While in the early neogene, tectonic and to a lesser extent climatic factors impacted on the sea level, at the present stage climatic, man-made and anthropogenic factors are at the forefront. As a result of an increase in the level of the Caspian Sea by more than 2.4 m, 35-40 thousand square meters km of territory was flooded, during the flooding and flooding of the coastal territory for the period 1978-1995 led to a change in natural, socio-economic and medico-ecological conditions. The consequences of rising sea levels led to the resettlement of about 100 thousand people living in the coastal flooded zone of the Northern Caspian Sea and many industrial facilities.

Aim. The purpose of the research was to study the state of hydrobionts in the Tyub‐Karagan Bay structure by season for a comparative analysis of their state with previous studies by the authors.Material and Methods. The conditions of hydrobionts (phyto, zoo‐plankton and macrozoobenthos) of the Tyub‐Karagan Bay structure have been studied for three seasons. Studies were carried out by traditional methodology.Results. The species composition of phytoplankton communities in spring was found to be less constant than in autumn; this is associated with heterogeneity in external conditions at the beginning of the growing season. The seasonal dynamics of zooplankton conformed to certain patterns. As a rule, from the beginning to the end of the growing season there was an enrichment of species composition and an increase in the quantitative indicators of zooplankton communities. The highest biomass was formed by bottom cenoses, where large mollusks play a leading role.Conclusion. During the 2018 research period, species richness and species diversity of phytoplankton were at a high level. Representatives of two categories were observed most often. Blue‐green dominated in number, while diatoms formed the basis of biomass. Species richness and species diversity of zooplankton was at a low or moderate level and most often constant. The seasonal dynamics of macrozoobenthos had common and specific features, depending on the research station location. Disproportionate changes in the quantitative indicators of bentonites are associated with a decrease in the average weight of individuals by autumn. This happened both through the strengthening of the role of small species and by an increase in the proportion of younger age stages in populations of bottom invertebrates.

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Тенденции развития науки и образования оттенок.Увеличение продолжительности прокалки при 350°C свыше 3 час не приводит к существенному уменьшению содержания влаги.

Prior to the start of experimental oil production in the Kashagan field (northern part of the Caspian Sea), n-alkanes and carboxylic acids contained in samples obtained from bottom sediments in the area of artificial island “D” were investigated by gas chromatography–mass spectrometry. Concentrations of 10 n-alkanes (composed of C10-C13, C15-C20) and 11 carboxylic acids (composed of C6-C12, C14-C16) were identified and measured. Concentrations of individual alkanes and carboxylic acids in bottom sediments of the various samples varied between 0.001 ÷ 0.88 μg/g and 0.001 ÷ 1.94 μg/g, respectively. Mass spectra, in particular the M+ molecular ion peak and the most intense peaks of fragment ions, are given. The present study illustrates the stability of molecular ions to electronic ionisation and the main fragment ions to the total ion current and shows that the initial fragmentation of alkanes implies radical cleavage of C2H5 rather than CH3. All aliphatic monocarboxylic acids studied were characterised by McLafferty rearrangement leading to the formation of F4 cation-radical with m/z 60 and F3 cation-radical with m/z 88 in the case of ethylhexanoic acid. The formation of oxonium ions presents another important aspect of acid fragmentation. Using mass numbers of oxonium ions and rearrangement ions allows determination of the substitution character in α- and β- C atoms. The essence of our approach is to estimate the infiltration of hydrocarbon fluids from the enclosing formation into sea water, comprising an analysis of derivatives of organic compounds in bottom sediments. Thus, concentrations of derived organic molecules can serve as a basis for estimates of the depth at which hydrocarbon fluids leak, i.e., to serve as an auxiliary technique in the search for hydrocarbon deposits and to repair well leaks.