Types Of Water Bodies Research Articles

Advances in Limnogeology: The lake‐basin‐type model revisited 25 years after…anomalies, conundrums and upgrades

AbstractThe lake‐basin‐type model classified the stratigraphic record of ancient lake systems according to rates of potential accommodation relative to sediment + water supply. The model convolved all modes and paths of water supply (direct fall, surficial, subsurface) with amounts and types of sediment supply (clastic, biogenic, chemical) into a single basin‐filling volume term (sediment + water); its major strength was its widespread applicability. This was supported by subsequent investigations confirming the utility of this approach, but it also revealed some important limitations due to simplifications in the original model. The model has been expanded here to address all inland waters (lakes, ponds, wetlands, playas) as well as adding two major subdivisions of the sediment + water term: (1) water supply paths and (2) the volume of water supply relative to sediment supply. Water supply flow paths in the subsurface are subdivided into ‘throughflow’, ‘recharge’ and ‘discharge’. Each of these groundwater hydrology states can be defined quite precisely by the ratio of net outflow to inflow, from persistently open to consistently closed. These paths can be deciphered using stable carbonate and oxygen isotope composition of primary lacustrine limestones, detailed sedimentology, stratigraphy, palaeontology and mineralogy. Distinguishing water supply paths provides additional insights into playa systems and the occurrence and character of evaporites and carbonates. The volume ratio of water to sediment supply most directly influences the water depths of lakes, ponds and wetlands, which affect water body hydrodynamics and ecosystem behaviour as well as the details of stratal stacking and depositional sequences. It helps fine‐tune estimates of the distribution of sediment texture, bedding, composition and organic matter content. The aim of this contribution is to address questions about the fundamental types of inland water bodies and to explain the new lake‐basin subtypes and provide examples that illustrate their potential to enable higher‐resolution, robust analysis of inland water systems and their stratigraphic records.

An effective transformer based on dual attention fusion for underwater image enhancement

Underwater images suffer from color shift, low contrast, and blurred details as a result of the absorption and scattering of light in the water. Degraded quality images can significantly interfere with underwater vision tasks. The existing data-driven based underwater image enhancement methods fail to sufficiently consider the impact related to the inconsistent attenuation of spatial areas and the degradation of color channel information. In addition, the dataset used for model training is small in scale and monotonous in the scene. Therefore, our approach solves the problem from two aspects of the network architecture design and the training dataset. We proposed a fusion attention block that integrate the non-local modeling ability of the Swin Transformer block into the local modeling ability of the residual convolution layer. Importantly, it can adaptively fuse non-local and local features carrying channel attention. Moreover, we synthesize underwater images with multiple water body types and different degradations using the underwater imaging model and adjusting the degradation parameters. There are also perceptual loss functions introduced to improve image vision. Experiments on synthetic and real-world underwater images have shown that our method is superior. Thus, our network is suitable for practical applications.

A novel hierarchical approach to insight to spectral characteristics in surface water of karst wetlands and estimate its non-optically active parameters using field hyperspectral data

Wetlands cover only around 6 % of the Earth's land surface, and are recognized as one of the three major ecosystems, alongside forests and oceans. The ecological structure and function of karst wetlands are unique due to the influence of geologic structure. At present, the unclear spectral morphology of surface water in karst wetlands poses a significant challenge in remote sensing estimation of non-optically active water quality parameters (NAWQPs). This study proposed a novel multi-scale spectral morphology feature extraction (MSFE) method to insight to spectral characteristics in surface water of karst wetlands, and further screen the sensitive features of NAWQPs. Then we constructed three remote sensing inversion strategies for NAWQPs (TN, TP, NH3_N, DO), including direct estimation, indirect estimation, and auxiliary estimation. Finally, we constructed a novel pH-based hierarchical analysis framework (pH_HA) to thoroughly explore the influence of alkalinity-biased characteristics of karst water on the spectral domain of NAWQPs and its estimation accuracy using in-situ hyperspectral data, respectively. We found that the spectral characteristics of karst waters at the first reflectance peak (580 nm) differed significantly from other water body types. The MSFE successfully captured the sensitive spectral domains for NAWQPs, and focused on between 500 and 600 nm and 900–960 nm. The sensitive features captured by MSFE improved estimation accuracy of NAWQPs (R2 >0.9). Direct estimation presented more stable performance compared to the auxiliary estimation (average RMSE of 0.366 mg/L), and the auxiliary estimation model further improved the retrieval accuracy of TN compared to direct estimation model (R2 increasing from 0.43 to 0.56). The novel hierarchical framework clearly revealed the notable changes in the sensitive spectral domains of NAWQPs under different pH values, and enabled more precise determination of spectral subdomains of NAWQPs, and identified the optimal spectral features. The pH_HA framework effectively improved the estimation accuracy of NAWQPs (R2 increased from 0.514 to over 0.9), and the estimation accuracies (R2) of four NAWQPs were all more than 0.9 when the pH value was over 8.5. Our works provide an effective approach for monitoring water quality in karst wetlands.

Variations in the Odonata Assemblages: How Do the Dry Season and Water Bodies Influence Them?

Diverse abiotic and biotic factors drive the ecological variation of communities across spatial and temporal dimensions. Within the Amazonian landscape, various freshwater environments exhibit distinct physicochemical characteristics. Thus, our study delved into the fluctuations of Odonata assemblages amidst distinct water bodies within Amazonia, encompassing two distinct climatic seasons. Comparative analysis was conducted on Odonata species diversity and assemblage composition across a blackwater pond, a lake, and a stream, spanning the initiation and culmination of the dry season in the southwestern Amazon region in Peru. Our methodology involved capturing adult Odonata using entomological nets on three separate occasions between 11:00 and 14:00h for each water body in May (beginning of the dry season) and October (end of the dry season) of 2018. We also evaluated the influence of temperature, precipitation, and percent cloud cover on the abundance and richness of adult Odonata. Species richness and composition differed among the three water bodies in both periods of the dry season. No effect of the dry season periods on species richness and abundance was observed. However, except in the oxbow lake, the more abundant species were substituted to the end of the dry season. Our study highlights the influence of water body types on Odonata species diversity and composition. The effects of the sampling period during the dry season may not be immediately apparent in conventional diversity metrics, such as species richness and abundance. Instead, its effects manifest predominantly in the relative abundance of the species that compose these assemblages.

Browning from headwaters to coastal areas in the boreal region: Trends and drivers

Browning of freshwaters, mainly caused by increased terrestrial organic carbon loading, has been widely studied during the last decades. However, there are still uncertainties regarding both the extent of browning in different aquatic ecosystems and the actual importance of different driving forces and mechanisms. To refine understanding of the extent and causes of browning and its temporal variation, we gathered a comprehensive dataset including 746 Finnish water quality monitoring stations representing various waterbody types: streams, rivers, lakes, and coastal waters. Monotonic trend analyses revealed that TOC concentrations increased in all waterbody types during the study period from 1990 to 2020, whereas non-linear trends indicated that upward trends in TOC concentrations have substantially decreased since the mid-2000s. However, despite the upward trends levelling off, non-linear analyses also indicated decreases in TOC concentrations at only a few stations. As a result, the TOC contents of the majority of Finnish waterbody types in 2020 were at a higher level than in 1990. To examine the driving forces of increasing TOC concentrations, we selected 100 riverine catchments and linked the detected trends to 24 different drivers, including both hydrometeorological and catchment characteristics. The increased TOC concentrations in surface waters could be connected to diverse human impacts: hydrometeorological variables impacted by climate change, decreased acidic deposition, and land use in terms of peatland drainage. The importance of increased temperatures was emphasized, and its role as a driver of increased leaching of organic carbon in the forthcoming years is expected to grow with climate change.

Actual diversity and distribution of charal algae of the genus <i>Nitella</i> C.Agardh (Charophyta) in Ukraine)

The results of the analysis of literature and original data on the species diversity and distribution patterns of algae of the genus Nitella C.Agardh (Charophyta, Charales) in Ukraine are presented. Now, the diversity of the genus Nitella in Ukraine is represented by 9 species out of 13, known in the Europe flora of Charales, namely: Nitella capillaris (Krock.) J.Groves et Bull.-Webst., N. confervacea (Bréb.) A.Braun ex Leonh., N. gracilis (Sm.) C.Agardh, N. flexilis (L.) C.Agardh, N. mucronata (A.Braun) Miq., N. opaca (C.Agardh ex Bruz.) C.Agardh, N. syncarpa (Thuill.) Chev., N. tenuissima (Desv.) Kütz. and N. translucens (Persoon) C.Agardh. An annotated list of Ukrainian species in Ukraine. A total of 78 locations have been registered, including historical, lost, and modern ones. Most of them were found within the Pripyat-Desnianska (PpDSAP) (50) and Serednyodniprovska (SDpAP) (21), much less  within the Dnieper-Black Sea (DpAp) (3) and Carpathian-Danube (CpDnAP) (4) algofloristic subprovinces. It is suggested that main limiting factors influencing on diversity and distribution patterns of the Nitella species in Ukraine are the type of waterbodies, temperature, a degree of minimalization as well as chemical main ionic composition of water and active reaction (pH) of water.

Aquatic Insects (Ephemeroptera, Plecoptera and Trichoptera) Metric as an Important Tool in Water Quality Assessment in Hilly and Mountain Streams

The aim of the study was to test the significance of the EPT index in the water quality assessment of three types of water bodies in hilly and mountainous region of Serbia. The aquatic macroinvertebrate community was dominated by the group of insects, of which 95 taxa represent the EPT group. We compared the obtained values of biological indices used for the assessment of water quality according to the national legislation with the overall status assessment represented by the ecological quality classes (EQC). The results of the Spearman correlation test showed a negative correlation of EQC with the EPT index, BMWP score, H′, total number of taxa and number of sensitive taxa, while a positive correlation was observed for the values of SI and Tubificinae %. The values of EQC and biological indices were subjected to principal component analysis (PCA). The results showed that the parameters that contributed most to the differences were the EPT index, the BMWP score and the number of sensitive taxa. The results indicate that the EPT index is an excellent indicator of changes in water quality and an important tool for the ecological categorization of water bodies in mountain regions.

Application of bathymetry in water bodies in urban areas of the five Brazilian regions

Application of bathymetry in water bodies in urban areas of the five Brazilian regions

Habitat Preference of Lesser Whistling Ducks (Dendrocygna javanica) in Selected Wetlands within Colombo Ramsar Wetland City

Lesser Whistling Ducks (LWD) (Dendrocygna javanica) mostly occur in flocks and inhabit lakes, ponds and marshes within freshwater wetlands. They feed mainly on plants taken from water (seed, shoots, tuber and leaves), vertebrates (fishes) and invertebrates (mollusks and worms). In this study, habitat preference of LWD in five selected wetlands in Colombo Ramsar Wetland City (CRWC); Beddagana Wetland Park (BWP), Diyasaru Park (DP), Heen Ela Marsh (HEM), Thalangama Marsh (TM) and Kimbulawala Wetland (KW) was studied from May 2021 to April 2022 as wetlands in urban areas act as the last resort for many resident and migratory bird species and play a major role in the assemblage and conservation of water birds. Habitats present in the selected wetlands were categorized as open water body, floating vegetation, trees, grassland, paddy field, shrubs, bare land. Percentage cover of each habitat type at each sampling site were estimated using quadrat method. LWD were surveyed using line transects of 100m in length, laid in each selected study site to cover representative habitats and observations were made up to 30m towards either side of each transect. Sampling was done in three time slots of the day, morning, mid-day and evening. Floating vegetation, open water body and grassland were the preferred habitat types of D. javanica in BWP, DP, HEM and TM. LWD were not recorded in KW. Floating vegetation (54.97%) was the most preferred habitat by LWD in each study site followed by open water body (24.70%) and grassland (15.82%) habitat types. Eicchornia crassipes (Common water hyacinth) and Salvinia molesta (Giant salvinia) were their most preferred floating vegetation type. Higher abundance of LWD was recorded in TM (83.22%) followed by DP (9.17%), BWP (4.16%) and HEM (3.45%). TM which had higher abundance of LWD had higher floating vegetation coverage (28%) and was rich with E. crassipes and S. molesta. Present study revealed that, LWD mostly used E. crassipes and S. molesta as their main foraging and resting sites. Management of invasive alien species have been undertaken in Colombo wetlands and as E. crassipes and S. molesta are alien species they are currently being removed. Therefore, outright removal of E. crassipes and S. molesta may not be suitable and a monitored removal program that will conserve this habitat type should be implemented in order to conserve the habitats preferred by LWD in CRWC. 
 Keywords: Lesser whistling ducks, Wetlands, Habitat preference

Distribution characteristics of reactive silicon in six water bodies in the Yangtze River Basin in China

Terrestrial silicon (Si) from biogeochemically weathered rocks and soils into oceans must pass through several water bodies, resulting in some Si immobilized. Hence, the knowledge on Si distribution characteristics in different water bodies at a basin scale is helpful to understand Si immobilization. A total of 65 surface sediments and corresponding overlying water samples were sampled from six water bodies (Dianchi Lake, DL; Dadu River, DR; Tuojiang River, TR; Honghu Lake, HL; Donghu Lake, DhL; Taihu Lake, TL) in the Yangtze River Basin of China, total dissolved Si (TDSi) in overlying water and exchangeable Si (Ex-Si), active non-biogenic Si (NBSi), and total acid dissolved Si (TADSi) in sediments were analyzed. Water chemical parameters (pH, EC, and TDP) and sediment components (LOI, TN, TP, and TADFe) showed that the water environment characteristics of six water bodies differed. TDSi differed among regions and between lakes and rivers, significantly higher in water bodies in the upper reaches and rivers than the middle or lower reaches and lakes (p < 0.05), respectively. Ex-Si in sediments in the upper reaches was significantly higher than in the middle or lower reaches (p < 0.05), except for DhL, whose Ex-Si was the highest. Mean TADSi and active NBSi were significantly higher in lakes than rivers (p < 0.05). Oxidation of sediments significantly increased TDSi in overlying water and active NBSi in sediments (p < 0.01). Si forms in six water bodies significantly depended on components of the sediments (e.g. active Ca2+, Mg2+, Fe, and Al3+) and water chemical parameters (p < 0.05). Our results suggest that immobilization of Si in water bodies in the Yangtze River Basin depends on the types of water bodies and sediments, lakes and Fe–Al dominated sediments have a high potential to immobilize Si, but anthropogenic interference should not be ignored.

Balancing between predation risk and food by boreal breeding ducks.

Wetlands belong to the globally most threatened habitats, and organisms depending on them are of conservation concern. Wetland destruction and quality loss may affect negatively also boreal breeding ducks in which habitat selection often needs balancing between important determinants of habitat suitability. In Finland duck population trajectories are habitat-specific, while the reasons behind are poorly understood. In this research, we studied the balance of nest predation risk and invertebrate food abundance in boreal breeding ducks in Finland at 45 lakes and ponds in 2017 and 2018. We surveyed duck pairs and broods from these and 18 additional water bodies. We evaluated nest predation by monitoring artificial nests with camera traps over a 7-day exposure period and sampled invertebrates from water bodies using emergence and activity traps. Camera trap results indicate that predation risk was higher in the water bodies surrounded by agricultural land than in forestland. Ponds (seasonal, beaver, and man-made) had lower nest predation risk, and they were also more invertebrate-rich than permanent lakes. In addition, artificial nests further away from water bodies had higher survival than shoreline nests. Habitat use of duck pairs was not associated with invertebrate food, but duck broods preferred habitats rich in food. High nest predation pressure in shorelines of especially agricultural landscapes may contribute to the declining population trends of ducks in Finland. Controlling predators could be an important conservation action to improve duck breeding success. This research underlines the benefits of the availability of different water body types for breeding ducks. There is an urgent need to pay attention to protecting seasonal ponds, while the lack of flooded waters may be mitigated by favouring beavers or creating man-made ponds.

Characteristics of Groundwater Microbial Community Composition and Environmental Response in the Yimuquan Aquifer, North China Plain

To explore the intricate interrelationship between groundwater microbial communities and hydrochemical characteristics in the Mancheng District, Baoding City, samples from karst groundwater and porous groundwater were collected. Hydrochemical analysis and the 16s RNA gene V4-V5 region sequencing method were used to detail the water environmental characteristics and microbial community distribution pattern in the study area. The hydrochemical results reveal notable differences in major ion contents and other hydrochemical indices between karst water and porous water. Microbial community analysis demonstrates that Proteobacteria, Actinobacteria, and Firmicutes are the dominant taxa in both types of water bodies, albeit with significant variations in their proportions across distinct water bodies. The observed disparities in microbial communities between karst water and porous water underscore the influence of environmental factors such as ion concentration and pH on microbial distribution. Redundancy Analysis (RDA) indicates notable associations between microbial community composition and environmental factors in both types of groundwater environments. Studying the distribution pattern of microbial communities and the connection with environmental factors in two types of groundwater lays a crucial foundation for interpreting the functional roles of microbes in groundwater ecosystems.

Stable oxygen isotopes of crocodilian tooth enamel allow tracking Plio-Pleistocene evolution of freshwater environments and climate in the Shungura Formation (Turkana Depression, Ethiopia)

Abstract. This study adopts a new approach describing palaeohydrology and palaeoclimates based on the interpretation of stable oxygen isotopes (δ18Op) recorded in fossil crocodilian teeth. They represent an archive of prime interest for tracking freshwater palaeoenvironmental change, applicable to many palaeontological localities in the world: crocodilian teeth are abundant in continental basins and have been widely distributed since their diversification during the Mesozoic; the enamel phosphate is resistant to diagenesis and retains its original isotopic composition over geological timescales; and their δ18Op mainly relies on that of the crocodilian's home waterbody (δ18Ow), which in turn reflects waterbody types, regional climate, and evaporation conditions. This study presents the first application of this theoretical interpretative model to the Shungura Formation (Lower Omo Valley, Ethiopia), a key witness of the important environmental change in eastern Africa during the Plio-Pleistocene that impacted the evolution of regional faunas, including humans. In this complex and variable environmental context, the δ18Op of coexisting crocodilians allows for the fingerprinting of the diversity of aquatic environments they had access to at a local scale. This study sheds light on two important results: the δ18Op of crocodilian teeth (1) indicates stable aquatic environments in the northern Turkana Depression from 2.97 to ca. 2.57 Ma but a decline in local waterbodies diversity after 2.32 Ma, suggesting increasing aridity, and (2) shows, like previous geochemical studies on palaeosols and bivalves in the area, a significant increase in δ18Ow from 2.97 to ca. 1.14 Ma, likely due to the shifting air stream convergence zones between the West African and Indian Summer Monsoons and/or reduced rainfall over the Ethiopian Highlands.

Leeches (Annelida, Hirudinea) Fauna of Nakhchivan Autonomous Republic

The fauna of the leeches of Nakhchivan Autonomous Republic is represented by 10 species belonging to 9 genera, 5 families, 2 orders and one class. According to zoogeographical affiliation, leech species belong to 4 faunistic complexes. In the benthic infauna of various types of water bodies, glossyphonides predominate in the frequency of occurrence and abundance of individuals. An extremely rare medical leech (Hirudo medicinalis) is the only practically useful representative of the girudofauna. Functional significance of other species in biocenoses is low. The article also presents data on morphology, body sizes, objects of finding and biotopes of leeches of fauna of Nakhchivan.

Source and genesis of Ca-Cl type brines in Qaidam Basin, Qinghai-Tibetan Plateau: evidence from hydrochemistry as well as B and Li isotopes

Ca-Cl brine is a highly mineralized special water body occurring in oceanic ridges or basins. The deep part of the western Qaidam Basin is rich in Ca-Cl brine, which is essential for the formation of (MgSO4-deficient) potash deposits. Previous studies on this type of brine in the Qaidam Basin focused on its source tracing, but different carriers led to different conclusions. Moreover, the genesis of Ca-Cl brines in inland basins still remains unclear. In essence, a solid understanding of the relatively abundant Ca sources for the formation of Ca-Cl brines in inland basins has not been reached. In addition, a metallogenic model for this type of brine has not yet been established. Through hydrochemical analysis as well as Band Li isotope tracing, this study clarified that the main elements (Na and Cl) in these Ca-Cl brines mainly originated from the dissolution of existing evaporites in the inner basin. Further, trace elements in Ca-Cl brines (such as Band Li) mainly originated from lixiviation; atmospheric rainfall infiltrated and interacted with ore-rich mother rocks along the basin-margin fracture system under suitable temperature-pressure conditions; alternatively, they may have originated from mixing with magmatic hydrothermal fluids. This study showed that Ca-Cl brines in the western part of the Qaidam Basin have a typical “binary structure” in terms of their sources. In addition, the sources of Ca in Ca-Cl brines were further discussed based on B and Li isotope data, thus exploring a new genesis of Ca-Cl brines in inland basins. Finally, by integrating the above findings, an ore-forming model of this type of water body in the western part of the Qaidam Basin is proposed. This study is valuable for understanding the genesis mechanism of Ca-Cl brines in inland basins, and also has practical significance for the prediction, exploration, and evaluation of this type of brine resource.

Distribution of Algae According to Habitat Preferences in Saline Coastal Reservoirs of Pryazov National Natural Park (Ukraine)

This study focused on the distribution of algae in the saline coastal water bodies of Pryazov National Nature Park according to their habitat preferences. This research revealed that aquatic species form the basis of the algal flora. Among these, diatoms were predominant in terms of species richness and frequency of occurrence. In the lake-type estuaries and ephemeral water bodies, an increased number of amphibious species were found, which can be attributed to the fluctuating water level. Among the amphibious species, &lt;i&gt;Cyanoprokaryota&lt;/i&gt; representatives dominate. Hierarchical clustering of the water bodies demonstrated a connection between the species composition of algae and the type of water body, which is consistent with their genesis and transformation.

Возраст и рост обыкновенного судака Sander lucioperca в разнотипных водоемах юга Западной Сибири

The age and growth of fish are the most important characteristics underlying the assessment of the state of fish stocks and the forecasting of future catches. The pike-perch Sander lucioperca (Linnaeus, 1758) is an alien fish species in Western Siberia. It was first introduced into the Ob basin in 1956. The introduction of this species into the Novosibirsk reservoir was carried out in 1959-1964, and into Lake Chany in 1964-1966. Currently, pike-perch is spread throughout the Ob basin and is an important fishery target. This study summarizes long-term data from the Novosibirsk branch of Russian Federal Research Institute of Fisheries and Oceanography ("VNIRO") about the growth of different-aged individuals of the pike-perch, collected during monitoring of aquatic biological resources in the Novosibirsk reservoir (54°20' N, 81°57'E) and Lake Chany (54°55'N, 77°31'E) over the last 10 years (2013-2022). These water bodies are of different types: the Novosibirsk reservoir was formed on the Ob River, the maximum depth reaches 25 m, the average depth is 8 m. The area of the reservoir is 1.07 thousand km^. Lake Chany is located in the Ob-Irtysh interfluve, drainless, filled due to the runoff of the Kargat and Chulym rivers, atmospheric precipitation and groundwater. The maximum depth is up to 8 m, average depth is 2 m. The area of the lake fluctuates greatly from year to year depending on the water level, in the long-term aspect it has tends to decrease, currently amounting to about 2 thousand km. The lake water has increased mineralization in most of the reaches. Fish collection for analysis of size characteristics is carried out annually from commercial catches. The total volume of material for this study was 2953 individuals from Lake Chany and 1102 individuals from the Novosibirsk reservoir. As a result of this work, it was found that in commercial catches in different types of water bodies in the south of Western Siberia, pike-perch has been known at the age of up to 14+ years over the last 10 years. In Lake Chany, there were mostly individuals of age groups 2+-4+, and in the Novosibirsk Reservoir - 3+-6+ (See Fig. 1). The pike-perch size of the same age from commercial catches varies greatly from one year to the next in Lake Chany, and in the Novosibirsk reservoir (See Fig. 2). It confirms the data on significant variability in growth rates of this species and indicating the need for a cautious approach to comparing the length and weight of pike perch in different observation periods. On average, over the last decade, pike-perch in Lake Chany is characterized by a slightly shorter standard length and greater weight than in the Novosibirsk Reservoir, however, the differences reach statistical significance (p &lt; 0.001) only when comparing fish aged 2+ by standard length (See Fig. 3). The analysis of the relationship between the growth rate of pike-perch and environmental temperature showed that the absolute increase per year of standard length and weight of younger age groups fish in the Novosibirsk Reservoir has a statistically significant positive correlation with the temperature in April (r = 0.6110.775), and in Lake Chany - in May (r = 0.633-0.737) (See Tables 1, 2). Considering that the average April temperature in the area of the Novosibirsk reservoir is 1.9°C higher than in the area of Lake Chany, probably, in the latter, juvenile pike-perch begins to actively feeding a little later. It may explain the smaller sizes of pike-perch of younger age groups in Lake Chany compared to the Novosibirsk reservoir. The article contains 4 Figures, 2 Tables and 28 References. The authors express their gratitude to all colleagues - employees of the Novosibirsk Branch of "VNIRO", who over in different years took part in collecting the material. The Authors declare no conflict of interest.

Diversity of planktonic pro- and microeukaryotes in water bodies of the Volga-Don basin during the period of cyanobacterial bloom according to metabarcoding data

The first data on the phylogenetic diversity of planktonic communities of pro- and microeukaryotes in different types of water bodies of the Volga-Don basin during the period of cyanobacterial bloom are presented. Aphanizomenon flos-aquae/Dolichospermum flos-aquae blooms were found mainly in the Kuibyshev Reservoir; Planktothrix agardhii bloom was observed in floodplain lakes of the majority of investigated rivers. Bloom of Raphidiopsis raciborskii was found in a lake on the Volga River terrace, and in a pond in the floodplain of the Samara River Anabaenopsis dominated anong Cyanobacteria. Among heterotrophic prokaryotes, Proteobacteria, Bacteroidota, Verrucomicrobiota, Planctomycetota and Actinobacteriota predominate in the number of sequences, and among protists - Ciliophora, Gyrista (mainly Chrysophyceae), Cryptista and Myzozoa. During the period of cyanobacterial bloom, the contributions of Proteobacteria (especially, Burkholderiales and Pseudomonadales) and Actinobacteriota slightly decrease, while Myzozoa, on the contrary, increase. Monodominant blooms of various species of cyanobacteria significantly change the composition and structure of microbial communities, both at the OTUs and higher taxa levels. The plankton of the pond with Anabaenopsis bloom is most peculiar. Communities with blooms of P. agardhii, R. raciborskii and A. flos-aquae/D. flos-aquae are more similar to each other.

Refined Water-Body Types Mapping Using a Water-Scene Enhancement Deep Models by Fusing Optical and SAR Images

Refined Water-Body Types Mapping Using a Water-Scene Enhancement Deep Models by Fusing Optical and SAR Images

Distribution pattern of &lt;i&gt;Nitellopsis obtusa&lt;/i&gt; (Desv.) J.Groves (&lt;i&gt;Charophyta&lt;/i&gt;, &lt;i&gt;Charales&lt;/i&gt;) in Ukraine

The article presents the results of the analysis of literature and original data on Nitellopsis obtusa (Desv.) J.Groves (Charophyta, Charales) included in Red Data Book of Ukraine and peculiarities of its distribution in Ukraine. This relict species is also regionally red-listed in its native Eurasian range within temperate and subtropical latitudes from Portugal to Japan but invasive in North America, in the Great Lakes region, because of an accidental introduction in 20th century. In Central and Eastern Europe N. obtusa is a rather common species but it happens everywhere rather sporadically. Its distribution is limited by such factors as a type of water body, total mineralization, ionic composition of water and pH. Totally 26 localities of N. obtusa have been recorded, including historical, lost, and existing ones. A list of localities, and a map of the distribution of this species in Ukraine have been compiled and analyzed. All of them were found within the Pripyat-Desna, Middle Dnieper, Dnieper-Black Sea algofloristic subprovinces. However, the characteristic of their location confirms the trend of distribution of N. obtusa in Ukraine only in the valleys of large rivers, which is most likely due to the absence of large lakes with stable hydrological and hydrochemical regimes, as well as ecological and biological features of the species.