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Marine Habitat Classification


Description of biotope or habitat type

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   Offshore circalittoral mixed sediment


Habitat (physical) 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

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 SBR.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
Nemertea 3 Abundant 91 81-100 %
Harmothoe 2 Common 78 81-100 %
Pseudomystides limbata 1 24 81-100 %
Eumida sanguinea 2 Abundant 17 81-100 %
Nereiphylla lutea 1 Abundant 51 61-80 %
Glycera lapidum 2 Common 92 81-100 %
Syllis 1 25 81-100 %
Exogone hebes 1 Frequent 23 61-80 %
Sphaerosyllis 1 Frequent 79 61-80 %
Sphaerosyllis bulbosa 1 Frequent 59 61-80 %
Sphaerosyllis tetralix 1 35 81-100 %
Lumbrineris gracilis 2 Common 86 81-100 %
Aonides paucibranchiata 5 Common 241 81-100 %
Laonice bahusiensis 3 Common 60 81-100 %
Polydora caulleryi 2 Frequent 46 81-100 %
Caulleriella zetlandica 1 Common 73 61-80 %
Mediomastus fragilis 4 Frequent 344 81-100 %
Scalibregma inflatum 2 Abundant 136 41-60 %
Polycirrus 2 Common 56 81-100 %
Hydroides norvegica 1 Frequent 24 81-100 %
Grania 1 Common 40 61-80 %
Anoplodactylus petiolatus 1 18 81-100 %
Leptochiton asellus 2 Common 84 81-100 %
Glycymeris glycymeris 1 Abundant 30 61-80 %
Timoclea ovata 2 Common 59 81-100 %
Amphipholis squamata 1 Abundant 203 61-80 %
Polycarpa fibrosa 1 Common 120 41-60 %

Similar biotopes

Not applicable or unknown.


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