Reprint of 'On and off the beaten track: Megafaunal sessile life and Adriatic cascading processes'

Abstract

Valuable megafaunal sessile assemblages in the southern Adriatic basin present a western–eastern asymmetric distribution. This is particularly evident when considering cold-water coral (CWC) communities, with most diverse and abundant live corals to be found along the western side. On the contrary, only spotty occurrences are documented in the eastern side and at times only in a sub-fossil state. We hypothesize that this asymmetry might derive from differential exposure of the Adriatic floor to polarized hydrological processes. In such a perspective, vigorous albeit a-periodical flushing of deep-sea bottoms at times of cascading processes could be beneficial to sessile deep-sea benthic communities by reinforcing the North Adriatic Dense Water (NAdDW), contrasting excess silting and by enhancing the trophic web. Although no experimental evidence has been yet produced to test this hypothesis, it gains some support by the observation that CWC are flourishing in the general area of the Bari Canyon and adjacent bottoms flushed by dense shelf water (DSW) cascading while they are much less developed on the basin's opposite side, unaffected by this phenomenon.