Hydrochemical Characterization of Nabeghlavi Underground Mineral Waters

Georgia is rich in groundwater deposits, which renew over time and are characterized by the best indicators of water quality and a stable regime. Groundwater is one of the main natural productive forces of Georgia, which plays an important role in the economic development and export industry. During 2015–2020, chemical composition of the Nabeghlavi mineral waters has been studied by the means of the modern unified methods. Almost all data from previous chemical analyzes have also been retrieved and systematized/collated. Using mathematical statistical analysis, the maximum, minimum, and mean arithmetic values of the major and specific components of water and the empirical deviation from the arithmetic mean have been calculated. Though comparison of the recent and historic data on chemical composition, based on the results of statistical analysis of the major ions, the natural fluctuation limits of the waters and stability of waters from all exploitation drill holes have been shown. According to the chemical composition and total mineralization there are three groups of waters in fresh and low mineralized category. It is shown that chemical composition of water from all exploitation drill holes meets requirements for the natural mineral water category, both the normative document of Georgia and directive of the European Commission.

Pilot Studies of the Unique Highland Palsa Mire in Western Sayan (Tuva Republic, Russian Federation)

In contrast to the well-studied West Siberian sector of frozen bogs in the Russian Arctic, the frozen mound bogs (so-called “palsas”) on the highlands of Southern Siberia have not yet been studied, but they are suspected to be even more sensitive to ongoing climate change. This article provides the pilot study on palsa mire Kara-Sug in the highland areas of Western Sayan mountain system, Tuva Republic. The study focuses on the current state of palsa mire and surrounding landscapes, providing wide range of ecological characteristics while describing ongoing transformations of natural landscapes under a changing climate. The study used a variety of field and laboratory methods: the integrated landscape-ecological approach, the study of peat deposits, geobotanical analysis, and modern analysis of the chemical composition of water, peat, and soils. The study shows that highland palsa mires are distinguished by their compactness and high variety of cryogenic landforms leading to high floristic and ecosystem diversity compared with lowland palsa mires. This information brings new insights and contributes to a better understanding of extrazonal highland palsa mires, which remain a “white spot” in the global environmental sciences.

Culture-Independent Survey of Thermophilic Microbial Communities of the North Caucasus

The Greater Caucasus is a part of seismically active Alpine–Himalayan orogenic belt and has been a center of significant volcanic activity during the Quaternary period. That led to the formation of the number of hydrothermal habitats, including subterranean thermal aquifers and surface hot springs. However, there are only a limited number of scientific works reporting on the microbial communities of these habitats. Moreover, all these reports concern only studies of specific microbial taxa, carried out using classical cultivation approaches. In this work, we present first culture-independent study of hydrotherms in the Republic of North Ossetia-Alania, located in the southern part of the North Caucasus. Using 16S metabarcoding, we analyzed the composition of the microbial communities of two subterranean thermal aquifers and terrestrial hot springs of the Karmadon valley. Analysis of correlations between the chemical composition of water and the representation of key taxa allowed us to identify the key factors determining the formation of microbial communities. In addition, we were able to identify a significant number of highly abundant deep phylogenetic lineages. Our study represents a first glance on the thermophilic microbial communities of the North Caucasus and may serve as a basis for further microbiological studies of the extreme habitats of this region.

The content of heavy metals in the water of Lake Gusinoe (Western Transbaikalia) and its tributaries

Investigation of the transformation of substances in the basin of the Selenga River, the main tributary of Lake Baikal, due to anthropogenic impact under conditions of global climate change, is especially important for Lake Baikal which is a World Natural Heritage Site and the main source of fresh drinking water not only in the region, but also in the world. One of the key research objects in the Selenga River basin, which is subject to significant anthropogenic impact, is the ecosystem of Lake Gusinoe. This study presents the results of analysis of the physical and chemical parameters of the water mass of Gusinoe Lake basin. for the period from 2017 to 2020. Thus, the results on hydrochemical indicators for a long-term period of research of the lake show changes in the chemical composition of water and the concentration of main ions. In 2020, the content of almost all metals was higher than in 2017-2020, which may be due to the rise in the level of Lake Gusinoe and groundwater that began in 2019 and continued in 2020, as a result of rain floods that caused flooding of the coastal territories and the entry of pollutants into watercourses and the lake.

Chemical component depositions in the microbial mats and travertine in the Khoito-Gol thermal spring (Eastern Sayan)

The results of studies of the chemical composition of water, travertine, and microbial mats in the Khoito-Gol mineral spring (Eastern Sayan) are presented. It was shown that the formation of mineral deposits, travertine, and microbial mat is connected with the active functioning of microorganisms and geological and geodynamic conditions. It has been revealed that the diversity of cyanobacterial and sulfur microbial mats increases as the distance from the springs of the thermal water grows. Microbial mats are hardened with carbonates being converted into solid travertine crusts that are built upon the top of older structures to form multi-meter domes. The concentration function of the microbial mats and thermal water showed higher coefficients of accumulation of nickel and beryllium.

Solute transport and solutional denu-dation rate of carbonate karst in the semi-arid Zagros region (southwes-tern Iran)

We conducted a one-year-long study of solute load measured three times per month in three neighboring subwatersheds (Alashtar, Khorram Abad, and Biranshahr) located in the Karkheh River basin in the Zagros region of southwestern Iran. Research was focused on the chemical composition of water (solute load), karst denudation rate, spatial and temporal variability, as well as comparison of solute load with suspended load. Results show that Ca-Mg-HCO3 is the dominant water type that reflects the lithological characteristics of the catchment areas. Lack of seasonal fluctuation of solute load and absence of dilution during high water levels but evident seasonal course of discharge defines the highest solute flux during the annual maximum of discharge in spring months. The highest solute flux is related to flood events. High annual variation of Na1 concentration compared to conservative Cl2 as well as Chloro-Alkali indexes (CAI and CAI2) suggests that Na1 adsorption and desorption during ion-exchange reactions occur in the regolith. This Na+ variability, to some extent, explains weak Ca21 and Mg21 dilution effect during high water levels. During the measurement period (2014-2015), solute flux calculated per catchment area amounted to 49-69 t km-2 a-1 (tons per km per year). The chemical composition of water and discharge shows by far the highest chemical denudation of limestones and dolomites (87−89 %), while dissolution of gypsum is of minor importance (11−13 %). As a result, the carbonate karst solutional denudation rate is between 0.010 and 0.040 mm a21 , where the higher values are more probable for longer periods due to the relatively low discharge during the spring of 2015. Comparison of dissolved and suspended loads indicates that the transport of suspended load is an order of magnitude less than transport of the dissolved load; the only exception is one flash flood event when suspended load exceeded the dissolved load. Besides a small decrease in solute flux as well as carbonate karst dissolution rates from NW to SE, no large hydrochemical differences between the three subwatersheds were detected.

Structural problems of water metabolism in the human body

The article highlights the main biochemical processes that determine the normal functioning of the body and depend on the chemical composition of water consumed by humans. The lack and excess of water, as well as certain features of its composition affect the human body.