Coexistence of Nonnative and Black Sea Phytoplankton Species: Discussion of Invasion Hypotheses

In spring and early summer 2005, a new Mediterranean diatom species, Chaetoceros trondsenii, was marked in phytoplankton of the northeastern Black Sea. The parameters of the created phytoplankton species dynamics model were determined in experiments with nitrogen and phosphorus supply. Computa tional experiments with the model gave the following results: for Chaetoceros trondsenii establishment in an ecosystem, an elevated stability of the water column (water rate exchange in the upper mixed layer should be lower than 0.1 day–1), a relatively high initial number of this species, and low values of nitrogen and phospho rus concentration at the boundary of the seasonal thermocline are necessary. The hypothesis of the introduc tion of the species into the Black Sea by the raised intrusion of Mediterranean water in winter is more pref erable than the hypothesis of releases of the species with ballast water. DOI: 10.1134/S2075111711040102