Description of biotope or habitat type
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Sublittoral mixed sediment
Physical habitat description
Salinity | Full (30-35 ppt), Reduced (18-30ppt), Variable (18-35 ppt) |
---|---|
Wave exposure | Moderately exposed, Sheltered, Very sheltered, Extremely sheltered |
Tidal streams | Moderately strong (1-3 kn), Weak (>1 kn), Very weak (negligible) |
Substratum | Mixed sediments. |
Zone | Circalittoral, Infralittoral |
Depth Band | 0-5 m, 5-10 m, 10-20 m, 20-30 m, 30-50 m |
Other Features |
Biotope origin
Derived using data from | Various |
Faunal group | Epifauna/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
Sublittoral mixed (heterogeneous) sediments found from the extreme low water mark to deep offshore circalittoral habitats. These habitats incorporate a range of sediments including heterogeneous muddy gravelly sands and mosaics of cobbles and pebbles embedded in or lying upon sand, gravel or mud. There is a degree of confusion with regard to nomenclature within this complex as many habitats could be defined as containing mixed sediments, in part depending on the scale of the survey and the sampling method employed. The BGS trigon can be used to define truly mixed or heterogeneous sites with surficial sediments which are a mixture of mud, gravel and sand. However, another 'form' of mixed sediment includes mosaic habitats such as superficial waves or ribbons of sand on a gravel bed or areas of lag deposits with cobbles/pebbles embedded in sand or mud and these are less well defined and may overlap into other habitat or biotope complexes. These habitats may support a wide range of infauna and epibiota including polychaetes, bivalves, echinoderms, anemones, hydroids and Bryozoa. Mixed sediments with biogenic reefs or macrophyte dominated communities are classified separately in the SS.SBR and SS.SMp habitat complexes respectively.
Situation
No situation data available.
Temporal variation
No temporal data available.
Characterising species
Characterising species data not applicable.
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 | Sublittoral mixed sediment |
2004 (04.05) | SS.SMx | Sublittoral mixed sediment |
1997 (97.06) | SS.CMX (part) | Circalittoral mixed sediments |
1997 (97.06) | SS.IMX (part) | Infralittoral mixed sediments |