The megabenthic assemblages of the Vercelli Seamount (North Tyrrhenian Sea).

The megabenthic assemblages of the Vercelli Seamount (North Tyrrhenian Sea) were studied through ROV imaging from 60 to 500 m depth and a peculiar benthos zonation was observed. The shallower rocky peak (60-100 m depth) hosted a very reach coralligenous community characterized, on the top by the kelp Laminaria rodriguezii, by gorgonian assemblages on the southern flank and by sponges-soft corals assemblages on the northern one. On the detritic bottom at the base of the peak, a very dense population of the crinoid Leptometra phalangium was observed. On the edge of the detritic plain, around 180-200 m depth, a ring of the yellow scleractinian coral Dendrophyllia cornigera, mainly dead, was recorded. The rocky slopes from 200 to 500 m depth, covered by a thick iron-manganese crust, were very poorly colonized, mainly by encrusting sponges and serpulids. This research is the first detailed investigation, through ROV imaging, of megabenthic communities living on a Mediterranean seamount, representing therefore a study model for this peculiar ecosystem.