BIOTIC Species Information for Saccharina latissima
|Researched by||Nicola White and Charlotte Marshall||Data supplied by||MarLIN|
|Refereed by||Dr Joanna Jones|
|Scientific name||Saccharina latissima||Common name||Sugar kelp|
|MCS Code||ZR354||Recent Synonyms||None|
|Additional Information||Also known as sugar kelp and sea-belt. The name sugar kelp refers to a whitish, sweet-tasting powder which forms on the dried frond.|
|Mobility/Movement||See additional information
See additional information
|Typical food types||No text entered||Habit||See additional information|
|Bioturbator||Not relevant||Flexibility||High (>45 degrees)|
|Height||Growth Rate||1.1 cm/day|
|Adult dispersal potential||Not relevant||Dependency||Independent|
|General Biology Additional Information||Growth
Laminaria saccharina grows fastest from late winter to spring at a rate of about 1.1 cm/day although growth rates of up to 4.87 cm/day have been recorded. Growth then declines from June onwards and may cease in late summer. The reduction in summer growth rate is thought to be due to nitrate limitation (Sjøtun, 1993). The length:width ratio of newly grown lamina tissue varies throughout the year and is highest during the periods of fast growth, that is, December to June (Sjøtun, 1993). By shifting effort towards growth in width in late summer, it is possible that the plant can maximize the lamina area for autumn and winter and therefore increase the amount of stored carbon available for plants at this time (Sjøtun, 1993).
The seasonal growth pattern results in annual growth rings or lines in the stipe, which can be used to age the plant. The species may occur as an annual opportunist.Morphology
The shape of the frond can vary with environmental conditions. Gerard (1987) found that plants subjected to constant longitudinal tension (as would be expected in higher water flow rates) may become morphologically enhanced to a more streamlined shape. In laboratory simulations, he found that plants subjected to longitudinal stress had significantly narrower blades and a significantly higher rate of cell elongation at the end of the six week experiment, compared to those plants that had not experienced the same stress. Laminaria saccharina plants from wave exposed sites have short, solid stipes and short, narrow and thick tissued fronds with closely wrinkled blades (Lüning, 1990). In contrast, plants from sheltered sites have a broad thin blade with an undulate surface (Lüning, 1990).
|Distribution and Habitat|
|Distribution in Britain & Ireland||All coasts of Britain & Ireland.|
|Global distribution||Recorded from the Atlantic coasts of Europe as far north as Novaya Zemlya and south to northern Portugal and around Iceland. Also found in Greenland, Eastern coast of America down to New Jersey, Pacific coast of America, Bering Straits and Japan.|
|Biogeographic range||Not researched||Depth range||Sublittoral fringe to 30 m|
|Migratory||Non-migratory / Resident|
|Distribution Additional Information||Laminaria saccharina is often found on unstable substrata such as rocks and boulders. The species is adapted to growing on these by having a flexible stipe which reduces leverage on any boulder to which it is attached, reducing the chance of its being turned over by wave movement. The species can even grow unattached and extensive populations can develop on loose-lying sand in calm conditions. In wave-exposed conditions the species may extend into the lower eulittoral.|
Large to very large boulders
|Physiographic preferences||Open coast
Strait / sound
Ria / Voe
|Biological zone||Sublittoral Fringe
|Tidal stream strength/Water flow||Strong (3-6 kn)
Moderately Strong (1-3 kn)
Weak (<1 kn)
Very Weak (negligible)
|Salinity||Full (30-40 psu)
Low (<18 psu)
Reduced (18-30 psu)
Variable (18-40 psu)
|Habitat Preferences Additional Information|
|Reproductive type||Alternation of generations
||Developmental mechanism||Spores (sexual / asexual)
|Reproductive Season||Possibly all year - see additional information.||Reproductive Location|
|Reproductive frequency||Annual episodic||Regeneration potential||No|
|Life span||3-5 years||Age at reproductive maturity||1-2 years|
|Generation time||1-2 years||Fecundity||Insufficient information|
|Egg/propagule size||Insufficient information||Fertilization type||External|
|Reproduction Preferences Additional Information||
Overview of life history
Laminaria saccharina has a typical laminarian life history, in which a macroscopic and structurally complex diploid sporophyte phase alternates with a microscopic haploid gametophyte. The species is a short-lived perennial. Sporophytes (clearly visible adult plants) typically have a life span of 2 to 4 years, although plants may occur as annuals. Specimens over four years old have been recorded from a fjord in Greenland (Borum et al., 2002).
Timing of reproduction
Laminaria saccharina plants usually takes 8 to 15 months to reach fertility at which point the central portion of the blade is covered in unilocular sporangia, that produce zoospores by meiosis. Lüning (1988) reported that sorus (a group of sporangia) formation in Laminaria saccharina from Helgoland, in the Southern North Sea, was restricted to autumn conditions whilst Kain (1979) and Parke (1948) reported that, in the British Isles, sorus formation was most frequent in both autumn and winter. It has been suggested that, in the Arctic, Laminaria saccharina sporophytes may carry sori throughout the year and can therefore produce gametophytes in all seasons (Makarov & Schoschina, 1998, cited in Sjøtun & Schoschina, 2002). Similarly, Parke (1948) reported that in sheltered habitats on the south Devon coast, reproductive tissue was present in all months, although October to April was the most frequent period of spore production in the British Isles for this species.
Factors controlling reproduction
Experimental work using various red and blue light regimes suggest that the onset of fertility in female gametophytes is controlled specifically by blue light above a certain irradiance (Lüning & Dring, 1975). In their experiments, female gametophytes grown in red light for ten days continued to grow vegetatively with no egg production. In contrast, nearly 100% of gametophytes grown in blue light (1.5 nE cm-2 sec-1 (total irradiation per second)) over the same period became fertile. Equally, plants that had been grown in red light for two weeks became fertile after being irradiated with blue light (1-4 nE cm-2 sec-1) for a period of time. After 96 hours of irradiance almost 100% of gametophytes had become fertile. Lüning (1990) also concluded that only blue light induces fertility.
Lüning (1988) cultivated adult sporophytes near Helgoland in the Southern North Sea and cultivated them under various light regimes. Sori were only formed in the 'short day' regime (8:16 hours light:dark respectively). No sori were formed in the 'long day' (16:8) or 'night break' (8:7.5:1:7.5) regimes.
Lüning (1990) found that at 10 °C, the gametophyte could survive at least five months in total darkness.
Lee & Brinkhuis (1988) studied the effects of seasonal light and temperature interactions on the development of Laminaria saccharina gametophytes and juvenile sporophytes in Long Island Sound and found that, in general:
Sjøtun & Schoschina (2002) reported 100 % germination of embyospores at 0 °C in this species suggesting a good adaptation to Arctic conditions.
See 'sensitivity' (adult) section on temperature for further information.