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Marine Habitat Classification


Description of biotope or habitat type

To understand more about what this page is describing, see How to use the classification. See also How to cite.

   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
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.

Distribution of habitat SS.SMx.OMx Offshore circalittoral mixed sediment

  • 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

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