Bryozoans of the Kara Sea: estimation of species diversity and patterns of biogeographic composition

Abstract

Until now, information on the bryozoan fauna of the Kara Sea was as the most unordered in comparison to other Arctic seas of Russia. The information in literature is mainly based on the data collected more than 80 years ago. Collections carried out over the last 30 years made it possible to expand the understanding not only of the species richness of this group, but also to study its spatial variation within the sea. At the moment, the species list of bryozoans in the Kara Sea includes 230 names. Of these, 42 species were recorded for the first time in this area of the Arctic. The fauna richness varies with depth and geographic location of sampling sites. Comparison of the species composition of bryozoans within 6 sectors defined on the basis of differences in environmental parameters indicates the presence of a single faunistic complex. The biogeographic composition of the fauna is characterized by the predominance of the boreal-arctic species (67%) over the arctic (30%); the share of boreal species is only 3%. Comparison of bryozoans from the Kara Sea with faunas from other areas of the Arctic region indicates a closer similarity of its fauna with the fauna of the Barents Sea than with the fauna of bryozoans from the Laptev Sea.