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The INMIO-CICE hydrodynamic model of the Caspian Sea was used to calculate equilibrium river runoff and evaporation from the sea surface over a wide range of sea levels (from –85 to +50 m a.s.l.) for different climatic conditions: the Last Glacial Maximum (about 21 ka BP) and the pre-industrial climate (~1850). Data from the INMCM4.8 climate model were used as boundary conditions. It was found out that a river runoff of about 400 km3/yr was required in the Last Glacial Maximum to maintain the sea level at 35–50 m a.s.l. corresponding to the maximum values of the Khvalynian transgression. In the Last Glacial Maximum, evaporation from the sea surface decreased by 105–175 mm (12–22%), and a precipitation layer, according to the INMCM4.8 model, decreased by 50–70 mm (15–30%). These conditions caused the equilibrium runoff to decrease by about 10–20% compared to the pre-industrial conditions. Smaller absolute and relative changes corresponded to lower sea levels. The maximum evaporation decrease occurred at 5 m a.s.l. [ABSTRACT FROM AUTHOR]

Variations of physical properties of seawater (sound speed, temperature, salinity, and density) over the southern shelf of the Caspian Sea were assessed. Furthermore, the effect of monthly changes in physical structure and layering procedure was evaluated on water characteristics. The influence of the thermal structure and stability of the water column in warm months on the sound speed was greater than that of the salinity parameter. Due to the high correlation between sound speed and temperature in the Caspian Sea water, their vertical structures are mostly correlated. The range of surface layer water changes was within 9–30°C during different months of the year. The water salinity in the areas away from the coast was measured around 12 to 12.5 PSU. The range of measured sound speed data in February was about 1450–1463 m/s, while the values recorded in June‑July were between 1501–1451 m/s. The results indicated formation of a deep acoustic channel in the middle and deep areas of the seawater column. The analysis revealed that the axis of the sound channel occurs at a depth of 140–150 m (intermediate layer) in warm months. The axis of the sound channel was located in upper layers in the warm months. [ABSTRACT FROM AUTHOR]

We used the bycatch of Caspian sturgeon to quantify the species composition, length structure, spatial and temporal distribution, temporal dynamics of relative abundance (indexed as catch‐per‐unit‐effort, CPUE), effects of fingerlings released, and to forecast future sturgeon stock status. Dynamic factor analysis of temporal changes in species CPUE was used to quantify relationships to environmental variables (sea surface temperature, chlorophyll‐a, sea surface level, and river discharge) during 2006–2022. We found that the Guilan subarea had the lowest relative abundance and differed from all other subareas. Fish abundance was highest in October and November, particularly in Mazandaran and Golestan coastal waters. Relative fish abundance declined significantly over time. Acipenser persicus was the most abundant species, followed by Aciperser gueldenstaedtii, Aciperser stellatus, Aciperser nudiventris, and Huso huso. The annual number of fingerlings released decreased during 2000–2021. Over the years, environmental variables such as sea surface level, sea surface temperature, and chlorophyll‐a showed different trends, with sea surface temperature generally increasing, chlorophyll‐a generally decreasing, sea surface level decreasing nearly linearly, and river discharge varying erratically without a trend in the southern Caspian Sea during 2006–2022. The relative abundance of all species decreased and was significantly related to sea surface level. Fish abundance was forecasted to decline by 2025, as sea surface temperature increases and sea surface level decreases. Illegal, unreported, and unregulated (IUU) harvest of sturgeon must be effectively regulated to ensure the survival and recovery of sturgeon populations in the Caspian Sea. [ABSTRACT FROM AUTHOR]

Spawning potential ratio (SPR) is an important index used by fisheries biologists and managers to determine how a fishery should be harvested to prevent recruitment overfishing. In the southeastern Caspian Sea, Iran, 3430 common carp Cyprinus carpio were caught by beach seine in 2‐week intervals of two fishing seasons in 2019 and 2020. Fork length (FL) was measured to the nearest 1 cm. The age and maturity stage of 434 specimens, including 236 females and 198 males, were estimated by scale and gonad microscopic examinations. Estimated L∞ was 71.9 and K (growth constant) was 0.09. Instantaneous total mortality (Z) was 1.08, natural mortality (M) was 0.18, and fishing mortality (F) was 0.9. Estimated SPR at current fishing mortality (0.18) was lower than the reference point (0.4). Our findings indicated that fishing mortality should be reduced to F = 0.38 for C. carpio to meet the SPR reference point of 0.4. Further, higher minimum length limits should be set to reduce fishing mortality, and catch quotas for fishing cooperative corporations should be considered to meet the 40% SPR threshold. [ABSTRACT FROM AUTHOR]

This study examined the occurrence of microplastics (MPs) in the gastrointestinal tract (GIT) of 384 fishes classified into four species from 11 sites in 2022 from the southern part of the Caspian Sea. GITs of fishes were collected and digested in H2O2 and KOH at 45 °C for 72 h. After filtration, extracted MPs were observed under a stereomicroscope, and selected MP particles were identified using FTIR. Presence of MPs was 68.98% in the GIT of the investigated fish. The mean abundance of MPs was 5.9 ± 0.9 MPs/GIT in Rutilus kutum, 9.2 ± 1.2 MPs/GIT in Chelon auratus, 3.6 ± 0.7 MPs/GIT in Alosa braschnikowi, and 2.7 ± 0.5 MPs/GIT in Vimba vimba. The predominant form of MPs was fiber (58.21%), followed by fragment (34.77%). Black (34.4%), white (19.07%), and blue (14.58%) were the most frequently detected colors of MPs. Overall, 6 MP polymers were identified, dominantly polypropylene (42.86%), polystyrene (17.86%), and cellophane (14.28%). The western part of the Caspian Sea (mostly tourist spots and urban areas) showed more MP pollution in fish compared to the eastern part. Polymer hazard index (PHI) revealed alarming microplastic contamination in the southern Caspian Sea. The PHI value of the present study showed that PES (PHI = 8403.78) and PS (PHI = 535.80) were "Extreme danger" and "Danger" risk categories, respectively. [ABSTRACT FROM AUTHOR]

The purpose of this research was to evaluate the consumer’s behavior of farmed carp in the north of Iran (Golestan, Mazandaran and Gilan province).After defining the assumptions and designing the analytical-conceptual model based on the theory of planned behavior, a suitable questionnaire was developed and completed by the statistical community. In order to evaluate the intensity of the relationship between the research variables and the model elements, as well as to check the acceptance or non-acceptance of the assumptions, the structural equation modeling method (SEM) was used. Per capita fish consumption of farmed carp consumers is 5.3 kg. Of this amount, 400 grams are canned, 600 grams are consumed in restaurants and outside the home, and 2.5 kg are consumed at home. Per capita consumption of their farmed carp is 1.4 kg, so half of their consumption is from other fish. In this research, all hypotheses were confirmed, In this way, the effect of perceived usefulness, perceived risk and quality on attitude, the effect of normative beliefs, moral obligation and household income on subjective norms, the effect of control power, control belief, experimental records, advertising and education on the perceived behavior control, the effect of attitude, subjective norms and perceived behavior control on the decision to buy farmed carp and the effect of the decision to buy and perceived behavior control on the final behavior were reported to be significant (p<0.05). The values of the effect coefficients showed that the most effective variable on the attitude, subjective norms and perceived behavior control, is quality (with an effect coefficient of 0.46), income (with an effect coefficient of 0.44) and experience records (with an effect coefficient of 0.37), respectively. Also, among the three main elements of the model, the attitude had the greatest effect on the decision to buy and consume farmed carp (with an effect coefficient of 0.48). Factors such as improving quality indexes, increasing awareness about the usefulness of consumption, improving household income, recommendations from experts and relatives, purchase and consumption records of a member of the household, as well as advertising about farmed carp fishes can significantly help to increasing per capita consumption. [ABSTRACT FROM AUTHOR]

With the rapid development of aeromagnetic (primarily uncrewed) methods for measuring the magnetic field, the possibility of detailed magnetic research in hard-to-reach mountainous areas, forested areas, swamp areas, desert areas, and water areas has emerged. The conditions for interpreting the magnetic field are most difficult due to the vector nature of the magnetic properties of rocks, the wide range of their properties, and the presence of residual magnetization. The physical and geological conditions of the territory of Azerbaijan are characterized by rugged terrain relief, inclined magnetization (~58°), and complex geological environments. Along with using a probabilistic approach, deterministic methods for solving inverse and direct problems of geophysics become of great importance since it is possible to identify relatively extended reference boundaries and analyze magnetic anomalies from separate bodies of relatively simple shape. The article briefly outlines the main stages of processing and interpreting magnetic data under complex environments. The theoretical examples discussed include a block diagram of various disturbances, interpretive models of thin and thick beds, an intermediate model, a thin horizontal plate, and a horizontal circular cylinder on the flat and inclined surfaces under inclined magnetization conditions. The process of assessing magnetization on sloping terrain relief is shown. The presented field examples for the Caucasus Mountains show the quantitative interpretation of aeromagnetic data at the Big Somalit and Guton sites (southern Greater Caucasus, Azerbaijan), a deep regional profile through the Lesser and Greater Caucasus, magnetic field studies in the area around the Saatly superdeep borehole (Middle Kur depression between the Greater and Lesser Caucasus), and 3D magnetic field modeling at the Gyzylbulag gold deposit (the Azerbaijani part of the Lesser Caucasus). In the Caspian Sea, we demonstrated the use of an information parameter to identify faults in the Bulla hydrocarbon field (Gulf of Baku) and, for the first time, obtained the relationship between the generalized aeromagnetic data (2.5 kilometers over the mean sea level) and the central area of the mud volcanoes distribution in Azerbaijan. [ABSTRACT FROM AUTHOR]

In 2013-2023, the influence of the water level decrease in the Caspian Sea on the reproductive behaviour of the migratory-nesting species of Chroicocephalus ridibundus, Chlidonias niger, Chlidonias leucopterus, Chlidonias hybrida, Gelochelidon nilotica, Thalasseus sandvicensis, Sterna hirundo, Hydroprogne caspia which are in the Gizilaghaj Bay, was studied. Thousands of the migratory-nesting bird populations came to Azerbaijan from Africa and South-Eastern Asian countries and breed in the Gizilaghaj Bay of the Caspian Sea. As a result of the water level decrease in the Caspian Sea, the difference in the water level in the Northern and Southern parts of Little Gizilaghaj Bay caused a change in the reproductive behaviour of the species mentioned above of the Laridae family, which have been formed over many years. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of Ablai Khan KazUIRandWL: Series 'International Relations & Regional Studies' is the property of Kazakh Ablai Khan University of International Relations & World Languages and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Due to the multifactorial etiology, tumor manifestation in any vertebrate species may become a critical issue. This topic requires more consideration for species in aquatic ecosystems as an enclosed habitat. In addition, knowledge about oncogenesis in the aquaculture industry enhances the quality of products and its earned benefits. Objectives: This study investigated the tumor lesions, their characteristics, and probable causes, in the most commercially important fish in the southern Caspian Sea: Caspian white fish (Rutilus kutum). Methods: To accomplish this goal, after gross pathology of more than 20 cases, histopathological examinations and electron microscopic assays were employed. Results: The findings confirmed squamous cell carcinoma and squamous cell papilloma in the examined cases. Furthermore, the virus-like particles were clearly observed in the transmission electron microscopy results, indicating the probable viral etiology for these neoplastic lesions in Caspian Kutum. Conclusion: This study is the first to report the tumor prevalence in fish species of the southern Caspian Sea, which could be an alert for the mentioned ecosystem's health and the whole aquaculture industry. [ABSTRACT FROM AUTHOR]

Copyright of International Relations & International Law Journal / Seriâ Meždunarodnye Otnošeniâ & Meždunarodnoe Pravo is the property of Al-Farabi Kazakh National University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The proposed 'Vertical Gas Corridor' is a project that will directly challenge Russia's last remaining major gas pipeline Bratstvo - Brotherhood (Urengoy-Pomary-Uzhgorod route) into the heart of Europe. Bringing non-Russian gas into southern and central Europe via the Southern Gas Corridor has been a long-standing aim of the EU, regional EU member states, Turkey and gas producers as far afield as Central Asia and the Middle East, albeit with significantly differing agendas. Many projects, often grandiose, have been proposed over the years, often falling foul of the complex political and economic interests which crisscross the region. Russia's invasion of Ukraine in February 2022 provided yet another twist to this Levantine Great Game, creating both new impetus for supply diversification and new infrastructure options as the Kremlin's control over the pipelines originally built to bring gas west and south from Russia weakened. Now, under plans hatched by southeast and central European states, the region's growing gas interconnectivity could take another significant step forward, further weakening Russian gas Monopoly JSC Gazprom. The natural gas has only recently, since the 70s of the last century, turned into one of the main types of fuel. At the beginning of this century, about 88-90% of natural gas was delivered by gas pipelines under long-term economic contracts directly from a specific supplier to a specific customer, the rest - by tankers, in the form of liquefied gas (LNG). In 2021, global LNG imports, according to the report of the International LNG Importers Group (GIIGNL), increased by 4.5% compared to the previous year and reached 513.7 billion cubic meters (372.3 million tons). The group's research notes that in 2021, the LNG already accounts for about 40% of the global gas market, with the rest coming through gas pipelines. In 2021, about 73% of the LNG (375 billion cubic meters, or 271.8 million tons) was imported by Asian countries. In addition, only 36.6% of the world's LNG volume was sold on the spot market, i.e. in small lots, - the rest was sold through long-term contracts, thereby neglecting the market mechanism of free price formation. Due to the Russia-Ukraine war, the European Union's gas supply from Gazprom's pipelines was interrupted and Brussels is desperately looking for alternative routes. For the first time, the idea of such an alternative in the form of the "Trans-Caspian gas pipeline" was put forward by then US President Bill Clinton in 1996. However, due to the uncertainty of the status of the Caspian Sea and the lack of delimitation of its shelf boundaries, due to the conflicting position of Azerbaijan, Iran and Turkmenistan, this project was not implemented yet. After the annexation of Crimea in 2014 by Russia, the construction of one of the components of the "Southern Gas Corridor" (SGC) supported by the European Union - the "White Stream" gas pipeline and the liquefied gas project AGRI(LNG) initiated in 2007 - "Azerbaijan-Georgia-Ukraine-Romania-Hungary Interconnector" was postopned for an indefinite time. It should be noted that these were the most promising projects for Georgia and Azerbaijan, since both of them turned aside not only Russia, but also Turkey and, accordingly, neutralized its transit hegemony. This gas, passing through the SCP, was sent through the Trans-Anatolian gas pipeline and the Trans-Adriatic (TAP), from Turkey to Europe as one EU's South Gas Corridor (SGC). The Russia-Ukraine war has disrupted global supply chains and weakened the world economy, but it provides a new opportunity for Azerbaijan. In particular, as the US and Europe impose sanctions on Russian oil and natural gas, Azerbaijan has a chance to increase gas exports through 2022 and in the coming years via the 3,500-kilometer Southern Gas Corridor (SGC), which runs through seven countries and supplies gas to southern Turkey. Azerbaijan currently supplies 10 billion cubic meters of gas to Europe and 6 billion cubic meters - to Turkey, through the SGC. To meet the growing demand of Europe, Azerbaijan is also developing two new gas fields and is open to investment to expand the capacity of the SGC, in particular, by installing additional compressor stations, it will be possible to double the gas flow. However, according to the Azerbaijani Ministry of Economy, "reduced investment" from Europe may slow down the country's efforts to increase supply. Therefore: -The role of the "Southern Gas Corridor" in the context of the Russia-Ukraine war, and, consequently, the transit importance of Georgia for the EU energy security will increase even more; - The "corridor" will provide the Caspian countries with new, increased opportunities for the export of energy resources to the world market and will have a significant impact on the security and stability of the region; The Vice Prime Minister, Minister of Economy of Georgia, Mr. Levan Davitashvili, stated at a briefing held on November 21, 2022 that the Georgian government is working on a project to supply gas from the Caspian Sea shore of Azerbaijan to Europe through Georgia. According to Mr. L. Davitashvili the project, in which Azerbaijan, Romania and Hungary also participate, already have been started in 2015 and provides for a plan by which "... gas will be liquefied on the territory of Georgia, and then it will be re-gasified in Romania." Unfortunately, this project was stopped and had no further development", he said, adding that "... Europe is especially interested in alternative sources of gas supply, when everyone is talking about diversification of energy supply. This project has gained special relevance this year". Mr. L. Davitashvili noted that the evaluation of the project and the infrastructure in the territory of Georgia-Azerbaijan is underway. "It won't happen in a day or a year," he said, adding that "...first, we need to depict a complete picture...then we need to formulate a detailed action plan...and start implementing this plan step by step, including attracting investments." At the same time Azerbaijan's oil is in decline, but gas is growing. The future of Azerbaijan and Georgia energy cooperation is with natural gas EU's SGC and the Black Sea LNG terminals.Special attention should be paid to the prospects of supplying liquefied natural gas from Azerbaijan via Kulevi, Georgia to Romania from the SOCAR's BST Ltd. [ABSTRACT FROM AUTHOR]

During the Quaternary, the Lower Volga region was typically a shallow shelf of the Caspian Sea. This region regularly and distinctively responded to sea level fluctuations by changing both sediments and biota. This region is therefore a key to understanding the history of the transgressive-regressive cycles of the Caspian Sea during the Quaternary. There is a wealth of information about the Quaternary deposits of the Lower Volga region; however, their diversity of facies, erosional processes, and fragmented sections create difficulties in stratigraphic interpretation and the development of paleogeographic models. The studied 500-m section of borehole 8 Ulan-Khol is among the few in the Caspian region that allows for the sequential reconstruction of the Quaternary history of the region in one section. These borehole data offer a unique opportunity to reconstruct transgressive-regressive cycles in Pleistocene basins located in the most southeastern part of Europe (the Caspian region). Based on biostratigraphic, sedimentological, and paleomagnetic methods, we were able to define main Early, Middle, and Late Pleistocene units, which were correlated with regional stratigraphical units. Each unit corresponds to regional paleogeographic events and sedimentation modes characterized either by basinal (brackish water) or continental conditions when lagoons and fluvial landscapes dominated. The borehole interpretation integrated with regional data demonstrates a complex history of Caspian basin development during Apsheronian time (MIS 63–20) with the presence of a strong regression in its final stage, accompanied by a previously unknown advance of the Paleo-Volga valley to the latitude of Astrakhan city and further south. This regression and the formation of the Paleo-Volga valley continued during Tyurkyanian time (MIS 19). By the end of the Tyurkyanian, the regression was followed by a transgressive stage, which culminated in Bakunian time (MIS 18–12). The Khazarian stage (MIS 11–5) of Caspian Sea development was characterized by a constant change from alluvial-marine to marine and estuarine environments. The borehole data support our earlier conclusion that the Singilian deposits separate the lower (MIS 11–7) and upper (MIS 5) Khazarian units. New data support the existence of only one transgression of the Caspian Sea during Khvalynian time (MIS 3–2); after its maximum stage the sea level gradually decreased with the formation of coastlines at several terrace levels. Due to its high deposit thickness and rich paleontological, stratigraphic and lithological information, Ulan-Khol borehole 8 can be considered a key site for the Northern Caspian area. [ABSTRACT FROM AUTHOR]

In recent years, the effects of human activities and climate change on river flow patterns have become a major concern worldwide. This is particularly true in the southern Caspian Sea (SCS) region of Iran, where increasing water-intensive socio-economic development and climate change have significantly altered river flow regimes. To better understand these changes, this study employs two nonparametric methods, the modified Mann-Kendall method (MK3) and Innovative Trend Analysis (ITA), to examine spatial and temporal changes in hydrometeorological variables in the SCS. The study also evaluates the impact of human activities and climate change on river flow alteration using elasticity-based methods and the Budyko hypothesis in 40 rivers on the closest gauges to the Caspian Sea. The results indicate an alarming trend of increasing temperature, potential evapotranspiration, and decreasing river flows in the SCS region. In particular, human activities were found to be responsible for around 91.7 % of the change on average, resulting in a significant decline in inflow to the Caspian Sea by about 3216 MCM annually. This declining trend in inflow could potentially exacerbate the eutrophication conditions in the Sea and negatively impact its ecosystem and economics. Therefore, appropriate measures need to be taken to address these environmental and socio-economic issues in the southern Caspian Sea region.

Coastal aquifers are one of the most important sources of water supply, and it is expected that the effects of climate change will be one of their threatening factors in the short or long term. The present study was conducted in the northern coasts of Iran (Amirabad, Babolsar) and the main goal was to investigate the behavior of saltwater advance in coastal aquifers considering the changes in the coastline due to the effects of climate change and aquifer characteristics. In order to simulate the flow of underground water and the advancement of salt water in the coastal aquifer of the Caspian Sea, MODFLOW MT3DMS and SEAWAT numerical models were used in the GMS10.6 software. The results show that there is a salinity increase of up to 60 ppt, which is much higher than the minimum seawater salinity of 2 ppt. According to the results, it is clear that in the studied area, contaminated water entered the underground aquifers, especially in the coastal erosion areas and during the seasons when the sea level changes and when the changes in the coastline increase. HIGHLIGHTS Investigated the vulnerability of the aquifer by considering the changes in the water level due to climate change.; For this purpose, the images in the GIS environment were drawn to create a conceptual model.; After georeferencing the images, the values are assigned and then transferred to the GMS software.; It can be seen that the amount of water pollution increases every month.;

Azerbaijan, which is an oil/ gas-rich country, has been taking full advantage of its energy potential and taking steps towards creating green energy and turning it into an export. The Green Energy Corridor, in which Azerbaijan plays the main role, aims to connect Azerbaijan with Europe in its first stage. In the second stage, this corridor will connect Central Asia with Europe, which will involve the laying of an electric cable under the Black Sea and the Caspian Sea. This will allow Azerbaijan and other Central Asian countries to export zero-carbon electricity to the European market. If Azerbaijan is successful in this field, it will not only serve the sustainability of the country’s economy in the post-oil era, but will also contribute to the reduction in carbon emissions, leading to global benefits. The aim of this article is to assess the socioeconomic, ecological, and political benefits of green energy deployment in Azerbaijan. An economic cost-effectiveness analysis was conducted for selected green energy projects (large-scale wind and solar power plants). We also argue that green transition projects, which seem expensive and difficult to realise today, will be justified in the near future.

Recent geopolitical events have thrust the Caspian region into a time of unparalleled opportunity. Specifically, the Middle Corridor (“MC”) has been presented as a potential savior for trans-Eurasian commerce. At the same time, its success relies on a sea that is in an ecologically precarious state. Saving the Caspian for all future uses, including trade, will require unprecedented engagement and coordination amongst all its bordering states. This paper proposes a strategy for using the newfound focus on the MC to highlight its inherent connection to the Sea’s ecological precarity – thereby linking strategies of developing Trans-Caspian commerce with the efforts to preserve the Sea’s ecology against both existing and emerging threats. The paper begins by summarizing recent geopolitical developments connected to the MC that have accentuated the Caspian’s global importance for commerce. It then explores a related challenge – the simultaneous efforts of several littoral states to pursue desalination of Caspian seawater at a time when the Sea’s level is already declining from pre-existing causes. While these are two separate issues, we argue that they are, in fact, interrelated and that the coordination and governance challenges for improving commerce are very similar to those necessary for regulating desalination. Next, we analyze the challenge of regulating desalination in the context of water geopolitics and the unique features of the current Caspian Treaty. Finally, we review the language of the existing Caspian Treaty to identify areas where enhancements are necessary to better reflect both emerging challenges.

The archaeological site of Khaneh-sar 1 represents a geological facies comprising Pleistocene deposits situated southeast of the Caspian Sea, approximately 700 meters east of Komishan Cave. Predominantly comprised of chert stone artifacts, with a minor portion characterized by fine-grained dark brown soil, which, in terms of density, type, and color, resembles paleosols within the loess layers prevalent in the region. Comparable geological deposits include those of the Early Khvalynian. Through the implementation of a Systematic Random Sampling method, a total of 4992 artifacts were recovered from this site. Given the inherent distinctions between Khaneh-sar 1, the Aurignacian of Garmrud-2, and the Zagros industries, the lithic assemblage analyzed in this study is identified as a local industry representative of the intermediate Middle-to-Upper Paleolithic era in Iran. Consequently, considering the techno-typological attributes, geological context, alongside late Pleistocene climatic events, the formation of Khaneh-sar 1 is postulated to have transpired during the late middle to early Upper Paleolithic period, coinciding with Marine Isotope Stage 3 (MIS3), Khvalynian transgressions, and the CB horizon of Neka Loess. Thus, the genesis of Khaneh-sar 1 can be traced back to the intermediate Middle-Upper Paleolithic, aligning with the MIS3 [ABSTRACT FROM AUTHOR]

Prehistoric investigations in the southeastern region of the Caspian Sea commenced more than a century ago, resulting in the identification of several prominent archaeological sites, notably the caves of Kamarband, Hotu, Komishan, and Altappeh. These caves have become well-known for their rich archaeological deposits, spanning from approximately 16,000 years ago in the Mesolithic period to the Historic period. Hotu Cave, situated on a cliff along the northern slope of the Alborz mountain range, gained significant attention following its initial excavation in the 1950s by Carleton S. Coon. Excavations conducted over two field seasons lasting nine weeks each revealed valuable insights into the region's prehistoric occupation. In 2021, a team led by Hasan Fazeli from the University of Tehran undertook the re-excavation of Hotu Cave, unearthing 124 archaeological contexts spanning from the Mesolithic to the Historic period. Among the notable findings were 1,539 chipped stone artifacts, predominantly crafted from locally sourced Behshahr chert. The chipped stone assemblage from Hotu Cave exhibits distinctive characteristics indicative of different periods, including pressure removal technique evident in blade-lets and sickle trapezoids dating back to the Neolithic period, alongside ubiquitous scrapers and notched-denticulated tools found across all layers. Technological shifts within the chipped stone assemblage, observed during the recent excavations, reflect changes in subsistence patterns inferred from archaeozoological research on animal remains. However, the interpretation of these technological and subsistence changes is nuanced, as it remains unclear whether they occurred locally and gradually or resulted from external influences, such as demographic movements or the diffusion of ideas from neighboring regions. The chronological gap between the Mesolithic and Neolithic periods complicates the determination of the precise mechanisms driving these transformations solely based on material evidence from Hotu Cave. Further interdisciplinary research integrating archaeological, chronological, and environmental data is warranted to elucidate the dynamics of cultural change in this region during the transition from the Mesolithic to the Neolithic period. [ABSTRACT FROM AUTHOR]

Background: Rivers are an increasing source of MPs (microplastics) destined to the marine environments. Gorganroud River is passing through many kinds of land uses; including agriculture, forest and urban areas and could be one of the MPs pollution drivers to the Caspian Sea. Method: The abundance and distribution of MPs in sediments and some fish of the Gorganroud River assessed. Also, characteristics of microplastics with attached elements revealed and confirmed by SEM, EDX, ATR and Raman analysis. Results: The average abundance of MPs along the River sediments ranged from 220 ± 66 to 2460 ± 444 items/Kg. The most abundant of MPs reported from stations situated in urban areas, which suggests great amount of MPs in the Gorganroud River originates from cities wastewater effluents. Over 80% of these MPs was less than 2 mm. What's more, the majority shapes of MPs were fiber, followed by fragment and film. Black and gray were the dominant color among sediment MPs. Whereas the most common polymer types of these MPs in sediments were polypropylene (39%), polyethylene (26%), polyamide (16%), polystyrene (14%) and polyester (5%). Main type of polymers found in the digestive tract of fish were polypropylene (37%), polystyrene (29%), polyethylene (25%) and polyester (9%). Regard to the fish, the most abundant MPs detected in Neogobius melanostomus (0.72 n/g) caught mainly from stations situated along areas of agricultural fields. The same as sediment samples, prevalence shapes within digestive tract identified as fibers, followed by fragments and films. Although MPs size ranged from 0.1 to 3 mm, dominant MPs size was less than 1mm. Moreover, the frequent color detected within fish digestive tract was black. Conclusions: This survey demonstrated characteristics of MPs contamination along the Gorganroud River and revealed significance of the River as a sinking MPs pathway to the Caspian Sea ecosystem. [ABSTRACT FROM AUTHOR]

The research aimed to assess the influence of atmospheric processes in the Northern Hemi-sphere's Atlantic-European Sector on the Caspian Sea level based on the data for the days with Wangenheim-Girs atmospheric general circulation forms. The inputs covered the time period from 1900 to 2022. The information on the sea level, precipitation and ice events were harvested from 22 observation points in Kazakhstan and Russia. The statistical and comparative analysis as well as the climate change assessment within the framework of the study pointed to a stable correlation between the sea level and atmospheric circulation; re-vealed certain patterns reflected in precipitation distribution and frequency of moisture defi-cient and excessive years. The research also identified that the climatic changes have al-tered the sea's ice regime, with the maximum ice thickness decreasing by 13-28 cm depend-ing on a specific water area. In addition to ice thickness variation, the recent decades show an increased frequency of moderate and mild winters, and the shift of the main glaciation dates, i.e. a stable ice cover forming later, the date of fixed maximum ice thickness observed in mid-February, the date of complete ice clearing observed in early-mid March, and the freezing period being shorter. [ABSTRACT FROM AUTHOR]

The nervous system and its development play a crucial role in fish survival, locomotion and adaptation. Rutilus frisii kutum is one of the ecologically and economically important fish species of the Caspian Sea which is annually cultured and released in the Caspian Sea as millions of fingerlings. In order to investigate the nervous system structure of the Caspian Kutum, Rutilus frisii kutum, fingerlings were studied through histology technique. Results showed that the nervous system of the fingerlings is well developed, and composed of central (brain and spinal cord) and peripheral (nerves and ganglia) nervous tissue. The brain showed the normal structure of a ray-finned bony fish as in other teleosts, which shows that the fingerlings have the complete nervous system for facing and adapting to the new environment after release to the sea. [ABSTRACT FROM AUTHOR]

Invasion of ctenophore Mnemiopsis leidyi A. Agassiz, 1865 in the Caspian Sea in 1999 caused a major degradation of its ecosystem at all trophic levels, including fish resources due to an absence of any its predators. Supposedly, the recent invasion of another ctenophore, Beroe ovata Bruguière, 1789, which is highly specific predator of M. leidyi, will launch the recovery of the Caspian ecosystem. This assumption is based on the previous Black Sea positive experience and argued in this study with the recent field investigations of M. leidyi and B. ovata in the Caspian Sea off the Azerbaijan coast and summary of newly published relevant data on records of B. ovata in the Caspian Sea. [ABSTRACT FROM AUTHOR]

The article discusses the international legal status of the Caspian Sea and analyzes the provisions of the current instruments of international law entered into by Russia and the other Caspian littoral states (Azerbaijan, Iran, Turkmenistan, Kazakhstan). The authors study the provisions of the Framework Convention for the Protection of the Marine Environment of the Caspian Sea (Tehran, November 4, 2003) and the Convention on the Legal Status of the Caspian Sea (Aktau, August 12, 2018), express a number of constructive suggestions for the further development of the international cooperation between the Caspian littoral countries, including the establishment of an intergovernmental coordination body, and propose its powers for discussion. Since the implementation of international instruments involves the development of national legislation, the authors of the article conduct a comparative legal study of environmental legal acts of the five Caspian littoral states and identify their similarities and differences as well as advantages and disadvantages of the national approaches to the protection of the Caspian. They note that the international instruments aimed at regulating the use and protection of the natural resources of the Caspian do not mention the goal of joint movement of the Caspian littoral states to the transition to green economy standards and the objectives of sustainable development are formulated in them in a formal way. The authors substantiate the reasonability of developing model laws for the Caspian littoral states, which will consolidate their efforts to protect the nature of the Caspian. [ABSTRACT FROM AUTHOR]

Copyright of Iranian Veterinary Journal is the property of Shahid Chamran University of Ahvaz and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of History / Habaršy Tarihi Seriâsy is the property of Al-Farabi Kazakh National University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Measurements of Sulak River plume parameters in the Caspian Sea conducted from June 2 to 7, 2023, concurrently with satellite survey allowed tracing changes in water turbidity (WT) and suspended particulate matter (SPM) concentration in the near-mouth zone after the arrival of mudflow masses into the sea. Heavy rains in the mountains of Dagestan on May 31, 2023, caused mudflows, which entered, in particular, the Sulak River. Two days later, on June 2, mud masses, together with river water, flowed into the Caspian Sea. In the near-mouth zone, WT values exceeded 1000 NTU, which was beyond the allowable threshold of a portable turbidimeter employed for turbidity measurements. On June 2, 4, 5 and 7, quasi-synchronously with satellite imaging, measurements were conducted from a small boat using various oceanographic equipment. They were accompanied with water sampling for further determination of SPM concentration and mineral composition. The linear dependence revealed between WT and SPM concentration made it possible to calculate WT that could not be measured in situ: it amounted to 1247 NTU at SPM concentration of 1097.4 g/m3. Satellite data were used to compile WT maps using the Dogliotti 2015 algorithm. The results of satellite observations and in situ measurements showed that, within 2 days, WT and SPM concentration at the nearest to the river mouth station dropped sixfold and continued to decrease to the average values for this area in early June. Determined by X-ray phase analysis, the mineral composition of suspended solids on the day of mudflow arrival into the sea was represented mainly by clay minerals, their content reaching 75%. Later, by June 7, the mineral composition returned to the average values and the content of clay minerals did not exceed 44%. [ABSTRACT FROM AUTHOR]

The latitudinal distribution of the ctenophores Mnemiopsis leidyi A. Agassiz, 1865, and Beroe ovata Bruguière, 1789, in the Russian sector of the Caspian Sea has different boundaries for their ranges. Studies on the occurrence of ctenophores in the water column have demonstrated that each species has a characteristic temperature limit of its vertical distribution. Studies of interactions between ctenophores showed considerable suppression of the abundance of M. leidyi (particularly of smaller individuals) by B. ovata. [ABSTRACT FROM AUTHOR]

The study is Considering the importance of the role of benthic communities in evaluating the ecological status of aquatic ecosystems and part of a research project in the southern coasts of the Caspian Sea (depths less of 30 meters) was conducted in 2019. The aim of this study was investigation of the distribution, density and biomass of macrobenthos organisms in the water at a depths of 5, 10 and 30 meters south Caspian Sea. Sampling was seasonaly at eight with using Van Veen Grab. Overall 34443 organisms of Polychaeta including 3 families, 4 genuses and 4 species. The results showed that the highest density at Sefidrood station with mean of 327±27.71 N/m² and lowest was at Bandartoraman station with mean 77±5.33 N/m². The highest of Polychaeta was in summer and depth 30 meters with mean 285±26.18 N/m² and lowest density in spring and depth 10 meters with mean 38±10.81 N/m². The highest biomass was in spring and depth 30 meters with mean 0.23±0.02 g/m². The highest species was assigned to S. gynobranchiata with mean 352±19.74 N/m² and frequency 80%. In general, the results showed that in most seasons of the year, S. gynobranchiata was the dominant Polychaeta species. [ABSTRACT FROM AUTHOR]

Samples caught by beach seine nets in the fishing season of 2019-2021 in the southern costal zones of the Caspian Sea were used to study reproductive biology of Cyprinus carpio. Totally, 435 sea carp, including 237 female and 198 male were sampled, and their age and maturity stages were determined over sampling period. The results indicated that age range of the sampled C. carpio varied from 1 to 6 years in males, from 1 to 9 years in females, and from 1 to 9 years in combined sexes. The highest frequency of samples was in the age group of 1 for males (54.4%), 2 for females (34%), and 4 years for combined sexes (26.6%). Frequency of fish observed in the V and VI maturity stages was 45.14% and 27.17%, respectively. According to the frequency of different maturity stages and also the trend of changes in Gonado-somatic index (GSI), two spawning peaks were observed in C. carpio, including weak peak occurred in December-January and strong peak observed in March-April. The female mean length at sexual maturity (Lm50%) was 27.7 cm. Absolute and relative fecundity (mean ± SD) of C. carpio were 429310±233479 and 668±319 eggs, respectively. Since, there was an overlap between the spawning peak of C. carpio and beach seine fishing period for bony fish, it is proposed that fishing season to be banned at the beginning of April. [ABSTRACT FROM AUTHOR]

This study reports the isolation of the yeast Saccharomyces cerevisiae Dag-1 (OQ107063.2) from the seawater of the Caspian Sea, specifically from the coastal territory of the Samursky Reserve, Republic of Dagestan, Russia. The strain’s diagnostic and genetic characteristics are provided. Morphological features of the S. cerevisiae Dag-1 include round cells measuring 5.0×5.0 and 1.0×1.0 µkm in size. On Sabouraud’s media, it forms round, convex, opaque, creamy, glossy colonies with a diameter of 3-5 mm. The isolated strain demonstrates the ability to thrive in seawater with a salinity ranging from 12.8-13.0‰, across various temperature ranges (0 –+10, 23- 28, 35-40, 30-37°C), and under different pH conditions (5.6; 8.4-8.5). Additionally, it utilizes monomeric sugars (L-glucose, D-mannose, D-sucrose, D-arabinose, D-cellobiose, and D-xylose) as a source of carbon and energy, also metabolizing alcohols such as D-sorbitol, D-mannitol, and Dinositol (vitamin B8). The strain does not absorb the amino acids lysine and ornithine, and it is catalase-, amylase-, and β-glucosidase-positive while being urease-, oxidase-, and β-galactosidasenegative. Moreover, the strain exhibits high sensitivity to the antibiotics of ketoconazole, nystatin, clotrimazole, fluconazole, and itraconazole. Resistance is observed against the inhibitor potassium tellurite and pathogenic bacteria Escherichia coli, Staphylococcus aurens, and Klebsiella oxitoka. These findings contribute to expanding our understanding of the ecological distribution of marine yeasts and the isolation of an S. cerevisiae strain possessing characteristics of industrial microorganisms. [ABSTRACT FROM AUTHOR]

The presence of water resources, particularly rivers, significantly influences site selection. Throughout history, settling near rivers has brought numerous advantages, but it has also posed certain risks. This study focuses on the subbasins southeast of the Caspian Sea. Initially, we explore the connection between the layout of ancient settlements and the drainage networks. Additionally, we analyze the relationship between flood risk and the settlement patterns of these ancient sites by estimating the flooding risk based on linear, areal, and relief aspects. This research marks the first time such an analysis has been conducted. The findings underscore the importance of proximity to rivers in site selection, with areas close to rivers with lower stream orders being the most favorable for settlements. The study reveals a decrease in the frequency of sites near higher stream orders in relation to flooding risk. Conversely, there is an increase in the frequency and density of ancient sites near the first stream orders and at greater distances from the rivers, coinciding with an elevated flooding risk in the sub-basins. These results indicate that the inhabitants of the southeastern areas of the Caspian Sea sub-basins were cognizant of the flooding danger and factored it into their decision-making when selecting settlement sites. [ABSTRACT FROM AUTHOR]

The stock status of most fisheries resources is not well-known, which is associated with limited data available for stock assessment. To overcome this gap, several data-limited stock assessment models, including the surplus production model, were applied to estimate stock status of these data-limited resources where no sufficient data is available to apply the conventional stock assessment models. To estimate MSY, catch and CPUE data for Cyprinus carpio caught from the southeastern Caspian Sea were applied. Twenty-two years data (1999-2022) were analysed by SPM to estimate MSY. Three parameters including population growth rate (r), population carrying capacity (K), and initial biomass for an exploited population (Binit) required for estimating MSY were guessed 0.075 (/yr), 6952 tones, and 3500 tones, respectively by the catch-MSY model. The estimated MSY using these guessed parameters by SPM was 130 tones. While, estimated MSY using the repeated (multiple) starting points was 1320 tones. Phase plot indicated that the current status was both below the limited and the target biomass reference points. These illustrated the stock of C. carpio in the southeatern Caspian Sea is unsustainable and overfished. Since, survival of C. carpio depends the releasing hatchery reared juveniles to the wild, specific fisheries management should be applied to prevent the undersize catch and illegal fishing. [ABSTRACT FROM AUTHOR]

In Iran, studies of the transition from hunting and gathering to farming and herding have focused on early developments in the Zagros Mountains. Here, the authors present new zooarchaeological data from Hotu Cave, which throw light on sheep/goat management and domestication during the Epipalaeolithic--Neolithic transition on the southern shores of the Caspian Sea. Gazelle dominate the Epipalaeolithic levels, while sheep/goat are most abundant in the Neolithic. Large quantities of perinatal sheep/goat remains from the Early Neolithic indicate that these animals were actively managed in or close to the cave. The results point towards the importance in Iran of local developments beyond the Zagros, adding nuance to the general model of domestication in South-west Asia. Keywords: South-west Asia, Iran, Epipalaeolithic, Neolithic, animal domestication, zooarchaeology, Introduction The transition from hunting and gathering to farming and herding is one of the most important episodes in human history. Rather than a sudden revolutionary change, subsequently spreading out [...]

Abstract Human activities such as dam construction can lead to significant river flow regime changes and, consequently, river environments and habitats. Different approaches for estimating the environmental flow have developed to improve the river ecosystem's environmental and habitat conditions. The hydrological approach is considered in many studies to estimate environmental flows considering its advantages. Vimba vimba persa is an economically and ecologically valuable species in the Caspian Sea that spawns and reproduces naturally in the Gorganrood River downstream in April–May. After the construction of the Voshmgir dam on the Gorganrood River, the fish population has drastically reduced in recent decades. In this study, to investigate the effect of constructing the Voshmgir dam on the environmental flow of Gorganrood River, a wide range of hydrological methods, including Tennant, Tessman, Arkansas, Aquatic Base Flow, Flow Duration Curve, High Flow-Low Flow, and FDC Shifting have been used. Comparing the correlation between the mean monthly flow time series before and after the Voshmgir dam demonstrates remarkable changes, including Pearson (0.95 to 0.86), Spearman's rho (0.93 to 0.78), and Kendall's τ (0.78 to 0.61) as a consequence of dam construction. The results indicate that estimated environmental flow from Tennant (1.1, 3.4 to 1.3, 3.8 cms) and Aquatic Base Flow (0.5 to 1.8 cms) methods have led to inadequate estimation due to significant changes in flow in different months. The amount of environmental flow during April–May estimated from investigated methods indicates the dam negatively affected water allocation to meet the river downstream's ecological and environmental needs. The flow duration curve analysis confirms that the dam construction has caused the river flow to fluctuate significantly within the year. The dam construction has dramatically reduced the flow in April–May, a critical environmental and ecological season. The April–May period coincides with the river's flood season. The construction of the Voshmgir dam has caused the components of high flow in the environmental flow to face severe shortages.

Fungal infections are an evolving public health challenge due to their antimicrobial resistance and the growth of immunocompromised populations. Aquatic environments, the largest ecosystem on earth, are recently considered as a source for the production of bioactive compounds. Marine actinomycetes are considered for their potential to produce novel bioactive metabolites like antifungal compounds. In this study, strain ADR10 was obtained from the sediment sample of the Caspian Sea and its 16S rDNA gene sequence analysis suggested that the isolate belongs to Streptomyces albidoflavus. The preliminary cross-streak and double-layer agar screening revealed that the isolate has potent activity against pathogenic fungi, i.e. Aspergillus niger, Candida albicans, Fusarium oxysporum, and Penicillium crustosum. One-factor-at-a-time and Response surface methodology (RSM) was employed to evaluate the effects of six parameters (carbon source, initial pH, inoculation volume, NaCl concentration, nitrogen source, and temperature) on the production of antibiotics in the basal starch casein broth medium. The maximum antibiotic activity was achieved at the initial pH 7.05, sucrose 1.17 g l-1, malt 0.2 g l-1, temperature 30 ºC, inoculation size 5.0% v/v, and NaCl 1% w/v after 121.1 hours. Through the optimization experiments, antifungal activity was enhanced 2.7-fold. Ethyl acetate showed the highest antibiotic extraction capacity from the fermentation media compared with dichloromethane, hexane, and chloroform. The preliminary purified antibiotic by thin layer chromatography (ethyl acetate/ mobile petroleum phase) showed a more significant growth inhibition zone than nystatin (100 μg mL-1) against Candida albicans. This study underlines the potential of the marine actinomycete for the identification of novel antifungal agents.

Abstract Background The sturgeon group has been economically significant worldwide due to caviar production. Sturgeons consist of 27 species in the world. Mitogenome data could be used to infer genetic diversity and investigate the evolutionary history of sturgeons. A limited number of complete mitogenomes in this family were sequenced. Here, we annotated the mitochondrial Huso huso genome, which revealed new aspects of this species. Results In this species, the mitochondrial genome consisted of 13 genes encoding proteins, 22tRNA and 2rRNA, and two non-coding regions that followed other vertebrates. In addition, H. huso had a pseudo-tRNA-Glu between ND6 and Cytb and a 52-nucleotide tandem repeat with two replications in 12S rRNA. This duplication event is probably related to the slipped strand during replication, which could remain in the strand due to mispairing during replication. Furthermore, an 82 bp repeat sequence with three replications was observed in the D-loop control region, which is usually visible in different species. Regulatory elements were also seen in the control region of the mitochondrial genome, which included termination sequences and conserved regulatory blocks. Genomic compounds showed the highest conservation in rRNA and tRNA, while protein-encoded genes and nonencoded regions had the highest divergence. The mitochondrial genome was phylogenetically assayed using 12 protein-encoding genes. Conclusions In H. huso sequencing, we identified a distinct genome organization relative to other species that have never been reported. In recent years, along with the advancement in sequencing identified more genome rearrangements. However, it is an essential aspect of researching the evolution of the mitochondrial genome that needs to be recognized.

The article presents the results of comprehensive studies of the hydrological and chemical structure of the Middle and Northern Caspian Sea carried out aboard R/V Issledovatel Kaspiya in September 2022. It is shown, despite the continuing decrease in sea level, that there is no aeration of deep layers and a hydrogen sulfide layer persists with a tendency towards an increasing hydrogen sulfide concentration in the bottom layer. There is an enlargement in the oxygen minimum zone. The changes of the Caspian Sea ecosystem have led to weakening of nutrient transfer from the photic layer into the bottom layers and, as a consequence, to a decrease in the silicon concentration in the bottom layer. The results will make it possible to evaluate trends of ongoing changes. [ABSTRACT FROM AUTHOR]

The research aimed to assess the influence of atmospheric processes in the Northern Hemi-sphere’s Atlantic-European Sector on the Caspian Sea level based on the data for the days with Wangenheim-Girs atmospheric general circulation forms. The inputs covered the time period from 1900 to 2022. The information on the sea level, precipitation and ice events were harvested from 22 observation points in Kazakhstan and Russia. The statistical and comparative analysis as well as the climate change assessment within the framework of the study pointed to a stable correlation between the sea level and atmospheric circulation; re-vealed certain patterns reflected in precipitation distribution and frequency of moisture defi-cient and excessive years. The research also identified that the climatic changes have al-tered the sea’s ice regime, with the maximum ice thickness decreasing by 13-28 cm depend-ing on a specific water area. In addition to ice thickness variation, the recent decades show an increased frequency of moderate and mild winters, and the shift of the main glaciation dates, i.e. a stable ice cover forming later, the date of fixed maximum ice thickness observed in mid-February, the date of complete ice clearing observed in early-mid March, and the freezing period being shorter.

In this study, variations in the levels of oil hydrocarbons and polycyclic aromatic hydrocarbons (PAHs), which are persistent organic pollutants generated by human activities, were assessed in the bottom sediments of the Caspian Sea (Russia) sampled from 2012 to 2021. The samples were analyzed for their chemical composition. The concentrations of the identified compounds responsible for hydrocarbon pollution were established. The quantitative results of the industrial environmental monitoring in the Russian sector of the Caspian Sea for subsoil use were also reviewed and processed by standard statistical methods. It was revealed that ΣPAH concentrations in the Northern and Middle Caspian Sea regions vary from analytical zero to 186.7 µg/kg and from zero to 467.8 µg/kg, respectively. The scale of oil pollution in these two regions was found to be determined by the following PAHs: phenanthrene, acenaphthene, and naphthalene. The origin of the listed PAHs provides vital information on the main sources of pollution of the Caspian Sea bottom sediments with hazardous organic substances. Based on the obtained data, the areas with background PAH pollution of the bottom sediments and those with the characteristic PAH of mainly natural and pyrogenic origin were located.

The article presents the results of studies conducted on the analysis of risks in the underwater pipelines of the Azerbaijan sector of the Caspian Sea. For the study, the results of long-term observations of the state of the state of underwater pipelines and the opinions of experts in this field were collected. Based on the analysis of these data, the most characteristic situations were identified that, to one degree or another, led to the loss of pipeline performance and the need for repair and restoration work. It was found that the main hazards for subsea pipelines in the Caspian Sea are external and internal corrosion. Pipelines floating, damage at pipe junctions, vibrations, damage from falling foreign objects, and wave impacts in the coastal strip. For the listed main and other rarely observed situations, quantitative risk assessment was carried out using the Boston Cube method. The results of the assessment showed that the greatest risk is associated with external corrosion. [ABSTRACT FROM AUTHOR]

Hydrophysical studies in 2004–2018 showed that the cyclonic gyre of the Middle Caspian Sea is not a year-round circulation. In the cold season, the current in the cyclonic gyre intensifies, while in the warm season, the circulation weakens and the directed current turns into a drift one, except for the western part, where the water is transferred from the Middle Caspian to the southern part of the sea due to the difference in the levels of the basins. It is shown that the current in the cyclonic circulation follows the contour above the slope of the Derbent Basin in the entire layer from the surface to the bottom. The seasonal boundaries of the annual intensification and weakening of the cyclonic circulation are revealed. [ABSTRACT FROM AUTHOR]