Depth distributions of copper in the water column and interstitial waters of an Alaskan fjord

The concentrations and fluxes of copper in the deep basin of an Alaskan fjord were found to be controlled principally by reactions within the surface sediments and exchanges across the sediment-water interface. Copper is removed from the deep water onto particulates and transported to the sediment surface. It is remobilized within a surface sediment zone and about 20% of that brought to the sediments is returned to the water column. Copper is removed from interstitial waters, probably by precipitation as sulfides. Reaction rates in sediments are one to three orders of magnitude greater than those in the water column and the remobilization and removal reactions in these sediments occur in thin zones close to the sediment-seawater interface.