p. 51 - 61 OBSERVATIONS SUR L'EVOLUTION DES PRINCIPAUX PARAMETRES PHYSICO-CHIMIQUES DE L'EAU MARINE DE LA ZONE CONSTANTA Adriana Cociasu, Lucia Popa Institute Roumain de Recherches Marines Constanta Abstract Based on daily-performed observations at Constanta during 1959-1979, the paper follows the general tendency of salinity, oxygen and nutrient evolution in the shallow waters along the Romanian coast of the Black Sea. At the same time, important quantitative changes are identified in the annual cycle and multiannual dynamics, as generated by the variability of the hydrological and hydrobiological agents characteristic of the studied area.