Stratigraphy And Paleolithic Landscapes of the Beganchik Site at the Kama-Volga Confluence

The Beganchik locality is a stratigraphic sequence of loessic deposits, pedogenic horizons and Paleolithic occupations located at the Kama-Volga confluence. The sequence is exposed on a bluff formed on the west side of an erosional remnant between the Kuybyshev Reservoir and the former channel of the Aktay River. Although the site is known for its Terminal Paleolithic-Mesolithic occupations of the Pleistocene-Holocene transition, evidence of older occupations and remains of fauna has been identified. Our research team identified evidence of human presence associated with a pedogenic horizon of MIS 3 age. Two AMS radiocarbon ages from a hearth produced ages around 47 000 years BP. Pollen and phytoliths from two soils horizons, including the one associated with the hearths indicate a steppe environment coincident with the formation of correlative soils elsewhere in the Russian Plain.

Changes in biological indicators of the silver bream Blicca bjoerkna at the upper part of the Volga stretch of the Kuybyshev reservoir in connection with the anthropogenic impact

In recent years, the silver bream of the upper part of the Volga stretch of the Kuibyshev reservoir maintained a tendency to reduce the average size and weight indicators. Given the good availability of food and the fact that in the area under consideration, commercial fishing of this species has not been carried out in recent years, it can be assumed that changes in biological indicators are caused by a significant impact of anthropogenic impact in the form of individual and poaching fishing. It is necessary to strengthen control measures for such types of fishing.

Spatial-temporal Transformation of the Volga Reservoirs’ Soil Complex Communication 6. The Kuybyshev Reservoir Bottom Sediments and their Mapping with the Use of Geo/information Techniques

The article presents the geo/informational analysis of the spatial/temporal transformation of the Kuybyshev Reservoir soil complex structure and qualitative composition according to the materials of hydrological surveys of 1961, 1983, 2001–2002 and 2015–2017. As a result of the raster images vectorization we obtained three topical geo/information layers, every one of them contained the data sufficient for mapping the appropriate period of the researches. Analysis of the fourth layer in the area of the model Volga-Kama Expansion (F = 1011 km2) characterized by a complicated crest-shallow bottom relief, diverse hydrodynamic processes caused by water input via the Volga and the Kama and a wide spectrum of the windwave activities has shown insignificant changes in the bed structure after 2002. In 2015–2017 analysis of the bottom sediments types’ distribution at 45 control stations has reaffirmed the stability in all 10 orographic stretches (reaches). Increase of the stations’ number will make more complicated the bottom sediments distribution mosaic and will not significantly change their spatial/temporal transformation found during the first years of the reservoir functioning. We have found that at the current stage the reservoir soil complex is represented by coarsegrained deposits (44%), fine-grained sediments (42%), diffused rocks (13%) and waterlogged soils 91%) located near the floodplain islands of the Kazan and Chistopol regions of variable backwater. The organic matter and biogenic elements content is at the level typical for the plain reservoirs’ bottom sediments. The Kuybyshev Reservoir level of heavy metals pollution in the Volga cascade system has been estimated as low.

The Dissolved Non-organic Phosphorous Content in the Water of the Kuybyshev Reservoir

The intra-year variability of dissolved non-organic phosphorous content under the Kuybyshev Reservoir anthropogenic euthrophication conditions has been investigated on the basis of many-year observations. The observations were conducted on the Volga River during the 2000–2015 period in the vicinity of the Zhiguly Dam. The Kutbyshev Reservoir is located upstream from the dam and the Saratov Reservoir is located downstream. It has been stated that the phosphorous content in water has a pronounced seasonal variation while the amplitude of within-year fluctuations of the phosphorous content depends on the intensity of algae mass growth process. In comparison with 1950s the amplitude of within-year fluctuations of the phosphorous concentration has increased significantly and currently it is 0.001–0.0149 mgR/dm3, this confirms the fact of the Kuybyshev Reservoir anthropogenic euthriphication process intensification. It has been found that the seasonal changes in the phosphorous and chlorophyll «a» concentrations are in anti-phase. As soon as the phosphorous concentration becomes less than 0.010 mgR/dm3, algae growth stops. Thus, phosphorous dissolve in water is a critical factor of the algae growth in the reservoir water. Decrease of the phosphorous concentration in the Volga water will enable to mitigate intensity and duration of the water blooming period in the Kuybyshev Reservoir but for this end it is necessary to restrain the non-organic phosphorous input to the reservoir from point and diffuse pollution sources.