Saccorhiza polyschides

Researched By	Nicola White	Data Supplied By	MarLIN
Refereed by	This information is not refereed.
Taxonomy
Scientific name	Saccorhiza polyschides	Common name	Furbelows
MCS Code	ZR359	Recent Synonyms	Saccorhiza bulbosa
Phylum	Chromophycota	Subphylum
Superclass		Class	Phaeophyceae
Subclass		Order	Laminariales
Suborder		Family	Phyllariaceae
Genus	Saccorhiza	Species	polyschides
Subspecies
Additional Information	No text entered
Taxonomy References	Norton, 1970, Norton & Burrows, 1969
General Biology
Growth form	Forest, Foliose	Feeding method	Photoautotroph
Mobility/Movement	Permanent attachment	Environmental position	Epilithic, Epifloral
Typical food types	Not relevant	Habit	Attached
Bioturbator	Not relevant	Flexibility	High (>45 degrees)
Fragility	Robust	Size	Large(>50cm)
Height		Growth Rate	145 mm/week
Adult dispersal potential	None	Dependency	Independent
Sociability	Solitary
Toxic/Poisonous?	No
Additional Information	Saccorhiza polyschides is a fast growing, annual and opportunistic species. The obvious plant is a gender-less sporophyte which grows up to 4 m long and may grow at 2 m a month at the peak of the growth season in late spring. The large sporophytes are present on the shore from May until winter. In autumn they commence fruiting and start to decay, leaving behind the bulbous holdfast, which remains on the shore until it is washed off in late winter. The unusual holdfast of Saccorhiza polyschides is formed from a hollow bulbous growth above the sapling holdfast which expands to overwhelm it, sending out secondary haptera to attach to the substratum. The shape of the frond varies with the degree and nature of water movement. In sites of low water current plants produce broad undivided fronds, while those in areas of strong currents have long deeply divided fronds. Plants from wave exposed locations have short fronds divided into few sections. Experiments have shown that these variations are due to phenotypic rather than genotypic variation (Norton, 1978).
Biology References	Norton, 1970, Norton & Burrows, 1969, Norton, 1978, Birkett et al., 1998(b)
Distribution and Habitat
Distribution in Britain & Ireland	Recorded from the all coasts of Britain and Ireland, but absent from Northumberland to the Solent.
Global distribution	Recorded from the coast of Norway as far north as Rorvik. It extends south to Britain, Ireland, France, Spain, and Morocco as far as Cape Jubi. It also penetrates into the eastern Mediterranean and there are isolated reports from the coast of Italy.
Biogeographic range	Not researched	Depth range	0 -35m
Migratory	Non-migratory / Resident
Distribution Additional Information	Saccorhiza polyschides colonizes abraded surfaces such as sand-scoured rocks or boulders that are mobile in winter and is characteristic of much disturbed substrata. Plants grow to a maximum depth of 35 metres in Cornwall. The lower depth limit of the plants may be controlled by grazing from the sea urchin %Echinus esculentus%. When urchins have been removed, the lower limit of Saccorhiza polyschides has been found to extend by 3m. The species is not found in areas of reduced salinity. Lowered salinity reduces the rate of development and growth is irreversibly inhibited below 9 psu. The species competes for space with %Laminaria hyperborea% and the upper limit of Saccorhiza polyschides is related to the lower limit of %Laminaria hyperborea%. Where %Laminaria hyperborea% is absent the species may extend up to the extreme low water springs mark.
Substratum preferences	Bedrock, Large to very large boulders, Small boulders, Cobbles, Pebbles	Physiographic preferences	Open coast, Offshore seabed, Strait / sound, Sealoch, Ria / Voe
Biological zone	Sublittoral Fringe, Upper Infralittoral	Wave exposure	Moderately Exposed, Sheltered, Very Sheltered, Extremely Sheltered, Ultra Sheltered
Tidal stream strength/Water flow	Very Strong (>6 kn), Strong (3-6 kn), Moderately Strong (1-3 kn), Weak (<1 kn), Very Weak (negligible)	Salinity	Full (30-40 psu)
Habitat Additional Information
Distribution References	Norton, 1970, Norton & Burrows, 1969, Birkett et al., 1998(b), Norton & South, 1969, Hardy & Guiry, 2003
Reproduction/Life History
Reproductive type	Alternation of generations	Developmental mechanism	Spores (sexual / asexual)
Reproductive Season	October to May	Reproductive Location	Insufficient information
Reproductive frequency	Semelparous	Regeneration potential	No
Life span	<1 year	Age at reproductive maturity	<1 year
Generation time	<1 year	Fecundity	Insufficient information
Egg/propagule size	Zoospores ca 5 µm diam.	Fertilization type	External
Larvae/Juveniles Larval/Juvenile dispersal potential 100-1000m Larval settlement period Insufficient information Duration of larval stage <1 day
Additional Information	Saccorhiza polyschides has a typical Laminarian life history in which a macroscopic diploid sporophyte alternates with a microscopic haploid gametophyte. The species is an annual. Sporophytes typically have a life span of less than 10 months. However, plants produced late in the season may over-winter and live for 14-16 months. The base of the lamina, the stipe frills and the bulb are covered in unilocular sporangia, which produce zoospores by meiosis. Each sporangia contains 128 zoospores. The flagellated zoospores are about 5 microns in diameter and possess an eyespot which makes them strongly phototactic. The zoospores may be transported at least 200 m from the parent and they loose their flagella after 24 hrs and settle on the available substrata. 75% of the zoospores settle on the substrata with 24 hours. The zoospores develop into microscopic dioecious gametophytes. Gametophytes take the form of unicellular or filamentous structures. The male gametophytes are more branched than the females and have more numerous, smaller and paler cells. These become fertile in under 10 days in optimal conditions. Male gametophytes release motile sperm that fertilize eggs of female gametophytes, the resultant zygote develops into the new sporophyte.
Reproduction References	Norton, 1970, Norton & Burrows, 1969, Birkett et al., 1998(b)