Description of biotope or habitat type
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Ascophyllum nodosum with epiphytic sponges and ascidians on variable salinity infralittoral rock
Physical habitat description
| Salinity | Variable (18-35 ppt) |
|---|---|
| Wave exposure | Extremely sheltered |
| Tidal streams | Weak (>1 kn), Very weak (negligible) |
| Substratum | Bedrock; boulders and cobbles |
| Zone | Infralittoral |
| Depth Band | 0-5 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.
- 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
Dense subtidal stands of Ascophyllum nodosum, heavily epiphytised by sponges and ascidians in lagoon-like habitats. The wracks Fucus vesiculosus and Fucus serratus can be present along with the brown seaweed Chorda filum and the red seaweed Polyides rotunda. The crab Carcinus maenas can be present between the A. nodosum holdfasts along with the shrimps Mysidae.
Situation
Nearby rock often supports similar biotopes of submerged fucoids and green seaweeds (FChoG). Slightly deeper rock often supports Saccharina latissima (Lsac.Ft), usually surrounded by more extensive areas of sediment. Seagrass beds thrive well in the muddy sand of these lagoons and often cover large areas. They include both Ruppia maritima and Zostera subg. Zostera marina (Rup and Zmar).
Temporal variation
Unknown.
Characterising species
| Taxon | Relative importance of taxon for defining this community (%) | Typical abundance - SACFOR scale | % of core records where taxon was recorded |
|---|---|---|---|
| Ascophyllum nodosum | 40 | Frequent | 81-100% |
| Carcinus maenas | 21 | Occasional | 81-100% |
| Polyides rotunda | 7 | Frequent | 41-60% |
| Chorda filum | 4 | Frequent | 41-60% |
| Fucus serratus | 4 | Frequent | 41-60% |
| Fucus vesiculosus | 4 | Frequent | 61-80% |
| Mysidae | 3 | Occasional | 41-60% |
Similar biotopes or habitat types
Not applicable or unknown.
Classification history of this biotope or habitat type
| Classification version | Code |
|---|---|
| 1997 (97.06) | SLR.AscSAs |