Description of biotope or habitat type
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Silted cape-form Laminaria hyperborea on very sheltered infralittoral rock
Physical habitat description
| Salinity | Full (30-35 ppt) |
|---|---|
| Wave exposure | Sheltered, Very sheltered, Extremely sheltered |
| Tidal streams | Weak (>1 kn), Very weak (negligible) |
| Substratum | Bedrock & boulders |
| Zone | Infralittoral - upper |
| Depth Band | 0-5 m, 5-10 m |
| 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
Cape-form of the kelp Laminaria hyperborea on very silted rock, particularly in extremely sheltered sealochs of western Scotland. Below the huge kelp fronds (which often trail onto the seabed) foliose seaweeds form a silted understorey on the rock including Phycodrys rubens, Delesseria sanguinea, Cryptopleura ramosa and Plocamium cartilagineum as well as coralline crusts. At some sites the filamentous red seaweed Bonnemaisonia hamifera, Heterosiphonia plumosa and Vertebrata byssoides may carpet the seabed. Ascidians, particularly Ascidiella aspersa, Ascidia mentula, Ciona intestinalis and Clavelina lepadiformis thrive well in these conditions. The echinoderms Antedon bifida, Echinus esculentus and Asterias rubens are often present along with the gastropod Steromphala cineraria. An abundant growth of the hydroid Obelia geniculata can cover the silted kelp fronds along with the bryozoan Membranipora membranacea. The anthozoan Caryophyllia smithii can be present among the kelp holdfasts. The tube-building polychaete Spirobranchus triqueter can be present on the rock surface along with the crab Necora puber. This biotope generally occurs on shallow bedrock or boulder slopes or isolated rocks protruding through muddy sediment.
Situation
This biotope is often present on rocky outcrops surrounded by muddy sediments (such as VirOphPmax). Deeper, nearby rock, beyond the limit of foliose seaweeds, is often dominated by solitary ascidians (AmenCio).
Temporal variation
Unknown.
Characterising species
| Taxon | Relative importance of taxon for defining this community (%) | Typical abundance - SACFOR scale | % of core records where taxon was recorded |
|---|---|---|---|
| Laminaria hyperborea | 18 | Abundant | 81-100% |
| Ascidia mentula | 6 | Frequent | 81-100% |
| Phycodrys rubens | 5 | Occasional | 61-80% |
| Asterias rubens | 4 | Occasional | 61-80% |
| Clavelina lepadiformis | 4 | Frequent | 61-80% |
| Steromphala cineraria | 4 | Occasional | 61-80% |
| Echinus esculentus | 4 | Occasional | 61-80% |
| Corallinaceae | 3 | Common | 41-60% |
| Antedon bifida | 3 | Occasional | 41-60% |
| Ascidiella aspersa | 3 | Occasional | 41-60% |
| Delesseria sanguinea | 3 | Occasional | 61-80% |
| Spirobranchus triqueter | 3 | Frequent | 61-80% |
| Bonnemaisonia asparagoides | 2 | Occasional | 41-60% |
| Caryophyllia smithii | 2 | Occasional | 41-60% |
| Dictyota dichotoma | 2 | Occasional | 41-60% |
| Obelia geniculata | 2 | Frequent | 41-60% |
| Membranipora membranacea | 1 | Occasional | 21-40% |
| Vertebrata byssoides | 1 | Frequent | 21-40% |
| Ciona intestinalis | 1 | Occasional | 41-60% |
| Cryptopleura ramosa | 1 | Occasional | 21-40% |
| Desmarestia aculeata | 1 | Occasional | 21-40% |
| Heterosiphonia plumosa | 1 | Occasional | 21-40% |
| Necora puber | 1 | Rare | 41-60% |
| Plocamium cartilagineum | 1 | Frequent | 41-60% |
Similar biotopes or habitat types
IR.MIR.KR.Lhyp.Ft
Occurs on moderately exposed rock and supports a dense understorey of foliose red seaweeds beneath the kelp canopy. L. hyperborea is not found in cape-form. A more diverse range of fauna such as sponges and anthozoans are also present in IR.MIR.KR.Lhyp.Ft.
IR.LIR.K.LhypSlat.Ft
S. latissima and L. hyperborea generally occur together in predominantly "sheltered" sites. Large solitary ascidians (Ascidiella spp.) are more prevalent in IIR.LIR.K.LhypCape.