Description of biotope or habitat type
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Oligochaetes in variable or reduced salinity infralittoral muddy sediment
Physical habitat description
| Salinity | Reduced (18-30ppt), Variable (18-35 ppt) |
|---|---|
| Wave exposure | Very sheltered, Extremely sheltered |
| Tidal streams | Moderately strong (1-3 kn), Weak (>1 kn) |
| Substratum | Cohesive muddy sediment, sandy mud |
| Zone | Infralittoral |
| Depth Band | 0-5 m |
| Other Features | Possibly affected by a high biochemical oxygen demand |
Biotope origin
| Derived using data from | Various |
| Faunal group | Infauna |
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
Reduced or variable salinity muddy and sandy mud sediments characterised by oligochaetes, particularly of the genus Tubificoides or from the Enchytraeidae family. The abundance of the oligochaetes may vary by several orders of magnitude but very few other species will be present. Organic loading and poor water-exchange within the sediment lead to anoxic conditions which may explain the low species richness within this biotope.
Situation
This biotope is found towards the edges of tidal channels in estuaries where current velocities allow deposition of silt and the establishment of an infaunal community. The biotope may occur downstream of SS.SMu.SMuVS.LhofTtub, differentiated by the absence of the freshwater species, and adjacent to more mobile and sandier biotopes in the tidal channels.
Temporal variation
No temporal data available.
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 |
|---|---|---|---|---|
| Oligochaeta | 84 | Frequent | 245 | 61-80% |
| Diptera larva | 11 | Abundant | 61 | 21-40% |
| Tubificoides pseudogaster | 2 | 40 | 1-20% |
Similar biotopes or habitat types
SS.SMu.SMuVS.LhofTtub
SS.SMu.SMuVS.LhofTtub is similar to SS.SMu.SMuVS.OlVS however the latter lacks the freshwater element.
SS.SMu.SMuVS.CapTubi
SS.SMu.SMuVS.CapTubi can be separated from SS.SMu.SMuVS.OlVS by the presence of the polychaete Capitella capitata.
SS.SMu.SMuVS.MoMu
More mobile muds, which occur in areas with an extremely high suspended particulate component to the water column, SS.SMu.SMuVS.MoMu, may contain a very similar suite of species to SS.SMu.SMuVS.OlVS and can only positively be separated by a description of the sediment characteristics in the field.Classification history of this biotope or habitat type
| Classification version | Code | Habitat name |
|---|---|---|
| 2015 (15.03) | SS.SMu.SMuVS.OlVS | Oligochaetes in variable or reduced salinity infralittoral muddy sediment |
| 2004 (04.05) | SS.SMu.SMuVS.OlVS | Oligochaetes in variable or reduced salinity infralittoral muddy sediment |
| 1997 (97.06) | SS.IMU.EstMu.Tub | Tubificoides spp. in reduced salinity infralittoral muddy sediment |