Oarweed (Laminaria digitata), also known as 'tangle' or 'tangleweed' is a familiar glossy golden brown kelp, which grows attached to rocky substrates with a dome-shaped cluster of root-like holdfasts (3). The smooth and flexible stipe (stem) is oval in cross-section, and gives rise to a broad frond that is divided into ribbon-like segments and lacks a midrib (2).
This perennial species lives for 4-6 years (2). New growth occurs at the base of the stipe, where it joins to the frond; although growth occurs throughout the year, it seems to be fastest during the spring (3).Kelp beds are important habitats for many other species (2).
Kelps have been used by humans as a source of chemicals, as agricultural fertilisers, and for culinary uses (2).
Occurs around the coasts of Britain, but is scarce along parts of the east coast due to a lack of hard substrates and turbidity of the water (2). Elsewhere it is known from the Atlantic coasts of Europe, as well as from Iceland, southern Greenland and the eastern coasts of North America (2).
This kelp is characteristic of the lower intertidal and shallow subtidal zones (4), and can reach a depth of 20m in clear water (2). It seems to fare particularly well in moderately exposed areas or where there are strong water currents (2).
Hill, J.M., 2000. Laminaria digitata. Oarweed. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. (August, 2002) http://www.marlin.ac.uk/species/Laminariadigitata.htm
Fish, J.D. and Fish, S. (1996) A student's guide to the seashore. Second Edition. Cambridge University Press, Cambridge.
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