Effects of seawater pH and calcification rate on test Mg/Ca and Sr/Ca in cultured individuals of the benthic, calcitic foraminifera Elphidium williamsoni

► Rayleigh fractionation is not the predominant control on test Sr and Mg. ► Test Sr and Mg do not vary significantly between pH treatments. ► Calcification rate is not a significant influence on test Sr or Mg.