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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.

   Seaweeds in sediment-floored eulittoral rockpools


Habitat (physical) description

Salinity Full (30-35 ppt)
Wave exposure Exposed, Moderately exposed, Sheltered
Tidal streams
Substratum Bedrock with cobbles, pebbles and/ or sand
Zone Eulittoral
Depth Band Lower shore, Mid shore
Other Features Sand abrasion/ covered rock in rockpool; or unstable sediment (gravel/pebbles)

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 LR.FLR.Rkp.SwSed Seaweeds in sediment-floored eulittoral rockpools

  • 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

Rockpools with sediment (mud, sand, gravel) floors support distinct communities of scour-tolerant seaweeds. Deep pools with sediment are similar to FK, and are typically dominated by fucoids and kelp (Fucus serratus, Laminaria digitata, Laminaria saccharina and Saccorhiza polyschides). Areas of hard substrata near to the interface with the sediment are, however, characterised by a range of sand-tolerant seaweeds such as Furcellaria lumbricalis, Polyides rotundus, Ahnfeltia plicata and Rhodochorton purpureum (compare with FK). Chorda filum may occur attached to pebbles and shells embedded within the sediment while the top shell Gibbula cineraria can be found underneath or among the pebbles. In pools with large areas of sand, infaunal species such as Arenicola marina and Lanice conchilega often occur. The seagrass Zostera spp. may occur in some pools where stable sand is present. Shallow rockpools with cobble and pebble floors, often with an underlying layer of sediment, support red algal tufts consisting of coralline crust, Corallina officinalis, Chondrus crispus, Mastocarpus stellatus mixed with Ceramium spp. and the green seaweeds Cladophora spp. and Enteromorpha intestinalis. The long list of characterising species is partly due to low similarity between the available records and care should be taken not to interpret this solely as a very high species richness.

Situation

Rockpools throughout the eulittoral zone in bedrock on exposed to sheltered shores.

Temporal variation

Seasonal fluctuations in the abundance of ephemeral seaweeds will occur.

Characterising Species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Arenicola marina 1 Rare 21-40 %
Gibbula cineraria 2 Occasional 41-60 %
Patella vulgata 2 Occasional 21-40 %
Littorina littorea 5 Frequent 41-60 %
Corallinaceae 11 Frequent 61-80 %
Corallina officinalis 13 Frequent 61-80 %
Furcellaria lumbricalis 1 Occasional 21-40 %
Chondrus crispus 6 Occasional 61-80 %
Polyides rotundus 1 Occasional 21-40 %
Ceramium 3 Frequent 41-60 %
Ceramium nodulosum 3 Frequent 21-40 %
Mastocarpus stellatus (petrocelis) 2 Frequent 21-40 %
Laminaria digitata 3 Frequent 41-60 %
Fucus serratus 5 Occasional 41-60 %
Enteromorpha intestinalis 3 Frequent 21-40 %
Ulva lactuca 5 Occasional 41-60 %
Cladophora 2 Occasional 41-60 %

Similar biotopes

Not applicable or unknown.

Biotope history

Classification Habitat code
96.7 Includes RKP.RBwn
6.95 LRK.FK.SP
96.7 RKP.FK.Snd

Photos

LR.FLR.RKP.SwSed Seaweeds in sediment-floored eulittoral rockpools, Broad Stones, Farnes. Tom Mercer © JNCC
LR.FLR.RKP.SwSed Seaweeds in sediment-floored eulittoral rockpools, Broad Stones, Farnes. Tom Mercer © JNCC
LR.FLR.RKP.SwSed Seaweeds in sediment-floored eulittoral rockpools, Broad Stones, farnes. Tom Mercer © JNCC
LR.FLR.RKP.SwSed Seaweeds in sediment-floored eulittoral rockpools, Broad Stones, farnes. Tom Mercer © JNCC
LR.FLR.RKP.SwSed Seaweeds in sediment-floored eulittoral rockpools, S of Rosemullion Head. Keith Hiscock © JNCC
LR.FLR.RKP.SwSed Seaweeds in sediment-floored eulittoral rockpools, S of Rosemullion Head. Keith Hiscock © JNCC

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