Zn/Si records in diatom opal from Prydz Bay, East Antarctica

•The difference of Zn/Si records between continental shelf and slope could be attributed to the changes of Zn2+ via upwelling or circulation.•Zn/Si proxy could be a signal of marine productivity on the continental shelf of Prydz Bay.•The down core profile of Zn/Si records shows increased tendency of marine productivity during the recent century.

The Zn/Si records of diatom opal from Prydz Bay were investigated. The results show that the Zn/Si ratios range from 8 to 53 μmol mol− 1. The ratio from the continental slope is higher than those from the shelf. The difference in Zn/Si records could be attributed to the change of bioavailable Zn via the upwelling of Zn2 +-rich deep water or the influence of oceanic water on the slope. However, phytoplankton productivity influences Zn/Si records on the continental shelf. Increased productivity leads to elevated Zn-pumping, and eventually to higher Zn/Si ratio in diatom opal. In this case, it is suggested that Zn/Si proxy could be a signal of marine productivity on the continental shelf of Prydz Bay. The down core profile of Zn/Si records shows an increase in marine productivity over the last century.