Laminaria hyperborea

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Laminaria hyperborea
Scientific classification Edit this 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
(
Foslie, 1884 [1]
Synonyms
  • Fucus hyperboreus Gunnerus, 1766
  • Laminaria cloustonii Edmondston, 1845
  • Laminaria hyperborea f. compressa Foslie, 1884 [1]

Laminaria hyperborea is a

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]

Description

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.

Distribution and habitat

The range is the northeast

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]

Biology

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

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]

Ecology

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

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]

A jar of vegetarian imitation caviar made from L. hyperborea.

Uses

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.

References

Wikimedia Commons has media related to Laminaria hyperborea.
  1. ^ a b Laminaria hyperborea (Gunnerus) Foslie, 1884 World Register of Marine Species. Retrieved 2011-09-22.
  2. ^ Athanasiadis, A. (1996). Taxonomisk litteratur och biogeografi av Skandinaviska rödalger och brunalger. pp. 280. Göteborg: Algologia.
  3. ^ a b Newton, L. 1931. A Handbook of the British Seaweeds. British Museum, London
  4. ^ a b Laminaria hyperborea (Gunnerus) Foslie The Seaweed Site.
  5. S2CID 86008741
    .
  6. ^ Sjøtun, Kjersti; Fredriksen, Stein; LEIN, TE; Rueness, Jan; Sivertsen, Knut (June 1993). "Population studies of Laminaria hyperborea from its northern range of distribution in Norway". Hydrobiologia. 261. Retrieved 13 June 2021.
  7. ^ Laminaria hyperborea (Gunnerus) Foslie AlgaeBase. Retrieved 2011-09-22.
  8. ^ a b c d Tangle or cuvie - Laminaria hyperborea Marine Life Information Network. Retrieved 2011-09-22.
  9. doi:10.1093/icesjms/fsp195
    .
  10. doi:10.1093/icesjms/fsp195
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  11. S2CID 86300158
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  12. S2CID 85627390
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  13. S2CID 84255327
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  14. S2CID 84534494
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  15. ^ Norderhaug, K.M., Christie, H., 2009. Sea urchin grazing and kelp re-vegetation in the NE Atlantic. Marine Biology Research 5, 515-528.
  16. ^ Ecological relationships UK Marine Special Areas of Conservation. Retrieved 2011-09-22.
  17. ^ a b c d Species distribution and habitat exploitation of fauna associated with kelp (Laminaria hyperborea) along the Norwegian Coast Retrieved 2011-09-22.
  18. hdl:1956/4611
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  19. ^ The Nematode Fauna Associated With Holdfasts of Kelp (Laminaria hyperborea) in North-East Britain Journal of the Marine Biological Association of the United Kingdom, 1971. Retrieved 2011-09-22.
  20. doi:10.1016/0141-1136(80)90057-4
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  21. doi:10.1016/0022-0981(74)90044-6
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  22. ^ McHugh, D.J. 1987 (ed.), 1987. Production and utilization of products from commercial seaweeds. FAO Fish.Tech.Pap., (288):189 p. Retrieved 2011-09-22.
  23. ^ Scottish plant uses: Laminaria hyperborea Retrieved 2011-09-22.
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