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Marine Habitat Classification


Description of biotope or habitat type

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   Maerl beds


Habitat (physical) description

Salinity Full (30-35 ppt)
Wave exposure Moderately exposed, Sheltered, Very sheltered, Extremely sheltered
Tidal streams Moderately strong (1-3 kn), Weak (>1 kn), Very weak (negligible)
Substratum Gravels, clean sands
Zone Infralittoral
Depth Band 0-5 m, 5-10 m, 10-20 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 SS.SMp.Mrl Maerl beds

  • 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

Beds of maerl in coarse clean sediments of gravels and clean sands, which occur either on the open coast or in tide-swept channels of marine inlets (the latter often stony). In fully marine conditions the dominant maerl is typically Phymatolithon calcareum (SMP.Pcal), whilst under variable salinity conditions in some sealochs beds of Lithothamnion glaciale (SMP.Lgla) may develop.

Situation

No situation data available.

Temporal variation

No temporal data available.

Characterising Species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Cerianthus lloydii 3 Frequent 41-60 %
Nemertea 2 41-60 %
Nematoda 9 Common 81-100 %
Harmothoe impar 1 Common 61-80 %
Kefersteinia cirrata 4 81-100 %
Eurysyllis tuberculata 1 Common 41-60 %
Trypanosyllis coeliaca 1 Frequent 41-60 %
Sphaerosyllis taylori 2 Frequent 41-60 %
Aonides paucibranchiata 1 61-80 %
Chaetopterus variopedatus 2 Occasional 21-40 %
Mediomastus fragilis 4 Frequent 81-100 %
Lanice conchilega 2 Occasional 21-40 %
Polycirrus 3 Common 61-80 %
Chone duneri 5 Common 61-80 %
Pomatoceros triqueter 2 Occasional 21-40 %
Grania 6 Abundant 41-60 %
Parametaphoxus fultoni 7 Common 61-80 %
Socarnes erythrophthalmus 4 Abundant 41-60 %
Austrosyrrhoe fimbriatus 1 Common 21-40 %
Ceradocus semiserratus 3 Common 41-60 %
Gammaropsis cornuta 2 Frequent 41-60 %
Leptocheirus hirsutimanus 2 Frequent 41-60 %
Leptocheirus pectinatus 3 Abundant 41-60 %
Cymodoce truncata 2 41-60 %
Vauntompsonia cristata 2 61-80 %
Cumella pygmaea 3 Common 41-60 %
Nannastacus unguiculatus 2 Common 41-60 %
Pagurus bernhardus 6 Occasional 61-80 %
Liocarcinus depurator 2 Occasional 41-60 %
Gibbula magus 1 Occasional 21-40 %
Gibbula cineraria 2 Occasional 21-40 %
Dikoleps pusilla 2 Abundant 41-60 %
Onoba aculeus 3 Super abundant 41-60 %
Asterias rubens 10 Occasional 61-80 %
Amphipholis squamata 4 Super abundant 61-80 %
Echinus esculentus 2 Occasional 21-40 %
Neopentadactyla mixta 1 Occasional 21-40 %
Lithothamnion glaciale 1 Frequent 21-40 %
Phymatolithon calcareum 15 Common 61-80 %
Plocamium cartilagineum 3 Occasional 41-60 %
Phycodrys rubens 1 Occasional 21-40 %
Brongniartella byssoides 1 Occasional 21-40 %
Trailliella intricata 1 Frequent 21-40 %
Dictyota dichotoma 4 Occasional 41-60 %
Desmarestia viridis 1 Occasional 21-40 %
Chorda filum 1 Frequent 21-40 %
Laminaria saccharina 5 Occasional 41-60 %

Similar biotopes

Not applicable or unknown.

Biotope history

Classification Habitat code
97.06 IGS.Mrl
97.06 IMX.MrlMx

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