Studied Water Bodies Research Articles

Distribution of radionuclides in modern sediments of the rivers flowing into the Dnieper-Bug Estuary

The article presents the results of large-scale studies of the content and distribution of natural and man-made radionuclides in the sediments of the rivers flowing into the Dnieper-Bug estuary. The article also presents the results of the granulometric analysis of the surveyed water bodies. The data about natural radioactive elements in the sediments rivers flowing into the Dnieper-Bug estuary obtained in this research are demonstrated moderate specific activity, which, however, clearly correlates with the granulometric composition of sediments. The 137Cs determined by us is contained in the sediments of all studied water bodies and the places of it greatest concentration coincide with the areas in which the sediment is represented mainly by the pelitic fraction. The data obtained in this research can serve as a baseline data in natural radionuclides concentration in sediments rivers flowing into the Dnieper-Bug estuary. The obtained data can also be used for further monitoring of the specific activity of man-made radionuclides, in particular 137Cs.

Ecological drivers of Odonata beta diversity in arid and semi‐arid regions of the Central Plateau of Iran

Abstract Freshwater habitats are among the most threatened and least studied habitats in arid regions of Iran. Discovering factors responsible for the spatial variation of biodiversity are one of the main considerations in conservation biology. As a first step towards developing conservation strategies, we aimed to investigate the beta diversity and response of Odonata assemblages to climate and landscape variables in arid and semi‐arid regions of Iran. A total of 120 water bodies were surveyed. The beta diversity distance matrices were calculated for Odonata, Anisoptera, and Zygoptera, using the Jaccard dissimilarity coefficient. Also, the replacement and richness difference components of Odonata beta diversity were computed. Each of the five dissimilarity matrices was modelled by generalised dissimilarity modelling (GDM). We recorded 58 species of Odonata that represent 58% of the Odonata species in Iran. The average total beta diversity was high (0.873). GDMs results showed that the most influential variables varied between the replacement and richness difference components of Odonata beta diversity as well as between the two Odonata suborders. Anisoptera were most strongly affected by the temperature annual range, while the most important variable for Zygoptera was the average wind speed in April. Our results suggest that the studies of the drivers of biodiversity patterns benefit from beta diversity partitioning also from comparing species groups with different ecological preferences. The high biodiversity of the studied water bodies as well as the anthropogenic and climate threats that they are faced with, make these ecosystems a conservation priority.

Planktonic Invertebrates in the Assessment of Long-Term Change in Water Quality of the Sorbulak Wastewater Disposal System (Kazakhstan)

The multicomponent composition of wastewater makes it challenging to assess its quality objectively, but the last one is a prerequisite for the safe re-use of wastewater. The solution to this problem should be aimed at finding criteria that make it possible to increase the objectivity of assessing the water quality of reservoirs with multicomponent pollution. This work analyzes the water quality of the Sorbulak wastewater disposal system in the summer of 2017, based on chemical variables and zooplankton structure and assess the long-term changes in the water quality of Sorbulak. According to the Kruskal–Wallis test, in 2017, the differences between the studied water bodies in the content of nutrients and heavy metals were mostly insignificant. From 2000–2002 to 2017, nitrate, nitrite nitrogen, and heavy metals in Sorbulak significantly decreased. Zooplankton communities consisted of a relatively small number of eurybiontic species resistant to environmental factors. The variability of the quantitative variables of zooplankton was associated with the nutrients. Males dominated the population of the cyclopoid copepods Acanthocyclops trajani. In 2000–2002 individuals with morphological anomalies were found in cyclopoid copepods populations, but were absent in 2017. The appearance of individuals with morphological anomalies was associated with copper or lead. The chemical data and structure of zooplankton communities indicated that the toxic pollution of Sorbulak decreased by 2017 compared to 2000–2002. Our results demonstrate that the structural variables of zooplankton communities could be successfully used to assess the water quality of water bodies with mixed pollution. We recommend using not only the traditional set of biological variables (abundance, biomass, diversity indices, and the average mass of an individual), but also data on the structure of species dominance, the sex structure of copepod populations, and the presence of individuals with morphological anomalies for monitoring of water bodies with mixed pollution.

Ecological evaluation of natural water bodies in the south part of Noginscky Region Moscow District

Floristic composition of terrestrial and aquatic plants in the ecotopes of surface water bodies, Blue Lakes and Lake Biserovo, was studied to assess environmental health of aquatic ecosystems in the Moscow region. The research was carried out both in the field and in the laboratory. Blue Lakes were lacking aquatic vegetation and the dominant synusia of the following plant species was found along the coastal zone: meadow clover (Trifolium pratense L.), meadow bluegrass (Poa pratensis L.), sedge coastal (Carex riparia Curt.), chamomile (Matricaria chamomilla L.), plantain (Plantago major L.), Timothy meadow (Phleum pratense L.). The vegetation cover of Lake Biserovo was patchy: submerged vegetation was most widespread, Canadian Elodea (Elodea canadensis Michx.) was the dominant species. Pure thickets of vegetation were formed only by the common American water plantain(Alisma plantago-aquatica L.), lake cattail (Schoenoplectus lacustris L.), common reed (Phragmites communis Trin.) and sedge coastal (Carex riparia Curt). It should be noted that in all the studied water bodies, the pH of the water area can be classified as very clean: Blue Lakes (7.8), samples from Lake Biserov (8.32). Water samples from Lake Biserova had the highest turbidity (11.5), which was associated with the accumulation of particles of the silt fraction of the reservoir, which began the process of eutrophication, high anthropogenic load. According to the results of a comprehensive assessment (hydrological indicators, calculation of the Mayer index) of the studied samples from the reservoirs, it was concluded that the water area of the Blue Lake had the best environmental status in the Noginsk region.

Structure and Dynamics of Mollusk Communities of Small Oxbow Lakes and the Determining Factors (the Khoper River Valley, Penza Oblast)

The structure and dynamics of mollusk communities, as well as environmental factors influencing them, were analyzed in small oxbow lakes of the forest-steppe zone (a case of the Khoper river valley, Penza region, Russian Federation). 19 species of mollusks were found in the studied water bodies. The oxbow lakes were characterized by relatively low alpha-diversity (number of species 4 ± 2) and relatively high beta-diversity (Jacquard index 0.26 ± 0.18), which is typical for floodplain ecosystems. Lake communities were dominated by Planorbis planorbis (40%), Lymnaea stagnalis (15%), Anisus spirorbis (14%), Lymnaea saridalensis (9%), Anisus vortex (8%). The results of our analysis showed that the group of factors that determined the type of water body (stability, light intensity, water temperature, oxygen concentrations) had the greatest impact on the structure of malacocenoses. The seasonal dynamics of mollusk communities was determined by the number of adjoining water bodies, water temperature, and dissolved oxygen concentrations. The number of adjoining oxbows was the major factor influencing mollusk species diversity, as well as the total number and biomass of mollusks. Oxbow isolation was favorable for mollusk communities. The factors influencing the highest number of mollusks species (seven) were the light intensity and the presence of fish. Other significant factors were the stability of lakes (shown for five species of mollusks), the number of adjoining oxbows and water transparency (four species). Aquatic vegetation positively correlated with the abundance of only one species—Anisus vortex. Our data suggest that the presence of fish could influence the abundance of Lymnaea saridalensis. The mollusks, in their turn, apparently, had a positive effect on the abundance of leeches in water bodies. Mollusk species most sensitive to the external factors were Lymnaea stagnalis, Lymnaea saridalensis, Aplexa turrita, Anisus spirorbis and Anisus leucostoma, most tolerant were Bathyomphalus crassus, Anisus vortex, Planorbis planorbis and Planorbarius corneus.

Флора и ее анализ. Гидрофильные растения разнотипных водоемов Самаркандской области (Узбекистан)

Aquatic and coastal aquatic plants are one of the most important components of aquatic ecosystems. Therefore, at present, much attention is paid to the issues of rational use and development of the country's inland water bodies. Together with phytoplankton, this group of plants participates in the trophic cycle of biocenosis, providing various stages of the links of the food chain with appropriate products. For example, the plants of reservoirs serve as food for representatives of different taxonomic groups of animals, mollusks, crustaceans, insects, fish, birds and mammals. With moderate overgrowing of water bodies, favorable conditions are formed for the development of the phytophilous fauna of invertebrates. The flora of higher aquatic and coastal plants of the Samarkand region has not yet been fully studied. The species composition was not studied, taxonomic and floristic analysis was not carried out. In addition, it is very rare to find detailed information about the use of aquatic plants in the national economy, information about useful species and rare species common in this territory. The article presents the results of research on the study of aquatic and coastal plants of reservoirs of the Samarkand region. It was revealed that 72 species of aquatic and coastal plants, which belong to 51 genera, 34 families and 5 classes, grow in reservoirs of various types on the territory of the Samarkand region. Representatives of the families Potamogetonaceae, Poaceae, Cyperaceae and Polygonaceae make up 43% of the total number of plants of this group growing in the studied region. In terms of life forms, about 12.5% (9 species) are annuals, and 77.8% (56 species) are perennials. It was found that 7 species of aquatic mosses grow in the studied water bodies.

TIME-SPACE ASSESSMENT OF WATER QUALITY OF MIASS RIVER

The pollution of natural waters, both sea and fresh, is a crucial issue all over the world. Most of the large and small rivers, streams, and reservoirs almost in every federal district of the Russian Federation are characterized as polluted and dirty. The Miass River is one of the main among the large rivers in South Ural. The ecological state of the river is characterised as bad. This work assesses a thirteen-year change of water quality in the Miass River and Argazinskoe and Shershnevskoe reservoirs, which are the source of drinking water for the residential area of the Chelyabinsk region. The river water is used to provide the cities and towns of the region, as well as numerous industrial and farming enterprises with water. Besides, effluents are discharged into the Miass river along its whole length. The results of many years of observation have shown, that heavy metals and biogenic substances are the main pollutants for the river. This work aims toanalyse episodes of high and extremely high pollution of the water bodies. Episodes of high and extremely high levels of Cu, Zn and Mn are recorded annually at dam part of Argazinskoe reservoir. Episodes of high and extremely high levels of biogenic elements are recorded for the stretches of the river downstream of Chelyabinsk. Currently, some measures within the project «Clean Water» are planned to improve water quality in the studied water bodies.

Detecting an Alien Reptile through Parasitological Analysis of the Widely Distributed Alien Fish Perccottus glenii

The current geographical distribution of alien terrapins is poorly understood because these reptiles are difficult to detect in large natural water bodies, as they don’t vocalize, have cryptic coloration, and are typically not numerous in temperate climate. The present study tests the previously unconfirmed oral reports suggesting the presence of terrapins in several urban water bodies in the European part of Russia, which is outside the geographical ranges of native European terrapins. We assessed the presence of the terrapins indirectly, by using a parasitological analysis of a widespread alien fish Perccottus glenii which is numerous in shallow lentic water bodies. This fish can harbour diverse parasitic species. We detected the alien nematode Spiroxys sp. in the wall of the digestive tract of the studied fish. The life cycle of this nematode includes freshwater terrapins as the obligatory definitive host. Thus, detecting Spiroxys sp. in P. glenii indicates the presence of terrapins in three of the studied water bodies. This approach will be particularly valuable when the direct detection of alien terrapins is limited by the seasonality, weather, macrophyte densities, landscape features, or other factors. The discussed indirect method is an additional tool for confirming the presence of alien terrapins in water bodies in the European regions, where native terrapins are absent.

Holy waters in the Podlasie region, Poland, as a witness of hydrological and hydrochemical changes

In the lowlands, springs are quite rare. In the north-eastern Poland, many springs are attributed miraculous properties and water is considered sacred. Due to their cultural and spiritual importance they have survived to present times. Thus, they can be used to study the hydrological and hydrochemical changes in the aquifer. The level of hydrological and hydrochemical changes of the first aquifer in the North Podlasie Lowland has been assessed.We have studied 25 springs and wells considered holy waters, historically present in the geographical region of the North Podlasie Lowland. The main hydro- and physicio-chemical parameters were measured. Currently, majority of the springs have been transformed into shallow dug wells due to groundwater level lowering; only in few cases (6) did the springs survived as groundwater outflows. Their performance was relatively small; from 0.3 dm3ˑs−1. The remaining objects (19) are different depth wells capturing the first aquifer. The largest lowering of groundwater level, exceeding 3 m, was found in Bielska Plain.Their waters were characterized by excessive iron concentration, typical for shallow groundwater of the Quaternary aquifer, and increased concentration of biogenic elements associated with agricultural activity and natural processes contribute, therefore using it as a drinking water requires treatment. Elevated concentrations of DOC, nitrogen and phosphorus compounds could have been caused by changes in hydrological conditions in the region, transformation of the a spring niche through housing of the outflow or presence of surrounding buildings. The studied water bodies were of the bicarbonate-calcium type.

Response of phytoplankton to heavy pollution of water bodies

Abstract Phytoplankton structure was studied in five ponds (located in the Oleksandriya Nature Park, Ukraine), which significantly differed in the level of their contamination. The concentration of ammonium (NH4 +-N) in the studied water bodies was 0.02–74.00 mg l−1, of nitrite (NO2 −-N) – 0.002–1.750 mg l−1, nitrate (NO3 −-N) – 0.13–58.00 mg l−1, inorganic compounds of phosphorus (Pinorg) – 0.041–0.160 mg l−1, chloride (Cl−) – 35.4–560.5 mg l−1, whereas the content of organic matter (PO and DO) – 4.4–10.4 and 18.0–81.0 mg O l−1, respectively. It has been found that the response of phytoplankton to heavy pollution consisted in changes in its species richness, taxonomic structure, species composition, quantitative indices, numbers and biomass structure, dimensional structure, pigment index, dominant complex, as well as changes in its ecological spectrum. Individual divisions of algae differed in their response to heavy pollution of water bodies, which was conditioned by the specificity of algae metabolism. Bacillariophyta and Cyanoprokaryota proved to be more sensitive to contamination, whereas Chlorophyta and Euglenophyta – more tolerant. The obtained data can be used to monitor the status of water bodies and their biota and to determine the type and intensity of contamination.

Effect of Diverse Abiotic Conditions on the Structure and Biodiversity of Ichthyofauna in Small, Natural Water Bodies Located on Agricultural Lands

Mid-field natural ponds promote regional biodiversity, providing alternative habitats for many valuable animal species. The study’s objective was to determine the most important abiotic factors, including hydrochemical and morphometric parameters, affecting fish occurrence in natural, small water bodies on agricultural lands. The studies were conducted in nine randomly selected water bodies located in Poland (the North European Plain). Eleven species of fish were recorded in the waterbodies, with the most abundant being cyprinids (mainly crucian carp). Canonical correspondence analysis (CCA) showed that an increase in oxygenation, temperature, amount of macrophytes, and K concentration and a decrease in the concentration of phosphates, electrical conductivity (EC), Mg, and Cl is associated with the most beneficial living conditions for the most frequently occurring species in the studied water bodies—crucian carp and tench. Aside from the hydrochemical parameters of water in the natural ponds, the number of fish correlates with the basin area and the pond area, maximum depth, area of the buffer zone surrounding the water bodies, and the number of macrophytes. This last factor also has a significant influence on the species’ abundance in the water bodies. Fish occurrences in mid-field ponds and common knowledge on their important role in the environment require taking steps to provide fish protection.

Characterization of SWOT Water Level Errors on Seine Reservoirs and La Bassée Gravel Pits: Impacts on Water Surface Energy Budget Modeling

The Surface Water and Ocean Topography (SWOT) space mission will map surface area and water level changes in lakes at the global scale. Such new data are of great interest to better understand and model lake dynamics as well as to improve water management. In this study, we used the large-scale SWOT simulator developed at the French Space National Center (CNES) to estimate the expected measurement errors of the water level of different water bodies in France. These water bodies include five large reservoirs of the Seine River and numerous small gravel pits located in the Seine alluvial plain of La Bassée upstream of the city of Paris. The results show that the SWOT mission will allow to observe water levels with a precision of a few tens of centimeters (10 cm for the largest water reservoir (Orient), 23 km2), even for the small gravel pits of size of a few hectares (standard deviation error lower than 0.25 m for water bodies larger than 6 ha). The benefit of the temporal sampling for water level monitoring is also highlighted on time series of pseudo-observations based on real measurements perturbed with the simulated noise errors. Then, the added value of these future data for the simulation of lake energy budgets is shown using the FLake lake model through sensitivity experiments. Results show that the SWOT data will help to model the surface temperature of the studied water bodies with a precision better than 0.5 K and the evaporation with an accuracy better than 0.2 mm/day. These large improvements compared to the errors obtained when a constant water level is prescribed (1.2 K and 0.6 mm/day) demonstrate the potential of SWOT for monitoring the lake energy budgets at global scale in addition to the other foreseen applications in operational reservoir management.

Trace Elements in the Bottom Sediments of the Crimean Saline Lakes. Is It Possible to Explain Their Concentration Variability?

Knowledge of trace elements content and their behavior in aquatic ecosystems is important for their sustainable use. There is a lack of such data for saline and, especially, hypersaline lakes and lagoons. Concentrations of more than 20 elements were evaluated in bottom sediments of 15 saline/hypersaline lakes and Lagoon Sivash in Crimea. An average salinity varied from 4 to 335 g/L in studied water bodies. The concentration of the trace elements varied from lake to lake. The highest variability was recorded for Cd, from 4.13 mg/kg to below the detectable level (CV = 1.463), and for Se, from 5.52 to 0.05 mg/kg (CV = 1.053). The lowest variability demonstrated by Cr, from 368 to 17 mg/kg (CV = 0.463), and by V, from 67.8 to 1.7 mg/kg (CV = 0.481). According to the found content of studied elements, all lakes were separated into three groups, and Lagoon Sivash was not included in these clusters. Salinity affected the concentration of some elements in bottom sediments, and this effect was not linear or unidirectional. In some cases, the action of other factors, often unknown, masked the effect of salinity. The geochemical background affects the structure and functioning of aquatic ecosystems, but the state of these ecosystems can significantly modify this background. An understanding of the differences in the elemental composition of bottom sediments in different lakes is possible only based on an integrated consideration of the interaction of all landscape, intra-ecosystem, and anthropogenic processes and factors that can influence this.

Remote sensing, GIS, and Fieldwork Studies to assess and valorize groundwater resources in the springs area of oum-Er-rabiaa (moroccan Middle Atlas)

The basin of Oum-Er-Rabiaa is part of the Middle Atlas, it constitutes an important water resource on the scale of Morocco. The hydrogeological system of the region is characterized by many springs, some of which have a high salinity rate spilling into Oum-Er-Rabiaa river. The present study aims to investigate: Firstly, the distribution of lineaments along the major shear corridors crossing the area as well as their hydrogeological importance, and secondly, to verify the influence of geological characteristics on the physicochemical properties of the studied water bodies. This study is based on a combined analysis through: Remote Sensing, Satellite Imagery, Geographic Information Systems (GIS), Field Studies and Geochemical Analysis. The results demonstrated that the lithological and structural characteristics of the geological formations, play a predominant role in the creation of this hydrogeological system, as well as, in the diversity of the physicochemical proprieties of water resources in the area, these geological formations are mainly composed by: Liassic limestone characterized by a circulation of fresh water (fresh springs), this Liassic limestone is put in contact with the Triassic saline clays through geological faults, which is in the origin of the creation of saline springs contaminating the upstream of the Oum-Er-Rabiaa river. In the light of the decisive results obtained a set of solutions have been proposed such as the diversion of saline springs, the purification in situ, and the development of a fish farming project. These solutions aim to guarantee a better quality of water resources of the area, to preserve agriculture and to valorize the saline water bodies with a sustainable development perspective.

PRODUCTIVITY OF SOME LAKES OF THE KOSH-AGACH DISTRICT OF THE REPUBLIC OF ALTAI

The Republic of Altai has a large length of watercourses and significant areas of lakes of fishery importance. The collection of materials was carried out in the field season of 2018 on the lakes: Uch-Kol (Three Lakes), Kamyshevoye and Lake without a name, located within the borders of Kosh-Agach district of the Altai Republic. Research has covered the entire water area. In the course of the research it was noted that Lake Uch-Kol consists of three successive basins with a total area of 7.9 hectares. The upper lake basin has an area of 5.5 hectares. The average lake basin has an area of 1.8 hectares. The lower lake basin has an area of 0.6 ha. Higher aquatic vegetation in the pond is missing. Lake zooplankton is represented by one species of Cladocera and two species of Copepoda. Lake Zoobenthos Uch-Kol is represented by a representative of the r. Gammarus. The area of Kamyshevoye Lake is 7.4 ha. The pond has a slightly elongated shape from west to east. In the zooplankton of the reservoir of mass development, branchy and rotifers reach. Chironomid larvae and caddisfruits dominate in the structure of zoobenthos. The area of the lake without a name is 29.4 hectares. The reservoir has a form elongated from the northeast to the southwest. In terms of numbers and biomass, Copepoda copepads are the dominant group in zooplankton. The dominant position in the zoobenthos composition is occupied by caddis flies and gammarids. All studied water bodies have low biological productivity. Phytoplankton is represented mainly by diatoms and green algae. The ichthyological fauna of Lake Uch-Kol and Lake Kamyshevoye is represented by an oligoid type of ichthyocenosis. The ichthyological fauna in the Lake without a name is missing.

Regional trends in eutrophication across the Loire river basin during the 20th century based on multi-proxy paleolimnological reconstructions

Excessive inputs of sediment and acceleration of primary production have been observed worldwide in a large number of water bodies. Human-environment interactions were recognized as one of the main drivers of this evolution during the 20th century with the occurrence of major landscape changes and a greater use of agricultural inputs.In this study, we used paleo-production proxies such as chlorophyll-a, organic matter properties (TOC and TN concentrations, δ13C and δ15N) measured in sediment cores dated with fallout 210Pbex and 137Cs activities for reconstructing changes in accumulation rates and sources of organic matter during the recent period of agricultural intensification (1920–2020). In order to record these changes at the regional scale, sediment cores were collected at the outlet of several headwater catchments (n = 9), covering a wide range of land covers / land uses across the Loire River basin (117,000 km²), France.The rates of sedimentary organic matter deposition in the studied water bodies accelerated from 1950 onwards (+48 %). Between 1950 and 1970, the signature of sedimentary organic matter indicates a dominant contribution of soil-derived inputs. This period corresponds to major landscape modifications across the basin (land consolidation, stream re-design, implementation of tile drains) driving a general acceleration of erosion rates. Then, from 1960 onwards, chlorophyll-a and C/N proxies indicate an increase in primary production coupled with a decrease of terrigenous supply in agricultural catchments. These proxies were strongly correlated to the agricultural inputs during the 1955–1990 period (e.g., r = 0.9 between chlorophyll-a content and N inputs), suggesting a progressive eutrophication of these reservoirs driven by increasing fertilizer use. During these 35 years, sedimentary organic matter deposition rates increased on average by 30 %. During the 1990s, despite a slight reduction in fertilizer use (−13 %), the paleo-production proxies (e.g. chlorophyll-a) still indicate a positive trend suggesting the contribution of another driving factor such as climate warming or again nutrient release from soils and sediments.In the absence of long term geochemical and sediment input monitoring, paleolimnological reconstructions provide a powerful tool to reconstruct past agricultural pressures in rural environments. This study illustrates the impact of intensive farming on water body siltation driven by varying sources of organic material during the 20th century. In addition, these results suggest that eutrophication processes of these reservoirs with contrasting land uses started during the 1960–1970 period and are still ongoing nowadays.

The Hydrochemistry and Recent Sediment Geochemistry of Small Lakes of Murmansk, Arctic Zone of Russia

This paper presents the first study of five small lakes located in the city of Murmansk. Field work was carried out during 2018–2019. Water samples were collected using a bathometer, while the sediments were sampled using an Ekman grab and Limnos gravity corer. It was found that the water of the studied lakes in Murmansk belong to the sodium group of the chloride class and to the calcium group of the hydrocarbonate class. Compared to the background level, elevated pH, concentrations of the main cations of alkali and alkaline-earth metals, N compounds, total dissolved solids, and heavy metals were found in the lakes, which indicate exposure to anthropogenic impacts. The sediments of the lakes, composed of organomineral and mineral silts, also have an elevated content of heavy metals compared to the background. The most significant excessive concentrations were found for V, Ni, Sb, Pb, Co, Cr, and W. Based on the calculated pollution load index and geoaccumulation index of the sediments, the studied water bodies in Murmansk can be classified as lakes with heavy and extremely heavy pollution levels. The primary pollution sources are emissions from the Murmansk thermal power plant, coal port, road and, rail transport.

Особенности биологии и промысла плотвы (Rutilus rutilus L.) в некоторых водоемах Республики Карелия

The article summarizes the results of long-term observations of the status of roach stocks in the main fishing waters of the Republic of Karelia (Lake Onega, Lake Ladoga, Vodlozerо and Topo-Pyaozerо reservoirs, Lake Syamozero). New data on its biology (distribution, linear and weight indicators, abundance, biomass) have been presented. There has been shown the dynamics of roach catch for a long-term period (1950–2017). It has been found that the fishing capacity of the represented roach populations corresponds to the production capabilities of its mature part and to the value obtained by biomass growth. The results of observations showed that in the studied water bodies the number and stocks of roach allow for greater volumes of catch than it is currently available and the total catch can be increased up to the calculated values of the allowable catch subject to rational fishing in the water bodies. Roach should be commercially caught at the age of 4+ years old. Given the interspecific contradictions of roach and bream, intensive fishing is recommended during the period of spawning in the straits, bays and mouths of rivers. For catching roach, it is necessary to use coastal-type fishing gear (trap nets, seines). The intensity of fishing and the increase in catches in reservoirs should be considered as mandatory measures in terms of biological reclamation in water bodies. When allocating catch quotas, the priority should be given to the most productive roach suppliers. The accompanying factor for the wide distribution of roach, along with other spring-spawning carp species (blue bream, bream), in our opinion, is warming of the climate in the region. In this regard, it is necessary to take measures to force catching the above fish species.

Экологическое состояние малых водоемов различного природоохранного статуса (Самарская область)

Currently, the conservation of the unique ecosystems of small water bodies located within cultural landscapes and/or in areas with limited nature protection status is of urgent issue. It is such hydrobiocenoses that are the most susceptible to increasing anthropogenic impact. Phytoplankton is a good indicator of the ecological situation in the reservoir. The aim of the work was to analyze the composition and structure of phytoplankton of some small urbanized lakes of Samara region with different levels of protection and degree of anthropogenic load. Here, this is the first time we present an analysis of the current ecological state of three small water bodies having various nature protection statuses: Lake Yaitskoe (53°10ꞌ85ꞌꞌN,50°17ꞌ46ꞌꞌE), the regional natural monument; Lake Gatnoe (53°14ꞌ93ꞌꞌN, 50°11ꞌ83ꞌꞌE), Samara region natural heritage site; and Lake Bolshoe Vasilievskoe (53°54ꞌ40ꞌꞌN, 49°53ꞌ24ꞌꞌE), the suburban lake located in the transition zone of the Middle Volga complex biosphere reserve (See Table 1). We collected samples for phytoplankton study and basic physical and chemical measurements in the growing season from 2013 to 2014 (See Table 2). We sampled the algae with a Ruttner bathometer. The material was fixed with 40% formalin solution. The cell count was carried out in the chamber “Uchinskaya” (Russia) with a volume of 0.01 ml. This chamber is a glass plate with low sides, the bottom of which is equipped with a special counting grid, optimized for counting plankton. Organisms are counted twice in 20 bands. Species identification of algae and counting of their cells were carried out on the microscope “BIOLAR PI” (limited liability company “Biolar”, Poland) with an increase of 600 times. To determine the species of algae, we used reference guides from the series “Determinants of freshwater algae of the USSR” and “Susswasserflora von Mitteleuropa”. The classification of Reynolds and co-authors was used to differentiate phytoplankton into functional groups. S1 -type (planktotrichete type) consisted of filamentous non-heterocyst forms of cyanoprokaryotes that previously belonged to genus Oscillatoria, M-type contained representatives of genus Microcystis, H1 -type contained representatives of genera Anabaena and Aphanizomenon. The similarity of the algae species composition of lakes was estimated with the Sorensen coefficient (Ks). The level of cenotic diversity and the degree of community alignment were assessed using Shannon (H) and Pielu (E) indices, respectively, taking into account the standard deviation. The dominant species were those whose number and biomass was 10% or more of the total value. The Simpson dominance index (S) was used to estimate the degree of dominance of individual species. Assessment of saprobity of waters was carried out by the method of Pantle and Bucc in the modification of Sladechek, using known indicator values of saprobity of individual species. The general state of ecosystems of the studied lakes was analyzed on the basis of the qualitative composition and quantitative development of phytoplankton from 2013 to 2014. In all lakes, the species richness of phytoplankton was quite high and contributed mainly by chlorophytes, diatoms and cyanoprokaryota species (See Table 3 and Fig. 1). Floristic analysis revealed signs of imbalance in lake ecosystems, probably caused by anthropogenic impact and/or lack of biogenic limitation (See Table 4). This situation is especially unfavorable for ecosystems of water bodies of protected nature areas. Ecological and geographical analysis did not reveal significant differences between the algal flora of the studied reservoirs (See Table 5). The level of similarity of the species composition of the studied reservoirs was quite high (See Table 6). Perhaps this was due not only to similar abiotic parameters of the environment, but also to a high level of identical anthropogenic load. Quantitative phytoplankton development was high in all water bodies, the highest one was observed in Lake Bolshoe Vasilievskoe, and the lowest in lake Gatnoe (See Fig. 3). According to average algal biomass over the study period, Lake Bolshoe Vasilievskoe corresponds to the hypertrophic state, while lakes Gatnoe and Yaitskoe are eutrophic. Phytoplankton species diversity and alignment were highest in lake Gatnoe, and smallest in lake Yaitskoe. According to saprobity, the studied water bodies were β-mezosaprobic which corresponds to the water quality class III. Analysis of the floristic composition, the ratio of taxonomic ranks, indicators of quantitative development and the structure of the dominant species complex revealed signs of an imbalance in ecosystems and the development of “oscillatory” disease in all studied lakes, regardless of their conservation status due to anthropogenic impact and lack of biogenic restriction. The paper contains 3 Figures, 6 Tables and 38 References. The Authors declare no conflict of interest.

Spatial Differences in the Chemical Composition of Surface Water in the Hornsund Fjord Area: A Statistical Analysis with A Focus on Local Pollution Sources

Surface catchments in Svalbard are sensitive to external pollution, and yet what is frequently considered external contamination may originate from local sources and natural processes. In this work, we analyze the chemical composition of surface waters in the catchments surrounding the Polish Polar Station in Svalbard, Hornsund fjord area. We have pooled unpublished and already published data describing surface water composition in 2010, related to its pH, electrical conductivity (EC), metals and metalloids, total organic carbon (TOC) and selected organic compound concentrations, including persistent organic pollutants (POPs) and surfactants. These data were statistically analyzed for spatial differences, using Kruskal–Wallis ANOVA and principal component analysis (PCA), with distance from the station in the PCA approximating local human activity impact. The geological composition of the substratum was found to be a strong determinant of metal and metalloid concentrations, sufficient to explain significant differences between the studied water bodies, except for the concentration of Cr. The past and present human activity in the area may have contributed also to some of the polycyclic aromatic hydrocarbons (PAHs), although only in the case of naphthalene can such an effect be confirmed by an inverse correlation with distance from the station. Other likely factors contributing to the chemical concentrations in the local waters are marine influence, long-range pollution transport and release from past deposition in the environment.