with the greatest variety of species concentrated in the north Pacific. More specifically, it has been found on the coasts of England, Ireland, Scotland, Iceland, Greenland, Denmark, Norway, Japan, China, Korea, Canada, and the United States. [2] [6]

Ecological

Alaria is typically found in the sublittoral zones, at a depth of 3–10 metres (10–33 ft). [8] An important factor in Alaria’s distribution is temperature; it is limited by sea temperature of 16°C. and greater. [2] [8] Presumably due to this factor, and rising sea temperatures, the genus has largely disappeared from the English Channel within the past 100 years. [2] Recent research conducted on Alaria esculenta in the Arctic showed pronounced temperature effects on the photosynthesis and germination of the algae. [8]

Life history

As with all kelps, Alaria demonstrate a heteromorphic, sporic life history, with a macroscopic, dominant sporophyte, and a microscopic gametophyte. Unique to the genus Alaria is that the sori of the unilocular sporangia are restricted to certain blades, the sporophylls. The sporophylls are formed as lateral blades from the stipe. Most species are perennial; after reproduction, the blade sloughs off, leaving the stipe and meristem. The persisting meristem produces a new blade at the beginning of the next growing season. [9]

Uses

Human consumption

In Ireland, Scotland, Greenland, Iceland, Denmark, and the Faroe Islands, the midrib is removed, and the blade and sometimes the leaflets are eaten, [7] although it is not commercially available. [6] It is more commonly eaten in the Far East (China, Japan, and Korea), where seaweed consumption is much more popular than in the West. [6] Seaweeds are considered to be highly nutritious, because typically they are low in fat, and have vitamins and minerals in amounts comparable or superior to terrestrial vegetables. [6] Alaria esculenta, in particular, is an excellent source of protein and iodine. [6]

Also known as...

Related Research Articles

Kelp Large brown seaweeds in the order Laminariales

Kelps are large brown algae seaweeds that make up the order Laminariales. There are about 30 different genera. Despite its appearance, kelp is not a plant; it is a heterokont.

Brown algae A large group of multicellular algae, comprising the class Phaeophyceae

The brown algae, comprising the class Phaeophyceae, are a large group of multicellular algae, including many seaweeds located in colder waters within the Northern Hemisphere. Most brown algae live in marine environments, where they play an important role both as food and as a potential habitat. For instance, Macrocystis, a kelp of the order Laminariales, may reach 60 m (200 ft) in length and forms prominent underwater kelp forests. Kelp forests like these contain a high level of biodiversity. Another example is Sargassum, which creates unique floating mats of seaweed in the tropical waters of the Sargasso Sea that serve as the habitats for many species. Many brown algae, such as members of the order Fucales, commonly grow along rocky seashores. Some members of the class, such as kelps, are used by humans as food.

<i>Fucus</i> Genus of brown algae

Fucus is a genus of brown algae found in the intertidal zones of rocky seashores almost throughout the world.

<i>Alaria esculenta</i> Edible seaweed

Alaria esculenta is an edible seaweed, also known as dabberlocks or badderlocks, or winged kelp. It is a traditional food along the coasts of the far north Atlantic Ocean. It may be eaten fresh or cooked in Greenland, Iceland, Scotland and Ireland. It is the only one of twelve species of Alaria to occur in both Ireland and in Great Britain.

<i>Laminaria</i> Genus of algae

Laminaria is a genus of 31 species of brown algae commonly called "kelp". Some species are also referred to as tangle. 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 the perforations present on the lamina. It is found in the north Atlantic Ocean and the northern Pacific Ocean at depths from 8 to 30 m. Laminaria form a habitat for many fish and invertebrates. 

Laminariaceae Family of brown algal seaweeds, many genera of which are popularly called "kelp"

Laminariaceae is a family of brown algal seaweeds, many genera of which are popularly called "kelp". The table indicates the genera within this family. The family includes the largest known seaweeds: Nereocystis and Macrocystis.

<i>Macrocystis</i> Genus of large brown algae

Macrocystis is a monospecific genus of kelp. This genus contains the largest of all the phaeophyceae or brown algae. Macrocystis has pneumatocysts at the base of its blades. Sporophytes are perennial and the individual may live for up to three years; stipes/fronds within a whole individual undergo senescence, where each frond may persist for approximately 100 days. The genus is found widely in subtropical, temperate, and sub-Antarctic oceans of the Southern Hemisphere and in the northeast Pacific from Baja California to Sitka, Alaska. Macrocystis is often a major component of temperate kelp forests.

<i>Postelsia</i> Species of kelp

Postelsia palmaeformis, also known as the sea palm or palm seaweed, is a species of kelp and classified within brown algae. The sea palm is found along the western coast of North America, on rocky shores with constant waves. It is one of the few algae that can survive and remain erect out of the water; in fact, it spends most of its life cycle exposed to the air. It is an annual, and edible, though harvesting of the alga is discouraged due to the species' sensitivity to overharvesting.

<i>Saccharina japonica</i> species of Phaeophyceae

Saccharina japonica is a marine species of the Phaeophyceae plant, a type of kelp or seaweed, which is extensively cultivated on ropes between the seas of China, Japan and Korea. It is widely eaten in East Asia. A commercially important species, S. japonica is also called ma-konbu (真昆布) in Japanese, dasima (다시마) in Korean and hǎidài (海带) in Chinese. Large harvests are produced by rope cultivation which is a simple method of growing seaweeds by attaching them to floating ropes in the ocean.

<i>Saccharina latissima</i> Species of Phaeophyceae, type of kelp

Saccharina latissima is a brown algae, of the family Laminariaceae. It is known by the common name sugar kelp, and also sea belt and Devil's apron, due to its shape. It is found in the north east Atlantic Ocean, the Pacific Ocean and the Barents Sea south to Galicia in Spain. It is not found in the Bay of Biscay but is common round the coasts of the British Isles. The species is found at sheltered rocky seabeds.

<i>Macrocystis pyrifera</i> Species of kelp

Macrocystis pyrifera, commonly known as giant kelp or giant bladder kelp, is a species of kelp, and one of four species in the genus Macrocystis. Despite its appearance, it is not a plant; it is a heterokont. Giant kelp is common along the coast of the eastern Pacific Ocean, from Baja California north to southeast Alaska, and is also found in the southern oceans near South America, South Africa, Australia, and New Zealand. Individual algae may grow to more than 45 metres long at a rate of as much as 60 cm (2 ft) per day. Giant kelp grows in dense stands known as kelp forests, which are home to many marine animals that depend on the algae for food or shelter. The primary commercial product obtained from giant kelp is alginate, but humans also harvest this species on a limited basis for use directly as food, as it is rich in iodine, potassium, and other minerals. It can be used in cooking in many of the ways other sea vegetables are used, and particularly serves to add flavor to bean dishes.

Pterygophora californica is a large species of kelp, commonly known as stalked kelp. It is the only species in its genus Pterygophora. It grows in shallow water on the Pacific coast of North America where it forms part of a biodiverse community in a "kelp forest".

<i>Macrocystis integrifolia</i> species of Phaeophyceae

Macrocystis integrifolia is one of four species of kelp in the genus Macrocystis which grows to about 6 metres (20 ft) long.

<i>Laminaria pallida</i> A large species of brown seaweed from the west coast of southern Africa

Laminaria pallida, the split-fan kelp, is a species of large brown seaweed of the class Phaeophyceae found from Danger Point on the south coast of South Africa to Port Nolloth, Tristan da Cunha and Gough islands in the Atlantic and Île Saint-Paul in the Indian Ocean.

Lessonia trabeculata is a species of kelp, a brown alga in the genus Lessonia. It grows subtidally off the coasts of Peru and northern and central Chile, with the closely related Lessonia nigrescens tending to form a separate zone intertidally.

Laminaria ochroleuca is a large kelp, an alga in the order Laminariales.. They are commonly known as golden kelp, due to their blade colouration, distinguishing them from Laminaria hyperborea

Saccharina dentigera is a species of brown algae, in the family Laminariaceae. It is native to shallow water in the northeastern Pacific Ocean from the Gulf of Alaska to Baja California.

Phyllariopsis brevipes is a species of large brown algae, found in the subtidal zone in the Mediterranean Sea. It is the type species of the genus. Unlike other large brown macroalgae, it has a habitat requirement to grow on the living thalli of the crustose red alga Mesophyllum alternans.

<i>Laminaria nigripes</i> species of alga

Laminaria nigripes is a species of kelp found in the North Atlantic and North Pacific within Arctic and subarctic waters including Vancouver Island, Haida Gawaii, Greenland, Iceland, Norway, Downeast Maine, and the Bay of Fundy. The species may be found exclusively in the Arctic, but frequent misidentification of samples has led to speculation and debate over whether the actual range is subarctic or Arctic. The species is commonly confused with Laminaria digitata and Laminaria hyperborea and is at risk from climate change.

Pleurophycus gardneri is a species of brown alga. It is a deciduous kelp, primarily found in lower, rocky inter-tidal and shallow, rocky sub-tidal locations and is one of the most abundant kelps found within the Pleurophycus Zone. It is not commonly present deeper in the ocean than 30m and is considered a stipitate kelp. P. gardneri forms aggregates of densities up to 10m−2. These kelp beds reside below giant kelp forests, and were therefore often overlooked by researchers for many years. This kelp has a range from Central California to British Columbia, Canada, with a lifespan of only 3 – 6 years.

References

  1. Sharma, O. P. (2001). Textbook of Algae. McGraw Hill. p. 74. ISBN   978-0-07-451928-8.
  2. 1 2 3 4 5 6 Guiry, M.D.; Guiry, G.M. (2008). "Alaria". AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. Retrieved 2009-02-21
  3. Hardy, F.G. and Guiry, M.D. 2003. A Check-list and Atlas of the Seaweeds of Britain and Ireland
  4. Kraan, S., Tramullas, A.V. and Guiry, M.D. (2000) The edible brown seaweed Alaria esculenta (Phaeophyceae, Laminariales): hybridization, growth and genetic comparisons of six Irish populations. Journal of Applied Phycology12: 1573-1576
  5. Jones, W.E. 1964. The British Phycological Society. ISBN   0-9527115-16A key to the genera of the British Seaweeds. Reprinted from Field Studies Volume 1, (4) pp 1 - 32
  6. 1 2 3 4 5 6 Guiry, M.D., Blunden, G. (1991). Seaweed Resources in Europe. Chichester, West Sussex, England. ISBN   0-471-92947-6, ISBN   978-0-471-92947-5
  7. 1 2 Lane, C.E., Lindstrom, S.C., Saunders, G.W. (2007). A molecular assessment of northeast Pacific Alaria species (Laminariales, Phaeophyceae) with reference to the utility of DNA barcoding. Molecular Phylogenetics and Evolution, 44, 634-648.
  8. 1 2 3 Fredersdorf, J., Muller, R., Becker, S., Wiencke, C., Bischof, K. (2009). Interactive effects of radiation, temperature and salinity on different life history stages of the Arctic kelp Alaria esculenta (Phaeophyceae). Oecologia, 160, 483-492.
  9. Bold, H.C., Wynne, M.J. (1985). ‘’Introduction to the Algae’’. Prentice-Hall Inc, Englewood Cliffs, New Jersey. ISBN   0-13-477746-8