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Marine Habitat Classification


Description of biotope or habitat type

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   Caryophyllia smithii with faunal and algal crusts on moderately wave-exposed circalittoral rock


Habitat (physical) description

Salinity Full (30-35 ppt)
Wave exposure Exposed, Moderately exposed, Sheltered
Tidal streams Weak (>1 kn), Very weak (negligible)
Substratum Bedrock, boulders
Zone Circalittoral
Depth Band 10-20 m, 20-30 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 CR.MCR.EcCr.FaAlCr.Car <I>Caryophyllia smithii</I> with faunal and algal crusts on moderately wave-exposed circalittoral 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

This variant is typically found on the upper and vertical faces of exposed and moderately wave-exposed circalittoral rock, subject to very little water movement. Where this variant is found on slightly more wave-exposed sites, it tends to be found towards the bottom of its depth range. The rocky substratum has a grazed appearance, with encrusting red algae. Diversity of species is very low, possibly due to grazing pressure from the sea urchin Echinus esculentus. From afar, there is little evident epifauna attached to the rocks apart from the white, calcareous tubes of the polychaete Pomatoceros triqueter and the cup-coral Caryophyllia smithii. In addition, bryozoan crusts such as Parasmittina trispinosa are frequently seen. Under closer inspection, a few more species become apparent but few are typically characterising of this particular variant. The echinoderms Antedon bifida, Asterias rubens, Ophiothrix fragilis, Marthasterias glacialis, Ophiocomina nigra and Crossaster papposus are occasionally present. Sparse clumps of hydroids such as Halecium halecinum, Kirchenpaueria pinnata and Nemertesia antennina may be found attached to rocky outcrops or boulders. Small specimens of Alcyonium digitatum may be present. The ascidians Ciona intestinalis, Clavelina lepadiformis and Ascidia mentula also occur in this variant but are found in greater numbers in other biotopes. The top shells Calliostoma zizyphinum, Gibbula cineraria, and the saddle oyster Pododesmus patelliformis may be seen on the rock surface whilst the crab Cancer pagurus may be seen under boulders and in crevices. The anemone Metridium senile may be found under rocky overhangs and on the sides of boulders.

Situation

As FaAlCr.Car occurs on moderately wave-exposed coasts, kelp forests in the infralittoral zone shallower than this variant tend to be dominated by robust kelp species such as Laminaria hyperborea (Lhyp) and Saccorhiza polyschides. Immediately below FaAlC.Car (typically bedrock/boulder substratum), sublittoral sediment biotopes such as muddy sands, containing Nephrops norvegicus, Virgularia mirabilis and Funiculina quadrangularis are found. Occasionally, biotopes composed of coarser sand/gravelly material may be present, with species such as Peachea cylindrica and Neopentadactyla mixta. When wave exposure and tidal stream increase, FaAlC.Car tends to grade into FaAlC.Pom.

Temporal variation

Not known.

Characterising Species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Halecium halecinum 2 Occasional 41-60 %
Kirchenpaueria pinnata 1 Occasional 41-60 %
Nemertesia antennina 2 Occasional 41-60 %
Alcyonium digitatum 2 Occasional 61-80 %
Metridium senile 1 Occasional 41-60 %
Caryophyllia smithii 9 Frequent 81-100 %
Pomatoceros triqueter 8 Frequent 81-100 %
Cancer pagurus 1 Occasional 41-60 %
Gibbula cineraria 1 Occasional 41-60 %
Calliostoma zizyphinum 1 Occasional 41-60 %
Pododesmus patelliformis 2 Occasional 41-60 %
Parasmittina trispinosa 4 Frequent 61-80 %
Antedon bifida 4 Frequent 61-80 %
Crossaster papposus 1 Occasional 41-60 %
Asterias rubens 4 Occasional 61-80 %
Marthasterias glacialis 1 Occasional 41-60 %
Ophiothrix fragilis 2 Occasional 41-60 %
Ophiocomina nigra 1 Frequent 21-40 %
Echinus esculentus 9 Frequent 81-100 %
Clavelina lepadiformis 2 Occasional 41-60 %
Ciona intestinalis 2 Occasional 41-60 %
Ascidia mentula 2 Occasional 41-60 %
Corallinaceae 16 Abundant 81-100 %

Similar biotopes

CR.MCR.EcCr.FaAlCr.Pom
This variant tends to be found in slightly more wave-exposed areas subject to slightly stronger tides and is distinguished from FaAlCr.Car by its lack of C. smithii.

CR.LCR.BrAs.AmenCio.Ant
This variant is found in wave-sheltered sea lochs subject to only weak (if any) tidal streams. It has a barren appearance apart from frequent large solitary ascidians and a pink appearance due to encrusting corallines.

Photos

CR.MCR.ECCR.FaAlCr.Car Caryophyllia smithii with faunal and algal crusts on moderately wave-exposed circalittoral rock, S end of Kenmore, Loch Seaforth, Lewis. Sue Hiscock © JNCC
CR.MCR.ECCR.FaAlCr.Car Caryophyllia smithii with faunal and algal crusts on moderately wave-exposed circalittoral rock, S end of Kenmore, Loch Seaforth, Lewis. Sue Hiscock © JNCC
CR.MCR.ECCR.FaAlCr.Car Caryophyllia smithii with faunal and algal crusts on moderately wave-exposed circalittoral rock, N. Eilean Dubha, Loch Dughaill. David Connor © JNCC
CR.MCR.ECCR.FaAlCr.Car Caryophyllia smithii with faunal and algal crusts on moderately wave-exposed circalittoral rock, N. Eilean Dubha, Loch Dughaill. David Connor © JNCC

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