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  4. MD6-214 - Foraminifères et Thyasira spp. dans de la vase meuble du circalittoral du large en Atlantique
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MD6-214 - Foraminifères et Thyasira spp. dans de la vase meuble du circalittoral du large en Atlantique

Foraminiferans and Thyasira spp. in Atlantic offshore circalittoral soft mud
MD6-213 - Tapis de Ampharete falcata et Parvicardium pinnulatum (anciennement Parvicardium ovale) sur sédiment vaseux du circalittoral du large en bordure de mers profondes stratifiées en Atlantique
MD6-215 - Styela gelatinosa, Pseudamussium peslutrae et ascidies solitaires sur sédiment vaseux abrité du circalittoral du large en Atlantique

Classification des habitats EUNIS 2022

Descriptif de l'habitat

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 toMD6-214 (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).

Bibliography

European Topic Centre on Biological Diversity 2022. EUNIS marine habitat classification 2022 including crosswalks. Table Excel. (Source)