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Marine Habitat Classification


Description of biotope or habitat type

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   Polychaetes and Angulus tenuis in littoral fine sand


Habitat (physical) description

Salinity Full (30-35 ppt), Variable (18-35 ppt)
Wave exposure Moderately exposed, Sheltered, Very sheltered, Extremely sheltered
Tidal streams
Substratum Fine sand
Zone
Depth Band Lower shore, Mid shore
Other Features

Download comparative physical and biological data. The comparative tables enable a rapid comparison of the species composition and principal physical characteristics between a given set of biotopes.

Distribution of habitat LS.LSa.FiSa.Po.Aten Polychaetes and <I>Angulus tenuis</I> in littoral fine sand

  • Records used to define the biotope (core records)
  • Other records assigned to this biotope, marked as 'certain'
  • Other records assigned to this biotope, marked as 'uncertain'

Point data based on records in the UK Marine Recorder Snapshot.

Description

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, AmSco.Eur, Po.Pful or Ol.FS may be present higher up on the shore than Po.Aten. Where it occurs under more sheltered conditions, Po.Aten may occur below or alongside muddy sand biotopes such as CerPo and BatCare.

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.

Characterising Species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale Typical abundance - (count per m2) % of core records where taxon was recorded
Nephtys cirrosa 5 Common 44 41-60 %
Paraonis fulgens 1 Abundant 40 1-20 %
Spio filicornis 3 Common 84 41-60 %
Bathyporeia elegans 2 Common 54 21-40 %
Bathyporeia pilosa 1 Common 96 21-40 %
Angulus tenuis 74 Abundant 434 81-100 %

Similar biotopes

LS.LSa.FiSa.Po.Pful
Occurs higher on the shore. The sediments of Po.Aten are more stable than in the case of Po.Pful and therefore support bivalves, especially A. tenuis.

LS.LSa.FiSa.Po.Ncir
Occurs lower on the shore in slightly coarser sand. A. tenuis is absent or occurs in very low abundance, Nephtys spp. dominate the infauna.

Biotope history

Classification Habitat code
97.06 LGS.S.AP.P (part)
97.06 LGS.S.AP.Pon (part)
6.95 LSND.AP (part)

Photos

LS.LSA.FISA.Po.Ang Polychaetes and Angulus tenuis in littoral fine sand, N of Llanaber (shore), Barmouth. Paul Brazier © JNCC
LS.LSA.FISA.Po.Ang Polychaetes and Angulus tenuis in littoral fine sand, N of Llanaber (shore), Barmouth. Paul Brazier © JNCC

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