Description of biotope or habitat type
To understand more about what this page is describing, see How to use the classification. See also How to cite.
Polydora sp. tubes on moderately exposed sublittoral soft rock
Physical habitat description
| Salinity | Full (30-35 ppt), Variable (18-35 ppt) |
|---|---|
| Wave exposure | Moderately exposed |
| Tidal streams | Strong (3-6 kn), Moderately strong (1-3 kn), Weak (>1 kn) |
| Substratum | Bedrock (soft) |
| Zone | Circalittoral, Infralittoral |
| Depth Band | 0-5 m, 5-10 m, 10-20 m, Lower shore |
| Other Features |
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
Large patches of chalk and soft limestone are occasionally covered entirely by Polydora sp. tubes to the exclusion of almost all other species. This tends to occur in highly turbid conditions and spans the infralittoral and circalittoral in limestone areas such as the Great and Little Ormes (North Wales) and Gower (South Wales). It is even present on the lower shore in the Severn estuary. The boring form of the sponge Cliona celata often riddles the surface layer of the stone. Other sponges present include Halichondria panicea, Haliclona oculata and Hymeniacidon perlevis. Polydora sp. also frequently occurs in small patches as part of other biotopes (e.g. FluCoAs). Other species present include Alcyonium digitatum, Rolandia coralloides, the hydroids Halecium halecinum, Abietinaria abietina and Tubularia indivisa, the ascidians Clavelina lepadiformis, Botryllus schlosseri and Morchellium argus, the anemones Urticina felina, Metridium senile and Cylista elegans and the bryozoans Flustra foliacea and a crisiid turf. The starfish Asterias rubens, the crabs Inachus phalangium and Carcinus maenas, the polychaete Spirobranchus triqueter, the barnacle Balanus crenatus and the brittlestar Ophiothrix fragilis may also be seen. Please note: this biotope may extend into the infralittoral and littoral zone in areas where water turbidity is sufficiently high.
Situation
No situation data available.
Temporal variation
Not known.
Characterising species
| Taxon | Relative importance of taxon for defining this community (%) | Typical abundance - SACFOR scale | % of core records where taxon was recorded |
|---|---|---|---|
| Polydora | 25 | Abundant | 81-100% |
| Alcyonium digitatum | 8 | Common | 61-80% |
| Urticina felina | 6 | Occasional | 61-80% |
| Halecium halecinum | 5 | Frequent | 41-60% |
| Asterias rubens | 4 | Frequent | 41-60% |
| Flustra foliacea | 4 | Frequent | 41-60% |
| Clavelina lepadiformis | 3 | Occasional | 61-80% |
| Halichondria panicea | 3 | Frequent | 41-60% |
| Botryllus schlosseri | 2 | Occasional | 41-60% |
| Haliclona oculata | 2 | Occasional | 61-80% |
| Inachus phalangium | 2 | Occasional | 41-60% |
| Metridium senile | 2 | Frequent | 41-60% |
| Morchellium argus | 2 | Frequent | 41-60% |
| Ophiothrix fragilis | 2 | Occasional | 41-60% |
| Rolandia coralloides | 2 | Common | 41-60% |
| Abietinaria abietina | 1 | Frequent | 21-40% |
| Balanus crenatus | 1 | Frequent | 21-40% |
| Carcinus maenas | 1 | Frequent | 21-40% |
| Cliona celata | 1 | Occasional | 61-80% |
| Crisiidae | 1 | Common | 21-40% |
| Hymeniacidon perlevis | 1 | Occasional | 41-60% |
| Spirobranchus triqueter | 1 | Occasional | 41-60% |
| Cylista elegans | 1 | Frequent | 41-60% |
| Tubularia indivisa | 1 | Frequent | 21-40% |
Similar biotopes or habitat types
Not applicable or unknown.
Classification history of this biotope or habitat type
| Classification version | Code |
|---|---|
| 1997 (97.06) | CR.MCR.SfR.Pol |
