Specific features of vertical distribution and migration of planktonic organisms were studied for estimation of direct pathway of distribution of radionuclides in case they are released in the environment from the sunk nuclear submarine "Komsomolets" (73 degrees 42'N, 13 degrees 15'E, depth 1700 m). The materials were collected by 150-liter bathometers and planktonic nets in July 1994. In addition, planktonic animals were directly counted from deep-sea submarines "Mir". Distribution of the total biomass of plankton was considered and distribution in the water column from the surface to the depth 1700 m was quantitatively estimated for the following species: Calanus finmarchicus, C. hyperboreus, Metridia longa, Euchaeta spp., Sagitta elegans, Themisto abyssorum, and Hymenodora glacialis. The Norway sea hollow is filled by the local Arctic water and this facilitates penetration of many species during seasonal and other migrations down to the demersal layers, i.e., to depths, which are not specific for these organisms in basins with usual water stratification. Mass accumulations of Th. abyssorum have been found in the demersal layer, which is a main component of feeding of commercial plankton-eating fish as well as migrations of this crustacean across the water.