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Marine Habitat Classification


Description of biotope or habitat type

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   Limnodrilus hoffmeisteri, Tubifex tubifex and Gammarus spp. in low salinity infralittoral muddy sediment


Habitat (physical) 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

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.SMu.SMuVS.LhofTtub <I>Limnodrilus hoffmeisteri</I>, <I>Tubifex tubifex</I> and <I>Gammarus</I> spp. in low salinity infralittoral muddy sediment

  • 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 Heterochaeta costata. 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 NeoGam 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
Marenzelleria wireni 3 21 21-40 %
Limnodrilus hoffmeisteri 78 Common 1011 61-80 %
Tubifex tubifex 19 91 41-60 %

Similar biotopes

SS.SMu.SMuVS.OlVS
LhofTtub is similar to OlVS however the latter lacks the freshwater element.

SS.SSa.SSaVS.NintGam
NintGam may be found in conjunction with LhofTtub, although it lacks appreciable numbers of oligochaetes.

Biotope history

Classification Habitat code
97.06 IMU.LimTtub

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