The diatom distribution in the surface sediments of the Eastern Arctic seas of Russia

The distribution features of diatoms in the surface sediments of the Laptev, East Siberian, and Chukchi seas were studied. The sediment diatom content varied widely, being lowest in the East Siberian Sea and highest in the Chukchi Sea. Cluster analysis revealed several diatom assemblages in the surface sediments of the studied region; their distribution depended on the hydrological conditions. A benthic Amphora libyca assemblage, a freshwater Aulacoseira subarctica one, and a brackish-water Thalassiosira hyperborea assemblage were identified in the Laptev Sea. A cold-water Th. antarctica assemblage was distinguished in the eastern part of the East Siberian Sea and in the northern Chukchi Sea; a highly productive Chaetoceros assemblage was noted in the Herald Canyon area; a sublittoral Odontella aurita assemblage occurred in sandy sediments of the Herald Shoal; a Paralia sulcata assemblage, which is an indicator of low salinity waters, was found in the eastern Chukchi Sea near Alaska; and ”sea-ice” Th. nordenskioeldii and Fragillariopsis oceanica assemblages occurred in the southern Chukchi Sea.