Assessing the Key Environmental Factors in the Formation of Phytoplankton Spatial Structure in Large Subarctic Rivers (East Siberia)

Data of 2000–2011 on phytoplankton of 12 large subarctic rivers, their hydrochemical, hydrological, and morphometric parameters and the climatic characteristics of their drainage basins have been analyzed with the use of step-wise discriminant analysis and clusterization of observations to establish that the formation of phytoplankton spatial structure in rivers in the northeastern Siberia is governed by climate rather than water physicochemical properties. Among the characteristics of phytoplankton development, its floristic structure shows the closest correlation with abiotic factors. An important environmental factor is the duration of growing season .