Distribution of Gryphus vitreus (Born, 1778) (Brachiopoda) on transect P2 (Continental margin, French Mediterranean coast) investigated by submersible

Direct observations by submersible are recorded on a Provence transect, between 88 to 603 m. On the Bathyal detritic sand biocoenosis, characterized by the brachiopod Gryphus vitreus, extending from the shelf edge (103 m) down to 260 m, they corroborate the five distributional density zones of this...

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Bibliographic Details
Published in:Scientia marina 1991-01, Vol.55 (2), p.385-388
Main Authors: Emig, C C, Garcia-Carrascosa, MA
Format: Article
Language:English
Subjects:
Gryphus vitreus
Marine
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Summary:Direct observations by submersible are recorded on a Provence transect, between 88 to 603 m. On the Bathyal detritic sand biocoenosis, characterized by the brachiopod Gryphus vitreus, extending from the shelf edge (103 m) down to 260 m, they corroborate the five distributional density zones of this brachiopod (in density, but not for all their bathymetric limits), previously estimated from dredging data, and the environmental factors responsible for this distribution. Nevertheless, the two deepest density zones have quite different bathymetric limits, i.e. Zone 4: 151-245 m (previously estimated 150-200 m), and Zone 5: 245-260 m (estimated 200-250 m). Near-bottom currents are directly responsible for the density zone extension and depth range of this biocoenosis, which corresponds to the intermediate Mediterranean water layer. The currents move perpendicular to the slope and their strongest velocity occurs over the offshore-shelf where the highest brachiopod density is recorded; however, according to the larger extension of Zone 4, the currents have a larger influence downwards than previously expected. (DBO)
ISSN:0214-8358