Description of biotope or habitat type
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Phymatolithon calcareum maerl beds with red seaweeds in shallow infralittoral clean gravel or coarse sand
Physical habitat description
| Salinity | Full (30-35 ppt) |
|---|---|
| Wave exposure | Moderately exposed, Sheltered, Very sheltered |
| Tidal streams | Moderately strong (1-3 kn), Weak (>1 kn), Very weak (negligible) |
| Substratum | Maerl gravel; coarse sand |
| Zone | Infralittoral - upper, Infralittoral |
| Depth Band | 0-5 m, 5-10 m, 10-20 m |
| Other Features |
Biotope origin
| Derived using data from | Various |
| Faunal group | Epifauna |
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
Upper infralittoral maerl beds characterised by Phymatolithon calcareum in gravels and sand with a wide variety of associated red seaweeds. These algae typically include Dictyota dichotoma, Plocamium cartilagineum, Phycodrys rubens, Chondrus crispus, Halarachnion ligulatum, Chylocladia verticillata, Hypoglossum hypoglossoides and Nitophyllum punctum. These species are not restricted to maerl beds but their abundance on maerl beds differentiates this biotope from SS.SMp.Mrl.Pcal.Nmix. Anthozoans and echinoderms are much less common in this biotope than in SS.SMp.Mrl.Pcal.Nmix, which typically occurs deeper than SS.SMp.Mrl.Pcal.R.
Situation
No situation data available.
Temporal variation
No temporal data available.
Characterising species
| Taxon | Relative importance of taxon for defining this community (%) | Typical abundance - SACFOR scale | % of core records where taxon was recorded |
|---|---|---|---|
| Phymatolithon calcareum | 16 | Abundant | 81-100% |
| Asterias rubens | 6 | Occasional | 81-100% |
| Saccharina latissima | 6 | Frequent | 61-80% |
| Pagurus bernhardus | 5 | Frequent | 61-80% |
| Dictyota dichotoma | 4 | Occasional | 61-80% |
| Steromphala cineraria | 3 | Occasional | 41-60% |
| Plocamium cartilagineum | 3 | Frequent | 61-80% |
| Vertebrata byssoides | 2 | Occasional | 41-60% |
| Cerianthus lloydii | 2 | Frequent | 41-60% |
| Desmarestia aculeata | 2 | Occasional | 41-60% |
| Desmarestia viridis | 2 | Occasional | 41-60% |
| Liocarcinus depurator | 2 | Occasional | 41-60% |
| Nitophyllum punctatum | 2 | Occasional | 41-60% |
| Phycodrys rubens | 2 | Occasional | 41-60% |
| Spirobranchus triqueter | 2 | Occasional | 41-60% |
| Ulva | 2 | Occasional | 41-60% |
| Bonnemaisonia asparagoides | 1 | Occasional | 21-40% |
| Chaetopterus variopedatus | 1 | Occasional | 41-60% |
| Chorda filum | 1 | Frequent | 21-40% |
| Cystoclonium purpureum | 1 | Occasional | 21-40% |
| Lanice conchilega | 1 | Occasional | 21-40% |
| Lomentaria clavellosa | 1 | Occasional | 41-60% |
| Bonnemaisonia hamifera | 1 | Frequent | 21-40% |
| Echinus esculentus | 1 | Occasional | 41-60% |
Similar biotopes or habitat types
SS.SMp.Mrl.Pcal.Nmix
SS.SMp.Mrl.Pcal.R is similar but shallower with more red seaweeds.Classification history of this biotope or habitat type
| Classification version | Code | Habitat name |
|---|---|---|
| 2004 (04.05) | SS.SMp.Mrl.Pcal.R | Phymatolithon calcareum maerl beds with red seaweeds in shallow infralittoral clean gravel or coarse sand |
| 1997 (97.06) | SS.IGS.Mrl.Phy.R | Phymatolithon calcareum maerl beds with red seaweeds in shallow infralittoral clean gravel or coarse sand |