D. Petrova, G. Kostadinova, D. Gerdzhikov
Abstract. The purpose of this article was to study and make an ecological assessment of the phytoplankton community in the Bulgarian Black Sea coastal waters for the period 2008 – 2010. Taxonomic distribution in the phytoplankton community is traced and analyzed on the basis of 389 quantitative and qualitative seawater samples. Dominant and subdominant phytoplankton species, qualitative and quantitative monthly and seasonal dynamics of the main groups in phytoplankton have been identified as well as their importance for the ecological status of the Black Sea ecosystem. The obtained results for phytoplankton demonstrated a comparative reduction of the trophic degree of the Bulgarian coastal waters, dominating natural factors of the environment over the anthropogenic ones and the present status of “good” and “very good” of the researched coastal area, according to the explored parameters. The phytoplankton annual development is accordingly with the climatic conditions. Also three seasonal phytoplankton successions were defined throughout the year.