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Concept: [Laminaria saccharina], [Chorda filum] and dense red seaweeds on shallow unstable infralittoral boulders and cobbles in the eunishabitats vocabulary

Concept URI http://eunis.eea.europa.eu/eunishabitats/A3.123
Preferred label [Laminaria saccharina], [Chorda filum] and dense red seaweeds on shallow unstable infralittoral boulders and cobbles
Definition Seasonally disturbed unstable boulders and cobbles in very shallow water dominated by the fast-growing brown seaweed [Chorda filum] together with the kelp [Laminaria saccharina]. The brown seaweed [Desmarestia aculeata] is also typical of this disturbed environment as well encrusting coralline algae and brown crusts. Beneath the prolific growth of [C. filum], red and brown seaweeds densely cover many of the boulders, cobbles and pebbles. Other sediment-tolerant seaweeds such as species from the Ectocarpales (brown filamentous seaweeds) and the red seaweeds [Chondrus crispus], [Phyllophora pseudoceranoides], [Dilsea carnosa] and [Corallina officinalis] is normally present. Other red seaweeds which can be found here include [Chondria dasyphylla], [Brongniartella byssoides], [Polysiphonia elongata], [Ceramium nodolosum], [Cystoclonium purpureum, Heterosiphonia plumosa], [Rhodomela confervoides] and [Plocamium cartilagineum]. The brown seaweeds [Punctaria] sp. and [Cladostephus spongiosus] are generally present. The faunal component of this biotope is typically sparse - the starfish [Asterias rubens] and the crabs [Pagurus] [bernhardus] and [Necora puber] are amongst the most conspicuous animals. The bryozoan crust [Electra pilosa] colonise many of the algae along with the ascidian [Botryllus schlosseri]. Occasional the polychaete [Lanice conchilega] may occur in the sand between pebbles, and the anthozoan [Urticina felina] may be found amongst pockets of gravel along with the gastropod [Gibbula cineraria]. At some sites the rock beneath the algae can be occupied by the tube-building polychaete [Pomatoceros triqueter]. This biotope is also present at other open coast sites around the UK where suitable shallow, seasonally stable boulders, cobbles and pebbles occur. Typical examples of this biotope occur on the shallowest areas of the Sarns in Cardigan Bay, Wales, where reef crests are formed by embedded and mobile boulders, together with cobbles and pebbles in between (typically at 2-3m depth). Situation: This biotope occurs in shallow water, often on the crest of an infralittoral boulder/cobble bank and as such will not have any biotope 'above' it. More mobile areas of smaller boulders, cobbles and pebbles nearby may support dense ephemeral red seaweeds (EphR) or robust scour-tolerant red seaweeds on sand-covered rock (ProtAhn). The [Halidrys siliquosa] biotope XKHal also thrives under similar conditions, extending deeper than the shallow LsacChoR biotope. Deeper still in the circalittoral zone encrusting fauna is found on highly mobile mixed substrata (PomB). At a few sites, this biotope can occur within more extensive maerl beds (SS.SMP.Mrl) but more commonly is surrounded by sandy sediments (SS.SSa). Temporal variation: This biotope will change markedly with the seasons. During the winter months boulders and cobbles will be storm battered and overturned and much of the biota dislodged from the rocks. During more stable conditions in the late spring and summer months the fast-growing seaweeds that characterise this biotope ([C. filum] and [L. saccharina] in particular) will be quick to re-establish, growing at a phenomenal rate. The seasonal disturbance of the substratum prevents a stable [Laminaria hyperborea] forest from developing.
Notation A3.123
Status Valid
Status Modified 2014-01-31
Accepted Date 2014-01-31
Not Accepted Date
Has broader
Has exact match