A. - Mollusques testacés (Macrofaune)/ Testaceous mollusks (macrofauna )

• Published in: Géologie Méditerranéenne
• Main Authors: Rosso, Jean-claude, Templeton, R.S.M., Desprat, R.
• Format: Article in Journal/Newspaper
• Language: French
• Published: aa : Éditions de l'Université de Provence 1979
• Subjects: Malacocoenoses; Tunisie; Quaternaire.; Evolution des peuplements; Ecologie; Macrofaune; Mer Pélagienne; archeo; geo; Arctica islandica
• Online Access: https://doi.org/10.3406/geolm.1979.1080; https://www.persee.fr/doc/geolm_0397-2844_1979_num_6_1_1080

The ecological study of the Kerkennah Plateau showed 3 environmental groups : 1) those living in the Posidonia thickets 2) those in the Caulerpes and Cymodocea prairies 3) those in the sediments. There appears to be a particular molluscan stock characteristic or preferential to each of these biotopes, but overall differences appear in the unequal proportion of Gasteropods (epiphytes) to Bivalves (endopsammics). Further studies of dredged and cored sea bottom samples at several points in the Pelagian Sea extended the investigation to the deeper zones (lower infralittoral, circa littoral, and bathyal). The malacologie contents of the cores showed a previous extension of the littoral vegetal formations (prairies and thickets) far beyond their present limits the exocentric migration of these formations towards the present coast thus showed the encroachment of the sea during the Versilian transgression. At the same time the special composition of the Wurmian thanatocoenoses was settled, and underlines the biostratigraphic and palaeoclimatic value of significant species (Pseudamussium septemradiatum, Acanthocardia echinata, Calliotropis ottoi.). The presence as indicated by one of the cores (KS 128) of Arctica islandica in the Wurmian deposits of the Pelagian Sea can only suggest or hint at an answer to the question as to whether (and in what conditions) the Cyprine and the boreoceltic form that followed passed the Sicilian-Tunisian saddle during the last ice-age. L'étude écologique du plateau des Kerkennah conduit à distinguer 3 types de peuplements : 1) les peuplements de l'herbier de Posidonies 2) les peuplements des pelouses à Caulerpes et à Cymodocées 3) les peuplements du sédiment. Ils recèlent un stock particulier de Mollusques caractéristiques ou préférentiels de chacun de ces biotopes, mais les différences apparaissent globalement dans l'inégale proportion des Gastropodes (épiphytes) et des Bivalves (endopsammiques). L'analyse, tentée en second lieu, de quelques dragages et sondages effectués en ...