The epilithozoan fauna associated with Quaternary FeMn crustgrounds sampled off Capri and Li Galli Islands is described. During the Quaternary, the interplay among the tectonically induced topography, seacurrent patterns, and the changing physical-chemical properties of the water column promoted conditions favouring FeMn oxide accumulation. In the samples dredged between 510263 m depth (DRA 7), 207201 m depth (DRA 5) and 35865 m depth (DRA 4), where the FeMn coating covers all rock surfaces, the distribution of the epilithozoan taxa is polarized: on the upper smooth surface of the crustgrounds the most abundant inhabitants are foraminifers, while on the lower rough surface corals, bivalves, bryozoans and brachiopods occur. Sponges are mainly able to bioerode the rough lower surfaces. Samples are riddled by boring ichnogenera including Entobia and Maeandropolydora. FeMn oxide precipitation is still active today as shown by the frontal shield preservation of the bryozoan Puellina cf. pseudoradiata Harmelin and Aristegui, 1988, where it is possible to identify different stages of accretion. Botryoidal ongoing accretion is evident only in some taxa, namely Bryozoa and Polychaeta species, and Foraminifera morphotypes, which appear to keep pace with precipitation when it occurs.
Epilithozoan fauna associated with ferromanganese crustgrounds on the continental slope segment between Capri and Li Galli Islands (Bay of Salerno, Northern Tyrrhenian Sea, Italy).
RASPINI A
2005
Abstract
The epilithozoan fauna associated with Quaternary FeMn crustgrounds sampled off Capri and Li Galli Islands is described. During the Quaternary, the interplay among the tectonically induced topography, seacurrent patterns, and the changing physical-chemical properties of the water column promoted conditions favouring FeMn oxide accumulation. In the samples dredged between 510263 m depth (DRA 7), 207201 m depth (DRA 5) and 35865 m depth (DRA 4), where the FeMn coating covers all rock surfaces, the distribution of the epilithozoan taxa is polarized: on the upper smooth surface of the crustgrounds the most abundant inhabitants are foraminifers, while on the lower rough surface corals, bivalves, bryozoans and brachiopods occur. Sponges are mainly able to bioerode the rough lower surfaces. Samples are riddled by boring ichnogenera including Entobia and Maeandropolydora. FeMn oxide precipitation is still active today as shown by the frontal shield preservation of the bryozoan Puellina cf. pseudoradiata Harmelin and Aristegui, 1988, where it is possible to identify different stages of accretion. Botryoidal ongoing accretion is evident only in some taxa, namely Bryozoa and Polychaeta species, and Foraminifera morphotypes, which appear to keep pace with precipitation when it occurs.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
