Annual fluxes of particulate chemical trace compounds during the North-East water polynya experiment

Particulate fluxes of organic marker substances (alkanes, wax esters, pristane, and alkenones) and trace elements (Al, Cd, Cu, Fe, Mn, Ni, and Pb) were determined from identical samples of sediment trap material collected at North East Water Polynya (NEWP) locations E and F in the north-western Greenland Sea. Samples from the East Greenland Shelf were obtained with two sediment traps deployed at 130 m depth over a 331-day period from August 1992 to June 1993 within the NEWP experiment. Particulate fluxes of the chemical tracers showed a pronounced seasonality, which was largely consistent with ice-coverage data. Relative flux pattern exhibited initial maxima during August and September 1992. Fluxes were lowest during winter time (November 1992 to early March 1993), followed by an increase by a factor of 2–5 in mid-March 1993. In contrast, flux of n-alkanes occurred almost entirely in spring 1993. Flux of alkenones was not detectable throughout this experiment. Temporal variations of chemical tracer fluxes at trap location E were similar to those of station F during autumn 1992. Normalization calculations showed that lithogenic material was an important source for trace element fluxes, with an estimated lithogenic fraction of the bulk material flux increasing from autumn to spring. A non-lithogenic flux component was observed for Cd throughout the time of deployment. The chemical data indicate that during the peak flux periods a large proportion of the sinking particles consisted of fresh material. Differences in the patterns of the bulk material flux and the chemical tracer fluxes indicate that there must have been a substantial difference between autumn and spring in the gross chemical composition of the sinking material.