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Microplastics are widespread pollutants, but few studies have linked field prevalence in organisms to laboratory uptakes. Aquatic filter feeders may be particularly susceptible to microplastic uptake, with the potential for trophic transfer to higher levels, including humans. Here, we surveyed microplastics from a model freshwater shrimp, common caraidina (Caridina nilotica) inhabiting the Crocodile River in South Africa to better understand microplastic uptake rates per individual. We then use functional response analysis (feeding rate as a function of resource density) to quantify uptake rates by shrimps in the laboratory. We found that microplastics were widespread in C. nilotica, with no significant differences in microplastic abundances among sampled sites under varying land uses, with an average abundance of 6.2 particles per individual. The vast majority of microplastics found was fibres (86.1%). Shrimp microplastic accumulation patterns were slightly higher in the laboratory than the field, where shrimp exhibited a hyperbolic Type II functional response model under varying exposure concentrations. Maximum feeding rates of 20 particles were found over a 6 h feeding period, and uptake evidenced at even the lowest laboratory concentrations (~10 particles per mL). These results highlight that microplastic uptake is widespread in field populations and partly density dependent, with field concentrations corroborating uptake rates recorded in the laboratory. Further research is required to elucidate trophic transfer from these taxa and to understand potential physiological impacts. [ABSTRACT FROM AUTHOR]

Given the widespread use as flame retardants, plasticizers, and organophosphate esters (OPEs) received increasing scientific interests on their occurrence and ecotoxicological research progress. This review comprehensively conducted bibliometric analysis and surveyed the OPEs occurrence in aquatic ecosystem (water, sediment, and aquatic organisms) and human-related (drinking water and sewage) over the past decade to unraveling knowledge gaps. The OPEs concentrations in water, sediment were at the range of not detected (n.d.) or several to hundreds ng/g or ng/L and exhibited landuses-specific characteristics. The electronic waste (e-waste) processing activities and sewage discharge were identified as point sources of OPEs in aquatic environment. Emission source intensity, water chemistry, and content of organic carbon were important for the partition and transfer processes of OPEs in the water, as well as hydrophobicity of OPEs dominating the absorption on the organic matter. Degradation, especially photodegradation and reductive degradation, has application potential in improving removal efficiencies of chlorinated-OPEs (Cl-OPEs) being reluctant to degrade. Generally, most surveyed OPEs have negligible ecological and health risks, whereas those OPEs with moderate threats or chronic effects on aquatic ecosystem should gain more attention. This review elucidates the status of OPEs pollution in water and highlights the need for more transport and degradation studies on traditional and emerging OPEs and metabolites to further identify potential threats on aquatic ecosystem. [ABSTRACT FROM AUTHOR]

The urgent need for technological innovation to combat water pollution underscores the significance of biosorption as a potential solution. The success of biosorption hinges on the careful selection of a suitable biosorbent. Biofilms, composed of microbial communities, emerge as a promising alternative due to their expansive adsorption capacity and ready availability. In practical applications, biosorption is often executed at pollutant concentrations lethal to microbes. Consequently, comprehending the biosorption potential of biofilms with deceased microbes becomes imperative. Notably, biofilms with deceased microbes offer the added advantage of minimizing the risk of pathogenic microbial contamination. Despite this, studies are scarce comparing biosorption between intact biofilms and those with deceased microbes. This comparative analysis could enhance the feasibility of biofilms in biosorption as an eco-aquatic technology for alleviating aquatic pollution. This study aims to scrutinize the biosorption characteristics of intact biofilm (with living microbes) and autoclaved biofilm (with deceased microbes). The methods employed for analyzing biosorption characteristics encompass examining electric charge properties, FTIR spectra analysis, ion adsorption, and ion desorption. The model ions chosen for this study are K+ (monovalent ion) and Mg2+ (divalent ion). Results indicate that the biofilm's electric charge properties and adsorption capacity remain relatively unchanged post-autoclaving. Based on these findings, it can be concluded that biofilms, whether intact or autoclaved, present substantial potential as biosorbents in the advancement of eco-aquatic technology for mitigating water pollution. [ABSTRACT FROM AUTHOR]

Antibiotic-resistant bacteria (ARB) adhesion onto plastic substrates is a potential threat to environmental and human health. This current research investigates the prevalence of two relevant human pathogens, Staphylococcus spp. and Klebsiella spp., and their sophisticated equipment of antibiotic-resistant genes (ARGs), retrieved from plastic substrates submerged into an inland water body. The results of microbiological analysis on selective and chromogenic media revealed the presence of colonies with distinctive phenotypes, which were identified using biochemical and molecular methods. 16S rDNA sequencing and BLAST analysis confirmed the presence of Klebsiella spp., while in the case of Staphylococcus spp., 63.6% of strains were found to be members of Lysinibacillus spp., and the remaining 36.3% were identified as Exiguobacterium acetylicum. The Kirby–Bauer disc diffusion assay was performed to test the susceptibility of the isolates to nine commercially available antibiotics, while the genotypic resistant profile was determined for two genes of class 1 integrons and eighteen ARGs belonging to different classes of antibiotics. All isolated bacteria displayed a high prevalence of resistance against all tested antibiotics. These findings provide insights into the emerging risks linked to colonization by potential human opportunistic pathogens on plastic waste commonly found in aquatic ecosystems. [ABSTRACT FROM AUTHOR]

This study investigated iron (Fe) accumulation in South Kalimantan's coastal swamp wetlands ecosystem, utilizing giant mudskipper fish as indicators of heavy metal pollution. By analyzing Fe levels in water, sediment, and fish organs over time, insights into its effects on the environment and human health were gained. Furthermore, through Atomic Absorption Spectrometry, Fe concentrations in Kuala Lupak's coastal wetland were measured, revealing significant correlations between Fe levels in water, sediment, and fish tissues. These results enhance our understanding and inform better management strategies. Anthropogenic and natural sources contribute to the accumulation of heavy metals, particularly Fe, with anthropogenic pollution being the most dominant. This study presented the escalating concentrations of Fe within the Kuala Lupak estuary and raised concerns regarding the ecological and human health implications. Continuous monitoring, source identification, public awareness, regulations, remediation, and long-term exploration are essential for addressing heavy metal pollution and its ecological impact. Therefore, valuable insights are provided for environmental management and conservation efforts. [ABSTRACT FROM AUTHOR]

The rapid inclusion of zinc oxide nanoparticles (ZnO NPs) in nanotechnology-based products over the last decade has generated a new threat in the apprehension of the environment. The massive use of zinc nanosized products will certainly be disposed of and be released, eventually entering the aquatic ecosystem, posing severe environmental hazards. Moreover, nanosized ZnO particles owing the larger surface area per volume exhibit different chemical interactions within the aquatic ecosystem. They undergo diverse potential transformations because of their unique physiochemical properties and the feature of receiving medium. Therefore, assessment of their impact is critical not only for scavenging the present situation but also for preventing unintended environmental hazards. Algae being a primary producer of the aquatic ecosystem help assess the risk of massive NPs usage in environmental health. Because of their nutritional needs and position at the base of aquatic food webs, algal indicators exhibit relatively unique information concerning ecosystem conditions. Moreover, algae are presently the most vital part of the circular economy. Hence, it is imperative to understand the physiologic, metabolic, and morphologic changes brought by the ZnO NPs to the algal cells along with the development of the mechanism imparting toxicity mechanism. We also need to develop an appropriate scientific strategy in the innovation process to restrain the exposure of NPs at safer levels. This review provides the details of ZnO NP interaction with algae. Moreover, their impact, mechanism, and factors affecting toxicity to the algae are discussed. [ABSTRACT FROM AUTHOR]

Several types of contaminants are anthropogenically introduced into natural aquatic ecosystems and interact with other chemicals and/or with living organisms. Although metal toxicity alone has been relatively well studied, the toxic metal ion effects in the mixture have been thoroughly studied only during the last decades. This review focuses on the published reciprocal effects of different metals on different species of algae, together with describing their toxic effects on studied parameters. Phytoplankton as a bioindicator can help to estimate the reciprocal metal risk factor. Many methodologies have been developed and explored, such as the biotic ligand model (BLM), concentration addition (CA), independent action (IA), sensitivity distribution of EC50 species sensitivity distribution (SSD curves), and others, to study reciprocal metal toxicity and provide promising results, which are briefly mentioned too. From our review, we can commonly conclude the following: Zn acted antagonistically with most heavy metals (Al, Cu, Cd, and Ni). The Cu interaction with Cd, Fe, and Pb was mostly antagonistic. Cd showed synergistic behaviour with Hg, Cu, Zn, and Pb and antagonistic behaviour with Co and Fe in many cases. Methods and techniques need to be developed and optimised to determine reciprocal metal toxicity so that the ecotoxicological predictions made by using phytoplankton can be more accurate and related to real-time toxic metals risks to the aquatic ecosystem. This is the main objective of ecotoxicological tests for risk assessment. Understanding how metals enter algal cells and organelles can help to solve this challenge and was one of the main parts of the review. [ABSTRACT FROM AUTHOR]

IntroductionAnalyzing the correlation between planktonic eukaryotic communities (PECs) and aquatic physicochemical parameters (APPs) provides important references for predicting the impact of climate change and human activities on aquatic ecosystems.MethodsTo assess the influence of seasons and APPs on PEC structures in lakes and rivers, we utilized high-throughput sequencing of the 18S rRNA gene to analyze PEC structures in a lake and seven rivers in the Chaohu Lake Basin and analyzed their correlations with APPs.ResultsOur results revealed that PEC structure was significantly affected by season, with the highest α-diversity observed in summer. Furthermore, we identified several APPs, including water temperature, conductivity, dissolved oxygen, pH, phosphate, total phosphorus, trophic level index (TLI), nitrate, ammonia nitrogen, and total nitrogen, that significantly influenced PEC structures. Specifically, we found that Stephanodiscus hantzschii, Simocephalus serrulatus, Cryptomonas sp. CCAC_0109, Pedospumella encystans, Actinochloris sphaerica, Chlamydomonas angulosa, Gonyostomum semen, Skeletonema potamos, Chlamydomonas klinobasis, Pedospumella sp., and Neochlorosarcina negevensis were significantly correlated to TLI, while Limnoithona tetraspina, Theileria sp., and Pseudophyllomitus vesiculosus were significantly correlated to the water quality index (WQI). However, our random forest regression analysis using the top 100 species was unable to accurately predict the WQI and TLI.DiscussionThese results provide valuable data for evaluating the impact of APPs on PEC and for protecting water resource in the Chaohu Lake Basin.

The uses and applications of nanoparticles in our daily lives and on an industrial scale are rapidly expanding as a result of scientific and technological advancements. The production and application of nanoparticles are the subjects of nanotechnology. The worldwide use of nanoparticles is increasing daily because of their potential use and applications in antibacterial, antifungal, anti-inflammatory, and wound healing properties. ZnO nanoparticles (ZnO-NPs) are very popular as a source in plastics, ceramics, glass, rubber paints, and food due to their high UV light absorption and reflective characteristics. Nonetheless, the high-water solubility of ZnO-NPs increases their toxicity in aquatic habitats. Concerns about ZnO-NPs are not restricted to the possible negative impact they could have on specific ecosystems, notably aquatic ones. These concerns also include the influence on the health of the species that live in these ecosystems, which has a knock-on effect that affects human health. For these reasons, this review article aims to carefully document the toxicity related to the occurrence of ZnO-NPs in water, which reflects on fish and fish-food organisms.

Several types of contaminants are anthropogenically introduced into natural aquatic ecosystems and interact with other chemicals and/or with living organisms. Although metal toxicity alone has been relatively well studied, the toxic metal ion effects in the mixture have been thoroughly studied only during the last decades. This review focuses on the published reciprocal effects of different metals on different species of algae, together with describing their toxic effects on studied parameters. Phytoplankton as a bioindicator can help to estimate the reciprocal metal risk factor. Many methodologies have been developed and explored, such as the biotic ligand model (BLM), concentration addition (CA), independent action (IA), sensitivity distribution of EC50 species sensitivity distribution (SSD curves), and others, to study reciprocal metal toxicity and provide promising results, which are briefly mentioned too. From our review, we can commonly conclude the following: Zn acted antagonistically with most heavy metals (Al, Cu, Cd, and Ni). The Cu interaction with Cd, Fe, and Pb was mostly antagonistic. Cd showed synergistic behaviour with Hg, Cu, Zn, and Pb and antagonistic behaviour with Co and Fe in many cases. Methods and techniques need to be developed and optimised to determine reciprocal metal toxicity so that the ecotoxicological predictions made by using phytoplankton can be more accurate and related to real-time toxic metals risks to the aquatic ecosystem. This is the main objective of ecotoxicological tests for risk assessment. Understanding how metals enter algal cells and organelles can help to solve this challenge and was one of the main parts of the review.

Abstract Microplastics are a very complex, diverse, and persistent contaminant class in aquatic ecosystems, providing significant challenges for scientists in developing analytical methodologies, fate and transport models, identification of exposure routes, and toxicological risk evaluation are all key difficulties for scientists. Despite a considerable and developing body of thought concerning the effects of microplastics on aquatic species, nothing is known about the effects of microplastics on humans. Microplastics have been found in food all across the world. As a result, human exposure to microplastics through tainted food is unavoidable, possibly creating health risks. In recent years, a major research effort has added to our understanding, but there is an urgent need to simplify and integrate the findings. This review focuses on the effects of microplastics as well as methods for decomposing plastics without creating microplastic particles. Among the various plastic breakdown methods, employing microorganisms and nanotechnology might be a long-term solution in preventing environmental microplastic contamination.

Microplastic pollution (MPs) emerged as a significant environmental concern due to its persistent nature. These MPs particles endure in waters, soils, and even the atmosphere, posing potential threats to the entire ecosystem. Aquatic organisms are at risk of ingesting MPs, leading to accumulation in tissues, ultimately affecting entire food chain. This study aims to provide an overview of sources of MPs, distribution, and potential environmental impacts. MPs have been documented in various substances such as bottled water, salts, seafood, and even the air. However, the full extent of the health consequences on human exposure remains uncertain. Therefore, it is imperative that we draw public attention to the presence of these pollutants in the environment. To mitigate adverse effects of MPs, reducing plastic consumption, implementing improved waste management practices, and advocating sustainable behaviors are essential for well-being of natural ecosystems and the health human populations.

Lake Taihu, a subtropical shallow lake in the Yangtze River Basin, is the third-largest freshwater lake in China. It serves not only as a crucial source of drinking water and an ecological resource but also holds significant economic, tourism, and fisheries value. Phytoplankton, a vital component of aquatic ecosystems, plays a critical role in nutrient cycling and maintaining water structure. Its community composition and concentration reflect changes in the aquatic environment, making it an important biological indicator for monitoring ecological conditions. Understanding the impact of water quality on phytoplankton is essential for maintaining ecological balance and ensuring the sustainable use of water resources. This paper focuses on Lake Taihu, with water samples collected in February, May, August, and November from 2011 to 2019. Using quantile regression, a robust statistical analysis tool, the study investigates the heterogeneous effects of water quality on phytoplankton and seasonal variations. The results indicate significant seasonal differences in water quality in Lake Taihu, which substantially influence phytoplankton, showing weakly alkaline characteristics. When phytoplankton concentrations are low, pondus hydrogenii (pH), chemical oxygen demand (COD), total phosphorus (TP), total nitrogen (TN), water temperature (WT), and conductivity significantly affect them. At medium concentrations, COD, TP, TN, and WT have significant effects. At high concentrations, transparency and dissolved oxygen (DO) significantly impact phytoplankton, while TP no longer has a significant effect. These findings provide valuable insights for policymakers and environmental managers, supporting the prevention and control of harmful algal blooms in Lake Taihu and similar aquatic systems.

The primary data of micro- and macroplastics in the aquatic environment of Lake Markakol, located in the mountainous area of East Kazakhstan, are presented. The determination of micro- and macroplastics in water is based on sieving, drying, liquid oxidation, density separation and visual sorting using a microscope with a magnification of 40×. The detected plastic fragments in the aquatic environment include fishing line nets, Styrofoam balls, plastic bags, plastic bottles, wrappers, food labels and packages and other types of plastic waste. The sizes of the plastic fragments were ˃25 mm, 1.0–5.0 mm and 0.315–1.0 mm. The concentration of plastic in Lake Markakol was 837.5 µg/m3 in the tributaries and 482.1 µg/m3 in the lake water. The detected plastic mainly corresponded to sieve mesh sizes of 1.0–5.0 mm and 0.315–1.0 mm. The main sources of plastic pollution are fishing, tourism and the lack of adequate infrastructure for household waste management. These data emphasize the importance of measures to regulate plastic waste management in order to preserve the Lake Markakol ecosystem and maintain human health.

The pervasive presence of microplastics within river ecosystems has a profound and often underestimated detrimental impact. These minuscule yet persistent particles have infiltrated diverse biological habitats, making their detrimental effects on aquatic life increasingly concerning worldwide. The ability of microplastics to accumulate within aquatic organisms further exacerbates this concern. Consequently, the monitoring of microplastic pollution in surface water environments has emerged as a crucial endeavour, offering invaluable insights into the extent of this ecological threat. This study delved into the contamination levels of microplastics within two bivalve species, Perna viridis and Villorita cyprinoides, along the Chandragiri River in Kerala and Karnataka, South-West India, spanning eight distinct locations. The investigation yielded a significant discovery, with a total of 667 microplastic particles extracted from 288 individuals. On average, each individual bivalve harboured approximately 2.31 ± 0.93 microplastic items. Notably, these microplastic particles exhibited a wide range of morphological characteristics, underscoring their diverse origins and pathways into the ecosystem. Furthermore, five polymer types of microplastics were unequivocally confirmed through FTIR-ATR analysis, shedding light on the types of plastics that pose a threat to the riverine ecosystem. The findings of this study contribute to a growing body of evidence highlighting the global threat of microplastic pollution, urging international collaboration and innovative solutions to prevent further contamination and remediate existing microplastic burdens in aquatic environments. Highlights: • Microplastic contamination is a major concern in river ecosystems. • Microplastic in two bivalve species were characterized at Chandragiri River India. • The microplastics had diverse shapes and were composed of five different polymers. • This study emphasizes the need to tackle river microplastic pollution. [ABSTRACT FROM AUTHOR]

Mathematical modelling of the evolution of the size-spectrum dynamics in aquatic ecosystems was discovered to be a powerful tool to have a deeper insight into impacts of human- and environmental driven changes on the marine ecosystem. In this article we propose to investigate such dynamics by formulating and investigating a suitable model. The underlying process for these dynamics is given by predation events, causing both growth and death of individuals, while keeping the total biomass within the ecosystem constant. The main governing equation investigated is deterministic and non-local of quadratic type, coming from binary interactions. Predation is assumed to strongly depend on the ratio between a predator and its prey, which is distributed around a preferred feeding preference value. Existence of solutions is shown in dependence of the choice of the feeding preference function as well as the choice of the search exponent, a constant influencing the average volume in water an individual has to search until it finds prey. The equation admits a trivial steady state representing a died out ecosystem, as well as—depending on the parameter-regime—steady states with gaps in the size spectrum, giving evidence to the well known cascade effect. The question of stability of these equilibria is considered, showing convergence to the trivial steady state in a certain range of parameters. These analytical observations are underlined by numerical simulations, with additionally exhibiting convergence to the non-trivial equilibrium for specific ranges of parameters. [ABSTRACT FROM AUTHOR]

The increasing use of polypropylene (PP) in consumer products leads to the microplastic (PP MPs) contamination of the aquatic ecosystems. Comprehensive toxicological studies of weathered/aged and new PP MPs with Artemia salina are a need of the hour. Our study explores the toxicological differences between naturally weathered (aged) and prepared new PP MPs on Artemia salina. Both the weathered and new PP MPs were prepared using controlled grinding and sieving at ≤ 125 µm. Artemia salina was treated with different concentrations (0.25, 0.5, and 1 mg/mL) of PP MP particles for up to 48 h. The uptake of weathered PP MP particles by Artemia salina was higher than the new PP MPs. The accumulation of PP MP particles was found in the intestine. There was increased oxidative stress recorded in the animal treated with the weathered PP MPs than the new PP MPs. Artemia salina treated with weathered PP MPs showed higher ROS generation and increased, activity of oxidative enzymes like LPO, SOD, and CAT. Collectively, our findings underscore the detrimental effects of weathered and prepared new PP MPs on Artemia salina, which is an ecologically significant species of zooplankton. There is an urgent need and effective measures required to address plastic disposal strategies in an environmentally safe manner. [ABSTRACT FROM AUTHOR]

Anthropogenic disturbances, including non-indigenous species (NIS) and climate change, have considerably affected ecosystems and socio-economies globally. Despite the widely acknowledged individual roles of NIS and global warming in biodiversity change, predicting the connection between the two still remains a fundamental challenge and requires urgent attention due to a timely importance for proper conservation management. To improve our understanding of the interaction between climate change and NIS on biological communities, we conducted laboratory experiments to test the temperature and pCO2 tolerance of four gammarid species: two native Baltic Sea species (Gammarus locusta and G. salinus), one Ponto‐Caspian NIS (Pontogammarus maeoticus) and one North American NIS (Gammarus tigrinus). Our results demonstrated that an increase in pCO2 level was not a significant driver of mortality, neither by itself nor in combination with increased temperature, for any of the tested species. However, temperature was significant, and differentially affected the tested species. The most sensitive was the native G. locusta which experienced 100% mortality at 24 °C. The second native species, G. salinus, performed better than G. locusta, but was still significantly more sensitive to temperature increase than either of the NIS. In contrast, NIS performed better than native species with warming, whereby particularly the Ponto-Caspian P. maeoticus did not demonstrate any difference in its performance between the temperature treatments. With the predicted environmental changes in the Baltic Sea, we may expect shifts in distributions of native taxa towards colder areas, while their niches might be filled by NIS, particularly those from the Ponto-Caspian region. Although, northern colder areas may be constrained by lower salinity. Additional studies are needed to confirm our findings across other NIS, habitats and regions to make more general inferences. [ABSTRACT FROM AUTHOR]

Simple Summary: Bisphenol AF (BPAF) is a common environmental endocrine-disrupting chemical (EDC) that can potentially affect the growth and development of aquatic organisms. EDCs in the aqueous environment can be deposited in estuaries through runoff or diffused into the marine environment. The toxicity of the EDCs is related to exposure dose and duration. In this study, we used marine medaka as the experimental subject to dynamically observe the response of fish in terms of growth, reproduction and antioxidant immune system during BPAF exposure, providing new insights into understanding the marine ecological risk of BPAF. In recent years, bisphenol AF (BPAF) in aquatic environments has drawn attention to its ecological risks. This study aims to investigate the toxic effects of BPAF (188.33 μg/L) exposure for 30 days on female marine medaka (Oryzias melastigma). On the 10th and 30th day of exposure, the toxicity was evaluated using histological analysis of the liver and ovaries and the transcription levels of genes related to the antioxidant system, immune system, and hypothalamic-pituitary-gonadal (HPG) axis. Findings revealed that (1) BPAF exposure caused vacuolation, karyopyknosis and karyolysis in the liver of marine medaka, and the toxic impact augmented with duration; (2) exposure to BPAF for 10 days facilitated the growth and maturation of primary ova, and this exposure had a comparatively inhibitory effect after 30 days; (3) exposure to BPAF resulted in a biphasic regulation of the transcriptional abundance of genes involved in antioxidant and inflammatory response (e.g., il-8, cat), with an initial up-regulation followed by down-regulation. Additionally, it disrupted the transcriptional pattern of HPG axis-related genes (e.g., 3βhsd, arα). In conclusion, 188.33 μg/L BPAF can alter the expression levels of functionally related genes, impair the structural integrity of marine organisms, and pose a threat to their overall health. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic reshaped the global response to a pandemic, including the way of using chemical compounds such as disinfectants and antibiotics. The large-scale use of antibiotics and disinfectants during the COVID-19 pandemic caused environmental pressure not only due to the chemicals themselves but also due to their effect on bacterial communities, inducing resistance to chemicals and changing the population structure of bacterial communities, especially in aquatic environments. The dissemination of fecal bacteria, including antibiotic-resistant bacteria, and pathogens from hospital wastewater into the environment, via wastewater treatment plants (WWTPs), triggered the premises of a major public health issue. Rivers flowing through cities are natural streams for WWTP discharges, and they directly bear the impact of anthropic activities, disseminating domestic and industrial pollution over large areas. The aim of the present study was to assess the microbiological bacterial structure of municipal and hospital wastewaters as well as their impact on natural streams, covering the pre-to post-COVID-19 pandemic period of time. The results indicated that the COVID-19 pandemic had a direct impact on hospital wastewater microbiological quality and the environment due to an excessive use of antibiotics and disinfectants. In addition, the constant presence of antibacterial compounds increased the rate of bacterial selection and induced population structural changes in the bacterial communities from aquatic systems. [ABSTRACT FROM AUTHOR]

Microplastics can be ingested by a wide range of aquatic animals. Extensive studies have demonstrated that microplastic ingestion—albeit often not lethal—can affect a range of species life‐history traits. However, it remains unclear how the sublethal effects of microplastics on individual levels scale up to influence ecosystem‐level dynamics through cascading trophic interactions.Here we employ a well‐studied, empirically fed three‐species trophic chain model, which was parameterized to mimic a common type of aquatic ecosystems to examine how microplastic ingestion by fish on an intermediate trophic level can produce cascading effects on the species at both upper and lower trophic levels.We show that gradually increasing microplastics in the ingested substances of planktivorous fish may cause population structure effects such as skewed size distributions (i.e. reduced average body length vs. increased maximal body size), and induce abrupt declines in fish biomass and reproduction.Our model analysis demonstrates that these abrupt changes correspond to an ecosystem‐level tipping point, crossing which difficult‐to‐reverse ecosystem degradation can happen. Importantly, microplastic pollution may interact with other anthropogenic stressors to reduce safe operating space of aquatic ecosystems.Our work contributes to better understanding complex effects of microplastic pollution and anticipating tipping points of aquatic ecosystems in a changing world. It also calls attention to an emerging threat that novel microplastic contaminants may lead to unexpected and abrupt degradation of aquatic ecosystems, and invites systematic studies on the ecosystem‐level consequences of microplastic exposure. [ABSTRACT FROM AUTHOR]

This review summarises the wide range of toxicological effects of cadmium on various fish species and certain mammals. Large amount of cadmium is released into the aquatic environment through different anthropogenic activities and threatens the aquatic life. Therefore, study of toxic effects of cadmium in fish and its possible effects in human is very important. Several studies has shown accumulation and distribution of cadmium in fish tissue, damages tissue structure and function and causes several adverse effects on cardiovascular system, immune system, nervous system and reproductive regulatory system. Histopathological effects of cadmium include multi-organ tissue injury. Significant alterations occur in biochemical and haematological parameters of blood in cadmium exposed fish. Residues of cadmium have been reported from gill, liver, kidney, muscle and other tissues. Therefore, the toxic effects of cadmium on fish occur with multiple tissue system. In mammals, cadmium act as a multi-organ toxin. It also effects the DNA replication and repair at cellular level. [ABSTRACT FROM AUTHOR]

Fish biodiversity, a significant part of the aquatic ecosystem, has been studied widely in India. However, the distribution and diversity of fish species have not been well-researched at the state and/or regional levels. Karnataka is bestowed with 8% of the country's water resources, which are under extreme pressure because of unregulated population growth, biological invasion, and developmental requirements. Since the middle of the nineteenth century, India has been introducing alien species to its water bodies. Currently, 13.6% of the fish diversity in India is exotic and has been established voluntarily or involuntarily for various purposes. The establishment of invasive alien fishes negatively influences native fish communities around the globe. In general, most publications present the latest status of ichthyofauna in several regions of Karnataka; however, there is no up-to-date documentation on strategic environmental developments and unforeseen challenges, such as invasive alien species (IAS). This study reconstructs existing knowledge while analytically reviewing challenges, potential management techniques, advancements, and the impacts of climate change and disseminates the data necessary for the comprehension of the biological invasion of IAS. [ABSTRACT FROM AUTHOR]

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The coronavirus disease (COVID-19) pandemic has amplified the presence of single-use plastic pollutants in the ocean. Africa, for instance, used personal protective equipment (PPE) that is disposed of indiscriminately into the environment, which is usually washed into the ocean. This pollutes the ocean and consequently lowers fishery yields. Aside from improper disposal practices, single-use personal protective equipment's accumulation in the aquatic environment is caused by the absence or inadequate recycling and the lack of alternative uses for these wastes. It is estimated that globally, about 129 billion facemasks and 65 billion gloves are used each month contributing to widespread environmental pollution. This study analyzed and discussed the effects of plastic waste on the biodiversity of aquatic environments (ocean) vis a vis the management of personal protective equipments across the globe. Results from the review conducted showed that single-use personal protective equipments have the potential to release harmful chemicals, toxic substances, pathogenic microorganisms, and heavy metals into the environment and thus can hurt biodiversity and seafood security. To limit the identified negative effects, there is a need to regulate the use of single-use personal protective equipments and also promote the use of reusable masks. Educating and empowering especially coastal communities to act collectively to minimize plastic pollution (PPE) is a recommended measure for the protection of ocean resources. [ABSTRACT FROM AUTHOR]

The study was designed to assess the water quality based on physico-chemical parameters and phytoplankton communities of eight lentic water bodies of Haryana which are famous for mass bathing and religious rituals taking place here. To evaluate comparative analysis of composition, diversity and distribution of Phytoplankton and physico-chemical factors, water samples were collected seasonally viz., summer, monsoon, post monsoon and in winters from all the eight sites in triplicate. Total 118 phytoplankton taxa were observed at all sites. Among these cyanophyceae group was found most dominant at sites 1, 2, 4, 5, 7, 8 whereas cholorophyceae at site 6, bacillariophyceae at site 1,3,4,7 whereas xanthophyceae was in abundance at site 5. Population density (nos. L-1) wise phytoplankton trend was Cyanophyceae > Chlorophyceae > Bacillariophyceae >Desmidiaceae and Species diversity wise phytoplankton trend observed was Chlorophyceae > Bacillariophyceae > Cyanophyceae >Desmidiaceae. Correlation of different phytoplankton groups with physicochemical factors revealed a significant negative correlation of Cyanophyceae with pH, whereas a significant positive correlation of ortho-phosphate with Desmids and bacillariophyceae wheareas CO2 showed a positive correlation with Xanthophyceae. Appearance of pollution tolerant taxa of phytoplankton Microcystis aeruginosa, Phormidium sp., Scenedesmus spp., Pediastrum spp., Mougeotia sp., Synedra sp., Pediastrum spp. at most of the sites indicated the sign of the more organic pollution and degradation in the water quality of the selected sites due to religious immersion, mass bathing and by other anthropogenic activities. Suitable remedial actions should be adopted by regulatory bodies and policy makers to maintain the water quality of these aquatic systems. [ABSTRACT FROM AUTHOR]

Excessive consumption of cleaning and disinfecting agents, which constitute a distinct group of emergent pollutants known as PPCPs ("Pharmaceutical and Personal Care Products"), results in their accumulation in aquatic environments. Conventional wastewater treatment plants are unable to effectively remove the emergent pollutants that are present, including personal care product residues. This article focuses on the determination of surfactant substances in model samples prepared from selected personal care products and their biodegradability under laboratory-created aquatic ecosystem conditions. The conducted biodegradation processes, based on the monitored indicator (surfactants) in the model samples, confirm that the utilization of aquatic vegetation and gravel substrates can efficiently eliminate the present contaminants. Insights gained from researching the biodegradability of PPCP group products are applicable, including experiences with plant compositions used in aquatic environments, particularly in the construction of root-zone wastewater treatment systems. [ABSTRACT FROM AUTHOR]

The paper presents an overview of the results of multiannual investigations of the dynamics of migration of several metals in the ecosystems of the Dniester and Prut rivers – the main water courses of the Republic of Moldova. The dynamics of metals in water, suspensions, silts, aquatic plants, planktonic and benthic invertebrates, fish at different stages of development (eggs-larvae, fry, mature fish) was investigated depending on abiotic factors and under the influence of human activity. The fragmentation of the Dniester River, through the construction of several dams, and the operation of the Dniester Hydropower Complex have reduced the processes of sedimentation and self-cleaning in the river, which has reflected on the migration and circuit of metals, causing an imbalance of the native processes of metal migration, characteristic for the river ecosystems of the studied region. The impact of metals on the processes of formation of primary production and destruction of organic matter in aquatic ecosystems and on the development of fish, especially at the early stages of ontogenesis, was identified. The level of accumulation of metals in aquatic plants, planktonic, benthic invertebrates and fish is a reflection of the metal content in the aquatic environment, but also depends on the biological properties of the hydrobionts, and the overall ecological status of the aquatic ecosystem. Synergistic, additive and antagonistic interactions between different metals have been recorded. The identified regularities of the migration and accumulation of metals in the “water-solid suspensions-silts-hydrobionts” system can be used in monitoring and evaluating the functioning of aquatic ecosystems. [ABSTRACT FROM AUTHOR]

Carbonic anhydrase (CA) is one of the most vital enzymes in living cells. This study has been performed due to the significance of this metalloenzyme for life and the novelty of some CA families like ζ‐CA to evaluate evolutionary processes and quality check their sequences. In this study, bioinformatics methods revealed the presence of ζ‐CA in some eukaryotic and prokaryotic microorganisms. Notably, it has not been previously reported in prokaryotes. The coexistence of β‐ and ζ‐CAs in some microorganisms is also a novel finding as well. Also, our analysis identified several CA proteins with 6–14 amino acid intervals between histidine and cysteine in the second highly conserved motif, which can be classified as the novel ζ‐CA subfamily members that emerged under the Zn deficiency of aquatic ecosystems and selection pressure in these environments. There is also a possibility that the achieved results are rooted in the contamination of samples from the environmental microbiome genome with genomes of diatom species and the occurrence of errors was observed in the DNA sequencing outcomes. Combining of all results from evolutionary analysis to quality control of ζ‐CA DNA sequences is the incentive motivation to explore more the hidden aspects of ζ‐CAs. [ABSTRACT FROM AUTHOR]

Hydrological drought has wide‐ranging impacts on water quality, nutrient and carbon metrics, and given the uncertainty of climate change and the predicted increased frequency and intensity of drought in the future, investigations into changes induced by drought become increasingly important. This study compared physicochemical parameters (temperature, conductivity, pH and DO), nutrients (TN, NOX [NO2 + NO3], NH3 and TP) and carbon (TOC and DOC) between hydrological drought conditions (2006–2008) and hydrological normal conditions (2016–2019) at five sites along the lower Savannah River (Georgia, USA). Although we had predicted that water temperatures would increase from drought, we instead found temperature was significantly lower during drought conditions. Levels of pH and DO were significantly higher during drought. Further, TN, TOC and DOC concentrations were significantly lower during drought, but NOX concentrations were significantly higher during drought. Conductivity varied at the lower river sites, being significantly higher during drought at sites located below the city of Augusta, GA. These complex changes could be attributed to volume reductions coupled with an increase in the percentage of total flow originating from groundwater as well as limnetic reservoir inputs, persistent point source pollution, reduced natural catchment inputs and/or reduced floodplain interactions. The changes that occurred during drought may be disruptive to aquatic life, not only from reduced water quantity but also due to a scarcity of some biologically essential materials and lower food resources, combined with artificially high levels of some other potentially stressful materials. [ABSTRACT FROM AUTHOR]

This article provides information on the identification of micromycetes found in samples taken from areas of transboundary rivers of Azerbaijan with different levels of anthropogenic impact, and the study of their role in the removal of pollutants. Certain micromycetes were used as indicators of water quality. As a result of the studies, micromycetes belonging to 38 species from 16 genera were identified. Directly at the sampling site, water temperature, pH, and the amount of dissolved oxygen in the water were measured, and biogenic elements were determined in laboratory conditions. The presence of nutrients in the studied river waters showed variable results. Thus, in the Astarachay River, nitrites range from 0.01–0.02 mg/l, nitrates 0.56–0.70 mg/l, ammonium 0.5–1.50 mg/l, phosphates 0.00–0.01 mg/l. In the Bolgarchay River, these indicators for nitrite range from 0.02– 0.05 mg/l, for nitrates 0.20–0.50 mg/l, for ammonium 0.10– 0.44 mg/l, for phosphates 0.01–0.05 mg/l. In the Arazchay River, nitrites range from 0.01–0.83 mg/l, nitrates 0.08– 7.40 mg/l, ammonium 0.05–3.57 mg/l, phosphates 0.05– 0.94 mg/l, and in Okhchuchay these indicators for nitrite range from 0.09 to 0.71 mg/l, nitrates 0.68–6.00 mg/l, ammonium 0.23–6.45 mg/l, phosphates 0.09–0.65 mg/l. The results obtained showed that the identified microscopic fungi are involved in the formation of rich flora as an adaptation in river waters. The biomass and number of micromycetes significantly depend on hydrochemical conditions: parameters such as temperature, dissolved oxygen, pH, forms of nitrogen, phosphorus and organic carbon fractions. It can be recommended to use mushrooms for biological control of surface water purity and sanitary safety. It should be noted that environmental factors also influence the diversity of micromycetes [ABSTRACT FROM AUTHOR]

Abstract: Aim The freshwater environment is indeed diverse and complex, and it faces numerous challenges due to human activities. One approach to evaluating these human interventions is through the use of bioindicators, with fish being one of the key groups studied in the aquatic environment. However, the existent studies report that only a limited number of Brazilian ichthyofauna species have been investigated as potential bioindicators. Methods The data present here were organized through a bibliographic review that adopts an exploratory and descriptive approach, focusing on articles published between the years 2000 and 2022, utilizing terms such as “bioindicators,” “Brazilian fish,” and “aquatic ecosystem” in both Portuguese and English languages. Results Despite Brazil having the most diverse ichthyofauna on the planet, the research has focused on only 45 species thus far. Among these, Rhamdia quelen (Quoy & Gaimard, 1824) emerged as the most frequently studied species. The analysis of gill and liver tissues was found to be the most common method employed in these studies, while other tissues received relatively little attention. Moreover, the distribution of studies on bioindicator species was uneven, with the Upper Paraná ecoregion having the highest number of species investigated. This suggests that research efforts in this field have not been uniformly distributed across Brazil. Conclusions The patchy nature of studies on bioindicators of the Brazilian ichthyofauna highlights the need for greater incentives and support for research in this area. With Brazil's exceptional ichthyofauna diversity, there is ample potential to identify and utilize additional species as environmental indicators. By expanding the scope of studies and addressing the geographical imbalance, a more comprehensive understanding of the impacts of human activities on freshwater ecosystems in Brazil can be achieved. This knowledge is vital for effective conservation and management efforts to protect and sustain the country's valuable aquatic resources.

The global expansion of aquaculture has driven significant technological advancements, including raceways, Integrated Multitrophic Aquaculture (IMTA) and marine offshore cages. However, unregulated aquaculture escapees pose a severe threat to aquatic biodiversity, acting as a potential time bomb for the entire ecosystem. Addressing this issue requires a comprehensive understanding of the impact of unintentional escapees on aquatic ecosystems, particularly in India and riparian East African countries (Kenya, Uganda, and Tanzania). Using an exploratory research design drawing from various peer-reviewed sources, this study outlines the dynamic growth of aquaculture in these countries, identifies high-impact escape incidents, and correlates risks and remedies with global cases, especially in regions such as Norway, Scotland, Ireland, Colombia, and the United States, where serious incidents of aquaculture escapees have been reported. The research categorizes aquaculture development trends, discusses mechanisms of escapee impact, proposes remedies, assesses methods and inferential strength, and highlights gaps in the existing literature. The study revealed complex ecological shifts caused by aquaculture escapees from invasive non-native fish species, affecting predation, competition, and genetic diversity. Escaped fish from aquaculture facilities pose a significant threat to aquatic biodiversity, especially in the study regions. The escalating risk of unintentional escapes was highlighted in India and three East African countries. To mitigate this, the study proposes integrating escapee management into national fisheries systems, amending fisheries laws, holding fish farmers accountable for aquaculture system failure, and developing comprehensive regulations for non-native species in aquaculture within the study regions. It is recommended to standardize the planning for aquaculture facilities and implement emergency plans, training, local mobilization and further research on the impact thresholds of aquaculture escapees in the study regions. Ecological education in aquaculture communities and the recognition of the role of translational scientists are crucial for the dissemination of knowledge. Urgent government action is needed to address unreported aquaculture escapes, preventing further ecosystem degradation and ensuring global aquaculture sustainability.

Abstract Microplastics are widespread pollutants, but few studies have linked field prevalence in organisms to laboratory uptakes. Aquatic filter feeders may be particularly susceptible to microplastic uptake, with the potential for trophic transfer to higher levels, including humans. Here, we surveyed microplastics from a model freshwater shrimp, common caraidina (Caridina nilotica) inhabiting the Crocodile River in South Africa to better understand microplastic uptake rates per individual. We then use functional response analysis (feeding rate as a function of resource density) to quantify uptake rates by shrimps in the laboratory. We found that microplastics were widespread in C. nilotica, with no significant differences in microplastic abundances among sampled sites under varying land uses, with an average abundance of 6.2 particles per individual. The vast majority of microplastics found was fibres (86.1%). Shrimp microplastic accumulation patterns were slightly higher in the laboratory than the field, where shrimp exhibited a hyperbolic Type II functional response model under varying exposure concentrations. Maximum feeding rates of 20 particles were found over a 6 h feeding period, and uptake evidenced at even the lowest laboratory concentrations (~10 particles per mL). These results highlight that microplastic uptake is widespread in field populations and partly density dependent, with field concentrations corroborating uptake rates recorded in the laboratory. Further research is required to elucidate trophic transfer from these taxa and to understand potential physiological impacts.

Bacteria are vital for maintaining ecosystem function in the rapidly changing environment, but limited data was reported regarding the characteristics of bacterial communities along the regional-scale in aquatic ecosystems on the Fildes Peninsula (Antarctica), where vulnerable aquatic habitats have been affected by the dramatic retreat of the Collins glacier. This study revealed differences and hidden connections of bacterial communities in two aquatic ecosystems (periglacial lakes and coves) near Collins glacier using amplicon sequencing. The results showed periglacial lakes and coves harbored 568 and 388 unique OTUs, respectively, but also shared 199 common OTUs, which meant there existed some linkages connections between the two ecosystems. Compared to periglacial lakes, communities in coves exhibited decreased richness and Shannon index (P

The Caspian Sea is important in terms of environment and monitoring of biological pollutants due to its long coastlines and commercial activities of the industrial port of agriculture and tourism. Identifying marine environmental pollutants is the first step to rebuilding and protecting this valuable ecosystem. The purpose of this study was to determine the amount of Polychlorinated biphenyls in sediments and Barnacles of Anzali and Caspian ports in Guilan province, Iran. Therefore, Barnacle and sediment samples were collected in 2 stations whit 3 replications in Anzali and Caspian ports by VanVeen Grab sampler in summer according to the life cycle of Barnacles. After preparation and drying with freeze dryer, after analysis, it was read by gas chromatography. The highest concentration of PCBs in Barnacles in Anzali station was related to isomers PCB-81 & PCB-77 and the lowest was related to isomers PCB-114 and PCB-156. The highest concentration of PCBs in Barnacles in Caspian station was related to isomers PCB-28 and PCB-77 and the lowest was related to isomers PCB-114 & PCB-153. The highest PCB concentration in sediment in Anzali and Caspian ports was recorded similarly for isomers PCB-52 & PCB-28 and the lowest was related to isomers PCB-114 and PCB-156.

Streams constitute the water supply of the watersheds and provide the transfer of energy along the course of water, ensuring water biodiversity. Due to the different uses of the earth, the benthic community is being suppressed. The objective of this study is to investigate the effects of changes in land use on the abundance, richness, and diversity of benthic macroinvertebrates in subtropical streams, considering the physical and chemical variables of streams seasonally. In total, 144 samples were collected between February 2022 and November 2023 at 12 sites distributed in a watershed in southern Brazil, four sites for each land use. Herein, 83.520 individuals were identified, comprising 67 taxa. There was a decrease in richness along the forested–rural–urban gradient and a greater abundance in the urban environment, without the significant influence of seasonality. We conclude that the diversity of benthic macroinvertebrate in the streams is influenced not only by environmental variables but also by the spatial distribution between streams. The proximity of the streams generates a similarity in dominance. This study contributed to understanding the relationships of the environment with the benthic community and considering the spatial distribution among the streams sampled in future investigations.

Phosphorus (P) is a crucial nutrient in lake ecosystems and organic phosphorus (Po) is a significant component. However, the distribution characteristics and migration behaviour of Po in ice–water–sediment systems under freezing and thawing conditions in cold and arid regions remain unclear. This study aims to investigate the forms of Po and its contribution to endogenous P pollution. We selected three lakes (Dai, Hu, and Wu Lake) and employed phosphorus nuclear magnetic resonance (31P-NMR) techniques to analyse the following: (1) The total phosphorus (TP) content, which was the highest in the water from Dai Lake (0.16 mg/L), with substantial seasonal variation observed in Wu Lake, where P content was four times higher in summer than in winter because of farmland drainage. (2) Eutrophication analysis, which indicated that Dai Lake had significantly higher eutrophication levels than Wu Lake, with P being the controlling factor in Dai Lake and both N and P in Wu Lake. The proportion of Po in the TP content was 90%, 70%, and 55% for Wu, Dai, and Hu Lake, respectively, indicating that Po was the main component of eutrophic lakes. (3) 31P-NMR, which revealed that orthophosphate (Ortho-P) and monoester phosphate (Mon-P) were the main P components in the winter, with a higher P content in Dai Lake. Ortho-P has a higher content in ice, indicating that inorganic phosphorus (Pi) migration is the main factor in ice–water media. Mon-P showed multiple peaks in Dai Lake, indicating a complex composition of adenosine monophosphate and glucose-1-phosphate. (4) The ice–water phase change simulation experiments, which showed that phosphate was the least repelled in ice, while pyrophosphate (Pyro-P) and macromolecular P were more repelled. Adding sediment enhanced the migration of P but did not change the repulsion of macromolecular P, suggesting the molecular structure as the main influencing factor. These results provide important scientific evidence for the quantitative analysis of Po pollution in lake water environments, aiding in P load reduction and risk prevention and control.

[Objective] The value change and radiation effect of the regional aquatic ecosystem service function were analyzed in order to provide a scientific basis for sustainable development of regional water resources and ecological compensation of a river basin. [Methods] ArcGIS software was used to extract land use data for Luoyang City, Henan Province from 2000 to 2020 in order to obtain the area of water type. The emergy method was used to quantify and analyze the changes of aquatic ecosystem service functions, and the functional radiation was analyzed by the break point model. [Results] From 2000 to 2020 (in five-year time steps), the total emergy values of aquatic ecosystem services at Luoyang City were 8.01×1021 sej， 1.29×1022 sej， 1.27×1022 sej， 1.29×1022 sej， and 1.31×1022 sej, respectively, with a general increasing trend. Among these emergy values, the focus of service composition had shifted from supply function to cultural function. In this system, biodiversity protection, aquatic product production, water resource supply, water resource regulation, and leisure and entertainment functions were dominant. Leisure and entertainment functions have become core functions. In addition, the main transfer areas of the aquatic ecosystem service function in Luoyang City were Songxian County and Luoning County, with total outward transfer values of 3.10×1020 sej and 3.21×1020 sej, respectively. The main transfer areas were Luanchuan County, Yiyang County, Yichuan County, and Ruyang County. [Conclusion] Greater attention will need to be given to ecological protection of water, increasing support and guidance for regional tourism, and reasonably carrying out ecological compensation in areas similar to Luoyang City to promote the coordinated development of the economy, society, and ecology in various regions.