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IR.FIR.SG.FoSwCC
Foliose seaweeds and coralline crusts in surge gully entrances

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Habitat (physical) description

Distribution

 Salinity: Full (30-35 ppt) 
 Wave exposure: Extremely exposed, Very exposed, Exposed 
 Tidal streams: Moderately strong (1-3 kn), Weak (>1 kn), Very weak (negligible) 
 Substratum: Bedrock; boulders 
 Zone: Infralittoral 
 Depth Band: 0-5 m, 5-10 m, 10-20 m 
 Other Features: Boulder-scoured and wave-surged 

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.FIR.SG.FoSwCC  Foliose seaweeds and coralline crusts in surge gully entrances
Distribution of habitat IR.FIR.SG.FoSwCC Foliose seaweeds and coralline crusts in surge gully entrances, based on records on the UK Marine Recorder database and EUSeaMap. Red dots represent records on which the biotope is based. Blue dots show other certain records, black dots show records tentatively assigned to this biotope. Yellow areas show level 2 and 3 sublittoral and deep-sea habitats prediced by EUSeaMap within UK waters.

Biotope description

This biotope is found on steep wave-surged entrances to gullies and caves and on unstable boulders in the entrance to caves and gullies. The rock may be abraded by the movement of the boulders and cobbles in heavy surge and tends to be dominated by dense foliose seaweeds that grow rapidly in the calmer summer months. Beneath the foliose seaweeds the rock surface is typically covered with coralline crusts, which are longer-lived, and tolerant of abrasion. The flora of this biotope is relatively varied, depending upon the amount of light and degree of abrasion or rock mobility with red seaweeds such as Cryptopleura ramosa, Plocamium cartilagineum, Odonthalia dentata, Callophyllis laciniata, Phycodrys rubens, Hypoglossum hypoglossoides, Phyllophora crispa and Corallina officinalis. The brown seaweed Dictyota dichotoma also occurs in these conditions, since it is tolerant of some sand scour. During the summer months small fast-growing kelp plants can arise in this biotope, although the mobility of the substratum prevents the kelp from forming a kelp forest. Dense swathes of very young kelp such as Laminaria hyperborea are, however, not uncommon. The faunal community consist of the anemone Urticina felina, the sponge Halichondria panicea and the ascidian Dendrodoa grossularia. More mobile fauna include the echinoderms Asterias rubens and Echinus esculentus, the top shell Gibbula cineraria and the crab Cancer pagurus.

Situation

Further into the cave or gully, beyond the dense red seaweeds of FoSwCC, the vertical rock grades to either an ascidian and sponge dominated community or sponge crusts and anthozoans (CrSpAsAn/CrSpAsDenB). Further into the cave or gully the floor and any boulders or cobbles are generally scoured clean or may support coralline encrusting algae (CC.Mo). Above the red seaweeds, steep rock surfaces often support a kelp community (LhypR or Lhyp) or in shallower water Alaria esculenta is usually present (Ala.Myt).

Temporal variation

Unknown.

Similar biotopes

IR.HIR.KSed.LsacSacThis biotope occurs in a similar depth and conditions as FoSwCC, though LsacSac often occurs further away from the cave / gully entrance on larger boulders. As such, the greater (relative) stability of the boulders allows the opportunistic kelps to survive long enough to form a forest.

Characterising Species

Taxa Frequency Typical Abundance % Contribution to similarity
Halichondria panicea O 2
Urticina felina O 5
Cancer pagurus O 1
Gibbula cineraria F 3
Asterias rubens O 3
Echinus esculentus O 1
Dendrodoa grossularia F 3
Corallinaceae A 21
Corallina officinalis O 1
Callophyllis laciniata O 3
Phyllophora crispa O 1
Plocamium cartilagineum F 8
Cryptopleura ramosa F 10
Hypoglossum hypoglossoides O 3
Phycodrys rubens O 3
Odonthalia dentata O 5
Dictyota dichotoma O 4
Laminaria hyperborea O 1

Example photographs of biotope


Cover of ascidians and seaweeds mainly Botrylloides leachi and Cryptopleura ramosa, SW side, Rockall., Christine Howson, © JNCC
Click on an image for a larger view


Version 15.03 of the classification adds a deep-sea section to version 04.05; therefore superseding version 04.05, 97.06 and 03.02.

This online classification should be cited as:

JNCC (2015) The Marine Habitat Classification for Britain and Ireland Version 15.03 [Online]. [Date accessed]. Available from: jncc.defra.gov.uk/MarineHabitatClassification

Information from the shallower section (up to sublittoral sediment, taken from Version 04.05) be cited as the report accompanying Version 04.05, as follows:

CONNOR, D.W., J.H. ALLEN, N.GOLDING, K.L.HOWELL, L.M. LIEBERKNECHT, K.O. NORTHEN AND J.B. REKER (2004) The Marine Habitat Classification for Britain and Ireland Version 04.05. In: JNCC (2015) The Marine Habitat Classification for Britain and Ireland Version 15.03 [Online]. [Date accessed].
Available from: jncc.defra.gov.uk/MarineHabitatClassification
ISBN 1 861 07561 8


Information from the deep-sea section (added in March 2015) should be cited as the report accompanying the deep-sea section, as follows:

PARRY, M.E.V., K.L. HOWELL, B.E. NARAYANASWAMY, B.J. BETT, D.O.B. JONES, D.J. HUGHES, N. PIECHAUD, T.D. NICKELL, H. ELLWOOD, N. ASKEW, C. JENKINS and E. MANCA (2015) A Deep-sea Section for the Marine Habitat Classification of Britain and Ireland. JNCC report 530. In: JNCC (2015) The Marine Habitat Classification for Britain and Ireland Version 15.03 [Online]. [Date accessed].
Available from: jncc.defra.gov.uk/MarineHabitatClassification
ISSN 0963 8901