Knotted wrack - Ascophyllum nodosum - General information
Have you seen Ascophyllum nodosum?
If so please submit your record.
| Researched by:
||Jacqueline Hill and Nicola White
|| Refereed by:
||Dr Dagmar Stengel
||Brown and yellow-green seaweeds
| Recorded distribution in Britain and Ireland
||All coasts of Britain and Ireland.
| Habitat information
||The species attaches to rocks and boulders on the middle shore in a range of habitats, from estuaries to relatively exposed coasts. It occupies a similar shore height as Fucus vesiculosus. Subtidal populations have been reported, for example in the very clear waters of Rhode Island, USA. However, an intertidal habit is more usual.
||A common large brown seaweed, dominant on sheltered rocky shores. The species has long strap like fronds with large egg-shaped air bladders at regular intervals. The fronds of Ascophyllum nodosum are typically between 0.5 and 2m in length. The species often bears tufts of the small reddish-brown filamentous epiphytic algae Polysiphonia lanosa. Ascophyllum nodosum occurs on the middle of the shore, often with Fucus vesiculosus. The species grows slowly and plants can live to be several decades old. Individual fronds can become up to 15 years old before breakage.
This review can be cited as follows:
Jacqueline Hill and Nicola White 2008.
Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line].
Plymouth: Marine Biological Association of the United Kingdom.
Available from: <http://www.marlin.ac.uk/speciesfullreview.php?speciesID=2632>