A strong positive relationship between the molar P/Fe ratio in fresh hydrothermal Fe ferrihydrite precipitates and seawater-dissolved phosphate has been demonstrated using samples from the Atlantic and Pacific Oceans. We ascribe this relationship to scavenging of dissolved phosphate from seawater during the formation of hydrothermal Fe-rich particles above hydrothermal vents. In contrast, molar V/Fe ratios in hydrothermal particles are inversely correlated with dissolved phosphate. These results indicate that inter-ocean variations in dissolved phosphate control the P/Fe and V/Fe ratios in hydrothermal Fe precipitates, one of the precursors of metalliferous sediment. ¿ 1998 American Geophysical Union