Page 41 - living-ice

PHOTO: Shawn Harper, UAF
Sea ice as an
inverted seabed
Most kinds of organisms that live in the network of channels and pockets in the sea ice also live on the seabed. That is because the sea ice and the seabed have something in common. The sea ice and seabed are both solid surfaces that organisms can attach themselves to and both have three-dimensional channels that organisms can crawl through. The channel walls of the sea ice are made from ice crystals, while those in the seabed consist of sand grains. Examples of organism types that live in both the sea ice and at the seabed are amphipods, roundworms, atworms, benthic copepods and rotifers (more commonly called wheel animals). Particularly above shallow water, many benthic organisms utilise the sea ice as a pantry. Vice versa, some species in the fjords of Svalbard normally live in the ice, but can spend the summer on the shallow bottom. The amphipod Gammarus wilkitzkii is one such example.