PHOSPHORUS CADMIUM CYCLING IN THE NORTHEAST TASMAN SEA, 35-40-DEGREES-S

The distributions of cadmium (Cd) and phosphate (P) in the northeast Tasman Sea between 35 and 40-degrees-S have been studied. These are the first reported measurements of Cd in subtropical waters of the South Pacific. At offshore locations, the vertical profile of Cd was intermediate between those typical of the North Atlantic and the North Pacific oceans and was highly correlated with P, confirming trends observed in northern hemisphere waters. Deep-water Cd-P ratios were consistent with 'global' trends established in northern latitudes. Surface-water Cd in offshore waters varied between 0.02 and 0.05 nmol kg-1 depending on nutrient levels. In the upwelling region at the extreme north of New Zealand, Cd varied inversely with P, indicating changes in the selectivity of Cd uptake with P. Continental shelf waters over the Challenger Plateau west of New Zealand were elevated by almost an order of magnitude, perhaps reflecting anthropogenic influences.