Plankton stowaways in the Black Sea – Impacts on biodiversity and ecosystem health

The goal of the present paper is to review plankton species focusing on bloom producing exotic stowaways and to discuss the mechanisms of their deleterious effect for the Black Sea ecosystem health. To assess the impact of exotic invasions on the Black Sea pelagic ecosystem, long-term published and unpublished data, collected under national and international projects, as well as the literature were used.

A review of the unpublished data and the published literature revealed an historical trend of exotic species introductions into the Black Sea, with some species transported as early as the mid 18th century and the early 19th century. The number of species, including exotic phyto- and zooplankton blooms, recorded in Black Sea increased dramatically during the late 1980s and 1990s. The list of planktonic aliens represents a high phylogenetic and physiological variability which argues against the proposed “general rules of successful nonindigenous invaders” (Ehrlich, 1989). Thus the elaboration of a “black list of plankton invaders” remains a challenge for the Black Sea scientific community.