Biodiversity & Conservation

Maerl - Lithothamnion corallioides

Lithothamnion corallioides

Image Christine Maggs - Lithothamnion corallioides. Collected from c. 10m depth. Scale bar is 1 cm.
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Distribution map

Lithothamnion corallioides recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

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  • EC_Habitats
  • UK_BAP
Taxonomy icon Taxonomy Taxon English term
Phylum Rhodophyta Red seaweeds
Class Florideophyceae
Authority (P. & H. Crouan) P. & H. Crouan, 1867
Recent synonyms None
Map icon Recorded Distribution in Britain and Ireland Patchily distributed along the exposed western coasts of the southern British Isles. Locations include the west and south-west of Ireland, the south-west corner of Wales and a few sites off the south coast of England.
Habitat information icon Habitat information Typically found at less than 20 m depth on sand, mud or gravel substrata in areas that are protected from strong wave action but have moderate to high water flow. Usually found as unattached plants forming beds of coralline algal gravel (maerl) in the sublittoral and occasionally lower littoral. The crustose form is very rare in the British Isles. Typically found together with Phymatolithon calcareum.
Text page icon Description An unattached, fragile, alga with a calcareous skeleton. It is very similar to and often confused with Phymatolithon calcareum. Its form is very variable but it commonly occurs as highly branched nodules forming a 3-D lattice. Individual plants may reach 4 - 5 cm across and are bright pink in colour when alive but white when dead.
Identifying features
  • Unattached, un-jointed coralline algae.
  • Bright pink in colour when live, grey white when dead.
  • Often complex lattice with branches typically less than 1 mm in diameter.
  • Very brittle.
  • Branches covered in low mounds.
  • Surface slightly glossy.
Additional information icon Additional information Maerl is a generic name for certain coralline algae that grow unattached on the sea bed. Only two instances of the crustose form of Lithothamnion corallioides have been recorded from the British Isles; in Dorset and Devon.

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This review can be cited as follows:

Angus Jackson 2007. Lithothamnion corallioides. Maerl. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 09/02/2010]. Available from: <http://www.marlin.ac.uk/speciesinformation.php?speciesID=3710>