CADMIUM, COPPER, LEAD AND ZINC ON TRANSECTS THROUGH ARCTIC AND EASTERN ATLANTIC SURFACE AND DEEP WATERS

A total of 230 surface and 70 deep water samples was collected during several transects in the European Arctic and the East Atlantic. The di stribution of Cd in surface waters of the Arctic is associated with th e nutrient regime and the primary production. In the euphotic zone abo ut 80% of dissolved Cd is eliminated by phytoplankton corresponding to a DELTACd:DELTAPO4 ratio of 1.7 x 10(-4). In addition, there is a rev erse linear relationship with Chlorophylla. Regional fluctuations coul d be demonstrated: the highest Cd concentrations (0.25 nmol.kg-1) were on the East Greenland shelf, by a factor of 3-4 lower values on the f rontal systems, and medium levels (0.1 nmol.kg-1) were observed in the mixing waters of the Greenland Sea gyre. Eastern Atlantic Cd concentr ations are sometimes near the detection limit (< 0.02 nmol.kg-1) and 5 -20 times lower in surface waters than in the Arctic study areas. In c ontrast Atlantic deep water values at the nutrient maxima were 2-3 tim es higher than in the Arctic study areas. Good correlations between Cd /Phosphate with a mean slope of 1.2 x 10(-4) were found for the deep w ater stations in the East Atlantic Basins. Lead showed the lowest diss olved concentrations in waters of the ice covered region of the East G reenland shelf (0.02 nmol.kg-1) and in the South Atlantic (0.05 nmol.k g-1), with increases by 10-20 times in the region of the Greenland Sea gyre and 3-5 times in the region of the westerlies. Concentrations in sea ice were 70 times higher than in the surrounding water masses. Re gional averages of the Cu concentrations in Arctic areas fluctuate bet ween 4 nmol.kg-1 on the East Greenland shelf and 1 nmol.kg-1 in the mi xing waters of the Greenland Sea gyre. Interannual Cu distribution was rather constant in Arctic and Atlantic surface waters. Seven vertical profiles in Eastern Atlantic basins showed a strong correlation betwe en Cu/SiO2 with a slope of 0.028 nM/muM. Zn concentrations in surface waters of the Arctic region may have one source in the atmospheric inp ut, as shown by high Zn concentrations of sea ice (1-13 nmol.kg-1) fro m the ice covered region. Lowest values (0.3-0.8 nmol.kg-1) were deter mined in 1989 between 35-degrees-S and 25-degrees-N in East Atlantic s urface waters. The data for the trace metals are discussed in the cont ext of the hydrography and the nutrient situation of the two areas und er investigation.