Laminaria hyperborea | |
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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. hyperborea |
Binomial name | |
Laminaria hyperborea | |
Synonyms | |
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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 (P.Svensden & J.M.Kain, 1971) is known from more wave sheltered areas in Scandinavia. [2]
Laminaria hyperborea is a massive, leathery seaweed, up to 360 cm long. [3] The holdfast is large and cone-shaped, with branched rhizoids, looking rather like a bird's foot. The stipe is circular in cross section, rough, thick at the base and tapering upwards. Older stipes are often covered with epiphytic red algae. The laminate blade is deeply divided into linear segments and is yellowish brown with large digitate segments. [4] [3] It is a long-lived species and has been recorded as surviving for 15 years. [5]
Laminaria hyperborea can be distinguished from the rather similar L. digitata by being paler in colour and having a longer stipe which snaps when it is bent sharply. [4] Laminaria ochroleuca is also similar but is more yellow in colour and does not have the rough stipe found in L. hyperborea.
The range is the northeast Atlantic Ocean (including the Baltic and North Seas), from the North Cape, Norway and the Kola Peninsula south to central Portugal. [6] [7]
Laminaria hyperborea grows on rocks in the sublittoral zone at depths down to about 10 m (35 ft) in turbid waters and down to 30 m (100 ft) where the water is clear. [8] It tends to be the dominant species in a narrow zone near low-water at spring tides. It also predominates in deeper waters on stable substrates in eave exposed areas [9] while Saccharina latissima tends to be dominant in sheltered areas [10] or those with less stable substrates. [11] Down to about 15 m (50 ft) the growth may be very dense and may be referred to as a "kelp forest" but at greater depths there is a more open community and these areas have been referred to as "parks". [12]
In young individuals of L. hyperborea, the annual growth consists mainly of the enlargement of the blade. This maximises the photosynthetic opportunity while the plant's low stature causes it to be overshadowed. In later years, more growth takes place in the stipe and holdfast. A new frond grows annually in the spring from the top of the stipe. The old frond is sloughed off later after much of its nutrient content has been transferred to the new growth. [8]
Laminaria hyperborea can liberate upward of a million zoospores from sori on the surface of the blade during the course of a few weeks during the winter. These have flagella and settle after about 24 hours before developing into microscopic gametophytes which become fertile in about 10 days. Male gametophytes release large quantities of motile sperm, apparently stimulated to do so by the release of female gametes by the female gametophytes in the vicinity. The fertilised zygotes germinate into young sporophytes which will grow into the mature seaweed. [8] Sexual reproduction is dependent on a minimum quantity of blue light; under less than optimal conditions, the gametophytes may develop vegetatively instead. [8]
Kelp beds provide a nursery area for many marine species and a biodiverse habitat. [13] [14] The grazing behaviour of sea urchins, particularly the green sea urchin, Strongylocentrotus droebachiensis , restricts the development of new growth of L. hyperborea. If the urchins become too numerous, whole areas normally dominated by kelp may become "urchin barrens", [15] denuded of kelp and supporting a much less biodiverse community based on encrusting coralline algae. [16]
Laminaria hyperborea is host to a large and diverse community of invertebrates. In one study in Norway, up to 238 species of benthic macrofauna were found associated with it, with a density of 8000 individuals per kelp plant. [17] The blades were the part of the plant least populated by invertebrates. They were however covered by a bacterial biofilm in which Planctomycetota and Alphaproteobacteria were found all year long and other bacteria occurred seasonally. [18] The stipes, being rough, provided good anchor points for Palmaria palmata and several other species of red algae. The resulting epiphytic growth was home to a range of species of gastropods, amphipods and other invertebrates. [17] Depending upon the season and density of the L. hyperborea bed, the total number of these animals varied; at one location, it ranged from a small number to over 80,000 individuals living on a single stipe. [17] The holdfasts offered a sheltered refuge and housed a large number of mobile macrofauna, a community that was quite different from that on the stipes. [17]
In a study undertaken on the north east coast of Britain, 61 different species of nematode were found living in the holdfasts of L. hyperborea. The majority of these were omnivores feeding on deposits or herbivores feeding on the epiphytic algae growing on the kelp. [19]
In another study comparing the macrofauna resident in the holfasts of L. hyperborea round the coasts of Britain, it was found that, except for the suspension feeders, there was an inverse relationship between the richness of the flora and the pollution, as measured by the heavy metal content of the water, and its clarity. [20]
The calorific values and biomass of L. hyperborea have been studied with regard to its possible use as a fuel. A study found that it could produce annual increases in biomass of 16.5 and 8.0 metric tons of organic matter per hectare at depths of 3 and 9 metres respectively. [21]
Alginates can be extracted from L. hyperborea. In France, Ireland, Scotland and Norway, stipes cast up on beaches are collected for this purpose and in Norway some kelp is harvested by trawling. [22]
Because of its ability to absorb and retain water, L. hyperborea has been used in wound dressings to prevent adhesions. It has also been used to help dilate the cervix during childbirth. [23]
Laminaria hyperborea can also be used for human consumption. For example, it is used to make vegetarian (vegan) imitation caviar.
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, comprising the class Phaeophyceae, are a large group of multicellular algae, including many seaweeds located in colder waters within the Northern Hemisphere. Brown algae are the major seaweeds of the temperate and polar regions. They are dominant on rocky shores throughout cooler areas of the world. 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.
Kelp forests are underwater areas with a high density of kelp, which covers a large part of the world's coastlines. Smaller areas of anchored kelp are called kelp beds. They are recognized as one of the most productive and dynamic ecosystems on Earth. Although algal kelp forest combined with coral reefs only cover 0.1% of Earth's total surface, they account for 0.9% of global primary productivity. Kelp forests occur worldwide throughout temperate and polar coastal oceans. In 2007, kelp forests were also discovered in tropical waters near Ecuador.
Nereocystis is a monotypic genus of subtidal kelp containing the species Nereocystis luetkeana. Some English names include edible kelp, bull kelp, bullwhip kelp, ribbon kelp, bladder wrack, and variations of these names. Due to the English name, bull kelp can be confused with southern bull kelps, which are found in the Southern Hemisphere. Nereocystis luetkeana forms thick beds on subtidal rocks, and is an important part of kelp forests.
Fucus is a genus of brown algae found in the intertidal zones of rocky seashores almost throughout the world.
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.
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.
Macrocystis is a monospecific genus of kelp with all species now synonymous with Macrocystis pyrifera. It is commonly known as giant kelp or bladder 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.
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.
Saccorhiza polyschides, common name furbellow, is a large brown algae of the lower shore and is the largest seaweed found in Europe.
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 kelps provide essential nursery habitat for fisheries and other marine species and thus protect food sources; other species, such as planktonic algae, play a vital role in capturing carbon, producing at least 50% of Earth's oxygen.
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.
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, the coast of North America north of Massachusetts and central California, and the coast of Asia south to Korea and Japan.
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". It is sometimes also referred to as woody-stemmed kelp, walking kelp, or winged kelp.
Aquaculture of giant kelp, Macrocystis pyrifera, is the cultivation of kelp for uses such as food, dietary supplements or potash. Giant kelp contains iodine, potassium, other minerals vitamins and carbohydrates.
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.
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.
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