Silver in the far North Atlantic Ocean

Total (unfiltered) silver concentrations in higher latitudes of the North A tlantic (52-68 degrees N) are reported for the second Intergovernmental Oce anographic Commission (IOC) Global Investigation of Pollutants in the Marin e Environment (GIPME) baseline survey of 1993. These silver concentrations (0.69-7.2 pM) are oceanographically consistent with those (0.24-9.6 pM) pre viously reported for lower latitudes in the eastern North and South Atlanti c (Flegal et al,, 1995). However, surface ( less than or equal to 200 m) wa ter concentrations of silver (0.69-4.6 pM) in the northern North Atlantic w aters are, on average, ten-fold larger than those (0.25 pM) considered natu ral background concentrations in surface waters of the central Atlantic. In contrast, variations in deep far North Atlantic silver concentrations are associated with discrete water masses. Consequently, the cycling of silver in the far North Atlantic appears to be predominantly controlled by externa l inputs and the advection of distinct water masses, in contrast to the nut rient-like biogeochemical cycling of silver observed in the central Atlanti c and Pacific oceans. (C) 1999 Elsevier Science Ltd. All rights reserved.