Polychaetes and Angulus tenuis in littoral fine sand

Description (English)

This biotope occurs on the mid and lower shore on moderately wave-exposed and sheltered coasts, with predominantly fine sand which remains damp throughout the tidal cycle. The sediment is often rippled, and an anoxic layer may occasionally occur below a depth of 10 cm, though it is often patchy. The infaunal community is dominated by the abundant bivalve Angulus tenuis together with a range of polychaetes. The presence of polychaetes may be seen as coloured burrows running down from the surface of the sediment. Polychaetes that are characterising for this biotope include Nephtys cirrosa, Paraonis fulgens and Spio filicornis. Burrowing amphipods Bathyporeia spp. may occur in some samples of this biotope.
Situation: Where it occurs under moderately exposed conditions, units A2.2232, A2.2311 or A2.2221 may be present higher up on the shore than this unit. Where it occurs under more sheltered conditions, it may occur below or alongside muddy sand biotopes such as units A2.242 and A2.244.
Temporal variation: The infauna of this biotope may be reduced during winter, as increased storminess and wave action increases sediment mobility and may lead to some species migrating or being washed out of the sediment.

Source: EUNIS habitat classification