Description of [Laminaria hyperborea] park with hydroids, bryozoans and sponges on tide-swept lower infralittoral rock
Exposed to moderately wave-exposed, strongly tide-swept, rock with Laminaria hyperborea park characterised by a rich under-storey and stipe flora of foliose seaweeds such as Phycodrys rubens, Plocamium cartilagineum, Hypoglossum hypoglossoides, Kallymenia reniformis, Cryptopleura ramosa and Delesseria sanguinea. The red seaweed Heterosiphonia plumosa can be present. The foliose brown seaweed Dictyota dichotoma and coralline crust are often present as well. Amongst the red seaweeds is a rich fauna comprising sponges (Pachymatisma johnstonia, Stelligera rigida, Esperiopsis fucorum and Dysidea fragilis), anthozoans (Alcyonium digitatum and Caryophyllia smithii), hydroids (Aglaophenia pluma and Nemertesia antennina), colonial ascidians (Clavelina lepadiformis and Morchellium argus) and bryozoans such as Electra pilosa. Both the flora and fauna of this biotope are similar to the wave exposed kelp park (unit A3.1152), but A3.1152 has a greater faunal component including the barnacle Balanus crenatus, the echinoderm Asterias rubens and the crab Necora puber. Situation: This biotope generally occurs below a tide-swept L. hyperborea kelp forest (unit A3.2121). As this biotope occurs over such a range of wave exposures a variety of circalittoral biotopes can occur beneath it: for example, Exposed, tide-swept rock (unit A4.11) or moderately exposed tide-swept rock (unit A4.21).