Description of biotope or habitat type
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Infralittoral mixed sediment
Physical habitat description
| Salinity | Full (30-35 ppt), Variable (18-35 ppt) |
|---|---|
| Wave exposure | Moderately exposed, Sheltered, Very sheltered |
| Tidal streams | Strong (3-6 kn), Moderately strong (1-3 kn), Weak (>1 kn) |
| Substratum | Mixed sediment |
| Zone | Infralittoral |
| Depth Band | 0-5 m, 5-10 m, 10-20 m, 20-30 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
Shallow mixed (heterogeneous) sediments in fully marine or near fully marine conditions, supporting various animal-dominated communities, with relatively low proportions of seaweeds. This habitat may include well mixed muddy gravelly sands or very poorly sorted mosaics of shell, cobbles and pebbles embedded in mud, sand or gravel. Due to the quite variable nature of the sediment type, a widely variable array of communities may be found, including those characterised by bivalves (SS.SMx.IMx.VcorAsquAps, SS.SMx.IMx.CreAsAn, and SS.SMx.IMx.Ost), polychaetes (SS.SMx.IMx.SpavSpAn) and file shells (SS.SMx.IMx.Lim). This has resulted in many species being described as characteristic of this biotope complex all contributing only a small percentage to the overall similarity (see below). This biotope complex may also include a newly proposed Chaetopterus biotope (Rees pers com.) recently found in the eastern English Channel. This biotope is characterised by an undescribed Chaetopterus sp. and small Lanice conchilega. Further sampling is need in order to assess and fully characterise this potential biotope. As a result, the Chaetopterus biotope has not been included in this revision. Infaunal data for this biotope complex are limited to that described in the biotope SS.SMx.IMx.VcorAsquAps and so are not representative of the infaunal component of the whole 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 | % of core records where taxon was recorded |
|---|---|---|---|
| Crepidula fornicata | 20 | Common | 41-60% |
| Apseudopsis latreillii | 7 | Common | 81-100% |
| Sabella pavonina | 7 | Common | 21-40% |
| Nematoda | 2 | Frequent | 61-80% |
| Buccinum undatum | 5 | Occasional | 41-60% |
| Calyptraea chinensis | 5 | Common | 81-100% |
| Mediomastus fragilis | 5 | Common | 81-100% |
| Urticina felina | 5 | Occasional | 41-60% |
| Aphelochaeta marioni | 4 | Common | 61-80% |
| Alcyonium digitatum | 3 | Occasional | 21-40% |
| Asterias rubens | 3 | Occasional | 21-40% |
| Monocorophium sextonae | 3 | Common | 61-80% |
| Lanice conchilega | 3 | Occasional | 21-40% |
| Maera grossimana | 3 | Common | 61-80% |
| Melinna palmata | 3 | Abundant | 61-80% |
| Nemertea | 3 | Common | 81-100% |
| Paguridae | 3 | Occasional | 21-40% |
| Pagurus bernhardus | 3 | Occasional | 21-40% |
| Styela clava | 3 | Occasional | 21-40% |
| Syllidia armata | 3 | Common | 61-80% |
| Chaetozone gibber | 3 | Common | 41-60% |
| Amphicteis gunneri | 2 | Abundant | 41-60% |
| Ascidiella aspersa | 2 | Frequent | 21-40% |
| Caulleriella alata | 2 | Common | 41-60% |
| Cerianthus lloydii | 2 | Occasional | 21-40% |
| Amphilectus fucorum | 2 | Occasional | 21-40% |
| Gammarella fucicola | 2 | Frequent | 61-80% |
| Hydrallmania falcata | 2 | Occasional | 21-40% |
| Limaria hians | 2 | Abundant | 21-40% |
| Ophiothrix fragilis | 2 | Occasional | 21-40% |
| Spirobranchus lamarcki | 2 | Common | 41-60% |
| Tellimya ferruginosa | 2 | Frequent | 61-80% |
| Tubificoides benedii | 2 | Common | 61-80% |
| Venerupis corrugata | 2 | Abundant | 81-100% |
| Tubificoides swirencoides | 2 | Common | 41-60% |
| Abludomelita gladiosa | 1 | Frequent | 41-60% |
| Phyllodoce mucosa | 1 | Common | 61-80% |
| Calliostoma zizyphinum | 1 | Rare | 21-40% |
| Cancer pagurus | 1 | Rare | 21-40% |
| Carcinus maenas | 1 | Occasional | 21-40% |
| Hyas araneus | 1 | Occasional | 21-40% |
| Janira maculosa | 1 | Frequent | 61-80% |
| Metaphoxus simplex | 1 | Common | 41-60% |
| Necora puber | 1 | Occasional | 21-40% |
| Notomastus latericeus | 1 | Frequent | 61-80% |
| Spirobranchus triqueter | 1 | Occasional | 21-40% |
| Sphaerosyllis hystrix | 1 | Frequent | 41-60% |
| Ostrea edulis | 1 | Occasional | 1-20% |
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.IMx | Infralittoral mixed sediment |
| 2004 (04.05) | SS.SMx.IMx | Infralittoral mixed sediment |
| 1997 (97.06) | SS.IMX.FaMx | Shallow mixed sediment faunal communities |