Distribution in ocean
Sodium is the second most abundant element dissolved in seawater. It has a
conservative distribution
that varies only due to differences in evaporation or precipitation in the water
that sank to form intermediate or deep waters in the sea (data).
Concentrations are higher in the Atlantic because that ocean is saltier.
Speciation
Sodium is present in seawater as the Na+ ion.
Residence time
The sodium residence time is from Tracers in the Sea (Broecker, W. S. and Peng,
T.-H., 1982. Eldigo Press, Palisades, NY). It was calculated from
the global average river input.