Elpidia glacialis

Elpidia glacialis is a sea cucumber belonging to the family Elpidiidae. It lives on the deep seabed of the Arctic Ocean, the Barents Sea, the Kara Sea, and the North Atlantic Ocean. Swedish zoologist Johan Hjalmar Théel first described the species in 1876, after collecting specimens during an expedition with explorer Adolf Erik Nordenskiöld that aimed to find the Northeast Passage.

In the Greenland Sea, this sea cucumber has been found on the lower continental slope at around 2,700 meters deep, sharing its habitat with the sea lily Bathycrinus sp., the sea spider Ascorhynchus abyssi, the brachiopod Waldheimia cranium, and the zoanthid Epizoanthus sp. The sea lily and the sea cucumber were the most common animals there, possibly because echinoderms can adjust their feeding methods based on available food. In the central Arctic Ocean, most large bottom-dwelling animals stayed within specific depth ranges, but E. glacialis and the predatory swimming snail Limacina helicina were exceptions.

In the Canada Basin, the seabed depth was about 3,800 meters. In a canyon in the western Greenland Sea at roughly 3,200 meters deep, E. glacialis sometimes reached densities of up to sixty individuals per square meter. It feeds on organic matter in the sediment, and its abundance likely reflects differences in how much food is available there.