Seasonal variation in the copper complexing capacity of Port Hacking

Abstract

The copper complexing capacity (CuCC) of waters at the entrance to Port Hacking estuary, Australia, was monitored approximately daily from February to November 1984. Biological and hydrological parameters collected from this area since 1942 provide a wealth of historical data to aid in the interpretation of the results. From May to August, the CuCC values averaged about 5 nM, with occasional high values (up to 17 nM) attributable to terrestrial runoff following heavy rainstorms. In mid-October, CuCC values up to 56 nM were attributable to a phytoplankton bloom that resulted from the intrusion of nutrient-rich slope waters onto the continental shelf. These intrusions of slope water seem to be driven onto the continental shelf by the approach of the East Australian Current and its associated eddy field. The approach of an eddy coincided with a secondary maximum in the CuCC (30 nM) that occurred in mid-April. The CuCC of Port Hacking is dominated by processes originating outside the estuary; Port Hacking cannot therefore be a significant source of organic ligands to coastal waters.