Sea ice influence on benthic community variability in the Alaskan Arctic shelves

Along the Arctic continental shelves epibenthic organisms can be found in high abundance and biomass. Several members of the benthic community constitute key elements of the Arctic food web; as prey of marine mammals, birds and fish (Bluhm & Gradinger 2008). Specifically diving sea ducks, bearded seals, grey whales and walruses feed on benthic organisms. Among the important epibenthic species encountered on the Alaskan Arctic shelves are brittle stars, amphipods, snow crab, hermit crab and shrimp (Bluhm et al. 2009, Ravelo & Konar In Review, Ravelo et al. submitted). Epibenthic communities in the Arctic are dominated by certain taxa over large spatial scales until key environmental drivers interrupt their distribution (Piepenburg 2005, Ravelo et al. submitted). In the Chukchi Sea, echinoderms occur in dense assemblages (several hundred individuals per meter square) and high biomass, up to 30% higher than the highest values reported for echinoderms in the Barents Sea (Ambrose et al. 2001). On the western Alaskan Beaufort shelf epibenthic invertebrates made up to 94% of the total benthic standing stock (Rand & Logerwell 2010).