Trophic relationships of the sea ice meiofauna in Frobisher Bay, Arctic Canada

Summary

A distinct fauna consisting mainly of nematodes, harpacticoid and cyclopoid copepods, rotifers, turbellarians and polychaete larvae, inhabits the lower levels of the sea ice in Frobisher Bay. Similar faunas are found throughout circumpolar regions. Thirteen taxa of the Frobisher Bay ice fauna were entirely herbivorous. Their food consisted of 26 genera of algae dominated by Chlamydomonas, Nitzschia, Navicula and Chaetoceros. There was a clear tendency to feed on the most abundant ice algae, hence little evidence of selective feeding. High algal food concentrations in the ice (estimated at 5000 μg C/l) were in sharp contrast with the scant nourishment available from phytoplankton under the ice (8 μg C/l) from mid-winter until the start of the summer bloom. Algal stocks and estimated productivity rates indicate that ice meiofaunal food requirements may be met by the ice algae. All the major ice meiofaunal species are well adapted to feeding within the ice. All are small enough to enter brine channels and secure particulate prey from surfaces within confined spaces. The ice meiofaunal species are major consumers of the ice algae and therefore important links in the transfer of energy from the ice to pelagic and benthic predators, including fishes, birds and mammals.