Cadmium, copper, lead and zinc on transects through Arctic and Eastern Atlantic surface and deep waters
Pohl, C.; Kattner, G.; Schulz-Baldes, M. (1993). Cadmium, copper, lead and zinc on transects through Arctic and Eastern Atlantic surface and deep waters. J. Mar. Syst. 4(1): 17-29
In: Journal of Marine Systems. Elsevier: Tokyo; Oxford; New York; Amsterdam. ISSN 0924-7963; e-ISSN 1879-1573, more
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| Authors | | Top |
- Pohl, C.
- Kattner, G.
- Schulz-Baldes, M.
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| Abstract |
A total of 230 surface and 70 deep water samples was collected during several transects in the European Arctic and the East Atlantic. The distribution of Cd in surface waters of the Arctic is associated with the nutrient regime and the primary production. In the euphotic zone about 80% of dissolved Cd is eliminated by phytoplankton corresponding to a deltaCd:deltaPO4 ratio of 1.7 × 10-4. In addition, there is a reverse linear relationship with Chlorophyll a. Regional fluctuations could be demonstrated: the highest Cd concentrations (0.25 nmol·kg-1) were on the East Greenand shelf, by a factor of 3-4 lower values in the frontal systems, and medium levels (0.1 nmol·kg-1) were observed in the mixing waters of the Greenland Sea gyre. Eastern Atlantic Cd concentrations 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 contrast Atlantic deep water values at the nutrient maxima were 2-3 times higher than in the Arctic study areas. Good correlations between Cd/Phosphate with a mean slope of 1.2 × 10-4 were found for the deep water stations in the East Atlantic Basins. Lead showed the lowest dissolved concentrations in waters of the ice covered region of the East Greenland shelf (0.02 nmol·kg-1) and in the South Atlantic (0.05 nmol·kg-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. Regional averages of the Cu concentrations in Arctic areas fluctuate between 4 nmol·kg-1 on the East Greenland shelf and 1 nmol·kg1 in the mixing 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 between Cu/SiO2 with a slope of 0.028 nM/µM. Zn concentrations in surface waters of the Arctic region may have one source in the atmospheric input, as shown by high Zn concentrations of sea ice (1-13 nmol·kg-1) from the ice covered region. Lowest values (0.3-0.8 nmol·kg-1) were determined in 1989 between 35°S and 25°N in East Atlantic surface waters. The data for the trace metals are discussed in the context of the hydrography and the nutrient situation of the two areas under investigation. |
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