The paper presents the data on the long-term studies of phytoplankton and microphytobenthos of the Chernaya River (Vyborg region), including the hydrochemical water composition and particle-size distribution in soil. Species richness of phytoplankton is higher than that of microphytaobenthos. In both communities, diatoms prevail; the dominant species is Aulacoseira subarctica (O. Müller) E.Y. Haworth. The seasonal dynamics of phytoplankton abundance is typical for water bodies in northwestern Russia. © 2025 Elsevier B.V., All rights reserved.