Synthese des observations réalisees par l'I.S.T.P.M. sur les eaux et le plancton de l'etang the Thau de 1974 a 1980.

The results of a great number of measurements and water analyses realized by I.S.T.P.M. in the lagoon of Thau between 1974 and 1980, have led to the establishment of the mean variation of some hydrological parameters during the year. Monthly mean values of temperature, salinity, pH, dissolved oxygen, nutritive salts and abundance of plankton, were studied as well as possible relations between these factors. The observed differences between the surface and the bottom are related as well as gradiation between the entrance and the end of the lagoon.