Saprobic Index Research Articles

Ecological Assessment of Phytoplankton Diversity and Water Quality to Ensure the Sustainability of the Ecosystem in Lake Maybalyk, Astana, Kazakhstan

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.

Chemical composition of sediment and macrozoobenthos of small urban lakes, the Republic of Karelia, Russia

Assessing the benthic communities in water bodies under increasing anthropogenic pressure seems to be an urgent task of scientific research aimed at short-term and long-term monitoring of water bodies. This study focuses on the chemical composition of modern sediment and the current state of macrozoobenthos of small lakes in the Republic of Karelia (Kitaiskoe and Plotichie) influenced by anthropogenic factors. It was discovered that the lakes of Medvezhyegorsk have a higher concentration of heavy metals (such as lead (Pb), cadmium (Cd), molybdenum (Mo), and antimony (Sb),) compared to the Earth’s crust and natural background levels. The current study established the significant impact of industry and transportation on the movement and build up of pollutants in these lakes. The qualitative and quantitative parameters analysed for the benthic communities in the littoral and profundal zones included the species diversity, the structure of dominant species, and their percentage in the samples. According to the level of macrozoobenthos development, both reservoirs (lakes) were classified as mesotrophic, and according to the values of the chironomid index “K” as moderately polluted. The Pantle–Buck method (saprobic index) showed that the lakes can be classified as polluted (water quality class 4). Macrozoobenthos groups most tolerant to environmental conditions, for example, Chironomidae larvae, prevailed in the studied urban lakes. The economic development of the lakes leads to ecosystem transformation and long-term eutrophication over time affecting the biotic indicators of surface water quality. The results obtained can serve as a basis for complex environmental monitoring of the urbanized territories in the taiga zone.

Assessment of the ecological state of the middle Irtysh based on the development of zooplankton at the present stage

Observations in 2021–2022 showed that the zooplankton community of the Irtysh River was formed by 33 species and two forms from three systematic groups: rotifers — 19, Cladocerans were represented by 12, copepods by 2 species from the order Cyclopoida and 2 species from the orders Harpactiformes and Calaniformes. The planktofauna of the river is represented by species common to water bodies of Western Siberia. The main part of rotifers belonged to typically planktonic eurythermal species. Among the cladocerans, along with planktonic species, there were also phytophilic and benthic forms. Average zooplankton indicators for the growing season of 2021 reached 3646 specimens/m3 in numbers and 70.7 mg/m3 in biomass. In 2022, the quantitative values were slightly lower: 2237 specimens/m3 and 40.4 mg/m3. Asplanchna priodonta Gosse and Mesocyclops leuckarti Claus were dominating species in spring, Bosmina longirostris O.F. Müller in summer, Alona intermedia Sars and Ceriodaphnia affinis Lillijeborg in autumn of both years accordingly. Waters of the Irtysh River is characterized mainly by the values of indicators corresponding to the α-mesosaprobic zone. The saprobity index in spring was 1.5, in summer and autumn — 1.6, which corresponds to moderately polluted waters. In terms of a set of zooplankton indicators, the water of the Irtysh River at the present stage is somewhat different from the previous low-water period in the beginning of this century. Currently, the number of species has increased, the structure of the community has changed, in which the dominance of branchous crustaceans has been noted, the biomass has significantly increased and the saprobity index has decreased, that is, the purity of water has increased. Qualitative and quantitative indicators of zooplankton, as well as the level of saprobity, are more consistent with the period of the second half of the last century.

Benthic Diatoms on Macrophytes of the Israeli Mediterranean Coast

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.

Water Quality Of The Tirtoagung Reservoir Based On The Phytoplankton Diversity Index And The Saprobic Index In Sleman Yogyakarta

Embung Tirtoagung is an artificial aquatic ecosystem as a supplier of agricultural land during the dry season and as a fishery facility in Sleman Regency. This study aims to determine the water quality in Tirtoagung Embung based on the diversity index and saprobic index. This research is an exploratory descriptive research by way of observation. The research was conducted in February – April 2021 during the rainy season. The sampling locations were at 5 stations selected by random sampling. The results of the study showed that the water quality in Tirtoagung Embung is included in the lightly polluted category. It is known from the calculation of the diversity index that is 2,391 so that the situation is in the moderate category and the Tirtoagung reservoir is in a lightly polluted condition. Then seen from the calculation of the saprobic index, which is 0.71 - 1.00 so that the condition of the waters of the Tirtoagung reservoir is in the - mesosaprobic phase with light pollution levels and few organic and inorganic compounds. In addition, the water quality of the Tirtoagung reservoir based on physical and chemical parameters is still feasible for the survival of phytoplankton.

Phytoplankton Diversity as a Bioindicator for Water Quality of Pertamina Harbour Ampenan, Lombok

Ampenan district is an area that has a fairly high population density. There are community activities such as selling on the beach, littering, tourism activities and crossing activities at the Pertamina Harbour Ampenan which can cause a decrease in water quality. This research was conducted to determine water quality of Pertamina Harbour Ampenan based on phytoplankton community. Sea waters samplings were carried out using a 20µm plankton net. Observation and identification of phytoplankton was carried out in advances biology laboratory, FMIPA, Mataram University using a binocular microscope. Phytoplankton data were analyzed based on the abundance, diversity, dominance and saprobity index. The results of this research showed that the phytoplankton community of the Pertamina Harbour Ampenan waters consisted of 106 species from 6 classes with an abundance value of 4324,455 ind/L. Spesies diversity and dominant indexs of phytoplankton, and saprobic indexes of the Pertamina Harbour Ampenan waters were 1,767, 0,451 and 2,56 respectively. Based on the phytoplankton species diversity index, the waters of Pertamina Harbour Ampenan was categorized as moderately polluted, whereas saprobity index the waters of Pertamina Harbour was categorized as oligosaprobic.

Influence of the outflow from constructed wetlands on selected streams draining the agricultural landscape at the end of summer

We investigated the impact of the effluent from four constructed wetlands on the structure of the macroinvertebrate and macrophyte communities in the receiving watercourses including the river Pesnica and the Sejanci Stream and Pavlovci Stream in NE Slovenia. Macroinvertebrates and macrophytes were sampled on the sites upstream and downstream of the inflows. Selected environmental parameters were also analyzed on each site. Among the measured chemical and physical parameters, the concentration of NH4–N in the water was the only one that was changed significantly by the inflow from constructed wetlands (CWs). The metrics obtained on the base of the macroinvertebrate community, including the values of diversity indices, the proportion of sensitive taxa and the saprobic index, revealed no significant statistical differences between the upstream and downstream values. Inflows of effluent also have no detectable impact on macrophytes. The removal of degradable organic matter, nitrogen, phosphorus, and suspended solids from the wastewater in studied CWs was sufficient to support this situation, and this has been encouraging to construct new CWs.

Pollution status of Aneuk Laot lake Sabang based on pollution index and saprobic index

Pollution that occurs in lake waters needs special attention from various parties in the management of the lake in the future. The activities occurring around the lake result in an increased inflow of pollution into the lake. The aim of this study is to assess the pollution condition of Lake Aneuk Laot in Sabang by utilizing indicators such as the pollution index, CCME WQI (Canadian Council of Ministers of the Environment Water Quality Index), and saprobic index. The investigation took place in both September 2019 and June 2021, employing the stratified random sampling method with four designated observation stations for the sampling process. Parameter measurements analyzed in the pollution index include temperature, depth, current, TDS, TSS, BOD, COD, DO, phosphate, nitrate, ammonia, sulfide, iron, lead, oil and fat, detergent, pH, e-coliform, and parameters used in the saprobic index include phytoplankton data. Based on the analysis of the Pollution Index and CCME WQI it is determined that the pollution status of Lake Aneuk Laot is heavily polluted for Class I, moderately polluted for Classes 1 and 2, and falls under the good category for Class 4. The saprobic index results show the beta-mesosaprobic category with a result of 2.3 (moderately loaded).

Characteristics of phytoplankton functioning in urban water reservoires (based on the example of Basivkut Reservoir, Ukraine)

The study states fundamental patterns of development for species and taxonomic composition, structure and seasonal population dynamics, biomass and informational diversity of phytoplankton in Basivkut Reservoir. During the research (June–October, 2022) it has been identified 121 algae species represented with 125 intraspecific taxa that belong to 84 genera, 43 families, 29 orders, 12 classes and 8 divisions. Floristic aspect of plankton algae is presented with Chlorophyta (40.1% of the total species number), Bacillariophyta (26.4%), Euglenozoa (13.2%) and Cyanobacteria (12.4%). The population of phytoplankton in Basivkut water storage was ranging from 4654 thous. cells/dm3 to 14212 thous. cells/dm3 (August), and the population of biomass was changing from 0.8732 mg/dm3 (July) to 9.4828 mg/dm3 (October). Shannon index has changed within 0.62–5.07 bit/mg according to biomass, 2.13–4.50 bit/sp. according to the population. The average values of the saprobic index have ranged from 1.74 to 2.14 that correspond to the third class of water quality (poorly polluted). The author highlights the increasing of Cyanobacteria development whose population and biomass reached 86.1% and 33.2% that caused intensive algal blooms in all summer months and is the impact of algal groups on the anthropogenic factors effect and climate changes. Aphanizomenon flos-aquae (10.5–32.2% and 10.6–12.4%) and Cuspidothrix issatschenkoi (11.6–31.2% and 10.2–14.5%) have dominated according to their population and biomass. Bacillariophyta impacted on population (39.5–74.0%) and biomass (88.7–98.4%) in autumn. Small cell type Stephanodiscus hantzschii has been characterized with significant population (16.9–65.4%) and biomass (51.1–92.9%) that focuses on increasing degree of trophic level in the Basivkut water storage.

Phytoplankton communities of reservoirs of the forest-steppe zone under conditions of technogenic load

On the example of the rivers Oskolets and Chufichka, flowing into the river Oskol, the phytoplankton of small rivers of the forest-steppe zone of the Belgorod region, which are of technogenic origin, is considered. The taxonomic and ecological composition of communities of microalgae and cyanobacteria was studied in order to determine the ecological and biological state of surface waters of the Starooskol-Gubkinsky mining region of the Kursk magnetic anomaly. Everywhere in the waters of the watercourses under consideration, cyanobacteria species characteristic of polluted habitats, as well as species recognized as producers of cyanotoxins, are observed. Among them are Ostillatoria granulata Gardner, Ostillatoria guttalata van Goor and Ostillatoria putrida Ag., Ostillatoria splendida Grev. The quality class of the studied waters is defined as the III-rd «Satisfactory purity», and in some cases - as the II-nd, that is, the waters are «Clean». It has been established that the processes of water self-purification proceed intensively. However, the quality of waters determined by the Pantle-Bukk saprobity index in the modification of V. Sladechek within the limits of III and
 II classes does not indicate their ecological well-being, since a number of species of cyanobacteria and diatoms show teratological changes, which are expressed in somewhat “blurred” outlines. their appearance. In addition, an abundance of mineral particles associated with the reduction activity of nitrogen bacteria is observed almost everywhere in the waters.

PHYTOPLANKTON IN THE LAKES OF THE REPUBLIC OF BASHKORTOSTAN

The phytoplankton in a number of lakes in the Bashkir Trans-Urals (Atavdy, Sultankul (2017), Bursunsy, Kuldybay (2019), Bolshiye Uchaly, Uzunkul (2021)) and Bashkir Pre-Urals (Bolshoy Tolpak, 2022)) was studied. As a result of the study, the taxonomic structure, quantitative characteristics, dominant species, distribution features of main algal groups were reveald, and their ecological and geographical characteristics werre identified. 257 species and intraspecific taxa of algae from 9 divisions were registered in the algal flora. Green algae (33%), cyanoprokaryotes and diatoms (21% each of total species number) show the highest species diversity in the lakes. The algal flora is specific for each lake and has low degree of floristic similarity (0.13–0.57 according to Sørensen coefficients). In the ecological and geographical terms, the algal floras of lake plankton is represented by typical planktonic species, widespread in waterbodies of the globe, indifferent to water salinity, living only in fresh waterbodies and preferring neutral waters. Quantitative indicators of phytoplankton varied in a wide range of values: number of cells from 4.4 to 344 mln cells/L, biomass from 0.23 to 22.97 mg/L. Dominant species in terms of abundance are represented predominantly by cyanoprokaryotes (Snowella lacustris, Aphanocapsa delicatissima, A. incerta, Aphanizomenon flos-aquae, Gloeotrichia echinulata, Merismopedia tenuissima, Pseudanabaena galeata, Planktolyngbya limnetica, Woronichinia compacta, Anathece clathrata, Rhabdoderma lineare), in terms of biomass by green (Oocystis lacustris, O. borgei, O. marssonii, Scenedesmus apiculatus), dinophyte (Peridinium cinctum, Gymnodinium sp., Ceratium furcoides), desmidium algae (Staurodesmus cuspidatus, Cosmarium contractum, C. cucumis) and cyanoprokaryotes (Pseudanabaena galeata, Aphanizomenon flos-aquae, Gloeotrichia echinulata). According to the value of the saprobity index (Pantle – Bucc by number 1.57–2.80), the lake waters correspond to β- and α-mesosaprobic types of waterbodies with III and IV water quality classes (moderately polluted or dirty water).

The Resistance of Waters to Trophy Increases as a Result of Processes in Their Ecotone Areas (according to Phytoplankton Indicators)

According to the saprobity index, estimated by the phytoplankton biomass, the degree of organic pollution of ecotone areas (the mouth of the Il’d River and the littoral of the Volga reach of the Rybinsk reservoir) was determined. The saprobity index in protected shallow waters was 1.83 in 2009 and 2.07 in 2010; in the pelagial – 2.14 and 2.13 in 2009 and 2010 respectively. In the “river-reservoir” system, the lowest average values of the saprobity index were noted in the mouth area of the Il’d River: in 2009 – 1.94, in 2010 – 1.87, in 2011 – 1.88. In the river and the reservoir, its values were higher: 2.05 and 2.07 in 2009, 1.96 and 2.08 in 2010, and 1.97 and 1.99 in 2011 respectively. The decrease in saprobity in shallow waters and at the mouth of the river, compared to the bordering water, indicates a higher intensity of self-purification processes, which can ensure the sustainability of the ecosystem of the reservoir as a whole. Abnormal weather phenomena, in particular, high summer water temperatures, can lead to destabilization of the features of ecotone algocenoses, as a result, to a violation of the process of self-purification of the reservoir.

Reynolds phytoplankton functional classification approach helps evaluate the historical ecological status of the large European Southern Bug River (Ukraine)

AbstractThe phytoplankton functional group (FG) classification system sensu Reynolds enables evaluating the ecological status of rivers using the Q(r) compositional index. Here, we apply the Q(r) index to analyze the ecological conditions of the Southern Bug River, at the entire river length, in the early 20th century, testing it first on historic river phytoplankton data. Moreover, we combined the FG approach with the saprobic index and taxonomic richness to assess the ecological status of the river more reliably. The Bray–Curtis Similarity index highlighted the spatial clustering of river sites that corresponded well to the bioregions of the Eastern Lowlands and the Pontian Province. The Q(r) index revealed a higher variation in ecological status among sites than the saprobic index. Therefore, we argue that the FG approach provides a sensitive ecological status indication approach for river phytoplankton, including historical human impacts. The method may improve understanding of reference conditions and assessing the ecological status of Ukrainian rivers, as requested by the European Water Framework Directive.

ASSESSMENT OF WATER QUALITY OF URBANIZED TERRITORIES ACCORDING TO THE STRUCTURE OF HYDROBIONT GROUPS

The paper proves the possibility of conducting water quality assessment using such an indicator as the species assemblage of Unionidae habitats for the purpose of conducting local bioindication. According to the species assemblage of Unionidae habitats, it was established that of the five analyzed sites of material collection of the main stream of the Teteriv River, in one case the water quality can be assessed as "Dirty", which corresponds to the IV water quality class, and in three cases as "Contaminated", which corresponds to the III class, and in another one - as "Good" - II class of quality. The rivers Guiva (Ivankiv), Kroshenka and Putyatinka within Zhytomyr belong to the IV class of water quality. Five more points are assigned to the II quality class (Guyva River in the area of Pryazhevo and Zarichany villages; Kam'yanka River (Zhytomyr); Kodenka River (Vertokiyivka village) and Hnylop'yat River (Berdychiv).More detailed information about the ecological state of aquatic ecosystems is provided by the use of algal communities of plankton as biological descriptors, but this approach is time-consuming. In general, the bioindication of water quality in the rivers of the Teteriv basin according to phytoplankton showed the predominance of indicators of saprobity, which correspond to the III class of water quality ("Contaminated"). Class II ("Good") indicators make up a significant share. A moderate level of organic water pollution is indicated by the predominance of eurysaprobes in the rivers. In terms of phytoplankton biomass, the Teteriv and Kroshenka rivers belong to the III class of water quality, other watercourses belong to the II class. According to the saprobity index, the water quality of the Teteriv, Putyatinka, and Kroshenka rivers is rated as satisfactory, and that of other watercourses as good. According to primary production and the ratio of production and destruction processes, watercourses were ranked into three groups - those belonging to II, III and IV water quality classes. The average values of the integral index ∑А/∑R for all watercourses, except for the Putyatinka River, are higher than 1. This indicates a positive balance of organic matter, characteristic of aquatic ecosystems with a high intensity of photosynthesis. The predominance of the heterotrophic phase in Putyatynka is most likely a response of the watercourse ecosystem to anthropogenic pressure.A comprehensive assessment of the water quality of watercourses in urbanized areas using as biological descriptors the ecological state of hydroecosystems of algae, plankton and mollusk settlements is the foundation for further ecological monitoring of waters, forecasting changes in the autotrophic and heterotrophic links of aquatic ecosystems under the influence of environmental factors.

CLADOCERA COMMUNITIES OF LAKE ARCTO-PIMBERTO (NENETS AUTONOMOUS DISTRICT) IN THE MIDDLE AND LATE HOLOCENE<a href="#FN1"><sup>1</sup></a>

The analysis of the subfossil Cladocera community in the bottom sediments from Lake Arcto-Pimberto located in the Pechora River delta (Nenets Autonomous District) was carried out. A 95-cm-long continuous core of bottom sediments was collected in the deepest part of the lake and covers approximately 6400 years of sediment accumulation during Middle and Late Holocene. 17 cladoceran taxa were identified in the studied core. Species with Holarctic and Palearctic distributions prevailed in the lake. Most of the identified subfossil remains belong to pelagic species living in the open part of the lake. Found fragments of chitinized remains of Rhynchotalona falcata and Alonopsis elongata indicate the presence of sandy soils in the water body. The samples were dominated by Bosmina (Eubosmina) longispina and Chydorus cf. sphaericus, which are evenly distributed along the continuous sediment core. We have studied the history of the development and evolution of the lake based on changing of the taxonomic composition of microcrustaceans in the bottom sediment core. The structure of the subfossil Cladocera community stayed relatively constant. The ratio of pelagic and littoral-phytophilic taxa changed slightly. Depending on the changes in the species composition of the cladoceran assemblage, the sediment core was divided into 4 ecological zones. In the early history of sedimentation in the lake, there is a small peak in the abundance of crustaceans, followed by decrease and further gradual increase towards the upper horizons of the column. Between from 5700 cal. years BP to 2100 cal. years BP there is an increase in abundance of pelagic organisms, with a decrease in abundance of littoral taxa. This marks the presence of a well-developed pelagic part of the reservoir at that time. In the upper zones, we observe the taxonomic diversity of littoral organisms and an increase in abundance of their remains. The Shannon-Weaver species diversity Index showed a simple organization of the community of subfossil Cladocera. The Pantle and Buck saprobity Index characterized the lake as oligosaprobic, this status is maintained throughout its evolution of the lake.

Identification of River Water Pollution Based on Saprobic Index of Macrozoobenthos in Anggokoine River, Oheo Sub-District North Konawe District

Study of identification of water pollution based on Macrozoobenthos Saprobic index identify was carried out. The aims of the research are to identify types of macrozoobenthos existing on the Anggokoine River and to identify river water pollution condition based on macrozoobenthos saprobic index at the Anggokoine River. The method used in the research is the direct observation method, collection of primary and secondary data. Analysis of Macrozoobenthos Saprobic Index used the Ravera (1979) Index and also water pollution index for the physicochemical characteristic of river water. The result at the research reveals that the Anggokoine river was categorized as mildly polluted based on physicochemical condition. It was found that 14 kinds of benthos which consist of six families with Bivalvia, Pelecypods and Gastropoda classes. Based on Macrozoobenthos Saprobic Index at Station I and II, it was analyzed that the Saprobic Index value is 2.6 and 2.6 namely categorized as α-Mesosaprobic and it is indicated that the Anggokoine river is heavily polluted. Station III it was analyzed that the Saprobic Index value is 2.3 namely categorized as β-Mesosaprobic and it is indicated that Anggokoine river is have polluted.

The Ecosystem of Lake Tolpanjärvi, Western Karelia, Preserved in Natural State

The results of the study of Lake Tolpanjärvi’s ecosystem are reported. Its hydrological and geochemical indices, as well as the current condition of biotic communities (zooplankton, benthos and fish population), were studied and analyzed. Analysis of the chemical composition of water indicates the low organic matter content (total phosphorus 0.007 mg/l, nitrogen 0.26 mg/l) of the lake. The Tolpanjärvi is an oligotrophic lake, as indicated by the abundance of zooplankton (with a biomass of less than 1 g/m3) and zoobenthos (biomass 0.44 g/m2). The lake is of an oligosaprobic class (2nd quality class, clean natural water), as evidenced by its saprobity index estimated using Pantle–Bukk’s method. The quantitative indices of zoobenthos varied from 120 individuals/m2 and 0.08 g/m2 in the profundal zone to 1200 inds./м2 and 0.86 g/m2 in the quiet littoral zone. The lake is more similar in the chironomid index (К – 2.00) to clean natural water. It is inhabited by 8 fish species of 5 families. The fish population is dominated by the whitefish Coregonus lavaretus, the perch Perca fluviatilis and the roach Rutilus rutilus. Two ecological forms of whitefish, differing in both the number of gill rakers (sparsely-rakered 18–24 and medium-rakered 28–36) and biological indices (linear-weight growth рост, maturation, fertility and feeding), occur in the lake. Stable highly diverse ecosystems were shown to form the basis for the preservation of the gene pool and for assessment of the current condition of water bodies heavily affected by human activities.

Seasonal Diversity and Morphometric Variations of Rotifers in Relation to Selected Environmental Variables from a Tropical High-Altitude Lake in Mexico

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.

Diatoms. A viable tool for quantifying surface water pollution

The current work focused on the water quality of the Bega and Timis rivers measured by two methods. One of them is the method by which the water was analyzed from a physical-chemical point of view, and the other aimed at quantifying the degree of water pollution by biological methods. In this sense, diatoms were used. In the study, samples of water and diatoms were taken using specific techniques from the Bega and Timis rivers, starting from near the area of their formation until near the border with Serbia. Four sampling points were chosen on the Timis River plus one sampling point on the Surgani River, which is a tributary of the Timis, and six sampling points on the Bega River. The points were chosen specifically, being located downstream of the major sources of pollution. In order to locate the points, information was collected from the studies carried out as part of an extensive monitoring that spanned several years. The abundance and diversity of diatom species were used to calculate the Biological Diatom Index (BDI) and the Saprobity Index (SI). These two indices provide valuable information about organic or heavy metal pollution of water bodies.

STUDY OF THE DIVERSITY OF THE ALGOFLORA OF THE IRTYSH RIVER AND ISOLATION OF NEW STRAINS OF PHOTOTROPHIC MICROORGANISMS

The article presents the results of studies of the diversity of the composition of the algoflora of the Irtysh River in the Pavlodar region.85 species of microalgae were detected in water samples from different points of the Irtysh River.According to the frequency of occurrence, the main part of it is made up of green and blue-green algae.Analysis of individual species of saprobic microalgae revealed the presence of 16 species of indicator microalgae of the Irtysh River.The saprobity index for bioindication analysis is 1.8 (β-mesosaprobic). According to the results of work on the extraction of pure cultures from samples taken from the Irtysh River, 5 algologically and bacteriologically pure cultures of microalgae were obtained: Oscillatoria tenuis A-1, Phormidium autumnale D-2, Anabaena Variabilis A - 2, Synechococcus elongatus D-6, Nostoc calcicola YAD-3 were isolated.