p. 181 - 198 VARIATION OF CERTAIN ENVIRONMENTAL FACTORS IN THE ZONE INHABITED BY MARINE BENTHIC ALGAE OF THE ROMANIAN SHORE OF THE BLACK SEA Florian Vasiliu, Georgeta State and Ion Bucse Romanian Marine Research Institute Constantza Abstract The paper presents the results of the observations on certain environment factors, during 1971 in a zone with macrophytic associations on the Romanian Black Sea shore. The following measurement data are included: light, suspended matter, water temperature, salinity, organic matter, dissolved oxigen, phosphates, and biochemical oxigen demand. All these measurements and observations, correlated with certain data on the biology of some marine benthic algae, particulary of the Cystoseira sp., showed that during 1971, particulary favourable conditions were prevalent on the Romanian sea shore for the increase of the marine benthic algae stock.