Description of [Polyides rotundus] and/or [Furcellaria lumbricalis] on reduced salinity infralittoral rock
Bedrock and boulders characterised by a dense turf of the red seaweeds Polyides rotundus and/or Furcellaria lumbricalis, often with a dense mat of filamentous brown and green seaweeds including Ectocarpaceae and Cladophora spp. Other red seaweeds presents include Chondrus crispus, Gracilaria gracilis and coralline crusts as well as the odd brown seaweed Chorda filum or Laminaria spp. Associated with these seaweeds are a variety of ascidians including Clavelina lepadiformis, Ascidiella aspersa, Ascidiella scabra and Ciona intestinalis as well as the anemones Anemonia viridis and Actinia equina and the sponge Halichondria panicea. More mobile fauna include the starfish Asterias rubens, the crab Carcinus maenas, the hermit crab Pagurus bernhardus, the opossum shrimps Mysidae and the gastropod Littorina littorea. Attached to the rock or cobbles are spirorbid polychaetes and the mussel Mytilus edulis. Please notice that part of this diversity is due to large differences between sites. Situation: Nearby rock (units A3.342 and A3.341) and seagrass Ruppia maritima dominating much of the surrounding muddy sediment (unit A5.5343). Mixed sediment supports filamentous green seaweeds e.g. Cladophora spp. and Derbesia marina on A5.528.