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1.
Water Resources - The analysis of data on the space and time variations of the concentrations and element composition of organic matter dissolved in Caspian Sea water over 2010–2015 showed... 相似文献
2.
Mean concentrations of microelements Mn, Rb, Sr, Mo, Ba, Fe, Cu, and U in the Caspian Sea evaluated based on the results of water sampling in 1995 are given. The obtained values are checked against the requirements to the characteristics of water bodies used for fishery. 相似文献
3.
Current Variations in the Wind Speed Vector and the Rate of Evaporation from the Caspian Sea Surface
Regularities in the rearrangement of the surface atmospheric circulation in the Caspian Sea region are studied. It is found that during the current rise in the Caspian Sea level, a statistically significant decrease in the wind speed modulus occurred (mainly in autumn and winter winds of zonal directions). This caused a decrease in the rate of evaporation in the region. The results of this study testify to a need for developing a deterministic model of current variations in the Caspian Sea water regime at varying global and regional climate. 相似文献
4.
M. V. Isupova 《Water Resources》2008,35(6):615-634
Long-term water level variations in the Volga mouth area and the effect exerted on them by the river’s flow and the Caspian Sea’s level variations are considered. Quantitative relationships were identified between the mean annual water levels at different gages in the mouth and the sea level. A backwater component was isolated in the long-term variations in water level in the Volga mouth area. Relationships between the daily water levels in the mouth and the Caspian Sea’s level at fixed water flow in the delta apex are presented. The magnitude and the propagation distance of backwater from the sea into the delta are specified. The responses of the mouth areas of rivers emptying into the Caspian Sea to sea level variations in the past century are compared. 相似文献
5.
A new thermophysical mechanism of the Caspian Sea level variations is proposed. The mechanism incorporates the effect exerted on the dynamics of the water budget of the Caspian Sea by the nonlinear dependence of the evaporation rate on the moistening of the basin. 相似文献
6.
A. A. Svitoch 《Water Resources》2008,35(2):165-170
The Late Pleistocene history of the Caspian and Black seas is considered. It is suggested that the New-Euxinian basin was to a great degree due to the penetration of the Caspian water through the Manych depression into the Black Sea during the Caspian-Early Khvalynian transgression. 相似文献
7.
The available observational data on the pollution of tributaries and areas of the Caspian Sea by petroleum hydrocarbons and
products are examined. The possible petroleum input from sources in the sea is assessed using up-to-date data of satellite
observations of sea surface pollution by oil films. The hydroecological CNPSi-model is applied to studying water pollution
processes by petroleum hydrocarbons in ten areas chosen in the Caspian Sea and the subsequent biodegradation of those pollutants.
The model calculations of the within-year dynamics of petroleum hydrocarbon concentrations use mean annual observational data
on within-year variations in water mediium characteristics (water temperature, light intensity, and transparency), as well
as the morphometric parameters of sea areas (the area, mean depth, and water volumes). The characteristics of water exchange
between the areas were evaluated using a hydrodynamic model. The model calculations were used to characterize the within-year
variations in petroleum hydrocarbon concentrations, the biomasses of petroleum-oxidizing bacteria, the characteristics of
their oxidation activity and bioproduction, and the internal fluxes of petroleum hydrocarbons (their input from various sources,
horizontal and vertical transport, and biotransformation) in different sea areas. Calculation results were used to compile
annual balances for the processes of input and consumption of petroleum hydrocarbons in the chosen and aggregated sea areas. 相似文献
8.
The concentrations and the elemental and biochemical composition of dissolved and particulate organic matter (OM) characteristic of southern and Arctic seas are presented. The rate of OM transformation in the production–decomposition cycle and that of the phosphate cycle are estimated from the activity of the redox enzymes of the electron-transport system and that of phosphatase. Carbohydrates and protein are shown to be the main biochemical components in the water of all the seas under study in dissolved and particulate OM, respectively. The contribution of carbohydrates to particulate OM under the conditions of intense primary production is demonstrated to be comparable to that of protein. High concentrations of lipids are shown to be characteristic of the coastal ecosystems in the middle Caspian Sea and northwestern shelf of the Black Sea because of severe pollution in these areas. It is noted that at higher trophic levels, the ecosystem of the Caspian Sea intensely assimilates allochthonous OM, and that the Black Sea ecosystem transfers considerable amounts of OM to the hydrogen sulfide zone. 相似文献
9.
A. P. Demin 《Water Resources》2007,34(3):237-253
Indices characterizing the withdrawal of water resources in the basins of rivers flowing into the Caspian Sea and the use of these resources in different economic sectors in 1970–2003 are analyzed. The dynamics of disposal of wastewaters and collector-drainage waters is discussed. Tendencies in changes in the volumes of consumptive water use in the basins of individual rivers and the Caspian Sea as a whole are identified. 相似文献
10.
Normal annual data are used to evaluate the within-year variations in the concentrations of biogenic substances (organic and mineral components of N and P, dissolved organic carbon, inorganic Si) in the major tributaries of the Caspian Sea. Variations in the concentrations of biogenic substances are analyzed, the relationships between their mass concentrations in individual months are evaluated, and correlation between the organic and mineral components of N and P and their aggregated fractions are established. The obtained high-significance correlation between the concentrations of N and P components suggests that the rates of biochemical processes of biogenic substance transformation taking place in the water of tributaries are commensurable. 相似文献
11.
The distribution of some microelements (Sr, Si, Ba, Mo, Rb, and Mn) in the surface and deep-sea waters in various parts of the Caspian Sea is considered in comparison with the distribution of salt-forming macroelements. The observed mean concentrations of microelements and their variations over the sea area and with depth indicate to the presence of additional, other than Volga runoff, sources supplying Sr, Ba, U, Rb, and Mn to the Caspian Sea. 相似文献
12.
The tritium content of the surface water on the south shore of the Caspian Sea was determined in samples taken in two- to three-month intervals for the period of time from 1960 to 1970. Tritium concentrations following the massive H-bomb testing in 1962 and 1963 were particularly high in this water, much higher than in the surface waters of the open oceans. The data are interesting in connection with the tritium inventories on the continents and with the persistence of inert chemical pollutants in the surface layers of water masses. 相似文献
13.
《Marine pollution bulletin》2014,85(1-2):391-400
A comparative study of 23 PAH congeners in sediment of the Caspian Sea coast and Anzali Wetland was conducted in 2010. Surface sediment was analyzed using chromatography and mass spectrometry. Total PAH concentrations ranged between 212 and 9009 ng g−1 dw. Spatial distribution maps revealed that PAH levels were higher in the coastal areas of the Caspian Sea where oil related activities have been common since 1800’s. Diagnostic ratios analysis indicated that PAHs largely originated from petrogenic processes. PAH toxicity level was assessed using sediment quality guidelines and toxic equivalent concentrations to determine toxic effects on marine organism. Based on these investigations, in our study areas, the probability of toxicity for benthic organisms is “low to medium”. The toxic equivalent concentrations of carcinogenic PAHs varied between 11 and 231 ng TEQ/g; higher total toxic equivalent concentrations values were found in the coastal areas of the Caspian Sea. 相似文献
14.
The results of studying the hydrological regime of the Caspian Sea and its basin climate in observation period 1945–2010 are generalized. The results of analysis of the regime of precipitation, air temperature in the Caspian Sea basin and its level, as well as Volga runoff in periods of Caspian Sea level rise and drop are given. The conformity in variations of the trends in Caspian Sea level its basin climate is demonstrated, and the direction of further studies is substantiated. 相似文献
15.
I. A. Nemirovskaya 《Water Resources》2016,43(1):111-120
The presented results have been obtained in a study of the concentrations and composition of aliphatic and polycyclic hydrocarbons in bottom sediments of Volga delta branches and in its shallow zone (2009–2010), as well as the Caspian Sea proper (2010–2013). Oil hydrocarbon pollution has been found to manifest itself mostly in Volga delta branches, which, despite the low concentrations (up to 54.5 μg/g), showed higher hydrocarbons share in Corg (up to 33.8%), while the composition of alkanes suggested their oil genesis. The geochemical barrier the Volga–the Caspian Sea prevents anthropogenic hydrocarbons from entering the open parts of the Caspian. Bottom sediments in the shallow zone of the Northern Caspian, represented by coarse-grained material, are now polluted by oil hydrocarbons to a lesser extent compared with other areas. The highest concentrations of aliphatic hydrocarbons (up to 178 μg/g) were recorded in the deepsea bottom sediments of Derbent Depression and in depressions of the Middle and Southern Caspian. These areas show a higher concentration of Corg (up to 9.884%) and a low concentration of hydrocarbons in Corg (up to 0.16%), while odd high-molecular homologues (n-C25–C31) dominate in the composition of alkanes. 相似文献
16.
Present changes in the regime and structure of mouths of rivers, which empty into the Caspian Sea, are discussed. The similarities and differences of these processes at the mouths of different rivers of the Caspian Region were revealed. Assessment was made of the impact of changes in river water runoff and sediment load and in the Caspian Sea level as well as the nearshore zone relief and local hydraulic engineering activities on the processes under study. Anomalous features of the processes occurring at the mouths of the Volga and Terek rivers were revealed and explained. Hydrological and morphological processes typical of the present mouths of the rivers of Ural, Sulak, and Kura were revealed; these processes could be accepted as universal and possible analogs in assessing the expected changes at the mouths of other rivers in Russia and the world in the XXI century. 相似文献
17.
The results of monitoring studies of organic matter content of bottom sediment, water, and surface microlayer carried out
during expeditions of 2000–2004 in northwestern Caspian Sea are presented. 相似文献
18.
Nonlinear dynamics of level variations in the Caspian Sea 总被引：2，自引：0，他引：2
Caspian Sea level variations, which have several equilibrium states, are studied by the methods of the theory of nonlinear dynamic systems. Normal monthly values of sea level according to data collected at Makhachkala gauge from 1900 to 2000 are considered. The diagnostic characteristics of dynamic chaos are used to show that sea level variations have some properties of series with chaotic behavior. A model of level variations in the Caspian Sea, comprising a system of water balance equations for the sea basin, the dynamics of river runoff, and water balance of the sea itself, is proposed. Equation of a nonlinear oscillator is derived and shown to have solutions with chaotic regimes at some combinations of parameters. 相似文献
19.
Water Resources - The runoff of glacial melt water into the river system of the Volga and farther into the Caspian Sea is evaluated for the epoch of the last glaciation. Melt water entered the... 相似文献
20.
Aliphatic and aromatic hydrocarbons in coastal Caspian Sea sediments 总被引：17，自引：0，他引：17
Tolosa I de Mora S Sheikholeslami MR Villeneuve JP Bartocci J Cattini C 《Marine pollution bulletin》2004,48(1-2):44-60
This investigation represents the first extensive study of the spatial distribution and sources of aliphatic (n-alkanes and unresolved complex mixture of fossil hydrocarbons) and polycyclic aromatic hydrocarbons (PAHs) in coastal sediments from the Caspian Sea. PAH concentrations, n-alkanes and biomarker profiles all suggested that there was limited petrogenic contamination in the shallow North Caspian Sea sediments, which are coarse with a low total organic carbon content. In contrast, moderate to high petrogenic contamination was found in the South Caspian Sea, in particular in the offshore oil fields near Baku, Azerbaijan. Contaminant patterns indicated that the PAHs were mainly from fossil sources, with higher contributions of pyrolytic only near industrialized and urban areas. A high contribution of perylene, a geochemically derived PAH, to the total PAHs was found in the west and south at sites influenced by the Kura, Safid Rud, Terek, Sulak and Samur Rivers. 相似文献