Diatom assemblages in 62 surface sediment samples from the outer Ob and Yenisei estuaries and the adjacent inner Kara Sea shelf were examined in relation to environmental conditions. Concentrations of diatoms reflect the biological productivity of surface waters along with specific water mass processes of diatom valve deposition in the zone of intermixing of riverine and marine waters. An inverse relationship between total concentration of diatom valves in sediments and surface water salinity is found. Extremely high abundances of diatom valves (up to 82.4 million valves/g sediment) are observed in the outer Ob and Yenisei estuaries (salinity 10-20%) correspond to the mean interannual location of the winter polynya corroborating previously obtained results from the Laptev Sea.

Supplement to: Polyakova, Ye I (2003): Diatom assemblages in surface sediments of the Kara Sea (Siberian Arctic) and their relationship to oceanological conditions. In: Stein, R; Fahl, K; Fütterer, D K; Galimov, E M & Stepanets, O V (eds.), Siberian River Run-off in the Kara Sea: Characterisation, Quantification, Variability, and Environmental Significance, 488 pp. Proceedings in Marine Sciences, Elsevier, Amsterdam, 6, 375-399