Knotted wrack
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| Ascophyllum nodosum (L.) Le Jolis |
Knotted wrack or Egg wrack (Ascophyllum nodosum (Linnaeus) Le Jolis) is a large, common, brown alga, in the Phaeophyceae, an edible seaweed of the northern Atlantic Ocean. It is a common species on the north-western coast of Europe (from Spitzbergen to Portugal) including east Greenland, and the north-eastern coast of North America.
Ascophyllum is very popular amongst the science community and has been claimed to be both the most active seaweed on the planet as well as the most researched by the academic community.[1]
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[edit] Description
Ascophyllum nodosum has long fronds with large egg-shaped bladders at regular intervals along the fronds. These fronds can reach up to 2 m in length and are attached to rocks and boulders by what is called a holdfast, algae do not have roots, and the holdfast does not penetrate the rock surface. The fronds are olive-brown in colour and somewhat compressed. This seaweed grows quite slowly and can live for several decades; it may take approximately five years before becoming fertile.
The species is found in a range of coastal habitats from sheltered estuaries to moderately exposed coasts, it often dominates the inter-tidal zone (although sub-tidal populations are known to exist in very clear waters).
There are free floating ecads of this species such as Ascophyllum nodosum mackaii Cotton, which is found at very sheltered locations, such as at the heads of Scottish sea lochs and Ireland.[2]
It has been recorded as an accidental introduction to San Francisco, California, and eradicated as a potential invasive species there.[3]
[edit] Notable Compounds
Ascophyllum nodosum is harvested for use in alginates, fertilisers and for the manufacture of seaweed meal for animal and human consumption. It has long been used as an organic and mainstream fertilizer for many varieties of crops due to its combination of both macronutrient, (eg. N, P, K, Ca, Mg, S) and micronutrients (eg. Mn, Cu, Fe, Zn, etc.) It also host to cytokinins, auxin-like, gibberellins, betaines, mannitol, organic acids, polysaccharides, amino acids, and proteins which are all very beneficial and widely used in agriculture. .[4]
[edit] References
- ^ Senn, T.L. 1987. “Seaweed and Plant Growth” Library of Congress #87-90524; ISBN 0-939241-01-3
- ^ Gibb, D.C. 1957. The free-living forms of Ascophyllum nodosum (L.) Le Jol. J. Ecol., 45: 49 - 83
- ^ Miller, A.W., Chang, A.L., Cosentino-Manning, N and Ruiz, G.M. 2004. A new record and eradication of the north Atlantic alga Ascophyllum nodosum (Phaeophyceae) from San Francisco Bay, California, USA. J. Phycol. 40: 1028 - 1031
- ^ Norrie, J., and Hiltz, D.A., 1999. Seaweed Extract Research and Applications in Agriculture (Agro food Industry hi-tech March/April 1999)
