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The multifaceted threats to global freshwater ecosystems, especially in urban environments, impact hydrological cycles, flora and fauna, habitats and ecosystem processes. While these ecosystems can potentially offer important services to the urban populations by providing natural areas inside cities, the constraints imposed by urbanisation and a high population density may result in the loss of those benefits. Thus, it is important to adopt a quantitative approach to assess the value of urban freshwater ecosystem services in order to enable strategic urban planning that balances urban development with the protection of these ecosystems. We have therefore performed a systematic review of Scopus database publications from 2006 to 2022 that focused on provisioning, regulating and maintenance, as well as cultural services, provided by urban river ecosystems. The screening identified 118 papers, 43% of which focused on urban stream ecosystems (stream and/or riparian area). For provisioning services, indicators were related to water and food supply, while regulation indicators were linked to water quality and flood mitigation; cultural services were mainly related to physical interactions with the ecosystems, education and aesthetic experiences. The economic valuation of urban river ecosystem services is the subject of study in 19% of the identified articles, mainly in relation to potential river restoration. Finally, 18% of articles incorporated public opinions of stakeholders and citizens, underlining the significant role of their input in understanding and managing urban river ecosystems. More studies on urban streams are needed, and standardising indicators and promoting greater citizen involvement in the evaluation of ecosystem services are challenges that remain to be overcome. [ABSTRACT FROM AUTHOR]

The lack of reliable data on length-mass relationships, essential to obtain accurate biomass estimates, limits our ability to easily assess secondary production by aquatic invertebrates. In the absence of published equations from similar habitat conditions, authors often borrow equations developed in geographic regions with different climate conditions, which may bias biomass estimates. A literature overview of published size-mass relationships for Portugal and Sweden highlights the need for further data within these biogeographic regions. We increased the number of equations available to Southern and Northern Europe, developing 18 new length-mass relationships for two families and 10 genera in Portugal and Sweden. All equations were published for the first time for these countries, except the genus Asellus. Our length-mass relationships were obtained from specimens collected on a one-time sampling of eight ponds in Portugal and five ponds in Sweden during late spring in 2023. Dry mass (DM) was modelled as a function of body length (BL), using the natural log-linear function with a power model (ln DM = ln a + b × ln BL). The equations obtained were compared with linear mixed models testing the fixed effects of "body length" and "country", as well as their interaction. A comparison of the equations developed in this study showed country-specific differences for all taxa, expect the genus Caenis, indicating a low potential transferability of the equations between Southern and Northern Europe. In contrast, the comparison of the equation obtained for A. aquaticus in this study with an equation published for this taxon in Sweden showed great similarities, suggesting a high transferability. Recommending caution in the borrowing of published length-mass equations, that can differ drastically between different geographic and climatic regions, especially at larger sizes, we provide a series of guidelines and good practices in this field. [ABSTRACT FROM AUTHOR]

The lack of reliable data on length-mass relationships, essential to obtain accurate biomass estimates, limits our ability to easily assess secondary production by aquatic invertebrates. In the absence of published equations from similar habitat conditions, authors often borrow equations developed in geographic regions with different climate conditions, which may bias biomass estimates. A literature overview of published size-mass relationships for Portugal and Sweden highlights the need for further data within these biogeographic regions. We increased the number of equations available to Southern and Northern Europe, developing 18 new length-mass relationships for two families and 10 genera in Portugal and Sweden. All equations were published for the first time for these countries, except the genus Asellus. Our length-mass relationships were obtained from specimens collected on a one-time sampling of eight ponds in Portugal and five ponds in Sweden during late spring in 2023. Dry mass (DM) was modelled as a function of body length (BL), using the natural log-linear function with a power model (ln DM = ln a + b × ln BL). The equations obtained were compared with linear mixed models testing the fixed effects of “body length” and “country”, as well as their interaction. A comparison of the equations developed in this study showed country-specific differences for all taxa, expect the genus Caenis, indicating a low potential transferability of the equations between Southern and Northern Europe. In contrast, the comparison of the equation obtained for A. aquaticus in this study with an equation published for this taxon in Sweden showed great similarities, suggesting a high transferability. Recommending caution in the borrowing of published length-mass equations, that can differ drastically between different geographic and climatic regions, especially at larger sizes, we provide a series of guidelines and good practices in this field.

Based on our own material and literary data, a generalization of information on the genus Tobrilus Andrássy, 1959 has been carried out. The diagnosis of this genus has been changed, the species diagnostic characteristics have been analyzed, and the species structure of the genus has been examined. The genus includes 29 valid species. The key to the definition of the species of genus and the summary table of morphological characteristics of valid species are given. [ABSTRACT FROM AUTHOR]

Aims The purpose of this work was to study extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (ESBL-EC) in freshwaters, hospital effluents, and wastewaters during two sampling campaigns in 2021. Methods and results Water sampling was performed at 24 stations in the Ourthe watershed in Belgium. A total of 644 ESBL (n  = 642) and AmpC (n  = 2) E. coli strains were isolated. Disk-diffusion assays were performed following the EUCAST's recommendations. All strains were tested for the presence of bla CTX-M-1, bla CTX-M-2, and bla CTX-M-9 gene groups by PCR. Genes belonging to bla CTX-M-1 and bla CTX-M-9 groups were detected, respectively, in 73.6% and 14.9% of the strains. No bla CTX-M-2 group's gene was found. A subset of strains (n  = 40) was selected for whole genome sequencing. Escherichia coli serotype O18: H7 ST 1463 was predominant (n  = 14) in the sequenced strains and showed pathogenicity in the Galleria mellonella larvae model. β-lactamase genes identified were bla CTX-M (n  = 21), with bla CTX-M-15 mostly represented (n  = 15), as well as bla TEM (n  = 11), bla OXA (n  = 7), bla SHV (n  = 9), and carbapenemase (CP) genes were observed in several strains— bla KPC-3 (n  = 19), bla NDM-1 (n  = 1), bla VIM-1 (n  = 2), and bla OXA-244 (n  = 2)—even from freshwaters. Conclusions ESBL-EC are widely distributed in the aquatic environment in Belgium and contain a variety of ESBL and CP genes. [ABSTRACT FROM AUTHOR]

Abstract Ecosystem services (ES) are essential to sustainable development at multiple spatial scales. Monitoring ES potential (ESP) at the metropolitan level is imperative to sustainable cities. We developed a procedure for long-term monitoring of metropolitan ESP dynamics, utilizing open-source land use land cover (LULC) data and the expert matrix method. We compared the ESP results of 38 European Capital Metropolitan Areas (ECMA) regarding biodiversity integrity, drinking water provision, flood protection, air quality, water purification, and recreation & tourism. Our results show significant declines in ESP across ECMA due to LULC alteration between 2006, 2012, and 2018. We found that ECMA in post-socialist European countries like Poland (Warszawa) have experienced high rates of land use transformation with a remarkable impact on ESP. Surprisingly, we found that Fennoscandinan ECMA, like Helsinki, Stockholm, and Oslo which lead the cumulative ESP ranking, faced the ESP reduction of the highest impact in recent years. The correlation analysis of ESP dynamics to urban expansion and population growth rates suggests that inattentive urbanization processes impact ESP more than population growth. We unveil the implications of our results to the EU and global level agendas like the European Nature Conservation Law and the Sustainable Development Goals.

Abstract Background Aerobic anoxygenic phototrophic (AAP) bacteria are heterotrophic bacteria that supply their metabolism with light energy harvested by bacteriochlorophyll-a-containing reaction centers. Despite their substantial contribution to bacterial biomass, microbial food webs, and carbon cycle, their phenology in freshwater lakes remains unknown. Hence, we investigated seasonal variations of AAP abundance and community composition biweekly across 3 years in a temperate, meso-oligotrophic freshwater lake. Results AAP bacteria displayed a clear seasonal trend with a spring maximum following the bloom of phytoplankton and a secondary maximum in autumn. As the AAP bacteria represent a highly diverse assemblage of species, we followed their seasonal succession using the amplicon sequencing of the pufM marker gene. To enhance the accuracy of the taxonomic assignment, we developed new pufM primers that generate longer amplicons and compiled the currently largest database of pufM genes, comprising 3633 reference sequences spanning all phyla known to contain AAP species. With this novel resource, we demonstrated that the majority of the species appeared during specific phases of the seasonal cycle, with less than 2% of AAP species detected during the whole year. AAP community presented an indigenous freshwater nature characterized by high resilience and heterogenic adaptations to varying conditions of the freshwater environment. Conclusions Our findings highlight the substantial contribution of AAP bacteria to the carbon flow and ecological dynamics of lakes and unveil a recurrent and dynamic seasonal succession of the AAP community. By integrating this information with the indicator of primary production (Chlorophyll-a) and existing ecological models, we show that AAP bacteria play a pivotal role in the recycling of dissolved organic matter released during spring phytoplankton bloom. We suggest a potential role of AAP bacteria within the context of the PEG model and their consideration in further ecological models.

Freshwater ecosystems provide essential services for human well-being, with their conservation success reliant on the precise quantification of biodiversity. Diplostraca (= Cladocera) and Copepoda are diverse groups of microcrustaceans in aquatic ecosystems, important for a multitude of these services. We examined biodiversity trends of these groups, utilizing a comprehensive dataset, approximately 2341 studies, spanning from the early 19th Century to the present day, aiming at predicting the total number of microcrustacean species that will have been described by 2100. Descriptions increased until the 1900s, surged, and then declined after 1975. The predictive models indicate that by the year 2100, an additional 16–68% of cladoceran species and 37–126% of copepod species are likely to be identified, representing a significant portion of currently unrealised biodiversity. Eighteen prolific authors contributed to a quarter of these descriptions, with the rest spread among numerous authorities. Based on our extrapolation, the total number of microcrustacean species could potentially exceed 6114 by 2050 and 9046 by 2100, notwithstanding extinctions. These findings, which point to a significant amount of unrealised biodiversity, underscore the need to refine biodiversity estimates beyond conventional expert opinion. Such accuracy is crucial for addressing the underappreciated scale of the current biodiversity crisis. [ABSTRACT FROM AUTHOR]

The present study demonstrates the presence of the neurotoxin β-N-methylamino-L-alanine and its cyanobacterial producers in irrigation water and grains of some cereal plants from farmlands irrigated with Nile River water in Egypt. BMAA detected by LC–MS/MS in phytoplankton samples was found at higher concentrations of free form (0.84–11.4 μg L−1) than of protein-bound form (0.16–1.6 μg L−1), in association with the dominance of cyanobacteria in irrigation water canals. Dominant cyanobacterial species isolated from these irrigation waters including Aphanocapsa planctonica, Chroococcus minutus, Dolichospermum lemmermanni, Nostoc commune, and Oscillatoria tenuis were found to produce different concentrations of free (4.8–71.1 µg g−1 dry weight) and protein-bound (0.1–11.4 µg g−1 dry weight) BMAA. In the meantime, BMAA was also detected in a protein-bound form only in grains of corn (3.87–4.51 µg g−1 fresh weight) and sorghum (5.1–7.1 µg g−1 fresh weight) plants, but not in wheat grains. The amounts of BMAA accumulated in these grains correlated with BMAA concentrations detected in relevant irrigation water canals. The presence of BMAA in cereal grains would constitute a risk to human and animal health upon consumption of contaminated grains. The study, therefore, suggests continuous monitoring of BMAA and other cyanotoxins in irrigation waters and edible plants to protect the public against exposure to such potent toxins. [ABSTRACT FROM AUTHOR]

Background: Together with the intensification of dry seasons in Neotropical regions, increasing deforestation is expected to exacerbate species extinctions, something that could lead to dramatic shifts in multitrophic communities and ecosystem functions. Recent studies suggest that the effects of habitat loss are greater where precipitation has decreased. Yet, experimental studies of the pure and interactive effects of drought and deforestation at ecosystem level remain scarce. Methods: Here, we used rainshelters and transplantation from rainforest to open areas of natural microcosms (the aquatic ecosystem and microbial-faunal food web found within the rainwater-filled leaves of tank bromeliads) to emulate drought and deforestation in a full factorial experimental design. We analysed the pure and interactive effects of our treatments on functional community structure (including microorganisms, detritivore and predatory invertebrates), and on leaf litter decomposition in tank bromeliad ecosystems. Results: Drought or deforestation alone had a moderate impact on biomass at the various trophic level, but did not eliminate species. However, their interaction synergistically reduced the biomass of all invertebrate functional groups and bacteria. Predators were the most impacted trophic group as they were totally eliminated, while detritivore biomass was reduced by about 95%. Fungal biomass was either unaffected or boosted by our treatments. Decomposition was essentially driven by microbial activity, and did not change across treatments involving deforestation and/or drought. Conclusions: Our results suggest that highly resistant microorganisms such as fungi (plus a few detritivores) maintain key ecosystem functions in the face of drought and habitat change. We conclude that habitat destruction compounds the problems of climate change, that the impacts of the two phenomena on food webs are mutually reinforcing, and that the stability of ecosystem functions depends on the resistance of a core group of organisms. Assuming that taking global action is more challenging than taking local-regional actions, policy-makers should be encouraged to implement environmental action plans that will halt habitat destruction, to dampen any detrimental interactive effect with the impacts of global climate change. [ABSTRACT FROM AUTHOR]

Ecosystem services (ES) are essential to sustainable development at multiple spatial scales. Monitoring ES potential (ESP) at the metropolitan level is imperative to sustainable cities. We developed a procedure for long-term monitoring of metropolitan ESP dynamics, utilizing open-source land use land cover (LULC) data and the expert matrix method. We compared the ESP results of 38 European Capital Metropolitan Areas (ECMA) regarding biodiversity integrity, drinking water provision, flood protection, air quality, water purification, and recreation & tourism. Our results show significant declines in ESP across ECMA due to LULC alteration between 2006, 2012, and 2018. We found that ECMA in post-socialist European countries like Poland (Warszawa) have experienced high rates of land use transformation with a remarkable impact on ESP. Surprisingly, we found that Fennoscandinan ECMA, like Helsinki, Stockholm, and Oslo which lead the cumulative ESP ranking, faced the ESP reduction of the highest impact in recent years. The correlation analysis of ESP dynamics to urban expansion and population growth rates suggests that inattentive urbanization processes impact ESP more than population growth. We unveil the implications of our results to the EU and global level agendas like the European Nature Conservation Law and the Sustainable Development Goals. [ABSTRACT FROM AUTHOR]

Upstream migration of the Atlantic blue crab Callinectes sapidus is well described in its native range, but it is little known in invaded areas.Here, we report several long‐distance migration events of the blue crab in the Iberian Peninsula and use a global database to calculate the probability of occurrence of the species in relation to distance to sea. We then exemplify the potential of blue crab impacts on freshwaters by overlapping its probability of occurrence with that of the critically endangered European eel Anguilla anguilla. Finally, we evaluate the extent to which dam barriers can halt the upstream migration of the blue crab.Invasive blue crab has been detected at 108 km from the sea in the Guadalquivir River (the farthest distance reported in the non‐native range), at 71 km in the Guadiana River and at 53 km in the Ebro River. The probability of occurrence decreased steeply in the first upstream kilometres, but it is still concerning at a dozen kilometres from the river mouth (50% at 19 km, 25% at 38 km, and 3% at 100 km). The blue crab invasive potential widely overlaps (63%) with the Iberian range of the European eel. The blocking effect of dams on the potential invasion of freshwater systems by the blue crab was limited (13%).Our study highlights the need to study the upstream migration of the blue crab within its non‐native range, since it could involve serious impacts in reachable river and stream habitats. [ABSTRACT FROM AUTHOR]

The occurrence, abundance, contribution, and size structure of protected and alien fish species were studied in 535 lakes situated in the northern and central parts of Poland in 2014-2021. We hypothesised that protected fish species, due to their status, would be rare in terms of abundance within certain lakes and/or less distributed. Four protected (Cottus poecilopus, Cobitis taenia, Misgurnus fossilis , and Rhodeus amarus) and eight alien species of fish (Ctenopharyngodon idella, Neogobius fluviatilis, Pseudorasbora parva, Acipenser baerii, Carassius gibelio, Ameiurus nebulosus, Hypophthalmichthys molitrix , and Cyprinus carpio) were identified in the studied lakes. Among protected species, the most common and frequent were R. amarus (65% of the studied lakes) and C. taenia (47% of the studied lakes). Other two species (C. poecilopus and M. fossilis) were recorded in one (0.2%) and 18 lakes (3.4%), respectively. Alien species were most often represented by C. gibelio , which occurred in 96 lakes (18% of the studied lakes). The presence of the remaining seven alien species was found in not many lakes (0.2-5.2% of the studied lakes). The abundance of C. gibelio was positively, while A. nebulosus was negatively related to the trophic state of lakes. Cobitis taenia was positively correlated with morphometric parameters of lakes (area and maximum depth). It came as surprise to us that some protected species were quite frequent and sometimes numerous, in contrast to the majority of alien species. [ABSTRACT FROM AUTHOR]

Context: Global change, including land-use change and habitat degradation, has led to a decline in biodiversity, more so in freshwater than in terrestrial ecosystems. However, the research on freshwaters lags behind terrestrial and marine studies, highlighting the need for innovative approaches to comprehend freshwater biodiversity. Objectives: We investigated patterns in the relationships between biotic uniqueness and abiotic environmental uniqueness in drainage basins worldwide. Methods: We compiled high-quality data on aquatic insects (mayflies, stoneflies, and caddisflies at genus-level) from 42 drainage basins spanning four continents. Within each basin we calculated biotic uniqueness (local contribution to beta diversity, LCBD) of aquatic insect assemblages, and four types of abiotic uniqueness (local contribution to environmental heterogeneity, LCEH), categorized into upstream land cover, chemical soil properties, stream site landscape position, and climate. A mixed-effects meta-regression was performed across basins to examine variations in the strength of the LCBD-LCEH relationship in terms of latitude, human footprint, and major continental regions (the Americas versus Eurasia). Results: On average, relationships between LCBD and LCEH were weak. However, the strength and direction of the relationship varied among the drainage basins. Latitude, human footprint index, or continental location did not explain significant variation in the strength of the LCBD-LCEH relationship. Conclusions: We detected strong context dependence in the LCBD-LCEH relationship across the drainage basins. Varying environmental conditions and gradient lengths across drainage basins, land-use change, historical contingencies, and stochastic factors may explain these findings. This context dependence underscores the need for basin-specific management practices to protect the biodiversity of riverine systems. [ABSTRACT FROM AUTHOR]

Background: Aerobic anoxygenic phototrophic (AAP) bacteria are heterotrophic bacteria that supply their metabolism with light energy harvested by bacteriochlorophyll-a-containing reaction centers. Despite their substantial contribution to bacterial biomass, microbial food webs, and carbon cycle, their phenology in freshwater lakes remains unknown. Hence, we investigated seasonal variations of AAP abundance and community composition biweekly across 3 years in a temperate, meso-oligotrophic freshwater lake. Results: AAP bacteria displayed a clear seasonal trend with a spring maximum following the bloom of phytoplankton and a secondary maximum in autumn. As the AAP bacteria represent a highly diverse assemblage of species, we followed their seasonal succession using the amplicon sequencing of the pufM marker gene. To enhance the accuracy of the taxonomic assignment, we developed new pufM primers that generate longer amplicons and compiled the currently largest database of pufM genes, comprising 3633 reference sequences spanning all phyla known to contain AAP species. With this novel resource, we demonstrated that the majority of the species appeared during specific phases of the seasonal cycle, with less than 2% of AAP species detected during the whole year. AAP community presented an indigenous freshwater nature characterized by high resilience and heterogenic adaptations to varying conditions of the freshwater environment. Conclusions: Our findings highlight the substantial contribution of AAP bacteria to the carbon flow and ecological dynamics of lakes and unveil a recurrent and dynamic seasonal succession of the AAP community. By integrating this information with the indicator of primary production (Chlorophyll-a) and existing ecological models, we show that AAP bacteria play a pivotal role in the recycling of dissolved organic matter released during spring phytoplankton bloom. We suggest a potential role of AAP bacteria within the context of the PEG model and their consideration in further ecological models. [ABSTRACT FROM AUTHOR]

It is globally recognized that freshwater anglers can have a decisive role in promoting fish introductions. The aim of this study was to analyze freshwater anglers' actions and perceptions regarding fish introductions, comparing two distinct situations, one with recently arrived non-natives fishes and another with older fish introductions, using the Iberian Peninsula as a case study. To achieve this goal, a bilingual survey was implemented on-line in Portugal and Spain and in person (direct inquiries) in two Iberian regions: Lower Ebro (older fish introductions) in Spain; and Lower Tagus (recent fish introductions) in Portugal. Results showed spatial differences in perceptions and actions, namely about the target species, awareness of the impact of non-native fishes, fish introductions reported and proportion of anglers that wanted new fish species. In the Ebro river there is a high percentage of foreign anglers, higher awareness of fish introduction impact and lower introduction rates reported than in the Tagus river. However, popularity of non-native species like European catfish, was higher in the Ebro. In general, although risk behaviors such as use of fish as life bait was of low prevalence for both countries (approx. 5%), it corresponds to large numbers of fish being introduced. Our conservative estimates revealed 273,600 events of bait discharge per year. Regarding the intentional introductions, we estimated a total of 140,000 intentional introduction (illegal) events per year. These findings may help to improve monitoring, awareness and fisheries management programs led by governmental agencies. [ABSTRACT FROM AUTHOR]

Under the Climate Change scenario, the occurrence of Harmful Cyanobacterial Blooms (HCBs) is an increasingly concerning problem. Particularly for inland freshwaters, that have human populations depending on them for consumption or recreation, HCBs can lead to serious ecological damages and socio-economic impacts, but also to health risks for local communities. From satellite imagery to molecular data, there is an increasing number of methodological approaches that can help improve the monitoring and prediction of cyanobacterial blooms. However, although each methodology has its own strengths and limitations, generally there is a lack of data addressing specific and intraspecific information, which has implications for the modelling and prediction of the real dynamics and toxicity of HCBs. The present review intends to make a quick overview on current approaches to monitor cyanobacterial blooms and provide a tier-based integrative perspective for their application. A transversal monitoring at a wide scale should be enhanced but cannot rely only on pigment levels but rather include the specific and intraspecific diversity information that can be obtained from modern molecular tools. This is crucial to achieve the effective prediction, monitoring and management of HCBs under their increasing occurrence and severity trends in freshwaters. [ABSTRACT FROM AUTHOR]

The evaluation of environmental and spatial influence in freshwater systems is crucial for the conservation of aquatic diversity. So, we evaluated communities of Odonata in streams inside and outside sustainable use areas in the Brazilian western Amazon. We predicted that these streams would differ regarding habitat integrity and species α and β diversity. We also predict that environmental and spatial variables will be important for both suborders, but with more substantial effects on Zygoptera species, considering their nature of forest-specialist. The study was conducted in 35 streams, 19 inside and 16 outside sustainable use areas. The streams outside presented high species richness, abundance, and number of exclusive forest-specialist species from Zygoptera and higher scores of habitat integrity. In contrast, one sustainable use area presented the lowest values of these metrics. Besides, we found that environmental and spatial variables were significantly associated to Zygoptera species composition, but not with Anisoptera, which can be explained by their cosmopolitan nature. Our results indicated that an interplay between environmental and spatial processes determines the structure of the metacommunities of Zygoptera. The less effective dispersal rates and narrow ecological tolerance of Zygoptera species make them more influenced by local conditions and dispersal limitation, and more sensible to habitat modifications. We highlight the importance of improving the local management of the sustainable use areas by environmental agencies, mainly on areas that are losing their capacity to maintain the aquatic fauna, and implementation of social policies toward traditional people. [ABSTRACT FROM AUTHOR]

Cyanobacteria can form blooms and pose a threat to the functioning of freshwater ecosystems. Cyanobacterial invasions are expected to increase due to climate change. Alien species cause a decline in biodiversity by displacing native species, lead to extinctions, affect food webs, and produce cyanotoxins which potentially impact the environment and human health. Three species, Raphidiopsis raciborskii, Sphaerospermospis aphanizomenoides and Chrysosporum bergii, are considered non-native to European waters. Recently, they have expanded their native habitats and become established in temperate lakes. In this article, we provide a detailed overview of the countries where they are distributed and the occurrence of the blooms in Europe. We discuss the biotic and abiotic environmental factors that influence their establishment, as well as the characteristics of the species that make them so adaptable in non-native habitats. Understanding the interplay of these factors will allow us to better recognise patterns of invasiveness and predict their future threats to ecosystems.

Abstract Determining the timing and location of fish reproductive events is crucial for the implementation of correct management and conservation schemes. Conventional methods used to monitor these events are often unable to assess the spawning activity directly or can be invasive and therefore problematic. This is especially the case when threatened fish populations are the study subject, such as the Arctic charr (Salvelinus alpinus L.) populations in Windermere (Cumbria, UK). Arctic charr populations have been studied in this lake since the 1940s, and the locations and characteristics of spawning grounds have been described in detail using techniques such as hydroacoustics, as well as physical and visual surveys of the lake bottom. Here, in conjunction with established netting surveys, we added an environmental DNA (eDNA) metabarcoding approach to assess the spatial distribution of Arctic charr in the lake throughout the year to test whether this tool could allow us to identify spawning locations and activity. Sampling was carried out between October 2017 and July 2018 at three locations in the lake, covering putative and known spawning sites. eDNA metabarcoding provided accurate spatial and temporal characterization of Arctic charr spawning events. Peaks of Arctic charr relative read counts from eDNA metabarcoding were observed during the spawning season and at specific locations of both putative and known spawning sites. Net catches of mature Arctic charr individuals confirmed the association between the Arctic charr spawning activity and the peaks of eDNA metabarcoding relative read counts. This study demonstrates the ability of eDNA metabarcoding to effectively and efficiently characterize the spatial and temporal nature of fish spawning in lentic systems.

Background Together with the intensification of dry seasons in Neotropical regions, increasing deforestation is expected to exacerbate species extinctions, something that could lead to dramatic shifts in multitrophic communities and ecosystem functions. Recent studies suggest that the effects of habitat loss are greater where precipitation has decreased. Yet, experimental studies of the pure and interactive effects of drought and deforestation at ecosystem level remain scarce. Methods Here, we used rainshelters and transplantation from rainforest to open areas of natural microcosms (the aquatic ecosystem and microbial-faunal food web found within the rainwater-filled leaves of tank bromeliads) to emulate drought and deforestation in a full factorial experimental design. We analysed the pure and interactive effects of our treatments on functional community structure (including microorganisms, detritivore and predatory invertebrates), and on leaf litter decomposition in tank bromeliad ecosystems. Results Drought or deforestation alone had a moderate impact on biomass at the various trophic level, but did not eliminate species. However, their interaction synergistically reduced the biomass of all invertebrate functional groups and bacteria. Predators were the most impacted trophic group as they were totally eliminated, while detritivore biomass was reduced by about 95%. Fungal biomass was either unaffected or boosted by our treatments. Decomposition was essentially driven by microbial activity, and did not change across treatments involving deforestation and/or drought. Conclusions Our results suggest that highly resistant microorganisms such as fungi (plus a few detritivores) maintain key ecosystem functions in the face of drought and habitat change. We conclude that habitat destruction compounds the problems of climate change, that the impacts of the two phenomena on food webs are mutually reinforcing, and that the stability of ecosystem functions depends on the resistance of a core group of organisms. Assuming that taking global action is more challenging than taking local-regional actions, policy-makers should be encouraged to implement environmental action plans that will halt habitat destruction, to dampen any detrimental interactive effect with the impacts of global climate change.

The planetary crisis regarding water resources means that new methods are needed to monitor large areas of water basins that are threatened by chemical and natural pollutants, together with climate change. With the aim to detect oil spill, we applied an algorithm, which could consistently and reliably confirm the presence of oil in four polluted lake waters analyzed. Combined algorithm application and metagenomic analysis from the spill areas that had been detected by the satellite identified drivers of the microbial response to oil pollution. Based on ortholog abundances, metabolic pathway reconstruction carried out in PICRUSt2 highlighted the degradative capacity of these microorganism. These microorganisms could be suitable candidates for treatment of crude oil, aromatic hydrocarbons and the desulfurization of persistent petroleum substances like dibenzothiophene.Environmental changes have been analysed with the combination of satellite monitoring and metagenomic in other studies. Red snow phenomenon, in Franz Josef Land's Arctic observed by satellite, is the result of a microbial succession dominated by Chlamydomonas nivalis, a unicellular, red-colored photosynthetic green algae. Similarly, satellite monitoring and metagenomic monitoring were used to assess the impact on coral reefs of a huge quantity of mud spill from iron ore mining on the Abrolhos Bank reef in Brazil.In our study, the combination of satellite sensing and metagenomics analyses offer useful tools for the real-time monitoring of water bodies threatened by oil spills, as well as for the design of recovery strategies based on the use of valuable hydrocarbonoclastic microorganisms.

We studied the development of commercial and recreational fishing on the Kakhovske Reservoir (aka Kakhovka) and the Dnipro (aka Dnieper) River lowlands in 2020–2023. The fish assemblage of the Kakhovske Reservoir is under consideration for the period 1956–2021. The dynamics of the fish population transformation, species extinction, and the emergence of new invasive species are given. The losses in Kakhovske Reservoir’s ecosystem services as a result of the Kakhovska Hydroelectric Power Plant’s (HPP) Dam explosion in June 2023 are analyzed. The states and prospects for local recreational and commercial fishing development are assessed. By field research and monitoring observations of the Kakhovske Reservoir and the Dnipro River lowland using the Earth remote sensing data, it was established that 2 months after the accident, the area of the remained reservoir water surface was ∼430 km2 (about 19% of the initial, including the restored Dnipro River bed). The newly formed shallow waterbodies, which do not have a water connection between each other, occupy an area of about 300 km2. These areas continue to dry out, shrink, and become overgrown with vegetation. The draining of the Kakhovske Reservoir caused an ecological disaster for about 40 species and subspecies of fish. The total monetary losses of commercial fishing are about $5.5 million annually. Losses in fishery from the vanishing of spawning grounds are estimated at 20,000 tons of fish resources (∼$40 million). The negative consequences of the loss of the Kakhovske Reservoir aquatic ecosystems will affect the socio-economic development of the entire South of Ukraine for a long time. Among the major ecosystem services lost is the cessation of water supply. Ukraine’s priority issues are the post-war rehabilitation of the country, its degraded lands, territories, and water areas, and ensuring water and food security. One of the urgent problems will be the feasibility of reconstruction of the Kakhovska HPP’s Dam and restoration of the Reservoir, renovation of water supply, fishery, navigation, energy, and recreation. Biodiversity is a basis for the efficient and sustainable ecosystem functions that provide many ecosystem services, and it should be considered for the post-war recovery and development of Ukraine.

Using strontium (Sr) and barium (Ba) in otoliths to determine natal origins and understand patterns of fish movements is based on the fundamental assumption that otoliths record water chemistry signals without any major alterations. Although prior studies highlighted that fish physiology can modify the water signal in otoliths, studies for freshwater fish are scarce. We exposed different groups of Atlantic salmon parr Salmo salar to different scenarios of ambient-level variations in Sr/Ca and Ba/Ca ratios and then combined otolith chemical profiles with environmental data (water chemistry and temperature), Fulton's index, and otolith growth rates to assess what factors explain/influence the elemental ratios of Sr and Ba in otoliths. Generalized additive mixed models (GAMMs) using water-based otolith composition, temperature, Fulton's index, and "individual" as explanatory variables allow to demonstrate that water chemistry alone cannot fully explain measured ratios in otoliths, except in scenarios involving significant changes in water chemistry. Other factors (physiological effects) should be accounted for reproducing short and minimal seasonal variations in water composition, considering that inter-individual variability contributes quite significantly in most scenarios. [ABSTRACT FROM AUTHOR]

Freshwater ecosystems, including lakes, wetlands, and running waters, are estimated to contribute over half the natural emissions of methane (CH4) globally, yet large uncertainties remain in the inland water CH4 budget. These are related to the highly heterogeneous nature and the complex regulation of the CH4 emission pathways, which involve diffusion, ebullition, and plant-associated transport. The latter, in particular, represents a major source of uncertainty in our understanding of inland water CH4 dynamics. Many freshwater ecosystems harbor habitats colonized by submerged and emergent plants, which transport highly variable amounts of CH4 to the atmosphere but whose presence may also profoundly influence local CH4 dynamics. Yet, CH4 dynamics of vegetated habitats and their potential contribution to emission budgets of inland waters remain understudied and poorly quantified. Here we present a synthesis of literature pertaining CH4 dynamics in vegetated habitats, and we (i) provide an overview of the different ways the presence of aquatic vegetation can influence CH4 dynamics (i.e., production, oxidation, and transport) in freshwater ecosystems, (ii) summarize the methods applied to study CH4 fluxes from vegetated habitats, and (iii) summarize the existing data on CH4 fluxes associated to different types of aquatic vegetation and vegetated habitats in inland waters. Finally, we discuss the implications of CH4 fluxes associated with aquatic vegetated habitats for current estimates of aquatic CH4 emissions at the global scale. The fluxes associated to different plant types and from vegetated areas varied widely, ranging from−8.6 to over 2835.8 mg CH4 m−2 d−1, but were on average high relative to fluxes in non-vegetated habitats. We conclude that, based on average vegetation coverage and average flux intensities of plant-associated fluxes, the exclusion of these habitats in lake CH4 balances may lead to a major underestimation of global lake CH4 emissions. This synthesis highlights the need to incorporate vegetated habitats into CH4 emission budgets from natural freshwater ecosystems and further identifies understudied research aspects and relevant future research directions.

Harmful cyanobacterial blooms (CyanoHABs) impact lakes, estuaries, and freshwater reservoirs worldwide. The duration, severity, and spread of CyanoHABs have markedly increased over the past decades and will likely continue to increase. This article addresses the universal phenomena of cyanobacterial blooms occurring in many freshwater ecosystems worldwide. Based on analysis of ecophysiological traits of bloom-forming cyanobacteria and their interactions with environmental processes, we summarize and decipher the driving forces leading to the initiation, outbreak, and persistence of the blooms. Due to the coupling effects of eutrophication, rising CO2 levels and global warming, a multidisciplinary joint research approach is critical for better understanding the CyanoHAB phenomenon and its prediction, remediation, and prevention. There is an urgent need to evaluate and guide proper use of bloom control techniques at large scales, using science-based and environmentally friendly approaches. [ABSTRACT FROM AUTHOR]

The aims of this study were to investigate the presence, possible sources, and potential ecological risks of synthetic musk fragrances in freshwaters and sediments of the main tributaries of a deep subalpine lake in Northern Italy. The total musk concentrations ranged from few ng L−1 up to values > 500 ng L−1, depending on river characteristics: water flow and the presence of wastewater effluents proved to be the main factors affecting fragrance concentrations. The water flow may indeed dilute fragrance input mainly deriving from treated wastewaters. Good correlations (determination coefficients > 0.60) between synthetic fragrances concentrations and parameters related to anthropogenic impacts confirmed this hypothesis: synthetic fragrances were mainly detected in most polluted rivers crossing urbanized areas. Sediment analysis highlighted accumulation of fragrances in this matrix. Concentrations of synthetic fragrances up to 329 ng g−1 organic carbon were measured in sediments of the most contaminated rivers Boesio and Bardello, which also show the highest nutrient content. The preliminary environmental risk assessment revealed that present levels of synthetic musk fragrances do not pose any risk to the studied environmental compartments. However, a probable medium risk level was evidenced during the dry season in the most contaminated rivers Boesio and Bardello. For these reasons, small rivers draining urbanized watersheds and affected by wastewater effluents should be considered synthetic musk contamination hotspots that warrant further research. [ABSTRACT FROM AUTHOR]

Abstract Background Post-mortem animal predation affects human corpses in various ways. Lesions are a characteristic of the type of terrestrial or aquatic predators. These lesions can be misinterpreted and may be challenging for the forensic pathologist. Different species in freshwater cause different types of lesions depending on their feeding habits. There is a paucity in the literature about post-mortem lesions caused by freshwater animals. Case presentation A 24-year-old man had accidentally drowned while fishing in the River Cauvery. His body was recovered after 3 days. Though the cause of death was drowning, post-mortem animal activity was observed during autopsy, and a live juvenile crab was also found along with the body. Distinct post-mortem lesions caused by decapods Oziotelphusa wagrakarowensis and small fishes Hypselobarbus dubius and Dawkinsia arulius are described. Conclusions Aquatic predators and their activity on the corpse are different from that of terrestrial predators. Knowledge of the local fauna is required to correlate the lesions on the body to the predator.

Microplastics are widespread in freshwater environments and could impact these ecosystems. Bivalves are freshwater organisms that are particularly exposed to microplastic contamination. Therefore, in this preliminary study, the accumulation of microplastics, plasticizers, and additives in the freshwater bivalves Anodonta cygnea was investigated through active biomonitoring. Specimens bought commercially were exposed in three rivers in Central Italy for different exposure times: short (1 month) and long (3 months). The gills and the gastrointestinal tract (GIT) were analyzed separately to evaluate the possible uptake and ingestion of particles via Micro-FTIR. For the first time, small microplastics (SMPs, 5–100 µm), plasticizers, additives, and other micro-litter components, e.g., natural and non-plastic synthetic fibers (APFs), were identified in the bivalve A. cygnea. The most abundant polymer in the gills (94.4%) and in the GITs (66.1%) was polyamide, which had the highest concentration in each river. A decrease in SMPs' abundance was observed over time in the gills in each river, while the abundance in the GIT increased. Compared to polymers, a greater variety of APFs was observed in rivers. The APFs changed during the time of exposure and between different rivers more evidently than polymers, allowing for a clearer identification of the possible sources. These results highlighted the plastic pollution caused by SMPs using freshwater bivalves as sentinel organisms and the need to further investigate the additives that can be proxies of the presence of microplastics in the environment and biota. [ABSTRACT FROM AUTHOR]

Climate and land‐use/land‐cover change ("global change") are restructuring biodiversity, globally. Broadly, environmental conditions are expected to become warmer, potentially drier (particularly in arid regions), and more anthropogenically developed in the future, with spatiotemporally complex effects on ecological communities. We used functional traits to inform Chesapeake Bay Watershed fish responses to future climate and land‐use scenarios (2030, 2060, and 2090). We modeled the future habitat suitability of focal species representative of key trait axes (substrate, flow, temperature, reproduction, and trophic) and used functional and phylogenetic metrics to assess variable assemblage responses across physiographic regions and habitat sizes (headwaters through large rivers). Our focal species analysis projected future habitat suitability gains for carnivorous species with preferences for warm water, pool habitats, and fine or vegetated substrates. At the assemblage level, models projected decreasing habitat suitability for cold‐water, rheophilic, and lithophilic individuals but increasing suitability for carnivores in the future across all regions. Projected responses of functional and phylogenetic diversity and redundancy differed among regions. Lowland regions were projected to become less functionally and phylogenetically diverse and more redundant while upland regions (and smaller habitat sizes) were projected to become more diverse and less redundant. Next, we assessed how these model‐projected assemblage changes 2005–2030 related to observed time‐series trends (1999–2016). Halfway through the initial projecting period (2005–2030), we found observed trends broadly followed modeled patterns of increasing proportions of carnivorous and lithophilic individuals in lowland regions but showed opposing patterns for functional and phylogenetic metrics. Leveraging observed and predicted analyses simultaneously helps elucidate the instances and causes of discrepancies between model predictions and ongoing observed changes. Collectively, results highlight the complexity of global change impacts across broad landscapes that likely relate to differences in assemblages' intrinsic sensitivities and external exposure to stressors. [ABSTRACT FROM AUTHOR]

The impoundment of the Aoos Springs, which was created in 1990 for the needs of hydroelectric production, is characterised by the lack of studies on its fish fauna across years. Seasonal sampling efforts were conducted with Nordic gillnets and an electrofishing device to describe the fish fauna after 30 years from the construction of the impoundment. Our results revealed the presence of establish species in the impoundment and highlighted their connectivity with the inflow streams. The fish fauna has been enriched throughout the years, starting from four observed species few years after the formation of the impoundment (during 1996-1997) to nine species 20 years later (2015-2019). This increase in the number of species across years was mainly attributed to human impacts through unintentional or intentional stocking conducted to support the local recreational fishery. In any case, the importance of each species’ ecological niche and the complexity of freshwater ecosystems should be considered in future initiatives aimed at maintaining fish biodiversity. [ABSTRACT FROM AUTHOR]

We report the first occurrence record of the spiny-cheek crayfish Faxonius limosus in two North-western Italian lakes: Orta and Mergozzo. We also confirm the occurrence of the species in Lake Maggiore. Faxonius limosus is native to the east coast of the USA. Since the end of the 19th century, it was introduced to Europe, where it rapidly spread in Poland, Russia, France, and Germany. In 1991, it was recorded for the first time in Italy in Lake Iseo (Lombardy region; NW Italy), and soon it has spread in Northern and Central Italy. Although Faxonius limosus is included in the list of European Union Concern, only two reports suggested the occurrence of this species in lakes Maggiore, Orta and Mergozzo, but these were never confirmed by experts. The aim of the present paper is to shed light on the distribution of F. limosus along the coasts of the three North-western Italian lakes. To this end, we used visual census and trapping to detect the occurrence of F. limosus, providing also georeferenced and environmental information of its habitat. We discovered 31 new occurrence localities (18 municipalities) for the species, scattered across the three lakes. These new findings highlight the urgency of implementing monitoring and management programs to prevent F. limosus spread and to mitigate its potential ecological impacts. [ABSTRACT FROM AUTHOR]

Recreational fisheries are valued at $190B globally and constitute the predominant way in which people use wild fish stocks in developed countries, with inland systems contributing the main fraction of recreational fisheries. Although inland recreational fisheries are thought to be highly resilient and self-regulating, the rapid pace of environmental change is increasing the vulnerability of these fisheries to overharvest and collapse. Here we directly evaluate angler harvest relative to the biomass production of individual stocks for a major inland recreational fishery. Using an extensive 28-y dataset of the walleye (Sander vitreus) fisheries in northern Wisconsin, United States, we compare empirical biomass harvest (Y) and calculated production (P) and biomass (B) for 390 lake year combinations. Production overharvest occurs when harvest exceeds production in that year. Biomass and biomass turnover (P/B) declined by ∼30 and ∼20%, respectively, over time, while biomass harvest did not change, causing overharvest to increase. Our analysis revealed that ∼40% of populations were production-overharvested, a rate >10× higher than estimates based on population thresholds often used by fisheries managers. Our study highlights the need to adapt harvest to changes in production due to environmental change.

Anthropogenic change at a global scale is affecting life on Earth with impacts on freshwaters. Aquatic hyphomycetes are fungi that drive organic matter decomposition in freshwaters and mediate energy transfer to higher trophic levels. Intraspecific trait variability affects ecological processes and can account for species adaptations to environmental change. To ascertain how aquatic hyphomycetes respond to global change related stressors, we selected 20 strains (7 species), based on their co-occurrence in streams and phylogenetic relatedness. We measured fungal growth rates at different temperatures (7 levels), nutrient concentrations (6 levels) and medium moisture (6 levels). Our results indicate that all stressors affected fungal growth, and responses to nutrient enrichment and moisture were strain specific. Fungal responses to the stressors were not explained by their phylogenetic relatedness. In the absence of stressors, interspecific diversity best explained the variance in fungal traits, while the increase in the stress gradient increased the importance of intraspecific diversity. [ABSTRACT FROM AUTHOR]

The aim of the study was to investigate the modifications of the macroinvertebrate multi-species assemblage in relation to hydromorphological discontinues, since macroinvertebrates are traditionally exploited in water quality assessment activities. Three sampling sites characterized by different hydrological characteristics were selected in five stations along the River Aniene in Central Italy. We evaluated the macroinvertebrate structure, traits, biotic and diversity indices in relation to the erosive power. Among macroinvertebrate taxa, Elminthidae and Chironomidae families showed a particular occurrence pattern associated with the site at the base of vertical drop, characterized by the stronger hydrodynamic. However, the water quality status was high, not showing differences between the three sites. Our finding has a novelty value as similar studies on the investigation of the hydromorphological discontinuities on macroinvertebrate structure and ecological traits are very scarce in the literature. [ABSTRACT FROM AUTHOR]

Dataset contains information on fish occurrences in the Kama River Basin (Russian Federation). The Kama River is the largest tributary (1805 km) of the Volga River and is geographically often considered the main river due to the larger volume of water at their confluence.Dataset is based on our own field studies conducted during 2008-2021. It includes 6,447 occurrences relating to 48 taxa, 46 of which were identified at species level and two at the genus level. All occurrences have coordinates and belong to 13 families of Actinopterygii. All presented data are published for the first time.

Background: Post-mortem animal predation affects human corpses in various ways. Lesions are a characteristic of the type of terrestrial or aquatic predators. These lesions can be misinterpreted and may be challenging for the forensic pathologist. Different species in freshwater cause different types of lesions depending on their feeding habits. There is a paucity in the literature about post-mortem lesions caused by freshwater animals. Case presentation: A 24-year-old man had accidentally drowned while fishing in the River Cauvery. His body was recovered after 3 days. Though the cause of death was drowning, post-mortem animal activity was observed during autopsy, and a live juvenile crab was also found along with the body. Distinct post-mortem lesions caused by decapods Oziotelphusa wagrakarowensis and small fishes Hypselobarbus dubius and Dawkinsia arulius are described. Conclusions: Aquatic predators and their activity on the corpse are different from that of terrestrial predators. Knowledge of the local fauna is required to correlate the lesions on the body to the predator. [ABSTRACT FROM AUTHOR]

Research in limnology is nurtured by the work of many fascinating and passionate women, who have contributed enormously to our understanding of inland waters. Female limnologists have promoted and established the bases of our knowledge about inland waters and fostered the need of protecting the values of those ecosystems. However, on numerous occasions, their contribution to the advancement of limnology has not been duly recognized. Here, we review the presence of women in limnology through the history of the discipline: from the pioneers who contributed to the origins to present day' developments. We aim at visibilizing those scientists and establish them as role models. We also analyze in a simple and illustrative way the current situation of women in limnology, the scientific barriers they must deal with, and their future prospects. Multiple aspects fostering the visibility of a scientist, such as their presence in conferences, awards, or representation in societal or editorial boards show a significant gap, with none of those aspects showing a similar visibility of women and men in limnology. This article raises awareness of the obstacles that women in limnology faced and still face, and encourages to embrace models of leadership, scientific management, and assessment of research performance far from those commonly established. This article is categorized under:Science of Water > MethodsWater and Life > Methods [ABSTRACT FROM AUTHOR]

Rivers that do not flow year-round are the predominant type of running waters on Earth. Despite a burgeoning literature on natural flow intermittence (NFI), knowledge about the hydrological causes and ecological effects of human-induced, anthropogenic flow intermittence (AFI) remains limited. NFI and AFI could generate contrasting hydrological and biological responses in rivers because of distinct underlying causes of drying and evolutionary adaptations of their biota. We first review the causes of AFI and show how different anthropogenic drivers alter the timing, frequency and duration of drying, compared with NFI. Second, we evaluate the possible differences in biodiversity responses, ecological functions, and ecosystem services between NFI and AFI. Last, we outline knowledge gaps and management needs related to AFI. Because of the distinct hydrologic characteristics and ecological impacts of AFI, ignoring the distinction between NFI and AFI could undermine management of intermittent rivers and ephemeral streams and exacerbate risks to the ecosystems and societies downstream. [ABSTRACT FROM AUTHOR]

This study was conducted aiming to record for the first time the occurrence of Mastacembelus notophthalmus Roberts, 1989 in Belitung Island (Indonesia), and update the geographic distribution of this species. Although this species is categorized as LC according to the IUCN Red List, it is rarely reported in fish inventories, with few specimens sampled. Moreover, data on the geographic distribution, population size, and other population details of M. notophthalmus are scarce and insufficient to predict possible threats and propose appropriate conservation measures and policies. A single specimen of Mastacembelus was collected using a fish trap on 20 February 2023, in a swamp, located in the middle course of the Lenggang River, Belitung Island, Indonesia. This specimen was identified as M. notophthalmus and this finding constitutes the southernmost record for this species, expanding its geographic range. In addition, the new record site is about 700 km south-east of the nearest locality in Peninsular Malaysia, about 250 km south-east of the nearest locality in Bangka Island, about 600 km south-east of the nearest locality in Sumatra, and about 500 km south-west from the nearest locality in Borneo. Better ecological and biological data concerning distribution, habitat, and stressors is crucial to reassess the conservation status of M. notophthalmus, and possible future conservation measures and policies. Therefore, we emphasize here the urgency for more comprehensive and accurate data to facilitate conservation assessments and management in Indonesia. [ABSTRACT FROM AUTHOR]

In chlordecone (CLD)-contaminated soils of the French West Indies, if microbial remediation or a physicochemical remediation process, e.g., in situ chemical reduction, is implemented, concentrations of degradation byproducts, such as hydrochlordecones, are expected to increase in the ecosystems. To study their impact in mixtures with CLD, bioassays were carried out. They consisted in evaluating the regenerative capacity of hydra polyps, from a clone whose phylogenetic analysis confirmed that it belonged to the species Hydra vulgaris Pallas, 1766. Hydra gastric sections were exposed to CLD alone or CLD plus dechlorinated byproducts (CLD-BP) for 96 h to assess regeneration. Based on chromatographic analysis, the CLD-BP mix was composed of the 5-monohydrochlordecone isomer (CAS nomenclature), four dihydrochlordecone isomers, and one trihydrochlordecone isomer representing 50%, 47%, and 3% of the total chromatographic area, respectively. A total of 18 mixtures of CLD and CLD-BP were tested. Six environmental concentrations of CLD (2.10−4 μM to 4.10−2 μM) and a similar range of CLD-BP were used. Results from exposures to CLD alone showed the following: (i) a significant decrease in the regenerative capacity of hydra, except at the lowest concentration (2.10−4 μM); (ii) a concentration-independent deleterious effect. The regeneration scores obtained after the exposure to the addition of CLD-BP were not significantly different from those obtained after exposure to CLD alone. Using an experimental design, a modeling of the regeneration scores of hydra exposed to mixtures is proposed. Interpreted carefully, since they are limited to only one type of bioassay, the present results suggest that the situation in the aquatic environments should not become worse in terms of toxicity, if soil remediation programs resulting in the formation of hydrochlordecones are put in place. [ABSTRACT FROM AUTHOR]

The Water Framework Directive (WFD) is the European legislation on water policy that assesses water quality according to time-consuming metrics and specific taxonomic needs. In this sense, the objective of this study was to evaluate the sensitivity of Daphnia magna feeding rate assays to assess/discriminate the water quality of heavily modified and artificial water bodies. Monthly, for one year, the quality of the Crestuma-Lever reservoir (in two sampling sites: Crestuma and Marina) was assessed using physical, chemical, and biological (concentration of chlorophyll-a) elements proposed by the WFD. Additionally, D. magna was exposed to the collected water samples and the feeding rates were evaluated to include an ecosystem function evaluation in water quality assessment. The WFD metrics showed that, overall, the Crestuma-Lever reservoir has a rating of Good to Moderate Ecological Potential, regardless of site. Feeding rates varied with the sampling site and months, demonstrating that feeding behavior evaluation is a sensitive tool that allows discriminate potential effects indicative of a lower water quality. This finding was recorded by the decrease in the feeding rate (Crestuma: May, Sept; Marina: Nov, Jan, May), despite the WFD classification, and once the organisms are affected by the components present in the water samples. [ABSTRACT FROM AUTHOR]

Bacterial communities, microbial populations, and antibiotic resistance of potential pathogens in the water and fish (Cyprinus carpio, flesh and gut) from different areas (A1, A2 and A3—A1 was linked with river water, A2 with cattle activity, and A3 with waters of a spring after heavy rains) of Lake Karla (Thessaly, Central Greece) were investigated. The isolated bacteria were identified using Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) and were tested for resistance in 21 antibiotics. The microbiota composition of fish flesh was also studied using 16S amplicon-based sequencing Serratia fonticola and several species of Aeromonas (e.g., Aeromonas salmonicida, Aeromonas bestiarium, Aeromonas veronii, etc.) exhibited the highest abundances in all studied samples, while the microbiota profile between the three studied areas was similar, according to the culture-dependent analysis. Of them, S. fonticola was found to be resistant in the majority of the antibiotics for the water and fish (gut and flesh), mainly of the areas A1 and A2. Regarding 16S metabarcoding, the presence of Serratia and Aeromonas at genus level was confirmed, but they found at very lower abundances than those reported using the culture-dependent analysis. Finally, the TVC and the rest of the studied microbiological parameters were found at acceptable levels (4 log cfu/mL or cfu/g and 2–4 log cfu/mL or cfu/g, extremely low levels of E. coli/coliforms) in both water and fish flesh. Based on our findings, the water of Lake Karla would be used for activities such as irrigation, recreation and fishing, however, the development and implementation of a quality management tool for Lake Karla, to ensure environmental hygiene and prevention of zoonosis during the whole year, is imperative. [ABSTRACT FROM AUTHOR]

A dataset of 227 oligochaetes and 373 chironomids occurrence records from the subalpine Lake Maggiore, a large and deep temperate lake in Northern-Western Italy and Switzerland was developed within the Interreg Italy-Switzerland 2014-2020 Parchi Verbano Ticino Project (ID:481668) funded by the European Regional Development Fund (ERDF). The lake belongs to the national (LTER-Italy), European (LTER-Europe) and International (ILTER) long-term ecological research networks. Data were collected during the summer-autumn period in 2019-2021. Chironomids (Insecta, Diptera) and oligochaetes (Annelida, Clitellata) were identified to genus/species gr./species level by the authors. All 600 occurrence records are georeferenced and organised in a standardised Darwin Core Archive format. These data gathered along the littoral areas of Lake Maggiore will contribute to the development of common implementation strategies for shared and sustainable water management level of the lake, with particular reference to the protected natural areas (sites belonging to Natura 2000 network in Italy and to the Emerald Network in Switzerland). The authors strongly believe in the great potential of open access occurrence records in biogeographical studies and ecological research in the context of global environmental changes. For that reason, the dataset has been uploaded to the Global Biodiversity Information Facility (GBIF), an intergovernmental free and open access biodiversity data infrastructure.

Functional diversity metrics have been suggested as important indicators of ecosystem functioning. We investigated the effects of land use mediated by local environmental variables on the fish assemblages' functional structure in 18 headwater streams distributed in the Upper Paraná and Iguaçu ecoregions. The species were characterized according to habitat use, food resource use, life history, and hypoxia tolerance. We calculated functional diversity indices [richness (FRic), evenness (FEve), divergence (FDiv), dispersion (FDis), diversity (RaoQ)] and functional rarity indices [distinctiveness (Disti), uniqueness (Uni)], and evaluated the effects of regional and local variables on these indices using generalized linear models. The results highlighted the occurrence of the most functionally distinct and unique species in the forested streams. Moreover, we observed higher FRic in streams sampled in argisol, with a high ammonia load and low habitat diversity. Forested and agricultural covers positively affected FDis and RaoQ. Urban cover had a negative effect on FDis and RaoQ, mainly due to the increase in generalist functional groups in urban streams. Our findings emphasize the importance of forested cover in maintaining specialized species in fish assemblages of streams and preserving functional diversity and ecosystem functioning. Furthermore, these results contribute to direct conservation and recovery measures in freshwater environments. [ABSTRACT FROM AUTHOR]