Comparison of the phytoplankton assemblages of the south-eastern Barents Sea and south-western Kara Sea: Phytogeographical status of the regions

A comparison of the taxonomic composition of the diatom and dinoflagellate assemblages has been carried out for the south-eastern Parents Sea (Pechora Sea) and the south-western Kara Sea. All available literature and original data have been used in making the floristic lists which have been corrected for synonymy. The number of microphytoplankton species found in the south-western Kara Sea is somewhat higher than in the south-eastern Parents Sea (221 vs. 184 species respectively). The difference is most significant for the dinoflagellates (88 vs. 67 species). Diatoms formed a major part of the communities, accounting for 60% of the taxonomic composition in the Kara Sea, and 63% in the Parents Sea. In both regions, about 60% of the diatom assemblages are represented by centric diatoms, most of them being typical planktonic chain-forming species. A high similarity between the two areas was characteristic for most phytogeographical and ecological groups of the pelagic microalgae, and therefore we suggest that the plankton communities form a floristic entity with the status of a phytogeographical province. We name it the Novaya Zemlya Phytogeographical Province. The major reason for considering these two areas a biogeographical unit, is the similarity in the microphytoplankton assemblages and the stable water exchange which exists between the areas.