| The concentrations of certain trace elements incorporated into the calcium carbonate shells of foraminifera can provide information about the seawater in which they live. In order to use these trace element concentrations to reconstruct ocean conditions in the past, they must be calibrated by comparing the chemistry of recently living foraminifera to measurements of seawater properties. This thesis utilizes a set of high quality sediment cores from the Florida Straits to calibrate five trace element paleoceanographic proxies (Mg/Ca, Sr/Ca, Li/Ca, Cd/Ca and Zn/Ca) in five species of benthic foraminifera. The Mg/Ca ratio in the shell increases with increasing seawater temperature, and may also be influenced by the seawater carbonate ion concentration. The Mg/Ca - temperature relationship may be improved by dividing Mg/Ca by Li/Ca. Sr/Ca is complicated by several environmental variables. Cd/Ca is proportionate to seawater Cd, which is correlated with the labile nutrient phosphate. Zn/Ca, in at least one species, is proportionate to seawater Zn, which is correlated with the refractory nutrient silica. The trace element geochemistry of benthic foraminifera provides a valuable set of tools to the field of paleoceanography. |
