Changes in Phyto- and Zooplankton under the Climatic Shifts and Anthropogenic Load (Lake Baikal, Russia)

Abstract

The hydro-chemical data collected today and structural and quantitative parameters of phyto- and zooplankton from Maloe More Strait, Lake Baikal, were analysed. Comparison of current and earlier observations revealed recent alterations in phyto- and zooplankton functions analogous to other areas of Lake Baikal. Major reconstructions in phytoplankton were registered in spring: violation in cycles of annual growth maxima of large-cell Baikalian diatoms and changes in dominant species. Dramatic abundance of rotifers caused the increase by an order of magnitude in pelagic zooplankton numbers in 2019–2020. In 2021, all of these groups were suppressed under intensive diatom vegetation. In the Mukhor bay, such changes were related to a sharp increase of rotifer numbers until 2021. In 2021, we observed decline in plankton abundance, meanwhile the relative proportion of taxonomic groups did not change with dominance of rotifers.