COPPER COMPLEXATION IN THE SURFACE SEAWATER OF TERRA-NOVA BAY (ANTARCTICA)

Speciation of copper in the surface seawater of Terra Nova Bay is studied by Differential Pulse Anodic Stripping Voltammetry using samples collected during the 1987-88, 1988-89 and 1989-90 Italian expeditions. Total copper concentration ranges between 0.5 and 4.8 nM and shows uniform spatial distribution without evident differences between the three campaigns. The mean value for the labile fraction is 4% of the total for the first two expeditions, while it is below the detection limit for the last one. Results show the presence of two classes of ligands, one stronger (mean concentration 1.5 nM) which shows considerable variability due to seasonal and spatial factors, and one weaker (mean concentration 31 nM, average conditional stability constant 2.8x10(8) M-1) which shows homogeneous distribution in the studied area.