THE ECOLOGICAL-GEOCHEMICAL CONDITION OF MEADOW-PASTURE ECOSYSTEMS OF THE VOLGA-AKHTUBA FLOODPLAIN

Abstract. Aim. The central aim of this article is the study of ecological-geochemical state of meadow-pasture ecosystems of the Volga-Akhtuba floodplain taking into account the changing ecological conditions of the region. Methods. Determination of total content of trace elements in soil and plant samples was performed by atomic absorption spectroscopy. Results. Flooding is the main factor in the formation of floodplain soils and meadow vegetation. The duration and nature of floods depend on natural and anthropogenic factors. Changes in chemical trace element content in meadow – pasture ecosystems of the Volga-Akhtuba floodplain are largely dependent on seasonal flooding. The analysis of changes in heavy metal concentrations before and after flooding in floodplain soils and vegetation showed that after flooding observed decrease of heavy metals content and the percentage reduction (%) of total contamination factor. Flood waters dissolve minerals in the soil and contribute to their migration. Conclusions. The processes of formation of chemical composition of ecosystems are determined by the properties of individual elements. Trace elements accumulate in different amounts. The composition of the soil is directly influenced by the processes of biological accumulation, which leads to the accumulation of cobalt (Co), chromium (Cr) in the surface horizons. The vegetation of the floodplain mainly comprises iron (Fe) and chromium (Cr). The concentration of heavy metals in soil and vegetation of the Volga-Akhtuba floodplain has the following descending series: Fe > Mn > Zn > Ni > Cr > Cu > Pb > Co > Cd.

Volgo-Akhtuba floodplain, meadow pasture ecosystems, microelement composition, soil, vegetation, heavy metals

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