Alexander Izhitskiy

Shirshov Institute оf Oceanology, Russian Academy of Sciences

Latest data on the hydrophysical and biological state of the residual basins of the Aral Sea are presented and compared. Direct, quasi-simultaneous observations were carried out in the central part of the Western Large Aral Sea, the northern extremity of the Large Aral known as Chernyshev Bay, Lake Tshchebas, and the Small Aral Sea in October 2014....

Due to catastrophic desiccation, today’s Aral Sea consists of a few separate residual basins, characterized by different ecological conditions (the Large Aral, Lake Tshchebas, the Small Aral). This study is the first report on dissolved methane concentrations in these basins. Overall, 48 water samples were obtained and analyzed for methane content....

The Aral Sea desiccation is one of the worst aquatic ecological disasters of the last century, important for understanding the worldwide trends to degradation of arid lakes under water use and climate change. Formerly the fourth largest lake worldwide, the Aral Sea has lost ∼90% of its water since the early 1960s due to irrigation in its drainage b...

Inland waters in the endorheic basins of the arid zone are especially vulnerable to both climate-induced changes and anthropogenic influence. The North Aral Sea, which previously suffered a drastic shrinkage and partially recovered with the launch of the human-made Kokaral dam, is currently subject to significant inter-annual variability of its wat...

Based on data of the three-channel hyperspectrometer designed for remote passive optical observations from a moving vessel at a frequency of 1 Hz, a distribution of areas of increased turbidity in the Kerch Strait was obtained. Comparison of these results with the analysis of temperature, salinity, and direction of water flow in depth measured at t...

The paper presents the results of an analysis of the main pollutants (heavy metals, pesticides, detergents, hydrocarbons) in water, suspended particulate matter, and bottom sediments, as well as the hydrophysical fields in the Kerch Strait and adjacent Black Sea water area (2019–2020 ). In all seasons, the concentrations exceeded the maximum permis...

As the largest methane reservoir in the world, the Black Sea is characterized by significant variability in its dissolved methane distribution patterns. Aerobic waters in the coastal regions are influenced by various factors governing the biogeochemical processes in the water column; however, their impact on the distribution pattern of dissolved me...

New hydrochemical data from the residual waterbodies of the Aral Sea situated in Kazakhstan (Small Aral Sea, Chernyshev Gulf, and the newly separate former Tshchebas Gulf) were collected in field surveys of 2015, 2016, 2018 and 2019. Comparison of the recently obtained data with historical records points to the continuing evolution of the salt comp...

Purpose. The work is aimed at assessing the effect of variations in the major ion-salt composition on the accuracy of determining water salinity in the inland seas and other seawater areas. The main goal of the study is to assess the representativeness of the results of the CTD salinity measurements (standard in oceanological practice) for the area...

During the last few decades, the rapid separation of the Small Aral Sea from the isolated basin has changed its hydrological and ecological conditions tremendously. In the present study, we developed and validated the hybrid model for the Syr Darya River basin based on a combination of state-of-the-art hydrological and machine learning models. Clim...

Field measurements carried out over 4 years made it possible to establish previously unknown features of the thermohaline fields and circulation of Lake Issyk-Kul. The most detailed salinity distribution maps for the entire history of observations were constructed. An area of slightly increased salinity was found in the central part of the lake, th...

During the last few decades, the rapid separation of the Small Aral Sea from the isolated basin has changed its hydrological and ecological conditions tremendously. In the present study, we developed and validated the hybrid model for the Syr Darya River basin based on a combination of state-of-the-art hydrological and machine learning models. Clim...

Authigenic biominerals and their associations with minerals of other origin are used as indicators of the geological, hydrological, and ecological characteristics of ancient and modern aquatic geosystems. Extreme environments of biomineralization lead to the appearance of specific structural and chemical features of minerals that must be considered...

This article reports the results of three field campaigns conducted in Lake Issyk-Kul in 2015, 2016, and 2017. During the campaigns, CTD profiling and water sampling were performed at 34 locations all over the lake. A total of 75 CTD profiles were obtained. Some biogeochemical and thermohaline parameters at the lake surface were also mapped at high...

This article reports the results of 3 field campaigns conducted in Lake Issyk-Kul in 2015, 2016, and 2017. Vertical CTD profiles were obtained and water samples collected at the total of 75 stations. Some biogeochemical and thermohaline parameters at the lake surface were also mapped at high horizontal resolution along the ship’s track. In addition...

The Aral Sea desiccation and related changes in hydroclimatic conditions on a regional level is a hot topic for past decades. The key problem of scientific research projects devoted to an investigation of modern Aral Sea basin hydrological regime is its discontinuous nature – the only limited amount of papers takes into account the complex runoff f...

This paper was initially motivated by an observational case study conducted in May 2015 on the shelf of the Crimea Peninsula, just west of the Kerch Strait, through which the Black Sea receives the inflow of lower salinity, higher turbidity water from the Sea of Azov. The latter often propagates westward along the coast, creating two-layered vertic...

We report results of a field survey conducted in the buoyant, sediment-carrying coastal plume generated by the discharge from the Patos Lagoon, the World's largest choked lagoon. The concentration of total suspended matter (TSM) and organic matter (as represented by total organic carbon, TOC) were mapped using an ultraviolet fluorescent LiDAR, whic...

The paper presents original authors' data on the O, H, C, S, and Sr isotopic composition of water and sediments from the basins into which the Aral Sea split after its catastrophic shoaling: Chernyshev Bay (CB), the basin of the Great Aral in the north, Lake Tshchebas (LT), and Minor Sea (MS). The data indicate that the δ¹⁸О, δD, δ¹³C, and δ³⁴S of...

Studying of methane formation and distribution in natural waters is important for understanding of biogeochemical processes of carbon cycle, searching for oil and gas sections and evaluation of CH4 emissions for investigations of greenhouse effect. The Black Sea is the largest methane water body on our planet. However, relatively low values of meth...

This article presents a new method of laboratory density determination and construction equations of state for marine waters with various ionic compositions and salinities was developed. The validation of the method was performed using the Ocean Standard Seawater and the UNESCO thermodynamic equation of state (EOS-80). Density measurements of water...

This article focuses on the interaction between the Ob- and Yenisei-dominated parts of the large Ob-Yenisei buoyant plume formed in the southern part of the Kara Sea during ice-free periods. It was shown that certain wind forcing and river discharge conditions cause the formation of a specific structure of the Ob-Yenisei plume with significantly di...

Distribution of Sea of Azov water on the Crimean shelf and its penetration into the Gulf of Feodosia result in significant changes in the hydrophysical and hydrochemical structure of the water area. This inflow is also estimated as a major source of anthropogenic pollution in the region. At the same time, the Gulf of Feodosia is one of the least in...

This article presents a new method of laboratory density determination and construction equations of state for marine waters with various ionic compositions and salinities was developed. The validation of the method was performed using the Ocean Standard Seawater and the UNESCO thermodynamic equation of state (EOS-80). Density measurements of water...

Studying of methane formation and distribution in natural waters is important for understanding of biogeochemical processes of carbon cycle, searching for oil and gas sections and evaluation of CH4 emissions for investigations of greenhouse effect. The Black Sea is the largest methane water body on our planet. However, relatively low values of meth...

The Aral Sea level dynamics research is an urgent scientiic task regarding to the fact that the environmental and anthropogenic mechanisms have induced dramatical change of water and salt balances for the last 50 years. Since late 1960s the sea volume has decreased by 90 % and its salinity has increased a lot. The Aral Sea hydrological cycle proces...

The Aral Sea, formerly one of the four largest lakes in the world, has lost over 90% of its volume during the dramatical dessication mainly caused by the severe alteration of water budget of the basin. Shrinkage of the Aral Sea resulted in profound changes of the lake’s ecosystem, that became a subject for a number of publications based on a wide r...

We present data of measurements of thermohaline and bio-optical fields in the surface layer of the Kara Sea carried out in September 2012, during the 59th cruise of the R.V Akademik Mstislav Keldysh. Measurements were performed during vessel motion along the expedition route using a pump-through CTD system (temperature and salinity) and UV fluoresc...

This paper is focused on the hydrophysical state of the western basin of the Large Aral Sea in its present conditions of ecological crisis. The investigation is based on the direct observations carried out during a field survey in the Aral Sea in October of 2013. The analysis of the distribution of the temperature values across the western basin is...

This paper presents the results of long-term in situ and satellite measurements at shelf areas adjacent to the estuaries of the small rivers of the Russian coast of the Black Sea (Mezyb, Pshada, Vulan, Tuapse, Bitkha, Sochi, Cudepsta, Mzymta). The quantitative haracteristics of the response of the hydrophysical and hydrochemical fields at the sea s...

The shrinkage of the Aral Sea in the second half of the past century has significantly affected the hydrophysical regime of the lake. The objective of this paper is to report on a hydrological structure and circulation of the today's Aral Sea based on both direct field observations and modeling results. We focus on the results of three field survey...

The Kara Sea, the marginal sea in the Arctic Ocean, receives a large volume of freshwater (1290 km3/year on long term average) from the Ob, Yenisey and other rivers. In consequence, a large part of sea's area is influenced by fresh water discharge. Spreading in the surface layer of the sea, continental runoff largely modulates spatial variability o...

The results of the 3 latest expeditions (2009 - 2011) of the Shirshov Institute to the Aral Sea are reported. We analyze the interannual variability of the basin circulation together with the thermohaline structure in order to identify the underlying mechanisms. The study is based on the results of the field surveys of August, 2009, September, 2010...

The results of the latest expedition of the Shirshov Institute to the Aral Sea are reported. The survey encompassed 15 field days in August, 2009. An interdisciplinary oceanographic study in the western basin of the sea was conducted during the expedition. Vertical profiles of temperature, salinity and fluorescence were obtained using a CTD profile...