Abstract:
Steppe and semi-desert lakes of Central Asia represent unique and still poorly known
aquatic ecosystems. The paper provides summaries of multi-proxy environmental and biological
investigations of the previously unexplored ground of Sibe lakes in the naturally pristine zone of East
Kazakhstan, and of their contributions to people. Data on the taxonomic composition of zooplankton
and zoobenthos of these freshwater lacustrine basins are presented in terms of the species’ frequency
of occurrence; the abundance of the aquatic biomass and the analyzed water geochemical variables
insofar as they are dependent and correlative. The qualitative and quantitative records display
variability in the biocenosis diversity due to the lakes’ geochemistry and hydrology differences—
some lakes being oligotrophic and others being moderately trophic. In the latter case, the lakes
characterized by an increased macrozoobenthos biomass are favourable for local ichthyofauna. Saprobiological analysis reveals the predominance of β-saprobic species in the zooplankton composition
pointing to slight or moderate pollution of surface waters due to natural biotic substances. This
observation is in agreement with differences in the water quality of solitary lakes. The uneven
distributions of benthic invertebrates (in terms of taxonomy and species populations) in the water
bodies suggest specific hydro-ecological conditions that predetermine the structure of the lakes’
biocenosis. The littoral part of the lakes is characterized by the highest abundance of zooplankton
and benthic fauna. The Sibe lakes are an example of an autonomous functioning of the lacustrine
basins in the upland arid steppe zone, which is characterized by pronounced climate “continentality”
and a high level of the sub-aquatic flora and fauna endemism. The present results are relevant to
the understanding of the ecosystems’ dynamics and the modern anthropogenic impacts upon the
pristine parkland-steppe landscapes of Central Asia, with implications for regional nature protection
and sustainable eco-recreation.
