Trace Element Geochemistry in the Southern Ocean

Summary

Water samples were collected on 2 surveys (1980, 1981) in the Southern Ocean south of South Africa, and these were analyzed for the trace elements copper, zinc and cadmium, in addition to the usual oceanographic parameters (temperature, salinity, dissolved oxygen, phosphate, nitrate and silicate). The results showed that, unlike other areas of the world ocean, there is little evidence that the trace elements follow the systematics of the nutrients. This is ascribed to the low productivity of the area. Lateral advection was found to affect distributions more than vertical processes. The oxygen minimum associated with Circumpolar Deep Water, advected into the region via the Drake Passage, was unexpectedly found to be a layer of minimum Cu concentration. Zinc and Cd showed little variation in the deep water, having values characteristic of those found elsewhere in the world ocean. The copper-silicate ratio was found to be a useful tracer, and was used to infer an input of dissolved silicate from the sediments into the bottom water.