Concentration Changes in Cadmium and Lead in Antarctic Coastal Seawater (Ross Sea) During the Austral Summer and Their Relationship with the Evolution of Biological Activity

Abstract

Studies were made of the seasonal evolution of cadmium and lead distribution in the water column of Wood Bay (Ross Sea, Antarctica) during the 1993–94 austral summer. Anodic stripping voltammetry was used to carry out on-site measurements, immediately after the collection and filtration of samples. Before the phytoplankton bloom, the concentrations of both metals were uniform along the water column, with mean values of 0.64 (SD 0.07) and 0.031 (SD 0.006) nmoll−1 for cadmium and lead, respectively. A subsequent depletion in metal concentration was observed in shallow waters. By the end of the season, the surface concentration of cadmium had decreased to about 0.1 nmoll−1. As regards lead, vertical distribution was less affected by season and the mean surface concentration decreased to about 0.01 nmoll−1 over the same period. Results are evaluated in relation to the evolution of biological activity in the area, and are examined and compared with those obtained during a similar study carried out in the Terra Nova Bay area (Gerlache Inlet) 3 years previously.