p. 91 - 102 DONNEES SUR L'ECOLOGIE ET LA PRODUCTIVITE DES ESPECES DE CYSTOSEIRA DE LA MER NOIRE Florian Vasiliu Institute Roumain de Recherches Marines Constanta Abstract The present paper describes some pecularities that have concern with Cystoseira genera along the Romanian sea shore. Ecological conditions of the areas populated by these seaweeds, the pronunced trend of them quantitative diminishing, as well as datum on Cystoseira barbata productivity are presented. An original procedure for primary productivity determination is decribed, too.