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Rockweed

Fucus distichus

Summary 7

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 8

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Fucus distichusPacific rockweed, Olympic National Park, USA.jpgTaxonomíaReino: ProtistaFilo: HeterokontophytaClase: PhaeophyceaeOrden: FucalesFamilia: FucaceaeGénero: FucusEspecie: F. 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.[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.

Referencias[editar]

  1. ↑G. Russell (1978). D. E. G. Irvine & J. H. Price, ed. Modern Approaches to the Taxonomy of Red and Brown Algae. Systematics Association. pp. 339-369.
  2. ↑ abH. T. Powell (1957). «Studies in the genus Fucus L. II. Distribution and ecology of forms of Fucus distichus L. emend. Powell in Britain and Ireland». Journal of the Marine Biology Association of the United Kingdom36: 663-693.
  3. ↑H. T. Powell (1957). «Studies in the genus Fucus L. I. Fucus distichus L. emend. Powell». Journal of the Marine Biology Association of the United Kingdom36: 407-432.
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Fucus distichus L. subsp. edentatus (Bach.Pyl.) Powell, isotypo espécimen de herbario, 1910
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Fucus distichus 9

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Fucus distichus L. subsp. edentatus (Bach.Pyl.) Powell, isotype herbarium specimen, 1910
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.

Description

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 are 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]

Distribution

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]

Biology

Like other brown algae, there is an alternation of haploid and diploid generations. The haploidthalli form isogamous, anisogamous or oogamousgametes 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]

References

  1. ^ abcM. D. Guiry (2011). Guiry MD, Guiry GM, eds. "Fucus distichus Linnaeus, 1767". AlgaeBase. National University of Ireland, Galway. World Register of Marine Species. Retrieved April 24, 2012..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"""""'"'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
  2. ^ abBunker, F.StP.D., Maggs, C.A., Brodie, J.A. and Bunker, A.R. 2017. Seaweeds of Britain and Ireland. Second Edition. Wild Nature Press, Plymouth, UK ISBN978-0-9955673-3-7
  3. ^ abcNicola White (2007). "A brown seaweed - Fucus distichus - General information". Marine Life Information Network. Marine Biological Association of the United Kingdom. Retrieved April 24, 2012.
  4. ^ abc"Fucus distichus (Silva)". Race Rocks Digital Herbarium. Race Rocks Ecological Reserve/Marine Protected Area. December 4, 2002. Retrieved April 24, 2012.
  5. ^N. L. Bird & J. McLachlan (1976). "Control of formation of receptacles in Fucus distichus L. subsp. distichus (Phaeophyceae, Fucales)". Phycologia. 15 (1): 79–84. doi:10.2216/i0031-8884-15-1-79.1.
  6. ^E. L. Rice & A. R. O. Chapman (1985). "A numerical taxonomic study of Fucus distichus (Phaeophyta)". Journal of the Marine Biological Association of the United Kingdom. 65 (2): 433–459. doi:10.1017/S0025315400050530.
  7. ^ abGareth A. Pearson & Susan H. Brawley (1996). "Reproductive ecology of Fucus distichus (Phaeophyceae): an intertidal alga with successful external fertilization"(PDF). Marine Ecology Progress Series. 143 (1–3): 211–233. doi:10.3354/meps143211.
  8. ^Christopher W. McKindsey & Edwin Bourget (2001). "Diversity of a northern rocky intertidal community: the influence of body size and succession". Ecology. 82 (12): 3462–3478. doi:10.1890/0012-9658(2001)082[3462:DOANRI]2.0.CO;2.
  9. ^"Fucus distichus". Seattle Seawall Habitat Enhancement Project. Retrieved April 24, 2012.
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Sources and Credits

  1. (c) jengordon, some rights reserved (CC BY-NC), uploaded by jengordon
  2. (c) anonymous, some rights reserved (CC BY-NC-SA), https://eol.org/media/8807032
  3. (c) anonymous, some rights reserved (CC BY-NC-SA), https://eol.org/media/8807028
  4. (c) anonymous, some rights reserved (CC BY-NC-SA), https://eol.org/media/8807030
  5. anonymous, no known copyright restrictions (public domain), https://eol.org/media/7584301
  6. anonymous, no known copyright restrictions (public domain), https://eol.org/media/7584302
  7. (c) Wikipedia, some rights reserved (CC BY-SA), https://en.wikipedia.org/wiki/Fucus_distichus
  8. (c) Autores y editores de Wikipedia, some rights reserved (CC BY-SA), http://eol.org/data_objects/12555788
  9. (c) Wikipedia authors and editors, some rights reserved (CC BY-SA), http://eol.org/data_objects/13189072

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