Description of biotope or habitat type
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Offshore circalittoral mixed sediment
Physical habitat description
Salinity | Full (30-35 ppt) |
---|---|
Wave exposure | Moderately exposed, Sheltered |
Tidal streams | |
Substratum | Mud and sandy muddy mixed sediments |
Zone | Circalittoral - lower |
Depth Band | 20-30 m, 30-50 m, 50-100 m, 100-200 m |
Other Features |
Biotope origin
Derived using data from | Various |
Faunal group | Infauna |
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
Offshore (deep) circalittoral habitats with slightly muddy mixed gravelly sand and stones or shell. This habitat may cover large areas of the offshore continental shelf although there is relatively little data available. Such habitats are often highly diverse with a high number of infaunal polychaete and bivalve species. Animal communities in this habitat are closely related to offshore gravels and coarse sands and in some areas populations of the horse mussel Modiolus modiolus may develop in these habitats (see SS.SBR.SMus.ModMx). Only one biotope is currently described under this biotope complex.
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 | Typical abundance - (count per m2) | % of core records where taxon was recorded |
---|---|---|---|---|
Aonides paucibranchiata | 5 | Common | 241 | 81-100% |
Mediomastus fragilis | 4 | Frequent | 344 | 81-100% |
Laonice bahusiensis | 3 | Common | 60 | 81-100% |
Nemertea | 3 | Abundant | 91 | 81-100% |
Eumida sanguinea | 2 | Abundant | 17 | 81-100% |
Glycera lapidum | 2 | Common | 92 | 81-100% |
Harmothoe | 2 | Common | 78 | 81-100% |
Leptochiton asellus | 2 | Common | 84 | 81-100% |
Hilbigneris gracilis | 2 | Common | 86 | 81-100% |
Polycirrus | 2 | Common | 56 | 81-100% |
Dipolydora caulleryi | 2 | Frequent | 46 | 81-100% |
Scalibregma inflatum | 2 | Abundant | 136 | 41-60% |
Timoclea ovata | 2 | Common | 59 | 81-100% |
Amphipholis squamata | 1 | Abundant | 203 | 61-80% |
Anoplodactylus petiolatus | 1 | 18 | 81-100% | |
Chaetozone zetlandica | 1 | Common | 73 | 61-80% |
Parexogone hebes | 1 | Frequent | 23 | 61-80% |
Glycymeris glycymeris | 1 | Abundant | 30 | 61-80% |
Grania | 1 | Common | 40 | 61-80% |
Hydroides norvegica | 1 | Frequent | 24 | 81-100% |
Nereiphylla lutea | 1 | Abundant | 51 | 61-80% |
Polycarpa fibrosa | 1 | Common | 120 | 41-60% |
Pseudomystides limbata | 1 | 24 | 81-100% | |
Sphaerosyllis | 1 | Frequent | 79 | 61-80% |
Sphaerosyllis bulbosa | 1 | Frequent | 59 | 61-80% |
Prosphaerosyllis tetralix | 1 | 35 | 81-100% | |
Syllis | 1 | 25 | 81-100% |
Similar biotopes or habitat types
Not applicable or unknown.
Classification history of this biotope or habitat type
Classification version | Code | Habitat name |
---|---|---|
2015 (15.03) | SS.SMx.OMx | Offshore circalittoral mixed sediment |
2004 (04.05) | SS.SMx.OMx | Offshore circalittoral mixed sediment |
1997 (97.06) | Part of SS.COS | Circalittoral offshore sediments |