Mg/Ca ratios measured on 50-60 shells of the planktonic foraminifera species Globigerinoides ruber alba. Shells were picked from the 250-300 micrometer size fraction and occasionally from the 200-250 if not enough specimens were available from the 250-300 fraction. Sea water temperature estimates were calculated using the following equation T = ln(Mg/Ca/0.30)/0.089 (doi:10.1126/science.289.5485.1719). Stable oxygen isotope ratios were measured on planktonic (Globigerinoides ruber alba) and benthic foraminifera (Cibicides wuellerstorfi). 25-30 shells from the 250-300 micrometer size fraction were used for each measurement on planktonic foraminifera and 5-8 specimens from the 300-355 micrometer size fraction for benthic foraminifera.