scholarly journals ANALYSIS OF PRODUCTIVITY OF SPONGE (SPONGILLIDAE) GROWING IN WATER BODIES OF THE VOLGA RIVER DURING REGRESSION OF THE CASPIAN SEA

2019 ◽  
pp. 57-65
Author(s):  
Nikolay Aleksandrovich Franov ◽  
Alexander Nickolaevich Nevalennyy ◽  
Arkadii Fedorovich Sokolsky
Keyword(s):  
Caspian Sea ◽  
Water Bodies ◽  
Raw Material ◽  
Small Rivers ◽  
The Caspian Sea ◽  
Volga River ◽  
Livestock Breeding ◽  
Central Russia ◽  
Microscopic Studies ◽  
Effective Development

The article describes the habitat, systematics and species of freshwater sponge ( Badiaga spongia fluviatilis ) inhabiting water bodies of Russia. There have been characterized the hydrological features of water bodies - sponges’ habitats, and their ecological function has been characterized. In freshwater bodies of the central Russia there occur two most common and numerous types of sponges - lake badiaga ( Spongilla lacustris ) and river badiaga ( Ephydatia fluviatilis ) presenting a valuable raw material for the pharmaceutical and cosmetic industry. The attention is focused on the fact that sponge colonies can reach the commercial volumes only in the floodplain waters and the delta of the Volga River. Retrospective data on volumes of sponge fishery in the Astrakhan region suggest the reason for decreasing sponge productivity and volume of the sponge industry: a lack of reclamation works in small rivers in the Volga delta. There has been given a comparative analysis of the data on microscopic studies of sponge structure caught on experimental zones in the water bodies of the Astrakhan region and the information found in the scientific literature. Characteristics of soils where significant sponge plantations were found are analyzed. It has been stated that in the watercourses of the Astrakhan region there prevail species of lake sponge ( Spongilla lacustris ), whose biomass should increase tenfold taking into account the cyclicity of the regression processes of the Caspian Sea, carrying out complex ameliorative works on the waterways of the Volga and development of agriculture and livestock breeding. It has been recommended to prepare a scientific and production base for the rational and effective development of the potential of this natural resource for pharmaceutical and cosmetic purposes.

THE NUMBER AND QUALITATIVE CHARACTERISTICS OF FRY FISH IN SHALLOW COASTAL WATERS OF THE VOLGA IN THE SUMMER-AUTUMN PERIOD OF 2012

2017 ◽  
pp. 65-73
Author(s):  
Edward Vladimirovich Nikitin
Keyword(s):  
Fish Species ◽  
Coastal Waters ◽  
Caspian Sea ◽  
The Caspian Sea ◽  
Volga River ◽  
Commercial Fish ◽  
Autumn Period ◽  
Fish Juveniles ◽  
Qualitative Characteristics ◽  
Shallow Coastal Waters

Shallow coastal waters of the Volga river is a flooded feeding area for fish juveniles of nonmigratory fish species. There takes place annual downstream migration of fluvial anadromous fish species from spawning grounds of the Volga river to the Northern Caspian Sea. The most important factors determining the number and qualitative characteristics of fry fishes are the level of the Caspian Sea (currently having a tendency to the lowering), hydrological and thermal regimes of the Volga river. Researches were carried out in definite periods of time. In the summer-autumn period of 2012 fry fishes were presented by 19 species (13 of them were commercial species), which belonged to 9 families. The article gives data on all the commercial fish species. In the first decade of July the maximum number of fry fish was registered in the western part of the Volga outfall offshore - in box 247 (19.86 mln specimens/km2), in the eastern part - in box 142 (20.4 mln specimens/km2). The most populous were roach, red-eye, silver bream and bream; size-weight characteristics were better in the areas remoted from the Volga delta. In the third decade of July the quantitative indicators of fry fish on these areas decreased, size-weight characteristics greatly increased. In the second decade of October in the western part of the seaside there were registered increased pre-wintering concentrations of fish juveniles, their qualitative indicators increased, which is evidence to favorable feeding conditions in 2012.

Numerical Study on Circulation and Thermohaline Structures With Effects of Icing Event in the Caspian Sea

2010 ◽  
Author(s):  
Daisuke Kitazawa ◽  
Jing Yang
Keyword(s):  
Numerical Simulation ◽  
Water Temperature ◽  
Coriolis Force ◽  
Caspian Sea ◽  
Numerical Study ◽  
Measurement Data ◽  
Ocean Model ◽  
Water Current ◽  
The Caspian Sea ◽  
Volga River

A hydrostatic and ice coupled model was developed to analyze circulation and thermohaline structures in the Caspian Sea. The northern part of the Caspian Sea freezes in the winter. Waters start icing in November and ices spread during December and January. The northern part of the Caspian Sea is covered by ices in severe winters. Ice-covered area is at its maximum during January and February, and then ices begin melting in March and disappear in April. The occurrence of ices must have significant effects on circulation and thermohaline structures as well as ecosystem in the northern Caspian Sea. In the present study, formation of ices is modeled assuming that ices do not move but spread and shrink on water surface. Under the ices, it is assumed that the exchange of momentum flux is impeded and the fluxes of heat and brine salt are given at sea-ice boundary. The ice model was coupled with a hydrostatic model based on MEC (Marine Environmental Committee) Ocean Model developed by the Japan Society of Naval Architect and Ocean Engineers. Numerical simulation was carried out for 20 years to achieve stable seasonal changes in current velocity, water temperature, and salinity. The fluxes of momentum, heat, and salt were estimated by using measurement data at 11 meteorological stations around the Caspian Sea. Inflow of Volga River was taken into account as representative of all the rivers which inflow into the Caspian Sea. Effects of icing event on circulation and thermohaline structures were discussed using the results of numerical simulation in the last year. As a result, the accuracy of predicting water temperature in the northern Caspian Sea was improved by taking the effects of icing event into account. Differences in density in the horizontal direction create several gyres with the effects of Coriolis force. The differences were caused by differences in heat capacity between coastal and open waters, differences in water temperature due to climate, and inflow of rivers in the northern Caspian Sea. The water current field in the Caspian Sea is formed by adding wind-driven current to the dominant density-driven current, which is based on horizontal differences in water temperature and salinity, and Coriolis force.

scholarly journals Impact of the European Russia drought in 2010 on the Caspian Sea level

2012 ◽  
Vol 16 (1) ◽  
pp. 19-27 ◽  
Author(s):  
K. Arpe ◽  
S. A. G. Leroy ◽  
H. Lahijani ◽  
V. Khan
Keyword(s):  
Sea Level ◽  
Caspian Sea ◽  
Analysis Data ◽  
Reanalysis Data ◽  
European Russia ◽  
Severe Drought ◽  
The Caspian Sea ◽  
Volga River ◽  
The Impact

Abstract. The hydrological budgets of the Volga basin (VB) and the Caspian Sea (CS) have been analysed. The components of the water balance for the CS were calculated for the period 1993 to 2010 with emphasis on summer 2010 when a severe drought developed over European Russia. A drop in precipitation over the VB in July 2010 occurs simultaneously with a decrease in evaporation for the same area, an increase of evaporation over the CS itself and a drop of the Caspian Sea level (CSL). The drop in the precipitation over the VB cannot lead to an instantaneous drop of the CSL because the precipitated water needs some months to reach the CS. The delay is estimated here to be 1 to 3 months for excessive precipitation in summer, longer for deficient precipitation and for winter cases. However, the evaporation over the CS itself is considered to be responsible for a simultaneous drop of the CSL from July to September 2010. The impact on the CSL from the precipitation deficit over the VB occurs in the months following the drought. The water deficit from July to September 2010 calculated from the anomalous precipitation minus evaporation over the VB would decrease the CSL by 22 cm, of which only 2 cm had been observed until the end of September (observed Volga River discharge anomaly). So the remaining drop of 20 cm can be expected in the months to follow if no other anomalies happen. In previous studies the precipitation over the VB has been identified as the main cause for CSL changes, but here from a 10 cm drop from beginning of July to end of September, 6 cm can be directly assigned to the enhanced evaporation over the CS itself and 2 cm due to reduced precipitation over the CS. Further periods with strong changes of the CSL are also investigated, which provide some estimates concerning the accuracy of the analysis data. The investigation was possible due to the new ECMWF interim reanalysis data which are used to provide data also for sensitive quantities like surface evaporation and precipitation. The comparison with independent data and the consistency between such data for calculating the water budget over the CS gives a high confidence in the quality of the data used. This investigation provides some scope for making forecasts of the CSL few months ahead to allow for mitigating societal impacts.

Two species of the genus Theristus Bastian, 1865 (Nematoda: Xyalidae) from the hypersaline water bodies of the Crimea (Azov-Black Sea basin)

Zootaxa ◽  
2020 ◽  
Vol 4881 (2) ◽  
pp. 372-382
Author(s):  
TATIANA N. REVKOVA
Keyword(s):  
Black Sea ◽  
Reproductive System ◽  
Caspian Sea ◽  
Water Bodies ◽  
The Caspian Sea ◽  
Crimean Peninsula ◽  
The Crimea ◽  
Hypersaline Water ◽  
The Crimean Peninsula

Morphological descriptions of two species of the genus Theristus Bastian, 1865 belonging to group flevensis, found in the hypersaline water bodies of the Crimean Peninsula, are presented. Theristus siwaschensis sp. n. is morphologically closest to T. flevensis Schuurmans Stekhoven, 1935, T. parambronensis Timm, 1952, T. macroflevensis Gerlach, 1954, T. metaflevensis Gerlach, 1955, but differs from them by the structure of the reproductive system in females, number of cephalic setae and size of spicules. Specimens of T. flevensis found in the Lake Chersonesskoye are similar to the re-description of a large forms of T. flevensis from Chile by Murhy (1966) and Caspian Sea by Chesunov (1981). However, it differs from the Caspian Sea species by having larger amphids, longer cephalic setae and spicules. T. pratti Murph & Canaris, 1964 and T. ambronensis Schulz, 1937 are synonymized with T. flevensis.

scholarly journals Checklist and Distribution of Calanoida (Crustacea: Copepoda) in Kazakhstan (Central Asia)

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2015
Author(s):  
Elena Krupa ◽  
Moldir Aubakirova
Keyword(s):  
Caspian Sea ◽  
Climatic Factors ◽  
Water Bodies ◽  
The Black Sea ◽  
The Caspian Sea ◽  
Small Water ◽  
Limnocalanus Macrurus ◽  
Acanthodiaptomus Denticornis ◽  
Inland Water Bodies ◽  
Far Eastern

This work aims to analyze the zoogeographic distribution of Calanoida in Kazakhstan. Kazakhstan belongs to the Palaearctic region, and its territory is ascribed to the European–Siberian and Nagorno–Asian biogeographical subregions. The European–Siberian subregion includes the Volga–Ural, Irtysh, and Turkestan–Aral provinces. The Balkhash province belongs to the Nagorno–Asian subregion. Studies of the Calanoida fauna were carried out between 1997 and 2019. For this purpose, 7250 zooplankton samples were taken in 130 different water bodies. Findings of 26 species of Calanoida have been documented. The richest in species composition (20) is the Calanoida fauna of the Irtysh province. Ten Calanoida species have been recorded in the Volga–Ural province, 8 in the Turkestan–Aral province, 7 in the Balkhash province, and 5 in the Ponto–Caspian region. The distribution of the species richness of the order is determined by a complex of climatic factors, including the density of the hydrographic network, a variety of hydrochemical conditions, and accidental acclimatization of species. Far Eastern species (Sinodiaptomus sarsi, Neutrodiaptomus incongruens, Neodiaptomus schmackeri) entered the inland water bodies of Kazakhstan, most likely through the introduction of non-native fish species. The Black Sea species Acartia tonsa and Calanipeda aquaedulcis were introduced into the Caspian Sea with ballast waters. Three autochthonous species (Limnocalanus macrurus, Eurytemora grimmi, Eurytemora minor), formerly inhabiting the Caspian Sea, can now be considered extinct. Acanthodiaptomus denticornis, Arctodiaptomus (R.) salinus, Phyllodiaptomus blanci, and Eudiaptomus graciloides are widespread in the region. Endemic species (Gigantodiaptomus irtyshensis, Arctodiaptomus naurzumensis) and species are new for Kazakhstan (Diaptomus (Chaetodiaptomus) mirus, Eudiaptomus transylvanicus, Arctodiaptomus dentifer, A. (Rh.) ulomskyi were found in small waterbodies; they are known only from single occurrence sites as well as Eurytemora caspica. The last one was described from the northern part of the Caspian Sea, in the coastal zone. Further research into small water bodies that are poorly studied may expand our knowledge of the diversity of Calanoida in Kazakhstan. Calanoida fauna of Kazakhstan was closest to the fauna of countries with a continental climate and most strongly differed from countries with subtropical and Mediterranean types of climates.

scholarly journals Interannual Variability of Water Exchange Anomalies Between the Northern, Middle and Southern Caspian Based on Satellite Altimetry Data

2019 ◽  
Vol 25 ◽  
pp. 106-115 ◽  
Author(s):  
Sergey A. Lebedev ◽  
Andrey G. Kostianoy
Keyword(s):  
Caspian Sea ◽  
Seasonal Variability ◽  
Satellite Altimetry ◽  
Water Exchange ◽  
Western Coast ◽  
Altimetry Data ◽  
The Caspian Sea ◽  
Volga River ◽  
Geostrophic Velocities ◽  
Satellite Altimetry Data

The paper presents the results of estimation of interannual and seasonal variability of water exchange between the Northern, Middle and Southern Caspian Sea based on the TOPEX/Poseidon and Jason–1/2/3 satellite altimetry data. The boundaries between the Caspian Sea sub-basins were taken along the 133 and 209 tracks of the satellites. Temporal variability of surface geostrophic velocities directed perpendicular to the tracks showed that positive values correspond to the southeast direction of the currents, negative values correspond to the northwest direction. It is clearly seen that the main water exchange associated with the Volga River runoff is concentrated along the western coast of the Caspian Sea. In this area, anomalies of geostrophic velocities exceed 20 cm/s. Total water exchange anomalies through the 133 and 209 tracks show seasonal variability with an amplitude up to ±18x105 m3/s for track 133 (a line between the Northern and Middle Caspian) and ±11x105 m3/s for track 209 (a line between the Middle and Southern Caspian). The maximum values of water exchange anomalies were observed in 1993, 1994 and 2012 through 133 track (±16-18x105 m3/s) and in 1993, 1996 and 1997 (±11x105 m3/s) through 209 track.

Astrakhan and Orenburg: Russia’s Asian Trade in the 17th and 18th Centuries

2020 ◽  
Author(s):  
Matthew Romaniello
Keyword(s):  
Caspian Sea ◽  
18Th Century ◽  
Direct Access ◽  
The Caspian Sea ◽  
Volga River ◽  
Trade Networks ◽  
Central Asian ◽  
The Pacific ◽  
Early Modern Era ◽  
Modern Era

Astrakhan and Orenburg were the Russian Empire’s two “official” entrances from Asia in the early modern era. Russia’s “Asia” was conceived broadly as the expanse of Eurasia from the Ottoman Empire to the shores of the Pacific. Russia’s control of the Volga River, culminating in the conquest of Astrakhan on the shores of the Caspian Sea in the 16th century, was intended to open direct access for Russia’s merchants to reach Asia. Throughout the 17th century, trade with the Middle East and Central Asia increased, followed by an important breakthrough in relations with China culminating in the Treaty of Nerchinsk in 1689. In the 18th century, Russia’s Asian trade increased; Astrakhan’s customs fees collected from Asian trade goods surpassed the revenue generated by Russia’s Baltic ports in the first half of the century. A growing trade with the Central Asian Khanates of Bukhara, Khiva, and Khoqand led to the creation of Orenburg as the entry point for overland trade from the steppe in 1753. In theory, the new outpost separated Russia’s “Asia” into separate zones for increased regulation: Astrakhan for goods arriving from the Caspian Sea, imported from Iran and India, and Orenburg for the increasing steppe traffic. This is not to suggest that increased regulation produced better control over Eurasia’s trade networks, but rather to reveal Russia’s significant investment in profiting from Asia’s trade as much as its competitors in Britain or the Netherlands did. While overland Eurasian trade remains plagued by a historiographical assumption of its decline in the 18th century, Astrakhan and Orenburg were vital centers of Eurasian commerce, revealing the robust overland trade that remained outside of West European observation.

Permafrost in the Caspian Sea basin in the Late Glacier Era as a possible trigger of the sea transgression: checking the hypothesis using a hydrological model

2021 ◽  
Author(s):  
Alexander Gelfan ◽  
Andrey Kalugin
Keyword(s):  
Sea Level ◽  
Caspian Sea ◽  
Catchment Area ◽  
Hydrological Model ◽  
Late Glacial ◽  
Volga Basin ◽  
The Caspian Sea ◽  
Volga River ◽  
Deep Freezing ◽  
Basin Area

<p>Paleogeographic data give grounds to assert that at the end of the Valdai Ice Age, transgressions of the Caspian Sea took place, and the sea level during these periods exceeded the current one by tens of meters. The physical mechanisms, climatic or others, that could have caused such an extreme sea level rise have not yet been established. At the same time, in the modern Volga basin, traces of very large ancient river channels are widespread, which could have been formed by ancient rivers with the water flow 2-3 times larger than the modern rivers. Thus, the hypotheses of the extreme rise in the Caspian Sea level can be reduced to considering possible sources of the increase in the flow of the ancient rivers. However, the question of possible sources of such a significant river flow remains open. At the end of the Paleocene - beginning of the Holocene, precipitation over the Caspian Sea catchment was not higher than now, the contribution of melted glacial waters in the Late Glacial Era was also insignificant.  Hypotheses about significant changes in the catchment area of the Caspian Sea during those times are not confirmed by paleogeographic data either. In our work, we test the hypothesis that the river inflow into the ancient Caspian Sea could significantly exceed the current inflow due to the spread of post-glacial permafrost over the sea catchment area, which contributed to a decrease in runoff losses due to infiltration into frozen soils.</p><p>The physical validity of the above hypothesis was tested using numerical experiments with a hydrological model of the Volga River basin, developed on the basis of the ECOMAG modeling platform. Assuming that the climatic conditions in the modern Volga basin area during the Late Glacial Era were close to the current conditions, numerical experiments were carried out to simulate deep freezing of soil throughout the entire territory of the modern Volga basin area. It is shown that under permafrost conditions, the Volga River runoff increases by 15-20% and does not provide a twofold rise in water inflow into the sea, estimated from paleogeographic data. At the same time, the experiments have shown that such extreme inflow of water into the Caspian Sea could be formed under the conditions of deep freezing of soils and in the absence of seasonal thawing of the frozen catchment area, i.e. at a colder climate than the modern one.</p>

scholarly journals Palaeostages of the Caspian Sea as a set of regional benchmark tests for the evaluation of climate model simulations

2012 ◽  
Vol 8 (5) ◽  
pp. 5053-5081 ◽  
Author(s):  
A. Kislov ◽  
A. Panin ◽  
P. Toropov
Keyword(s):  
Caspian Sea ◽  
Climate Models ◽  
Climate Model ◽  
Sharp Decrease ◽  
East European Plain ◽  
The Caspian Sea ◽  
Volga River ◽  
Model Simulations ◽  
East European ◽  
Climate Model Simulations

Abstract. Oscillations of the level of the Caspian Sea (CS) primarily stem from variations in runoff from the Volga River. Therefore, changes in the level of the CS can be used to assess the ability of climate models to reproduce the water budget over the East European Plain. We compare observed or reconstructed CS level positions during the Last Glacial Maximum (LGM), Holocene and modern periods with the CS level positions calculated based on simulations in experiments using the CMIP5/PMIP3 protocol. The proxy dataset comprises a number of detailed maps of the CS for the main regression stages and transgression stages during the last 30 ka together with information about sea-level positions. The results show poor correspondence between the model simulations of decadal- and centennial-scale level oscillations and proxy reconstructions. We propose that such discrepancies can be caused by insufficient sensitivity of the climate models used. The modelled data could be verified based on how well the models simulated the sharp decrease of the Volga River runoff during the LGM, which caused a large decline of the CS level.

scholarly journals European river lamprey Lampetra fluviatilis L. in the Baltic and Caspian seas basins of Tver region

2020 ◽  
pp. 7-15
Author(s):  
Анжелика Вячеславовна Колотей ◽  
Александр Олегович Звездин ◽  
Александр Васильевич Кучерявый ◽  
Дмитрий Сергеевич Павлов
Keyword(s):  
Caspian Sea ◽  
The Caspian Sea ◽  
Volga River ◽  
Lampetra Fluviatilis ◽  
Additional Information ◽  
River Lamprey ◽  
Species Expansion ◽  
Tver Region ◽  
The Baltic ◽  
Baltic Sea Basin

Представлена дополненная информация о распространении и условиях обитания речной миноги (Lampetra fluviatilis L.) на территории Тверской области. Ареал на территории области представляет собой сочетание исторического (водотоки бассейна Балтийского моря) и инвазионного (водотоки бассейна Каспийского моря) компонентов. Обоснована идея вселения миноги в систему р. Волга по системам искусственных судоходных каналов. Состояние популяций в Каспийском бассейне указывает на продолжающийся процесс освоения новых местообитаний. Additional information on the distribution and habitat of the European river lamprey (Lampetra fluviatilis L.) in the Tver Region is presented. The areal of the European river lamprey in the Region consists of the historical (watercourses of the Baltic Sea Basin) and invasive (watercourses of the Caspian Sea Basin) components. The idea of the lamprey invasion in the Volga River through the system of manmade shipping canals is substantiated. The condition of the lamprey’s populations in the Caspian Sea Basin indicates the ongoing process of the species expansion.

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