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Tidal flat ecosystems, are under steady decline due to anthropogenic pressures including sea level rise and climate change. Monitoring and managing these coastal systems requires accurate and up-to-date mapping. Sediment characteristics and macrozoobenthos are major indicators of the environmental status of tidal flats. Field monitoring of these indicators is often restricted by low accessibility and high costs. Despite limitations in spectral contrast, integrating remote sensing with deep learning proved efficient for deriving macrozoobenthos and sediment properties. In this study, we combined deep-learning features derived from Sentinel-2 images and Object-Based Image Analysis (OBIA) to explicitly include spatial aspects in the prediction of tsediment and macrozoobenthos properties of tidal flats , as well as the distribution of four benthic species. The deep-learning features extracted from a convolutional autoencoder model were analysed with OBIA to include spatial, textural, and contextual information. Object sets of varying sizes and shapes based on the spectral bands and/or the deep-learning features, served as the spatial units. These object sets and the field-collected points were used to train the Random Forest prediction model. Predictions were made for the tidal basins Pinkegat and Zoutkamperlaag in the Dutch Wadden Sea for 2018 to 2020. The overall prediction scores of the environmental variables ranged between 0.31 and 0.54. The species-distribution prediction model achieved accuracies ranging from 0.54 to 0.68 for the four benthic species). There was an average improvement of 21% points on predictions using objects with deep learning features compared to the pixel-based predictions with just the spectral bands. The mean spatial unit that captured the patterns best ranged between 0.3 ha and 13 ha for the different variables. Overall, using both OBIA and deep-learning features consistently improved the predictions, making it a valuable combination for monitoring these important environmental variables of coastal regions. [ABSTRACT FROM AUTHOR]

A river-lake system plays an important role in water management by providing long-term and frequent water diversions. However, hydrological connectivity in the system can have a profound effect on sediment microbial communities through pH, nutrient concentrations, and benthos invertebrates. Consequently, identifying the key environmental factors and their driving mechanisms is vital for microbial adaptation strategies to extreme environments. In this study, we analyzed the significant difference in sediment bacterial and fungal community structures and diversity indices among Dongting Lake and its tributary rivers, which worked as a typical river-connected lake ecosystem. There were significant differences in biotic and abiotic environments in the sediment habitats of Dongting Lake and its tributary rivers. Random forest analysis revealed that pH and Mollusca were found to be the most important abiotic and biotic variables for predicting both bacterial and fungal community structures, respectively. The beta diversity decomposition analyses showed that the bacterial and fungal community compositional dissimilarities among different sections were dominated by species replacement processes, with more than half of the OTUs in each section being unique. Notably, both biotic and abiotic factors affected the number and the relative abundance of these bacterial and fungal unique OTUs, leading to changes in community composition. Mollusca, pH, TP, NO3-N, and NH4-N were negatively related to the relative abundance of Actinobacteria, Acidobacteria, Gemmatimonadetes, Planctomycetes, and Ascomycota, while Annelida and ORP were positively related to the relative abundance of Actinobacteria and Gemmatimonadetes. Additionally, PICRUSt analysis revealed that the functional dissimilarity among lakes and rivers was strengthened in unique species compared to all species in bacterial and fungal communities, and the changes of functional types helped to improve the habitat environment in the main Dongting Lake and promote the process of microbial growth. From our results, the role of macrozoobenthos and physicochemical characteristics in driving the sediment microbial community spatial variations became clear, which contributed to further understanding of the river-lake ecosystem. [ABSTRACT FROM AUTHOR]

Non-indigenous invasive topmouth gudgeon (Pseudorasbora parva) was introduced to Europe in 1960s and it has passed an ongoing invasion into many European countries. It forms numerous populations particularly in pond aquaculture systems and small stagnant water bodies. The study was carried out on a 0.3 ha pond inhabited solely by the population of topmouth gudgeon. Monthly samplings of environmental variables, zooplankton, macrozoobenthos and fish were performed in 2016–2017. Topmouth gudgeon recruitment correlated with decrease of oxygen concentration and transparency in summer months, apparently due to topmouth gudgeon predation on the cladocerans. The macrozoobenthos community was dominated by large chironomid larvae (Chironomus plumosus), whose density and biomass were not affected by the topmouth gudgeon population. The habitat preferences varied within the population. The 0 + age cohort were abundant in rocky rip-rap, muddy and macrophyte habitats with low abundance in free water zone. In contrast, the 1 + and older fish significantly preferred the rocky rip-rap habitat and free water zone over muddy and macrophyte substrates. In spring, the rocky rip-rap was occupied mainly by males, while later in June and July, females predominated in this habitat. The study also documented disapperance of topmouth gudgeon population due to sudden spate flash-flood. [ABSTRACT FROM AUTHOR]

The main structural characteristics of the summer macrozoobenthos of the Rybinsk Reservoir have been studied according to the data of the expanded grid of stations in 2019 and 2021. Eighty species and forms of benthic invertebrates are identified, most of which are chironomids, oligochaetes, and mollusks. In all zones and parts of the reservoir, the basis of benthos species richness is represented by chironomids. The dominant complex on all soils includes Limnodrilus hoffmeisteri Claparede, 1862, in most cases Chironomus f. l. plumosus, with the exception of silted sand, where Cladotanytarsus gr. mancus and Tubifex newaensis (Michaelsen, 1902) are added to them. On the silted-up shell, the dominants include Potamothrix moldaviensis Vejdovsky et Mrazek, 1902. The basis of the quantity (93%) and biomass (86%) of animals is chironomids and oligochaetes. The greatest abundance of benthic invertebrates is recorded on gray silts and in the deepwater zone of the reservoir. The Sheksninsky part is characterized by the largest benthic biomass, and the Volzhsky part by the largest quantity. Among the trophic groups in the quantity of macrozoobenthos on all main soils, in all parts, in the deepwater zone and estuarine areas of the tributaries of the reservoir, the basis is formed by detritophages–swallowers. In the zone of open shallow water, phytodetritophages–filtrators + collectors dominate in quantity. This trophic group makes the greatest contribution to the benthic biomass of gray and peaty silts, in all zones and parts, except the Volzhsky part. On silted-up shell, the largest share in the total biomass is made up of phyto-detritophages–filtrators + collectors and detritophages–swallowers. Detritophages–swallowers form the main part of benthic biomass on silted sand and in the Volzhsky part. When conducting a comparative analysis with the results obtained in 1978, a decrease in the biomass of oligochaetes on gray silts is recorded by ~3 times. Likely, this is due to a decrease in the occurrence and abundance of a large oligochaete that previously dominated on gray silts, an indicator of β-mesosaprobic conditions, Tubifex newaensis. In 2019 and 2021, this oligochaete was not included in the dominant complex of gray silts. It began to be represented by polysaprobes Limnodrilus hoffmeisteri. This can serve as an indirect sign of an increase in the trophic status of a reservoir to a typically eutrophic one and an increase in the accumulation of organic matter in soils. [ABSTRACT FROM AUTHOR]

The findings of 2019 research on bottom biocenoses in several macrophyte beds around Lake Ladoga are presented. The spatial distribution of macrozoobenthos quantitative properties indicate significant variances. Zoobenthos biomass and density ranges from 0.17 to 77.13 g/m2 and 392–49 800 specimen/m2, respectively. In terms of biomass, amphipods dominate the taxa (on average, 49%). Compared with 2014, by 2019 there was a decline in the zoobenthos level of development. The Gmelinoides fasciatus,Micruropus possolskii, Pontogammarus robustoides, and Chelicorophium curvispinum invasive amphipod species are demonstrated to significantly influence the interannual alterations of macrozoobenthos communities in the lake's littoral zone. [ABSTRACT FROM AUTHOR]

The article summarizes and analyzes the published data and results of our own research on nonindigenous species (NIS) of aquatic invertebrates and fish and pathways of their penetration and further distribution in the Belarusian part of the Neman River basin. There are 18 established NIS of aquatic invertebrates and fish up to date: 8 NIS of macroinvertebrates and 10 NIS of fish. It was shown that the main way for invasion of aquatic invertebrates was canals. The main way for invasion of fish was intentional introduction for the purpose of fishing. The list of potential nonindigenous species of aquatic invertebrates and fish that can be introduced in the near future is given. [ABSTRACT FROM AUTHOR]

This study presents the findings of a case study investigating the seasonal dynamics (spring vs. autumn) of macroinvertebrates, microplastic particle abundance, and sediment composition in the benthos of the Vrapčak urban stream in Zagreb, Croatia, at two sites: upstream (V1) and downstream (V2). The abundance of macroinvertebrates remained constant between seasons, but taxa such as Chironomidae, Ephemeroptera, Diptera pupae and Simuliidae showed significant seasonal variation. The dominance of Chironomidae and Oligochaeta supports the urban stream syndrome hypothesis, where tolerant species increase and sensitive species decrease. Sediment analysis revealed a uniform mineral composition in both seasons with an average carbonate content of 52.8%. The analysis of microplastics revealed that the number and mass of particles at site V1 were almost twice as high as at site V2. In spring, site V1 recorded 12 microplastic particles ranging from 0.5 to 5 mm in size, while site V2 recorded 13 particles. In autumn, V1 had 13 particles, whereas V2 had 19 particles, with V1 showing overall higher concentrations. These variations between sites and seasons may be influenced by site-specific environmental factors, such as differences in flow conditions. The predominant microplastic types were Polyethylene (32%), Polystyrene (28%) and Ethylene Vinyl Acetate (17%). It is noteworthy that 12% of the particles could not be classified, which is likely due to environmental degradation and illustrates the difficulties in identifying microplastics. While no significant differences were found between sites in physico-chemical parameters, seasonal variations were observed in water temperature, flow velocity and nutrient concentrations. This case study highlights the need for standardized microplastic sampling methods and continuous monitoring to manage the dynamic and pollutant-prone urban stream ecosystems. The integrated approach (e.g., combining FTIR microplastics analyses with ecological methods) is promising to understand and mitigate the impacts of urbanization on freshwater environments. [ABSTRACT FROM AUTHOR]

The present study aims to detect early changes in the community structures of macrozoobenthos and indications of their recovery following sand excavation activities in the soft bottom of the southern continental shelf area, Korea strait, from August 2002 to October 2005. About 10 million m3 of relict sandy sediments were excavated from a 9 km2 area over 18 months, from June 2002 to April 2004. The sand excavation and collection activities in the study area increased the sand amount in the residual sediments due to the complete loss of fine surface sediments. However, the fine particles in the turbidity flumes produced by sand hopper vessels were deposited in neighboring zones. The overall ecological impacts of the sand excavation activity are the rapid loss of macrobenthic animals in the central region of the excavation area and the decrease in densities of some disturbance-sensitive macrobenthos, such as Ampelisca spp. and Photis longicaudata that are dominant in the marginal parts of the excavation area. The burrowing polychaete Ophelina acuminata and the opportunistic tube-building polychaete Paraprionospio coora were the most predominant species in the central region of the study area following 12 months. The affected regions showed decreases in the abundance and recovery of the macrozoobenthic fauna species depending on the changes in sediment properties induced by the sand excavation activities, such as sediment loss and material deposition materials. One and a half years after the cessation of the sand excavation activities, the density of the most abundant species was increased and comparable to those in the reference area. In addition, the biological characteristics of the macrobenthic community showed indications of recovery to their previous status, with different faunal compositions and densities. Further long-term ecological monitoring of the macrobenthic communities is necessary to comprehensively assess their recovery processes following sand excavation in the study area. [ABSTRACT FROM AUTHOR]

Protecting rivers and lakes from pollution is crucial for maintaining the health of aquatic ecosystems and ensuring the well-being of both wildlife and humans. Present study intends to examine the water quality of the Suna River (Eastern Fennoscandia in the European North of Russia) to assess the ecological risk. Widespread methods for assessing water quality based on macrozoobenthos and phytoperiphoton were applied. It was found that in conditions of ultra-fresh waters with high humus content, biotic indicators may indicate pollution of water bodies that do not actually experience significant anthropogenic impact. Ratings ranging from ‘poor’ to ‘excellent’ were obtained for different stations, reflecting the influence of natural features of different sections of the river. ‘Good’ water quality was noted at the river stones biotopes. In river gravel, sand and silt biotopes, as well as all lake biotopes, ‘mediocre’ water quality was found. The low anthropogenic income on the river catchment allows us to conclude that most indices for assessing water quality significantly underestimate the results in the natural conditions of Eastern Fennoscandia. Biotic indices EPT, BBI and EBI are most accurate for assessing the water quality of rivers and lakes in Eastern Fennoscandia. HIGHLIGHTS An assessment of the ecological state of the freshwater ecosystem in the North of Russia has been carried out.; Macrozoobenthos and periphyton can be indicators of the state of the environment.; The anthropogenic factor is important in the formation of a high-quality aquatic environment.; Water quality is determined by the degree of the impact on the ecosystem.; Very low water mineralization and high humus content make it difficult to determine the ecological status of rivers and lakes.;

Lake Blagodatnoye is an oligohaline meromictic reservoir with the two-layer vertical structure — a typical lagoon lake for the southern Far East of Russia. Its upper layer is occupied by fresh water and the lower layer — by brackish water. The greatest warming of water (up to 22 оC) is observed at the lake surface in late July — early August. In total, 274 species are found in phytoplankton of the lake that is the largest number among all surveyed lagoon lakes in the south of Sakhalin-Kuril region. Bacillariophyta form the basis of the phytoplankton species composition (64 % of species). Abundance and biomass of the phytoplankton vary widely from 1.15 . 106 to 160.44 . 106 cells/L and from 0.41 to 6.14 g/m3, respectively. Several peaks are noted in seasonal dynamics of these indices. Zooplankton in the lake includes 25 species. All these species are typical for lagoon lakes in the south of Sakhalin-Kuril region. Wide variations in abundance and biomass are noted for the zooplankton: from 10550 to 99350 ind./m3 and from 47.1 to 231.0 mg/m3, respectively. Two types of species composition are identified in the summer succession of the phytoand zooplankton communities. The phytoplankton groups change at the border between June and July, when temperature at the surface passes the value of 14–16 оC. The key species of the early-summer phytoplankton are Cyanobacteria of genera Aphanocapsa, Chroococcus, Microcystis, Anabaena and Bacillariophyta of the genus Asterionella, whereas Aulacoseira granulata and A. granulata var. angutissima are the most abundant in late summer. For zooplankton, the boundary between the early-summer and late-summer seasons is shifted to middle July when the water temperature rises to 17–18 оC. Rotifera of Asplanchna priodonta, Cladocera of Bosmina sp., younger copepodites of Cyclops and Eurytemora caspica tethysiana dominate in early summer, whereas Bosmina sp. and juveniles of Cyclops — in late summer. Macrozoobenthos in the lake is represented by 25 species of invertebrates. The basis of species diversity is formed by amphibiotic insects. Number of species and total distribution density and biomass of macrozoobenthos mostly declined with the depth: there were 18 species, 370 ± 50 ind./m2, 3.023 ± 0.459 g/m2 in the intertidal zone, 14 species, 580 ± 59 ind./m2, 3.477 ± 0.447 g/m2 in the elittoral zone, and 10 species, 364 ± 36 ind./m2, 2.110 ± 0.248 g/m2 in the profundal zone, and dominant species were changed from Amphipoda Eogammarus barbatus in the intertidal zone to Chironomidae Chironomus dorsalis in the elittoral zone and to Gastropoda Cincinna japonica, Oligochaeta Lumbriculus variegatus and Chironomidae C. dorsalis in the profundal zone. The phytoplankton production in the coastal zone (depth of 0–3 m) was estimated as 552.86 kcal/m2 in June-August. Zooplankton consumed only 0.7 % of this production and produced 767 cal/m2. The production of non-predatory zoobenthos was 8644 cal/m2, with the inputs of 70.2 % for detritus feeders of 70.2 %, 11.8 % for macroalgae feeders, 11.6 % for deposit feeders, 5.8 % for grazers, and 0.6 % for filtered suspension feeders. A part of this production (6.9 %) was transmitted to the feed of carnivorous zoobenthos, so 8286 cal/m2 of the macrozoobenthos production could be used for fish feeding in the coastal zone. The phytoplankton production in the open waters (depth of 3–9 m) was estimated in 2580 kcal/m2. Zooplankton consumed 1.01 % of this production and produced 3578 cal/m2. The production of non-predatory zoobenthos in this zone was 6179 cal/m2 (detritus feeders 68.1 %, deposit feeders 18.8 %, grazers 6.6 %, macroalgae feeders 3.0 %, and filtered suspension feeders 3.5 %). The portion of 12.7 % of this production was transmitted to the feed of carnivorous zoobenthos. The total macrozoobenthos production in the open waters was 5708 cal/m2. The total reserve of food for fish, including zooplankton and benthos, was evaluated in 9286 cal/m2.

Representative sets of biotic and abiotic parameters were taken from maps of their distribution at the sea bottom, using interpolation. Good correspondence between real and modeled data was noted that allowed to engage the latter for correct estimation of the mean explained variance (MEV) by regression analysis. The magnitude and structure of MEV variability depended on external influence that proves possibility of its application as a measure for total effect of abiotic factors. Among many variants of the ecological stress index (PES), the more convenient for modeling was that one with the maximum correlation between distribution density or biomass of certain taxa and the total density or biomass of macrozoobenthos at stations (in samples). This approach provides better biological plausibility, as well, so as the benthic dwellers, like other animals, are very diverse in size and interspecific relations, that’s why the distribution density of a species correlates well with either total density or total biomass, and the same for biomass of a species. Results of in situ studies of PES dependence on MEV were confirmed by modeling with virtual MEV values. The difference between real and modeled PES values was statistically insignificant, but the MEV ranged wider in the models with virtual values and the dependence curve had weaker inflection when reached a plateau. The final dependence is S-shaped (r2 = 0.939), with the greatest curvature at 85.4 % of MEV (PES of 15 %), and the point of minimum or beginning of growth (beginning of the model curve plateauing) at 94.0 % of MEV (PES of 36 %). These levels are critical for macrozoobenthos communities. The PES level for the 2nd critical level was previously estimated as 30 %, but this value was corrected to 36 % by calculation with biologically more reasonable method.

This article provides a scientific study on the macrozoobenthos communities in two lakes in Russia, specifically Lake Bannoe and Lake Kholmovskoe. The research aims to compare the macrozoobenthos in these lakes, which are both facing similar human impact. The study was conducted in 2022, and samples were collected and analyzed using standard methods. The article presents information on the taxonomic composition, density, and biomass of the macrozoobenthos in Lake Bannoe. Additionally, the article evaluates the water quality of the lakes using various indices. The study concludes that Lake Bannoe is moderately polluted, while Lake Kholmovskoe has relatively clean waters. This research is part of larger projects focusing on the ecosystem of the Northern Dvina River and the Solovetsky Archipelago. [Extracted from the article]

The results of studies of bottom biocenoses in three types of littoral zone (rocky biotope, gravel-sand biotope, and surf zone with thickets of higher aquatic vegetation) of Lake Onego in 2013 and 2014 are presented. Our data show that, among the three types of coastal zone, the macrozoobenthos biomass is maximal in the rocky littoral zone (3.4–6.6 g/m2) and is minimal in the sandy zone (0.1–0.2 g/m2). The invasive species Gmelinoides fasciatus (Stebbing 1899) (CRUSTACEA: AMPHIPODA) has successfully naturalized in all types of littoral zones of the reservoir in recent decades. This species dominates both in number and biomass in the rocky type of biotope. [ABSTRACT FROM AUTHOR]

This article presents the results of a comprehensive study of two components of the aquatic biocenosis: its floristic component and benthos in the shallow waters of the Gorky Reservoir within the water area of the Yaroslavl State Nature Reserve. The composition and structure of plant communities at the boundary of the macrophyte belt is assessed, followed by the identification of dominant associations. At the same time, the taxonomic composition and quantitative characteristics of macrozoobenthos are assessed in the main plant biotopes. Plant communities in the water area are represented by two ecological groups: helophytes and hydrophytes. Macrophytes occupy up to 25% of the water area of the shallow area of the studied water body. Most of the plant communities are concentrated in the northern and northeastern parts of the reserve. Eleven species of macrophytes belonging to 10 genera and 9 families are noted. In macrophyte communities, eight typical associations were identified where benthos sampling are carried out. In the benthos of typical macrophyte associations, 35 lower definable taxa (LDT) are identified, of which 17 LDT are chironomid larvae. In the biotope, 11 LDT are found out of vegetation. The highest species richness of benthic invertebrates is noted in the communities of Butomus umbellatus L. (1753) and Sparganium erectum L. The benthos of plant communities in August 2021 can be characterized as chironomid–oligochaete, while chironomids dominate in the open littoral. Mollusks play a significant role in the formation of benthos in plant communities. The maximum quantitative indicators of benthic invertebrates in general—and the abundance of chironomids of the genus Glyptotendipes, in particular—have been noted in the community of the burr Sparganium erectum. This is probably due to the morphological structure of this plant and the specifics of the formation of the community by this species. The benthos of plant communities is dominated by phytodetritophages–filterers and phytodetritophages–filterers + gatherers, while phytodetritophages–filterers prevail in the open littoral. There are no detritophages–gatherers in any of the studied biotopes. In general, according to the abundance of macrozoobenthos, the areas of plant communities can be classified as high-nutrient and very high-nutrient. [ABSTRACT FROM AUTHOR]

This study aimed to represent threatened species of benthic invertebrates, at national and international level, in the rocky areas of the Adriatic Sea in Albania, and to highlight the causes of threats for these species. A total of 58 threatened species of benthic invertebrate were found in the study area, and four sites were selected for investigation: Shën Pjetër, Kallm, Spille, and Triport. A considerable number of these species has a high threatened status, including critically endangered species and vulnerable species. Three species found in the studied area are also threatened on an international scale. Environmental impacts in these areas are mainly related to water pollution and degradation of coastal habitats because of uncontrolled tourism development, as well as coastal erosion. The significant number of threatened species at the national level and the presence of threatened species on the international level highlighted the importance of the rocky shores of the Adriatic Sea in Albania, in terms of conservation and environmental management on the national and international scale. [ABSTRACT FROM AUTHOR]

Eutrophication, driven by excessive nutrient enrichment from sources like agricultural runoff, industrial discharge, and urbanisation, has severely impacted the Black Sea since the 1980s. This study aimed to assess eutrophication dynamics in the Romanian Exclusive Economic Zone from 2020 to 2022 using the Black Sea Eutrophication Assessment Tool (BEAST), an integrated approach to the causes and effects of eutrophication. Data were collected from 68 stations during five oceanographic expeditions, analysing 617 water samples for nutrients, chlorophyll a, zooplankton species Noctiluca scintillans, and dissolved oxygen. Additionally, 179 zoobenthic and 251 phytobenthic community samples were collected. The results indicate that coastal waters exhibit higher nutrient levels and algal blooms compared to offshore waters, necessitating significant reductions in nutrient concentrations to achieve good environmental status. In transitional waters, within the Danube Delta Biosphere Reserve, a 55% reduction in inorganic phosphorus and a 43% reduction in inorganic nitrogen concentrations are required, while coastal waters need reductions of 38% and 37%, respectively. The study highlights the need for improved wastewater treatment, stricter agricultural runoff controls, and continuous monitoring. Effective ecosystem-based management strategies, integrated coastal zone management, and international cooperation are essential to mitigate eutrophication and promote the long-term health of the Black Sea ecosystem. [ABSTRACT FROM AUTHOR]

Simple Summary: This study illustrates a baseline biodiversity snapshot of macrofauna inhabiting the seafloor in German marine protected areas (MPAs) if the North and Baltic Seas in 2020–2022, before the full closure for bottom-contact fishing. While the closure is now in place in some MPAs, it is still planned for the near future in others. The analyses included different habitats in nine Natura 2000 MPAs. We provide essential data and comprehensive macrofauna species lists per area, relevant for the joint future conservation efforts and effective management. We explore environmental drivers of community structure and touch upon suggested effects of bottom-contact fishing in both geographic regions. Despite the expectation of more limited connectivity between MPAs in the Baltic Sea compared to the North Sea, the degree of community differentiation between MPAs was higher in the North Sea. Alpha diversity generally increased towards the open North Sea, and gamma diversity seemed comparable for these two regions. The Baltic Sea dataset unexpectedly contained a higher number of taxa, including Red List species. Achieving homogeneity of monitoring data and joint assessment even within one national program and biological compartment between different geographic regions, research institutions and fields remain challenging. This joint work appeals for flexible data sharing and prioritizing informal intersessional communication. Such a baseline is important for assessing future faunal changes. The response of benthic habitats and organisms to bottom-contact fishing intensity is investigated in marine protected areas (MPAs) of the German EEZ in the North and Baltic Seas. We examined the current state of macrofauna biodiversity in 2020–2022. Comparative analysis for macrofauna (in- and epifauna) inhabiting nine Natura 2000 MPAs constitutes a baseline to assess the effects of bottom-contact fishing exclusion in the future. Aspects of spatial and temporal variability are briefly summarized and discussed. We provide a species list for each region, including 481 taxa, of which 79 were found in both regions, 183 only in the North Sea, and 219 only in the Baltic Sea. The Baltic Sea dataset surprisingly included higher numbers of taxa and revealed more Red List species. The share of major taxonomic groups (polychaetes, bivalves and amphipods) in species richness showed peculiar commonalities between the two regions. In the North Sea, multivariate analysis of community structure revealed significantly higher within-similarity and stronger separation between the considered MPAs compared to the Baltic MPAs. Salinity, temperature and sediment fractions of sand were responsible for over 60% of the variation in the North Sea macrofauna occurrence data. Salinity, mud fraction and bottom-contact fishing were the most important drivers in the Baltic Sea and, together with other considered environmental drivers, were responsible for 53% of the variation. This study identifies aspects of macrofauna occurrence that may be used to assess (causes of) future changes. [ABSTRACT FROM AUTHOR]

The relationships between the hydrochemical and structural characteristics of the macrozoobenthos community, including biotic indices is analyzed in the rivers of the Neman basin in the spring and summer periods. The list of hydrochemical characteristics included pH, dissolved oxygen concentration, the concentration of ions of ammonium and nitrate nitrogen, dissolved phosphorus, and heavy metals. A close correlation was found to exist between the structural characteristics of zoobenthos and water hydrochemical composition; it can be clearly seen in the summer period. The maximal values of the correlation coefficients were obtained for the relationship between the shares of EPT and oligosaprobic species in the total number of macrozoobenthos. The correlation between the number of macrozoobenthos species and the hydrochemical characteristics was found to be unreliable. The importance of the multimetric approach, taking into account both the hydrobiological and hydrochemical characteristics was emphasized. [ABSTRACT FROM AUTHOR]

Analysis of macrozoobenthos samples collected in the reservoirs of the Western Manych River valley during a complex expedition organized by the Southern Scientific Center of the Russian Academy of Sciences in 2021, revealed two polychaete individuals from the genus Laonome. Probably, the polychaete Laonome xeprovala Bick & Bastrop, in Bick et al., 2018 invaded the Veselovskoye Reservoir via the cascade of waterways from the Don River. This is a new locality for this species within the invasive range of the genus on the territory of the Russian Federation. To date, since this polychaete has been revealed at only one sampling site, it is difficult to evaluate the level of naturalization of this species in the water bodies of the Western Manych valley. [ABSTRACT FROM AUTHOR]

Using the example of rivers in the Onega Lake basin, the species composition of mollusks of the Sphaeriidae family and their abundance, biomass, and contribution to benthic communities in rivers with many lakes in the catchment areas have been analyzed. Patterns of the spatial distribution of species across biotopes and gradients of environmental variables are traced. Twenty-six species of mollusks of this family are identified, with European–Siberian species predominating. Most species of mollusks of the family Sphaeriidae found by us have wide ecological ranges and are found in water bodies of various types. It is found that the contribution of Sphaeriidae to the species richness and functioning of aquatic communities in rivers in the conditions of branched lake–river systems (Lake Onega basin) exceeds the values usual for rivers with a small number of lakes in the catchment area. Using the ANOSIM and PERMANOVA methods, it is proven that the species composition of rocky rapids and riffles, sandy rifts, and soft bottom soils is different. Using the IndVal test, seven species are shown to have a statistically significant association with one of these biotopes, and four of them have a statistically significant association with the rocky bottoms of river rapids and riffles. Using the NMDS method, it is shown that the greatest changes in the species composition of representatives of Sphaeriidae are observed when environmental conditions change from small streams with a slow current and brown water to large rivers with a fast current and clear water. [ABSTRACT FROM AUTHOR]

Relationship between the environmental stress index (PES) and the mean total explained variance of biotic parameters (MEV, as a measure of the environmental factors influence on macrozoobenthic communities) is determined using the methods of multiple linear stepwise regression analysis and non-linear estimation. The relationship is S-shaped, with the points of beginning and end of linear growth confined to the PES ≈ 15–16 % and 30 %. These levels should be considered as boundary criteria for the status of macrozoobenthic communities. Under favorable environmental conditions, PES does not exceed 15 % (the first critical level), that is close to a «biologically balanced» state of the communities. The PES values in the range of 15–30 % indicate an increased influence of limiting factors, but this influence is not destructive. The PES values > 30 % (the second critical level) indicate extreme deterioration of habitat conditions and transition to a «physically controlled» state of the communities.

The study compares the structure of invertebrate communities inhabiting two types of bottom sediments in Krzynia Reservoir, known also as Lake Krzynia (on the Słupia River, northern Poland). The lake is prone to intensive sedimentation because it is limnic. This limnicity is due to the impact of the river, rather than to surface runoff from the catchment area, where the heavy predominance of natural habitats over transformed ones slows the transport of mineral suspensions from adjacent terrain. In the organic-poor sediments dominated by sand and gravel, the mean density of benthic invertebrates was ten-fold higher than in silty, organic-rich sediments, while invertebrate biomass was only slightly and non-significantly higher in organic-poor sediments than in organic-rich sediments. Simultaneously, the mean invertebrate body weight was markedly lower in organic-poor sediments (0.03 g) than in organic-rich sediments (0.18 g). No significant differences in taxonomic diversity (number and Shannon index of taxa) were found between the studied sediment types in the analysed communities. Among the major invertebrate groups, the Oligochaeta and Mollusca significantly differed in density between sediment types, while the Oligochaeta and Chironomidae differed in biomass. An increased percentage of silt fraction in bottom sediments resulted in a drastic decrease in abundance of benthic fauna, but their biomass declined only slightly. Thus, plans to construct new reservoirs should aim to reduce the rate of silt accumulation in them, in order to preserve their primary function and support biodiversity in transformed river valleys. [ABSTRACT FROM AUTHOR]

The Reuleng River is a mangrove area located in Aceh Besar district. Environmental changes that occur in the structure and composition of the mangrove ecosystem in the Reuleng River affect the macrozoobenthos conditions in the area. This study aims to determine the structure of the makrozoobenthos community as a biomomonitoring instrument in the mangrove ecosystem area. The study was conducted from February 2021 to May 2021. Determination of the sampling location was carried out using the purposive sampling technique and sampling was determined in three areas, namely upstream, middle stream, and downstream. The results showed that there were 19 species grouped into 4 genera and 12 families. The Macrozoobenthos Diversity Index in the Reuleng River area ranges from 2.62. The species that dominate the mangrove ecosystem area is the Faunus ater species with a dominant index value (0.16) and the lowest dominant species in the mangrove ecosystem is Thalassina anomala (0.01). No specific species were found that dominate the area. Based on descriptive observations, there is a group of Makrozoobenthos that has a relationship with the psychochemical quality of the air. The results show that the balance of the community in the area is still vulnerable and experiencing the impact of environmental pressures. [ABSTRACT FROM AUTHOR]

We used macrozoobenthos data (abundance, biomass, and community structure) spanning 69 years including annual surveys from 1997 to 2016 in three connected lakes with different trophic states located in the north-west of Belarus (lakes Naroch, Myastro, and Batorino) to investigate the relationships between Carlson's trophic state indices (TSI) and macrozoobenthos. We studied the response of the macrozoobenthos both over time and by depth zone. We found that there is an inverse relationship between lake productivity as measured by chlorophyll-based TSI and macrozoobenthos abundance and biomass both when comparing the three Narochianskie lakes and in the long-term dynamics within each lake. Lake-wide and littoral zone benthic biomass decreased significantly with increasing trophic state. Macrozoobenthos community structure also differed among lakes, with Chironomidae dominating in the most productive lake (Batorino), Chironomidae and Mollusca dominating in Lake Myastro, which had an intermediate trophic state, and Mollusca dominating in the lake with the lowest TSI (Naroch). We found significant differences both in the average benthos biomass and in the composition of macrozoobenthos between the profundal (silt and lack of macrophytes) and littoral zones (presence of macrophytes) within each lake. We argue that bottom substrates, macrophytes, and dreissenid mussels were more important for macrozoobenthos than trophic state in these lakes. Several benthic invertebrate taxa differed among lakes and are potential indicators of trophic state. [ABSTRACT FROM AUTHOR]

The benefit of this research is to understand macrozoobenthos diversity and its connection to mangrove density in Pagatan Besar Village. Determination of observation stations by purposive sampling method. Research on macrozoobenthos was carried out in a 10 m × 10 m mangrove vegetation observation transect. The results showed that the macrozoobenthos found consisted of 12 species, namely Polymesoda bengalensis, Uca lactea annulipes, Scylla serrata, Episesarma, Chicoreus capucinus, Cerithidea quoyii, Cassidula aurisfelis, Telescopium Telescopium, Ellobium aurisjudae, Calliostoma zizyphinum, Nerita lineata and Littoraria scabra. The macrozoobenthos density index from the three stations produced various values. The diversity index of the three stations belongs to the moderate diversity category (H' 1 < H' < 3.322). The uniformity index of Stations 2 and 3 is included in the high uniformity category (0.6 ≤ E ≤ 1.0) and Station 1 is included in the medium uniformity category (0.4 ≤ E < 0.6). The dominance index values of the three stations indicate that there are macrozoobenthos species that dominate at each station because the value of D > 0.5. The results of a simple correlation analysis of "Pearson Product Moment" between mangrove density and macrozoobenthos density produce a fairly weak relationship with mangrove density where the equation shows a negative value (-).

Land subsidence in intertidal environments may change the flooding regime and sediment composition, two drivers of the macrozoobenthic community. In the Dutch Wadden Sea, a UNESCO world heritage site, gas extraction has resulted in an average subsidence of intertidal mudflats of 2 mm year−1. These mudflats support an abundant macrozoobenthic community that offers important resources for birds and fish. The area is managed through the 'hand on the tap' principle, meaning that human activities should be halted if they affect the natural values. To what extent land subsidence affects sediment and macrozoobenthos remains unknown and is increasingly important given sea level rise.Taking advantage of a large‐scale monitoring program, we evaluated the effect of anthropogenically caused subsidence on sediment composition and macrozoobenthos. Nearly 4600 points were sampled yearly (2008–2020) across the Dutch Wadden Sea, allowing us to compare sediment composition and macrozoobenthos biomass within and outside the subsidence area while controlling for the main drivers of these variables. We also compared population trends within and outside the subsidence area for 31 species with different habitat use.Mud fraction was 3% higher within the subsided area and median grain size decreased at 1 μm year−1 while remaining constant in other mudflats. This had no effect on the total biomass of macrozoobenthos. Within the subsidence area, however, the biomass of species that use deeper areas increased compared to outside, and the opposite was true for species using shallower habitat.Policy implications: Land subsidence is related to changes in median grain size and macrozoobenthic community composition. However, because thresholds have not been defined, it is not clear if this requires management actions. For a successful implementation of the 'hand on the tap' principle in the Wadden Sea, it is necessary to define beforehand the relevant variables that represent the natural values, implement proper monitoring and define thresholds above which effects are not acceptable. We propose median grain size, mud fraction and macrozoobenthic composition as good measures of the natural values of the Wadden Sea, and the methods used here as a way for identifying anthropogenic effects on them. [ABSTRACT FROM AUTHOR]

Ecological restoration has become an important management-tool to counteract the widespread losses of seagrass meadows and their associated biodiversity. In the Dutch Wadden Sea, long-term restoration efforts have recently led to the successful restoration of annual eelgrass (Zostera marina) at high densities on a local scale. However, it is yet unknown if restored seagrass plants also lead to improved local biodiversity and ecosystem functioning in the intertidal zone. We therefore compared the macrozoobenthos communities of a small-scale restored meadow to 22 naturally occurring intertidal seagrass meadows. Using a taxonomic and traitbased approach we aimed to study 1) how intertidal seagrasses (Zostera marina and Zostera noltii) affect benthic communities and their functional trait distribution and 2) if a restoredmeadowfacilitates benthic communities similar to natural meadows. We found that both natural and restored seagrasses increased abundances of benthic animals and the richness (both taxonomic and functional) of associated benthic communities compared to nearby unvegetated areas. Additionally, the presence of intertidal seagrass shifted benthic community composition both taxonomically and functionally, thus broadening the niche space for species inhabiting tidal flats. Seagrasses especially facilitated epifaunal species and traits associated with these animals. Surprisingly, our results indicate that the mere presence of seagrass aboveground structure is enough to facilitate benthic communities, as neither higher seagrass cover nor biomass increased benthic biodiversity in the intertidal zone. By studying the effect of seagrass restoration on benthic diversity, we found that the restoredmeadow functioned similarly to the natural meadows after only two years and that the success of our restoration efforts indeed led to local biodiversity enhancements. Our findings contribute to the understanding of the ecological functioning of intertidal seagrasses and can be used to define/refine conservation and restoration goals of these valuable ecosystems. [ABSTRACT FROM AUTHOR]

Decapod crustaceans are important components of the fauna of soft-bottom habitats. In this work, the records of decapod crustaceans are provided through the analysis of a large soft-bottom benthic macroinvertebrates dataset of the Central Mediterranean Sea. Decapod crustacean assemblages were collected in the last twenty years by a Van Veen grab in 42 study sites located along the Italian coasts at depths ranging from 1 up to 120 m. The spatial distribution of the crustaceans examined, which include 120 species belonging to 40 families, was investigated according to the biogeographical zones identified in the Italian seas. The spatial distribution of 36 species was updated, comparing the ISPRA decapod crustacean dataset with the most recent Italian checklists. For the species updated, the number of specimens, the year and season of sampling, and environmental data, such as the bathymetric range and habitat details, are provided for each site investigated. Data are discussed and compared with the existing literature, also referring to what is reported in the World Register of Marine Species (WoRMS), with the aim of contributing to the knowledge of the biodiversity of the marine species and supporting the updating of checklists and registers in the Mediterranean Basin. [ABSTRACT FROM AUTHOR]

Reservoirs are human-made ecosystems with diverse purposes that benefit humans both directly and indirectly. They however cause changes in geomorphological processes such as sediment cycling and influence the composition and structure of aquatic biota. This study aimed to identify water and sediment quality parameters as drivers of macroinvertebrates and fish communities during the cool-dry and hot-wet seasons in the littoral zones of three subtropical reservoirs (Albasini, Thathe and Nandoni). Macroinvertebrates and fish were collected from three sites (n = 3 from each site) in each reservoir. A total of 501 and 359 macroinvertebrates and fish individuals were collected throughout the sampling period, respectively. The present study employed a two-way ANOVA in conjunction with redundancy analysis (RDA) to assess the relationships that exist between water and sediment variables, macroinvertebrates diversity and species abundances across seasons. Based on the two-way ANOVA model, significant differences were observed across reservoirs for evenness, Simpson's diversity, and total abundance, while seasonal differences were observed for most metrics, with exception for evenness. The RDA results identified four water variables (i.e., water temperature, oxidation–reduction potential, pH and conductivity) and one sediment metal (Mg) as the most important parameters in driving the fish community structure. Field observations and metal results attest that the Nandoni reservoir shows high concentrations of metals in sediments as compared to other reservoirs, suggesting that anthropogenic activities such as car washing, brick making, recreation, fishing, wastewater treatment work and landfill site may be the major contributor of metals to the Nandoni reservoir, which accumulate in the littoral zones. Findings of this study highlight the need to analyze reservoir ecological conditions at several scales. The study of macroinvertebrates and fish, water, and sediment chemistry in the littoral zone laid the groundwork for proposing measures for conserving aquatic ecosystems. [ABSTRACT FROM AUTHOR]

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Copyright of Natura Croatica is the property of Natura Croatica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Over recent decades, numerous experiments have consistently demonstrated that species richness significantly influences ecosystem multifunctionality. These variations within ecosystems arise from natural progressions, as well as from human and natural events. Our study focuses on analyzing both the composition and quantitative characteristics of benthic macroinvertebrate populations along the rocky shores of Triport in Vlora, aiming to assess their ecological conditions. Our case study involves three observation sites on the rocky shores of Triport in Vlora, where we examine macroinvertebrates. A key objective of our research was to investigate seasonal variations in population traits across different zones, conducting fieldwork during the spring and summer of 2018 (June and August). We calculated both the total and average densities for each species at each site and during each sampling period. Another critical goal was to evaluate species composition and population quantity traits, comparing these across different seasons and sites, as well as within each site. We also performed statistical analyses to explore changes in species composition and population density and their interrelationships across different seasons and sites. The study identified 67 taxa of benthic macroinvertebrates, predominantly gastropods. Our research highlighted the presence of an intriguing and relatively underexplored group, the Macrozoobenthos, within the study areas. This group's significance is tightly linked to the structure and function of the coastal ecosystem, indicated by the dominance of invertebrate species within the benthic community. Many species within this group serve as indicators of the marine ecosystem's health. In conclusion, the sparse density and unstable nature of the macrozoobenthic community are strong indicators of the poor ecological conditions and environmental stresses affecting the study areas. Factors significantly influencing the characteristics of the macrozoobenthic population include algal cover, the diversity of microhabitats along the shores, and the degree of exposure to wave action. [ABSTRACT FROM AUTHOR]

A statistical analysis of the spatial distribution patterns of the macrozoobenthos in the streams and rivers of European Russia and Latvia (Oka, Don, and Gauja river basins) was carried out. Based on nonmetric multidimensional scaling (NMDS), the distribution of the macrozoobenthos in the study streams was shown to be continuous, with no distinct types of communities distinguished. Based on the ANOSIM method, statistically significant species complexes associated with substrate types, flow velocity, and size of the stream and main river basins were recognized. Using the SIMPER, characteristic and differentiating taxa at the generic or species level for each species complex were delimited, with the life-forms of these taxa evaluated. Although the taxonomic composition of species complexes of flowing waters is weakly predictable, a statistically significant clustering of taxon groups associated with key environmental factors has been found possible. Conducting such research in different hydrological types of water bodies in various geographical regions is a promising direction for the environmental monitoring of freshwater. [ABSTRACT FROM AUTHOR]

The species composition and the structure of the macrophytobenthos, macrozoobenthos, and bottom sediments of Taman Bay are studied. This inlet is inhabited by seagrass Zosteramarina L. which forms vast underwater meadows here. Samples were collected in 2008–2009, before the ongoing rise of salinity in the Sea of Azov. Three main biotopes with different bottom sediment composition (sands, sands with shells, and silts) were identified. They were inhabited by four main macrobenthic biocenoses (unvegetated near-shore biocenosis, mosaic macrophyte vegetation outside the surf zone, pure eelgrass's meadows belt, and the communities, dominated by the mobile macrozoobenthos species with low abundance of macrophytes occupying the central part of the bay). The main environmental factor associated with this distribution of the vegetation was the silt content (grain size <0.001 mm). The spatial structure of the macrozoobenthos correlated with the projective cover of Z. marina. Possible reasons for the revealed pattern in the distribution of communities are discussed. [ABSTRACT FROM AUTHOR]

On 20 June 2020, we sampled eight aquatic habitats from the Iron Gates Natural Park near Cozla to determine the structure of the macrozoobenthic invertebrate assemblages. We measured some of the most important physicochemical parameters of the water in each sampling site (dissolved oxygen, temperature, conductivity, pH). We also determined the number of taxa, number of individuals, Shannon-Wiever index, and evenness in all sample sites. The invertebrate assemblages from the anthropogenic habitats differ compared to the natural habitats. In some of the investigated sites, the values of the water physicochemical parameters were below the tolerance limit of most invertebrate groups, as the assemblages contained a very small number of taxa. The Jaccard and Bray Curtis similarity indexes showed which sites had the most similar communities. The Mann-Whitney test showed significant differences between some of the sites. The correspondence between the environmental factors and the sample sites was highlighted by the CCA analysis. We did not find invasive species in the sample sites, even if they are present in the Danube. The structure of the assemblages and the abundance of the individuals indicate the crucial role of the habitat type in how the species associate to form the macrozoobenthic assemblages. In the same habitat types, local factors (e.g., the producers’ assemblage and the quantity of the debris in the substrate) determine the differences between the communities. [ABSTRACT FROM AUTHOR]

This is the first comprehensive examination of the Turyanchay River in Azerbaijan, focusing on water quality (WQ), contamination, and biodiversity at four different locations: Gabala, Agdash, Udjar and Zardab. The study analysed nutrient (nitrate, ammonium, phosphate) and metal/metalloid (Pb, Cu, Ni, Zn, Mn, Cr, Cd, Fe and Al) contamination levels, as well as the diversity of macrozoobenthos in the river, birds and vegetation. The chemical and biological oxygen demands (COD and BOD), including WQ index (WQI) were also determined for the river. The results showed no significant difference in the levels of nutrients, metal/metalloid, COD, BOD, WQI and macrozoobenthos diversity across different locations (p >.05). However, they revealed temporal fluctuations, with their highest levels being recorded during the warmer months (July and August) and the lowest during the colder months (March and November). The estimated WQI, ranging from 19.6 to 43.6, indicated that the water in the Turyanchay River is safe for household and consumption purposes. Up to 83 species of macrozoobenthos were identified, with Hydropsychidae and Chironomidae showing the highest species richness, followed by Coenagrionidae, Psychomyiidae, Ceratopogonidae, Baetidae, Naididae and Gammaridae. Eighteen bird species, consisting of 11 terrestrial and 7 aquatic birds, were recorded, with eight of these species belonging to the Order Charadriiformes. A total of 42 different plant species belonging to 17 families were identified in the Turyanchay River basin, with Fabaceae being the most widely distributed, followed by Asteraceae and Typhaceae. This study provides important baseline data for the Turyanchay River, offering insights into its freshwater environment and biodiversity, and should support future monitoring efforts. [ABSTRACT FROM AUTHOR]

The species diversity of the entire meta-community is made up of local pools of species of individual communities, including both the totality of actually observed taxonomic groups and species of "dark" diversity, which, by their ecological properties, are theoretically suitable for living in existing conditions and are potentially found during repeated studies. To assess the dark diversity, quantitative indices of suitability of the surveyed areas of the study area are calculated in relation to various taxa of the community under consideration. The study of the species composition of benthic communities was carried out on small and medium lowland rivers, tributaries of the Kuibyshev, Saratov and Volgograd reservoirs, including the rivers of the arid region of the Lake Elton basin. A total of 132 local communities were surveyed, from which 147 taxa of macrozoobenthos were selected for calculations. To highlight the dark diversity, an analysis of the joint occurrence of species was carried out and, using hypergeometric distribution formulas, estimates of the conditional probabilities of the statistical relationship of each of these species with individual sections of the rivers were calculated. Relationships between observed species richness and dark diversity are considered; the occurrence of latent species was tested in sections of rivers of a similar type. The concept of "gray" diversity is introduced, i.e., a subset of observed species, in which the indices of correspondence to the focal area are less than a given threshold. [ABSTRACT FROM AUTHOR]

The aim of this paper is to compare the taxonomic composition and species diversity of the macrozoobenthos in Maritsa River (Bulgaria) and Han River (South Korea). Samples were collected at 15 selected sites in each river, including some of their main tributaries in 2020 and 2021. The number of the taxa recorded in Maritsa River was more than twice as great as in Han River: 192 taxa belonging to 19 systematic groups compared to 88 taxa belonging to 18 groups respectively. The order Ephemeroptera had the highest species richness: 31 taxa in the Bulgarian rivers and 26 taxa in the South Korean ones. The macrozoobenthic communities responded and adapted to the various conditions and impacts in the water environment with changes in the species composition and structure. The analysis of the similarity in the taxonomic composition showed low resemblance between all study sites but displayed distinct separations between the rivers and the two years. In general, the species structure of the macrozoobenthic communities in the studied rivers in Bulgaria was better than that in Han River. In both years, high species diversity was recorded at the reference sites in the rivers, characterized by conditions closely resembling natural environments. The species richness and the evenness of macrozoobenthos were very low at sites downstream subjected to considerable anthropogenic pressure. Some of the communities in Han River were almost destroyed completely. [ABSTRACT FROM AUTHOR]

Macrozoobenthic invertebrate assemblages are a very important component of water ecosystems that reflect water quality. The evaluation of these assemblages in the Jiului Corridor Natura 2000 site can highlight the natural value of aquatic invertebrate biodiversity. Thus, our study aimed to analyze seven streams from the Jiu Corridor Natura 2000 site from the point of view of the macrozoobenthic invertebrate assemblages’ structure. The samples were collected in June 2020. Also, we measured the most important physicochemical parameters of the water. In the sample sites, we found a number of 31 taxa. There were differences between the sites depending on the riverbed type, hydrology, and human impact intensity. Totally, we have identified 15232 individuals of macrozoobenthic invertebrates. Even though the communities in the seven studied watercourses were different, these differences were not statistically significant. This fact, correlated with the high number of individuals and taxa, suggests the relict character of the macrozoobenthic invertebrate communities in the studied small watercourses. These aquatic habitats preserve the region`s biodiversity from before anthropic transformations.

This study aims to determine the composition and structure of the macrozoobenthos community in Batang Air Dingin and water quality based on BMWP ASPT. This study used a survey method in determining the station by purposive sampling, based on typhical environmental condition along the river. Macrozoobenthos samples was collected by using surber net 30x30 cm2. The result showed the community in the form of Gastropods 6 genera, Insecta 26 genera, Oligochaeta 1 genus, and Hirudinea 1 genus. Total density of macrozoobenthos in the Batang Air Dingin river was 1182,22ind/m2 ranging from 180,00 ind/m2 to 402,22 ind/m2 with the highest density was found in the first station and the lowest at station four. The predominant type found at each station is different, station I is Elophyla, Neopherla, Hydropsyche; station II Eukifferiella, Polypedilum, Elophyla, Hydropsyche; station III Clithon, Eukifferiella, Polypedilum, Orthocladius; station IV Clithonand Thiara. The diversity of macrozoobenthos in Batang Air Dingin river range between 1,95-2,51 is classified as moderate with even distribution (E=0,84) range between 0,81-0,89. Batang Air Dingin water quality using BMWP ASPT from upstream to downstream range between 6,12 – 3,5. Classified unpolluted to heavily polluted.

Ecological restoration has become an important management-tool to counteract the widespread losses of seagrass meadows and their associated biodiversity. In the Dutch Wadden Sea, long-term restoration efforts have recently led to the successful restoration of annual eelgrass (Zostera marina) at high densities on a local scale. However, it is yet unknown if restored seagrass plants also lead to improved local biodiversity and ecosystem functioning in the intertidal zone. We therefore compared the macrozoobenthos communities of a small-scale restored meadow to 22 naturally occurring intertidal seagrass meadows. Using a taxonomic and trait-based approach we aimed to study 1) how intertidal seagrasses (Zostera marina and Zostera noltii) affect benthic communities and their functional trait distribution and 2) if a restored meadow facilitates benthic communities similar to natural meadows. We found that both natural and restored seagrasses increased abundances of benthic animals and the richness (both taxonomic and functional) of associated benthic communities compared to nearby unvegetated areas. Additionally, the presence of intertidal seagrass shifted benthic community composition both taxonomically and functionally, thus broadening the niche space for species inhabiting tidal flats. Seagrasses especially facilitated epifaunal species and traits associated with these animals. Surprisingly, our results indicate that the mere presence of seagrass aboveground structure is enough to facilitate benthic communities, as neither higher seagrass cover nor biomass increased benthic biodiversity in the intertidal zone. By studying the effect of seagrass restoration on benthic diversity, we found that the restored meadow functioned similarly to the natural meadows after only two years and that the success of our restoration efforts indeed led to local biodiversity enhancements. Our findings contribute to the understanding of the ecological functioning of intertidal seagrasses and can be used to define/refine conservation and restoration goals of these valuable ecosystems.

Tidal flats are among the ecologically richest areas of the world where sediment composition (e.g. median grain size and silt content) and the macrozoobenthic presence play an important role in the health of the ecosystem. Regular monitoring of environmental and ecological variables is essential for sustainable management of the area. While monitoring based on field sampling is very time-consuming, the predictive performance of these variables using satellite images is low due to the spectral homogeneity over these regions. We tested a novel approach that uses features from a variational autoencoder (VAE) model to enhance the predictive performance of remote sensing images for environmental and ecological variables of tidal flats. The model was trained using the Sentinel-2 spectral bands to reproduce the input images, and during this process, the VAE model represents important information on the tidal flats within its layer structure. The information in the layers of the trained model was extracted to form features with identical spatial coverage to the spectral bands. The features and the spectral bands together form the input to random forest models to predict field observations of the sediment characteristics such as median grain size and silt content, as well as the macrozoobenthic biomass and species richness. The maximum prediction accuracy of feature-based maps was close to 62% for the sediment characteristics and 37% for benthic fauna indices. The encoded features improved the prediction accuracy of the random forest regressor model by 15% points on average in comparison to using just the spectral bands. Our method enhances the predictive performance of remote sensing, in particular the spatiotemporal dynamics in median grain size and silt content of the sediment thereby contributing to better-informed management of coastal ecosystems.

The aim of this paper is to share more information about cumacean crustaceans, specifically their presence, biogeographical distribution, and preferred sediment type in the Italian Seas. Samples were collected on the soft bottom at different sites, ranging from 3 to 158 m in depth, from 2001 to 2021. The specimens collected represented a total of 29 species belonging to 5 families (Bodotriidae, Leuconidae, Nannastacidae, Diastylidae, and Pseudocumatidae). The results were compared with the most recent Italian fauna checklists and the available scientific literature on this group. [ABSTRACT FROM AUTHOR]

The Mekong River is the 10th largest river in the world. It is recognised as the most productive river in Southeast Asia and economically essential to the region, with an estimated 60-65 million people living in the lower Mekong Basin. The Mekong Delta within Vietnam is considered a highly vulnerable ecosystem under threat from increasing anthropogenic pressure, such as dam construction and, as a consequence, the Delta is sinking and altering the natural hydrological cycle. Dams also lead to eutrophication and pollution of downstream water from regulated water flux and water stagnation. Another threat is climate change coupled with the lower rainfall, which could lead to an increased risk of drought in the Mekong Delta Basin. Thus, these project data represent an important baseline reference. The ecological health of the Mekong Delta's environment, as indicated by the quality and availability of its water and biological resources, largely determines the economic and social development of the region, which produces about half of the agriculture and aquaculture products of Vietnam. New information This paper reports quantitative data on the biodiversity of six groups of aquatic organisms: bottom and pelagic fish, macrozoobenthos, microorganisms, phyto- and zooplankton in the Mekong Delta within Vietnam, as well as data on the physicochemical parameters of water and bottom sediments. The data were collected during 2018-2022 as part of the Ecolan E-3.4 programme within the framework of the research plan of the Joint Russian-Vietnamese Tropical Research and Technological Center. All presented datasets are published for the first time. [ABSTRACT FROM AUTHOR]

The growth and production of glacial relic amphipods Monoporeia affinis in a small subarctic lake were studied based on detailed seasonal observations in 2019–2021. Growth and production were closely related to trophic conditions (chlorophyll a concentration). The maximum values were observed at low water temperatures (~5°C) in early summer, coinciding with the spring maximum of chlorophyll. The summer warming of bottom waters was accompanied by a decrease in the growth rate of amphipods, which is apparently associated with the consumption of most of the primary production in the pelagic zone. It is concluded that current climatic conditions can adversely affect glacial relicts even in cold-water lakes of the subarctic zone. [ABSTRACT FROM AUTHOR]

We present data on the taxonomic diversity and structure of macroinvertebrate communities in small, mostly 1st and 2nd order permanent streams from Struma, Mesta and Vardar watersheds (7th Ecoregion "Eastern Balkans") and analyse similarity in communities between/within studied basins. We reveal the characteristic elements of the macrozoobenthos from representative sites of R3- (mountainous) and R5- (semi-mountainous) river types. In total 69 samples from 38 sites were collected in autumn 2017 and spring 2018. The variation of the number of taxa, total abundance, relative abundance, species diversity and richness, evenness and index of dominance were analysed. A total of 280 taxa were recorded, and insects dominated the macroinvertebrate communities (> 70%). Overall, site similarities reflected the key macroinvertebrate metacommunities in R3- and R5-river type sections that provided higher β-diversity and lower similarities compared to the remainder of the watersheds. MDS- and dbRDA analyses separated the river basins by stream size and substratum heterogeneity. The highest α- and β-diversity were recorded within the Struma River watershed, which contributed to the higher γ-diversity and reflected the typical macroinvertebrate assemblages from the studied rivers of this Ecoregion. These results are important in application of management protocols especially when alike activities involve such river ecosystems. [ABSTRACT FROM AUTHOR]

Lake Semayang is a floodplain lake with an area of ±13,000 ha. Over time, this lake has experienced a lot of ecological pressure due to anthropogenic changes that have an impact on the condition of the waters in it. Water quality is highly dependent on the presence of aquatic biota. One of the aquatic biotas that are very important in determining the condition of the waters is the benthos, namely animals that live on the bottom of the waters and are bioindicators from a biological point of view. The methodology is by taking benthic samples in the field using the Ekman Grab, identifying, and analyzing the calculation of abundance, diversity, and looking at the condition of the surrounding waters. This paper describes the presence of benthic macroinvertebrate communities as bioindicators of aquatic health. The research was conducted from March to October 2018 at five observation stations with purposive sampling. The results showed that the highest macrozoobenthos communities were in the families Tubificidae and Thiaridae, namely Branchiura sowerbyi and Melanoides sp. The presence of B. sowerbyi and Melanoides sp indicates that the condition of the waters is still in the good category with moderate diversity values, rich in organic matter with low dissolved oxygen (DO) conditions, and high suspended particles. [ABSTRACT FROM AUTHOR]

This paper presents the state of biota of Drenova Reservoir in Bosnia and Herzegovina (B&H) as water quality indicator. The Drenova reservoir has a multiple role: protection of the Vijaka river basin from floods, provision of water for the Prnjavor fishpond, as well as sport fishing. Bearing in mind the multifunctionality of this reservoir, but also the scarcity of data on the biota of this water body, in 2017, research on phytoplankton, zooplankton, macrozoobenthos and ichthyofauna was performed. Based on the obtained results (qualitative and quantitative composition, saprobic index according to Pantle–Buck, Shannon index), it was established that the water of Drenova Reservoir, as far as phytoplankton and zooplankton community is concerned, corresponds to the transition from oligosaprobic to β-mesosaprobic waters while macrozoobenthos and ichthyofauna refer to β-mesosaprobic water. A small number of representatives of phytoplankton (both qualitatively and quantitatively) is noticeable, as well as the absence of species common to this type of aquatic ecosystems in the observed period. The state of macrozoobenthos taxa is expected considering the properties of the substrate of this accumulation. Ichthyocenosis is characterized by a small number of species, but also by a small number of individuals within those species. [ABSTRACT FROM AUTHOR]

Simple Summary: The warming of Arctic regions has led to an increase in extended ice-free periods in the continental shelf of the northeastern Barents Sea. A study on the Makarov Strait in the southwestern part of the St. Anna Trough in autumn 2019 investigated the effect of this process on the structure and functioning of benthic communities. It was found that the biodiversity and structure of local macrozoobenthos were connected with the duration of ice-free periods because this variable influenced vertical carbon flux and was found to be the primary predictor for faunal abundance and diversity indices. Two faunal groups were identified, corresponding to short and long open-water periods. Our results may have important implications for the conservation and monitoring of this region. The continental shelf of the northeastern Barents Sea is presently experiencing a weak influx of Atlantic water from the west. In recent times, warming in Arctic regions has led to an increase in extended ice-free periods in this area, instead of significantly elevating water temperatures. The implications of this phenomenon on the structure and functioning of benthic communities were investigated during the autumn of 2019 within the Makarov Strait, located in the southwestern part of the St. Anna Trough. The macrozoobenthic communities exhibited a clear connection with the duration of ice-free periods. This variable influenced a vertical carbon flux, which subsequently served as the primary predictor for faunal abundance and diversity, as demonstrated by redundancy and correlation analyses. Two faunal groups were identified, corresponding to short and long open-water periods. Both groups had similar alpha diversity (65 ± 6 and 61 ± 9 species per station) and biomasses (39 ± 13 and 47 ± 13 g m−2) but displayed differing abundances (1140 ± 100 vs. 4070 ± 790 ind. m−2) and other diversity indices. We observed a decline in the proportion of polychaetes, accompanied by an increase in the proportion and diversity of bivalves, as well as a rise in the abundance of infaunal species, sub-surface deposit feeders, and mobile suspension feeders, in response to the increasing vertical carbon flux. The potential increase in anthropogenic pressures related to oil development in the northeastern Barents Sea highlights the importance of our study for conservation and monitoring efforts in the region. [ABSTRACT FROM AUTHOR]