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The collection of macrozoobenthos from the Gostelja River was conducted in May 2022. Sampling was carried out at 7 locations. Through qualitative-quantitative analysis of macrozoobenthos, a total of 19 taxa or 355 individuals belonging to different taxonomic groups such as Mollusca, Turbellaria, Ephemeroptera, Plecoptera, Trichoptera, Diptera, and Odonata were recorded. Based on the conducted research and index calculations, we can conclude that different water quality classes can be observed along the course of the Gostelja River.

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.

There is ample evidence that tube-dwelling invertebrates such as chironomids significantly alter multiple important ecosystem functions, particularly in shallow lakes. Chironomids pump large water volumes, and associated suspended and dissolved substances, through the sediment and thereby compete with pelagic filter feeders for particulate organic matter. This can exert a high grazing pressure on phytoplankton, microorganisms, and perhaps small zooplankton and thus strengthen benthic-pelagic coupling. Furthermore, intermittent pumping by tube-dwelling invertebrates oxygenates sediments and creates a dynamic, three-dimensional mosaic of redox conditions. This shapes microbial community composition and spatial distribution, and alters microbe-mediated biogeochemical functions, which often depend on redox potential. As a result, extended hotspots of element cycling occur at the oxic-anoxic interfaces, controlling the fate of organic matter and nutrients as well as fluxes of nutrients between sediments and water. Surprisingly, the mechanisms and magnitude of interactions mediated by these organisms are still poorly understood. To provide a synthesis of the importance of tube-dwelling invertebrates, we review existing research and integrate previously disregarded functional traits into an ecosystem model. Based on existing research and our models, we conclude that tube-dwelling invertebrates play a central role in controlling water column nutrient pools, and hence water quality and trophic state. Furthermore, these tiny ecosystem engineers can influence the thresholds that determine shifts between alternate clear and turbid states of shallow lakes. The large effects stand in contrast to the conventional limnological paradigm emphasizing predominantly pelagic food webs. Given the vast number of shallow lakes worldwide, benthic invertebrates are likely to be relevant drivers of biogeochemical processes at regional and global scales, thereby mediating feedback mechanisms linked to climate change.

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.

Macrozoobenthos live sedentary at the bottom of the waters with slow movements and a relatively long-life cycle, and they are able to respond continuously to changes in water conditions. The aim of this study is to analyze macrozoobenthic ecology as an indicator of water quality at Margagiri-Grenyang coastal waters, Banten Bay. The study was carried out for 5 months from July-November 2022 with six stations. Macrozoobenthos samples were taken using Petersen Grab, and water quality was measured in situ and ex situ. Data analysis was conducted to estimate abundance, biological indices, PCA, similarity index, and AMBI and M-AMBI. The macrozoobenthos at the study site were composed of six phyla (Molusca, Annelida, Echinodermata, Arthropoda, Hoplonemertea, and Nemertea). The highest density of the marozoobenthos was found in July (3178 ind/m 2 ), with moderate diversity (H′) (2.535–2.758), medium-high evenness (E) (0.742–0.833), and low dominance (C) indices (0.157–0.241). Based on PCA, the distribution of macrozoobenthos is influenced by turbidity and TSS parameters. AMBI and M-AMBI analysis showed that macrozoobenthos undisturbed and indicated by good-high water quality.

Macrozoobenthos, as benthic organisms, have an important role in the ecosystem and can be used as bioindicators of aquatic environmental quality. This study aims to analyze the community structure of macrozoobenthos in the waters of Pantai Indah Kapuk (PIK) and its relationship with environmental parameters. Samples were taken for 6 months (August 2024 to January 2025) at four stations using Van Veen Grab, while the parameters were analyzed in the laboratory to identify species, density, diversity index, evenness index, dominance index, PCA, and distribution map. The results showed that there were seven classes and 30 genera of macrozoobenthos consists seven classes (Bivalvia, Cirripedia, Gastropoda, Hydrozoa, Malacostraca, Nemertea, and Polychaeta). The most common genus found was Perna sp. from the class of Bivalvia. The highest density was found at Station 1 (112.37 ind/m2) and the lowest one at Station 3 (14.21 ind/m2). The diversity index was in the medium category, with the highest value at Station 2 (1.13). Station 3 had the highest dominance index (0.23), indicating the dominance of a certain genus due to environmental pressure. This study shows that macrozoobenthos communities in PIK are influenced by environmental conditions, with the greatest pressure occurring at Station 3, which is near the reclamation area.

1. Most of the world's rivers are affected by dams and weirs. Information on the quantitative and qualitative effects of weirs across biological communities is crucial for successful management and restoration of stream ecosystems. Yet, there is a lack of comprehensive studies that have analysed the serial discontinuity in direct proximity of weirs including diverse taxonomic groups from algae to fish. 2. This study compared the abiotic stream habitat characteristics upstream and downstream of weirs as well as their effects on the community structure of periphyton, aquatic macrophytes, macroinvertebrates and fish at five different study rivers. 3. Physicochemical habitat characteristics discriminated strongly between upstream and downstream sides of weirs in terms of water depth, current speed, substratum composition and the transition between free-flowing water and interstitial zone. Accordingly, abundance, diversity, community structure and functional ecological traits of all major taxonomic groups were indicative of serial discontinuity, but the discriminative power of individual taxonomic groups strongly differed between rivers. 4. The simultaneous inclusion of abiotic habitat variables, taxonomic diversity and biological traits in multivariate non-metric multidimensional scaling was most comprehensive and powerful for the quantification of weir effects. In some cases, the intrastream discrimination induced by weirs exceeded the variation between geographically distant rivers of different geological origin and drainage systems. Community effects were generally detectable on high levels of taxonomic resolution such as family or order level. 5. Synthesis and applications. River sections in spatial proximity to weirs are affected seriously and should be included in the ecological assessments of the European Water Framework Directive. Multivariate models that include several taxonomic groups and physicochemical habitat variables provide a universally applicable tool for the ecological assessment of impacts on serial discontinuity and other Stressors on stream ecosystem health.

Ongoing climate change is causing rapid changes in biodiversity and has ecological impacts on coastal marine systems. Predicting scenarios of how these pressures will affect bioturbation, a process vital to marine communities and human well-being, has become an important task. A first step is a better understanding of the interaction between macrofauna and the surrounding environment. Here, bioturbation (local and non-local sediment mixing) was surveyed using a high-resolution depth distribution of macrobenthos in the southwestern Baltic Sea, which is characterized by different sediment types and faunal communities. The distribution of local and non-local mixing with increasing non-local transports from west to east was explained by comparing vertical chlorophyll profiles and organisms’ depth distributions. The main bioturbators were identified based on chlorophyll profiles and community bioturbation potential (BPc) and by categorizing the main species into functional groups. Diastylis rathkei is most important for local sediment mixing, and bivalves, e.g. Arctica islandica and Limecola balthica, together with polychaetes, e.g. Nephtys hombergii and Scoloplos armiger, are most important for non-local transports. Significant correlations between modeled local and non-local mixing intensities and calculated BPc (105−1298 m−2) indicate that BPc is a suitable bioturbation indicator; however, it does not provide information on the different modes of mixing. Some species categorized as bio diffusors in the literature were found to cause non-local mixing according to their feeding behavior (e.g. L. balthica), size (e.g. Abra alba) or biomass (e.g. A. islandica).

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.

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.