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Global climate change might result in permafrost thaw and the formation of thermokarst landscapes that release long-term carbon stocks as greenhouse into the atmosphere, thereby initiating a positive climate feedback. These processes are mediated by biological activity, including by microbes, vascular plants and animals, whereas the role of invertebrates in thermokarst ecosystems remains poorly understood. We investigated the diversity and assemblage structures of zooplankton (mainly Copepoda, Cladocera), microbenthos (testate amoebae) and meio- (Copepoda and Cladocera) and macrozoobenthos (mollusks, crustaceans, insects and annelids) from a range of water bodies representing different stages of thermokarst lake formation in the southern part of the Lena River Delta (Central Siberia). Altogether, 206 species of testate amoeba, mollusk, crustacean, insect and annelid taxa were identified. A total of 60 species of macrozoobenthos (mainly insects) and 62 species of testate amoebae were detected in the water bodies of the Lena River Delta for the first time. The species richness of zooplankton and meio- and macrozoobenthos was greater in the large thermokarst lakes than in the polygonal ponds due to the freezing of the latter in the winter. In contrast, the species richness of protists was higher in the polygonal ponds, which was related to the habitat preferences of testate amoebae. Fish grazing strongly affected the macrobenthos assemblages but not the smaller-sized organisms. Water acidity and temperature were the main environmental drivers of the assemblage structure of testate amoeba and microcrustacean. The species structure of the macroinvertebrate assemblages was significantly explained by water acidity, permafrost depth and size of the water area. It means that small size organisms with their short generation times are sensitive to more dynamic factors such as temperature and may serve as indicators of ecosystem changes due to global climate warming. In contrast, large size organisms are affected by driven factors that appear during thermokarst lakes formation and permafrost degradation.

Purpose. Investigate ecological conditions and determine fish productivity of ponds when growing young-of-the-year carp using a suspension of chlorella. Methodology. During the study, we used methods generally accepted in hydrochemistry, hydrobiology and fish farming. Findings. The article presents the results of the study on the use of chlorella suspension in the cultivation of carp. It was found that the use of chlorella suspension created favorable hydrochemical conditions resulting in intensive development of zooplankton, which had a positive effect on the growth of young-of-the-year carp and fish productivity of the pond. The development of the natural food supply was sufficient to meet the nutritional needs of juvenile carp. The average seasonal biomass of zooplankton in the experimental pond was 28.68 g/m3 that was 1.5 times higher than in the control. The share of cladocerans in the total biomass of zooplankton in the experimental pond was 76.6%, versus 36.8% in the control. The average biomass of zoobenthos for the growing season in the experimental was 1.3 times higher than in the control, and was formed by chironomid larvae, which are valuable in the food chain. Originality. The study investigated ecological conditions and fish productivity of growing ponds under conditions of the application of cattle manure and suspension of chlorella when growing carp in monoculture. Practical value. It was found that the use of chlorella suspension promotes the intensification of the development of zooplankton organisms in ponds. The obtained data can be used to develop practical recommendations for optimizing the conditions for growing carp seeds and increasing the biological productivity of ponds. Key words: nursery ponds, natural food supply, phytoplankton, zooplankton, zoobenthos, young-of-the-year carp, chlorella suspension, fish productivity.

Taxonomic composition and distribution of species of zoobenthos of the Kagul Lake have been studied. 36 species were found out. 28 species are met in coastal shallow waters, 20 species are beyond its bounds. The number of larvae of Chironomus, Olygochaeta, Polychaeta,Amphipoda,Gastropoda and Bivalviais most frequently come across., Приведены результаты изучения таксономического состава зообентоса озера Кагул, распределения видов по акватории озера на прибрежном мелководье и за его пределами летом 2004 - 2005 гг., З’ясовано таксономічний склад та розподіл видів озера Кагул. Всього знайдено 36 видів. На прибережному мілководді зустрічається 26 видів, за його межами — 20. Найбільша частота стрівальності властива личинкам хірономід, олігохет, поліхет, амфіпод, черевоногих і двостулкових молюсків.

The quantitative characteristic of the lake Kagul zoobenthos is investigated. Decrease in the number and biomass is observed from the upper to the lower reaches off the lake. The number of zoobentos attain 2000ex/m2 and more, biomass — 42,2 g/m2. the greatest contribution in to the number have oligohet and larvae insects, in biomass — molluscum. Olygocheta and larvae of insects make the highest value in benthos number, and mollusks in biomass., Изучена количественная характеристика зообентоса озера Кагул. Значения численности и биомассы уменьшаются от верховья к низовью озера. Численность зообентоса достигает 2000 экз/м2 и более, биомасса — 42,2 г/м2. Наибольший вклад в численность бентоса вносят олигохеты и личинки насекомых, в биомассу — моллюски., З’ясована кількісна характеристика зообентосу озера Кагул. Значення чисельності і біомаси зменшуються від верхів’я до низов’я озера. Чисельність зообентосу досягає 2000 екз./м2 та більше, біомаса — до 42,2 г/м2. Найбільший вклад у чисельність бентосу вносять олігохети та личинки комах, в біомасу — молюски.

The benthic macroinvertebrate community is composed of some organisms that are more sensitive and others more resistant to environmental changes. In this sense, they are used as a bioindicator. The present work aimed to verify the local species diversity (alpha diversity) of the macroinvertebrate community in two stretches of the Lower Rio Grande Basin with distinct substrate composition. The study was carried out at two sites on the Rio Grande. At point 1, sediment samples were collected over a period of twelve months, where the diversity index of the parameters richness (S), abundance, dominance, Shannon-Wiener diversity (H'), Simpson diversity (D') and equitability (J) were calculated and through the non-parametric Kruskal-Wallis analysis were compared between all the months of the year, as well as the rainy and dry seasons. At point 2, artificial objects were calculated and diversity indices were calculated, also including the rainy and estimation seasons. In point 1 there was no significant difference between the rainy and dry seasons, but there were differences in abundance and evenness between all months sampled. In point 2 it was evident that the diversity index values were higher during the dry season. In summary, it was inferred that the benthic communities may be under the reflex of environmental homogenization resulting from anthropic activities. Therefore, these diversity indices can be an adequate tool to understand the environment, and thus promote more assertive mitigation decisions in favor of the conservation of species. La comunidad de macroinvertebrados bentónicos está compuesta por unos organismos más sensibles y otros más resistentes a los cambios ambientales. En este sentido, se utilizan como bioindicador. El presente trabajo tuvo como objetivo verificar la diversidad de especies locales (diversidad alfa) de la comunidad de macroinvertebrados en dos tramos de la cuenca del Baixo Rio Grande con diferente composición de sustrato. El estudio se llevó a cabo en dos puntos de la cuenca del Baixo Rio Grande. En el punto 1 se colectaron muestras de sedimentos lo largo de doce meses, donde el índice de diversidad de los parámetros riqueza (S), abundancia, dominancia, diversidad de Shannon-Wiener (H'), diversidad de Simpson (D') y equitatividad (J) y mediante a comparacion análisis no paramétricos de Kruskal-Wallis entre todos los meses del año y también las estaciones lluviosa y seca. En el punto 2 se calcularon los objetos artificiales y se calcularon los índices de diversidad, incluyendo además las épocas de lluvia y de estimación. En el punto 1 no hubo diferencia significativa entre las estaciones lluviosa y seca, pero sí entre abundancia y uniformidad entre todos los meses muestreados. En el punto 2 se evidenció que los valores de los índices de didersidad fueron mayores en los meses secos. En resumen, se infirió que las comunidades bentónicas pueden estar bajo el reflejo de la homogeneización ambiental producto de las actividades antrópicas. Por tanto, estos índices de diversidad pueden ser una herramienta adecuada para entender el medio ambiente, y así promover decisiones mitigadoras a favor de la conservación de las especies más asertivas. A comunidade de macroinvertebrados bentônicos é composta por alguns organismos mais sensíveis e outros mais resistentes as mudanças ambientais. Nesse sentido, são utilizados como bioindicador. O presente trabalho teve como objetivo verificar a diversidade de espécies local (diversidade alfa) da comunidade de macroinvertebrados em dois trechos da Bacia do Baixo Rio Grande com composição de substrato distintos. O estudo ocorreu em dois pontos da Bacia do Baixo Rio Grande. No ponto 1 foram coletadas amostras de sedimentos ao longo de doze meses, onde foram calculados o índice de diversidade dos parâmetros riqueza (S), abundância, dominância, diversidade de Shannon-Wiener (H'), diversidade de Simpson (D') e equitabilidade (J) e por meio da análise não paramétrica Kruskal-Wallis foram comparados entre todos os meses do ano e também estação chuvosa e de estiagem. No ponto 2 foram coletados substratos artificiais e foram calculados os índices de diversidade, compreendendo também as estações chuvosas e de estiagem. No ponto 1 não houve diferença significa entre as estações chuvosas e de estiagem, mas apresentou diferenças entre a abundância e equitabilidade entre todos os meses amostrados. No ponto 2 foi evidenciado que o valores dos índices de diversidades se apresentaram maiores nos meses de estiagem. Em síntese, foi inferido que as comunidades bentônicas podem estar sob o reflexo da homogeneização ambiental resultantes das atividades antrópicas. Portanto, esses índices de diversidades podem ser uma ferramenta adequada para compreender o ambiente, e assim fomentar decisões mitigadoras em prol da conservação das espécies mais assertivas

The species composition of one of the main zoobenthos groups in Vaya Lake - Chironomidae (Diptera) in the period 2003 - 2007 was studied. A total of 27 taxa were identified, of which 18 species from 11 genera were identified and 9 taxa at the level of sp. The results showed a change in the species composition of chironomids compared to the period 1953 - 1957 (Zashev and Angelov, 1959) when the only systematic studies of the lake so far were performed.

The article is devoted to the study of seasonal dynamics and quantity of the zoobenthos distribution in the north-west part of the South Caspian Sea. During the research covering the period from 2009 until 2010, 59 macrobenthos organisms belonging to the ten systemic groups were identified. Maximum quantity of species was identified in spring and summer (31 - 59 species), while minimum in autumn (24 - 42 species). Maximum development of organisms was identified in summer (146.27 g m-2), while minimum in autumn (77.12 g m-2). The key role in the benthos biomass formation belonged to shellfish, comprising 67.7 to 69.1% of total benthos biomass

Gut microbiota is closely related to the health of the host and its adaptation to environmental changes. Sinopotamon planum is a species of freshwater crab that lives in the water for three seasons and plays a key role in freshwater ecosystems as a benthic macroinvertebrate, an important indicator of aquatic ecological health. In this study, we sequenced 60 gut microbial samples of S. planum and nine microbial samples from the surrounding water in spring, summer, and autumn based on the 16S rRNA gene. The results showed that gut microbiota had the highest alpha diversity in summer, which may be related to increased adaptability in summer. Firmicutes, Proteobacteria, and Bacteroidota were the most dominant phyla of gut microbiota across three seasons, with Candidatus Hepatoplasma and Candidatus Bacilloplasma being the main genera. These main phyla and genera may be key to maintaining a stable function of the intestinal environment. Firmicutes was the phylum with the highest relative abundance, which is probably related to the carnivorous behaviour of S. planum. The abundant C. Hepatoplasma may be related to the starvation of S. planum in the wild. In both gut and water microbiota, beta diversity analyses showed significant differences across seasons. Comparative analysis of gut microbes and surrounding water microbes showed significant differences in microbial diversity and composition between gut and surrounding water. In conclusion, the structure of the gut microbial community of S. planum differed significantly between the studied seasons, but the water microbial community around S. planum was less variable and significantly different from the gut microbes. The seasonal differences in gut microbes are more likely the result of self-internal adaptation to changes in water temperature and food resources between seasons.

Urban aquatic ecosystems are important sources of fresh water for multiple uses, but often receive a point or diffuse anthropic contamination. Benthic and zooplankton invertebrates are sensitive to water quality, being good indicators of ecosystem health. In this study, the composition and structure of benthic and zooplankton communities and environmental variables were analyzed seasonally in six urban wetlands of Santa Fe City (Argentina). We present the effect of water quality on both communities as bioindicators of ecological conditions, using different community attributes, functional feeding groups, and biotic indices. For the benthic community, the Macroinvertebrate Index for Pampean Rivers (IMRP) and the Benthic Community Index (BCI) were selected. For the zooplankton community, abundance of rotifers/abundance of total zooplankters, microcrustaceans/total zooplankters, cladocerans/total zooplankters, and macrozooplankton/microzooplankton ratios were applied. A functional feeding groups (FFGs) classification, adapted from the literature, is proposed for zooplankters. The urban wetlands showed a gradient from the most to the least disturbed sites. Some benthic and zooplankton species were identified as excellent bioindicators of pollution, and the FFGs and biotic indices revealed the ecological condition of each urban wetland. The present study contributes to the enhancement of management practices in urban landscapes aiming to maintain ecosystem services in sustainable cities.

Purpose. To investigate the peculiarities of the formation of hydrochemical, hydrobiological regimes and to determine the fish productivity of nursery ponds under a complex exposure to their ecosystem. Methodology. The work was conducted according to generally accepted hydrochemical, hydrobiological and aquaculture methods. Findings. The article presents the results of the study on the productivity of nursery ponds when using a complex of intensification measures (fertilization with traditional fertilizers, application of chlorella paste, polyculture, and fish feeding). It was found that the main hydrochemical parameters during the rearing of cyprinid fingerlings were within the standard normal values ​​and were favorable for the development of prey organisms and the cultivation of fish seeds. Positive trends were obtained after the use of chlorella paste when growing juveniles of cyprinids in polyculture with different ratios of common carp and Chinese carps. The use of the chlorella paste in combination with other intensification measures in the experimental ponds created favorable conditions for the development of natural food supplies, growth and survival of cyprinid fingerlings. At the same time, the total fish productivity in the experimental ponds was 22.0-28.0% higher, and the feed costs were 1.1-1.3 times lower than in the control ponds. Originality. The peculiarities of the formation of hydrochemical and hydrobiological regimes have been investigated and the fish productivity of nursery ponds has been determined using cattle humus and chlorella pasta when growing young-of-the-year carp in polyculture with silver and bighead carp hybrids. Practical value. The obtained data can be used for developing practical recommendations regarding the optimization of the conditions for growing cyprinid seeds in polyculture using the chlorella pasta, increasing the efficiency of managing the state of aquatic ecosystems and their biological productivity.

The data on the taxonomic composition and quantitative characteristics of planktonic and benthic communities of the Lower Don in the area of construction of the Bagaevsky hydroelectric complex have been presented. In June - July 2018, a comprehensive hydrobiological survey was carried out to assess the taxonomic composition and quantitative characteristics of phytoplankton, zooplankton and zoobenthos. Hydrobiological samples were taken at 21 stations using standard techniques. The phytoplankton communities contained 110 taxa, zooplankton - 58, zoobenthos - 78. The spatial distribution of quantitative indicators of plankton and benthos in the investigated area has been presented. Phytoplankton abundance varied from 2,006.0 to 6,128.0 million cells/m, biomass - from 1.00 to 7.37 g/m, the average polygon indicators were 3,636.6 ± 223.5 million cells/m and 4.28 ± 0.39 g/m respectively. In terms of the number of registered taxa and quantitative indicators, two groups of phytoplankton dominated - cyanobacteria and green algae. The abundance of zooplankton ranged from 2,580 to 238,622 ind./m, biomass ranged from 36.4 to 476.0 mg/m, the average abundance was 74,690 ± 15,017 ind./m and 172.7 ± 24.8 mg/m respectively. Rotifers and cladocerans were the leaders in the number of species. Meroplankton was dominant in numbers (mainly due to mollusk larvae), and copepods were the dominant group in biomass. The number of bottom invertebrates varied from 20 to 17,867 ind./m, biomass from 0.02 to 2,114.0 g/m, the average zoobenthos abundance was 3,462 ± 898 ind./m, biomass 133.9 ± 102.0 g/m respectively. The maximum number of taxa was recorded among crustaceans and chironomid larvae. The basis of abundance was formed by oligochaetes and insect larvae, mainly chironomids, mollusks dominated by biomass. The resulting materials can be used as background materials in assessing the impact of construction on the hydrobiological communities of the Lower Don.

Purpose. The work is aimed at estimating the organic carbon abundance in the bottom sediments of the littoral zone in connection with the state of macrozoobenthos in the Sevastopol region coastal waters with different levels of the anthropogenic pressure (by the example of the Laspi Bay). Methods and Results. The samples were taken in the dynamically active coastal-shelf zone (up to the depths ~ 20 m) of the Laspi Bay in September, 2017. Two samples were taken during the 103rd cruise of R/V "Professor Vodyanitsky" (September, 2018). The geochemical composition of bottom sediments was investigated. The bottom sediments of natural humidity were analyzed in accordance with the requirements of the regulatory documents. In the sediments containing the aleurite fraction in the central part of the Laspi Bay (station 4), the organic carbon content (Сorg) increased its natural course up to 0.46 %, but did not exceed its maximum values characteristic of the similar lithological sediments in the shallow-water part of the Crimea Southern Coast (1.14 %). In the deep part of the bay occupied with the aleurite-pelitic silt, the Сorg content exceeded 2 %. Absence of the Сorg accumulation within the depths under study is conditioned primarily by the grain-size composition of the bottom sediments, the hydrodynamic factor and the morphometric features of this coastal site. Presence of a small portion of the aleurite-pelitic fraction in the bottom sediments also does not promote the organic carbon accumulation. Thus, spatial distribution of the carbon organic and inorganic forms is conditioned by the features of the matters’ lateral migration, which, in its turn, is governed by dependence of the bottom sediments’ chemical and dispersion structure upon the environmental morphodynamic conditions. Conclusions. The littoral sediments were found to be characterized by a low organic content (Сorg = 0.16 %) not exceeding the geochemical background values of the surface bottom sediments in the Black Sea shelf zones. At present, the organic matter accumulation is determined by the features of the environmental morphodynamic conditions (transition of fine particles to the deep zones) and by the dispersed composition of the bottom sediments.

The goal of this investigation was to assess the role of a number of environmental variables on the traits of a peracarid population inhabiting turfs of Ellisolandia elongata in a Mediterranean disturbed location. Samples were collected from a vertical and a horizontal surface to assess the role of orientation, and several structural traits of the turf (number of fronds, their height and width, available phytal area for colonization, and dry weight) were measured. The samples were characterized by their species composition, relative abundance of constant species, total abundance of individuals, and α-diversity (species richness, Shannon index and Pielou’s evenness). Generalized linear models were used to relate environmental variables with ecological descriptors, whereas a cluster plot and a principal correspondence analysis, both based on the Bray-Curtis coefficient, were conducted to detect the presence of distinct assemblages. Results showed orientation to be a key factor governing the assemblages, since samples from vertical and horizontal surfaces formed definite groups based on Bray-Curtis similarities. Moreover, GLMs pointed out that orientation influenced relative abundance of the majority of constant species, as well as species richness and Shannon index. Phytal height had a positive effect on the relative abundances of Hexapleomera bultidactyla, Coxischyrocerus inexpectatus and Hyale stebbingi, and a negative one on Shannon index and evenness, whereas available phytal area influenced positively evenness and negatively the relative abundance of Elasmopus pocillimanus. Thus, it can be inferred that although species composition depended on surface orientation, the spatial structure of the turf was the main driver for assemblage complexity, Partial fnancial support was received from the Spanish Ministry of Science and Innovation [Research Project “Polychaeta VI: Palpata-Canalipalpata I (CGL2014-53332-C5-3-P)”]

Лаишевский район Республики Татарстан, примыкающий к г. Казани, в настоящее время активно застраивается. Последствиями антропогенного воздействия являются сокращение площади водосборов, снижение поверхностного стока и подземного питания, приводящие к сокращению площади и глубин озер, к снижению уровня воды, заилению, заболачиванию, эвтрофированию и загрязнению. На основе анализа космоснимков в Лаишевском районе выявлено более 170 озер площадью от 0,006 до 92,8 га. Основная группа озер относится к очень малым, с площадью до 1 га (101 озеро), в силу чего они очень уязвимы к антропогенному воздействию. Проблема деградации озер показана на примере озера Банновское в пос. Усады. Для озера Банновское характерно понижение уровня, сокращение площади, заиление, снижение качества воды, загрязнение вод нефтепродуктами, АПАВ и тяжелыми металлами, потеря рекреационной и хозяйственной ценности. Для озера рекомендованы профилактические и восстановительные мероприятия., Laishevsky district of the Republic of Tatarstan, adjacent to the city of Kazan, is currently being actively built up. The consequences of anthropogenic impact are a reduction in the area of catchments, a decrease in surface runoff and groundwater supply, leading to a reduction in the area and depth of lakes, a decrease in water levels, siltation, waterlogging, eutrophication and pollution. Based on the analysis of satellite images in the Laishevsky district, more than 170 lakes with an area of 0.006 to 92.8 hectares were identified. The main group of lakes is very small, with an area of up to 1 ha (101 lakes), which makes them very vulnerable to anthropogenic impact. The problem of lake degradation is shown by the example of Lake Bannovskoye in the village . Usada. Bannovskoye Lake is characterized by a decrease in the level, a reduction in the area, siltation, a decrease in water quality, water pollution with petroleum products, APAV and heavy metals, loss of recreational and economic value. Preventive and restorative measures are recommended for the lake., Международный научно-исследовательский журнал, Выпуск 5 (119) 2022, Pages 142-145

Lake Mogilnoe is a rare example of an anchialine lake (with subterranean connection to the ocean) in the Arctic, a refuge for landlocked populations of marine organisms. The lake has been the subject of intensive studies since the end of the 19th century. Here we demonstrate that between the 2003–07 and 2015–18 observation periods this permanently stratified lake experienced significant changes. The surface salinity increased and exceeded the tolerance limits of many freshwater organisms. The bottom anoxia expanded from one-fifth to one-third of the lake volume. Such a turn in stratification affected both composition and distribution of biota: freshwater zooplanktonic species virtually disappeared, while benthic communities shifted to shallower depths. Although recent changes in the lake stratification are consistent with the long-term trend, their scale is much larger than has been observed during the past 120 years. It was earlier considered that the lake dynamics were mainly affected by human activity in the vicinity of the lake. However, lack of human activity around Mogilnoe during last decades persuades us to search for the natural causes of the recorded changes.

Shorebird populations, especially those feeding on shellfish, have strongly declined in recent decades and identifying the drivers of these declines is important for conservation. Changing food stocks are thought to be a key driver of these declines and may also explain why trends have not been uniform across Europe's largest estuary. We therefore investigated how winter population trends of Eurasian oystercatchers (Haematopus ostralegus) were linked to food availability in the Dutch Wadden Sea. Our analysis incorporated two spatial scales, a smaller scale focused on roost counting areas and food available to birds in these areas and a larger spatial scale of tidal basins. A novelty in our study is that we quantify the connectivity between roosting and foraging areas, identified from GPS tracking data. This allowed us to estimate food available to roosting birds and thus how food availability may explain local population trends. At the smaller spatial scale of roost counting areas, there was no clear relationship between available food and the number of roosting oystercatchers, indicating that other factors may drive population fluctuations at finer spatial scales. At the scale of tidal basins, however, there was a significant relationship between population trends and available food, especially cockle Cerastoderma edule,. Mortality and recruitment alone could not account for the large fluctuations in bird counts, suggesting that the site choice of wintering migratory oystercatchers may primarily drive these large fluctuations. Furthermore, the relationship between oystercatcher abundance and benthic food stocks, suggests winter shorebird counts could act as ecological indicators of ecosystem health, informing about the winter status of food stocks at a spatial scale of tidal basins.

Highlights • The invertebrate biodiversity across 261 lakes in the Lake Taihu basin was studied. • The α diversity was consistent with the intermediate disturbance hypothesis. • Significant cross-taxon congruence was found between zooplankton and zoobenthos. • Zoobenthos were more sensitive to nutrient increases compared with zooplankton. • Eutrophication causes biodiversity loss and decreases cross-taxon congruence. Eutrophication is a major problem currently impacting many surface water ecosystems. Impacts of increased nutrient concentrations on biodiversity may differ between different scales, different organism groups, and different trophic states. Surveys at different spatial scales have suggested that biodiversity of different taxa may exhibit significant cross-taxon congruence. In our study, we examined the diversity of zooplankton and zoobenthos across 261 lakes in the Lake Taihu watershed, an area that is undergoing a severe eutrophication process. We tested the cross-taxon congruence in species richness and Shannon-Wiener diversity between zooplankton and zoobenthos along a nutrient gradient across the lakes. Our findings were consistent with the intermediate disturbance hypothesis, considering nutrient input as the disturbance. Also, we found significant cross-taxon congruence between zooplankton and zoobenthos diversities. Our results confirmed that excess nutrient levels resulted in diversity loss and community simplification. Zoobenthos were more sensitive to nutrient increases compared with zooplankton, which decreased cross-taxon congruence because these organism groups did not respond similarly to the anthropogenic disturbance.

The paucity of data on non-indigenous marine species is a particular challenge for understanding the ecology of invasions and prioritising conservation and research efforts in marine ecosystems. Marenzelleria spp. are amongst the most successful non-native benthic species in the Baltic Sea during recent decades. We used stable isotope analysis (SIA) to test the hypothesis that the dominance of polychaete worm Marenzelleria arctia in the zoobenthos of the Neva Estuary after its invasion in the late 2000s is related to the position of this species in the benthic food webs. The trend towards a gradual decrease in the biomass of Marenzelleria worms was observed during 2014–2020, probably due to significant negative relationships between the biomass of oligochaetes and polychaetes, both of which, according to SIA, primarily use allochthonous organic carbon for their production. The biomass of benthic crustaceans practically did not change and remained very low. The SIA showed that, in contrast to the native crustacean Monoporeia affinis, polychates are practically not consumed either by the main invertebrate predator Saduria entomon, which preys on M. affinis, oligochaetes and larvae of chironomids or by benthivorous fish that prefer native benthic crustaceans. A hypothetical model for the position and functional role of M. arctia in the bottom food web is presented and discussed. According the model, the invasion of M. arctia has created an offshoot food chain in the Estuary food webs. The former dominant food webs, associated with native crustaceans, are now poorly developed. The lack of top-down control obviously contributes to the significant development of the Marenzelleria food chain, which, unlike native food chains, does not provide energy transfer from autochthonous and allochthonous organic matter to the upper trophic levels. The study showed that an alien species, without displacing native species, can significantly change the structure of food webs, creating blind offshoots of the food chain.

Agricultural nonpoint source pollution is a critical issue that causes eutrophication in water bodies, due to the application of fertilizers. The traditional rice-fish coculture systems may develop a novel sustainable agriculture. The present study was undertaken to understand the ecological mechanisms of integrated fish farming especially water chemistry, dynamics of plankton, and benthic populations and their community compositions. In the rice-fish coculture system (RF), the total nitrogen in the water was higher compared to the rice monoculture system (RM), but significantly lower than in conventional fertilized rice farming. Dissolved oxygen (DO) presented a significant “Month x Treatment” interaction (p

Purpose. Creation of a thematic bibliographic list of publications on the use of classical and modern methods for studying the biota of water bodies - bacterio-, phyto-, zooplankton, zoobenthos, higher aquatic plants. Methods. The complete and selective methods were applied in the process of the systematic search. The bibliographic core have been formed with the publications exclusively in Ukrainian and Russian from the fund of scientific library of the Institute of Fisheries NAAS of Ukraine. Results. A thematic list of publications with a total quantity of 150 sources covering the time interval from 1949 to 2017, and devoted to the development and application of methods for studying aquatic biocenoses, their individual components and productive characteristics has been composed. The literary sources are arranged in alphabetical order by author or title, and described according to DSTU 8302:2015 “Information and documentation. Bibliographic reference. General principles and rules of composition”, with the amendments (code UKND 01.140.40), as well as in accordance with the requirements of APA style — international standard of references. Practical value. The list may be useful for scientists, practitioners, students, whose area of interests covers the questions of hydrobiology, hydroecology, zoology and aquaculture.

The Veselovskoe reservoir is among the most productive reservoirs of the Manych Cascade. Sharp changes in the hydrological and hydrochemical conditions of aquatic animals' habitat have been typical for the reservoir since its formation. During the intensive succession processes taking place in the reservoir, a restructuring of the plankton and benthos communities was observed accompanied by significant fluctuations in their quantitative indicators. In 2016, there were conducted complex hydrological and biological studies of the reservoir in order to assess the structure of phytoplankton, zooplankton and zoobenthos at the present stage. The western part of the reservoir as the most productive was studied in the autumn by applying standard techniques. According to the data obtained, the phytoplankton abundance averaged 198.1 mln cells/m3, and their biomass constituted 149.1 mg/m3 in the region under discussion, with diatoms and cryptophytes dominating in the phytoplankton community. The abundance of zooplankton averaged 15,298 ind./m3, and its biomass was 42.3 mg/m3. Rotifers dominated in the zooplankton by number, while cladocera and copepods played a key role in the biomass. The zoobenthos number and biomass amounted, respectively, to 3,141 ind./m2 and 7.4 g/m2, the basis of the benthic fauna of the reservoir was formed by oligochaetes and chironomids, whose abundance was predominant, as well as by mollusks that predominated in biomass. Studies of recent decades have revealed a decrease in the phytoplankton and zooplankton biomass in the Veselovsky reservoir. After the successful acclimatization of benthic invertebrates of the Caspian estuary complex and the penetration into the reservoir and development of invasive species, primarily the Dreissena, the abundance and biomass of the bottom community have stabilized and are maintained at a high level due to the malacofauna development

The rate at which biological diversity is altered on both land and in the sea, makes temporal community development a critical and fundamental part of understanding global change. With advancements in trait‐based approaches, the focus on the impact of temporal change has shifted towards its potential effects on the functioning of the ecosystems. Our mechanistic understanding of and ability to predict community change is still impeded by the lack of knowledge in long‐term functional dynamics that span several trophic levels. To address this, we assessed species richness and multiple dimensions of functional diversity and dynamics of two interacting key organism groups in the marine food web: fish and zoobenthos. We utilized unique time series‐data spanning four decades, from three environmentally distinct coastal areas in the Baltic Sea, and assembled trait information on six traits per organism group covering aspects of feeding, living habit, reproduction and life history. We identified gradual long‐term trends, rather than abrupt changes in functional diversity (trait richness, evenness, dispersion) trait turnover, and overall multi‐trait community composition. The linkage between fish and zoobenthic functional community change, in terms of correlation in long‐term trends, was weak, with timing of changes being area and trophic group specific. Developments of fish and zoobenthos traits, particularly size (increase in small size for both groups) and feeding habits (e.g. increase in generalist feeding for fish and scavenging or predation for zoobenthos), suggest changes in trophic pathways. We summarize our findings by highlighting three key aspects for understanding functional change across trophic groups: (a) decoupling of species from trait richness, (b) decoupling of richness from density and (c) determining of turnover and multi‐trait dynamics. We therefore argue for quantifying change in multiple functional measures to help assessments of biodiversity change move beyond taxonomy and single trophic groups., In this study, we identified gradual long‐term trends in functional diversity, trait turnover, and overall multi‐trait community composition spanning a period of 40 years and two key trophic groups: fish and zoobenthos, in three coastal marine areas. The study highlights the need for multiple measures and cross‐trophic level assessments to understand empirical functional (trait) change and serves as a baseline for functional change in the Baltic Sea region and other coastal and estuarine ecosystems worldwide. The findings contribute to the general understanding of biodiversity change and can be useful for developing predictions and models of community change.

Biodiversity of aquatic organisms is formed under the influence of not only natural, but also anthropogenic factors. In this work, the influence of the flow velocity, river size, flow regulation and urbanization on various groups of aquatic organisms was studied in several lowland rivers. The study was conducted in 2013 on six tributaries of the Upper Sukhona River. Five sampling sites were in different parts of the Vologda River and five sites on small rivers, Losta, Lukhta, Komya, Chernyj Shingar, and Belyj Shingar (one site per river). Phytoplankton, zooplankton and zoobenthos were sampled six times, from April to October, and macrophytes were studied in August. In total, 469 species of aquatic organisms were found in the tributaries of the Upper Sukhona River, belonging to the following phyla: Cyanophyta (5 species), Chrysophyta (8), Bacillariophyta (62), Xanthophyta (1), Cryptophyta (10), Dinophyta (4), Euglenophyta (12), Chlorophyta (17), Streptophyta (1), Bryophyta (2), Marchantiophyta (3), Equisetophyta (1), Magnoliophyta (63), Rotifera (22), Cnidaria (1), Platyhelmintes (1), Annelida (29), Mollusca (33), Arthropoda (194). The maximum number of species was found in the Vologda River, the largest of all the tributaries. The number of zoobenthos species was similar at different sites in the Vologda River and in the small rivers. The number of species of other groups of aquatic organisms in the small rivers was lower than those registered in the Vologda River. The greatest number of macrophyte and zoobenthos species was recorded in the Upper Vologda River and Belyj Shingar River, where the flow is strong all the year round. The greatest number of phyto- and zooplankton species was found at the extra-city sites where current is almost absent. In the dam backwater, species richness was higher than that registered downstream of the dam. At the same time, the species richness of macrophytes and zoobenthos in the dam backwater was lower. The smallest number of species was found in the Vologda River, downstream of the city of Vologda. Decreases in the species richness and Shannon’s biodiversity index were witnessed in the Vologda River city site and in the small rivers, as they get closer to the city. Cluster analyses performed for the studied groups of aquatic organisms showed dissimilar results; however, the studied sites on the Vologda River having the highest anthropogenic load formed a cluster. Aquatic organisms of the Upper Sukhona tributaries experience both natural (flow velocity and size of the watercourse) and anthropogenic factors (proximity to the city and flow regulation).

Understanding the impact of the environment on temporal trends in the composition and abundance of deep-sea species is essential for forecasting evolution of the community in the context of climate change. The recent development of deep-sea observatories enables multidisciplinary studies of long duration and high temporal resolution. We used a platform at the Ocean Networks Canada NEPTUNE Observatory located in the axis of Barkley Canyon between June 2012 and January 2015 to: (1) characterize the megabenthic community and the environmental conditions in the canyon; (2) investigate temporal patterns in the faunal community; and (3) determine the influence of environmental conditions on the observed patterns. The megafaunal epibenthic community, which included commercially important species, was composed of species known to be able to adapt to low oxygen conditions. A strong seasonal pattern characterized wind speed and direction, wave height, temperature, and chlorophyll concentration at the sea surface. The megafaunal epibenthic community exhibited seasonal patterns which were influenced by in-situ benthic boundary layer currents and temperature, weather conditions and chlorophyll concentration at the sea surface. At inter-annual scales, the surface temperature anomaly event observed in 2013 in the region could potentially impact the community structure with significant changes in species’ densities, highlighting the need for long-term monitoring in the region.

1. Growing bioeconomy is increasing the pressure to clear-cut drained peatland forests. Yet, the cumulative effects of peatland drainage and clear-cutting on the biodiversity of recipient freshwater ecosystems are largely unknown. 2. We studied the isolated and combined effects of peatland drainage and clear-cutting on stream macroinvertebrate communities. We further explored whether the impact of these forestry-driven catchment alterations to benthic invertebrates is related to stream size. We quantified the impact on invertebrate biodiversity by comparing communities in forestry-impacted streams to expected communities modelled with a multi-taxon niche model. 3. The impact of clear-cutting of drained peatland forests exceeded the sum of the independent effects of drainage and clear-cutting, indicating a synergistic interaction between the two disturbances in small streams. Peatland drainage reduced benthic biodiversity in both small and large streams, whereas clear-cutting did the same only in small streams. Small headwater streams were more sensitive to forestry impacts than the larger downstream sites. 4. We found 11 taxa (out of 25 modelled) to respond to forestry disturbances. These taxa were mainly different from those previously reported as sensitive to forestry-driven alterations, indicating the context dependence of taxonomic responses to forestry. In contrast, most of the functional traits previously identified as responsive to agricultural sedimentation also responded to forestry pressures. In particular, taxa that live temporarily in hyporheic habitats, move by crawling, disperse actively in water, live longer than 1 year, use eggs as resistance form and obtain their food by scraping became less abundant than expected, particularly in streams impacted by both drainage and clear-cutting. 5. Synthesis and applications. Drained peatland forests in boreal areas are reaching maturity and will soon be harvested. Clear-cutting of these forests incurs multiple environmental hazards but previous studies have focused on terrestrial ecosystems. Our results show that the combined impacts of peatland drainage and clear-cutting may extend across ecosystem boundaries and cause significant biodiversity loss in recipient freshwater ecosystems. This information supports a paradigm shift in boreal forest management, whereby continuous-cover forestry based on partial harvest may provide the most sustainable approach to peatland forestry.

Changes in benthic macrofaunal communities are indicative of environmental stressors, including eutrophication and hypoxia. However, some species are sensitive not only to hypoxia but also to various environmental contaminants. We tested which of the environmental predictors (sediment organic carbon, sediment concentrations of metals and polyaromatic hydrocarbons [PAHs], bottom water oxygen, salinity, temperature, and surface chlorophyll-a concentration) that best explained the following response variables: (1) macrofauna community composition, (2) abundance of a benthic sentinel species, the amphipod Monoporeia affinis; and (3) the Benthic Quality Index (BQI). All data originated from 29 reference monitoring stations in the Baltic Sea and the statistical tests included both uni- and multivariate analyses. The community composition and BQI were best explained by the same combination of salinity, depth, temperature and PAH concentrations. The abundance of M. affinis, which is sensitive to hypoxia and chemical exposure, was best explained by PAHs as a single predictor. Our findings suggest that benthic communities in the Baltic Sea are influenced by anthropogenic contaminants, which should be taken into account when benthos is used for eutrophication status assessment.

Simple Summary Examination of preferences of an aquarium “Red Cherry” shrimp for differently coloured backgrounds revealed common traits, irrespective of shrimp body colouration. The shrimp selected dark backgrounds and coarse patterns over light and fine patterned substrata. Thus, the use of materials with dark and uniform colouration can contribute to designing proper monitoring tools to detect biological invasions after releasing this pet into the wild, as well as to provide shrimp with comfortable conditions in captivity. Abstract An ornamental freshwater shrimp, Neocaridina davidi, is popular as an aquarium hobby and, therefore, a potentially invasive species. There is a growing need for proper management of this species to determine not only their optimum breeding conditions, but also their ability to colonise novel environments. We tested habitat preferences of colour morphs (brown, red, white) of N. davidi for substratum colour (black, white, grey shades, red) and fine or coarse chess-board patterns to recognise their suitable captivity conditions and predict their distribution after potential release into nature. We conducted laboratory choice experiments (n = 8) with three individuals of the same morph exposed for two hours to a range of backgrounds. Shrimp preferred dark backgrounds over light ones irrespective of their own colouration and its match with the background colour. Moreover, the brown and red morphs, in contrast to the white morph, preferred the coarse background pattern over the finer pattern. This suggests that the presence of dark, uniform substrata (e.g., rocks, macrophytes) will favour N. davidi. Nevertheless, the polymorphism of the species has little effect on its total niche breadth, and thus its invasive potential.

Studies of the benthos in nearshore water areas within Protected Areas along the Black Sea are an important ecological task. In this connection, protected habitats can be recognised as intact natural areas, where the entire natural complex is preserved with its typical taxonomic structure and biodiversity features. This study is based on the obtained quantitative data on the biodiversity of benthic assemblages in coastal Protected Areas. It aims to study the structure of polychaete communities as inhabitants of fouling areas at sublittoral (depth 0–3 m) rocky/boulder substrates in four Protected Areas along the Black Sea (Cape Martyan State Nature Reserve, Karadag State Nature Reserve, Opukskiy State Nature Reserve, and Utrish State Nature Reserve). The studied sites differ in their geographic location, orographic shape of the coastal strip, features of underwater substrates, the pattern of spatial coverage and species composition of macroalgae foulings and other environmental parameters. The purpose of this study was also to make a prognostic estimation of the expected species richness (Sexp) and comparative analysis of the structural organisation of polychaete complexes on rocky substrates in the selected coastal Protected Areas. The prognostic modelling of polychaete species richness was based on the known extrapolation algorithms (estimators Chao-2, Jackknife-2, and bootstrap). The results show that the expected level of species richness (Sexp) exceeds the actually detected (Sobs) number of species in each of the four Protected Areas by 20–95%, depending on the estimator and total number of collected samples. In all sublittoral water areas, it was found that with an increase in the number of samples the accumulation curves do not reach a horizontal asymptote. This indicates an underestimated species richness of polychaetes. At the rocky sublittoral zone of the Cape Martyan State Nature Reserve, the fastest increase in Sexp values was revealed with an increase in the number of samples taken. This relationship can be determined by heterogeneity of microhabitats in this area, where the increased number of polychaete species is also formed. Considering the other Protected Areas, the extrapolative curves of species richness have a flatter mode and a smaller expected number of species (Sexp), despite the larger number of samples analysed. According to the results of the clustering and ordination analyses, based on the species composition and abundance of polychaetes, almost all samples taken were grouped into separate clusters corresponding to each of the four studied Protected Areas. The reliability of structural differences between polychaete complexes was statistically confirmed by pairwise comparison of three areas (Utrish, Karadag, and Martyan). The comparison of sites conditionally named Utrish and Opukskiy demonstrated that structural differences between polychaete complexes were statistically insignificant probably due to the affinity of the geomorphologic pattern of hard-bottoms and composition of fouling vegetation in sublittoral zones of both Protected Areas. The specific polychaete complexes have been formed on rocky/boulder substrates within each of the investigated Protected Areas, being different in their taxonomic structure and quantitative characteristics of the certain species. For each polychaete complex, the most significant species were identified, which determine both the intracomplex taxonomic structure (indicating species) and structural differences between the complexes (discriminating species). In the polychaete complex of the rocky sublittoral in the Karadag State Nature Reserve such indicating species were Nereis zonata, Platynereis dumerilii, and Syllis gracilis. In the Cape Martyan State Nature Reserve and Utrish State Nature Reserve, the indicating taxa were Polyophthalmus pictus, Nereis sp., and Pholoe inornata. Finally, in the Opukskiy State Nature Reserve, Notomastus latericeus and Pholoe inornata were recognised as indicating species. Most of these species may also be considered as discriminating species. Parameters of their quantitative development reflect the structural features of polychaete complexes formed under the influence of specific environmental factors in the sublittoral zone of each of the four studied coastal Protected Areas. The obtained results of the structural-faunistic analysis of polychaete complexes can be applied for comparative assessment of the biodiversity features of benthic communities during the comprehensive ecological monitoring of the coastal Protected Areas.

Highlights • We compared fungi, invertebrates and diatoms in model-based stream bioassessment. • Fungal models virtually equaled the overall best model in precision and accuracy. • Fungi were superior in identifying streams degraded by multiple stressors. • Results strongly support the use of microbial communities in stream bioassessment. Degradation of freshwater ecosystems requires efficient tools for assessing the ecological status of freshwater biota and identifying potential cause(s) for their biological degradation. While diatoms and macroinvertebrates are widely used in stream bioassessment, the potential utility of microbial communities has not been fully harnessed. Using data from 113 Finnish streams, we assessed the performance of aquatic leaf-associated fungal decomposers, relative to benthic macroinvertebrates and diatoms, in modelling-based bioassessment. We built multi-taxon niche -type predictive models for fungal assemblages by using genus-based and sequence-based identification levels. We then compared the models’ precision and accuracy in the prediction of reference conditions (number of native taxa) to corresponding models for macroinvertebrates and diatoms. Genus-based fungal model nearly equalled the accuracy and precision of our best model (macroinvertebrates), whereas the sequence-based model was less accurate and tended to overestimate the number of taxa. However, when the models were applied to streams disturbed by anthropogenic stressors (nutrient enrichment, sedimentation and acidification), alone or in combination, the sequence-based fungal assemblages were more sensitive than other taxonomic groups, especially when multiple stressors were present. Microbial leaf decomposition rates were elevated in sediment-stressed streams whereas decomposition attributable to leaf-shredding macroinvertebrates was accelerated by nutrients and decelerated by sedimentation. Comparison of leaf decomposition results to model output suggested that leaf decomposition rates do not detect effectively the presence of multiple simultaneous disturbances. The rapid development of global microbial database may soon enable species-level identification of leaf-associated fungi, facilitating a more precise and accurate modelling of reference conditions in streams using fungal communities. This development, combined with the sensitivity of aquatic fungi in detecting the presence of multiple human disturbances, makes leaf-associated fungal assemblages an indispensable addition in a stream ecologist’s toolbox.

Background. The study of the fish feed base of the Khatanga River is necessary due to the fact that the river is used for commercial fishing of valuable fish species. The last description of the communities of zooplankton and zoobenthos of the Khatanga River was carried out according to the data of 1946, respectively, there is no more up-to-date information about the state of hydrobiological communities. The aim of this work is to establish the taxonomic composition and quantitative characteristics of zooplankton and zoobenthos communities, as well as to assess the trophic status of the Khatanga River. Materials and methods. Studies of the river were conducted at 5 stations: in 2014-in the areas of the settlements of Novorybnoye and Kresty, in 2015-at 25 km, 45 km and 67 km from the mouth of the river, in 2018-2020-in the area of the settlement of Khatanga. Samples of zooplankton and zoobenthos were collected and processed according to the methods generally accepted in Russian hydrobiology. All samples were taken in three repetitions. Results, conclusions. During the 2014–2015 and 2018– 2020 studies, 33 taxa were identified in zooplankton, and 37 in zoobenthos. The average values of zooplankton abundance and biomass ranged from 57±57 to 477±441 ind./m3 and from 0.52±0.52 to 3.12±0.64 mg/m3, respectively, and zoobenthos – from 260 to 2642 ind./m2 and from 0.65 to 4.04 g/m2, respectively. Rotifers were dominant in the zooplankton community in terms of quantitative parameters, while chironomids, oligochaetes, and mollusks were dominant in the zoobenthos. According to the development of zooplankton and zoobenthos, the river belongs to the "low-feed" fishing facilities. The trophic category of the Khatanga River is defined as "ultra – oligotrophic" by zooplankton, and "α-mesotrophic" by zoobenthos.

В рамках данной работы рассматриваются результаты мониторинговых исследований, проводимых специалистами ООО «Азово-Черноморский научный центр рыбохозяйственных исследований» в период января-декабря 2020 г. по изучению видового состава и численности организмов зообентоса на периодически затапливаемых участках акватории Краснодарского края в пределах ст-цы Старокорсунская Краснодарского края В результате исследований изучено видовое разнообразие, получены сезонные и годовые показатели численности и биомассы организмов зообентоса на периодически затапливаемых участках акватории Краснодарского водохранилища. Проведена сравнительная характеристика данных характеристик с показателями, характерными для постоянно обводненных участков акватории Краснодарского водохранилища., Within the framework of this work, the results of monitoring studies carried out by specialists of the Azov-Chernomorsk Scientific Center for Fisheries Research in the period January-December 2020 to study the species composition and number of zoobenthos organisms in periodically flooded areas of the Krasnodar Territory water area within the Starokorsunskaya station are considered. Krasnodar Territory. As a result of the research, the species diversity was studied, seasonal and annual indicators of the abundance and biomass of zoobenthos organisms were obtained in periodically flooded areas of the Krasnodar reservoir. A comparative characteristic of these characteristics with the indicators typical for constantly watered areas of the Krasnodar reservoir is carried out.

International audience; Few studies have focused on the trophic functioning of the reservoirs in Algeria. The study of the gut contents of fish species, as well as the analysis of the stable isotopes of 13C and 15N in the environment, were carried out on samples collected during spring 2010 in two reservoirs: Ghrib and Harreza of the upper Cheliff plain (Algeria) within a semi-arid climate zone. In each of the reservoirs, 13C and 15N were measured in sediments, particulate organic matter (POM), macrophytes, zooplankton, zoobenthos and fish. The isotopic analysis shows that the carbon values that supply both reservoirs, Ghrib and Harreza, were −31.16 ± 0.05 < 13C < −18.01 ± 0.21‰ and −30.82 ± 0.07 < 13C < −17.24 ± 3.50‰, respectively. The carnivorous fish Sander lucioperca, and Abramis brama, an omnivorous fish, were allocated to the top of the food web in Ghrib and Harreza reservoirs, respectively. In the latter, a reservoir with low hydrodynamism and depth, the food web is simpler with a single fish species, which benefits from both benthic and pelagic sources. In Ghrib, a deeper dam with stronger hydrodynamics, only the riverine crab Potamon algeriense exploits the benthic sources, whereas fish mainly feed on zooplankton.

Coastal areas are known to receive significant anthropogenic inputs, mainly deriving from metropolitan areas, industries, and activities related to tourism. Among these inputs, some trace elements are listed as priority pollutants in the European Water Framework Directive, due to their ability to bioaccumulate in organisms. Many studies have been conducted on heavy metals (HMs) accumulation and on their possible effects on different edible marine species. While the most studied sessile organisms are bivalves, in the current review, we focus our attention on other sessile taxa (sponges, cnidarians, bryozoans, polychaetes, cirripeds, and tunicates), proposed as bioindicators in coastal shallow waters. Although their potential as bioindicator tools has been repeatedly highlighted in the literature, these organisms are still poorly investigated and considered for monitoring. In this context, we analyze the available literature about this topic, in order to summarize the current knowledge and identify possible applications of these organisms in a bioremediation scenario.

Впервые по результатам изучения ихтиофауны, основных групп гидробионтов, слагающих кормовую базу (фитопланктон, зоопланктон, зообентос), проведено описание и анализ качественных и количественных характеристик зооценоза в верхнем и среднем течении реки Пшеха. Установлена общая закономерность в распределении фитопланктона, зоопланктона и зообентоса в реки Пшеха. Определена средняя численность и биомасса организмов. Установлен видовой состав ихтиофауны рассматриваемых участков реки. Рассчитана средняя плотность распределения рыб. Материалы проведенных исследований представляют как научный фаунистический интерес, так и несут практическое значение в изучении рационального природопользования водных ресурсов в условиях антропогенного воздействия., Based on the results of studying the ichthyofauna, the main groups of aquatic organisms that make up the food base (phytoplankton, zooplankton, zoobenthos), the current article for the first time provides a description and analysis of the qualitative and quantitative characteristics of the community of living organisms in the upper and middle reaches of the Pshekha River in Krasnodar Krai. The study establishes a general pattern in the distribution of phytoplankton, zooplankton, and zoobenthos as well as determines the average number and biomass of organisms in the Pshecha River. The author of the research defines the species composition of the ichthyofauna of the sections of the river under study and calculates the average density of fish distribution. The materials of the conducted research are of both scientific faunal interest and present practical importance in the study of the rational use of water resources in the conditions of anthropogenic impact., Международный научно-исследовательский журнал, Выпуск 3 (105) 2021, Pages 33-36

В работе приводятся результаты исследований состава зообентосных сообществ озера Прорва (Западно-Казахстанской область, Казахстан). За период исследовании выявлено 27 таксонов донных беспозвоночных из 6 классов. Анализируются показатели численности и биомассы гидробионтов, по составу и структуре зообентоса вычислены индексы разнообразия, сапробности и оценен уровень кормности озера., The paper presents the results of studies of the composition of zoobenthos communities of Prorva lake (West Kazakhstan region, Kazakhstan). During the study period, 27 taxa of benthic invertebrates from 6 classes were identified. The indices of the abundance and biomass of aquatic organisms are analyzed, the indices of diversity and saprobity are calculated according to the composition and structure of zoobenthos, and the level of feeding of the lake is estimated., Естественные и технические науки, Выпуск 4 (155) 2021

High-elevation tropical lakes are excellent sentinels of global change impacts, such as climate warming, land-use change, and atmospheric deposition. These effects are often correlated with temporal and spatial beta diversity patterns, with some local communities contributing more than others, a phenomenon known as local contribution to beta diversity (LCBD) or ecological uniqueness. Microorganisms, such as diatoms, are considered whole-ecosystem indicators, but little is known about their sensitivity and specificity in beta diversity studies mostly because of the lack of large spatial and temporal datasets. To fill this gap, we used a tropical South American diatom database comprising modern (144 lakes) and paleolimnological (6 sediment cores) observations to quantify drivers of spatial and temporal beta diversity and evaluated implications for environmental change and regional biodiversity. We used methods of beta diversity partitioning (replacement and richness components) by determining contributions of local sites to these components (LCBDrepl and LCBDrich), and studied how they are related to environmental, geological, and historical human variables using Generalized Additive Models (GAM). Beta replacement time series were also analyzed with GAM to test whether there is widespread biotic homogenization across the tropical Andes. Modern lake ecological uniqueness was jointly explained by limnological (pH), climatic (mean annual precipitation), and historical human density. Local lake (conductivity) and regional geodiversity variables (terrain ruggedness, soil variability) were inversely correlated to replacement and richness components of LCBD, suggesting that not all lakes contributing to broad-scale diversity are targets for conservation actions. Over millennial time scales, decomposing temporal trends of beta diversity components showed different trajectories of lake diatom diversity as response of environmental change: i) increased hydroclimatic variability (as inferred by decreased temperature seasonality) mediating higher contribution of richness to local beta diversity patterns ca. 1000 years ago in Ecuador Andean lakes and ii) lake-specific temporal beta diversity trends for the last ca. 200 years, indicating that biotic homogenization is not widespread across the tropical Andes. Our approach for unifying diatom ecology, metacommunity, and paleolimnology can facilitate the understanding of future responses of tropical Andean lakes to global change impacts.

Background. Zoobenthos is an essential component of the fish food base. Therefore, an assessment of fish productivity for this indicator is necessary for any comprehensive fisheries research in water bodies. The purpose of the study was to study the seasonal dynamics of zooplankton development to determine fish productivity by this indicator of one of the sections of the river Sura. Materials and methods. Zoobenthos samples were taken in the studied reservoir at three points of the selected station in the middle of the month of the ice-free period from April to November, 2014–2015. (and in May, 2016). Fishery products were calculated taking into account coefficients adapted to the Volga region. A comparative analysis with neighboring reservoirs (the natural channel of the Sura River and the Penza River, a sand pit) was carried out according to the results of our own research. Results. During the study period, 52 taxa of macrozoobenthos were identified (in 2014 – 27, in 2015 – 35). Changes in the species composition of zoobenthos over the years amounted to 65 %. The monthly changes in the species composition in different years turned out to be close on average (38 and 41 %, respectively). In numbers, bivalve mollusks, small-worm worms, and diptera insect larvae dominated in different months. By biomass – bivalves and gastropods, small-worms. In 2014, the monthly zoobenthos abundance varied by 1,2–2,5 times, and the biomass by 0,9–3,0 times. In 2015, the monthly abundance of zoobenthos differed 1,1–5,9 times, and biomass 1,4–3,9 times. The differences between the monthly indices by years in terms of numbers were 1,2–3,7 times, and in biomass 1,1–2,7 times. On average, between years the abundance of zoobenthos in 2014 was 1,2 times higher than in 2015, and in biomass 1,2 times lower without Anodontastagnalis. In seasonal and interannual dynamics, the state of zoobenthos in the Gorodskoye reservoir is estimated as quite stable. Conclusions. In the City Reservoir there is a free food base for zoobenthos and it can be stocked with valuable species of benthophagous fish (carp) to increase fish stocks and meet the needs of amateur fishermen of the city of Penza. The highest indices of zoobenthos biomass were observed in 2015 in the spring period (April, May). Indicators close to the seasonal average were recorded in all other months of the ice-free period.

The species composition and structure of zooplankton and zoobenthos were studied in the Komi Republic’s oldest small storage reservoir, which has operated continuouslysince 1758. Over the period from 2007 to 2017, 85 species and forms of zooplankton and 21 taxonomic groups of benthic invertebrates were identified. At the initial stage of the research, as the water level in the reservoir was stable and the growth of aquatic macrophytes was minor, the reservoir’s planktic and benthic communities was stable in the species composition and quantities. Lowering of the water level promoted the reservoir’swater trophicity, triggered a rise in the taxonomic abundance and quantities of zooplankton and zoobenthos, a change of the communities’ leading groups, and a reduction in the composition of the dominant complexes. When the water level was boosted up after the restoration of the Kazhimsky hydroelectric installations was over, a vast shore area wasflooded, modifying the reservoir’s ecological status. Changes in aquatic invertebrate communities included a decrease in the quantitative indicators of development, a reduction in the number of taxa and species diversity, alteration of the dominant complexes.

Проведены гидробиологические исследования по определению состояния донных организмов рек бассейна Алдана в зоне деятельности Куранахского золоторудного месторождения. Сравнение показателей состояния бентоса в фоновых и загрязненных участках показало, что с ухудшением среды обитания во всех трофических звеньях гидробиоценоза происходят значительные изменения в количественном составе, качественном развитии и структуре зообентоса., Hydrobiological studies were carried out to determine the status of bottom organisms of the rivers of the Aldan basin in the area of operation of the Kuranakh gold ore deposit. Comparison of indicators of the state of benthos in the background and contaminated areas showed that with a deterioration of the environment in all trophic links of hydrobiocenosis, signifi cant changes occur in the quantitative composition, qualitative development and structure of zoobenthos., №9(135) (2020)

The aim of this work was to evaluate the food base (zooplankton, zoobenthos and aerial insects) and production results in culture of two-year-old golden ide (Leuciscus idus aber. orfus) and chub (Squalius cephalus). The specifics of the study were to use the attractants (yellow plates) and submersed lights as a supplement to the nutrition of farmed fish. Experimental rearing took place in the earth ponds in the area of Experimental Fish Culture Facility in Vodňany (Czechia) and in the storage ponds in Schlossfischerei Schönau bei Litschau (Austria). Zooplankton composition and physico-chemical parameters were monitored during regular two-week sampling periods. Monitoring of zoobenthos and terrestrial insects captured by attractants was performed at monthly intervals. Macrozoobenthos was sampled by Ekman Grab. After processing the samples in the laboratory, the benthic invertebrates were divided into three groups - Chironomidae, Oligochaeta and Varia. Zooplankton was collected by planktonic mesh in the 3 m long hauling and divided into the fraction of small zooplankton (Daphnidae < 499 micrometre, Copepoda < 999 and > 1000 micrometre and Others - small Cladocera), and into the fraction of coarse zooplankton (Daphnidae 500 - 999, Daphnidae 1000 - 1499 and > 1500 micrometre). Terrestrial insects were captured by installed attractants for a specified time period of day (colour attractants) or night (light attractants). The results show that the environmental conditions of the monitored ponds did not differ significantly. Abundance of coarse zooplankton in both experimental cultures was influenced by fish. The density of zoobenthos did not differ significantly. However, the values in the ponds with the lights were higher than in the control. According to the analysis of growth and production data, the installation of insect attractants as a supplementary measure to fish nutrition in aquaculture seems to be beneficial for production results. The average weight of golden ide increased during the growing season from the initial 4,3 g to 26,9 +- 4,9; 32,3 +- 6,5 and 41,2 +- 9,2 g in control ponds, ponds using lights and yellow plates, respectively. The differences between both control and experimental treatments as well as between lights and yellow plates were highly significant (p < 0,001). In the culture of chub using light attractants, the average fish weight increased from the initial 12,7 g to 41,9 +- 2,2 g, respectively to 26,7 +- 5,5 g in control. In both treatments, the production was analogously higher.

Concentration of neurotoxin Hg (mercury) was determined monthly form 01.2012 to 05.2013 (total and suspended) in the surface microlayer and the surface water as well as in: phytoplankton, zooplankton, epilithon, epifithon, phytobenthos (macroalgae and angiosperms), zoobenthos, and in the sediment. The study was conducted in the coastal zone of the Puck Lagoon (Osłonino and Chałupy) and the Gulf of Gdańsk (Gdynia). Mercury data were compiled with the abundance and biomass of individual species of: phytoplankton, phytobentos, zoobenthos; abundance of individual species of zooplankton; water temperature; salinity; pH; suspended particulate matter concentration; concentration of particulate organic carbon and nitrogen (in the surface microlayer and the surface water); δ13C and δ15N in the suspended matter; sediment parameters like: moisture, fine sediment fraction, LOI and redox condition. Results indicate influence of warming of cold season (from late autumn to early spring) on Hg concentration in biotic and abiotic components of marine coastal zone. Increase annual average mercury concentration in trophic web of gulf.

A decline in the density of zoobenthos has taken place in Lake Abiskojaure in the northern Swedish mountains between 1988 and 2019 but no response can be seen in the abundance (CPUE) of Arctic charr (Salvelinus alpinus) that feed mainly on benthic invertebrates. To evaluate if possible shifts in resource use of charr explain this lack of change in population abundance, stomach contents (i.e. diet) of charr between 1985 and 2020 were analyzed. Charr diets changed during the study period, with decreasing contributions to the diet of larger sized prey and increasing contribution of smaller sized prey and zooplankton. A corresponding recent decline in charr growth, size, and condition factor was observed. The proportion of large prey in diets and charr growth both show a hump-shaped relationship with time before the recent decline, indicating consumption of large prey had a positive effect on charr growth. Densities of zooplankton in the lake did not change with time, meaning increases in diet proportions are driven by something else. Declines in nitrogen and phosphorous over time may have contributed to the decline in zoobenthos densities through nutrient limitation of primary production. The results from this study suggest charr has changed diet towards smaller, less energetically efficient prey as a response to declining zoobenthos levels, and that this has had a negative effect on charr growth, size, and condition factor. Additional declines in nutrients and zoobenthos abundance may further worsen charr performance and eventually be manifested as declining charr abundance.

The results of long-term complex hydrobiological studies of the cooling pond of the South Ukrainian Nuclear Power Plant (SU NPP) are presented. The abundance of zoo- and phytoplankton increased until 1984–1985, and then in the summer of 1986, against a background of extremely high temperatures in the reservoir, there was a significant (32-fold) drop in the mean biomass of phytoplankton, coinciding with the minimum abundance of zooplankton. In subsequent years, the abundance of these groups recovered, but has not reached previous levels. At present, the zooplankton contains a considerable amount of thermophilic species. Research in recent years indicates that the zooperiphyton is dominated by the invasive gastropods Melanoides tuberculata (Müller, 1774) and Terebia granifera (Lamarck, 1822). In the epiliton, the number of LDT (lowest determined taxa) and groups of invertebrate was more than double that in the epiphyton (17 and 7, respectively). At the first stages of the development of the pond ecosystem, the periphyton communities were dominated by zebra mussel Dreissena polymorpha Pall. These communities were eliminated as temperature increased, and after the commissioning of the NPP, the second and third power units were not completely restored in the environment of a constantly high thermal load. Over years, with the formation of bottom biotopes, the abundance of zoobenthos increased, and with an increase in the technogenic load, it decreased. At the present stage, the zoobenthos is impoverished (9 taxa) and is dominated by mainly juvenile tubificids.

Biotic interactions are fundamental drivers governing biodiversity locally, yet their effects on geographical variation in community composition (i.e. incidence‐based) and community structure (i.e. abundance‐based) at regional scales remain controversial. Ecologists have only recently started to integrate different types of biotic interactions into community assembly in a spatial context, a theme that merits further empirical quantification. Here, we applied partial correlation networks to infer the strength of spatial dependencies between pairs of organismal groups and mapped the imprints of biotic interactions on the assembly of pond metacommunities. To do this, we used a comprehensive empirical dataset from Mediterranean landscapes and adopted the perspective that community assembly is best represented as a network of interacting organismal groups. Our results revealed that the co‐variation among the beta diversities of multiple organismal groups is primarily driven by biotic interactions and, to a lesser extent, by the abiotic environment. These results suggest that ignoring biotic interactions may undermine our understanding of assembly mechanisms in spatially extensive areas and decrease the accuracy and performance of predictive models. We further found strong spatial dependencies in our analyses which can be interpreted as functional relationships among several pairs of organismal groups (e.g. macrophytes–macroinvertebrates, fish–zooplankton). Perhaps more importantly, our results support the notion that biotic interactions make crucial contributions to the species sorting paradigm of metacommunity theory and raise the question of whether these biologically‐driven signals have been equally underappreciated in other aquatic and terrestrial ecosystems. Although more research is still required to empirically capture the importance of biotic interactions across ecosystems and at different spatial resolutions and extents, our findings may allow decision makers to better foresee the main consequences of human‐driven impacts on inland waters, particularly those associated with the addition or removal of key species.

Ongoing climate change is increasing the occurrence and intensity of drought episodes worldwide, including in boreal regions not previously regarded as drought prone, and where the impacts of drought remain poorly understood. Ecological connectivity is one factor that might influence community structure and ecosystem functioning post‐drought, by facilitating the recovery of sensitive species via dispersal at both local (e.g. a nearby habitat patch) and regional (from other systems within the same region) scales. In an outdoor mesocosm experiment, we investigated how impacts of drought on boreal stream ecosystems are altered by the spatial arrangement of local habitat patches within stream channels, and variation in ecological connectivity with a regional species pool. We measured basal ecosystem processes underlying carbon and nutrient cycling: (a) algal biomass accrual; (b) microbial respiration; and (c) decomposition of organic matter, and sampled communities of aquatic fungi and benthic invertebrates. An 8‐day drought event had strong impacts on both community structure and ecosystem functioning, including algal accrual, leaf decomposition and microbial respiration, with many of these impacts persisting even after water levels had been restored for 3.5 weeks. Enhanced connectivity with the regional species pool and increased aggregation of habitat patches also affected multiple response variables, especially those associated with microbes, and in some cases reduced the effects of drought to a small extent. This indicates that spatial processes might play a role in the resilience of communities and ecosystem functioning, given enough time. These effects were however insufficient to facilitate significant recovery in algal growth before seasonal dieback began in autumn. The limited resilience of ecosystem functioning in our experiment suggests that even short‐term droughts can have extended consequences for stream ecosystems in the world‘s vast boreal region, and especially on the ecosystem processes and services mediated by algal biofilms.

Дана краткая характеристика исследованных малых рек Краснодарского края и их рыбохозяйственная категорийность. Впервые по результатам изучения основных групп гидробионтов (фитопланктон, зоопланктон, зообентос, рыбы) проведено описание и анализ качественных и количественных характеристик зооценозов малых рек Краснодарского края. Приводятся сведения о среднегодовых биомассах фитопланктона, зоопланктона, зообентоса. Представлены сведения о видом составе ихтиофауны малых рек, их потенциальной рыбопродуктивности и продуктивности нерестилищ. Исследование ихтиофауны представляет как научный фаунистический интерес, так и несет практическое значение в изучении и сохранении биологического разнообразия в условиях мощного антропогенного воздействия., The author provides a brief description of studied small rivers of the Krasnodar Krai and gives their fishery categories. The description and analysis of the qualitative and quantitative characteristics of zoocenoses of small rivers in the Krasnodar Territory are given for the first time, based on the results of the study of the main groups of aquatic organisms (phytoplankton, zooplankton, zoobenthos, fish). The author also provides information on the average annual biomasses of phytoplankton, zooplankton, and zoobenthos. The data on the ichthyofauna species composition in small rivers, their potential fish productivity, and the productivity of spawning grounds are presented as well. The study of ichthyofauna is of both scientific interest and of practical value in the study and conservation of biological diversity under conditions of powerful anthropogenic impact., Международный научно-исследовательский журнал, Выпуск 10 (100) 2020

Lake littoral environments are heterogeneous, and different organisms typically show specific responses to this environmental variation. We examined local environmental and spatial factors affecting lake littoral biodiversity and the structuring of assemblages of phytoplankton, zooplankton and macroinvertebrates within and among three basins of a large lake system. We explored congruence of species composition and species richness among the studied organism groups to evaluate their general indicator potential to represent spatial variation in other groups. We expected that effects of water chemistry on plankton assemblages were stronger than effects of habitat characteristics. In contrast, we anticipated stronger effects of habitat on macroinvertebrates due to their mainly benthic mode of life. We also expected that within-basin spatial effects would be strongest on macroinvertebrates and weakest on phytoplankton. We predicted weak congruence in assemblage composition and species richness among the organism groups. Phytoplankton assemblages were mainly structured by the shared effects of water chemistry and large-scale spatial factors. In contrast to our expectations, habitat effects were stronger than water chemistry effects on zooplankton assemblages. However, as expected, macroinvertebrate species composition and richness were mainly affected by habitat conditions. Among-group congruence was weak for assemblage composition and insignificant for richness. Albeit weak, congruence was strongest between phytoplankton and zooplankton assemblages, as we expected. In summary, our analyses do not support the idea of using a single organism group as a wholesale biodiversity indicator.

В статье представлены результаты изучения влияния антропогенных факторов городской агломерации на жизнь зообентоса озер Белое, Сайсары, Теплое, Талое, Хатынг-Юрях, Сергелях и Атласовские Якутска. Показано, что городские озера различаются между собой по видовому разнообразию. Максимальное число видов с численностью 184 экз/м2 и биомассой 40,24 г/м2 определено в озере Белое. Основными систематическими группами в исследуемых озерах были пиявки, бокоплавы и хирономиды (67 %), которые относятся к организмам умеренно-загрязненных и грязных вод. Результаты исследования зообентоса озера Хатын — Юрях, расположенный на северо-восточной части Якутска, определили как с бедной бентофауной, всего тремя систематическими группами организмов — пиявки, бокоплавы и личинки двукрылых. Массовыми по численности оказались бокоплавы (236 экз/м2), а по биомассе пиявки (22,08 г/м2). При этом большинство организмов относились к трем классам качества вод, а состояние озер оценили как — «чрезвычайно грязное». Нами определенный анализ состояния зообентоса городских озер указывает об устойчивом антропогенном воздействии города Якутска на экосистемы всего бассейна в целом., The article presents the results of teaching the studies of the impacts of anthropogenic factors of agglomeration on the life of the zoobenthos of the lakes Beloe, Saisary, Teploe, Taloe, Khatyng-Yuryakh, Sergelyakh and Atlasovskie in Yakutsk. It is shown that these urban lakes differ in their types of diversity. The maximum number of species with a number of 184 ind./m2 and a biomass of 40.24 g/m2 was found in Lake Beloe. The main systematic groups in the studied lakes were polluted leeches, amphipods and chironomids (67 %), which belong to the organisms of moderately polluted and dirty waters. The results of the study of the zoobenthos of Lake Khatyn — Yuryakh, located in the northeastern part of the city of Yakutsk, were identified as having a poor benthic fauna: only 3 systematic groups of organisms, i.e. leeches, amphipods and dipteran larvae. Amphipods (236 ind./m2) turned out to be massive in terms of numbers, and leeches in terms of biomass (22.08 g/m2). Moreover, most of the organisms belonged to three classes of water quality, and the state of the lakes was assessed as “extremely dirty”. We have determined that the analysis of the state of the zoobenthos in urban lakes indicates a stable anthropogenic impact of the city of Yakutsk on the ecosystems of the entire basin as a whole.

Представлен обзор опубликованных материалов о влиянии вселенца Dreissena polymorpha Pallas на экосистему Нарочанских озер (Беларусь). Показана динамика развития популяции моллюска-вселенца в озерную экосистему, его роль в составе малакофауны и значимость как средообразующего фактора. Оценен вклад дрейссены в круговорот взвешенных, органических и биогенных веществ и влияние моллюска на ранний диагенез донных отложений.

Current state of zoobenthos in the areas of scallop Chlamys islandica beds in the southern Barents Sea and eastern White Sea (Voronka) is described. The scallop stock is ex­ploited there with the landing by specialized vessels, without separation of catch, so bycatch of other species is considerable. As the result, significant changes occurred in structure of benthic communities during the times of scallop fishery. To assess the fishery effect, species composition of benthos, its dominant species and trophic structure is considered separately for 4 regions with different degree of exploitation. Dynamics of zoobenthos abundance is traced over the last 25 years. Changes in trophic structure of the benthic community at Cape Svyatoy Nos (southern Barents Sea) are analyzed in details. Although up to ¼ of its total biomass is presented by carnivorous species and the biomass of C. islandica has decreased, the portion of sestonophages has increased in this community. Recently a recovery of zoob­enthos is observed in its southern part, supposedly because of the animals redistribution from adjacent areas unaffected by fishery. On the contrary, extremely low biomass of zoobenthos, in particular scallop, is observed in the northern part of the community. Biomass of benthos in the Voronka area is high, but it is formed mainly by mussels. There is concluded that more than a decade is required for full recovery of the scallop stock and accompanying zoobenthos communities to the native state.