Cadmium in the southwest Pacific Ocean two factors significantly affecting the CdPO 4 relationship in the ocean

• Published in: Marine chemistry Vol. 54; no. 1; pp. 55 - 67
• Main Authors: Kudo, Isao, Kokubun, Haruyo, Matsunaga, Katsuhiko
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 1996
• ISSN: 0304-4203; 1872-7581
• DOI: 10.1016/0304-4203(95)00100-X

Vertical profiles of dissolved Cd were determined in the southwest Pacific Ocean, which includes the Tasman Sea, the Solomon Sea, and the Coral Sea. Cd shows a nutrient type distribution, but weakly correlates with phosphate compared to the North Pacific Ocean when all data are plotted. The Cd PO 4 ratio in surface layer is < 0.1 nM μM and the ratio in the intermediate and deep water shows an increase approaching the Pacific value of ~ 0.3 nM μM . The Cd PO 4 ratio in the regeneration process has been estimated using an AOU (apparent oxygen utilization) respiration model. This ratio is affected by that in surface layer, so deep water receives a regeneration flux with a low Cd PO 4 ratio. The preformed Cd and phosphate as estimated by the AOU relation are low in the surface layer and high in the deep layers. The intermediate water is a mixture of surface water and Antarctic Intermediate Water (AAIW). The characteristic CdPO 4 relationship in this area would be a consequence of mixing with two water masses which have different original Cd PO 4 ratios. The factors affecting the CdPO 4 relationship in the world ocean are physical mixing and biological cycling, based on the results of the southern Pacific Ocean.