| Laminaria digitata | |
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Scientific classification  | |
| Domain: | Eukaryota |
| Clade: | Diaphoretickes |
| Clade: | SAR |
| Clade: | Stramenopiles |
| Phylum: | Gyrista |
| Subphylum: | Ochrophytina |
| Class: | Phaeophyceae |
| Order: | Laminariales |
| Family: | Laminariaceae |
| Genus: | Laminaria |
| Species: | L. digitata |
| Binomial name | |
| Laminaria digitata | |
Laminaria digitata is a large brown alga in the family Laminariaceae, also known by the common name oarweed. It is found in the sublittoral zone of the northern Atlantic Ocean.
Laminaria digitata is a tough, leathery, dark brown seaweed that grows to two or three metres. The holdfast which anchors it to the rock is conical and has a number of spreading root-like protrusions called rhizoids. The stipe or stalk is flexible and oval in cross section and may be over 1 inch in diameter and grow to 5 feet in length. [1] The blade is large and shaped like the palm of a hand with a number of more or less regular finger-like segments. This seaweed can be distinguished from the rather similar Laminaria hyperborea by being darker in colour and having a shorter stipe that does not easily snap when bent. [2]
The life cycle is of the large diploid sporophytes and microscopic gametophytes. Spores develop in sori which occur over the central part of the blade. [3]
Laminaria digitata occurs in the north west Atlantic from Greenland south to Cape Cod and in the north east Atlantic from northern Russia and Iceland south to France. It is common round the coasts of the British Isles except for much of the east coast of England. [2]
Laminaria digitata is found mostly on exposed sites on shores in the lower littoral where it may form extensive meadows and can be the dominant algal species. It has a fairly high intrinsic growth rate compared to other algae, 5.5% per day, and a carrying capacity of about 40 kg wet weight per square meter. It may reach lengths of about 4 m. It overlaps to a small degree in distribution with Fucus serratus and Alaria esculenta . It is highly susceptible to grazing by sea urchins, among other species. It has low and high light limitation values of about 5 and 70 W per square meter respectively. Its distribution is also limited by salinity, wave exposure, temperature, desiccation and general stress. These and other attributes of the alga are summarized in the publications listed below. [4] [5] [6]
It is a known host of the pathogenic fungus Phycomelaina laminariae . [7]
Laminaria digitata is harvested offshore of France and Morocco for use in manufacturing alginic acid. [8] It is used as an ingredient in some cosmetics. [9]
It was traditionally used as a fertiliser and spread on the land. In the 18th century it was burnt to extract the potash it contained for use in the glass industry. In the 19th century it was used for the extraction of iodine. [10]
Historically, the dried stalks of L digitata, called sea-tangle tents were used in traditional medicine as an abortifacient [11] and for mechanically inducing labour. [12] [13]
Kelps are large brown algae or seaweeds that make up the order Laminariales. There are about 30 different genera. Despite its appearance, kelp is not a plant but a stramenopile, a group containing many protists.
Brown algae are a large group of multicellular algae comprising the class Phaeophyceae. They include many seaweeds located in colder waters of the Northern Hemisphere. Brown algae are the major seaweeds of the temperate and polar regions. Many brown algae, such as members of the order Fucales, commonly grow along rocky seashores. 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 that 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. Some members of the class, such as kelps, are used by humans as food.
Fucus is a genus of brown algae found in the intertidal zones of rocky seashores almost throughout the world.
Palmaria palmata, also called dulse, dillisk or dilsk, red dulse, sea lettuce flakes, or creathnach, is a red alga (Rhodophyta) previously referred to as Rhodymenia palmata. It grows on the northern coasts of the Atlantic and Pacific Oceans. It is a well-known snack food. In Iceland, where it is known as söl, it has been an important source of dietary fiber throughout the centuries.
Ascophyllum nodosum is a large, common cold water seaweed or brown alga (Phaeophyceae) in the family Fucaceae. Its common names include knotted wrack, egg wrack, feamainn bhuí, rockweed, knotted kelp and Norwegian kelp. It grows only in the northern Atlantic Ocean, along the north-western coast of Europe including east Greenland and the north-eastern coast of North America. Its range further south of these latitudes is limited by warmer ocean waters. It dominates the intertidal zone. Ascophyllum nodosum has been used numerous times in scientific research and has even been found to benefit humans through consumption.
Alaria esculenta is an edible seaweed, also known as dabberlocks or badderlocks, or winged kelp, and occasionally as Atlantic Wakame. 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.
Laminaria is a genus of brown seaweed in the order Laminariales (kelp), comprising 31 species native to the north Atlantic and northern Pacific Oceans. This economically important genus is characterized by long, leathery laminae and relatively large size. Some species are called Devil's apron, due to their shape, or sea colander, due to the perforations present on the lamina. Others are referred to as tangle. Laminaria form a habitat for many fish and invertebrates.
Fucus serratus is a seaweed of the north Atlantic Ocean, known as toothed wrack, serrated wrack, or saw rack.
Postelsia palmaeformis, also known as the sea palm or palm seaweed, is a species of kelp and classified within brown algae. It is the only known species in the genus Postelsia. 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.
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, and South America. Distribution of the genus is a marker for climate change, as it relates to oceanic temperatures.
Egregia menziesii is a species of kelp known commonly as feather boa kelp. It is the only species in the monotypic genus Egregia. It is native to the coastline of western North America from Alaska to Baja California, where it is a common kelp of the intertidal zone.
Saccharina latissima is a brown alga, of the family Laminariaceae. It is known by the common names sugar kelp, sea belt, and Devil's apron, and is one of the species known to Japanese cuisine as kombu. It is found in the north Atlantic Ocean, Arctic Ocean and north Pacific Ocean. It is common along the coast of Northern Europe as far south as Galicia Spain. In North America, it is found on the East Coast down to Long Island, although historically extended down to New Jersey and on the West Coast down to the state of Washington. On the coast of Asia, it is found south to Korea and Japan.
Laminaria hyperborea is a species of large brown alga, a kelp in the family Laminariaceae, also known by the common names of tangle and cuvie. It is found in the sublittoral zone of the northern Atlantic Ocean. A variety, Laminaria hyperborea f. cucullata is known from more wave sheltered areas in Scandinavia.
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
Delesseria sanguinea is a red marine seaweed.
Phycodrys rubens is a red marine alga of up to 30 cm long.
Phyllophora crispa is a medium-sized fleshy, marine red alga. This alga forms dense mats of up to 15 cm thickness, which influence environmental factors, thus creating habitat for several associated organisms.
Phyllophora pseudoceranoides, the stalked leaf bearer, is a small marine red alga.
Prasiola stipitata is a small green alga of the family Praiolaceae. This species has been recorded in Iceland, the Faroe Islands, on the Atlantic coasts of North America and Europe as well as on the coasts of Australia and New Zealand. It inhabits cold temperature high-nutrient habitats.
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 L. digitata and L. hyperborea and is at risk from climate change.
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