The densities of western Indian Ocean, Red sea and eastern Mediterranean surface waters

Abstract

Direct measurements of density were made on 176 surface samples collected in 1979 from the western Indian Ocean, Red Sea, and eastern Mediterranean Sea. The measurements were compared with the values calculated from the conductance salinity in order to evaluate the influence on the density of the partial molar volumes and the partial molar conductivity of the ions whose ionic ratios differ from their values in Standard Seawater. It is concluded that the differences between the measured and calculated densities are practically constant in vast geographical areas, corresponding to the various water masses of the World Ocean. An exception is the Red Sea, where the differences vary rapidly from the south to the north. These differences are always negative for the surface waters studied and can be correlated linearly to the variation of conductivity salinity. They are only partially explained by the total alkalinity and total carbon dioxide changes in these waters.