EUNIS habitat classification 2012 amended 2019 > A - Marine habitats > A5 - Sublittoral sediment > A5.3 - Sublittoral mud > A5.37 - Deep circalittoral mud > A5.372 - Foraminiferans and Thyasira spp. in deep circalittoral soft mud

Foraminiferans and Thyasira spp. in deep circalittoral soft mud

English name: Foraminiferans and Thyasira spp. in deep circalittoral soft mud

Quick facts

EUNIS habitat type code A5.372
Bern Convention Included in a Resolution 4 habitat type at a higher level (A5)

Description (English)

In deep water and soft muds of Boreal and Arctic areas, a community dominated by foraminiferans and the bivalve Thyasira sp. (e.g. T. croulinensis and T. pygmaea) may occur (Thorson 1957; Künitzer et al. 1992). Foraminiferans such as Saccammina, Psammosphaera, Haplophragmoides, Crithionina and Astorhiza are important components of this community with dead tests numbering thousands per m2 (see Stephen 1923; McIntyre 1961) and sometimes visible from benthic photography (Mackie, Oliver & Rees 1995). It is likely that a community dominated by Astorhiza in fine sands in the Irish Sea may be another distinct biotope (E.I.S. Rees pers. comm. 2002). Polychaetes, e.g. Paraonis gracilis, Myriochele heeri, Spiophanes kroyeri, Tharyx sp., Lumbrineris tetraura, are also important components of this biotope. These communities appear to have no equivalent on the continental plateau further south (Glemarec 1973) but are known from the edge of the Celtic Deep in the Irish Sea (Mackie, Oliver & Rees 1995). The benthos in these offshore areas has been shown to be principally Foraminifera and similar, rich communities may exist in Scottish sealochs (McIntyre 1961). Communities from yet deeper (northern) waters at the extremes of the North Sea may be reminiscent, although dissimilar to A5.372 (see Pearson et al. 1996) reflecting a higher proportion of silt/clay. A fully Arctic version of this biotope has also been described (Thorson 1934, 1957) although it should be noted that Jones (1950) considered this Boreal foraminiferan community to be part of a 'Boreal Deep Mud Association'.
Situation: This community typically occurs in water deeper than 100 m in the northern North Sea (Knitzer et al. 1992) and have been referred to as 'Foraminifera communities' by other workers (e.g. Stephen 1923; Thorson 1957; McIntyre 1961).

Source: EUNIS habitat classification

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Species mentioned in habitat description

Invertebrates Myriochele heeri
Invertebrates Spiophanes kroyeri
Species scientific name English common name Species group
Myriochele heeri Invertebrates
Spiophanes kroyeri Invertebrates

Other classifications

Classification Code Habitat type name Relationship type
Marine Habitat Classification Britain/Ireland 0405 SS.SMu.OMu.ForThy Foraminiferans and <I>Thyasira</I> sp. in deep circalittoral fine mud source
CORINE Land Cover 5.2.3. Sea and ocean n/a
For relation to plant communities (syntaxa), see Vegetation types

History

Classification Code Habitat type name Relationship type
EUNIS Habitat Classification 200410 A5.372 Foraminiferans and Thyasira spp. in deep circalittoral soft mud same
EUNIS Habitat Classification 200308 A4.742 Foraminiferans and Thyasira spp. in deep circalittoral soft mud same
EUNIS Habitat Classification 200202 A4.742 Foraminiferans and Thyasira sp. in deep circalittoral soft mud same
EUNIS Habitat Classification 199910 A4.712 Foraminiferans and Thyasira sp. in deep circalittoral soft mud same
MNCR BioMar 97.06 (Britain & Ireland) COS.ForThy Foraminiferans and Thyasira sp. in deep circalittoral soft mud same
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