Wrack (seaweed)
Wrack refers to seaweeds and seagrasses cast up on shore.
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Wrack is a term used for several species of seaweed in the family Fucaceae, and more generally for any seaweeds or seagrasses that wash up on beaches and accumulate in the wrack zone. It consists largely of species of Fucus, brown algae with flat branched ribbon-like fronds, and may also include seagrasses such as Zostera marina or Posidonia australis.
Quick Facts
- Seagrass example
- Zostera marina (marine flowering plant with bright green long narrow grass-like leaves)
- Historical uses
- making manure
- and for making 'kelp'
- a form of potash
Facts from the source article.
Background
Historically, wrack was used for making manure and for making 'kelp', a form of potash. The word's origin is possibly from Middle Dutch 'wrak', from its root meaning to push, to shove, to drive. In the case of seaweed, its sense is in a possible derivation of the word wreck — cast up on shore. The term encompasses several named species: bladder wrack (Fucus vesiculosus), channelled wrack (Pelvetia canaliculata), knotted wrack (Ascophyllum nodosum), spiral wrack or flat wrack (Fucus spiralis), and toothed wrack or serrated wrack (Fucus serratus).
These are brown algae with flat branched ribbon-like fronds, with F. serratus characterized by a saw-toothed margin and F. vesiculosus by bearing air-bladders. Another component of sea wrack may be seagrasses such as Zostera marina, a marine flowering plant with bright green long narrow grass-like leaves, and Posidonia australis, which occurs sub-tidally on the southern coasts of Australia and sheds its older ribbon-like leaf blades in winter, resulting in thick accumulations along more sheltered shorelines.
More in Brown Macroalgae and Kelp
Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Wrack (seaweed) (CC BY-SA 4.0).
- Word definitions: the Codexery glossary, each quoted from its Wikipedia article.
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