Skip to Content

Marine Habitat Classification


Description of biotope or habitat type

To understand more about what this page is describing, see How to use the classification. See also How to cite.

   Sparse sponges, Nemertesia spp. and Alcyonidium diaphanum on circalittoral mixed substrata


Habitat (physical) description

Salinity Full (30-35 ppt)
Wave exposure Moderately exposed
Tidal streams Moderately strong (1-3 kn)
Substratum Boulders; cobbles; pebbles
Zone Circalittoral
Depth Band 10-20 m, 20-30 m
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 CR.HCR.XFa.SpNemAdia Sparse sponges, <I>Nemertesia</I> spp. and <I>Alcyonidium diaphanum</I> on circalittoral mixed substrata

  • 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'
  • Predicted extent of the level 3 (for sublittoral rock & deep sea) or 4 (for sublittoral sediment) habitat

Point data based on records in the UK Marine Recorder Snapshot. Predicted habitat extent is from UKSeaMap.

Description

This biotope is found on moderately wave-exposed sand-scoured, circalittoral boulders, cobbles and pebbles that are subject to moderately strong tidal streams (referred to as lag-cobbles locally). It is characterised by sparse sponges and a diverse bryozoan and hydroid turf. The sparse sponge community is primarily composed of Dysidea fragilis and Scypha ciliata. The mixed faunal turf is composed of Nemertesia antennina, Nemertesia ramosa, Halecium halecinum, Sertularia argentea, Alcyonium digitatum, Bugula flabellata, Bugula turbinata, Bugula plumosa, Flustra foliacea, Cellepora pumicosa, Alcyonidium diaphanum, Cellaria fistulosa and crisiid bryozoans. The anemones Epizoanthus couchii, Sagartia elegans and Cerianthus lloydii may also be recorded. Echinoderms such as the starfish Asterias rubens, Crossaster papposus, Henricia oculata and the crinoid Antedon bifida. Other species present include the colonial ascidian Clavelina lepadiformis, the barnacle Balanus crenatus, the top shell Gibbula cineraria, the polychaete Pomatoceros triqueter, the ascidian Morchellium argus, Prosthecareus vittatus and the crab Cancer pagurus. It is distributed off Pen Llyn and over considerable areas of the Irish Sea.

Situation

No situation data available.

Temporal variation

Not known.

Characterising Species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Scypha ciliata 1 Occasional 21-40 %
Dysidea fragilis 2 Occasional 41-60 %
Halecium halecinum 1 Occasional 41-60 %
Sertularia argentea 1 Occasional 21-40 %
Nemertesia antennina 10 Occasional 81-100 %
Nemertesia ramosa 3 Occasional 61-80 %
Alcyonium digitatum 6 Occasional 81-100 %
Cerianthus lloydii 2 Occasional 41-60 %
Epizoanthus couchii 5 Occasional 61-80 %
Sagartia elegans 2 Frequent 41-60 %
Prostheceraeus vittatus 1 Rare 41-60 %
Pomatoceros triqueter 1 Occasional 41-60 %
Balanus crenatus 2 Common 41-60 %
Cancer pagurus 1 Occasional 21-40 %
Gibbula cineraria 1 Occasional 41-60 %
Crisiidae 1 Frequent 21-40 %
Alcyonidium diaphanum 2 Occasional 61-80 %
Flustra foliacea 3 Occasional 61-80 %
Bugula flabellata 4 Occasional 61-80 %
Bugula plumosa 1 Occasional 21-40 %
Bugula turbinata 2 Occasional 41-60 %
Cellaria fistulosa 1 Common 21-40 %
Cellepora pumicosa 1 Occasional 21-40 %
Antedon bifida 2 Occasional 41-60 %
Crossaster papposus 2 Occasional 41-60 %
Henricia oculata 1 Occasional 41-60 %
Asterias rubens 3 Occasional 61-80 %
Clavelina lepadiformis 5 Occasional 61-80 %
Morchellium argus 1 Frequent 21-40 %

Similar biotopes

CR.HCR.XFa.FluCoAs.X
This biotope occurs under more wave-exposed conditions subject to slightly weaker tidal streams. Flustra foliacea is present in higher abundances in FluCoAs.X.

Biotope history

Classification Habitat code
97.06 CR.MCR.ByH.SNemAdia

Back to top