Description of biotope or habitat type
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Limnodrilus hoffmeisteri, Tubifex tubifex and Gammarus spp. in low salinity infralittoral muddy sediment
Physical habitat description
| Salinity | Low (<18ppt) |
|---|---|
| Wave exposure | Very sheltered, Extremely sheltered |
| Tidal streams | Weak (>1 kn), Very weak (negligible) |
| Substratum | Cohesive muddy sediment |
| Zone | Infralittoral |
| Depth Band | 0-5 m |
| Other Features | Very low, fluctuating salinity; possibly with a high biochemical oxygen demand |
Biotope origin
| Derived using data from | Van Veen Grab |
| 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
Upper estuary muddy sediments with very low fluctuating salinity, characterised by the oligochaetes Limnodrilus hoffmeisteri and Tubifex tubifex. Other taxa may include Marenzelleria wireni, Gammarus zaddachi, Paranais litoralis and Baltidrilus costatus. The biotope contains elements of both freshwater and brackish communities.
Situation
This biotope is found in the transitional zone between the freshwater and brackish environments where tidal currents are sufficiently reduced to allow the deposition of fine silt and the establishment of an infaunal community. It may be found adjacent to SS.SSa.SSaVS.NintGam away from the stronger tidal streams.
Temporal variation
The position of this biotope in the estuary may vary seasonally depending on freshwater input (Gameson, 1982).
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 |
|---|---|---|---|---|
| Limnodrilus hoffmeisteri | 78 | Common | 1011 | 61-80% |
| Tubifex tubifex | 19 | 91 | 41-60% | |
| Marenzelleria wireni | 3 | 21 | 21-40% |
Similar biotopes or habitat types
SS.SMu.SMuVS.OlVS
SS.SMu.SMuVS.LhofTtub is similar to SS.SMu.SMuVS.OlVS however the latter lacks the freshwater element.
SS.SSa.SSaVS.NintGam
SS.SSa.SSaVS.NintGam may be found in conjunction with SS.SMu.SMuVS.LhofTtub, although it lacks appreciable numbers of oligochaetes.Classification history of this biotope or habitat type
| Classification version | Code | Habitat name |
|---|---|---|
| 2015 (15.03) | SS.SMu.SMuVS.LhofTtub | Limnodrilus hoffmeisteri, Tubifex tubifex and Gammarus spp. in low salinity infralittoral muddy sediment |
| 2004 (04.05) | SS.SMu.SMuVS.LhofTtub | Limnodrilus hoffmeisteri, Tubifex tubifex and Gammarus spp. in low salinity infralittoral muddy sediment |
| 1997 (97.06) | SS.IMU.EstMu.LimTtub | Limnodrilus hoffmeisteri, Tubifex tubifex and Gammarus spp. in low salinity infralittoral muddy sediment |