Description of biotope or habitat type
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Sponges and anemones on vertical circalittoral bedrock
Physical habitat description
| Salinity | Full (30-35 ppt) |
|---|---|
| Wave exposure | Very exposed, Exposed, Moderately exposed |
| Tidal streams | Strong (3-6 kn), Moderately strong (1-3 kn), Weak (>1 kn), Very weak (negligible) |
| Substratum | Bedrock |
| Zone | Infralittoral - lower, Circalittoral |
| Depth Band | 10-20 m, 20-30 m, 30-50 m |
| Other Features | Vertical rock |
Download comparative physical and biological data. The comparative tables enable a rapid comparison of the species composition and principal physical characteristics between a given set of biotopes.
- Records used to define the biotope (core records)
- Other records assigned to this biotope, marked as 'certain'
- Other records assigned to this biotope, marked as 'uncertain'
- Predicted extent of the level 3 (for sublittoral rock & deep sea) or 4 (for sublittoral sediment) habitat
Point data based on records in the UK Marine Recorder Snapshot. Predicted habitat extent is from UKSeaMap.
Description
This biotope is found on exposed to moderately wave exposed , vertical and overhanging, circalittoral bedrock, subject to strong through to weak tidal streams. This biotope is characterised by a mixed faunal turf of hydroids (Nemertesis antennina, Tubularia indivisa and Halecium halecium) and bryozoans (Alcyonidium diaphanum and crisiid turf). There is frequently a diverse range of sponges recorded, including Cliona celata, Pachymatisma johnstonia, Dysidea fragilis and Hemimycale columella. There may be dense aggregation of dead mans fingers Alcyonium digitatum along with clumps of the cup coral Caryophyllia smithii, and the anthozoans Corynactis viridis, Actinothoe sphyrodeta, Cylista elegans and Metridium senile. Other species present include the echinoderms Echinus esculentus, Asterias rubens, Marthasterias glacialis, Henricia oculata, Holothuria (Panningothuria) forskali and Antedon bifida, clumps of the lightbulb tunicate Clavelina lepadiformis and the top shell Calliostoma zizyphinum. Three regional variations of this biotope have been recorded. The first variant is characterised by a Bugula turf along with the pink sea fan Eunicella verrucosa, and has been recorded from around southwest England and Wales. The second variant, characterised by a dense 'carpet' of Corynactis viridis and Metridium senile has been recorded predominantly from the west coast of Ireland. The final variant is characterised by a very diverse, dense faunal turf of hydroids, bryozoans and ascidians and has been recorded from the coasts around Northern Ireland.
Situation
No situation data available.
Temporal variation
No temporal variation data available.
Characterising species
| Taxon | Relative importance of taxon for defining this community (%) | Typical abundance - SACFOR scale | % of core records where taxon was recorded |
|---|---|---|---|
| Alcyonium digitatum | 10 | Frequent | 81-100% |
| Corynactis viridis | 10 | Frequent | 61-80% |
| Caryophyllia smithii | 9 | Frequent | 81-100% |
| Cliona celata | 5 | Occasional | 61-80% |
| Echinus esculentus | 5 | Occasional | 61-80% |
| Asterias rubens | 4 | Occasional | 61-80% |
| Actinothoe sphyrodeta | 3 | Occasional | 41-60% |
| Marthasterias glacialis | 3 | Occasional | 41-60% |
| Nemertesia antennina | 3 | Occasional | 41-60% |
| Calliostoma zizyphinum | 2 | Occasional | 41-60% |
| Clavelina lepadiformis | 2 | Occasional | 41-60% |
| Dysidea fragilis | 2 | Occasional | 41-60% |
| Henricia oculata | 2 | Occasional | 41-60% |
| Holothuria (Panningothuria) forskali | 2 | Occasional | 21-40% |
| Pachymatisma johnstonia | 2 | Occasional | 41-60% |
| Cylista elegans | 2 | Occasional | 41-60% |
| Tubularia indivisa | 2 | Occasional | 41-60% |
| Alcyonidium diaphanum | 1 | Rare | 21-40% |
| Antedon bifida | 1 | Occasional | 21-40% |
| Crisiidae | 1 | Frequent | 21-40% |
| Halecium halecinum | 1 | Occasional | 21-40% |
| Hemimycale columella | 1 | Occasional | 21-40% |
| Metridium senile | 1 | Occasional | 21-40% |
Similar biotopes or habitat types
Not applicable or unknown.
Classification history of this biotope or habitat type
| Classification version | Code |
|---|---|
| 1995 | LMXD.FCER |