Recent Benthic Foraminiferal Assemblages in the Western Part of the East Siberian Sea

Benthic foraminiferal assemblages were studied in twenty surface sediment samples collected in the western part of the East Siberian Sea in the framework of the expedition of the R/V Ivan Kireev in 2004. Rose Bengal treatment made it possible to separate “living” and dead individuals. Taxonomic analyses reveal that “living” calcareous foraminifers dominate in the study region with the exception of the New Siberian Islands area and area to the northeast from the Indigirka River mouth where agglutinated tests constitute up to a half of the assemblage. Little amount of dead individuals points to a rapid dissolution of calcareous tests immediately after death of the organism. Taxonomic composition of the studied assemblages is similar to river-proximal benthic foraminiferal assemblage previously determined for the Kara Sea. In the East Siberian Sea, Elphidium clavatum , Elphidiella groenlandica , Haynesina orbiculare , E. incertum and Lagenammina atlantica are the most common species. Gordiospira arctica , Buccella frigida , E. bartletti , Reophax curtus , R. scorpiurus and polymorphinids are less abundant taxa. As a result of the statistical analysis, four areas with specific BF assemblages have been distinguished: the area of the Indigirka River mouth, the zone affected by the Siberian Coastal Current, the area located to the north of the Siberian Coastal Current and zone situated close to the New Siberian Island archipelago together with an area located to the northeast from the mouth of the Indigirka River. Such a distribution of benthic foraminiferal assemblages in the study region seems to be related to the distance of the river discharge area, type of sediments and fresh organic matter content.