Caryophyllia smithii, Swiftia pallida and large solitary ascidians on exposed or moderately exposed circalittoral rock

English name: Caryophyllia smithii, Swiftia pallida and large solitary ascidians on exposed or moderately exposed circalittoral rock

Quick facts

EUNIS habitat type code A4.2112
Bern Convention Included in a Resolution 4 habitat type at a higher level (A4)

Description (English)

This variant typically occurs on exposed to moderately wave-exposed, circalittoral bedrock and boulders rock subject to mainly weak tidal streams and has a thin layer of silt present. It is found predominantly from 10-30m water depth. From afar, this biotope is mostly distinguished by the frequently occurring seafan Swiftia pallida, encrusting red algae and the abundant cup coral Caryophyllia smithii. This biotope has quite an impoverished appearance, compared with unit A4.133 which has a strong sponge component. Other species present are typically in low abundance. Echinoderms such as Echinus esculentus, Antedon bifida, Antedon petasus, Leptometra celtica, Marthasterias glacialis, Luidia ciliaris and Asterias rubens may be recorded. Large hydroids such as Nemertesia antennina and Nemertesia ramosa may occasionally be seen in isolated clumps on the tops of boulders and rocky outcrops. The anthozoan Parazoanthus anguicomus may be recorded. Bryozoans such as Parasmittina trispinosa and Porella compressa are occasionally observed. The polychaete Pomatoceros triqueter may be observed encrusting the sides of rocks and boulders while occasional Alcyonium digitatum may also be seen. A small suite of large ascidians may be present, including Ascidia mentula, Clavelina lepadiformis, Ciona intestinalis, Diazona violacea and Ascidia virginea. Sponges are typically absent from this biotope, although Cliona celata may be recorded occasionally. The top shell Gibbula cineraria is usually present. Under boulders and overhangs, the squat lobster Munida rugosa can usually be seen hiding. All these records are from the west coast of Scotland (East coast of Lewis /Outer Hebrides).
Situation: Above this biotope in the infralittoral zone, sheltered kelp forests are usually found, with species such as Laminaria hyperborea, Laminaria saccharina and Sacchoriza polyschides. This biotope is found on bedrock and boulders, which may either be protruding from the surrounding sediment, or the sediment may be in a separate zone below the bedrock. These sediments may either be deep mud (with species such as Pachycerianthus and Nephrops ) on the sheltered sites or slightly coarser sediments (with Pennatula and Virgularia) on slightly more exposed sites.

Source: EUNIS habitat classification

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Species mentioned in habitat description

Invertebrates Alcyonium digitatum
Invertebrates Antedon bifida
Invertebrates Antedon petasus
Invertebrates Ascidia mentula
Invertebrates Ascidia virginea
Invertebrates Asterias rubens
Invertebrates Caryophyllia smithii
Invertebrates Ciona intestinalis
Invertebrates Clavelina lepadiformis
Invertebrates Cliona celata
Invertebrates Diazona violacea
Invertebrates Echinus esculentus
Invertebrates Gibbula cineraria
Algae Laminaria hyperborea
Algae Laminaria saccharina
Invertebrates Leptometra celtica
Invertebrates Luidia ciliaris
Invertebrates Marthasterias glacialis
Invertebrates Munida rugosa
Invertebrates Nemertesia antennina
Invertebrates Nemertesia ramosa
Invertebrates Parasmittina trispinosa
Invertebrates Parazoanthus anguicomus
Invertebrates Pomatoceros triqueter
Invertebrates Porella compressa
Invertebrates Swiftia pallida
Species scientific name English common name Species group
Alcyonium digitatum Invertebrates
Antedon bifida Invertebrates
Antedon petasus Invertebrates
Ascidia mentula Invertebrates
Ascidia virginea Invertebrates
Asterias rubens Invertebrates
Caryophyllia smithii Invertebrates
Ciona intestinalis Invertebrates
Clavelina lepadiformis Invertebrates
Cliona celata Invertebrates
Diazona violacea Invertebrates
Echinus esculentus Invertebrates
Gibbula cineraria Invertebrates
Laminaria hyperborea Algae
Laminaria saccharina Algae
Leptometra celtica Invertebrates
Luidia ciliaris Invertebrates
Marthasterias glacialis Invertebrates
Munida rugosa Invertebrates
Nemertesia antennina Invertebrates
Nemertesia ramosa Invertebrates
Parasmittina trispinosa Invertebrates
Parazoanthus anguicomus Invertebrates
Pomatoceros triqueter Invertebrates
Porella compressa Invertebrates
Swiftia pallida Invertebrates

Other classifications

Classification Code Habitat type name Relationship type
Marine Habitat Classification Britain/Ireland 0405 CR.MCR.EcCr.CarSwi.LgAs <I>Caryophyllia smithii</I>, <I>Swiftia pallida</I> and large solitary ascidians on exposed or moderately exposed circalittoral rock source
CORINE Land Cover 5.2.3. Sea and ocean n/a
For relation to plant communities (syntaxa), see Vegetation types

History

Classification Code Habitat type name Relationship type
EUNIS Habitat Classification 200410 A4.2112 Caryophyllia smithii, Swiftia pallida and large solitary ascidians on exposed or moderately exposed circalittoral rock same
EUNIS Habitat Classification 200308 A3.614 Erect sponges and Swiftia pallida on slightly tide-swept moderately exposed circalittoral rock wider
EUNIS Habitat Classification 200202 A3.614 Erect sponges and Swiftia pallida on slightly tide-swept moderately exposed circalittoral rock overlap
EUNIS Habitat Classification 199910 A3.614 Erect sponges and Swiftia pallida on slightly tide-swept moderately exposed circalittoral rock overlap
MNCR BioMar 97.06 (Britain & Ireland) MCR.XFa.ErSSwi Erect sponges and Swiftia pallida on slightly tide-swept moderately exposed circalittoral rock overlap
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