47 - Habitats at the Rockall Bank Slope Failure Features, Northeast Atlantic Ocean

Abstract

This chapter presents the preliminary findings of research undertaken to provide information on the extent and distribution of Annex 1 geogenic reef habitat, pertaining to offshore morphological features such as escarpments, submarine canyons and channels. The Rockall Bank forms part of the Rockall Plateau located in the Northeast Atlantic Ocean, west of Ireland, occurring in water depths from 200 m and extending to 3,000 m in the Rockall Trough, the adjacent deep-water basin. Previous studies examining the geomorphology of the eastern Rockall Bank have described the presence of extensive broadscale (>10 km) “slope failure features, e.g., scarps and channels.” Geomorphic features identified included seabed scarps, overhangs and horizontal ledges, vertical rock walls, and pinnacles. Benthic habitats identified were characterized by (i) the framework reef-building cold-water coral Lophelia pertusa occurring on overhangs, boulders, and drop-stone pavements, (ii) gorgonians, encrusting sponges, soft corals, and black corals occurring on pinnacles and overhangs, and (iii) corallimorphs, desmospongiae, encrusting sponges, and scleractinia occurring on vertical rock walls and horizontal ledges.