Vertical distribution of cadmium in marginal seas of the western Pacific Ocean

The vertical distribution of cadmium at four locations in three marginal seas of the western Pacific Ocean are described. Data show that the surface layers at all stations were depleted (< 0.02 nM Cd) and the concentration of Cd increased with depth up to 1.05 nM at 1000–1200 m. Although the shapes of the profiles for the three seas differ significantly, Cd concentrations show strong correlation with those of nitrate and phosphate. Average molar ratios of (3.64 ± 0.02) × 10−4 and (2.50 ± 0.01) × 10−5 (n = 107) were found for d[Cd]/d[PO4] and d[Cd]/d[NO3], respectively. Unlike previous work reported for the eastern Pacific Ocean, intercepts were almost zero (below the detection limits) on the correlation plots for [Cd], [NO3], and [PO4] at the studied locations, and correlation coefficients (Cd vs. NO3 and PO4) for all stations were 0.99 or greater. These data are consistent with the nutrient-like behavior of Cd as has been previously observed and significantly expand the Pacific data base for this trace element.