Abstract

The distributions of the trace metals iron, zinc, copper, nickel, cobalt, and cadmium in the Saguenay fjord have been determined during the spring freshet. Whereas the mean concentrations of copper, nickel, and zinc are only slightly higher than those in the northwest Atlantic Ocean, the levels of cadmium and cobalt are about three to six times higher, and iron up to two orders of magnitude higher, than ocean water. The significant enrichment of all these metals, with the exceptions of zinc and cadmium, in the surface water relative to the intermediate depth water reflects runoff inputs. The concentrations of total and dissolved iron decrease with increasing salinity, but the nonlinearity of the relationships between the metal concentrations and salinity indicates that significant quantities of iron are lost from the water column in the fjord. Except near the head of the fjord, where flocculation and sedimentation processes appear to be removing large quantities of river-borne iron, iron comprises a constant 11% of the suspended particulate matter. The residence time and budget for iron in the larger western basin of the fjord indicate that 47% of the iron that enters the basin is rapidly removed to the underlying sediments.

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