Sheltered mixed sediments, usually subject to variable salinity conditions. The infauna is very diverse, dominated by a range of polychaetes including Exogone naidina, Sphaerosyllis taylori, Pygospio elegans, Chaetozone gibber, Cirriformia tentaculata, Aphelochaeta marioni, Capitella capitata, Mediomastus fragilis, and Melinna palmata. The oligochaete worms Tubificoides benedii and T. pseudogaster are abundant, as is the cockle Cerastoderma edule. A large range of amphipods may occur, including Melita palmata, Microprotopus maculatus, Aora gracilis and Corophium volutator. The bivalves Abra alba and A. nitida may occur. The barnacle Elminius modestus may be abundant where the sediment has stones on the surface. Situation: Mid shore, lower shore, as extension of shallow sublittoral biotope.