Plutonium-239 has been found in over-ocean aerosols in about the same ratio to Strontium-90 as that reported over land. In seawater, Pu-239:Sr-90 ratios are shown to be less than half of those in over-ocean aerosols, confirming geochemical separation of these nuclides in the ocean. It is suggested that the sedimentation of Pu-239 may be more involved with biological processes than has been found for Ce-144 or Pm-147.