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Salting of roadways contaminates local waterways via snowmelt and precipitation runoff, eliciting various toxicological impacts on aquatic ecosystems. Recently, "eco‐friendly" deicing alternatives have been introduced in hopes of mitigating environmental impacts of deicing agents, while maintaining human safety. These "eco‐friendly" alternatives may pose their own set of environmental concerns that require further study. While the potential toxicity of road salts has been evaluated for various aquatic species, the environmental factors that may influence this toxicity are less understood; and for emerging deicing alternatives, there is a lack of literature documenting these potential implications. For aquatic organisms, the highest exposure to road salts may coincide with reduced food availability, namely during the winter months. The present study evaluates the effect of a conditioning diet on the sensitivity of adult Hyalella azteca to an "eco‐friendly"‐labeled beet deicer (Snow Joe MELT Beet‐IT). Various conditioning diets were examined, including TetraMinTM, TetraMin and diatom (Thalassiosira weissflogii) combinations, and TetraMin and conditioned Acer sacharum leaves. For each diet type, 48‐ and 96‐h water‐only toxicity bioassays were conducted with adult H. azteca. These results were compared to organisms which experienced a 96‐h starvation period prior to exposure and culture organisms. Diet types representing excess quality and quantity of food significantly decreased the toxicity of beet deicer to the organisms. However, starvation likely increases the toxicity of road salts to H. azteca. Therefore, the quantity and quality of food available to H. azteca may influence their sensitivity to deicing agents. Environ Toxicol Chem 2024;43:2608–2615. © 2024 SETAC [ABSTRACT FROM AUTHOR]

Context: In efforts to mitigate anthropogenic impacts on floodplain biodiversity, restoration measures that enhance habitat connectivity have been applied. However, these approaches have either neglected the spatial position of water bodies or the dynamic nature of the floodplain ecosystem. Objectives: This study focuses on the novel application of the multilayer network framework to assess changes in the aquatic habitat connectivity in floodplains, showcasing its application in the context of aquatic passive dispersal (drift) of two indicator groups of benthic macroinvertebrates (Oligochaetes and Chironomids) Methods: Our case study is located in the Donau-Auen National Park in Austria and follows floodplain restoration measures (side-channel reconnection) applied in the mid-1990s. Multilayer networks were constructed to represent the conditions before, short-term, and long-term after restoration to quantify habitat connectivity across inundation frequencies. Our network analyses involved multilayer correlation, static and dynamic monolayer centralities (centrality profiles), and multilayer centrality assessments. We used a Partial Least Squares Regression analysis as a variable selection tool to identify which centrality measures better explained the variance in α diversity and Local Contributions to Beta Diversity (LCBD) of benthic macroinvertebrates. Results: In the short-term, our connectivity analysis indicated an increase in habitat connectivity. However, centrality profiles, multilayer correlation, and multilayer centrality techniques identified a long-term decrease in connectivity. Multilayer centralities had higher Variable Importance in the Projection scores (VIP) than their monolayer counterpart in explaining variations in α diversity and LCBD for strict aquatic dispersers. Meanwhile, for flying dispersers, monolayer centralities had the highest VIP scores for explaining α diversity. Conclusions: This study underscores the relevance of integrating dynamic aspects of water-mediated transport beyond traditional pairwise distances. Although in this study we apply this tool by showcasing the aquatic passive dispersal mode, the application of this method can be extended to other dispersal modes and representative abilities for diverse groups of aquatic organisms. The expanding cross-disciplinary applications and open-source tool development for multilayer networks offer practical implications for planning and evaluating management measures. [ABSTRACT FROM AUTHOR]

Abstract Transitional waters are important habitats both for biodiversity and ecological functions, providing valuable natural resources and relevant ecosystem services. However, they are highly susceptible to climate changes and anthropogenic pressures responsible for biodiversity losses and require specific biomonitoring programs. Benthic macroinvertebrates are suitable as ecological indicators of transitional waters, being affected by biological, chemical, and physical conditions of the ecosystems about their life cycles and space-use behaviour. The advent of high-throughput sequencing technologies has allowed biodiversity investigations, at the molecular level, in multiple ecosystems and for different ecological guilds. Benthic macroinvertebrate communities’ composition has been investigated, at the molecular level, mainly through DNA extracted from sediments in marine and riverine ecosystems. In this work, benthic macroinvertebrate communities are explored through eDNA metabarcoding from water samples in a Mediterranean transitional water ecosystem. This research highlighted the validity of eDNA metabarcoding as an efficient tool for the assessment of benthic macroinvertebrate community structure in transitional waters, unveiling the spatial heterogeneity of benthic macroinvertebrate communities correlated to the measured environmental gradients. The results suggest that peculiar features of transitional water ecosystems, such as shallow waters and limited currents, facilitate the assessment of benthic macroinvertebrate communities through environmental DNA analysis from surface water samples, opening for more rapid and accurate monitoring programs for these valuable ecosystems.

Transitional waters are important habitats both for biodiversity and ecological functions, providing valuable natural resources and relevant ecosystem services. However, they are highly susceptible to climate changes and anthropogenic pressures responsible for biodiversity losses and require specific biomonitoring programs. Benthic macroinvertebrates are suitable as ecological indicators of transitional waters, being affected by biological, chemical, and physical conditions of the ecosystems about their life cycles and space-use behaviour. The advent of high-throughput sequencing technologies has allowed biodiversity investigations, at the molecular level, in multiple ecosystems and for different ecological guilds. Benthic macroinvertebrate communities' composition has been investigated, at the molecular level, mainly through DNA extracted from sediments in marine and riverine ecosystems. In this work, benthic macroinvertebrate communities are explored through eDNA metabarcoding from water samples in a Mediterranean transitional water ecosystem. This research highlighted the validity of eDNA metabarcoding as an efficient tool for the assessment of benthic macroinvertebrate community structure in transitional waters, unveiling the spatial heterogeneity of benthic macroinvertebrate communities correlated to the measured environmental gradients. The results suggest that peculiar features of transitional water ecosystems, such as shallow waters and limited currents, facilitate the assessment of benthic macroinvertebrate communities through environmental DNA analysis from surface water samples, opening for more rapid and accurate monitoring programs for these valuable ecosystems. [ABSTRACT FROM AUTHOR]

In recent years, the sediment compartment has gained more attention when performing toxicity tests, with a growing emphasis on gaining more ecological relevance in testing. Though many standard guidelines recommend using artificially formulated sediment, most sediment studies are using natural sediment collected in the field. Although the use of natural field‐collected sediment contributes to more environmentally realistic exposure scenarios and higher well‐being for sediment‐dwelling organisms, it lowers comparability and reproducibility among studies as a result of, for example, differences in the base sediment depending on sampling site, background contamination, particle size distribution, or organic matter content. The aim of this methodology contribution is to present and discuss best practices related to collecting, handling, describing, and applying natural field‐collected sediment in ecotoxicological testing. We propose six recommendations: (1) natural sediment should be collected at a well‐studied site, historically and by laboratory analysis; (2) larger quantities of sediment should be collected and stored prior to initiation of an experiment to ensure a uniform sediment base; (3) any sediment used in ecotoxicological testing should be characterized, at the very least, for its water content, organic matter content, pH, and particle size distribution; (4) select spiking method, equilibration time, and experimental setup based on the properties of the contaminant and the research question; (5) include control‐, treated similarly to the spiked sediment, and solvent control sediment when appropriate; and (6) quantify experimental exposure concentrations in the overlying water, porewater (if applicable), and bulk sediment at least at the beginning and the end of each experiment. Environ Toxicol Chem 2024;43:1757–1766. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

Urban sprawl leads to the degradation of aquatic environments and, consequently, to the destruction of biodiversity. With the aim of highlighting the distribution profile of benthic macroinvertebrates in the city of Yaoundé and its surroundings according to the level of degradation, this study was carried out in seven rivers. A total of 144 taxa of benthic macroinvertebrates, belonging to 74 families, 15 orders, five classes, and three phyla, were collected from seven rivers in urban, peri-urban, and forest environments on Yaoundé and its surroundings. The self-organizing map (SOM) analysis tool was used to group the collected taxa from all stations into three clusters or affinity cores. The indicator value analysis (IndVal) method was employed to determine, based on their ecological preferences, which organisms were most likely to belong to each group. Out of the 144 collected taxa, only 44 were indicated to represent the three different groups. Thus, three communities were defined: the Hydropsyche community, with Hydropsyche sp. as the predominant taxon in Group III, characterizing well-oxygenated and low-mineralized stations; the Hydrocyrius community, where the species Hydrocyrius sp. predominates in Group I, describing stations with low oxygenation and moderate mineralization; and the Lumbriculidae community, where Lumbriculidae is the taxon associated with environments with high mineralization and critical oxygenation. These two methods contribute to the biomonitoring of tropical aquatic environments, firstly by grouping organisms by affinity and then identifying those that reflect the environment conditions. This facilitates the detection of changes in the quality of hydrosystems and guides management and conservation efforts. [ABSTRACT FROM AUTHOR]

Ongoing climate change threatens the biodiversity of glacier‐fed river ecosystems worldwide through shifts in water availability and timing, temperature, chemistry, and channel stability. However, tropical glacier‐fed rivers have received little attention compared to those in temperate and Arctic biomes, despite their unique biodiversity potentially responding differently due to additional stress from higher altitude locations thus lower oxygen availability, diurnal freeze–thaw cycles, and annual monsoon rainfall disturbances. This study quantified aquatic biodiversity responses to decreasing glacier cover in the Cordillera Blanca range of the Peruvian Andes. Ten rivers were studied along a gradient of decreasing glacier cover in the Parón, Huaytapallana, and Llanganuco basins, with a specific focus on macroinvertebrates and physicochemical parameters in both the dry and wet seasons. We found higher temperatures, more stable and lower turbidity rivers as glacier cover decreased, which were related significantly to higher local diversity and lower β‐diversity. Analysis of similarity revealed significant differences in the macroinvertebrate community among rivers with high, medium, or low glacier cover, illustrating turnover from specialists to generalists as glacial influence decreased. Redundancy analysis demonstrated that there were more species found to prefer stable beds and water temperatures in medium and low glacier cover in a catchment rivers. However, certain taxa in groups such as Paraheptagyia, Orthocladiinae, Anomalocosmoecus, and Limonia may be adapted to high glacial influence habitats and at risk of glacier retreat. Although species composition was different to other biomes, the Cordillera Blanca rivers showed similar benthic macroinvertebrate biodiversity responses to glacier retreat, supporting the hypothesis that climate change will have predictable effects on aquatic biodiversity in mountain ranges worldwide. [ABSTRACT FROM AUTHOR]

Natural Flood Management (NFM) aims to reduce flood hazard by working with nature and is gaining prominence worldwide. One particular NFM technique involves the use of channel‐spanning woody dams that maintain a clearance height above baseflow. These dams function by increasing channel roughness during high flows and by forcing excessive water onto the floodplain. Whether these dams provide additional benefits to nature remains unclear. While there are many existing studies on natural in‐stream wood structures, very few have documented the impact of NFM woody dams in particular. This study adopted a multidisciplinary approach and a Before–After Control–Impact (BACI) research design to assess whether NFM woody dams installed in a small upland catchment had driven changes in benthic macroinvertebrate assemblages and benthic metabolic activities through the geomorphic changes that they had created. Statistical results indicate that macroinvertebrate density, richness, and diversity did not show any difference between stream reaches with and without NFM woody dams. The metrics were generally not related to grain‐size parameters and volumes of sediments eroded or deposited. However, individual genera such as Baetis and Rhithrogena became more dominant in the control reach towards the end of the study period, likely due to the higher flow velocities and coarser sediments there resulting from the lack of flow resistance in the absence of NFM woody dams. Rates of benthic respiration (but not rates of photosynthesis) were consistently significantly higher in woody dam reaches than in control reaches, likely due to the presence of patches of finer sediments in the former. [ABSTRACT FROM AUTHOR]

Impacts of metal pollution, either on water or in sediments within aquatic systems have been a serious challenge globally. Little is known about the ecological impacts of metal pollution on benthic macroinvertebrates species in sub–tropical river systems. The aim of this study was to examine benthic macroinvertebrates community composition in relation to sediment metal concentrations and other physicochemical variables in the Mutshundudi River system. Benthic macroinvertebrates sampling and community composition analysis, sediment collection, processing, metal analysis and assessment of water variables in the river system were done across two seasons at 12 sampling sites. The river was categorized into three segments: upstream, midstream and downstream. The results from geo‐accumulation (Igeo) values showed that sediments were loaded with Na, Zn, and B in all river segments. In comparison with South African water quality guidelines for aquatic ecosystems, water quality ranged from good at upstream sites because of low anthropogenic activities to very poor in downstream sites because of high anthropogenic activities. Sediments from the Mutshundudi River showed significant differences on high concentrations of metals (i.e., Mg, K, Na, and Cu) and seasonal variations. Both water quality and sediment chemistry were considered the driving factors of benthic macroinvertebrates, since species densities and composition reduced with a decline in water and sediment quality during both cool–dry and hot–wet seasons. Continuous build‐up of the metal contaminants, such as Mg, K, Na, and Cu in river sediments may pose adverse impacts on macroinvertebrate community structure. [ABSTRACT FROM AUTHOR]

Human encroachment, urban and agricultural expansion, frequent droughts, eutrophication, infestation of weeds, and overexploitation of resources has predominantly impacted the water quality and biodiversity of the Baraila wetland. The present seasonal study has aimed to explore an under-researched subject of analyzing the water quality of the wetland through multi-metric biomonitoring approaches in 2022. A total of 24 water and benthic samples were collected from the four sampling locations. All the water parameters were within a suitable range to support a diverse range of flora and fauna, except total suspended solids (TSS) and nutrients, indicating toward the impact of agricultural expansion in the wetland's area. Of the 13 identified families of benthic macroinvertebrates, the semi-tolerant families of Viviparidae and Bithyniidae have dominated the wetland, with a relative abundance of 27.04 and 37.77%, respectively, in the comparative seasons. Moreover, the indices used in the study have categorized the wetland under moderately polluted condition. The Hierarchical Cluster Analysis (HCA) has revealed the sensitivity toward organic pollution and habitat preferences has played a major role in the species-specific assemblage of benthic community. The Mantel's correlogram further validates that the moderately polluted status of wetland has favored semi-tolerant to tolerant fauna in the wetland. HIGHLIGHTS The study uses biomonitoring to document the water quality of Baraila Wetland.; It was marked by the dominance of semi-tolerant to tolerant benthic species.; The TSS and nutrients mainly degrade the water quality of the wetland.; The diversity and biotic indices classified the wetland as moderately polluted.; The HCA and Mantel's correlogram have explained the assemblage of benthic fauna.;

As bioindicators, benthic macroinvertebrates are often used to assess stream quality. Based on standard hydrobiological study techniques, the physicochemical and biological health status of the Missolé stream was assessed. Waters of the Missolé stream were found to be slightly acidic (pH: 6.23–6.26) and well-oxygenated (O2: 69.80–76.80%), with low values of temperature (T°: 23.60–24° C), turbidity (49.40–88.40 FTU) and mineralized ions (NH4+: 0–1.19 mg/L; NO2-: 0–1.61 mg/L; NO3-: 0.02–6.80 mg/L). Concerning aquatic invertebrate communities, a total of 489 individuals, grouped in two classes, eight orders and 35 families, all belonging to the phylum Arthropoda, were collected and identified. The class of Insecta was the most diversified, with seven orders and 32 families, while that of Crustacea had only one order and three families. Overall, Insecta accounted for 52.35% of the total abundance, and Decapod Crustacea was 47.65%. The three predominant families were Palaemonidae, Dytiscidae and Atyidae. Shannon and Weaver (H’) and Piélou’s evenness (J) indices were high at all stations and showed a slight decrease from upstream to downstream. In the same vein, the Hilsenhoff Biotic Index (HBI) classified the water quality of the Missolé stream as medium. Overall, this suburban aquatic ecosystem offers moderately favorable living conditions for aquatic biota.

Slimy sculpin (Uranidea cognata) inhabit coldwater streams in southeastern Minnesota, USA, many of which were subjected to probable 2000-year flood events in August 2007. Floods scoured streambeds, created new stream channels, and greatly reduced benthic invertebrate communities that serve as the primary food resource for sculpin. Diets and Fulton condition of sculpin in Gilmore Creek (with moderate flooding) and Garvin Brook (with very severe flooding) had been examined just prior to flooding and were re-examined 2 weeks after flooding to assess possible diet and condition changes. Diets, body condition, and reproductive fitness of sculpin were examined 7 months post-flood in these same two streams, plus nearby Trout Run (which also experienced very severe flooding). Sculpin condition declined slightly post-flood in Garvin Brook but improved in Gilmore Creek. Prior to spring spawning, the condition of Garvin Brook sculpin had improved, but Gilmore Creek fish condition had worsened. Sculpin diets were more diverse before and after flooding in Gilmore Creek than in Garvin Brook, although the diets of fish from both streams were dominated (>55%) by midge (Diptera: Chironomidae) larvae. Diets remained largely unchanged before versus after flooding in the more severely flooded Garvin Brook, but they changed in Gilmore Creek, becoming more midge-dominated. Prey number per sculpin stomach declined post-flood in Gilmore Creek but not in Garvin Brook, although the dry mass of prey/fish wet mass declined post-flood in both streams. Pre-spawn sculpin displayed no patterns in reproductive fitness (gonadosomatic index, hepatosomatic index, oocyte number) among the three streams that may have been related to flooding severity the previous summer. Sculpin diets and condition were not altered as expected by flooding, and food resource recovery apparently was rapid enough to prevent longer-term impacts on sculpin condition and reproductive fitness in the streams examined. [ABSTRACT FROM AUTHOR]

This study was carried out to determine water quality of the Kum Stream and to compare the performance of the Saprobe Index (SI), several modifications of Biological Monitoring Working Party (BMWP), several modifications of Average Score Per Taxon (ASPT), Belgian Biotic Index (BBI), Family Biotic Index (FBI), EPT-Taxa [%], Simpson's (SDI), Shannon-Wiener (SWDI) and Margalef (MDI) diversity indices. Six sampling stations were determined and the samplings were carried out seasonally. Biotic and diversity indices based on benthic macroinvertebrates have been applied using Asterics software. Pearson's based correlations were applied to the indices in order to determine the proper biotic indices. A total of 37 taxa which belong to Gastropoda, Oligochaeta, Crustacea and Insecta were detected. The dominant group of the benthic macroinvertebrates was Insecta with 26 taxa. According to the result of ANOSIM (Analysis of Similarity); no statistically significant difference was found between the seasonal distributions of the species (p = 0.267; R: 0.038). According to the MANOVA (Multivariate Analysis of Variance) result, the seasons didn't show a significant difference on the linear combination with environmental variables (p = 0.138 > 0.05). According to the results of CCA (Canonical Correlation Analysis), it was determined that the groups known for their sensitivity to pollution showed a positive correlation with the DO and pH variables, while the groups with high tolerance levels and containing many species as pollution indicators showed a positive correlation with the temperature, TU and EC variables. As a result of this research, the water quality of the Kum Stream was determined as polluted. BBI, ASPT and BMWP indices were more proper than SI and FBI indices to determine the water quality of the Kum Stream. [ABSTRACT FROM AUTHOR]

First-order streams serve as a nursery of macroinvertebrates which act as secondary producers in the aquatic food chain and indicators of water quality. The present investigation conducted on three first-order streams of Badiyar Gad revealed Trichoptera to be the most diverse order followed by Ephemeroptera, Diptera, Coleoptera, Odonata, Lepidoptera, Plecoptera, Hemiptera, Arhynchobdellida, and Decapoda, indicating good water quality for these streams. High density, diversity, and even distribution of benthic macroinvertebrates during the winter season indicated stable ecosystems and healthy water quality. The presence of 35 families and 52 genera indicates a good habitat with numerous ecological niches for the macroinvertebrates. Two genera Maruina and Neophylax were identified as unique in these streams. They have not been previously reported from the Garhwal Himalayan streams. [ABSTRACT FROM AUTHOR]

As bioindicators, benthic macroinvertebrates are often used to assess stream quality. Based on standard hydrobiological study techniques, the physicochemical and biological health status of the Missolé stream was assessed. Waters of the Missolé stream were found to be slightly acidic (pH: 6.23–6.26) and well-oxygenated (O2: 69.80–76.80%), with low values of temperature (T°: 23.60–24° C), turbidity (49.40–88.40 FTU) and mineralized ions (NH4+: 0–1.19 mg/L; NO2-: 0–1.61 mg/L; NO3-: 0.02–6.80 mg/L). Concerning aquatic invertebrate communities, a total of 489 individuals, grouped in two classes, eight orders and 35 families, all belonging to the phylum Arthropoda, were collected and identified. The class of Insecta was the most diversified, with seven orders and 32 families, while that of Crustacea had only one order and three families. Overall, Insecta accounted for 52.35% of the total abundance, and Decapod Crustacea was 47.65%. The three predominant families were Palaemonidae, Dytiscidae and Atyidae. Shannon and Weaver (H') and Piélou's evenness (J) indices were high at all stations and showed a slight decrease from upstream to downstream. In the same vein, the Hilsenhoff Biotic Index (HBI) classified the water quality of the Missolé stream as medium. Overall, this suburban aquatic ecosystem offers moderately favorable living conditions for aquatic biota. [ABSTRACT FROM AUTHOR]

The EU Water Framework Directive (WFD) aims to achieve good status of aquatic habitats. Classification of ecological status and identifying the stressors impacting aquatic habitats is essential for achieving this aim. Here, we evaluate different methods and indices for assessing ecological status in a hydropower-regulated river in central Norway using kick-sampling and macroinvertebrate identification through morphology and DNA as well as using environmental DNA. In Norway, the ASPT index (Average Score Per Taxon) is commonly used to evaluate ecological condition in general, although the index only provides evidence for organic pollution. We observed lower than expected diversity in the regulated river, but this was not reflected in the ASPT index, which showed "Good" to "High" status for all samples and methods. An alternative index, the IBIBI (Intercalibrated Benthic Invertebrate Biodiversity Index), returned "Bad" to "Moderate" status using the same data. The DNA-based identification methods returned in general higher species richness and somewhat higher index values than morphological species identification did. Our study exemplifies the importance of including relevant biological quality indices in WFD compliant assessments, and we advocate inclusion of a pressure-independent index like IBIBI in Norwegian river management and DNA-based identification methods for future river management in general. [ABSTRACT FROM AUTHOR]

Wastewater treatment plant (WWTP) effluents can be sources of environmental contamination. In this study, we aimed to understand whether effluents of three different WWTPs may have ecological effects in riverine recipient ecosystems. To achieve this, we assessed benthic phytobenthos and macroinvertebrate communities at three different locations relative to the effluent discharge: immediately upstream, immediately downstream and 500-m downstream the effluent discharge. Two approaches were employed: the ecological status classification as defined in the Water Framework Directive (WFD) based on biological indicators; constrained multivariate analysis to disentangle the environmental drivers (physicochemical variables and contaminants, namely metals, polycyclic aromatic hydrocarbons, pharmaceuticals, and personal care products) of ecological changes across the study sites. The results showed inconsistencies between the WFD approach and the multivariate approach, as well as between the responses of macroinvertebrates and diatoms. The WWTP effluents impacted benthic communities in a single case: macroinvertebrates were negatively affected by one of the WWTP effluents, likely by the transported pharmaceuticals (other stressors are essentially homogeneous among sites). Given the findings and the scarcity of consistent evidence on ecological impacts that WWTP effluents may have in recipient ecosystems, further research is needed towards more sustainable regulation and linked environmental protection measures. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the biological quality of the Copueno River located in Ecuador, using benthic macroinvertebrates as bioindicators as a scientific method. The specimens collected were analyzed in the Laboratory of the Provincial Government of Morona Santiago, where two biological indices were applied: Biological Monitoring Working Party (BMWP/Col) and Ephemeroptera, Plecoptera and Trichoptera (EPT), in order to determine the water quality, assigning values to the different organisms according to their level of tolerance to pollution, ranging from one 01 (the most tolerant) to ten 10 (the most sensitive). Among the results obtained, from a total of 3122 specimens collected (1391 in summer and 1731 in winter), the water quality in the dry season according to the BMWP/Col is good, and acceptable in the wet season, while according to the EPT, the quality is fair during both seasons. In conclusion, it is established that water quality decreases as it approaches the urban center; therefore, the importance of conserving water bodies is paramount in the study area. [ABSTRACT FROM AUTHOR]

The physical characteristics, soil structure, vegetation, climatic conditions, and geological structures of the floating islands in Işıklı Lake, Saklıgöl, and Karagöl located within the borders of Denizli province were examined. Additionally, the effects of environmental factors on the chemical and biological properties of these lakes were investigated. According to the research findings, 11 different benthic invertebrate species were identified. While the water quality of Işıklı Lake and Karagöl was evaluated as "Good," Saklıgöl's water quality was measured at a "Moderate" level. Habitats such as mud, algae, moss, and macrophytes stand out in the lake areas. The relationship between temperature and dissolved oxygen levels was examined, revealing that increasing water temperature reduces dissolved oxygen levels. There were variations in ammonium nitrogen content in the examined lakes, indicating the significant impact of agricultural activities, particularly in Işıklı Lake and Saklıgöl. Karagöl's lower ammonium nitrogen content demonstrates the influence of environmental factors. The correlation between lake areas and environmental factors was emphasized, highlighting the impact of wind on the vegetation of floating islands. This study contributes to the understanding and preservation of the ecological and environmental structures of lakes in Denizli. [ABSTRACT FROM AUTHOR]

The climate crisis has accelerated the frequency and intensity of droughts in the Mediterranean areas, impacting the hydrology and the ecology of their basins. Maule River is the largest watershed in the Chilean Mediterranean Zone. The growing anthropic and environmental pressure has led to changes in the structure and function of its terrestrial ecosystem. However, little is known about its influence on aquatic ecosystems. The effect of the recent extreme drought on the streamflow and its influence on water quality and the benthic macroinvertebrate community structure were evaluated in the Maule River's lower section. Beyond temporal and spatial fluctuations, healthy and permanently well-oxygenated waters prevailed in the study area. However, during the megadrought period, evidenced by a significant decrease in both precipitation and river streamflow, a greater salt wedge influence was observed, at least, in the last 7 km of the river. Although with certain asynchrony, a change in the structure of the benthic macroinvertebrate community was observed in the upstream stations. This marinization reveals an increase in the domain of marine taxa associated with the Polychaeta group and a clear decrease in typical freshwater Oligochaeta individuals. This modification in the structure of the benthic community is expected to affect the function of this estuarine system. The results presented here highlight the importance of considering the variability associated with biological components for the management of water resources and related ecosystem services, considering that one of the main problems associated with changes in land use and the pressures caused by the climate crisis is the decrease in the quality and availability of water in this and other Mediterranean basins globally. [ABSTRACT FROM AUTHOR]

The introduction of biodegradable wastes into the coastal waters has altered the water and sediment qualities and constituted stressors to the aquatic biota. This research was carried out to evaluate the impact of anthropogenic inputs on the water, sediment, and benthic fauna of the Lagos lagoon. Six sampling locations were studied from July to December, 2023. Water as well as benthic samples were collected monthly at each study station using the Hydrobios water sampler and the Van-veen grab respectively, and analyzed in the laboratory following standard procedures. The analysis of variance (ANOVA) showed that there was no significant difference (P> 0.05) in values of the pH, salinity, The sediment particle composition was dominated by mud. A total of 597 benthic macrofauna individuals comprising 3 Phyla, 4 Classes, 4 Orders, 8 Families, 8 Genera and 8 Species were sampled. The gastropods, Tympanotonus fuscatus dominated the benthic Macrofauna assemblage of the study area accounting for 56.0%. The Phylum Arthropoda was represented by one species Clibanarius africanus, recorded the least number of individuals, which contributed 0.05% of the total number of individuals collected during the Sampling period. The low abundance of the filter-feeding bivalves, the highly sensitive arthropod species as well as Pachymelania aurita in the study area may be indicative of stressed nature of the area. The existence of benthic macroinvertebrates must be guaranteed by ensuring healthy water bodies. This is possible through the implementation of environmental protective measures, which should be on the bases on the baseline condition of these pollution hotspots of the Lagos lagoon. [ABSTRACT FROM AUTHOR]

Polychlorinated biphenyls (PCBs) are a group of persistent organic pollutants (POPs) that have generated global concerns for constituting hazards in the aquatic ecosystems. Their lipophilic nature makes them to accumulate in the sediment of water bodies resulting to some negative impacts on the benthic macroinvertebrates. This study was conducted to investigate the impact of the PCBs contamination on the benthic macroinvertebrate assemblage in the study area. Benthic samples were collected at six study stations for six months using Van-veen grab sampler. Sediments samples were removed from the benthic samples into a glass container and taken to the laboratory where extraction and clean up were conducted in preparation for Gas Chromatograph-Mass Spectrometer (GC-MS) analysis. This was performed using an Agilent 5977B GC/MSD system coupled with Agilent 8860 auto-sampler, a Gas (GC-MS) equipped with an Elite-5MS (5% diphenyl/95% dimethyl polysiloxane) fused with a capillary column (30 × 0.25µm ID × 0.25 µm df). The remaining part of each benthic sample was sieved in situ through a 0.5 mm sieve and preserved in 10% formalin inside a plastic container for further analysis in the benthic laboratory following standard procedures. Results obtained from this study indicate that there is a negative linear relationship between PCB concentrations and species abundance, diversity, equitability, evenness, and richness. This suggests that PCBs contamination in sediments may pose considerable ecotoxicological risk to the community structure of benthic macroinvertebrates of the lagoon. There is also a need to improve the waste management systems to prevent the entry of PCBs and other persistent organic pollutants into the Lagos lagoon and ultimately conserve the health of this very important marine ecosystem. [ABSTRACT FROM AUTHOR]

This study was conducted in 2022 to investigate the water quality and benthic macroinvertebrate fauna of water troughs in Şarkışla, a district in the city of Sivas. Fifteen stations were selected from the most used water troughs in the district and sampling was carried out in the spring, summer, and autumn seasons during peak agricultural activities. As a result, a total of 17 taxa were identified: 4 taxa belonging to Oligochaeta, 6 species belonging to Chironomidae, 2 taxa belonging to Amphipoda, and one each belonging to Gastropoda, Hemiptera, Coleoptera, Ostracoda and Trichoptera larvae. All taxa identified are new records for the study area. In addition to benthic sampling, some physicochemical parameters of water (water temperature, pH, electrical conductivity, dissolved oxygen, total hardness, calcium, magnesium, chloride, salinity, total dissolved solids, phosphate, sulphate, nitrate nitrogen, nitrite nitrogen) were also analyzed. The similarity of the stations in terms of physicochemical parameters was analyzed by utilizing the Bray- Curtis similarity analysis. Accordingly, stations 2 and 4 were found to be the most similar, by 96.91%, and stations 3 and 13 were found to be the most different, by 66.46%. In addition, the relationship between the investigated physicochemical parameters was analyzed using the Pearson and Spearman Correlation Analysis. The relationship between the species and physicochemical parameters was revealed using the CCA Analysis. [ABSTRACT FROM AUTHOR]

Standard toxicological test methods with Hyalella azteca incorporate both lethal and sublethal (growth, reproduction) endpoints, although lethal endpoints are often favored in routine testing. However, sublethal endpoints are important to consider because they are ecologically relevant and are often more sensitive than lethality. It is difficult to achieve robust data for reproduction in H. azteca because high biological variability is associated with reproductive yield, likely due to complex interactions in mate selection, which can add to the variability in brood sizes that females produce. In addition, effects on reproduction often co‐occur with effects on growth, making it difficult to differentiate effects on growth from those on reproduction in standard tests initiated with juveniles. The present study characterized the reproductive capacity of H. azteca by investigating the role of sex ratios in reproductive yield. Experiments were initiated in the absence of toxicants with sexually mature (6–8‐week‐old) individuals that were placed in different female‐to‐male ratios (1:1, 2:3, 3:2, and 7:3). Reproduction was monitored during weekly static renewals for 7 weeks. The results indicated that a higher female:male ratio (seven females to three males) improved reproductive success and lowered biological variability in reproduction. In addition, the body lengths and weights of newly mature amphipods were used to create a size distribution to aid in the identification of small female amphipods. Based on the results of our study, a novel reproductive toxicity test method is proposed that begins with sexually mature amphipods in a ratio of seven females to three males to minimize reproductive variability in amphipods and to enable a more effective assessment of contaminants using reproduction as a highly sensitive endpoint. However, evaluation of this novel method with toxicants is needed to demonstrate that results are comparable to standard methods. Environ Toxicol Chem 2024;43:712–722. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

This study investigated the species, density, biomass and physicochemical factors of benthic macroinvertebrates in Hongze Lake from 2016 to 2020. Redundancy analysis (RDA) was used to analyze the relationship between physicochemical parameters and the community structure of macroinvertebrates. Macroinvertebrate-based indices were used to evaluate the water quality conditions in Hongze Lake. The results showed that a total of 50 benthic species (10 annelids, 21 arthropods and 19 mollusks) were collected. The community structure of benthic macroinvertebrates varied in time and space. The dominant species were Limnodrilus hoffmeisteri (L.hoffmeisteri), Corbicula fluminea (C.fluminea), Nephtys oligobranchia (N.oligobranchia). In 2016, arthropods such as Grandidierella sp. were the dominant species of benthos in Hongze Lake while annelids and mollusks dominated from 2017 to 2020, such as L.hoffmeisteri, N.oligobranchia, C.fluminea. The benthic fauna of Chengzi Lake and Lihewa District were relatively abundant and showed slight variation, while the benthic macroinvertebrates of the Crossing the water area were few and varied greatly. RDA showed that changes in benthic macroinvertebrate structure were significantly correlated with dissolved oxygen (DO), Pondus Hydrogenii (pH) and transparency (SD). The Shannon Wiener, Pielou, and Margalef indices indicate that Hongze Lake is currently in a moderately polluted state. Future studies should focus on the combined effects of various physicochemical indicators and other environmental factors on benthic communities. [ABSTRACT FROM AUTHOR]

Globally, monitoring of the surface waters is largely limited to the physico-chemical analysis of water in rivers and lakes. Sediment state in the aquatic systems including sediment chemical content or the structure and diversity of benthic communities or ecotoxicological studies with natural sediments remains largely overlooked by the monitoring programs. Hence we assessed the potential toxicity of three riverine sediments on the life-cycle traits (emergence and reproduction) of midge Chironomus riparius via an ecotoxicological testing method over two generations (according to OECD test 233 guidelines). In addition, the riverine sediments were spiked with polyamide (nylon) microplastic particles (1 g kg−1) to analyze an additive effect of microplastic on the sediment toxicity. As model river systems, three rivers (Karchaghbyur, Gavaraget, Argichi) in the Lake Sevan basin (Armenia) were selected. Results of ecotoxicity testing were compared with the indices of water quality (derived from the physico-chemical analysis) and the indices of the ecological status of the rivers (derived from the analysis of benthic communities). The results of testing demonstrated an unexpectedly low emergence of midges after the first generation exposed to the sediment of the river having ‘’good ecological status’’ - the Argichi. Sediments of the Karchaghbyur and Gavaraget rivers impeded the emergence and reproduction of midges after the second generation. An addition of polyamide particles to the sediments did not significantly affect the life-cycle traits of C. riparius indicating the primary effect of the sediments’ condition. The discrepancy of biotesting result with that of the other two methods (which indicated ‘’average water quality’’ and “good ecological status”) underlies the importance of designing more comprehensive monitoring programs for better assessment and protection of aquatic systems and resources.

Invasive species represent a significant threat to native biodiversity. The Himalayan Balsam Impatiens glandulifera is an annual plant, which is invasive in Europe and often inhabits the riparian zone. It produces several secondary metabolites causing, for example, growth inhibition of terrestrial plants and invertebrates. One of these metabolites is the quinone 2-methoxy-1,4-naphthoquinone (2-MNQ). The compound gets washed out from the above-ground parts of the plant during precipitation and may then leach into nearby waterbodies. Despite some evidence for the allelopathic effect of plant secondary metabolites on terrestrial invertebrates, little is known about how 2-MNQ affects the survival or development of aquatic dipteran larvae, despite the importance of this functional group in European freshwaters. Here, we investigated the effects of 2-MNQ on larvae of the river keystone species Chironomus riparius in acute and chronic scenarios. The toxicity of 2-MNQ towards the first and the fourth larval stage was determined in a 48-hour acute exposure assay. We show that 2-MNQ has a negative impact on the development, growth and survival of C. riparius. The LC50 of 2-MNQ was 3.19 mg/l for the first instar and 2.09 mg/l for the fourth instar. A ten-day chronic exposure experiment, where the water was spiked with 2-MNQ, revealed that 2-MNQ had a significantly negative impact on larval body size, head capsule size, body weight, development and survival. These results demonstrate the negative impact of the secondary metabolite 2-MNQ from the terrestrial plant I. glandulifera on a crucial macroinvertebrate inhabiting the adjacent stream ecosystem in riverine ecosystems. This may lead to a decline in population size, resulting in cascading effects on the food web. [ABSTRACT FROM AUTHOR]

Many river ecosystems in the boreal zone have faced remarkable changes due to intensive human activities, including land‐use changes in the catchments and channelization. Recently, restoration efforts have increased, hoping to restore a more natural hydromorphology. We studied the community structure of benthic macroinvertebrates (zoobenthos) in seven rivers in Eastern Finland, using samples that covered pre‐ and post‐restoration periods, to examine how environmental metrics relate to the zoobenthos community structure, and the fatty acid (FA) composition and content of Ephemeroptera, Plecoptera, and Trichoptera nymphs and larvae. We also analyzed the FA composition and content of land‐locked salmon (Salmo salar m. sebago) in three of the rivers and brown trout (Salmo trutta) in two of the rivers. Zoobenthos communities differed significantly among most of the rivers: 24% of the differences between the zoobenthos communities were driven by water quality parameters related to the loading of terrestrial organic matter (water color, pH, and iron concentration). Temporal changes in zoobenthos communities could not be fully attributed to restorations. The FA composition of zoobenthos was mostly explained by phylogenetic origin (47%). However, especially mayfly Heptagenia sulphurea (Ephemeroptera: Heptageniidae) had variable FA composition and content among the rivers suggesting an environmental quality indicator role for this species. FA composition and content of salmonids were mostly size‐dependent (24%), but river identity also influenced their FA composition (22%). Our results indicate that water quality affects the availability of essential FAs for consumers by altering the zoobenthos community structure and their FA composition and content. [ABSTRACT FROM AUTHOR]

Beach seine fishery provides a means of livelihood to many households in Africa and it is widely practiced in the coastal communities of Ghana due to the relatively cheaper operational cost. However, the small mesh sizes of beach seine nets and fishing activities that involve dragging a net through the nearshore seabed tend to destroy fish breeding grounds and capture juvenile fish and non‐target benthic macroinvertebrates, which get discarded. This study investigated the impact that before and after closed season for beach seine fishing had on macroinvertebrates species diversity indices at two Ghanaian beaches with different fishing pressures. The study was carried out at OLA and Sisimbo Beaches located in the Central Region of Ghana, taking advantage of the statutory 1‐month national fishing closed season in July 2022. Six (6) replicate sediment samples were taken at each beach after landing by beach seine fishers every month for 6 months, from April to June, and August to October, representing before and after closed season, respectively. Benthic macroinvertebrates were retrieved from the samples using appropriate protocols and subjected to indirect (Shannon, Simpson, Rényi) and direct (species abundance models, species accumulation models, multivariate statistics) measures of species diversity analyses. The indirect species diversity indices increased monotonically the following 2 months after closed season but reduced in the third month after closed season at both beaches. Conversely, the direct measures of diversity indices revealed that closed season for beach seine fishing improved species numbers and richness at both study beaches. This is the first report on the impact of a closed season on macroinvertebrates in any African country. [ABSTRACT FROM AUTHOR]

Water resources management requires comprehensive and integrated approaches that jointly consider hydrological, ecological and social factors. The assessment of lakes' environmentally minimum water level is a critical tool for the sustainable management and protection of their ecosystems. This work combines the morphological, hydrological and biological factors of a Mediterranean lake (Lake Volvi, northern Greece) to assess its environmentally minimum water level. Initially, the morphological characteristics of the lake's bottom were analyzed, with consideration given to the protection of the lake's ecosystem and to the need to meet the water requirements for economic activities. Then, a hydromorphological analysis was conducted, relying on the surface water inflows to the lake from its hydrological catchment and the lake's water level -volume relationship. In addition, the water level requirements of the biological communities of macrophytes, benthic macroinvertebrates, and fish, as revealed after samplings were taken from the lake's littoral zone, are considered. Based on the above methodologies, the environmentally minimum water level of Lake Volvi is proposed to be lowered by as much as 35.8 m from February to May and 35.3 m from June to January in order to maintain the ecological integrity of the lake and the sustainable use of its water resources. The present study establishes a foundation for informed water resource management; however, ongoing research can improve methodologies and address emerging questions, fostering advancements in sustainable water management practices. [ABSTRACT FROM AUTHOR]

Thousands of kilometers of waterways and associated aquatic communities around the world are negatively impacted by mine drainage (MD). This study investigated the effects of contamination from abandoned mining operations on benthic macroinvertebrate and fish communities in a second-order stream using rapid bioassessment protocols (RBPs). The study sampled six sites along Tar Creek, in Ottawa County, Oklahoma, USA, which are negatively impacted by contamination from abandoned underground lead and zinc mining operations. Water quality samples were collected in conjunction with RBPs at each site during the summer months in 2018, 2020, and 2021. Two sites located in the mining-impacted area had the most impaired benthic macroinvertebrate and fish communities, with significantly lower taxa richness, Shannon diversity, and total RBP metric scores compared with regional reference conditions (p < 0.05). The impairments at the most upstream site (TC1) were attributed to waste material from the mining operations, which generate elevated concentrations of aqueous metals and highly erodible streambeds. Additionally, TC2, immediately downstream of TC1, regularly received 3000 L/min of untreated artesian flowing MD that increased aqueous iron and lead concentrations and formed iron hydroxide precipitates that coated the bottom of the streambed. Fish and benthic macroinvertebrate communities showed increasing RBP metric scores with distance from the mining-impacted area. Despite chronic contamination from abandoned mining operations, the stream still has an appropriate biological community downstream that can serve as a source pool for repopulation upstream if the contamination were to be remediated. [ABSTRACT FROM AUTHOR]

Copyright of Boletín Científico Centro de Museos de Historia Natural is the property of Universidad de Caldas 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.)

Copyright of Revista de Investigación e Innovación Agropecuaria y de Recursos Naturales is the property of Revista de Investigacion e Innovacion Agropecuaria y de Recursos Naturales RIIARn 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.)

Urban sprawl leads to the degradation of aquatic environments and, consequently, to the destruction of biodiversity. With the aim of highlighting the distribution profile of benthic macroinvertebrates in the city of Yaoundé and its surroundings according to the level of degradation, this study was carried out in seven rivers. A total of 144 taxa of benthic macroinvertebrates, belonging to 74 families, 15 orders, five classes, and three phyla, were collected from seven rivers in urban, peri-urban, and forest environments on Yaoundé and its surroundings. The self-organizing map (SOM) analysis tool was used to group the collected taxa from all stations into three clusters or affinity cores. The indicator value analysis (IndVal) method was employed to determine, based on their ecological preferences, which organisms were most likely to belong to each group. Out of the 144 collected taxa, only 44 were indicated to represent the three different groups. Thus, three communities were defined: the Hydropsyche community, with Hydropsyche sp. as the predominant taxon in Group III, characterizing well-oxygenated and low-mineralized stations; the Hydrocyrius community, where the species Hydrocyrius sp. predominates in Group I, describing stations with low oxygenation and moderate mineralization; and the Lumbriculidae community, where Lumbriculidae is the taxon associated with environments with high mineralization and critical oxygenation. These two methods contribute to the biomonitoring of tropical aquatic environments, firstly by grouping organisms by affinity and then identifying those that reflect the environment conditions. This facilitates the detection of changes in the quality of hydrosystems and guides management and conservation efforts.

Abstract Benthic macroinvertebrates are integral parts of inland waters, inhabiting a diversity of aquatic ecosystems where communities are spatially structured. Macroinvertebrates of some Mediterranean regions such as North Africa are still not well studied. Due this reason we proposed study the community structure in water bodies located in Northeastern Algeria. For this objective, we sampled 12 different kind of water bodies, two dams, three rivers, and seven streams during the period from October 2020 to September 2021. To biotic and abiotic data, a redundancy analysis (RDA) was applied with the aim of determine the role of both kind of variables for grouping the sites. Also, two types of Null models were considered: species co-occurrence and niche sharing for study the potential associations between species reported. Redundancy analysis showed that water velocity and conductivity were the main drivers of community structure of macroinvertebrates. The species co-occurrence results reveal that species associations are ramdom, except for two sites: El fadjoudj and Ain ben baida corresponding to Seybouse river. At the same time, there is no niche sharing and in consequence, there is no interspecific competition except in the two sites: Salah Salah Salah stream and Bouhamdane dam. The results revealed similarities with other similar studies for Algerian rivers and dams, and with other similar water bodies with Mediterranean climate.

Mountain streams harbor unique biodiversity and provide essential ecosystem services to human societies. Yet, these ecosystems face numerous threats, such as the construction of dams and land use changes, leading to rapid habitat degradation, water pollution, and biodiversity loss. In this study, we assess the effect of irrigation dams on mountain riverine biota using traditional biotic indices and trait-based approaches. We selected diatom and macroinvertebrate communities surveyed between 2015 and 2017 in mountain streams located in different regions in northern Spain (Cantabrian Cordillera, Iberian System, and Pyrenees) under natural and altered flow conditions (i.e., downstream of irrigation dams). Hydrological and biological changes related to the presence of dams, the mountain range, and the interaction between these two factors were identified. Summer flows, frequency of high flow events, and minimum annual flows timing were significantly affected by irrigation dams, independently of the region. Winter flows, the magnitude of high flow extremes, and the number of flow rises and falls varied significantly with the dam-mountain range interaction. The frequency and duration of flow pulses depended on the mountain range only. In the Cantabrian Cordillera, a region with larger reservoirs (>150 hm3), impacted sites showed a marked inversion of the seasonal flow patterns (i.e., increased summer flows but reduced winter flows). In the other mountain ranges, reservoirs had smaller storage volumes and multiple purposes, causing significant flow change frequency variations. Diatom traits, taxonomic richness, diversity, and IPS score varied with dam presence and mountain ranges, while macroinvertebrate traits and biotic indices responded weakly. These findings suggest that diatom communities might be more sensitive to hydrological alteration, while macroinvertebrates might be more influenced by space-related factors, such as biogeography and dispersal, overriding dam-related impacts. Furthermore, dam-related changes in ecosystems may depend not only on the presence of dams and their characteristics (e.g., reservoir size and operation), but also on local conditions and biogeography. Our findings emphasize that, when using pre-existing biomonitoring datasets, although some dam-related patterns emerge (e.g., with diatoms), other patterns may be constrained by the datasets’ low spatio-temporal coverage and taxonomic resolution, highlighting the need of well-structured study designs.

This study introduces the AquaShan Index, an innovative approach to assessing river health, which integrates biological indicators with key environmental variables. This index represents an advancement over traditional methods, like the Shannon Diversity Index, by including both species diversity and environmental factors such as dissolved oxygen, pH, and water temperature. Utilizing data from the Stream/River Ecosystem Survey and Health Assessment in South Korea, covering 5,952 data over three years, the study combines species data of benthic macroinvertebrates with environmental parameters, applying Random Forest analysis to weight these variables. The AquaShan Index formula incorporates species’ pollution tolerance scores, offering a nuanced perspective on ecosystem resilience to environmental stressors. Our results show a wide range of river health conditions, with the AquaShan Index demonstrating greater sensitivity and specificity in identifying ecological impairments compared to traditional indices. The inclusion of pollution tolerance scores and environmental variables provides a more comprehensive assessment of river health, revealing a higher number of sites with ecological challenges than previously identified. The AquaShan Index's adaptability and comprehensive approach make it a valuable tool for informed decision-making in river conservation and management, offering an enhanced methodology for assessing and sustaining river ecosystem health.

Despite peri-urban areas being crucial for ecosystem service provisioning, they usually become degraded, as they are burdened with effluents from urban production activities. Such is the case of Laspias River (Thrace, Greece), where a series of diffuse and point pollution sources are met throughout its course, neglecting the fact that it discharges into a protected area. In an attempt to assist possible management implications in this less-researched river, two years of investigative monitoring provided the insight to test the effect of abiotic parameters in the benthic invertebrate biota and water quality, in turn. The results revealed an avalanche of pressures, where nutrients and organic pollution loads diminish richness and biodiversity, losing any temporal or seasonal pattern, resulting in biotic (taxonomic/functional) homogenization. The river is at a tipping point, and tailored measures must be designed and implemented immediately. [ABSTRACT FROM AUTHOR]

Groundwater discharge into streams influences the biodiversity and health of groundwater-dependent stream ecosystems. These localized upwelling zones may act as biodiversity hotspots, or areas with a heightened amount of endemic species richness and abundance when compared to the surrounding locality. This input water creates environments with unique chemical compositions and water temperatures that serve as ideal habitat for various species within the ecosystem. Although difficult to identify and sample, these underwater groundwater–surface water interaction zones are important for fish spawning, benthic macroinvertebrate biodiversity, microbial communities, and aquatic and riparian vegetation. In this review, we highlight the groundwater characteristics that influence stream biodiversity and community structure. We argue for the importance of increased research on biodiversity indicators of groundwater upwelling zones as well as more public involvement through citizen science practices on the indirect and direct relationships between groundwater and dependent stream ecosystems. The unique characteristics that differentiate groundwater from surface water in a stream environment can be ideal conditions for fish, benthic macroinvertebrates, vegetation, and bacteria. Groundwater upwelling zones act as biodiversity hotspots that may have a key role in the overall health of a stream community. Research that revolves around groundwater-stream interactions is limited and difficult to accomplish, with no standardized hydrologic or ecological methods of measurement. It is crucial to not only make measurement collection practices and data interpretation commonplace but increase awareness of the relationship between groundwater-stream interactions and biodiversity hotspots. [ABSTRACT FROM AUTHOR]

Copyright of Acta Zoologica Lilloana is the property of Fundacion Miguel Lillo 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.)

Macroinvertebrates are bioindicators of sediment quality and serve as a reference for the status of a given ecosystem. However, unregulated anthropogenic activities affect macroinvertebrates and their ecological functions. This study aims to evaluate the sediment characteristics and effect of human-induced stressors on macroinvertebrates community structure in Chanomi Creek, Niger Delta. Sediment and macroinvertebrate samples were collected monthly between March 2020 and August 2021 using a Van Veen grab. The samples were preserved for further analyses in the laboratory following standard procedures. Among the sediment characteristics analysed, only pH, acidity, sediment texture and BTEX showed significant differences (P < 0.05) across seasons. Despite PAH and BTEX levels being below the Department of Petroleum Resources’ recommended limits, sediment pH ranged from 4.07 to 5.67, indicating acidity. Sandy-clay particles dominated the sediment, potentially causing lower nutrient and organic matter concentrations. The study recorded 968 individuals represented by 27 species, 23 genera, 18 families, 14 orders, 7 classes and 4 phyla. The phylum Mollusca recorded 77.5%, Arthropoda 19.6%, Annelida 2.5% and Echinodermata 0.4% of the fauna composition with Tympanotonos fuscatus as the dominant species (32.5%). The macroinvertebrate assemblage recorded low diversity while AZTI’s Marine Biotic Index and Bentix Index indicated that the macroinvertebrate assemblage in the creek is slightly disturbed. These benthic indices revealed an overall perturbed ecosystem from various environmental stressors. These results provide comprehensive understanding of the overall health, diversity and functioning of the macroinvertebrate community within the creek. Implementation of effective measures to address anthropogenic stressors in brackish ecosystems is needed. [ABSTRACT FROM AUTHOR]

The ongoing global environmental change poses a serious threat to rivers. Comprehensive knowledge of how stressors affect biota is critical for supporting effective management and conservation strategies. We evaluated the major gradients influencing spatial variability of freshwater biodiversity in continental Spain using landscape-scale variables representing climate, land use and land cover (LULC), flow regime, geology, topography, and diatom (n = 117), macroinvertebrate (n = 441), and fish (n = 264) communities surveyed in minimally impacted streams. Redundancy analysis identified the environmental factors significantly contributing to community variability, and specific multivariate analyses (RLQ method) were used to assess trait–environment associations. Environmental variables defined the major community change gradients (e.g., mountain–lowland). Siliceous, steep streams with increased precipitation levels favored stalked diatoms, macroinvertebrates with aquatic passive dissemination, and migrating fish. These traits were replaced by adnate diatoms, small macroinvertebrates, and non-migratory fish in lowland streams with warmer climates, calcareous geology, agriculture, and stable flow regimes. Overall, landscape-scale environmental variables better explained fish than diatom and macroinvertebrate community variability, suggesting that these latter communities might be more related to local-scale characteristics (e.g., microhabitat structure, substrate, and water physicochemistry). The upslope environmental gradient of river networks (e.g., slope, temperature, and LULC changes) was paralleled to the observed taxonomy-based and trait-based spatial variability. This result indicates that global change effects on riverine biodiversity could emerge as longitudinal distribution changes within river networks. Implementing management actions focusing simultaneously on water temperature, hydrological regime conservation (e.g., addressing LULC changes), and river continuity might be the best strategy for mitigating global change effects on river biodiversity. [ABSTRACT FROM AUTHOR]

Numerous actions have been undertaken by farmers to attenuate the impact of agricultural activities on aquatic ecosystems. The identification of biomarkers that respond quickly to water quality improvement could facilitate the assessment of adopted alternative practices and help maintain mobilization among stakeholders. We evaluated the potential of the comet assay, a biomarker of genotoxic effects, using a freshwater mussel, Elliptio complanata, as a model animal. The frequency of DNA damage was assessed in hemocytes of mussels collected from a pristine habitat and caged for 8 weeks in the Pot au Beurre River, a tributary of the fluvial Lake St.‐Pierre (Quebec, Canada) impacted by agricultural activities. We found that the level of DNA damage naturally induced in mussel hemocytes was low and showed very limited variations over time. Compared with these baseline levels and to laboratory controls, we observed a doubling in DNA alterations in mussels exposed to agricultural runoff in the third branch of the Pot au Beurre River. The genotoxic response was significantly lower in mussels caged in the first branch of the Pot au Beurre River, where longer stretches of shoreline have been restored as buffer strips. Glyphosate, mesotrione, imazethapyr, and metolachlor were the main discriminant pesticides between these two branches. Metolachlor was found in sufficient concentrations to induce DNA damage, but it is more likely that the observed genotoxicity was the result of a "cocktail effect," that is, the cumulative contribution of coexisting genotoxicants including the above‐mentioned herbicides and ingredients in their formulation. Our findings suggest that the comet assay is a sensitive tool for the early detection of changes in water toxicity following the adoption of agricultural beneficial practices. Environ Toxicol Chem 2023;42:2201–2214. © 2023 Crown copyright and The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. This article is published with the permission of the Controller of HMSO and the King's Printer for Scotland. [ABSTRACT FROM AUTHOR]

Residual concentrations of pesticides are commonly found outside the intended area of application in Ontario's surface waters. Periphyton are a vital dietary component for grazing organisms in aquatic ecosystems but can also accumulate substantial levels of pesticides from the surrounding water. Consequently, grazing aquatic organisms are likely subjected to pesticide exposure through the consumption of pesticide‐contaminated periphyton. The objectives of the present study were to determine if pesticides partition into periphyton in riverine environments across southern Ontario and, if so, to determine the toxicity of pesticides in periphyton when fed to the grazing mayfly Neocloeon triangulifer. Sites with low, medium, and high pesticide exposure based on historic water quality monitoring data were selected to incorporate a pesticide exposure gradient into the study design. Artificial substrate samplers were utilized to colonize periphyton in situ, which were then analyzed for the presence of approximately 500 pesticides. The results demonstrate that periphyton are capable of accumulating pesticides in agricultural streams. A novel 7‐day toxicity test method was created to investigate the effects of pesticides partitioned into periphyton when fed to N. triangulifer. Periphyton collected from the field sites were fed to N. triangulifer and survival and biomass production recorded. Survival and biomass production significantly decreased when fed periphyton colonized in streams with catchments dominated by agricultural land use (p < 0.05). However, the relationship between pesticide concentration and survival or biomass production was not consistent. Using field‐colonized periphyton allowed us to assess the dietary toxicity of environmentally relevant concentrations of pesticide mixtures; however, nutrition and taxonomic composition of the periphyton may vary between sites. Environ Toxicol Chem 2023;42:2143–2157. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

Aquatic habitats within the St. Louis River estuary were impacted when developing the Duluth-Superior Harbor (MN/WI USA) and through decades of unregulated industrial and municipal discharge. An effort to remediate and restore sediment quality in the harbor began by implementing projects designed to address Beneficial Use Impairments (BUI) identified in this Area of Concern. Habitat restoration in the 21st Avenue West project site was implemented to improve overall aquatic community health and address a degradation of benthos BUI. Restoration objectives focused on creating more complex bathymetric surfaces and mitigating contaminant exposure by capping with clean dredged material. Before and after construction, samples were collected to assess the benthic community within 21st Avenue West compared to results from least-impaired, reference locations. A scaled trimetric index (s-TMI), scored between 0 and 1, was used to track an impaired benthic community before and after construction. A median s-TMI value for 21st Avenue West prior to construction (value = 0.51) improved following restoration (site median = 0.65), reaching a site-wide value that was not significantly different from the least impaired removal target (reference median = 0.68, when calculated from pooled reference data). Results from post construction sample collections at 21st Avenue West suggest macroinvertebrate community index scores increased by more than 10% two years following construction. These results indicate that the 21st Avenue West habitat restoration effort successfully reached a degradation of benthos BUI goal and demonstrates that dredge material is a cost-effective alternative for construction. [ABSTRACT FROM AUTHOR]

Benthic macroinvertebrates are commonly used for assessment of water quality. Usually, these insects in rivers are present, easily collected, not moving much and it is easy to detect kinship. Benthic macroinvertebrates can also show changes in water quality and as sensitive indicators of environmental change are used. Jajrud River originated from the Elburz Mountains in northern Tehran. A sampling of Jajrud River benthic macroinvertebrate organisms from a Surber sampler device with an area of 900 cm2 and mesh size of 250-micron was repeated three times at each station. Physicochemical parameters including Elevation, Depth, Flow Velocity (WatFlow), Water Temperature (WatTem), Turbidity, Total Suspended Solids (TSS), Electrical conductivity (EC), Fecal Coliform, Phosphate, Nitrate, Nitrite, Ammonium, Dissolved oxygen (DO), pH, Chemical Oxygen Demand (COD) Biochemical Oxygen Demand (BOD) were measured. Habitat parameters such as Epifaunal Substrate (EFAC), Embeddedness (Embed), Velocity and Depth Regimes (Vel), sediment deposition (Sedimen), Channel Flow Status (Channelf), Channel Alteration (Channelt), Frequency of Riffles (Freq), Bank Stability (Bankstu), Vegetative Protection (Veg) and Riparian Vegetative Zone Width (RipaVeg) were reviewed. Then according to bioassessment protocols and ratings based on a zero to 20, for relationship between physicochemical and habitat parameters with an abundance of benthos grouping and assessment of water quality, from CANOCO software and principal component analysis (PCA) was used. The results showed that the water quality in the downstream Jajrud is unfavorable and appropriate management measures should be taken to improve the river's water quality. [ABSTRACT FROM AUTHOR]