Seasonal changes in sedimentation of particulate matter and lipid content of zooplankton collected by sediment trap in the Arctic Ocean off Axel Heiberg Island

Summary

Sedimentation of particulate matter measured at a depth of 100 m varied from 0.2 to 6.0 mg dry weight m^-2 d^-1 over approximately monthly intervals between September 1986 and June 1987 on the continental shelf of the western Arctic Ocean north of the Canadian Arctic Islands. Detritus deposited during December and January, the period of maximum sedimentation, contained relatively low amounts of organic carbon and nitrogen (4.0% and 0.5% of dry weight, respectively) with a carbon: nitrogen ratio > 7. Maximum rates of organic carbon and nitrogen sedimentation (0.60 and 0.12 mg m^-2 d^-1, respectively) during February were associated with debris enriched with organic matter (organic carbon and nitrogen content of 17.0% and 3.4% of dry weight, C:N=5). Dry weight of macrozooplankton, predominantly Calanus hyperboreus and Metridia longa, separated from preserved trap contents, equalled or exceeded by up to an order-of-magnitude the weight of sedimented debris. Lipid content of CV and adult female stages of C. hyperboreus decreased from 46%–64% of dry weight in September to 20%–30% in January. Females of C. hyperboreus with lower lipid levels (7% of dry weight) between April and June were probably in a post-reproductive condition.