Laminaria hyperborea

Researched ByDr Harvey Tyler-WaltersData Supplied ByMarLIN
Refereed byDr Joanna Jones
Taxonomy
Scientific nameLaminaria hyperboreaCommon nameTangle or cuvie
MCS CodeZR351Recent SynonymsNone
PhylumChromophycotaSubphylum
SuperclassClassPhaeophyceae
SubclassOrderLaminariales
SuborderFamilyLaminariaceae
GenusLaminariaSpecieshyperborea
Subspecies  
Additional InformationOther common names include, redware, cuvy, sea rod, mayweed or Slat mara. The new blade grows below the older from November onwards. The old blade is shed in spring and early summer. Blade and stipe vary with exposure and current. In sheltered conditions the blade has few or no digits and the stipe becomes thin but in exposed conditions the blade is deeply digitate and the stipe becomes thick. The stipe is usually up to 1m long but stipes up to 3m long have been recorded (Parke unpublished, cited in Kain, 1971a).
Taxonomy References Howson & Picton, 1997, Guiry, 2000, Lüning, 1990
General Biology
Growth formForest, Straplike / Ribbonlike, FolioseFeeding methodPhotoautotroph
Mobility/MovementPermanent attachmentEnvironmental positionEpilithic, Epifloral
Typical food typesNot relevantHabitAttached
BioturbatorNot relevantFlexibilityHigh (>45 degrees)
FragilityRobustSizeLarge(>50cm)
HeightGrowth Rate0.94 cm/day
Adult dispersal potentialNoneDependencyIndependent
SociabilitySolitary
Toxic/Poisonous?No
Additional InformationThe adult plant exhibits no gender but the gametophytes are dioecious. The approximate size of male and female gametophytes are given.

Growth
The growth rate during maximal growth is reported.
Adults grow rapidly until about 5 years old. Peak growth occurs during winter (November to June) and stops in summer initiated by a photoperiodic response to day length. The total carbon content of canopy lamina is reported to vary with season reflecting a change in carbohydrate storage (Sjøtun, 1996). Carbon content is high in the summer and autumn and starts to decrease in winter with the onset of growth. The old blade is replaced by a new blade formed between the meristem (top of stripe) and the old blade. Nutrients from the old blade contribute to growth. The old blade is shed in spring to early summer.
In Laminaria hyperborea, the proportion of growth allocated to various regions of the plant is reported to vary with both the age of the plant and its habitat (Sjøtun & Fredriksen, 1995). The proportion of growth allocated to the stipe and hapteron, for instance, increases with exposure, the latter probably helping the plant to remain attached and help it to survive in exposed localities (Sjøtun & Fredriksen, 1995). In one year old plants however, growth mainly occurred in the lamina in order to maximize the area for photosynthesis in the light limited understory.

Biology References Lüning, 1990, Birkett et al., 1998b, Kain, 1979, Jones & Kain, 1967, Kain et al., 1975, Wilkinson, 1995, Sjøtun et al., 1996, Sjøtun & Fredriksen, 1995
Distribution and Habitat
Distribution in Britain & IrelandFound on most coasts of Britain and Ireland. Scarce along the south east coast of Britain due to a lack of suitable substrata.
Global distributionRestricted to the north east Atlantic from the northern coast of Iceland, north to the Russian coast near Murmansk and south to Cape Mondego, mid-Portugal including Norway, Faroes, northern France and northern Spain but absent from the Bay of Biscay.
Biogeographic rangeNot researchedDepth rangeExtreme low water to 47m although usually to ca 30m
MigratoryNon-migratory / Resident
Distribution Additional InformationLaminaria hyperborea is not found in areas influenced by sediment (e.g. sand) scour. Laminaria hyperborea is absent is areas of extreme wave action or currents (e.g. surge gullies) since the stiff stipe is likely to snap or holdfasts tear off. It is also absent from sheltered areas. The upper limit of its distribution may be depressed by wave action, e.g. in St Kilda its upper limit is several metres below MLWS (Birkett et al., 1998b). High irradiances (comparable to direct sunlight) reduce photosynthesis in Laminaria hyperborea, which may explain its absence from intertidal rock pools, where it is replaced by %Laminaria digitata% (Kain et al., 1975). The lower limit of Laminaria hyperborea is determined by light penetration except in the presence of grazing e.g. by Echinus in the Isle of Man (Jones & Kain, 1967; Kain et al. 1974). The lower limit for Laminarians is generally considered to be about 1 percent of surface irradiance (Luning, 1990; Birkett et al., 1998b).
Substratum preferencesBedrock, Large to very large boulders, Cobbles, Pebbles, Artificial (e.g. metal/wood/concrete)Physiographic preferencesOpen coast, Strait / sound, Ria / Voe, Enclosed coast / Embayment
Biological zoneUpper Infralittoral, Lower InfralittoralWave exposureVery Exposed, Exposed, Moderately Exposed
Tidal stream strength/Water flowModerately Strong (1-3 kn), Weak (<1 kn)SalinityFull (30-40 psu)
Habitat Additional Information
Distribution References Lüning, 1990, Norton, 1985, Birkett et al., 1998b, JNCC, 1999, Picton & Costello, 1998, Jones & Kain, 1967, Kain et al., 1975, Erwin et al., 1990, Hardy & Guiry, 2003
Reproduction/Life History
Reproductive typeVegetative, Gonochoristic Developmental mechanismSpores (sexual / asexual)
Reproductive SeasonSeptember to AprilReproductive Location
Reproductive frequencyAnnual protracted Regeneration potentialNo
Life span11-20 yearsAge at reproductive maturity3-5 years
Generation time3-5 yearsFecundityIn excess of 1,000,000
Egg/propagule sizeZoospores ca 5µm acrossFertilization typeExternal
Larvae/Juveniles
Larval/Juvenile dispersal potential1km-10kmLarval settlement periodCan be all year round (see additional information)
Duration of larval stage1 day  
Additional Information
  • Laminaria hyperborea is a perennial and lives for up to 20 years. Longevity is thought to be higher in its northern distribution (Sjøtun et al., 1993).
  • Spores are produced from sori over most of the blade surface (except most distal or proximal areas) over 6-7 weeks in winter (September - April) (Kain, 1975). Most young sporophytes (germlings) appear in spring but can appear all year round depending on conditions (Birkett et al., 1998b).
  • Laminarians exhibit alternation of generations and morphologically distinct reproductive phases.
  • The obvious plant is the sporophyte (diploid) producing vast numbers of meiotic haploid zoospores from 'sori'.
  • The flagellated zoospores are about 5 microns in diameter (Sauvageau, 1918; cited in Kain, 1979) and may be transported at least 5 km from the parent (Jónsson, 1972, cited in Norton, 1992). They lose their flagella after 24 hrs (Kain, 1964) and settle on the available substrata. However, settling rate is dependant on the local currents, therefore larval settling time is probably longer than 1 day (Fredriksen et al., 1995).
  • The zoospores develop into microscopic dioecious gametophytes. These become fertile in 10 days in optimal conditions.
  • Male gametophytes release motile sperm that fertilize eggs of female gametophytes and the resultant zygote develops into the new sporophyte. Mass and rapid sperm release was initiated by adding a drop of sea water, into which female Laminaria hyperborea gametophytes had released eggs, to the male gametophyte culture medium, suggesting the eggs produce pheromones which induce the release of and attract the sperm (Lüning & Müller, 1978).
  • Maturation of the gametophytes can be delayed under less optimal conditions and development remains vegetative. For example, Lüning (1980) reported that fertility, the induction of fertilization in male and female gametophytes, depended on a critical quantum dose of blue light. Fragments of damaged vegetative gametophytes may develop into separate gametophytes (only a few cells are required) hence reproductive potential may be increased. If optimal conditions return the gametophyte may become fertile and produce gametes.
  • Spore production may be inhibited by epifauna such as Membranipora membranacea (sea mat) and endophytes such as Streblonema sp. (Kain, 1975b).
Reproduction References Lüning, 1990, Birkett et al., 1998b, Lein et al., 1991, Kain, 1979, Dieck, 1993, Guiry & Blunden, 1991, Norton, 1992, Lüning, 1980, Lüning & Müller, 1978, Kain, 1975b, Sjøtun et al., 1993