MACOI - Portuguese Seaweeds Website

Class:

Phaeophyceae

Genus:

Sargassum C. Agardh

Species:

Sargassum muticum

Authority:

(Yendo) Fensholt

Description:

Sargassum muticum is a large brown seaweed, varying in colour from dark brown to pale, yellowish brown depending on the season and the growing conditions. S. muticum has regularly alternating lateral shoots or branches, on a central perennial stem. It attaches to the substrate with a disc-shaped holdfast. It has numerous small 2–3 mm round or pear-shaped air-bladders which sit on small stems and cause the alga to stand upright in the water or float if parts of the alga are detached from the basal stem. S. muticum has a frond which may be 75–120 cm long in its native range, but normally reaches a length of 1.5–2 m in Swedish waters, 6–7 m in French waters, and up to 8.5 m in Norwegian waters. Lateral branches detach in the summer or autumn, leaving a short perennial basal stem to overwinter (Wallentinus 1999). During the summer, cigar-shaped reproductive receptacles develop in the areas where the annual shoot or “branch” attaches to the stem, but may also sit on top of the branch.

Link for Algae Handbook (Pereira, 2010).

Name History

Adjective (Latin), without a point, awnless, blunt (Stearn 1973).

Biogeography

Highly invasive: originally from Japan, it now colonizes large parts of the NE Atlantic (Norway to Portugal, North Sea), the W Mediterranean, and the northen Pacific: NW Pacific (Japan), NE Pacific (Alaska to Mexico).

Life Cycle

Sargassum muticum is monoecious and self-fertile. Reproduction occurs in spring, summer and early autumn depending on water temperature. Cigar-shaped reproductive receptacles which produce both eggs and spermatozoids are formed on top of the branches or where the branches attach to the stem. After fertilization, the embryos or germlings detach from the receptacles and reattach to any available hard surface. As germlings settle only a few meters from the mother alga, S. muticum is dependent on drifting with water currents for spread. S. muticum does not reproduce vegetatively (Wallentinus 1999, 2005).

Uses and compounds

Provide biological, medical and pharmacological activity: lowering of cholesterol. Contains: sterols

Source of hydrocolloids - source of laminaran

References

Braune, W. (2008). Meeresalgen. Ein Farbbildführer zu den verbreiteten benthischen Grün- Braun- und Rotalgen der Weltmeere. pp. [1]-596, 266 pls. Ruggell: A.R.G. Gantner Verlag.

Cho, G.Y, Rousseau, F., Reviers, B. de & Boo, S.M. (2006). Phylogenetic relationships within the Fucales (Phaeophyceae) assessed by the photosystem I coding psaA sequences. Phycologia 45: 512-519.

Connan, S., Delisle, F., Deslandes, E. & Gall, E.A. (2006). Intra-thallus phlorotannin content and antioxidant activity in Phaeophyceae of temperate waters. Botanica Marina 49: 39-46.

Farnham, W.F., Fletcher, R.L. & Irvine, L.M. (1973). Attached Sargassum found in Britain. Nature, London 243: 231-232.

Kilar, J.A., Hanisak, M.D. & Yoshida, T. (1992). On the expression of phenotypic variability: why is Sargassum so taxonomically difficult?. In: Taxonomy of Economic Seaweeds with reference to Pacific and Western Atlantic species. (Abbott, I.A. Eds) Vol.3, pp. 95-117. La Jolla, California: California Sea Grant College.

Lee, K. & Yoo, S.-A. (1992). Korean species of Sargassum subgenus Bactrophycus J. Agardh (Sargassaceae, Fucales). In: Taxonomy of Economic Seaweeds. (Abbott, I.A. Eds) Vol.3, pp. 139-147. La Jolla, California: California Sea Grant College.

Lindeberg, M.R. & Lindstrom, S.C. (2010). Field guide to the seaweeds of Alaska. pp. [i-]iii-iv, 1-188, numerous col. photographs. Fairbanks: Alaska Sea Grant College Program.

Loiseaux-de Goër, S. & Noailles, M.-C. (2008). Algues de Roscoff. pp. [1]-215, col. figs. Roscoff: Editions de la Station Biologique de Roscoff.

Pedroche, P.F., Silva, P.C., Aguilar Rosas, L.E., Dreckmann, K.M. & Aguilar Rosas, R. (2008). Catálogo de las algas benthónicas del Pacífico de México II. Phaeophycota. pp. [i-viii], i-vi, 15-146. Mexicali & Berkeley: Universidad Autónoma Metropolitana and University of California Berkeley.

Phillips, N. (1995). Biogeography of Sargassum (Phaeophyta) in the Pacific basin. In: Taxonomy of Economic Seaweeds. (Abbott, I.A. Eds) Vol.5, pp. 107-145. La Jolla, California: California Sea Grant College System.

Schories, D., Selig, U. & Schubert, H. (2009). Species and synonym list of the German marine macroalgae based on historical and recent records. Rostock. Meeresbiolog. Beitr. 21: 7-135.

Stiger, V., Horiguchi, T., Yoshida, T., Coleman, A.W. & Masuda, M. (2003). Phylogenetic relationships within the genus Sargassum (Fucales, Phaeophyceae), inferred from it ITS nrDNA, with an emphasis on the taxonomic revision of the genus. Phycological Research 51(1): 1-10.

Tseng, C.K., Yoshida, T. & Chiang, Y.M. (1985). East Asiatic species of Sargassum subgenus Bactrophycus J.Agardh (Sargassaceae, Fucales), with keys to the sections and species. In: Taxonomy of Economic Seaweeds with reference to some Pacific and Caribbean species. (Abbott, I.A. & Norris, J.N. Eds) Vol.I, pp. 1-14. California Sea Grant Program.

Varela-Alvarez, E., Andreakis, N., Lago-Leston, A., Pearson, G.A., Serrao, E.A., Procaccini, G., Duarte, C.M. & Marba, N. (2006). Genomic DNA isolation from green and brown algae (Caulerpales and Fucales) for microsatellite library construction (Note). Journal of Phycology 42: 741-745.

Yoshida, T., Stiger, V. & Horiguchi, T. (2000). Sargassum boreale sp. nov. (Fucales, Phaeophyceae) from Hokkaido, Japan. Phycological Research 48: 125-132.

Habitat:

In the intertidal and to below the tidal mark (3-5 m)

Common names:

Sargaço japonês (PT), Japanese seaweed, Japanese brown alga, Japweed, Wire weed, Strangle weed (GB), Japanischer Beerentang (DE), Butblæret Sargassotang (DK), Sargassolevä (FI), Japansk drivtang (NO), Sargassosnärja (SE).

Type information:

Basionym: Sargassum kjellmanianum f. muticum Yendo

Lectotype locality: Takashima, Hokkaido, Japan (Yoshida 1978: 122).