bluuebunny/crossref_metadata_2025 huggingface dataset:
Cracking of Heavy Oil in Supercritical Water in the Presence of Iron Oxide Nanopowder: Asphaltene Transformations and Process Kinetics
Authors: Sviridenko N. N.
Published: April 2024

The products of catalytic cracking of heavy crude oil from the Ashalchinskoye oil field (the Almetyevsk district of the Republic of Tatarstan, Russia) were characterized. The effects of a Fe2O3 nanopowder catalyst and the presence of supercritical water (SCW) on the composition and structure of these cracking products were investigated. Cracking over 0.01 wt % Fe2O3 nanopowder in a SCW environment was found to enhance the yield of distillates by more than 34 wt % and to reduce the content of resinous asphaltene materials by a factor of 2.1 compared to the initial crude oil. It was further shown that Fe2O3-nanopowder-catalyzed cracking produces coke-like asphaltenes with a low H/C atomic ratio (no higher than 0.75). Reaction rate constants were evaluated for the thermal and catalytic cracking of the heavy oil from the Ashalchinskoye field.
The Hildebrand Solubility Parameter and Its Importance in the Scientific and Technological Scenario of Flow Assurance Operations
Authors: Zalamena Gabriela , Lopes Toni J. , Lucas Elizabete F. , Ramos Ant�nio C. S.
Published: April 2024

The Hildebrand solubility parameter has been applied in several areas of science and engineering, assuming a relevant role in new scientific developments and practical applications in industry. This review shows its importance and relationship with development of research in flow assurance activities, especially involving heavy fractions of oils such as asphaltenes, resins and wax. The examples described illustrate its relevance and scope in the approaches of interest of flow assurance. They also show that it is a versatile property for many new applications, including the development of methodologies to obtain more reliable values for the various petroleum fluids and theoretical developments for its estimation in a wide range of temperature and pressure.
Study of Rheological Characteristics of a Water-Based Drilling Fluid in Presence of Biopolymers, Synthetic Polymer, and Modified Natural Polymer
Authors: Shaine Mohammadali Lalji , Syed Imran Ali , Muhammad Arqam Khan
Published: April 2024

The major contemplation in the recent decades is to minimize the operational difficulties during any drilling activity by improving the characteristics of water-based drilling fluids (WBDF). Such problem as a poor hole-cleaning because of settling of drill cutting and debris are extremely common. This problem will eventually convert into a serious non-productive time event in the form of pipe sticking. The most common additives added in the mud system to improve its rheological properties and tackle sedimentation issues are polymeric materials. During this study, four different polymers including sodium alginate and pure-bore as biopolymers, PHPA as a synthetic polymer, and the L-grade polyanionic cellulose (PAC-L) as a modified natural polymer have been used to improve rheological characteristics of WBDF. Laboratory measurements have indicated no considerable changes in the mud weight in the case of addition of these polymers. Moreover, these results reveal that all the systems behave as shear thinning fluid (flow index 1). A decrease in the dynamic viscosity with an increase in the shear rate has been observed for all samples. The disentangling of polymeric chains occurring at high shear rate eventually reduces the viscosity of these systems. In addition, samples that comprised of pure-bore and sodium alginate exhibit the desired operating magnitude of rheology (PV, YP, GS, AV, and YP/PV). These results show such particles minimize operational problems arising because of a poor hole-cleaning. In contrast, a system with PHPA and PAC-L has shown detrimental rheological characteristics. The high molecular weight of PHPA and the hydration of PAC-L in the presence of potassium chloride decrease their performance.
Hydrogenation of Acetylene over Pd–Ag/Sibunit Catalysts: Effect of the Deposition Sequence of Active Component Precursors
Authors: Yurpalova D. V. , Afonasenko T. N. , Trenikhin M. V. , Leont'eva N. N. , Arbuzov A. B. , Temerev V. L. , Shlyapin D. A.
Published: April 2024

The study investigates interactions between palladium and silver in Pd–Ag bimetallic catalysts supported on a mesoporous carbon material Sibunit and, in particular, the dependence of these interactions on the deposition sequence of the metal precursors. Using XRD and TEM results, it was shown that impregnating the support with an aqueous solution that contained nitrate salts of both metals, followed by hydrogen treatment at 500°C, generates uniformly sized Pd0.6Ag0.4 particles (dav = 5.6 nm). These particles exhibit high selectivity (79%) in the reaction of acetylene hydrogenation to ethylene. The catalysts synthesized by sequential impregnation of the support with solutions of Pd and Ag nitrates interleaved with heat treatment in H2 exhibited a lower selectivity (68–73%) due to the formation of particles non-uniform both in composition and size (about 4 to 60 nm). The IR spectroscopy data suggest this effect is presumably associated with the removal of O-containing functional groups from the carbon surface during the reduction of the supported precursor. Given that O-groups act as anchoring sites for the precursors of active components and suppress the ability of Sibunit to reduce metals from their salt solutions, the subsequent deposition of the second metal salt causes a non-uniform distribution of this metal on the surface and the generation of larger particles.
Flameless Catalytic Combustion of Ethanol on Copper, Chromium, and Nickel Oxides
Authors: Arsent'ev S. D. , Grigoryan R. R. , Kocharyan G. G. , Stepanyan S. Kh. , Tavadyan L. A.
Published: April 2024

The possibility of using 3d-metal oxides as catalysts of self-sustaining catalytic flameless combustion of ethanol was examined. Monolithic catalysts CuO and Cr2O3, supported catalysts 25% CuO/SiO2 and 25% CuO/Al2O3, and ultrasonically treated catalyst 25% NiO/SiO2 can operate for a long time without changes in properties, ensuring 100% ethanol conversion. The wide range of the temperatures reached (300–590°C) allows choosing a catalyst meeting the process tasks.
Effects of the Tropical Climate of Vietnam on the Properties of Synthetic Greases with Urea Thickeners
Authors: Lyadov A. S. , Kochubeev A. A. , Kostina Yu. V. , Le An' Tuan , Fam Day Zyong
Published: April 2024

This study investigated, for the first time, the effects of the tropical climate of Vietnam on the properties of synthetic greases with urea thickeners. The greases were exposed to seven-month field tests at climatic test stations of the Joint Russian–Vietnamese Tropical Research and Technological Center in three regions of Vietnam. This short-term exposure decreased the ultimate strength and affected the colloidal stability of the samples (in the colloidal stability measurements, the amount of separated oil was reduced). At the same time, the chemical composition of the greases remained essentially unchanged, as confirmed by IR spectroscopy. It would be reasonable to assume that the degradation of polyurea greases in tropical climates is primarily associated with their colloidal structural changes. This assumption, however, requires confirmation in further research that should involve longer exposure and a larger number of grease samples prepared from different base oils. It was additionally found that introducing a heterogeneous modifier into polyurea greases impairs their stability in tropical climate.
Methane Pyrolysis in Molten Media for Hydrogen Production: A Review of Current Advances
Authors: Kudinov I. V. , Velikanova Yu. V. , Nenashev M. V. , Amirov T. F. , Pimenov A. A.
Published: April 2024

This review provides an analysis of prior research on liquid-media methane pyrolysis for hydrogen production. It discusses the experimental studies and reported data on methane pyrolysis in molten metals, molten binary alloys, molten salts, and molten metal–salt media. The experimental data suggest that binary metal alloys are superior to pure metals in terms of catalytic performance. A comparative assessment of catalytic activity showed that the highest performance (methane conversion above 95% at temperatures below 1200°C) has been achieved by molten Ni–Bi and Cu–Bi alloys. Besides the thermobaric conditions and characteristics of the bubbling systems, the media’s reactivity plays a key role in pyrolysis efficiency. The combined use of molten metals and salts as a reaction medium noticeably enhances the methane conversion (due to the catalytic activity of molten metals) and appreciably reduces the content of metal impurities in the carbon product.
Hydrodecyclization of Naphthenes over Iridium-Containing Zeolite Catalysts
Authors: Mamyan L. G. , Sadovnikov A. A. , Arapova O. V. , Maksimov A. L. , Naranov E. R.
Published: April 2024

The study investigates the hydrodecyclization of decalin over zeolite catalysts. The synthesized catalysts were characterized using a combination of physicochemical methods, such as TEM, SEM, low-temperature nitrogen adsorption/desorption, and XPS. The zeolite structure was found to have a major effect on the hydrodecyclization process. This process involves the isomerization of one ring followed by the opening of that ring. Incorporating iridium into the catalysts promoted the production of branched hydrocarbons. When testing the process in the temperature range of 300–400°C and at an initial hydrogen pressure of 50 atm, the Ir/BEA catalyst exhibited the highest activity: at 350°C the decyclization of decalin exceeded 50%.
Application of Coal Tar Products and Evaluation of the Stability of Residual Marine Fuels
Authors: Mingrui Liu , Zunzhao Li , Haibo Wang
Published: April 2024

Although the quality of coal tar does not meet the demands for blended marine fuel, the properties of its components after processing are improved, and they can be considered as inexpensive blending components. Three types of coal tar products including light coal tar I, light coal tar II, and hydrogenated coal tar have been obtained and used in production of residual marine fuels. To minimize costs, a linear optimization method has been used, and all properties of the resulting products have met the required criteria. In addition, a novel analytical method was used to characterize the fuel stability. The analysis of a hydrocarbon composition and a mechanism of interaction between the resin and asphaltene have shown the main coal tar components affecting fuel oil stability are polycyclic aromatic hydrocarbons (PAHs) and resin. A condensation of PAHs and resin into asphaltene and an increasing complexity of asphaltene structure causes deposition of oil products under heating. Hydrogenation is able to effectively reduce the PAH content and the volume of formation of massive asphaltenes thus preventing fuel flocculation and deposition during aging in fuel tanks.
Seasonal Variability of Calanus sp. Populations Size Structure in Svalbard Waters
Authors: Berchenko I. V. , Druzhkova E. I.
Published: April 2024

Based on the materials obtained in two fjords of West Spitsbergen Island, analysis of seasonal and spatial variability in the size distribution of Calanus sp. has been made. Statistically significant differences in the size structure of the fourth and fifth copepodite stages of the summer and late autumn period have been revealed. Populations of Grønfjorden and Billefjorden show spatial variability determined by local variations of the natural environmental factors. The discussed reasons of the observed seasonal variability are selective grazing of the largest specimens by predators of higher trophic levels, individual body size changes during accumulation or consumption of oil storage, as well as presence of two generations with different size parameters in the water column.
Effects of Mesoscale Stirring on Phytopigment Determinations in the Photic Water Layer from Multispectral Ocean Color Data (The Case of the Tasman Sea)
Authors: Karabashev G. S.
Published: April 2024

The inconstancy of phytopigment composition during intensive mesoscale mixing of the Tasman Sea photic layer was investigated using MODIS images of its surface. To do this, each pixel of such an image is assigned a WRM index equal to the sum of the wavelengths of the minima in the reflectance spectrum of the water surface within the boundaries of a pixel on the ground (Spectral Indexing of Pixels, or SIP approach). WRM is acceptable as an indicator of phytopigment composition variability in the water column, since the attenuation of light by water as a solvent and by its admixtures of other nature is inferior to light absorption by phytopigments in spectral selectivity, while the composition of phytopigments in the aquatic environment depends on the species composition of local phytoplankton. A co-analysis of WRM distributions and characteristics of Tasman Sea waters showed that with increased mesoscale variability in open ocean waters, phytopigment content in the near-surface layer reaches levels at which minimums of pigment origin at 400–550 nm, discernible by multispectral ocean color scanners, occur in the backscattered solar radiation spectrum. This phenomenon is ignored by common algorithms for chlorophyll determination based on the data of multispectral ocean color scanners (band-ratio algorithms) and, apparently, is one of the reasons for the known tendency of such algorithms to overestimate chlorophyll concentration relative to its real content in the water column. The conclusion is applicable to any ocean basins if they, like the Tasman Sea, are not affected by external sources of optically significant admixtures in water.
Possible Seismogenic-Trigger Mechanism of Activation of Glacier Destruction, Methane Emission and Climate Warming in Antarctica
Authors: Lobkovsky L. I. , Baranov A. A. , Vladimirova I. S. , Gabsatarov Y. V.
Published: April 2024

A seismogenic-trigger mechanism is proposed for the rapid activation of the destruction of cover and shelf glaciers in West Antarctica at the end of the 20th and the beginning of the 21st centuries, accompanied by the release of methane from the underlying hydrate-bearing sedimentary rocks and consequent rapid climate warming. This mechanism is associated with the action of deformation waves in the lithosphere-asthenosphere system, resulting from the strongest earthquakes occurring in the subduction zones surrounding Antarctica – Chile and Kermadec-Macquarie. Disturbances in the lithosphere are transmitted over long distances of the order of 3000 km, and the additional stresses associated with them, which come to Antarctica several decades after earthquakes, lead to a decrease in the adhesion of glaciers to underlying rocks, accelerated sliding of glaciers and the development of faults in them. This process, in turn, results in a reduction of pressure on the underlying sedimentary layers containing gas hydrates, which lead to methane emission and climate warming. The considered hypothesis leads to the conclusion that in the coming decades the processes of destruction of glaciers and climate warming in Antarctica will speed-up due to an unprecedented increase in the number of strongest earthquakes in the subduction zones of the South Pacific Ocean in the late 20th and early 21st centuries.
Modern and Relict Evidence of the Iceberg Scouring at the Bottom of the Barents and Kara Seas
Authors: Maznev S. V. , Kokin O. V. , Arkhipov V. V. , Baranskaya A. V.
Published: April 2024

The article systematizes and summarizes published data on the parameters and distribution areas of modern and relict iceberg scours (or plough marks), as well as on the maximum possible sizes and drift areas of modern icebergs in the Barents and Kara Seas. According to the open-source bathymetric data, for the first time the analysis of “throughput” of the waters in front of modern glaciers was carried out. Based on summarized and established facts, areas of the most likely distribution of modern iceberg effects on the bottom are determined by the method of expert assessment. This work is relevant both from a fundamental point of view and for determining the current depths limits of iceberg scouring at the bottom of the Barents and Kara Seas, which is important for ensuring the geoecological safety of all kinds of activities on the sea shelf.
About a Possible Frontogenetic Role of Salt Finger Type Convection in the Ocean
Authors: Pereskokov A. I.
Published: April 2024

The fundamental problem of the study of oceanic fronts is to find the mechanisms that play an essential role in the generation of fronts (frontogenesis) of planetary scale and to maintain them. To study this problem with regard to the North Atlantic Ocean the fields of horizontal temperature (and salinity) gradients in the intermediate water column have been compared for the first time to the field of density ratio that characterizes the spatial inhomogeneity of vertical heat and mass transfer due to the processes of double diffusion of heat and salt. The comparison shows the presence of more or less sharp thermohaline frontal zones throughout the periphery of the two vast areas in the subtropical and tropical zones covered by intense differential-diffusion convection in the salt finger regime. This is a strong argument for the fact that this previously ignored small-scale (experiencing impact of molecular processes) convection may be a prime cause of large-scale frontogenesis in the oceanic water column.
Impact of the Atlantic Meridional Overturning Circulation on Upper Water Temperature of the North Atlantic and the Atlantic Sector of the Arctic Ocean
Authors: Iakovleva D. A. , Bashmachnikov I. L. , Kuznetsova D. A.
Published: April 2024

In this study we investigate the impact of variability of the Atlantic Meridional Overturning Circulation (AMOC) on water temperature of the upper 100-m layer of the North Atlantic and Arctic oceans. We use three data-sets (ARMOR-3D, SODA3.4.2 и ORAS4) with different spatial resolution and covering different time periods. The temperature variability is decomposed into its natural modes using Empirical Orthogonal Functions (EOF). The second EOF, which accounts for 20–27% of dispersion of water temperature in the upper ocean, is associated with a change in the AMOC intensity. The time variability of the principal component of this mode has high correlation with the AMOC (0.6–0.9 depending on the data-set and the AMOC index used). The AMOC has the highest impact on water temperature in the Irminger and Labrador seas. The related amplitude of water temperature fluctuations reaches 1.5–2°С in the central part of the Irminger Sea, which is one of the key deep convection regions. Intensification of the AMOC leads to an increase the upper ocean temperature over most of the North Atlantic and Norwegian Sea and to a decrease of water temperature over most of the Greenland Sea, Barents Sea and in an area north of Spitsbergen.
Bioindication of Bottom Sediments of the Gulf of Finland by the Composition of Meiobenthos in Combination with Biotesting and Chemical Analysis
Authors: Berezina N. A. , Petukhov V. A.
Published: April 2024

The question of the possibility of using meiobenthos to monitor the state of bottom sediments (BS) in the Baltic Sea, where bottom macrofauna are unstable due to hypoxia, is of interest. The parameters of meiobenthos and the physicochemical characteristics of BS and bottom water were studied, and the toxicity of BS was determined by the survival of the amphipod Gmelinoides fasciatus in 10-day tests for 11 stations in the brackish part of the Gulf of Finland (depths of 10–52 m). Principal component analysis revealed two factors explaining 67% of the variability of the variables, and groups of stations similar in terms of conditions. Factor 1 combined nine related variables (depth, metal concentrations and fraction of sand in BS, ratio of nematodes and copepods (N/C index) and survival of amphipods), and factor 2 combined four variables (organic matter and polyaromatic hydrocarbons in BS, phosphates in water and the number of meiobenthos). Thus, bioindication of the environment by meiobenthos is promising, but requires an integrated approach to be applied in monitoring.
On the Mechanisms Generating the Nearshore Bars on a Sandy Coastal Slope
Authors: Leont’yev I. O.
Published: April 2024

The study is aimed at investigation of the problem in what conditions the morphodynamic self-organizational mechanism controlling the growth of small perturbations arisen on bed could be responsible for the nearshore bars development. A simplified sediment transport model is used in which the sediment discharge is turned out directly proportional to the local bed slope. This model allows reducing the problem to an analytical solving of the diffusion equation which gives the base to predict the evolution of perturbation arisen on bed. The conclusion is argued that the favorable preconditions for the nearshore bar formation can exist in the case of onshore sediment transport associated with the dominating contribution of wave asymmetry in transport process. However under conditions of steep stormy waves the undertow is developed providing offshore sediment flux from the beach. In this case, the breaker bar is formed by two mechanisms–self-organization and convergence of opposite sediment fluxes. The results obtained are in agreement with available data and also assist to explain some properties of multiple-bar systems found out from observations.
Verification of the Daily Periodicity of Microincrements Formation on the Otoliths of the Juvenilrs of the Ocellated Blenny Opisthocentrus ocellatus (Stichaeidae) for a Retrospective Evaluation of the Period of Mass Hatching under the Conditions of Peter the Great Bay of the Japan Sea
Authors: Shelekhov V. A.
Published: April 2024

Experiments were carried out on intravital otolith-tagging of juveniles of the ocellated blenny after transition to benthic life mode with Alizarin Red S. Marking at a dye concentration of 200 mg/L for 16–18 h at night, gave 100% formation of fluorescent marks with zero mortality of experimental individuals. Alizarin marks on the otoliths correspond to “stress” marks in the form of darker micro-increments, visible in transmitted light. The calculation of microincrements in the zone between two consecutive markings with an interval of 9 days confirmed the daily periodicity of their laying at this stage of development of the ocellated blenny. This allowed us to determine the period of hatching in natural conditions of juveniles in the Zhitkov Bay (Russky Island, the Peter the Great Bay, Japan sea). Hatching of larvae in 2017 in this species occurred, according to our estimates, from the last decade of March to the end of the second decade of April, with a peak in the first decade of April. Hatching begins even under the ice at a slightly negative water temperature of –1–0°C, but it proceeds mainly already at a temperature of 1–3°C, after the removal of ice from the bay. Taking into account the known timing of spawning of the ocellated blenny in the Peter the Great Bay (November–early December), we can state that the development of its eggs in this area is greatly slowed down at water temperatures below zero in December–March and can go on for 4–5 months, which is almost 3 times longer than the development time in more mild conditions of the south Hokkaido.
Complexes of Marginal Sea Paleobasins of the Olyutorka–Kamchatka Region (Structure, Composition and Geodynamics)
Authors: Tsukanov N. V. , Fedorov P. I.
Published: April 2024

The structural features of the Olyutorsko-Kamchatka accretion region allow us to reconstruct two paleobasins for the Late Cretaceous-Paleogene time, separated and fenced off from the ocean by volcanic arcs. The features of the structure and composition of the complexes characterizing the fragments of the oceanic crust show that these basins had a different nature. The age of the fragments of the crust of the Lesnovsko-Iruneisky basin are Alb–Maastrichtian.Volcanites are represented by differentiated toleites of the N-MORB type, rarely intraplate basalts and enriched toleites of E-MORB. Fragments of the crust of the Vetlovsky basin are of age from the Campan–Maastrichtian to the Middle Eocene. Among the volcanites, basalts of N‑MORB are mainly developed, less often E-MORB and, in some structures, basalts of oceanic islands (OIB). Geodynamics in the Late Cretaceous–Cenozoic time for the Kamchatka and Olyutorsky segments differed, starting from the Campanian time.
Structure and Spatial Distribution of Mesozooplankton Communities in the Atlantic Sector of the Southern Ocean
Authors: Kasyan V. V.
Published: April 2024

In this paper, the composition and patterns of spatial distribution of mesozooplankton communities in the waters of the Bransfield Strait, the Antarctic Sound, the Powell Basin of the Weddell Sea and the waters off the Antarctic Peninsula and South Orkney Islands during the austral summer of 2022 are presented. Among the mesozooplankton communities two groups were found to be the most abundant: copepods Calanoides acutus, Metridia gerlachei and Oithona spp., and euphausiids Euphausia superba. The maximum abundance and biomass of the mesozooplankton were found in the warm Antarctic surface deep-sea water off the South Orkney Islands. The minimum values, respectively, were found in the cold modified Weddell Sea waters off the Antarctic Peninsula. Copepods was concentrated in the Bransfield Strait near the South Shetland Islands with sea surface temperature (SST) of –0.5–0.5°С and sea surface salinity (SSS) of 34.5–34.6‰; and the krill E. superba eggs and larvae at different development stages was concentrated in the waters off the South Orkney Islands with SST values of 1–2°С and SSS values of 34.3–34.5‰. Four groups of mesozooplankton communities at different composition, abundance, and taxa dominance were identified. The results of this and future study have practical implications for monitoring the state of the changing ecosystem of the Southern Ocean.
Primary and Bacterial Production in the Bransfield Strait (Antarctica) in Summer
Authors: Mosharov S. A. , Mosharova I. V. , Frey D. I. , Seliverstova A. M. , Latushkin A. A. , Gontarev S. V.
Published: April 2024

The spatial distribution of the main primary productivity parameters in the Bransfield Strait in the Antarctic summer presents. The integrated primary production in the strait varied from 435 to 741 mgC/m2 per day. The share of primary production in the total production of phyto- and bacterioplankton in the upper 10th layer was 82–91%. Potential photosynthetic capacity (Fv/Fm) was high within the euphotic layer (0.418–0.749) throughout the area. The production parameters in the two main water masses in the strait did not differ. Photosynthetic efficiency (the ratio of the assimilation number and the relative electron transport rate, AN/rETR) varied in different subregions of the study area by almost six times.
Agent-Based Model of Diatom Population Dynamics in Marginal Arctic Seas in Summer
Authors: Fursova P. V. , Riznichenko G. Yu. , Konyukhov I. V. , Pogosyan S. I.
Published: April 2024

A hypothesis is proposed for the functioning of the diatom population under conditions of water column stratification. It is assumed that cells in the upper illuminated water layer accumulate biomass due to photosynthesis. In the lower layer, rich in minerals, the cells replenish their intracellular reserves. Moving from one layer to another allows to cells to compensate for the lack of resources. Sinking occurs as a result of sedimentation, and lifting occurs due to the release of carbon dioxide microbubbles in the process of respiration. On the basis of this hypothesis, an agent model of the population is constructed. The calculations have shown that vertical movements ensure the existence of the population. Various surface illumination make it possible to obtain various distributions of cell numbers in the upper and lower water layers, which is consistent with the data of expeditionary observations.
Mesoscale Anticyclonic Eddies in the Primorye Current System of the Japan/East Sea in the Summer
Authors: Ostrovskii A. G. , Kubryakov A. A. , Shvoev D. A. , Kaplunenko D. D.
Published: April 2024

This study identified a process of water supply due to discrete transport by anticyclonic eddies towards the formation region of the intermediate water in the northwestern Japan Sea in the summer season. The structures and dynamics of three anticyclonic mesoscale eddies were studied by means of the Aqualog moored profiler observational survey at the continental slope in the Primorsky Current region east of Peter the Great Bay in June–July 2015. It was shown that the eddy cores were of ellipsoidal shape with an elongated lower part. The anticyclones as isolated dynamic structures carried water enriched with dissolved oxygen in the west-southwest direction. In terms of the thermohaline characteristics the water transported was similar to the Japan Sea intermediate water at its formation region south of Peter the Great Bay.
Recent Benthic Foraminiferal Assemblages in the Western Part of the East Siberian Sea
Authors: Ovsepyan E. A. , Ovsepyan Ya. S. , Zenina М. А. , Mitrofanova N. О.
Published: April 2024

Benthic foraminiferal assemblages were studied in twenty surface sediment samples collected in the western part of the East Siberian Sea in the framework of the expedition of the R/V “Ivan Kireev” in 2004. Rose Bengal treatment allows us to separate “living” and “dead” individuals. Taxonomic analyses reveal that “living” calcareous foraminifers dominate in the study region with the exception of the New Siberian Islands area and area to the northeast from the Indigirka river mouth where agglutinated tests constitute up to a half of the assemblage. Little amount of dead individuals points to a rapid dissolution of calcareous tests immediately after death of organism. Taxonomic composition of the studied assemblages is similar to river-proximal benthic foraminiferal assemblage previously determined for the Kara Sea. In the East Siberian Sea, the most commonly occurred species are E-lphidium clavatum, Elphidiella groenlandica, Haynesina orbiculare, E. incertum и Lagenammina atlantica. Less abundant species are Gordiospira arctica, Buccella frigida, E. bartletti, Reophax curtus, R. scorpiurus and polymorphinids. As a result of statistical treatment, four areas with specific BF assemblages have been distinguished: area of the Indigirka River mouth, zone affected by Siberian Coastal Current, area located to the north of the Siberian Coastal Current and zone situated close to the New Siberian Island archipelago together with an area located to the northeast from the Indigirka river mouth. Such a distribution of BF assemblages in the study area seems to be related to the distance of the river discharge area, type of sediments and fresh organic matter content.
Expeditional Studies in the Baltic Sea in Cruise 54th of the R/V “Akademik Sergei Vavilov”
Authors: Dorokhov D. V. , Sivkov V. V. , Mosharov S. A. , Semenov P. B. , Ezhova E. E. , Kondrashov A. A. , Bubnova E. S. , Ponomarenko E. P. , Gerb M. A.
Published: April 2024

Brief results of oceanological studies of the southeastern part of the Baltic Sea and the Gulf of Finland during 54th cruise of the R/V Akademik Sergei Vavilov (2022) are presented. Hydrology, hydro- and geochemistry, hydrobiology, geoecology, geology and geophysics investigations were carried out. New data on the state and dynamics of the natural complexes of the Baltic Sea under the conditions of increasing anthropogenic pressure and climate change were obtained.
Сhanges of Thermal Conditions Trends in the Tropical Zone of the Pacific Ocean in 1982–2021
Authors: Rostov I. D. , Dmitrieva E. V. , Rudykh N. I.
Published: April 2024

Based on National Oceanic and Atmospheric Administration (NOAA, USA) and Japan Meteorological Agency (JMA) climate data sets for 1982–2021, regional features and trends of interannual changes of water temperature in the upper 2200-m layer of the Pacific Ocean tropical part were investigated, as well as their possible relationships with variations of climatic characteristics. Obtained results provide description of three-dimensional structure of the temperature anomalies and heat content variability in the water column and rate of warming in the various areas for specific phases of the resent global warming.
Internal Waves Generated by the Inflow of the Kodor River in the Black Sea
Authors: Serebryany A. N. , Khimchenko E. E. , Goncharov V. V. , Tarasov L. L. , Popov O. E. , Belov D. V. , Neshenko I. P.
Published: April 2024

The results of studies of internal waves in the shelf zone of the Black Sea in the water area near the mouth of the Kodor River, conducted in June 2021, are presented. Spatial surveys were carried out with ADCP “Rio Grande 600 kHz”, which revealed the main characteristics of currents and the presence of internal waves generated by the river inflow in to the sea. Internal waves were recorded in two sections oriented along the normal to the coastline and extending to depths of 100 m. The observed waves had the features of nonlinear waves, were located on the near-surface thermocline, and had a height of up to 3–6 m. Also short-period internal waves in the form of a train of waves with an apparent period of about 3.5 min were recorded by a chain of thermistors in the coastal zone of the sea. The dispersion curves and eigenfunctions of internal waves were calculated by numerically solving the equation of internal waves, taking into account the velocity shift in the sea. Theoretical data are compared with experimental ones. A significant influence of the river inflow on the parameters of the generated internal waves moving with the flow was revealed. The experimentally observed decrease in wave periods and an increase in their group and phase velocities were confirmed.
Numerical Modeling of Tidal Phenomena of the Penzhinskaya Bay
Authors: Shpachuk D. R. , Sokolov O. V. , Bugaets A. N.
Published: April 2024

In this study, the Delft3D-Flow hydrodynamic model was used to determine the characteristics of the main tidal waves and currents in the Penzhina Bay (Sea of Okhotsk, Russia). The initial and boundary conditions are set according to the TPXO9 model data, the salinity and water temperature for each model layer are set based on the reanalysis data of the HYCOM ocean general circulation model, with a time step of 3 h. E-uropean Center for Medium-Range Weather Forecasts ECMWF (European Center for Medium-Range Weather Forecasts) reanalysis ERA-5 was used as meteoforcing. Modeling was performed for the ice-free period from May to September 2005. Maps of cotidal lines, tidal ellipses, and reversibility coefficient for the main tide waves: semidiurnal wave M2 and diurnal wave K1 were constructed. The model was verified by comparing the published and calculated harmonic components for 9 sea level monitoring points located in the Penzhina Bay. Conformance evaluation generally shows a high degree of consistency between model and reference data. The values of the coefficient of determination R2 between the series formed by the model and published harmonic components are in the range of 0.96–0.99. According to the magnitude of relative errors, the simulation results are divided into two consistency categories – high (1.48–2.14%) and satisfactory (2.93–4.27%). Spatial patterns of distribution for the values of relative errors were not found. A certain inconsistency in the results is presumably due to the time discretization of the observation time support and the short sea level monitoring data series used to calculate the published harmonic components at the Penzhina Bay.
A new species of horse mackerel fish of the genus Archaeus (Carangidae, Percomorpha) from the Lower Oligocene of the North Caucasus
Authors: Bannikov A. F. , Erebakan I. G.
Published: April 2024

A new species of horse mackerel fish (Carangidae), Archaeus solus sp. nov., was described based on the imprint of a complete skeleton from the Lower Oligocene (Pshekha Formation) of Gorny Luch locality. This is the third known species of the Eocene–Oligocene genus Archaeus Agassiz, 1844, and the first discovery of Carangidae in the Oligocene of the North Caucasus. The new species differs from A. glarisianus Agassiz, 1844 from the Rupelian of Switzerland and A. oblongus Daniltshenko, 1968 from the basal Eocene of Turkmenistan by a larger number of rays in both the spiny and soft dorsal fin.
Miocene Hydrobiidae (Gastropoda) of the Eastern Paratethys
Authors: Guzhov A. V.
Published: April 2024

A review of the family Hydrobiidae from the Tarkhanian and Chokrakian deposits was made. New genus Islamiella was described, in which the species I. miocenica sp. nov. (upper Tarkhanian–lower Chokrakian) and I. maeotica sp. nov. (lower Maeotian) were included. Last species is widely distributed in the facies, concomitant with the bryozoan buildings of the Maeotian beginning. Peringia tarkhanica sp. nov. was described fom the Tarkhanian, whereas Hydrobia kubanica Zhizhchenko, 1936 was redescribed from the Chokrakian. Several species descibed earlier as Hydrobia by Zhizhchenko were synonymized with the species from the other families: H. subprotracta Zhizhchenko, 1936 icluded in synonymy of Finella andrusovi andrusovi (Bajarunas, 1910), and H. stavropoliana Zhizhchenko, 1936 reffered to the genus Odostomia, most probably to species O. nuda Bajarunas, 1910.
The First Record of a Species of the Genus Acicnemis Fairmaire (Coleoptera: Curculionidae) in Miocene Sumatran Amber
Authors: Legalov A. A.
Published: April 2024

A new species of the genus Acicnemis Fairmaire, 1849 is described from the early Miocene Sumatran amber. The new species, Acicnemis sumatranus sp. nov., differs from A. suturalis Roelofs, 1875 in the larger body size, a small antennal club, longer femora, and a large teeth on the metafemora. This is the first record of the tribe Acicnemidini in the Neogene and the first described beetle from Sumatran amber.
Problematical Porifera from the Lower Cambrian of Western Mongolia
Authors: Luzhnaya E. A. , Zhegallo E. A. , Zaitseva L. V. , Ragozina A. L.
Published: April 2024

From the lower part of the Tommotian Stage of the Lower Cambrian of Western Mongolia, ridge Hevte-Tsakhir-Nuruu described a new species of problematical microfossils of the genus Aetholicopalla Conway Morris in Bengtson et al., 1990, whose representatives are sometimes the dominants of the Early Cambrian taphocoenoses. A. grandipora sp. nov. – spheroidal organisms with initially carbonate (?) skeleton; planktonic and benthic forms described; the latter have a variable shape and attachment sites to the bottom substrate. The outer wall of the fossils is perforated, thin, double; the functional implication of the holes is unclear; be present an internal cavity. By mode of existence, these organisms were probably filter feeders. Geochemical analysis of various taphomorphs showed that A. grandipora sp. nov. preserved by phosphate and siliceous mineralization in the early stages of fossilization. The set of recognized characters allows us to attribute Aetholicopalla to the first skeletal Porifera of an unclear taxonomic position; perhaps these were juvenile forms of organisms close to archaeocyates.
New Radiolarian Species from the Lower Carboniferous of the Volga–Ural Basin and the Upper Carboniferous of the South Urals of Russia
Authors: Afanasieva M. S.
Published: April 2024

The genus Triaenosphaera Deflandre, 1973 is revised and its diagnosis is emended. Four new radiolarian species from the Lower Tournaisian (Mississippian) of the Volga–Ural Basin and the Upper Kasimovian (Pennsylvanian) of the South Urals are described: Entactinia zaitsevae sp. nov., Triaenosphaera fortunatovae sp. nov., T. spiroacus sp. nov. and Spongentactinia oraia sp. nov.
New and Little Known Permosialidae (Insecta: Palaeomanteida) from Upper Permian of Mongolia and Middle or Upper Triassic of Kyrgyzstan
Authors: Aristov D. S. , Rasnitsyn A. P.
Published: April 2024

Composition of the family Permosialidae (Insecta: Palaeomanteida) is revised in the Upper Permian deposits of Mongolia and Kazakhstan. In Wuchiapingian insect site Bor-Tologoy in South Gobi Aimag, Mongolia, Permosialis postuma sp. nov. and P. virgata sp. nov. are described and P. mongolica (Storozhenko, 1992) comb. nov. (=Tologoptera mongolica Storozhenko, 1992) and Palaeomantopsis nana (Storozhenko, 1992) comb. nov. (=Tologoptera nana Storozhenko, 1992) are redescribed. In Changhsingian locality Karaungir in East Kazakhstan Region of Kazakhstan Permosialis frivolus (Storozhenko, 1991) is redescribed. In Ladinial or Carnian Lagerstätte Dzhayloucho (Madygen) in Kyrgyzstan P. triassica Novokshonov et Zhuzhgova is redescribed. New synonymy is established: Permosialis asiatica Martynova, 1961 =P. sibirica Martynova, 1961, syn. nov.
The Most Ancient Representatives of the Genus Pinna (Bivalvia) in the Early Permian Reef of Shakhtau (Southern Cis-Urals, Russia)
Authors: Shilekhin L. E. , Mazaev A. V. , Biakov A. S.
Published: April 2024

A new and most ancient species of the genus Pinna, P. pacata sp. nov., has been described from the Lower Permian deposits of the Shakhtau reef (southern Urals, Russia). Until now, the most ancient finds of representatives of this genus were known from the Lower Triassic. The new species adds to the list of species ancestral to Mesozoic forms, which makes it possible to consider the Ural Strait as one of the centers of Late Paleozoic mollusk diversification.
On the Evolution of Some Groups of Marine Bony Fishes in the Cenozoic of the Tethys and Paratethys
Authors: Bannikov A. F. , Erebakan I. G.
Published: April 2024

Data on the principal Cenozoic localities of marine bony fishes (represented by skeletal remains, not otoliths) from the territory of the development of the Tethys and Paratethys are presented. The historical development of many supra-generic taxa of the higher Teleostei (spiny-rayed) in the Cenozoic basins of the Tethys and Paratethys has been traced. The available paleontological data do not confirm the appearance of most lineages of “crown Acanthomorpha” (and even “crown Percomorpha”) already at the end of the Cretaceous, as indicated by the time-calibrated molecular phylogeny.
New Givetian Conodonts of the Genus Icriodus from the Kolyvan-Tom Folded Area (South of West Siberia)
Authors: Izokh N. G.
Published: April 2024

New species Icriodus alchedatensis sp. nov., I. kuzbassiensis sp. nov. I. lebedyankensis sp. nov. and Latericriodus sp. E are described from stratotype sections of the Mazalovy Kitatian regional Substage of the Middle Givetian from the Kolyvan-Tom folded area. The taxa of the genus Icriodus belong to two phylolines of the genus Icriodus: the I. struvei phylolines and the I. regularicrescens phylolines according to the concept of Weddige (1977).
First Evidence of Damage by Micromycetes on Infructescences of Cretaceous Genus Friisicarpus N. Maslova et Herman (Platanaceae)
Authors: Maslova N. P. , Tekleva M. V. , Blagoveshсhenskaya E. Yu.
Published: April 2024

Morphologically similar damage of carpels of two Friisicarpus species (Platanaceae), F. kubaensis (Western Siberia, Albian–Cenomanian) and F. sarbaensis (Western Kazakhstan, Cenomanian–Turonian) induced by micromycetes have been described for the first time. Fruiting bodies of the micromycetes are developed within the tissues, forming tubercles on the carpel surfaces. Morphology of the fruiting bodies, their distribution on the substrate, as well as dropping out of the substrate after maturation bring them together with some modern representatives of Pleosporales. A possible role of insects in the transferring of fungal spores and participation of arthropods in the pollination of early Platanaceae are discussed.
Small Ducks (Aves: Anatidae) from the Early–Middle Miocene of Eurasia. 3. A Revision of Mionetta natator (Milne-Edwards, 1867)
Authors: Zelenkov N. V.
Published: April 2024

The results of a taxonomic and morphological revision of Mionetta natator (Milne-Edwards, 1867) from the lower Miocene of Western and Central Europe are presented. It is shown that the collections of small ducks from Saint-Gérand-le-Puy localities (France) indeed contain a small species of the genus Mionetta, which is here described as Mionetta defossa sp. nov. At the same time, Mionetta natator represents a separate taxon and is here assigned to the genus Caerulonettion gen. nov., showing morphological similarities with modern Malacorhynchus and fossil Mioquerquedula spp. The first finds of small ducks from the lower Miocene of Kazakhstan are also described (Aral Svita, the Agyspe and Altynshokysu localities; Akzhar Svita, the Blue Sands locality), tentatively attributed to Mionetta defossa and Mionetta sp. The diversity and relationships of small ducks of the early–middle Miocene of Eurasia are discussed.
Assessment of the effect of contemporary climate warming on the small ground squirrel fleas population dynamics in Northwestern region of Caspian Depression
Authors: Magerramov S. V , Martsokha K. S , Mandzhieva V. S , Smolyankina M. G , Grigoriev M. P , Kuznetsov A. A , Popov N. V
Published: April 2024

The dominant zonal rodent species in the steppes and semi-deserts of the Caspian Lowland is the small ground squirrel Spermophilus pygmaeus (Pallas, 1778). Flea species, which are its specific ectoparasites, play a significant role in the occurrence of plague epizootics in this area. The impact of global climate warming on the population dynamics of the fleas of the small ground squirrel in the northern deserts on the territory of the Caspian Lowland is discussed in this article. The literature sources and extensive archival materials were used for the analysis. The Ilmen-Pridelta landscape region (southwest of the Astrakhan Region), which is most fully characterized through the necessary quantitative indicators, was chosen as a model territory. The data of the annual spring-summer registration of indices of the flea abundance in wool and at the entrances of the burrows of the small ground squirrel, as well as his abundance rates (number of specimens per 1 ha), average monthly air temperature values reported by meteorological stations in Astrakhan over the past 70 years were statistically processed. The article reveals the mechanism of the influence of contemporary climate warming on the dynamics of the number of fleas of the small ground squirrel in the territory of the Caspian Lowland over the period of 1950-2021.
Arthropod-borne and arthropod-related viruses in Iran and neighboring countries
Authors: Azari-hamidian S. , Harbach R. E.
Published: April 2024

Arthropods are very significant for human and veterinary medicine and health because of the burden of diseases caused by the pathogens they transmit. Databases, including the Web of Science, PubMed, Scopus, Google Scholar, CABI, Scientific Information Database, IranMedex and Magiran were searched to the end of December 2022 for publications concerning infections in Iran caused by arboviruses. Pertinent information was extracted and analyzed. Thirty-three viral infections occur in Iran, which are biologically or mechanically known or assumed to be transmitted by arthropods. Information about agents (viruses), distribution (in 31 Iranian provinces), hosts (human and animals) and known vectors in Iran was obtained for each disease. Also, a list of arboviruses was provided for the countries neighboring Iran, including Afghanistan, Armenia, Azerbaijan, Bahrain, Iraq, Kuwait, Oman, Pakistan, Qatar, Saudi Arabia, Turkey, Turkmenistan and the United Arab Emirates, as well as Djibouti, Somalia, Sudan, Syria and Yemen, which do not neighbor Iran but, like Iran, occur in the World Health Organization Eastern Mediterranean Region. This list includes 40 viruses which are not formally recorded in Iran. The viruses are members of 19 genera representing 14 families in which three, four, 20 and 29 viruses are sandfly-borne, biting midge-borne, mosquito-borne and tick-borne, respectively.