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Marine Habitat Classification


Description of biotope or habitat type

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   Laminaria hyperborea park and foliose red seaweeds on moderately exposed lower infralittoral rock


Habitat (physical) description

Salinity Full (30-35 ppt)
Wave exposure Moderately exposed
Tidal streams Moderately strong (1-3 kn), Weak (>1 kn), Very weak (negligible)
Substratum Bedrock; boulders
Zone Infralittoral - lower
Depth Band 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 IR.MIR.KR.Lhyp.Pk <I>Laminaria hyperborea</I> park and foliose red seaweeds on moderately exposed lower infralittoral rock

  • 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

Below the dense kelp forest (Lhyp.Ft) on moderately exposed lower infralittoral bedrock and boulders, the kelp thins out to form a park. Beneath the kelp, the rock and kelp stipes are covered by an often dense turf of foliose red seaweeds such as Callophyllis laciniata, Plocamium cartilagineum, Delesseria sanguinea, Hypoglossum hypoglossoides, Cryptopleura ramosa, Callophyllis laciniata and Phycodrys rubens. Coralline crusts are often present on the rock surface. Many species of red seaweed found in this biotope occur at greater abundance in the shallower kelp forest. Other seaweeds, such as the red seaweeds Bonnemaisonia asparagoides and Hypoglossum hypoglossoides as well as the brown seaweed Dictyota dichotoma are more abundant in this zone than the upper infralittoral. The faunal component of this biotope is similar to that found below the kelp in the upper infralittoral zone and include the hydroid Obelia geniculata, the ascidian Clavelina lepadiformis, the anthozoans Urticina felina, Alcyonium digitatum and Caryophyllia smithii, the tube-building polychaete Pomatoceros triqueter and the gastropods Calliostoma zizyphinum and Gibbula cineraria. The gastropods Gibbula cineraria and Calliostoma zizyphinum and the echinoderm Echinus esculentus can be found grazing on the rock. Other echinoderms present include Asterias rubens and Antedon bifida which can be locally abundant, particularly in the north-west.

Situation

This biotope generally occurs below L. hyperborea forest (Lhyp.Ft) and marks the lower limit of the infralittoral rock. Occasionally a narrow band of foliose seaweeds (FoR) may occur below the kelp park but generally circalittoral biotopes are found.

Temporal variation

The under-storey of foliose and filamentous seaweeds will diminish towards the autumn and regrow in the spring. When grazing urchins (predominantly E. esculentus) reach a large number in the kelp park their voracious grazing can substantially alter the community structure of the biotope, removing most of the seaweeds and leaving only coralline crusts on the rock. This is common around the coast of Scotland, particularly in Shetland and such sites should be recorded as Lhyp.GzFt.

Characterising Species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Obelia geniculata 2 Frequent 21-40 %
Alcyonium digitatum 2 Occasional 41-60 %
Urticina felina 1 Occasional 41-60 %
Caryophyllia smithii 2 Occasional 41-60 %
Pomatoceros triqueter 4 Frequent 61-80 %
Gibbula cineraria 2 Occasional 41-60 %
Antedon bifida 2 Frequent 41-60 %
Asterias rubens 5 Occasional 61-80 %
Echinus esculentus 5 Occasional 61-80 %
Clavelina lepadiformis 2 Occasional 41-60 %
Bonnemaisonia asparagoides 2 Occasional 41-60 %
Corallinaceae 7 Frequent 61-80 %
Callophyllis laciniata 2 Occasional 41-60 %
Plocamium cartilagineum 5 Frequent 61-80 %
Cryptopleura ramosa 1 Occasional 21-40 %
Delesseria sanguinea 8 Frequent 81-100 %
Hypoglossum hypoglossoides 1 Occasional 41-60 %
Phycodrys rubens 4 Frequent 61-80 %
Dictyota dichotoma 5 Frequent 61-80 %
Laminaria hyperborea 12 Frequent 81-100 %

Similar biotopes

IR.HIR.KFaR.LhypR.Pk
Found in areas of greater wave exposure and has a greater faunal component (cushion sponges, anthozoans: Sagartia elegans, Corynactis viridis and Actinothoe sphyrodeta, more bryozoans such as Crisia spp. and epilithic bryozoan crusts).

IR.MIR.KR.LhypT.Pk
Found above the kelp park and has a greater abundance of kelps but similar species composition.

IR.MIR.KR.LhypT.Pk
Occurs in sites subject to accelerated tidal currents, generally with a more prominent filter feeder community. A larger variety of sponges such as Halichondria panicea and Esperiopsis fucorum, the bryozoans Alcyonidium diaphanum and Flustra foliacea and the barnacle Balanus balanus are found in greater abundance in the tide-swept kelp park.

IR.MIR.KR.Lhyp.GzPk
Lacks the dense understorey of red seaweeds beneath the kelp canopy with the brown seaweeds D. dichotoma and Desmarestia spp. more prominent on the rock. The kelp stipes may still be covered with dense seaweeds but can also be bare from grazing.

Photos

IR.MIR.KR.Lhyp.Pk Laminaria hyperborea park and foliose red seaweeds on moderately exposed lower infralittoral rock, SE Eddystone Rock, Plymouth. Paul Brazier © JNCC
IR.MIR.KR.Lhyp.Pk Laminaria hyperborea park and foliose red seaweeds on moderately exposed lower infralittoral rock, SE Eddystone Rock, Plymouth. Paul Brazier © JNCC

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