Structure et dynamique de l' algoflore unicellulaire dans les eaux du littoral roumain de la Mer Noire

Abstract

This paper is a multiyear study of the planktonic and benthal unicellular algal flora at the Romanian littoral of the Black Sea and especially between the shore and depths of 30-35 m. The introductory chapters deal with the history of the researches on the algal unicellular flora at the Romanian littoral, presenting the main moments of those studies in the whole Pontic basin as well as the basic materials and working technics used. The paper examines the qualitative structure the whole algal flora by taxonomic, ecologic and phyto-geographic groups as well as the distribution of its specific components at the pelagic and benthal domains. The list of 520 species and varieties of algae found by the author in the sea basin investigated includes 74 new species and varieties for the Romanian littoral, 50 new species for the Romanian flora and 23 new species for the Black Sea. There are also presented data concerning the phytoplankton quantitative structure and dynamics, the total stock of planktonic algae in the area investigated, the influence of the fresh waters on the pontic phytoplankton, large algal bloomings and their causes and their consequences for the ecosystem as well as the necessary steps in order to remedy these consequences. In connection with the microphytobenthos, the author deals with the features of the structure and formation of unicellular associations on the two main categories of sea substrata (mobil sediment and compact substrata), the seasonal dynamics and distribution of the main species and total quantities of algae on mobil sediment at the Romanian littoral, total stock of these algae and their trophic potential, temporal sequence of the microalgal flora on compact substrata, its specific composition and quantity of various types of compact substrata, algal microfouling and its control. The final chapter presents some directions of practical actions in view of equilibrating the coastal ecological systems and of increasing the biological productivity in the final parts of the trophic chains, as suggested by the results of the researches on the planktonic and benthal algal flora achieved by the author.