Biodiversity & Conservation

Corallina officinalis and coralline crusts in shallow eulittoral rockpools.



Image David Connor - Pool in Pelvetia zone Corallina officinalis and coralline crusts (LR.Cor). Image width ca 50 cm.
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Distribution map

LR.LR.Rkp.Cor recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

  • EC_Habitats

Text page icon Habitat description

Map icon Distribution of biotope in Britain and Ireland Found on rocky shores on all coasts of Britain and Ireland.
National importance Not available

Text page icon Description of biotope

For a full description of this biotope including characterizing species, distribution, survey information and references visit JNCC

Shallow rockpools throughout the eulittoral zone may be characterized by a covering of encrusting coralline algae on which Corallina officinalis often forms a dense turf. These 'coralline' pools have a striking appearance as they are dominated predominantly by red algae. Filamentous and foliose red algae found in these pools include Dumontia contorta, Mastocarpus stellatus and Ceramium rubrum [now Ceramium virgatum]. The green algae Cladophora rupestris and Ulva spp. can also occur. The pools may hold large numbers of grazing molluscs, particularly Littorina littorea (which often occurs in exceptionally high densities in upper shore pools), Patella vulgata and Gibbula cineraria. Gastropods may graze these pools to such an extent that they are devoid of any foliose red algae, and are reduced to encrusting coralline algae and large numbers of gastropods. Large brown algae are generally absent (compare with LR.FK), although small Halidrys siliquosa may be present. Within the pools, pits and crevices are often occupied by the anemone Actinia equina and small Mytilus edulis. Similar sized pools in the littoral fringe generally lack the encrusting coralline algae and are characterized by green algae (see LR.G). In Ireland, the sea urchin Paracentrotus lividus can dominate these shallow coralline pools (see LR.Cor.Par - Coralline crusts and Paracentrotus lividus in shallow eulittoral rockpools). In south-west Britain, the brown alga Bifurcaria bifurcata (LR.Cor.Bif - Bifurcaria bifurcata in shallow eulittoral rockpools) or Cystoseira spp. (LR.Cor.Cys - Cystoseira spp. in shallow eulittoral rockpools) can be regionally dominant. (Information taken from the Marine Biotope Classification for Britain and Ireland, Version 97.06: Connor et al., 1997a, b).

Additional information icon Additional information

In the extreme south west of Britain, another coralline algae, Jania rubens, which is similar to Corallina officinalis, may occur in large amounts, almost certainly within this biotope.

This review can be cited as follows:

Budd, G.C. 2002. Corallina officinalis and coralline crusts in shallow eulittoral rockpools.. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 26/11/2015]. Available from: <>