Fucus distichus or rockweed is a species of brown alga in the family Fucaceae to be found in the intertidal zones of rocky seashores in the Northern Hemisphere, mostly in rock pools.
This is a small tufted brown alga. The fronds are rarely more than 4 mm wide[2] narrow and grow up to thirty centimetres long. They do not include airbladders as in some other species of Fucus.[3] The fronds are fairly rigid and cartilaginous, partially flattened, and olive green to yellowish green in colour. The plant is branched and has a basal discoid holdfast. The midrib is conspicuous and near the holdfast the stalk is narrowed because of the thickening of the midrib and the erosion of the margins. The apices of the frond are rounded and the swollen receptacles at the tips are yellowish and up to six centimetres long.[4]
Two sub-species have been recorded from Great Britain and Ireland: F. distichus ssp. anceps and F. distichus ssp. edentates, each with a distinctive form.[2]
The brown colour is due to the xanthophyll, fucoxanthin which masks the colour of the other pigments, beta-carotene, chlorophyll a and c and other xanthophylls.[1] Fucus distichus has a high content of phlorotannins which may protect larger plants from grazing by periwinkles though young plants are susceptible.[3]
In Great Britain, rockweed is found on northern coasts of Scotland and the north and west coasts of Ireland where it is found on rock faces and in rock pools in the upper littoral zone. It also occurs on the eastern coast of North America[3] and on the west coast from Alaska to California.[4]
Like other brown algae, there is an alternation of haploid and diploid generations. The haploid thalli form isogamous, anisogamous or oogamous gametes and the diploid thalli form zoospores by meiosis.[1] Reproduction is seasonal, and receptacles start being formed in late autumn in response to short days.[5] The gametes are of both sexes and when released, ova can survive and disperse for several days. It is thought that self-fertilisation often occurs in this species and once a zygote is formed it can only be dispersed over a limited distance.[6] The plant dies back after reproducing and gets washed from its rock substrate by waves during the following winter.[4]
A study was undertaken to see what factors influenced natural gamete release and the rate of fertilisation success in Fucus distichus. The study sites were rock pools on the coast of Maine.[7] It was found that the release and settlement of eggs and zygotes occurred during daytime low tide periods, particularly when these fell between 10am and 2pm. Few gametes were released during the night time low tide period nor during the daytime period around noon when there was not a low tide. There was no correlation between the temperature or salinity of the water and gamete release and only a weak association with the lunar phase, few gametes being released around the times of full and new moons. The study showed that fertilisation was successful and in the range 80% to 100% in F. distichus due to the avoidance of gamete release when the water velocity is high under the turbulent conditions of high tide.[7]
It has been found that this species grows more abundantly on sloped than on vertical rock faces. Its presence increases species richness as it forms canopies in the mid to high intertidal zone that provide protection, shelter and food for a variety of small invertebrates including many gastropods and crustaceans.[8][9]
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Fucus distichus L. subsp. edentatus (Bach.Pyl.) Powell, isotype herbarium specimen, 1910 Fucus distichus (rockweed) washed up at the high tide line at Morecambe Bay, along with other debris. Fucus distichus or rockweed is a species of brown alga in the family Fucaceae to be found in the intertidal zones of rocky seashores in the Northern Hemisphere, mostly in rock pools.
Fucus distichus es una especie de alga parda (Phaeophyceae), que vive en el litoral de la costa norte de los océanos Atlántico y Pacífico. Crece hasta unos 10-30 cm de largo con un corto estipe cilíndrico con ramificación dicótomica, plana y con un nervio central.[1] En las Islas Británicas se han descrito dos especies.[2] F. distichus subsp. edentatus fue descrita por primera vez en las Islas Shetland por Börgesen en 1903, mientras que F. Powell describió F. distichus subsp. anceps en la costa norte de Escocia. También se encuentra en la costa Norte y Oeste de Irlanda.[2][3] En el Océano Pacífico se extiende desde Alaska a California.
F. distichus es un organismo que se utiliza como modelo para estudiar el desarrollo de la polaridad celular, ya que forma un zigoto apolar que puede desarrollar polaridad dado un número variable de gradientes.
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Especies: Fucus distichus
Fucus distichus es una especie de alga parda (Phaeophyceae), que vive en el litoral de la costa norte de los océanos Atlántico y Pacífico. Crece hasta unos 10-30 cm de largo con un corto estipe cilíndrico con ramificación dicótomica, plana y con un nervio central. En las Islas Británicas se han descrito dos especies. F. distichus subsp. edentatus fue descrita por primera vez en las Islas Shetland por Börgesen en 1903, mientras que F. Powell describió F. distichus subsp. anceps en la costa norte de Escocia. También se encuentra en la costa Norte y Oeste de Irlanda. En el Océano Pacífico se extiende desde Alaska a California.
F. distichus es un organismo que se utiliza como modelo para estudiar el desarrollo de la polaridad celular, ya que forma un zigoto apolar que puede desarrollar polaridad dado un número variable de gradientes.
Fucus distichus est une espèce d'algues brunes marines de la famille des Fucaceae. Elle vit dans l'océan Pacifique nord et nord-ouest et en mer de Béring.
Selon AlgaeBase (7 juil. 2012)[4] :
Selon NCBI (7 juil. 2012)[5] :
Selon World Register of Marine Species (8 juillet 2018)[6] :
Fucus distichus est une espèce d'algues brunes marines de la famille des Fucaceae. Elle vit dans l'océan Pacifique nord et nord-ouest et en mer de Béring.
Fucus distichus é uma espécie de alga castanha (Phaeophyceae), que ocorre no litoral das costas do hemisfério norte dos oceanos Atlântico e Pacífico. Cresce até 10–30 cm de comprimento, com um curto estipe cilíndrico com ramificação dicótomica plana e com uma nervura central bem marcada.[1]
Para as ilhas Britânicas estão descritas duas subespécies:[2] (1) F. distichus subsp. edentatus, descrita pela primeira vez nas Shetland por Frederik Børgesen em 1903; e (2) F. distichus subsp. anceps, descrita por F. Powell na costa norte da Escócia, mas que também ocorre na costa norte e oeste da Irlanda.[2][3]
No Oceano Pacífico a espécie ocorre desde o Alaska à Califórnia.
F. distichus é um organismo que se utiliza como modelo para estudar o desenvolvimento da polaridade celular, pois forma um zigoto apolar que pode desenvolver polaridade em função de um número variável de gradientes.
Fucus distichus é uma espécie de alga castanha (Phaeophyceae), que ocorre no litoral das costas do hemisfério norte dos oceanos Atlântico e Pacífico. Cresce até 10–30 cm de comprimento, com um curto estipe cilíndrico com ramificação dicótomica plana e com uma nervura central bem marcada.
_Powell_-_Fucaceae_-_Plant_type_specimen.jpeg)
_Powell_-_Fucaceae_-_Plant_type_specimen.jpeg)
_Powell_-_Fucaceae_-_Plant_type_specimen.jpeg)
