scholarly journals MODERN CONDITION AND PECULIARITIES OF DISTRIBUTION OF THE ZOOPLANKTON OF THE COASTAL AQUATORIA OF THE MANAS-OZEN OF THE CASPIAN SEA

2019 ◽  
pp. 6-11
Author(s):  
Magomed Magomedovich OSMANOV ◽  
Frangiz Shamilievna AMAEVA ◽  
Magomed Abdulaevich GURUEV ◽  
Murad Mukhtarovich ALIGADZHIEV ◽  
Ayshat Abdulmajidovna ABDURAKHMANOVA
Keyword(s):  
Caspian Sea ◽  
Biological Diversity ◽  
Water Area ◽  
Acartia Tonsa ◽  
Mnemiopsis Leidyi ◽  
Biological Productivity ◽  
The Caspian Sea ◽  
Positive Role ◽  
Modern Condition

The article presents the research data on the biological diversity and dynamics of the zooplankton complexes structure of the Manas-ozen of the Daghestan coastal water area of the Caspian Sea in modern conditions. It is noted that the formation of the zooplankton complex of the studied area is seasonal. The positive role of Acartia tonsa Dana in maintaining the biological productivity of the studied area under the conditions of Mnemiopsis leidyi A. Agassiz introduction is also noticed.

scholarly journals The ctenophore Beroe cf. ovata in the Caspian Sea. The beginning of a new stage in the evolution of the Caspian ecosystem?

2021 ◽  
Vol 15 (4) ◽  
pp. 21-35
Author(s):  
S. V. Vostokov ◽  
A. A. Gadzhiev ◽  
A. S. Vostokova ◽  
N. I. Rabazanov
Keyword(s):  
Caspian Sea ◽  
Size Structure ◽  
Mesh Size ◽  
Acartia Tonsa ◽  
The Black Sea ◽  
Mnemiopsis Leidyi ◽  
Breeding Cycle ◽  
The Caspian Sea ◽  
Small Copepod ◽  
The Impact

Aim. Analysis of the first data regarding the arrival of the predatory ctenophore Beroe cf. ovata in the Caspian Sea and assessment of possible effects of its introduction for the Caspian ecosystem.Material and Methods. The material was obtained in the deep-water region of the western shelf of the middle Caspian Sea in the first ten days of October 2020. Zooplankton samples were collected using a Juday plankton net (0.1 m2 opening, 180 μm mesh size). Large ctenophores were collected using a big cone plankton net (CB) with a 0.5 m2 opening, 500 μm mesh size. Samples were taken at five stations in the 0-40 m layer. Combs larger than 5 mm were counted and measured on board the ship. The number and size of small ctenophores, larvae and eggs were determined in zooplankton samples fixed with formalin to a final concentration of 4%.Results. The presence of a new alien Beroe cf. ovata was recorded in the Dagestan shelf waters of the Caspian Sea in the beginning of October 2020. The average number of Beroe cf. ovata for five stations was 22 ind/m2 and the biomass was 6.15 g/m2. Larvae and small individuals from 5 to 20 mm in size predominated. Mnemiopsis leidyi was absent in the area investigated. The structure of mesozooplankton was dominated by the small copepod Acartia tonsa, which accounted for 92% of the zooplankton community and 78% of its biomass.Conclusion. The size structure of the B. ovata population with a predominance of larvae and small individuals indicates a recently completed breeding cycle and adaptation of the ctenophore to the conditions of the Caspian Sea. The first impacts of the new invasive ctenophore on the population of M. leidyi were demonstrated. This event may be the beginning of a new stage in the evolution of the Caspian Sea ecosystem and the restoration of its bio resources affected by the invasion of Mnemiopsis leidyi. The structure of mesozooplankton with total dominance, in abundance and biomass, of the small copepod Acartia tonsa did not differ from that in the previous period, indicating that the Caspian zoocenosis did not respond to the short-term reduction of the impact of M. leidyi. A brief analysis of the history of the introduction of ctenophores to the Black and Caspian Seas is presented and their impact on ecosystems and biological resources of these seas is studied. Based on longterm observations of the invasive ctenophores' interactions in the Black Sea, the possible outcomes of the penetration of Beroe cf. ovata in the Caspian Sea are discussed.

scholarly journals HYDROBIOLOGICAL STUDIES OF PLANKTON COMMUNITIES OF MAKHACHKALA SEAPORT

2019 ◽  
pp. 12-18
Author(s):  
Magomed Magomedovich OSMANOV ◽  
Frangiz Shamilievna AMAEVA ◽  
Ayshat Abdulmajidovna ABDURAKHMANOVA
Keyword(s):  
Aquatic Organisms ◽  
Water Area ◽  
Acartia Tonsa ◽  
Anthropogenic Influence ◽  
The Caspian Sea ◽  
Spring Period ◽  
Brackish Water Species ◽  
Water Species ◽  
Plankton Communities ◽  
Planktonic Communities

The article presents data from spring hydrobiological studies in the Makhachkala l Seaport during the period of dredging. It is noted that plankton of the studied water area of the Caspian Sea is a typical community of the spring period, formed mainly by marine and brackish-water species of phytoplankton and zooplankton. Diatoms mainly dominate in phytoplankton, and Copepods in zooplankton, where the main dominant is the Azov-Black sea invader Acartia tonsa Dana,1843. The analysis of planktonic communities indicates a rather developed quantitative and qualitative community of aquatic organisms with a characteristic abundance of species inhabiting it in the spring, despite a significant anthropogenic influence. It is established that the ongoing dredging operations do not have a tangible effect on the productivity of planktonic organisms.

scholarly journals MICROALGAE FROM THE COASTAL WATERS OF TYULENY ISLAND IN THE CASPIAN SEA

2019 ◽  
Vol 14 (2) ◽  
pp. 120-131
Author(s):  
R. M. Barkhalov ◽  
A. A. Abdurakhmanova ◽  
F. Sh. Amaeva
Keyword(s):  
Coastal Waters ◽  
Caspian Sea ◽  
Biomass Concentration ◽  
Water Area ◽  
Trophic Chain ◽  
The Caspian Sea ◽  
Standard Procedures ◽  
Water Surface Layer ◽  
Rich Flora ◽  
Positive Effect

Aim. In this work, we set out to study the composition of a phytoplankton community in an important fishery area, the coastal water area of Tyuleny Island in the Caspian Sea.Methods. We present the results of seasonal observations (2016) on the state of phytoplankton in the coastal waters of Tyuleny Island in the Caspian Sea. In total, 120 phytoplankton samples were collected at four stations from the water surface layer (May–October) using the Nansen bottle and subsequent fixation by Lugolʹs solution. Sedimentation and concentration were carried out using standard procedures. The samples were processed in the Nageotte chamber with a volume of 0.1 ml under a light microscope.Results. According to the research results (2016), 103 species and varieties of microalgae were found in the phytoplankton samples collected from the water area of Tyuleny Island. The microalgae were represented by four divisions: Bacillariophyta – 49 species, Cyano‐ phyta – 24 species, Chlorophyta – 23 species and Pyrrophyta – 7 species. The greatest species diversity of phytoplankton in the studied water area was noted during the autumn period (61 spe‐ cies). In general, phytoplankton was found to be distributed homogeneously throughout the coastal area of the island, with the biomass concentration not reaching 1 g/m3.Conclusion. In 2016, favorable hydrological and hydrochemical conditions for the development of microalgae were observed. The desalinated water around Tyuleny Island, which is well warmed in the summer and does not freeze in the winter, contributed to the development of rich flora. Although bi‐ omass values were not high due to the prevalence of small‐celled microalgae in phytoplankton, in general, it should have a positive effect on the development of subsequent links in a trophic chain, as well as promote an increase in the productivity of waters of the Northern Caspian Sea. 

New Stage in the Geopolitical Struggle around the Caspian Sea after 1991

2021 ◽  
Vol 13 (1) ◽  
pp. 21-36
Author(s):  
Stanislav Aleksandrovich Pritchin
Keyword(s):  
Caspian Sea ◽  
Legal Status ◽  
Oil And Gas ◽  
Political Influence ◽  
Water Area ◽  
The Caspian Sea ◽  
Regional Powers ◽  
Complete Work ◽  
Strategic Goals ◽  
The Military

For almost three centuries, starting with the campaign of Peter the Great in 1721-1722, Russia has traditionally played a key role in the Caspian Sea. The situation changed dramatically with the collapse of the USSR in 1991 and the emergence of three new regional players-Azerbaijan, Kazakhstan and Turkmenistan. For Russia, this meant a significant reduction in influence in the region and the loss of control over most of the water area and the sea and its resources. In the historiography devoted to the region, the emphasis is placed on assessing the new round of geopolitical struggle, the position and interests of Western and regional powers. The author of this article provides a critical analysis of changes in Russian policy towards the Caspian Sea over the past 30 years and assesses the effectiveness of these changes. The difficult transition from the role of a dominant player in a region closed to external competitors to an open geopolitical confrontation over resources, their transportation routes, and political influence at the first stage was not in favor of Russia. Russia could not defend the principle of a condominium for joint development of hydrocarbon resources of the sea. With the active assistance of Western competitors, Russia lost its status as a monopoly transit country for oil and gas from the region. At the same time, thanks to diplomatic efforts and increased political dialogue with its neighbors in the region, Russia managed to resolve all territorial issues at sea by 2003, maintain the closed status of the sea for the military forces of third countries, and by 2018 complete work on the Convention on the international legal status of the sea, which established the principles of cooperation in the region that are important for the Russian Federation. Thus, official Moscow managed to achieve the strategic goals adapted after the collapse of the USSR by using the traditional strengths of its foreign policy and consolidate its status as the most influential player in the region.

HYDROGEOLOGICAL CHARACTERISTICS OF RESERVOIR WATERS OF THE CASPIAN SEA DEPOSITS

2021 ◽  
Vol 82 (3) ◽  
pp. 33-48
Author(s):  
NABIEVA VICTORIA V. ◽  
◽  
SEREBRYAKOV ANDREY O. ◽  
SEREBRYAKOV OLEG I. ◽  
◽  
...  
Keyword(s):  
Oil Recovery ◽  
Caspian Sea ◽  
Oil And Gas ◽  
Chemical Properties ◽  
Water Area ◽  
Water Soluble ◽  
Salt Composition ◽  
The Caspian Sea ◽  
Recovery Coefficient ◽  
Hydrogeological Characteristics

Hydrogeological conditions of reservoir waters of oil and gas fields in the northern water area of the Caspian Sea characterize the geological features of the structure of the Northern Caspian shelf, as well as the thermodynamic parameters of the exploitation of productive deposits, production and transportation of oil and gas. Reservoir waters contain water-soluble gases. According to the size of mineralization, the ratio of the main components of the salt composition, as well as the presence of iodine and bromine, reservoir waters can be attributed to a relatively "young" genetic age, subject to secondary geochemical processes of changing the salt composition in interaction with "secondary" migrated hydrocarbons. The physical and chemical properties of reservoir waters are determined by PVT analysis technologies. Hydrogeological and geochemical studies of compatibility with reservoir waters of marine waters injected to maintain reservoir pressures (PPD) during the development of offshore fields in order to increase the oil recovery coefficient (KIN) indicate the absence of colmating secondary sedimentation in mixtures of natural and man-made waters.

Eastern Conquests and Factionalism

2019 ◽  
pp. 169-193
Author(s):  
Brian Ulrich
Keyword(s):  
Caspian Sea ◽  
Driving Force ◽  
The Caspian Sea ◽  
Islamic World

This chapter begins by studying the role of al-Azd and the Muhallabids in the Islamic conquests along the eastern frontier of the Islamic world, in Khurasan and Sind. It critiques the idea that the Azd were a driving force behind the conquest of Sind, noting their prior presence in that region. Examining Yazid b. al-Muhallab’s campaigns in Jurjan and Tabaristan south of the Caspian Sea, it argues that both the Caspian and Sind campaigns were the result of governors linked to the Umayyad caliphs conquering territories to which their factional rivals had ties. Finally, there is a study of the role of al-Azd identity in Khurasan on the eve of the Abbasid Revolution.

Conclusion

2021 ◽  
pp. 206-228
Author(s):  
Stephen E. Gent ◽  
Mark J. C. Crescenzi
Keyword(s):  
Market Power ◽  
Caspian Sea ◽  
International Institutions ◽  
Policy Implications ◽  
Conflict Behavior ◽  
Future Research ◽  
Gray Zone ◽  
The Caspian Sea ◽  
Power Politics

This concluding chapter addresses some additional aspects of market power politics and outlines several implications of this study for scholars and policymakers. First, to complement the previous case studies of violence and strategic delay, it provides a brief discussion of Russia’s decision to abandon a delay strategy and agree to a settlement of the long-running dispute over the Caspian Sea. It then outlines a set of questions for future research on market power politics. Next, the chapter reflects upon how the research in the book informs an understanding of international relations. It highlights some important lessons concerning the effects of market structure on conflict behavior and the limitations of international institutions. It then contemplates the future role of gray zone tactics by countries like Russia and China. The chapter concludes with a discussion of some of the policy implications that follow from this research.

Iranian-Russian Relations in the Eighteenth Century

2018 ◽  
Author(s):  
Goodarz Rashtiani
Keyword(s):  
Eighteenth Century ◽  
Ethnic Minorities ◽  
Caspian Sea ◽  
The Caspian Sea ◽  
The Caucasus ◽  
The Difference ◽  
Political Economic

The main objective of the present chapter is to analyze the structure and features governing the relations between Iran and Russia in different political, economic, and social spheres in the period from the fall of Isfahan (1722) to the rise of the Qajar dynasty (1796) and to study the reasons for the difference in these relations compared to previous periods and Russia’s actions in Iran’s territory (the Caspian Sea and the Caucasus) with an emphasis on the developments in both countries, the role of ethnic minorities and local khanates, and the effect of regional and international conditions on the relations between the two countries.

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