Development Vernadsky’ works on natural waters: biosphere processes and water quality

Rudneva I.I., Gaisky P.V., Shaida V.G., Shaida O.V.

In the Crimean Peninsula, there are several hypersaline lakes that have hydromineral and biological resources. However, they are under a significant anthropogenic load, which together with the climate change leads to negative consequences for the ecosystems. The aim of the work was to study the seasonal changes of physicochemical parameters of water (temperature, pH, oxygen content, salinity, redox potential Eh, optical density and transparency) and Artemia population in Saki Lake in 2022. For the daily fluctuations of temperature, O2, CH4 and CO2, a vertical temperature profile measuring system was installed at the boundaries of the air, water and bottom at a depth of 4 m and with a spatial discreteness of 0.2 m. The drive sensors for the content of gases assay in the air were installed. The increase in salinity and Eh in summer was accompanied by an increase in air and water temperature. Simultaneously, decreases in oxygen content and pH in brine have been observed. Artemia cysts were found throughout the year, nauplii were mostly available during spring and autumn, and the adults were shown in summer. The obtained results demonstrated the seasonal fluctuations in the hypersaline ecosystem within the ongoing climate change, and they can be used for the development of the optimal management of the mineral and biological resources of such water bodies.

Moiseenko T.I., Bazova M.M., Gashkina N.A.

Small lakes are potentially effective environmental sensors; they react quickly to anthropogenic stressors. We studied the long-term response of water chemistry to reduced acid deposition and climate warming in the Kola Arctic region of Russia based on monitoring data from 75 lakes. Monitoring was carried out once every 4–5 years in 1990–2018, with analysis for major anions and cations, dissolved organic carbon (DOC), and heavy metals (Ni and Cu). Analysis of archive data on the weather allowed us to reliably identify trends toward a systematic temperature increase over the past 28 years. The population of the lakes under study was proven to generally show a decrease in the concentrations of anthropogenic sulfates and the strengthening of the acid-neutralizing capacity (ANC) of the waters during this period. The concentrations of both DOC and nutrients (Ptot and Ntot) in the lake waters were determined to increase. This phenomenon can be explained by the following two mechanisms: a decrease in the deposition of strong acids and climate warming. We suggest that the effects of multiple factors on the surface waters result in an irreversible evolution of the lakes; hence, the term recovery does not adequately reflect the processes occurring in this industrially well-developed part of the Arctic.

Gashkina N.A., Moiseenko T.I., Shuman L.A., Koroleva I.M.

Bioaccumulation of the main pollutants in the organs of whitefish, as well as their haematological parameters, were examined dynamically over a 40-year period in historically contaminated Lake Imandra. A quantitative histological analysis was performed to assess the physiological state of whitefish and histopathologies of organs, as well as their physiological and biochemical functions in the current period of toxic load decline. Biological reactions of whitefish from the historically contaminated area have been greatly modified in contrast to those of whitefish from the never contaminated area of the lake, and this shift persisted even after approximately 20 years of toxic load decline. First, high antioxidant status supports the body's systems, smoothing over the negative consequences of metal toxicity, phagocytosis and inflammatory reactions. Moreover, the defence mechanism of whitefish from the historically contaminated area actively uses the oxidative systems of nonspecific immunity. Second, the adaptive strategy is aimed at improving gas exchange without compensatory proliferation of gill structure, which increases their functional surface and reduces the distance to the bloodstream, as well as increasing haemoglobin in maturing erythrocytes. Third, the higher efficiency of endo- and phagocytosis was confirmed by detecting increased monocytes and macrophages in the peripheral blood and decreased melano-macrophage centres in the fish kidney. Elevated accumulation of Fe, Cu, and Se may serve a sign of liver pathology, while elevated accumulation of Zn and Co already indicates kidney pathology, which is confirmed by histopathological alterations. • Biological reactions of whitefish from historically contaminated area have been modified: • high antioxidant status supports the body's systems. • oxidative systems of nonspecific immunity dominate in protective functions. • adaptive strategy is aimed at improving gas exchange and increasing haemoglobin in erythrocytes. • high efficiency of endo- and phagocytosis is typical for fish.

Malkova G., Drozdov D., Vasiliev A., Gravis A., Kraev G., Korostelev Y., Nikitin K., Orekhov P., Ponomareva O., Romanovsky V., Sadurtdinov M., Shein A., Skvortsov A., Sudakova M., Tsarev A.

Climate warming in the Russian Arctic over the past 40 years shows a variety of patterns at different locations and time periods. In the second half of the 20th century, the maximum rates of warming were characteristic of the subarctic permafrost regions of Russia. But in the 21st century, the locations of the greatest rates of climate warming moved to the Arctic zone of Russia. It was one of the reasons for a sharp increase in permafrost temperatures, an increase in the depth of seasonal thaw, and the formation of closed taliks. It was found that as a result of climate change, the differences in permafrost temperatures between different cryogenic landscapes in the area of continuous and discontinuous permafrost distribution have decreased, and in the area of sporadic permafrost distribution are now practically absent. The thermal regime of the ground shows dramatic changes everywhere with a pronounced reduction in the depth of zero annual amplitude.

de Wit H.A., Stoddard J.L., Monteith D.T., Sample J.E., Austnes K., Couture S., Fölster J., Higgins S.N., Houle D., Hruška J., Krám P., Kopáček J., Paterson A.M., Valinia S., Van Dam H., et. al.

Abstract Surface water browning, the result of increasing concentrations of dissolved organic matter (DOM), has been widespread in northern ecosystems in recent decades. Here, we assess a database of 426 undisturbed headwater lakes and streams in Europe and North America for evidence of trends in DOM between 1990 and 2016. We describe contrasting changes in DOM trends in Europe (decelerating) and North America (accelerating), which are consistent with organic matter solubility responses to declines in sulfate deposition. While earlier trends (1990–2004) were almost entirely related to changes in atmospheric chemistry, climatic and chemical drivers were equally important in explaining recent DOM trends (2002–2016). We estimate that riverine DOM export from northern ecosystems increased by 27% during the study period. Increased summer precipitation strengthened upward dissolved organic carbon trends while warming apparently damped browning. Our results suggest strong but changing influences of air quality and climate on the terrestrial carbon cycle, and on the magnitude of carbon export from land to water.

Vasseur P., Masfaraud J., Blaise C.

Ecotoxicology is a discipline resulting from pollution events that harmed human and environmental health by the mid-twentieth century. Environmental considerations were simply inexistent at this time, and inevitably deleterious effects and environmental disasters followed. These historical events, like Clear Lake disaster in California, will be recalled, as well as new concepts developed, and scientists involved in these findings. A special tribute is given to Professor Jean-Michel Jouany who conceptualized newly acquired knowledge into an emerging discipline, which he named “ecotoxicology” in the 1960s, and understood to be “toxicology in an ecological perspective.” However, René Truhaut is considered as the “father of ecotoxicology” by posterity, while his young mentor Jouany was shadowed by the latter. It is timely to “open the book” as concerns these two exceptional personalities and their working relationships, first to set the record straight and second to give credit where credit is due.

Rudneva I.I., Zalevskaya I.N., Shaida V.G., Memetlaeva G.N., Scherba A.V.

The paper presents data on seasonal fluctuations in hydrochemical characteristics and the supply dynamics of biogenic elements in four hypersaline lakes in Crimea: Sasyk-Sivash, Oiburg, Konrad, and Sakskoe (eastern basin) in 2017. The migration pathways of biogenic elements in the hypersaline lakes are determined depending of natural and anthropogenic factors. The role of the elements in ecosystem processes, the formation of peloids, and the functioning of communities of organisms are discussed. Probable transformation scenarios of the ecosystems of saline lakes are considered as a function of climatic changes, increasing anthropogenic load, and related increase in the inflow of biogenic elements.

Meingast K.M., Kane E.S., Coble A.A., Marcarelli A.M., Toczydlowski D.

Abstract Increasing concentrations of dissolved organic carbon (DOC) have been identified in many freshwater systems over the last three decades. Studies have generally nominated atmospheric deposition as the key driver of this trend, with changes in climatic factors also contributing. However, there is still much uncertainty concerning net effects of these drivers on DOC concentrations and export dynamics. Changes in climate and climate mediated snowfall dynamics in northern latitudes have not been widely considered as causal factors of changes in long-term DOC trends, despite their disproportionate role in annual DOC export. We leveraged long-term datasets (1988–2013) from a first-order forested tributary of Lake Superior to understand causal factors of changes in DOC concentrations and exports from the watershed, by simultaneously evaluating atmospheric deposition, temperature, snowmelt timing, and runoff. We observed increases in DOC concentrations of approximately 0.14 mg C l−1 yr−1 (mean = 8.12 mg C l−1) that were related with declines in sulfate deposition (0.03 mg SO 4 2 − l−1 yr−1). Path analysis revealed that DOC exports were driven by runoff related to snowmelt, with peak snow water equivalences generally being lower and less variable in the 21st century, compared with the 1980s and 1990s. Mean temperatures were negatively related (direct effects) to maximum snow water equivalences (−0.71), and in turn had negative effects on DOC concentrations (−0.58), the timing of maximum discharge (−0.89) and DOC exports (indirect effect, −0.41). Based on these trends, any future changes in climate that lessen the dominance of snowmelt on annual runoff dynamics—including an earlier peak discharge—would decrease annual DOC export in snowmelt dominated systems. Together, these findings further illustrate complex interactions between climate and atmospheric deposition in carbon cycle processes, and highlight the importance of long-term monitoring efforts for understanding the consequences of a changing climate.

Moiseenko T.I., Gashkina N.A., Dinu M.I.

Abstract This paper presents metal speciation calculations that are based on mathematical modelling of chemical reactions in natural waters. Metal concentrations (Hg, Cd, Pb, Ni, Cu, Al, Sr) were determined, and their speciation in water were calculated for 22 water areas in the Kola region. Meanwhile, the accumulation of metals in fish organs and tissues was studied (e.g. whitefish). The biogeochemical activity of metals determines the proportions of labile and non-labile speciation in water. In the distribution zones of non-ferrous industry effluents, metal aqua-ions prevail; during the distribution, the proportions change in accordance with the metal activity. The bioavailability of metal speciation is estimated depending on aqueous geochemical conditions and, accordingly, the speciation of metals (in situ), based on the original studies of the lakes of the Kola region in northern Russia. The connection among the metal contents in fish and water has been identified using multidimensional scaling and redundancy analysis techniques. Using the example of natural conditions in northern low-salinity freshwaters, it is demonstrated that labile Cd, Pb, Ni, Cu, Al, and Sr are the species most bioavailable and able to penetrate fish; meanwhile, the organic complexes of Hg, Pb, and Al have a greater affinity to accumulation in the gills. This study demonstrates the need to correct the approved water quality standards in Russia, taking into account the high bioavailability of metals in northern low-salinity waters.

Руднева И.И., Залевская И.Н., Шайда В.Г., Меметлаева Г.Н., Щерба А.В.

Tussupova K., Anchita A., Hjorth P., Moravej M.

Decrease of saline lakes, which comprise 44% of all available lake water, is a major concern. It additionally accelerates the desertification process of the region. Thus, various countries have taken different actions in protecting their lake water levels. The aim of this paper is to assess different strategies directed to tackle the decreased lake water levels in Lake Urmia and the Aral Sea, which split into the North Aral Sea and South Aral Sea. These are among the world’s largest and fastest drying saline lakes observed in the past 50 years and have both reduced to 10% of their original size. The paper presents a thorough review of academic reports, official documents, and databases. Although the dry-up of a lake is a natural process, it has been sped up by human interventions in the hydrological cycle. Dust storms (strong winds) cause problems in the surroundings. In the case of the Aral Sea, they transmit the pollutants from the dry lake bed causing severe health issues. Various strategies were implemented to manage the socio-economic conditions caused due to the drying of lakes. The strategy implemented for the North Aral Sea was to restore the lake by reducing the water withdrawals from the Syr Darya river, which lead to increased water inflow to the sea. The suggested strategy for Lake Urmia was to restore the lake by water transfer activities from various water sources. These projects have not yet been realized. The strategy implemented for the South Aral Sea was to use a dry lake bed to diversify the economy by oil and mineral extraction along with developing a tourist industry based on the considerable interest to come and observe an ecological disaster of such monumental proportions. These findings show that there is no common best solution for this type of problem. The best fit depends on the local context and it is strongly path-dependent.

Zhang X., Davidson E.A., Zou T., Lassaletta L., Quan Z., Li T., Zhang W.

Moiseenko T., Sharov A.

In this paper, retrospective analyses of long-term changes in the aquatic ecosystem of Ladoga, Onega, and Imandra lakes, situated within North-West Russia, are presented. At the beginning of the last century, the lakes were oligotrophic, freshwater and similar in origin in terms of the chemical composition of waters and aquatic fauna. Three stages were identified in this study: reference condition, intensive pollution and degradation, and decreasing pollution and revitalization. Similar changes in polluted bays were detected, for which a significant decrease in their oligotrophic nature, the dominance of eurybiont species, their biodiversity under toxic substances and nutrients, were noted. The lakes have been recolonized by northern species following pollution reduction over the past 20 years. There have been replacements in dominant complexes, an increase in the biodiversity of communities, with the emergence of more southern forms of introduced species. The path of ecosystem transformation during and after the anthropogenic stress compares with the regularities of ecosystem successions: from the natural state through the developmental stage to a more stable mature modification, with significantly different natural characteristics. A peculiarity of the newly formed ecosystems is the change in structure and the higher productivity of biological communities, explained by the stability of the newly formed biogeochemical nutrient cycles, as well as climate warming.

Moiseenko T.I.

Bioavailability and ecotoxicity of metals and their relation to geochemical conditions in aquatic environments were considered. It was shown that free ions are the most penetrative species of most metals, except for organometallic complexes of some metals, for example, mercury. We analyzed models for the assessment of the hazard of metal contamination of water environments using the results of thermodynamic calculations of free ion concentrations, the ability of biological receptors to bind them, and the toxic properties of the metals. A concept was developed on the main mechanisms of metal penetration and excretion and cytotoxicity of nonessential elements. A new method was proposed for the estimation of critical levels of polymetallic contamination of water on the basis of measurements of water complexation capacity and determination of the dose–effect relations between the integrated characteristics of the polymetallic contamination and indicators of the health of the ecosystems (in situ) from the results of investigations in the northern Kola Peninsula.