Mn, Ni, Cu, Zn and Cd in the Western North Atlantic

Abstract

The concentrations of Mn, Ni, Cu, Zn and Cd have been determined on surface and deep water samples from the western North Atlantic. The results from a single vertical profile are compared to published results from the North Pacific and interpreted with respect to the hydrographie characteristics of both oceans. Cd, Zn and Ni have nutrient-type distributions in both oceans. They are depleted in surface waters, increase rapidly across the thermocline, then increase or decrease only slightly with depth. The North Atlantic deep waters at depths of 1 to 3 km have average concentrations of Cd, Zn and Ni equal to 0.29, 1.5 and 5.7 nmol kg−1, respectively; values substantially lower than their corresponding values in the North Pacific at similar depths of 0.94, 8.2 and 10.4 nmol kg−1. Cu concentrations increase gradually with depth in both oceans, with a North Atlantic deep water (1 to 3 km) average value of 1.7 nmol kg−1 relative to 2.7 nmol kg−1 at similar depths in the North Pacific. Mn concentrations decrease with depth through the thermocline with deep North Atlantic values on the order of 0.6 nmol kg−1.