MC3-211 - Spirobranchus triqueter (anciennement Pomatoceros triqueter) avec balanes et bryozoaires encroûtants sur galets et cailloutis instables du circalittoral en Atlantique (EUNIS 2022)

MC3-211 - Spirobranchus triqueter (anciennement Pomatoceros triqueter) avec balanes et bryozoaires encroûtants sur galets et cailloutis instables du circalittoral en Atlantique

Pomatoceros triqueter with barnacles and bryozoan crusts on Atlantic circalittoral unstable cobbles and pebbles

MC3-212 - Mediomastus fragilis, Lumbrineris spp. et bivalves vénéridés dans du sable grossier ou du gravier du circalittoral en Atlantique

Classification des habitats EUNIS 2022

Descriptif de l'habitat

This biotope is characterised by a few ubiquitous robust and/or fast growing ephemeral species which are able to colonise pebbles and unstable cobbles and slates which are regularly moved by wave and tidal action. The main cover organisms tend to be restricted to calcareous tube worms such as Pomatoceros triqueter (or P. lamarcki), small barnacles including Balanus crenatus and Balanus balanus, and a few bryozoan and coralline algal crusts. Scour action from the mobile substratum prevents colonisation by more delicate species. Occasionally in tide-swept conditions tufts of hydroids such as Sertularia argentea and Hydrallmania falcata are present. This biotope often grades into MC4-214 which is characterised by large amounts of the above hydroids on stones also covered in Pomatoceros and barnacles. The main difference here is that MC4-214, seems to develop on more stable, consolidated cobbles and pebbles or larger stones set in sediment in moderate tides. These stones may be disturbed in the winter and therefore long-lived and fragile species are not found.
Situation: This biotope is found on exposed open coasts as well as at the entrance to marine inlets.

Bibliography

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