Diffusion of ions in sea water and in deep-sea sediments

The tracer-diffusion coefficient of ions in water, Dj0, and in sea water, Dj∗, differ by no more than zero to 8 per cent. When sea water diffuses into a dilute solution of water, in order to maintain the electro-neutrality, the average diffusion coefficients of major cations become greater but of major anions smaller than their respective Dj∗ or Dj0 values. The tracer diffusion coefficients of ions in deep-sea sediments, Dj,sed., can be related to Dj∗ by Dj,sed. = Dj∗ · αθ2, where θ is the tortuosity of the bulk sediment and a a constant close to one.