Is practical salinity conservative in the Baltic Sea?

The conductivity-salinity conversion algorithm used for oceanographic measurements of Practical Salinity on the PSS-78 scale is designed for IAPSO Standard Seawater. The application of this formula to a given sample of non-standard seawater does not necessarily result in a constant salinity value when the sample’s conductivity is measured at different temperatures.We have experimentally studied the magnitude of this non-conservative effect of Practical Salinity using a sample of Baltic seawater possessing a density anomaly of about 50 g m−3. The apparent change of salinity observed is at the limit of experimental uncertainty and is not significantly different from the drift of Standard Seawater, which was measured for comparison.