Search Results (28)

Reliable biological datasets, especially those integrating biotic indices such as the Saprobic Index, are scarce, limiting machine and deep learning applications in aquatic ecosystem assessments. This study evaluates Conditional Tabular Generative Adversarial Networks (CTGANs) for generating synthetic datasets that combine physico-chemical parameters with a biological index (Saprobic Index) from multiple monitoring stations in the lower Danube River. Beyond univariate distributional agreement, we assess whether ecologically meaningful multivariate relationships are preserved in the synthetic tables. To support this, we propose an ecology-oriented validation workflow that combines distributional tests with correlation structure and clustering diagnostics across stations. Real monitoring datasets were statistically modelled and recreated using CTGANs, then qualitatively assessed for realism. Comparisons between synthetic and real data employed box plots, Wilcoxon rank-sum tests, correlation matrices, and K-means clustering across stations. Stable variables, including pH, total dissolved solids, and chemical oxygen demand, were well replicated, showing no significant distributional differences (p > 0.05). Conversely, dynamic parameters such as dissolved oxygen, total nitrogen, and suspended solids exhibited notable discrepancies (p < 0.05). Correlation analyses indicated that several strong associations present in the observed data (e.g., total nitrogen–nitrate and total nitrogen–electrical conductivity) were substantially weaker in the synthetic dataset. Overall, a CTGAN can reproduce several marginal patterns but may fail to preserve key ecological linkages, which constrains its use in ecological relationship-dependent inference. While promising for exploratory modelling and general trend analysis, synthetic data should be applied cautiously for studies involving seasonally influenced, biologically significant parameters. Full article

The Volga is the largest river in Europe and its headwaters comprise reference or least disturbed conditions. In the headwaters of the Volga (445 km) upstream of Tver, 27 diatom samples (18 from the Volga and nine from selected tributaries) were collected in shallow water along the banks from different habitats, wherefrom 270 taxa (244 pennate and 26 centric) were identified. Most benthic taxa were found within Naviculaceae (40 taxa), Fragilariaceae (29 taxa), Bacillariaceae (27 taxa), Achnanthaceae (23 taxa), Gomphonemataceae (19 taxa), Cymbellaceae (17 taxa), and 16 taxa belong to the Amphora-complex. Species richness in the Volga and its tributaries was comparable; the mean value was 46 in the Volga and 50 in the tributaries. Regarding the saprobic index, the source region (reach R1) was characterized by a large proportion of xeno- and oligo-saprobic species, with the proportion of oligo-beta and beta-meso-saprobic species increasing along the continuum. This study provides a first comprehensive checklist of benthic diatoms for the Volga headwaters and analyzes longitudinal changes as well as the interplay between abiotic parameters and the diatom community in the headwaters of the Volga. Full article

Human activities in the Apuseni Mountains region, Romania, especially in the Roșia Montană mining area, have significantly impacted water quality in the Arieș River tributaries. This study assessed the main physico-chemical and salinity parameters, along with the contents of trace elements (As, Cd, Co, Cr, Cu, Fe, Mn, and Ni) dissolved in water, as well as in the Abrud, Ștefanca, Valea Seșii, and Sârtaș rivers, the main tributaries of the Arieș River. Maximum concentrations of trace elements were observed in Valea Seșii (e.g., Zn up to 716 µg/L, Fe up to 562 µg/L), while Abrud and Sartăș showed moderate contamination. Diatom analysis revealed a high prevalence of Achnanthidium minutissimum and Planothidium lanceolatum, with teratological forms of A. minutissimum being the most frequent, indicating stress from pollutants. Saprobic index values ranged from 1.21 to 1.91, reflecting water quality from good to moderately impacted. The integration of chemical and biological data highlights the cumulative effects of mining and agricultural activities, demonstrating the utility of combined monitoring for effective freshwater management. Our results showed that numerous diatom taxa are currently present in samples collected from various watercourses within the Aries River basin, reflecting both the biological diversity and the variable influence of environmental factors on aquatic communities. Full article

Springs are unique ecosystems found in lowland areas. In urban environments, these springs often have niches that are heavily transformed by human activity. In this study, we identified and compared the taxonomic diversity of diatom communities across various microhabitats—epilithon, epipelon, epipsammon, epibryon, and epixylon—within altered lowland urban springs. Our results revealed differences in diatom communities among the microhabitats, with the highest species richness observed in the epibryon. Notably, the presence of extremely rare species such as Amphora eximia, Caloneis aerophila, and Stauroneis muriella suggest that, even under urban conditions, springs continue to serve a refugial function for diatom diversity. These findings underscore the important role of urban springs in maintaining diatom diversity despite high anthropogenic pressure. We also assessed the ecological status of the springs using the Polish Multimetric Diatom Index (IO), which incorporates indicators of trophy, saprobity, and the abundance of reference species. All studied springs were classified as having very good ecological status. Full article

Mayfly nymphs are reliable indicators of aquatic habitat quality, and whilst their presence and relative abundance are often used in bioassessment schemes, it is important to recognise that these attributes are affected by the sampling method employed. To test these effects, we sampled stream habitats for mayflies using two commonly used techniques in a standardised setup: aquatic sweep nets and manual collection from stones. These methods resulted in different success rates in detecting certain taxa depending on their biological traits (preferred microhabitat and locomotion type). Whilst species lists generally overlapped between the two methods, they yielded different values of total abundance, taxon richness, Shannon–Wiener’s diversity index, assemblage saprobic index, and general community structure. These results suggest that reliance on a single collection method is prone to yield only partial information for ecological assessments and emphasises the importance of employing a sampling technique that is appropriate for the study question and goals or combining more than one method. Based on these findings, we outline the scientific justifications for using each sampling method. Full article

This study presents a biomonitoring study of surface waters in the Krynka River basin, encompassing three major regional reservoirs: Khanzhenkovskoe, Olkhovskoe, and Zuyevskoe. These water bodies face significant anthropogenic pressure from mining effluents, industrial discharges, and domestic wastewater. Key pollutants identified are surfactants (SAAs), sulfates, phenols, chlorides, and manganese, with chemical oxygen demand (COD) exceeding regulatory limits. The research was conducted in September 2024. Based on the Specific Combinatorial Water Pollution Index, surface waters in the studied objects can be characterized as slightly polluted. To assess the negative impact of the identified pollutants on hydrobionts, the species composition of phytoplankton of the studied water bodies was analyzed. In the Olkhovskoe Reservoir and Olkhovaya River, cyanobacterial blooms (Oscillatoria agardhii G.) were observed, altering biodiversity in the Krynka River and Zuyevskoe Reservoir. Phytoplankton genera Synedra, Amphiprora, and Navicula—established bioindicators of aquatic ecosystem health—were dominant in Khanzhenkovskoe Reservoir, signaling nutrient enrichment and organic pollution. Changes in the species composition and structure of phytoplankton in the Krynka River, its tributaries and reservoirs, indicate a change in the level of saprobic water bodies from β to α-mesosaprobic, which indicates both the general level of surface water pollution and the accumulation of pollutants along the course of the river. The paper presents the results of fluorimetric analysis of photosynthetic activity of natural phytoplankton cells and demonstrates the possibility of using fluorescence induction curves for regular monitoring measurements. Fluorescence parameters indicate a general deterioration of photosynthetic activity of natural phytoplankton. The growth of Oscillatoria agardhii in the waters of the Olkhovskoe Reservoir and of green microalgae in the Zuevskoe Reservoir led to an increase in the fluorescence quantum yield (F_v/F_m) and the total photosynthetic activity index (PI), which makes it possible to use these parameters as indicator parameters reflecting the intensity of “blooming” of various phytoplankton species. Full article

Macroinvertebrates of the Venta River have been studied since the beginning of the 20th century. However, complex studies along the Venta River from the Latvian–Lithuanian border to its mouth into the Baltic Sea have been irregular and fragmentary. The aim of this study was to assess the ecological status of the Venta River and to analyze the abundance and fauna composition of macroinvertebrates along the entire length of the river in the territory of Latvia. This is the first study of its kind for the Venta River examining the specialization of macroinvertebrates in sediment substrates and their functional feeding groups. Within the framework of the study, the composition and functional importance of macroinvertebrates was assessed in 10 sampling sites together with the ecological quality of the river using several indices. The results show that the Venta River is dominated by benthic invertebrate collectors/gatherers, active filterers, grazers, and scrapers that have adapted to the particular type of sediments formed by silt, macrophytes, rocks, and pebbles. Different indices were calculated in order to assess the ecological quality of the Venta River. According to the saprobity index, the water quality corresponds to β-mesosaprobity, while ecological quality is mostly average; however, according to the multimetric indices, the quality of the Venta River varies from poor to high depending on the sampling station. Full article

Throughout the world, river basins are directly or indirectly affected by human activities, reducing local and global biodiversity and preventing the ecosystem from properly functioning. Our research focused on the Irpin River basin (Ukraine), whose water bodies have experienced various impacts due to human activities, including the unexpected extremes caused by military operations in the catchment area: long-term flooding, disturbance of free flow, significant water level fluctuations, etc. The study hypothesized that the primary factors determining the structural and spatial distribution of quantitative indicators of microalgae and aquatic macrophytes are the result of various hydromorphological changes, that lead to changes in the physical and chemical parameters of the aquatic environment. Very high values of chlorophyll a in the water column (59–106 µg · L⁻¹), an increase in the abundance (number of cells) and biomass of algae (due to the predominance of certain groups in the transformed sections), as well as saprobic index were recorded in the sections of the Irpin River basin that underwent significant hydromorphological changes. Our results revealed a strong correlation between phytoplanktonic (in the water column) chlorophyll a levels and water temperature (r = 0.76, p < 0.001), as well as organic phosphorus and polyphosphate concentrations (r = 0.61, p < 0.01). ANOVA and Monte Carlo permutation tests in a Canonical Correspondence Analysis (CCA) showed that the abundance of different divisions of phytoplankton and phytobenthos were significantly and similarly related to several environmental variables. We observed a positive correlation between the number of cyanobacteria and the concentration of ammonium nitrogen, nitrites, and phosphorus compounds. An increase in dissolved organic matter in the water can explain the increase in the biomass of Dinoflagellata and Euglenophyta. Species richness and the cover values of the macrophytes also clearly reflected changes in vegetation activity in sections of the Irpin River caused by hydromorphological changes. The results indicated that long-term flooding had the most negative impact on macrophyte communities. At some sites, the impact was so severe that the number of macrophyte species was very low. The total number of macrophyte species showed a significant negative correlation with total suspended solids (r = −0.51, p < 0.05) and phytoplankton chlorophyll a concentration (r = −0.73, p < 0.001). Our results provide a scientific basis for predicting changes in riverine microalgal and aquatic macrophyte communities due to extreme hydrological events. Full article

Microalgae in planktonic communities are the main producers of biomass in lake ecosystems; however, their stability is influenced by many environmental factors. This study aims to assess the ecological state of Lake Maybalyk, located in Astana (Kazakhstan), based on the study of the taxonomic diversity and structure of phytoplankton, zooplankton, and the physico-chemical properties of the water. From 2019 to 2021, samples were taken for phytoplankton analysis, hydrochemical analysis of the water, zooplankton, and saprobiological analysis of the algocenosis. The study also investigated the main morphometric parameters of the lake, as well as the composition of hydrobionts, such as zooplankton, zoobenthos, and ichthyofauna. The analysis of phytoplankton revealed the presence of 97 species and intraspecific taxa of microalgae, with 71 types of microalgal indicators indicating water saprobity. The planktonic algoflora in Lake Maybalyk is predominantly composed of diatoms (Bacillariophyta) and green algae (Chlorophyta), which play a vital role in oxygen production and the food chain within the reservoir. Based on the Pantle–Buck saprobity index (2.15–2.5), the water quality in Lake Maybalyk is classified as moderately polluted. The assessment of the water quality, considering the number and composition of indicator phytoplankton species, places Lake Maybalyk in class III (β-mesosaprobic). The hydrochemical indicators align with the hydrobiological indicators, confirming the water quality as class III. The trophic status of the reservoir, during the study period, can be described as average. The obtained data on both the hydrobiological and hydrochemical indicators correlate, suggesting satisfactory water quality and the ability of the reservoir to purify itself. This study contributes to the sustainable management of water resources, by providing essential data on the ecological state of Lake Maybalyk. The results underscore the importance of continuous biomonitoring, with microalgae as indicators of water quality, which is crucial for developing effective ecosystem conservation strategies. Full article

Benthic diatoms have been studied in different areas of the Mediterranean Sea, but no data have been available for Israeli coastal waters until the present time. In this work, the composition, ecology, and phytogeography of diatoms of the macrophytes epiphyton are presented for the first time. Altogether, 85 diatom taxa were found among the epiphyton of 25 species of green, brown, and red macroalgae from the Israeli coast between March and May of 2021. These diatoms represent three classes, 17 orders, 26 families, and 41 genera. The taxonomic composition, ecology, and phytogeography of species are discussed. The distribution of diatoms are compared to that of other macrophytes and anthropogenic loads across the shoreline. The dominant species are given. Ecological characteristics and abundance in communities of revealed species are represented and statistically analyzed. The index of saprobity S varies between 1.69–2.71. Sites that stressed aquatic communities are indicated. The influence of the anthropogenic loads on the coastal territories is defined as a major factor that stimulated diatom species richness. Sites with anthropogenic stress for aquatic communities are indicated. Based on the composition of bioindicators, it is concluded that the section of the Israeli coast studied is oligo-mesotrophic compared to the eutrophic Gulf of Tartus. Full article

It is generally accepted that mycobiota diversity in urban greenhouses is poorer than in natural ecosystems, but our knowledge on this field of research is fragmentary. Here, we present the results of a long-term study of aphyllophoroid macrofungi (Basidiomycota) forming fruitbodies on non-native sub/tropical woody and herbaceous plants in the greenhouses of Saint Petersburg, Moscow, and Ekaterinburg botanical gardens located in the hemiboreal vegetation subzone of Eastern Europe. Over 20 years of research, fruitbodies of 58 species of aphyllophoroid fungi have been identified. Fungal species that developed on the wooden structures of greenhouses and building materials made of local wood are discussed separately. The list of fungi on non-native substrates is dominated by saprobes (93.1% of total list) as well as mycorrhizal with basidiomata on plants (8.6%). Phytopathogens have the lowest number (7.0%), and ¾ of species are widespread locally. Non-native plants are dominated by native fungal species (78.9%), while the percentage of non-native species is low (21.1%). In the three surveyed cities, the area of the studied greenhouses is 2.8 ha, and not a single species of fungi has been found twice on the same substrate. Half of the identified species are characterized by a single specimen (29 species/50.9%). Hymenochaete rheicolor was discovered in Russia for the first time and its known distribution is discussed. Only six (Antrodia gossypium, Hyphodontia arguta, Lyomyces sambuci, Peniophora cinerea, Ramariopsis kunzei, and Trechispora farinacea) local species (10.5%) were collected in all the three cities. The α-diversity of mycobiota (mean number of species per site, Shannon Index, and Menhinick Index) in the Ekaterinburg’s greenhouses is 1.2–3.0 times lower compared to suburban forest parks and old-growth natural forests, while β-diversity (Whittaker Index, Jaccard Index, and Morisita–Horn Index), on the contrary, is 2.1–7.7 times higher. With the plants’ age, the probability of detecting fungi on them increases significantly. In greenhouses, phytopathogenic aphyllophoroid macrofungi are collected on woody plants only, but the probability of their development is not related to the plants’ age. Full article

We studied the species diversity and morphometric variations of rotifers from a high-altitude water body, the Llano reservoir, in central Mexico during September 2021 to August 2022. Samples were collected from four stations in the reservoir every month. During the study period we were able to identify 54 monogonont rotifer species of which Polyarthra vulgaris, Lecane closterocerca, Trichocerca porcellus, Lepadella patella and Keratella cochlearis were numerically the most abundant. Depending on the season, the total rotifer density varied from 250 to 2450 ind L⁻¹. Canonical correspondence analysis (CCA) showed that the species of Trichocerca similis, Keratella cochlearis, Mytilina ventralis and Scaridium longicaudum were directly related to temperature. Using rotifer species richness and abundance data, we derived the Shannon diversity index, saprobic index and rotifer trophic state index. Data on the geometric morphometrics showed that Keratella cochlearis was found in two of the three climatic periods of the year (dry and winter), while Lecane closterocerca and Trichocerca porcellus occurred during the three climatic seasons (dry, winter and rainy) and formed three distinct clusters in relation to body size. Full article

During our investigations of the microfungi on medicinal plants in Thailand, five isolates of Diaporthe were obtained. These isolates were identified and described using a multiproxy approach, viz. morphology, cultural characteristics, host association, the multiloci phylogeny of ITS, tef1-α, tub2, cal, and his3, and DNA comparisons. Five new species, Diaporthe afzeliae, D. bombacis, D. careyae, D. globoostiolata, and D. samaneae, are introduced as saprobes from the plant hosts, viz. Afzelia xylocarpa, Bombax ceiba, Careya sphaerica, a member of Fagaceae, and Samanea saman. Interestingly, this is the first report of Diaporthe species on these plants, except on the Fagaceae member. The morphological comparison, updated molecular phylogeny, and pairwise homoplasy index (PHI) analysis strongly support the establishment of novel species. Our phylogeny also revealed the close relationship between D. zhaoqingensis and D. chiangmaiensis; however, the evidence from the PHI test and DNA comparison indicated that they are distinct species. These findings improve the existing knowledge of taxonomy and host diversity of Diaporthe species as well as highlight the untapped potential of these medicinal plants for searching for new fungi. Full article

Afforestation of former agricultural land poses a real challenge for foresters because soil life is often severely limited by the loss of natural soil fungal diversity. In addition, former agricultural soils have low levels of fungal species typical of forest soils, which have a unique microbiome that plays a protective role (antagonists, plant growth promoters, mycorrhizal fungi, etc.). This study aimed to determine the effect of using organic material in the form of bark compost, wood waste, and sawdust to improve the soil mycobiome of soils that have been damaged by their agricultural use. This study used experimental plots established 20 years ago, and we compared the biodiversity of the treated soils with that of the control soils by analysing soil samples with powerful molecular methods. Next-generation sequencing analysis of DNA extracted from soil samples and subsequent analysis of their species composition and biodiversity showed that the mycobiome of soil fungi has been altered by the addition of various forms of organic material. The proportion of fungi belonging to the Ascomycota decreased in favour of species from the Basidiomycota and Mucoromycota. The dominant fungal groups in the soil of the control area were Sagenomella, Wilcoxina, Oidiodendron, Meliniomyces, and Penicillium. Enrichment with organic matter by adding bark compost under the roots led to an increase in Penicillium, Inocybe, and Amphinema. The application of bark compost on the surface led to an increase in the dominance of Inocybe fungi in the soil. The mycobiome of the plant to which woody debris was applied was characterised by a marked dominance of fungi of the genera Russula, Oidiodendron, and Penicillium. Similar ratios were found in the plant to which sawdust was applied, where the fungi Meliniomyces, Penicillium, Oidiodendron, and Russula dominated. A comparative analysis of fungal diversity with the Shannon diversity index showed that the most diverse fungal communities were found in the sawdust plant (6.56), while the control sample (a soil sample from an agricultural area where no organic material was applied) had an index of 5.71. After the treatments, more potential antagonists against pine pathogens and mycorrhizal fungi were found to form beneficial symbiotic relationships with them. In our opinion, the results of this study show that it is worthwhile to introduce different forms of organic matter to post-agricultural land to improve soil biodiversity and mycorrhizal associations of pine roots with fungi to ensure the sustainability of the first generation of forests created. Full article

Eutrophication is a major ecological problem and affects and endangers freshwater bodies, making assessment of the trophic status of water bodies crucial for their restoration and sustainable use. Lake Baikal is affected by a number of environmental stressors, including coastal eutrophication. Daily measurements of concentrations of nutrients, dissolved oxygen (DO), chlorophyll-a (Chl-a), weekly measurements of algae abundance and biomass in the open water season in June-December 2020, and measurements of concentrations of nutrients at 2–7-day intervals in June-October 2021 were made in the littoral of the South Baikal for the first time. It was shown that nitrate and phosphate concentrations decreased by July-August, their minimum content was maintained until September, concentrations began to increase in October and reached a maximum in December. The maximum abundance and biomass of algae and chlorophyll concentrations were only observed in early July. Storm situations increased the content of nitrogen, phosphorus and DO in water, the duration of their influence was not more than 2 days. A correlation matrix revealed significant positive correlations of NO₃⁻-DO, phosphate (SPR)-NO₃⁻, SRP-DO and biomass-Chl-a and strong negative correlations between water temperature (Tw)-DO, Tw-NO₃⁻, Tw-total nitrogen (TN) and Tw-SRP. Based on SRP and NO₃⁻ concentrations and TN:TP ratios, it was concluded that algal development was limited to nitrogen and phosphorus in summer. The trophic status of the Southern Baikal littoral zone was assessed using classifications based on TN, TP, NO₃⁻, SRP, Chl-a content and algal biomass, as well as the Carlson index (TSI) and probabilistic assessment. The results of assessments using different methods of trophic status determination showed that the Baikal littoral zone in the study area belongs to the oligotrophic type with minor elements of mesotrophy. According to the saprobity index, water purity of littoral waters varies within the oligosaprobic and β-mesosaprobic zones and corresponded to quality classes II and III (clean and moderate purity); the system demonstrates a high capacity for self-purification. Full article