The equation of state of lakes

Frank J. Millero

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


In recent years, a number of workers have studied the stability of deep lakes such as Lake Tanganyika, Lake Baikal and Lake Malawi. In this paper, the methods that can be used to determine the effect that the components of lakes have on the equation of state are examined. The PVT properties of Lakes have been determined by using apparent molal volume data for the major ionic components of the lake. The estimated PVT properties (densities, expansibility and compressibilities) of the lakes are found to be in good agreement with the PVT properties (P) of seawater diluted to the same salinity. This is similar to earlier work that showed that the PVT properties of rivers and estuarine waters could also be estimated from the properties of seawater. The measured densities of Lake Tanganyika were found to be in good agreement (± 2 x 10-6 g cm-3) with the values estimated from partial molal properties and the values of seawater at the same total salinity (S(T) = 0.568‰). The increase in the densities of Lake Tanganyika waters increased due to changes in the composition of the waters. The measured increase in the measured density (45 x 10-6 g cm-3) is in good agreement (46 x 10-6 g cm-3) with the values calculated for the increase in Na+, HCO3-, Mg2+, Ca2+ and Si(OH)4. Methods are described that can be used to determine the conductivity salinity of lakes using the equations developed for seawater. By combining these relationships with apparent molal volume data, one can relate the PVT properties of the lake to those of seawater.

Original languageEnglish (US)
Pages (from-to)1-17
Number of pages17
JournalAquatic Geochemistry
Issue number1
StatePublished - 2000


  • Compressibility
  • Conductivity
  • Density
  • Expansibility
  • Lakes
  • Pvt properties
  • Stability

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology


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