Multivariate analysis performed on surface phytoplankton along Turkish coastal waters of Black Sea revealed presence of distinct aggregates of varying size and species composition. Much more spatial heterogeneity is observed in April than July. Five different small and large sized patchy aggregates were noticed in April 1996 via multivariate analysis (cluster and Multi-Dimensional Scaling, MDS). Based on 60% similarity level 6 different patches are observed in July 1996. Species composition and surface spatial distribution of phytoplankton showed that species differentiation between the shelf and open ocean plankton was apparent. Although, total number of species identified in July 1996 (similar to 119) exceeded much the number of species found in April 1996 (similar to 73), average abundance of cells/l (similar to 9.8x10(5)) found in April ten fold the average cells/l found in July 1996 (9.9x10(4)).