An Ice-Bound Planktonic Dinoflagellate Peridiniella catenata (Levander) Balech: Morphology, Ecology and Distribution

On the basis of original plankton and sea-ice samples from the Siberian seas the morphology of the theca in the dinoflagellate Peridiniella catenata has been studied using both light and scanning electron microscopy. All available data on the ecology and geographical distribution of the species have been analysed, its range being presented. It is concluded that P. catenata is one of a few Arctic-boreal dinoflagellates, and cold-water, euryhaline, brackish-water-marine, ice-bound planktonic species. It is the only dinoflagellate hitherto known which is able to develop in abundance in the sea ice. Considering the thecal morphology with emphasis on the sulcal plates, the systematic position of P. catenata, along with the two other species, P. sphaeroidea and P. danica, in the same genus seems to be natural.