Distribution and biomass transport of ice amphipods in drifting sea ice around Svalbard

The overall mean biomass for flats (0.30±0.05 g m−2) and ridges (1.64+0.46 g m−2) were used to calculate ice-associated biomass transport based on revised mean annual ice flux through Fram Strait (662,000 km2 yr−1) and into the Barents Sea (total 228,000 km2 yr−1). About 478×103 t WW (57×103 t C) of ice amphipods are transported annually through Fram Strait and 194×103 t WW (23×103 t C) into the northern Barents Sea, implying that 71% of the amphipod biomass in drifting sea ice passes through Fram Strait and 29% enters the Barents Sea. Climate induced reduction in ice thickness and extent will likely decrease this southward biomass transport, and thus the current carbon input of about 80×103 t C yr−1 into these marginal seas. Ice amphipod populations probably cannot be sustained if the summers become ice free in the Arctic Ocean, and particularly reduction of multi-year ice in the Arctic Ocean will affect long-lived species such as Gammarus wilkitzkii.