Influence of Environmental Factors on the Structure of Plankton Communities in Saline Lakes at Different Water-Fill Phases

Abstract

The work is based on the results of long-term studies on phytoplankton and zooplankton in sodasaline lakes of the Uldz Gol-Torey basin (southeastern Trans-Baikal region). The unstable level regime of steppe lakes, due to climate fluctuations, leads to changes in the morphometric and hydrochemical regime of the lakes, and, as a consequence, to transformation of the plankton community. The goal of this work is to identify and analyze environmental factors that determine the structure of planktonic biocenoses in mineral lakes at different water-fill phases. According to statistical analysis of auxiliary models based on the redundancy analysis (RDA), the significance factors were mineralization and pH in the transgressive water-fill phase and pH in the regressive phase. Schematic drawings of interrelationships within the plankton community are constructed on the basis of the correlation matrix. There were nine interrelated components in the plankton natural associations in the high-water period and only five components at a low-water level. Chlo-rophyta was found to be a basic constructive element of the plankton community regardless of the water level. Euglenophyta, Bacillariophyta, and Cladocera were the second most significant elements in the structural organization during the full-water period and Charophyta, Dinophyta, Rotifera, and Copepoda were during the water-short period.