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Marine Habitat Classification

Description of biotope or habitat type

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   Laminaria saccharina and red seaweeds on infralittoral sediments

Physical habitat description

Salinity Full (30-35 ppt)
Wave exposure Exposed, Moderately exposed, Sheltered, Very sheltered
Tidal streams Moderately strong (1-3 kn), Weak (>1 kn), Very weak (negligible)
Substratum Mixed muddy sand with gravel, pebbles and cobbles
Zone Infralittoral
Depth Band 0-5 m, 5-10 m, 10-20 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.SMp.KSwSS.LsacR <I>Laminaria saccharina</I> and red seaweeds on infralittoral sediments

  • 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.


On infralittoral mixed muddy substrata communities characterised by the kelp Laminaria saccharina and mixed filamentous and foliose red algae can be found. This biotope contains a number of sub-biotopes distinguished by the degree of either wave or tidal exposure. In moderately strong tidal streams in exposed areas Laminaria is sparse and dense stands of red seaweeds are found attached to the boulders and cobbles that make up a large proportion of the sediment (LsacR.CbPb). As the degree of wave and/or tidal exposure decreases there is a change in community structure, with the density of Laminaria and the diversity of red algal species increasing (LsacR.Gv). As the environment becomes more stable a number of brown algal species are able to inhabit this environment and a rich infauna develops (LsacR.Sa). In the most sheltered examples of this biotope a diverse muddy sediment infauna can be found and the 'Trailliella' phase of Bonnemaisonia hamifera may develop (LsacR.Mu).


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
Cerianthus lloydii 2 Occasional 41-60 %
Chaetopterus variopedatus 1 Occasional 21-40 %
Terebellidae 2 Occasional 21-40 %
Lanice conchilega 2 Occasional 21-40 %
Pomatoceros triqueter 2 Occasional 41-60 %
Pagurus bernhardus 6 Occasional 61-80 %
Liocarcinus depurator 3 Occasional 41-60 %
Gibbula magus 1 Occasional 21-40 %
Gibbula cineraria 2 Occasional 41-60 %
Asterias rubens 7 Occasional 61-80 %
Echinus esculentus 2 Occasional 41-60 %
Bonnemaisonia asparagoides 2 Occasional 21-40 %
Corallinaceae 2 Occasional 41-60 %
Rhodophyllis divaricata 1 Occasional 21-40 %
Halarachnion ligulatum 2 Occasional 21-40 %
Plocamium cartilagineum 4 Occasional 41-60 %
Lomentaria clavellosa 1 Occasional 21-40 %
Pterothamnion plumula 1 Occasional 21-40 %
Delesseria sanguinea 1 Occasional 21-40 %
Phycodrys rubens 2 Occasional 21-40 %
Brongniartella byssoides 2 Occasional 41-60 %
Polysiphonia elongata 2 Occasional 21-40 %
Dictyota dichotoma 2 Occasional 21-40 %
Desmarestia aculeata 2 Occasional 21-40 %
Desmarestia viridis 2 Occasional 21-40 %
Chorda filum 1 Occasional 21-40 %
Laminaria saccharina 7 Occasional 61-80 %
Ulva 2 Occasional 21-40 %

Similar biotopes or habitat types

Not applicable or unknown.

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