Variations in the Zn/Si record over the Last Interglacial Glacial Transition

We examined the zinc content of diatom frustules as an indicator of past changes in surface seawater Zn 2+ concentration. Zn/Si data of samples from three cores located in the South Atlantic sector of the Southern Ocean spanning the last interglacial‐glacial transition are presented. Changes in the Zn/Si record are linked to changes in the surface water Zn 2+ concentration. The source of variation in Zn 2+ concentration appears to be via changes in deep water upwelling and circulation. We rule out changes in phytoplankton productivity and aeolian dust input as a source of variation in the Zn/Si record. Likewise, the Zn/Si data are not linked to shifts in the diatom species composition of the sediment or sediment preservation effects. The Zn/Si results presented do not support the zinc hypothesis. There is no link between the uptake of CO 2 by phytoplankton, as inferred from the δ 13 C record, and the Zn/Si record.