The Spatial Distribution of Plankton Picocyanobacteria on the Shelf of the Kara, Laptev, and East Siberian Seas.

The spatial distribution of picocyanobacteria at the arctic longitude section passing through the shelf of the Kara, Laptev, and East Siberian seas from 58° to 168° E was studied. The average abundance of picocyanobacteria was 0.48 ± 1.2 × 10⁹ cells/m³ in the Kara Sea, 0.16 ± 0.24 × 10⁹ cells/m³ in the Laptev Sea, and 0.25 ± 0.43 × 10⁹ cells/m³ in the East Siberian Sea. The fluctuations of picocyanobacterial abundance were determined by their presence in allochthonous sources: river flow and transformed North Atlantic waters. The highest abundance was observed in the areas of the runoff influence of the Ob, Khatanga, Indigirka, and Kolyma Siberian rivers: 0.5 × 10⁹, 0.2 × 10⁹, 0.4 × 10⁹, and 1.6 × 10⁹ cells/m³, respectively. The average contribution of picocyanobacteria to the total abundance and biomass of picophytoplankton in the western part of the Kara Sea was 37 and 36%, respectively. In other regions, the average contribution of picocyanobacteria to the total abundance and biomass of phototrophic picoplankton did not exceed 7 and 6%, respectively. A highly reliable (p 0.01) positive correlation between the abundance and biomass of picocyanobacteria and the water temperature (p = 0.003) was revealed in the entire dataset obtained. [ABSTRACT FROM AUTHOR]