transition zone between the northern North Atlantic and the central Arctic Ocean, and to determine the factors controlling Arctic deep-sea biodiversity. • Permanent presence at sea, from surface to depth, for the [...] The Weddell Sea features a rich and diverse ecosystem, complex sea-ice dynamics and intense ocean circulation. The physical and biogeochemical processes that prevail in the central Weddell Sea and the water [...] transition zone between the northern North Atlantic and the central Arctic Ocean, and to determine the factors controlling Arctic deep-sea biodiversity. • Permanent presence at sea, from surface to depth, for the