2. Données et outils
  3. Rechercher un habitat
  4. MC1-2312 - Population dense d'ophiures avec population clairsemée de Ascidia mentula et Ciona intestinalis sur substrat hétérogène abrité du circalittoral en Atlantique
  5. Description
MC1-2312 - Population dense d'ophiures avec population clairsemée de Ascidia mentula et Ciona intestinalis sur substrat hétérogène abrité du circalittoral en Atlantique

Dense brittlestars with sparse Ascidia mentula and Ciona intestinalis on sheltered Atlantic circalittoral mixed substrata
MC1-2311 - Ascidies solitaires, dont Ascidia mentula et Ciona intestinalis, avec Antedon spp. sur roche du circalittoral abritée des vagues en Atlantique

Classification des habitats EUNIS 2022

Descriptif de l'habitat

This biotope is typically found on wave-sheltered sites (although it may be found in wave-exposed through to extremely wave-sheltered conditions), on circalittoral mixed substrata (Bedrock, boulders, cobbles, pebbles and gravel), subject to moderately strong to weak tidal streams. This biotope often has a silty appearance in parallel with MC1-2311 but is characterised by a dense carpet of brittlestars (Ophiothrix fragilis, Ophiocomina nigra and to a lesser extent Ophiura albida) which virtually cover the seabed. Where the underlying substratum is visible, pink coralline crusts and the white calcareous tubes of the keelworm Pomatoceros triqueter are often observed. Hydroids and bryozoans are scarce, perhaps partly due to the smothering effect of the brittlestars and possibly due to the grazing pressure of the sea urchin Echinus esculentus which is occasionally recorded. Other echinoderms present include Asterias rubens and Crossaster papposus. The solitary ascidian Ciona intestinalis may be seen attached to isolated rocks and boulders, whilst on the tops and sides of larger boulders, dead man's fingers Alcyonium digitatum may be recorded. The hermit crab Pagurus bernhardus is often recorded, whilst under boulders and in crevices the claws belonging to the long-clawed squat lobster Munida rugosa may be seen.
Situation: MC1-2312 is found in predominantly sheltered areas, so in the infralittoral zone above, kelp forest formed by dense Laminaria saccharina and cape-form Laminaria hyperborea are frequently recorded. A dense understorey of red algae is also present.

Bibliographie

European Topic Centre on Biological Diversity 2022. EUNIS marine habitat classification 2022 including crosswalks. Table Excel. (Source)