Different types of mesoscale eddy dynamics are considered in the paper from the viewpoint of their effect on the plankton (mainly phytoplankton) amount and its taxonomic structure. The eddy structures of all types, including cyclonic, anticyclonic, water-body anticyclonic and frontal ones, as well as the dipole structures, actively affect plankton. Theoretical schemes of the influencing mechanisms, which are illustrated by the examples of such an impact on the plankton in the Black Sea, are examined. The analyzed responses of the marine plankton ecosystems to the eddy dynamics and the scientific literature review unambiguously testify the important role of these processes in formation of biological productivity in the seas and oceans. Thus, a cyclonic eddy forms the isopycn rise (a domelike bend) in its core both in the thermocline and in the pycno-halocline that elevates nitrocline; it promotes bioproductivity increase. Whereas in the anticyclonic eddy core, the thermocline and pycno-halocline lowering (deflection) takes place; it negatively affects bioproductivity. At that, the isopycn rise occurs at the eddy periphery that, on the contrary, contributes to increase in primary production. In contrast to a conventional anticyclone, a lens-like eddy forms the water rise exceeding the maximum velocity horizon, in other words, in its upper part it often acts like a cyclone. Thus, in any gyre there are the areas where the thermocline rises to the surface and, therefore, the prerequisites for the bioproductivity increase are formed. Strong winds not only enhance the affect of the eddies on biota, but can completely change the nature of this impact. When exposed to wind, the rate of entry of the biogenic elements to the photic layer in the cyclones can decrease, whereas in the lens-like anticyclones it can increase. The important point is that the long-living eddies change the influencing mech-anisms depending on the stage of their evolution. At last, the eddy structures often promote changing in the dominant phytoplankton species that can significantly alter the flow of organic matter to the bottom and affect the global carbon cycle.