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Negative impacts from aquatic invasive plants in the United States include economic costs, loss of commercial and recreational use, and environmental damage. Simulation models are valuable tools for predicting the invasion potentials of species and for the management of existing infestations. We developed a spatially explicit, agent-based model representing the invasion, growth, and senescence of aquatic weeds as functions of day length, water temperature, water depth, and the response of aquatic weeds to biological control. As a case study to evaluate its potential utility, we parameterized the model to represent two historical invasions (1975–1983 and 2004–2007) of Hydrilla (Hydrilla verticillata (L. fil.) Royle) in Lake Conroe, Texas, USA, and their subsequent biological control using grass carp (Ctenopharyngodon idella). Results of several hypothetical alternative management schemes indicated that grass carp stocking densities needed to control Hydrilla infestation increased exponentially as the lag time between initial invasion and initial stocking increased, whereas stocking densities needed to control infestation decreased as the amount of time allowed to control the infestation increased. Predictions such as those produced by our model aid managers in developing proactive management plans for areas most likely to be invaded. [ABSTRACT FROM AUTHOR]

We describe a stem group representative of Gaviiformes (loons or divers) from the early Eocene London Clay of Walton-on-the-Naze (Essex, UK). The holotype of Nasidytes ypresianus gen. et sp. nov. is a partial skeleton including the mandible and all major limb bones. The new species is the oldest unambiguously identified loon and the most substantial Palaeogene fossil record of Gaviiformes. The mandible of Nasidytes is proportionally wider than that of extant loons and resembles that of extant coots (Fulica spp.), which indicates that the new taxon was less piscivorous than crown group Gaviiformes. Hypotarsus morphology suggests that N. ypresianus is the sister taxon of a clade including all other Cenozoic fossil loons and crown group Gaviiformes. According to its plesiomorphic leg morphology, and unlike extant loons, the new species was not a specialized pursuit predator of fishes. The evolution of advanced diving capabilities in the stem lineage of Gaviiformes is likely to have been correlated with an increased piscivory of loons, and the skeletal morphology of Nasidytes conforms to multiple independent origins of specialized piscivory and a highly aquatic ecology in the waterbird clade (Aequornithes). [ABSTRACT FROM AUTHOR]

River water and sediment embody environmental characteristics that give valuable information about the eco-environment. Due to rapid unplanned urbanization and industrialization, the aquatic environment of any urban river can be seriously polluted by heavy metals. Four heavy metals (As, Cr, Cd, and Pb) were analyzed in surface sediments and water from the Kirtankhola River located in the coastal area of Bangladesh. The decreasing pattern of metals was observed as Cr > Pb > As > Cd in both water and sediment. The heavy metal ranges were 1.67–7.31, 12.64–45.69, 0.01–1.59, and 8.03–35.68 μg/L in the water and 2.09–6.89, 14.76–47.08, 0.01–1.77 and 6.37–41.43 mg/kg in sediments for As, Cr, Cd, and Pb. The number of metals tested in water samples surpassed the acceptable limits of drinking water quality, indicating that water from this river is not safe for drinking and cooking and could pose a risk to the riverine ecosystem. The pollution load index (PLI) values were close to one, indicating that the sediment of the study river was low contamination. Contamination factor (CF) has reported that As, Cd, and Pb have been moderate to extremely polluted by sediment samples and metals level implied that the condition is much alarming and probably severely affecting the aquatic ecology of this riverine ecosystem. [ABSTRACT FROM AUTHOR]

The shape and relative size of an ocular lens affect the focal length of the eye, with consequences for visual acuity and sensitivity. Lenses are typically spherical in aquatic animals with camera-type eyes and axially flattened in terrestrial species to facilitate vision in optical media with different refractive indices. Frogs and toads (Amphibia: Anura) are ecologically diverse, with many species shifting from aquatic to terrestrial ecologies during metamorphosis. We quantified lens shape and relative size using 179 micro X-ray computed tomography scans of 126 biphasic anuran species and tested for correlations with life stage, environmental transitions, adult habits and adult activity patterns. Across broad phylogenetic diversity, tadpole lenses are more spherical than those of adults. Biphasic species with aquatic larvae and terrestrial adults typically undergo ontogenetic changes in lens shape, whereas species that remain aquatic as adults tend to retain more spherical lenses after metamorphosis. Further, adult lens shape is influenced by adult habit; notably, fossorial adults tend to retain spherical lenses following metamorphosis. Finally, lens size relative to eye size is smaller in aquatic and semiaquatic species than other adult ecologies. Our study demonstrates how ecology shapes visual systems, and the power of non-invasive imaging of museum specimens for studying sensory evolution. [ABSTRACT FROM AUTHOR]

Riparian deforestation degrades stream habitats, altering fish assemblages' structure, and composition. In contrast, secondary riparian forests can recover stream habitats and fish assemblages as they recover structural attributes and ecological processes. We evaluated whether the amount and condition of secondary riparian forests were important to conserve fish assemblages in 49 streams sites in eastern Amazonia. We related fish assemblage taxonomic and functional measures to riparian forest amount plus different habitat metrics using regression analysis. We compared assemblage measures among reference forests, abandoned pastures (open canopy), and secondary forests (closed canopy) using ANOVA tests. The amount of secondary forests had little influence on fish assemblages. Species richness, diversity, and functional richness were higher in pasture than in reference sites but returned to pre-disturbance conditions in secondary sites. However, functional evenness was lower in pasture streams and did not recover after secondary forest regrowth. Our results show that secondary riparian forest condition is important to recover some aspects of fish assemblages. However, streams bordered by these forests may have impoverished fish assemblages because some lost sensitive species may take longer to return. Avoiding riparian deforestation is the best strategy to reduce losses in aquatic biodiversity and ecosystem functions in tropical agricultural landscapes. [ABSTRACT FROM AUTHOR]

Stable isotope analysis is ubiquitous as a method to investigate food-web dynamics at various scales in aquatic ecology. Most studies make use of dorsal muscle tissue, which involves lethal sampling of the fish. The sampling of muscle tissue is often followed by chemical lipid extraction pre-treatment before stable isotope analysis. In this study we tested whether stable light isotope results obtained from fin tissue were comparable to those from muscle, and we investigated whether lipid correction could be used as a substitute for lipid extraction. Various lipid correction equations were evaluated. Based on our results, we propose ethical and efficient methods of sample collection and preparation for stable isotope analysis of freshwater fish. We found that dorsal muscle and fin tissue samples could yield similar interpretations of freshwater food-web dynamics in South Africa, demonstrating that fin clippings might be more widely applied as a nonlethal sampling method for stable isotope studies. Existing lipid correction equations either over- or underestimated true lipid extracted δ13C values, therefore an amended lipid correction equation is proposed as it was successfully tested against a population of wild fish. The errors arising from existing lipid correction equations suggest that site-specific calibration should be employed. [ABSTRACT FROM AUTHOR]

Phytoplankton is a organisms with characteristic as primary producers and bioindicator of marin and fresh waters. Mangrove waters and open waters generally have different characteristics of ecosystem and organism that live in these waters. The research aim to determine the difference of phytoplankton in mangrove waters and open waters including diversity, uniformity, and dominance of two type of waters. This research was conducted in Desember 2020. The sampling locations take out in two sampling areas which are mangrove waters and open waters in th Mengkapan Village, Sungai Apit District, Siak Regency. Data identifications and analysis carried out in aquatic ecology laboratory of Faculty of Fisheries and Marine Science, University Riau. The comparison of the data of phytoplankton abundance uses the PAST application and Microsoft Excel (T-Test). The range of abundance of phytoplankton in Mengkapan Village waters is between 576-856 sel/L with Bacillariophyceae as the dominant class. There is no significant difference between the two waters, but the water Mengkapan Village has low water quality and influences the phytoplankton abundance. [ABSTRACT FROM AUTHOR]

The biodiversity–ecosystem function hypothesis postulates that higher biodiversity is correlated with faster ecosystem process rates and increased ecosystem stability in fluctuating environments. Exhibiting high spatiotemporal habitat diversity, floodplains are highly productive ecosystems, supporting communities that are naturally resilient and highly diverse.We examined linkages among floodplain wetland habitats, invertebrate communities and their associated traits, and ecosystem function across 60 sites within the floodplain wetlands of the lower Wolastoq | Saint John River, New Brunswick, using structural equation modelling and Threshold Indicator Taxa ANalysis.We identified key environmental filters structuring invertebrate communities, by linking increased niche differentiation through shoreline change, flood pulse dynamics, and macrophyte bed complexity with increased taxa and functional diversity.Examination of traits linked to ecosystem functions revealed that more resilient wetlands with balance between primary productivity and decomposition as carbon sources were associated with greater functional evenness and richness, while habitat patches with elevated decomposition rates had lower functional richness, reflecting a simplified, more disturbed habitat.While our more complex overarching SEM model was ultimately compromised by an overspecified number of pathways, our results nevertheless are indicative of a divergence between wetland and riverine ecosystems in their relationships linking biodiversity and ecosystem function, illustrating how to define ecosystem health in wetland habitats, and demonstrating how critical functions support healthy wetland habitats by providing increased resilience to disturbance. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Climate warming is a ubiquitous stressor in freshwater ecosystems, yet its interactive effects with other stressors are poorly understood. We address this knowledge gap by testing the ability of three contrasting null models to predict the joint impacts of warming and a range of other aquatic stressors using a new database of 296 experimental combinations. Despite concerns that stressors will interact to cause synergisms, we found that net impacts were usually best explained by the effect of the stronger stressor alone (the dominance null model), especially if this stressor was a local disturbance associated with human land use. Prediction accuracy depended on stressor identity and how asymmetric stressors were in the magnitude of their effects. These findings suggest we can effectively predict the impacts of multiple stressors by focusing on the stronger stressor, as habitat alteration, nutrients and contamination often override the biological consequences of higher temperatures in freshwater ecosystems. [ABSTRACT FROM AUTHOR]

Turtles have a highly modified body plan, including a rigid shell that constrains postcranial anatomy. Skull morphology and neck mobility may therefore be key to ecological specialization in turtles. However, the ecological signal of turtle skull morphologies has not been rigorously evaluated, leaving uncertainties about the roles of ecological adaptation and convergence. We evaluate turtle cranial ecomorphology using three‐dimensional geometric morphometrics and phylogenetic comparative methods. Skull shape correlates with allometry, neck retraction capability, and different aquatic feeding ecologies. We find that ecological variables influence skull shape only, whereas a key functional variable (the capacity for neck retraction) influences both shape and size. Ecology and functional predictions from three‐dimensional shape are validated by high success rates for extant species, outperforming previous two‐dimensional approaches. We use this to infer ecological and functional traits of extinct species. Neck retraction evolved among crownward stem‐turtles by the Late Jurassic, signaling functional decoupling of the skull and neck from the shell, possibly linked to a major episode of ecomorphological diversification. We also find strong evidence for convergent ecological adaptations among marine groups. This includes parallel loss of neck retraction, evidence for active hunting, possible grazing, and suction feeding in extinct marine groups. Our large‐scale assessment of dietary and functional adaptation throughout turtle evolution reveals the timing and origin of their distinct ecomorphologies, and highlights the potential for ecology and function to have distinct effects on skull form. [ABSTRACT FROM AUTHOR]

Spring viremia of carp virus (SVCV) is globally widespread and poses a serious threat to aquatic ecology and aquaculture due to its broad host range. To develop effective agents to control SVCV infection, we selected 16 naturally active small molecules to assess their anti-SVCV activity. Notably, dihydroartemisinin (DHA) (100 μmol/L) and (S, S)-(+)-tetrandrine (TET) (16 μmol/L) exhibited high antiviral effects in epithelioma papulosum cyprinid (EPC) cells, with inhibitory rates of 70.11% and 73.54%, respectively. The possible antiviral mechanisms were determined as follows: 1. Preincubation with DHA and TET decreased viral particle infectivity in fish cells, suggesting that horizontal transmission of SVCV in the aquatic environment was disrupted; 2. Although neither had an effect on viral adhesion, TET (but not DHA) interfered with SVCV entry into host cells (>80%), suggesting that TET may have an antiviral function in early viral replication. For in vivo study, both agents enhanced the survival rate of SVCV-infected zebrafish by 53.3%, significantly decreased viral load, and modulated the expression of antiviral-related genes, indicating that DHA and TET may stimulate the host innate immune response to prevent viral infection. Overall, our findings indicated that DHA and TET had positive effects on suppressing SVCV infection by affecting early-stage viral replication, thus holding great potential as immunostimulants to reduce the risk of aquatic rhabdovirus disease outbreaks. [ABSTRACT FROM AUTHOR]

Mixing processes downstream of river confluences impacts the ecology and the related environmental management of river networks. A clear understanding of such processes is challenging, especially for confluences having width‐to‐depth ratios larger than 100, due to the limited available field data. In this study, four field surveys based on hydro‐acoustic and conductivity measurements were conducted near the confluence between the Yangtze River and the Poyang Lake, which are the largest river and freshwater lake in China, respectively. It was found that mixing dynamics at the confluence were controlled by a complex interaction among the momentum flux ratio, secondary flow and the lock‐exchange flow associated to the density contrast between the two tributaries. Slow mixing was observed during high‐flow conditions that generated dual counter‐rotating secondary cells, with the downwelling flow acting as a barrier in the post‐confluence channel. In contrast, more rapid mixing was observed during low‐flow conditions when only a single channel‐scale secondary flow was identified. The mixing processes were also affected by the lock‐exchange flow associated to the density difference between the two confluent flows. Such lock‐exchange enhanced mixing when the Yangtze River waters had higher temperature, that is, lower density than that of the Poyang Lake. In low flow condition, the penetration of the much larger momentum flux of Yangtze River created a "two‐layers" structure with the contribution of the density difference, which further enhanced the curvature‐induced helicity. The findings from the present study improve our current understanding of mixing dynamics in large river confluences. Plain Language Summary: The confluence between the Yangtze River and the Poyang Lake, which are the largest river and the largest freshwater lake in China, respectively, is one of the largest on the Earth. Understanding this mixing processes at such large‐scale river confluence is significantly important for local flood control and aquatic ecology management, but even challenging due to the lack of detailed field data. Four field surveys were conducted to investigate hydrodynamics, water quality and mixing at the confluence of the Yangtze River and Poyang Lake. The effect of momentum and density difference between the two rivers and large‐scale secondary flow on mixing processes was identified. The results of the present study indicated that such density difference can produce different patterns of vertical stratification which are related to the mixing between the Yangtze River and the Poyang Lake. Key Points: Four field surveys on the mixing process downstream of a large river confluence were conductedDifferent mixing patterns were distinguished based on conductivity and hydro‐acoustic measurementsMixing dynamics around the confluence were controlled by the momentum flux ratio, secondary flow and the lock‐exchange [ABSTRACT FROM AUTHOR]

The capability of Scenedesmus dimorphus for biodegradation of crude oil components is evaluated using biological and biochemical techniques. After exposure of the algal cells to different concentrations of crude oil for 21 day, growth parameters such as cell number as well as fresh and dry weights have increased at low concentrations of crude oil (up to 0.04%) in comparison with control samples. However, growth criteria have decreased in response to the increase in crude oil concentration (0.08%–1%). Similar trends are observed in the content of chlorophylls, carotenoids, flavonoids, anthocyanins, and phenols. Crude oil treatment induces the production of H2O2 and thiobarbituric acid reacting substances. Moreover, enhancing crude oil concentration results in increasing activities of superoxide dismutase, polyphenol oxidase, peroxidase, and lipoxygenase. In comparison, the activities of catalase, ascorbate peroxidase, and phenylalanine ammonia lyase increase at low concentrations (up to 0.02%) and then decrease. Using gas chromatography–mass spectrometry analysis several biodegradation intermediate compounds are recognized in the culture media over treatment time. Altogether, S. dimorphus shows considerable potential for biodegradation of crude oil components particularly at concentrations lower than 0.08%. Thus, this microalga can be used as a competent phytoplankton in removal of crude oil from contaminated water supplies. [ABSTRACT FROM AUTHOR]

Bis(4-hydroxyphenyl)methanone (BHPM), a common ultraviolet stabilizer and filter (USF), is extensively added in sunscreens; however, BHPM is proven as an endocrine disruptor, posing a serious threat to aquatic ecology, and BHPM should be then removed. As sulfate radical (SO4•−) could be useful for eliminating emerging contaminants, oxone appears as a favorable source reagent of SO4•− for degrading BHPM. Even though cobalt is a useful catalyst for activating oxone to generate SO4•−, it would be even more promising to utilize ambient-visible-light irradiation to enhance oxone activation using cobaltic catalysts. Therefore, in contrast to the conventional cobalt oxide, cobalt titanium oxide (CTO) was investigated for chemical and photocatalytic activation of oxone to eliminate BHPM from water. Especially, a special morphology of nanosheet-assembled configuration of CTO was designed to maximize active surfaces and sites of CTO. Thus, CTO outperforms Co3O4 and TiO2 in degrading BHPM via oxone activation. Furthermore, the substituent of Ti enabled CTO to enhance absorption of visible light and possessed a much smaller Eg. These photocatalytic properties intensified CTO's activity for oxone activation. CTO possessed a significantly smaller Ea of degradation of USFs than other catalytic systems. Mechanistic insight for degrading BHPM by CTO + oxone was explicated for identifying contribution of reactive oxygen species to BHPM degradation. The BHPM degradation pathway was also investigated and unveiled in details via the DFT calculation. These results validated that CTO is a superior cobaltic alternative for activating oxone to eliminate BHPM. [ABSTRACT FROM AUTHOR]

Humic substances are ubiquitous materials found in terrestrial and aquatic ecosystems. Humic acids, a diagenetic product can interact with various components present in aquatic sediments. The present research is on the evaluation of sedimentary humic acids from the Krossfjorden glacial fjord situated within the Svalbard archipelago. The results of this study are needed to understand the structural characteristics of humic acids isolated from the fjord. Surface sediment samples were collected from four stations throughout the fjord during a summer period in 2018. Various spectroscopic techniques such as UV-visible, Fourier-transform infrared spectroscopy (FTIR), and Nuclear magnetic resonance spectroscopy (NMR) were applied for studying the humic acids. The elemental composition as well as the presence of tannin and lignin were also analyzed. The results of this study revealed the variation in the structure of humic acids from aliphatic to aromatic from the outer to the inner region of the fjord. This change in humic acids was well supported by the FTIR and NMR results with differences in the spectrums. [ABSTRACT FROM AUTHOR]

Animal migration is one of the most spectacular and visible behavioural phenomena in nature with profound implications for a range of ecological and evolutionary processes. Successful migration hinges on the ability to exploit temporary resources (e.g. food) and evade threats (e.g. predators) as they arise, and thus the timing of migration is often regarded as a dominant predictor of individual migratory success.However, with the exception of intensively studied taxa (mainly birds), relatively few studies have investigated inter‐individual annual and seasonal variation in migratory timing and performance, or tested predictions on how migration across high and low predation‐risk habitats may exert selection on migratory timing. In particular, studies that assess the survival consequences of variation in migratory timing remain rare, which is most likely due to the logistical challenges associated with monitoring survival success and population‐level characteristics simultaneously.Here, we address the above‐mentioned questions using roach Rutilus rutilus, a fish that migrates from lakes characterised by high predation risk into low‐risk streams during winter. Specifically, we used individual‐based tracking of roach in two European lake systems over multiple migration periods (9 and 7 years respectively), to obtain highly detailed (year‐round scheduling, repeat journeys and the fate of individuals) data on the variability/synchrony of migratory timing in spring and autumn respectively.We report seasonal differences in the variability of migratory timing, with lower variance and higher migration synchrony in spring lake arrival timing as compared to autumn lake departure timing. Furthermore, the timing of autumn migration is more variable across years than the timing of spring migration. Second, we find that later arrival to the lake habitat is positively associated with apparent survival from 1 year to the next, whereas we found no effect of lake departure timing on survival probability.These findings represent rare evidence showing how intraspecific variation in timing in migratory fish differs across years and seasons, and how variation in timing can translate into survival consequences for prey in systems characterised by high predation risk. [ABSTRACT FROM AUTHOR]

Professor William E. Walton (1956–2020) was a giant in the field of mosquito control through wetland management. His early work in aquatic ecology led to an outstanding academic career in the Department of Entomology, at the University of California, Riverside, where mosquitoes became the unifying feature of his varied research. Underpinned by a solid basic science foundation, the primary focus of his studies was non-chemical control of mosquitoes via habitat design and manipulation, natural enemies, bacterial larvicides, growth regulators, and fungi. This paper presents a summary of his scientific contributions to the fields of aquatic ecology, medical entomology, and toxicology, highlighting his laboratory and field-based research findings. The full version of this manuscript that includes Bill's entire body of work is available as Supplemental Material accompanying the online article. [ABSTRACT FROM AUTHOR]

The compositional characteristics of dissolved organic matter (DOM) have important implications for lake water quality and aquatic ecology. Seasonal changes of dissolved organic matter (DOM) as well as phytoplankton abundance and composition in Shahu Lake from April to July were characterized by three-dimensional fluorescence spectroscopy (3DEEMs) combined with parallel factor (PARAFAC) analysis. The relationship between the response of components of the DOM and phytoplankton abundance were explored via Pearson correlation and redundancy analysis (RDA) in the overlying water. The results showed that the DOM was composed mainly of tryptophan-like (C2+C4), fulvic-acid-like (C3), humic-acid-like (C1), and tyrosine-like (C5) compounds that accounted for 44.47%, 20.18%, 20.04%, and 15.31%, respectively, of the DOM. The DOM was derived from both endogenous and terrestrial sources. With seasonal changes, endogenous DOM produced by phytoplankton growth and metabolism gradually increased. In spring and summer (April–July), Chl-a concentrations were significantly correlated with C3 (p < 0.01) and C5 (p < 0.05). The concentration of protein-like fractions (C2+C4, C5) were correlated with Cyanobacteria abundance, and the concentrations of humic-like component content (C1, C3) were correlated with the abundance of Xanthophyta, Chlorophyta, and Cryptophytes. Overall, phytoplankton density and Chl-a content increased by 125% and 197%, respectively, and the abundance of C3 and C5 in the DOM increased by 7.7% and 22.15% in parallel. Thus, seasonal phytoplankton growth had an important influence on the composition of the DOM. [ABSTRACT FROM AUTHOR]

Nitrate (NO3 – ) pollution has a significant effect on aquatic ecology. This study aimed to remove NO3 – from water using heterotrophic denitrification. Denitrification performance using three different leaves as carbon sources for heterotrophic denitrification were investigated in side-by side microcosm studies, including leaves of Ginkgo biloba (Gb, Gingko), Firmiana simplex (Fs, Sycamore), and Cerasus serrulata (Cs, Oriental cherry). Results showed that leaves can reduce and remove nitrate from water with various removal efficiencies at varying dosages for different species of leaves. Compared to gingko and sycamore, oriental cherry presented a higher denitrification rate. Furthermore, anaerobic digestion experiment for the leaves revealed that the biodegradability and bioavailable of oriental cherry was higher than those of gingko and sycamore. Therefore, oriental cherry was selected for a continuous experiment, in which the influence of hydraulic retention time (HRT) on NO3 – removal was investigated. When the HRT was 6 h, NO3 – was not completely removed, while NO3 – was removed at HRT = 12 h, with no accumulation of NO2 – or NH4 + even at low temperatures. Results demonstrated that oriental cherry can effectively reduce nitrate from water to the allowable range of water quality under the appropriate HRT. Therefore, oriental cherry leaf-mediated heterotrophic denitrification is a suitable denitrification process for NO3 – removal from water. [ABSTRACT FROM AUTHOR]

• A gas permeable membrane electrode assembly was developed. • It integrated anode and cathode on each side of gas permeable membrane, respectively. • It was assembled in a stacked transmembrane electro-chemisorption system. • It enhanced ammonia recovery from wastewater via in situ utilization of authigenic acid and base. • It showed features of excellent performance, energy saving and easy scale-up. Ammonia recovery from wastewater is of great significance for aquatic ecology safety, human health and carbon emissions reduction. Electrochemical methods have gained increasing attention since the authigenic base and acid of electrochemical systems can be used as stripper and absorbent for transmembrane chemisorption of ammonia, respectively. However, the separation of electrodes and gas permeable membrane (GPM) significantly restricts the ammonia transfer-transformation process and the authigenic acid-base utilization. To break the restrictions, this study developed a gas permeable membrane electrode assembly (GPMEA), which innovatively integrated anode and cathode on each side of GPM through easy phase inversion of polyvinylidene fluoride binder, respectively. With the GPMEA assembled in a stacked transmembrane electro-chemisorption (sTMECS) system, in situ utilization of authigenic acid and base for transmembrane electro-chemisorption of ammonia was achieved to enhance the ammonia recovery from wastewater. At current density of 60 A/m2, the transmembrane ammonia flux of the GPMEA was 693.0 ± 15.0 g N/(m2·d), which was 86 % and 28 % higher than those of separate GPM and membrane cathode, respectively. The specific energy consumption of the GPMEA was 9.7∼16.1 kWh/kg N, which were about 50 % and 25 % lower than that of separate GPM and membrane cathode, respectively. Moreover, the application of GPMEA in the ammonia recovery from wastewater is easy to scale up in the sTMECS system. Accordingly, with the features of excellent performance, energy saving and easy scale-up, the GPMEA showed good prospects in electrochemical ammonia recovery from wastewater. [Display omitted] [ABSTRACT FROM AUTHOR]

Many studies have reported the influence of dispersal processes on aquatic bacterial communities, but the role of community coalescence is still unknown in sediment-laden rivers. Here, we examined the assembly of distinctive bacterial communities (free-living [FL], particle-attached [PA], and surface-sediment [SS]) with differing habitat preferences across different regions of the Yellow River (China) in the spring and autumn of 2019. We demonstrated that in both seasons SS bacteria featured the highest diversity, followed by PA bacteria, and then FL bacteria. Nonetheless, both FL and PA groups showed remarkable seasonal variation in water samples, while the SS group in sediment samples showed significant spatial variation. Furthermore, species sorting and dispersal limitation respectively governed the biogeographic patterns (strong distance–decay relationships) of water and sediment bacterial communities. With respect to community coalescence, not only the same habitats (i.e., water–water, particle–particle, and sediment–sediment) but also similar habitats (i.e., water–particle) had higher proportions of overlapped amplicon sequence variants (ASVs) compared with different habitats (i.e., water–sediment and particle–sediment). Moreover, the proportions of overlapped ASVs between PA and SS groups were higher than those between FL and SS groups. Network analysis revealed that the SS group harbored the highest network complexity, followed by PA and FL groups. Most connectors in the networks were identified as FL–PA–SS ASVs irrespective of the river reaches sampled. These findings demonstrate the biogeographic patterns of distinctive bacterial communities driven by species sorting and dispersal limitation, and provide evidence for bacterial community coalescence in the Yellow River’s water and sediment. Bacteria attached to suspended particles may play a paramount role in the microbial ecology of different habitats in large sediment-laden rivers.

Due to dam discharge, waterfalls, sudden increases in water temperature and oxygen production by photosynthesis, the total dissolved gas (TDG) in water is often supersaturated, which may have serious effects on aquatic ecology. When the atmospheric pressure is lower than the TDG pressure in water, the supersaturated dissolved gas in water will slowly release into air. Wall-attached bubbles were formed during the TDG release process. The generation and departure of wall-attached bubbles influence the release process of TDG in water. To simulate the growth period of the wall-attached bubbles under different pressures, a decompression experimental device was designed to record the supersaturated TDG release process. Based on experimental data and mathematical calculations, the quantitative relationship between the bubble growth rate and environmental pressure was obtained. The supersaturated TDG dissipation rate increases monotonically with increasing relative vacuum degree. Applied the calculation method about the wall-attached bubble growth rate, a formula of the supersaturated TDG adsorption flux was proposed, and a prediction method of the TDG release coefficient was established. The simulation results show that with the increasing relative vacuum degree, the TDG release coefficient increases correspondingly, and the adsorption from wall surface area can be obviously promoted. This study provides an important theoretical basis for the accurate calculation of the TDG release process and provides a scientific basis for the accurate prediction of the spatial and temporal distribution of supersaturated TDG under different pressure and solid wall conditions. [ABSTRACT FROM AUTHOR]

Around 36,000 km3 of freshwater flows through rivers and estuarine ecosystems and enter the world's coastal fishing regions every year. The flow of freshwater and sediments creates regional changes in coastal circulation, stimulates marine productivity and helps define the hydrologic properties of estuarine and oceanic waters. These processes can affect different life stages of marine species either directly, through variations in salinity and temperature, or indirectly, due to changes in the availability of food and habitat. This paper reviews the relationship between freshwater flowing through estuarine and coastal ecosystems, and the variable productivity associated with global marine capture fisheries. The results of a global synthesis revealed that 72% of species representing 77% of the total catch (43 million tonnes) were linked to river flows for at least some part of their life cycle. Insights into how the relationship between flow and fishery production varies globally indicates wild capture fisheries and freshwater resources would benefit from an integrated planning and management approach. [ABSTRACT FROM AUTHOR]

Among vertebrates, teleosts display a wide array of sex determination and differentiation mechanisms ranging from chromosomal sex determination on one end of the spectrum to environmental sex determination on the other end. However, the interplay of both these mechanisms is also not uncommon. Several gonochoristic fishes exhibit gonadal plasticity often resulting in sex reversal. The major manipulation of sex differentiation in teleost is affected by sex steroids. In this context, the increasing contamination of aquatic ecosystems by estrogen-like compounds, commonly known as xenoestrogens, is of major concern. This often leads to deleterious effects on the reproductive success of fish and thereby adversely impacts aquatic biodiversity. In the present review, we have focused on impact of xenoestrogen at different levels of the reproductive system influencing not only gonadal differentiation in teleosts but also their reproductive functions. The review would also explore the mitigation strategies and regulations in place for aquatic xenoestrogen management. [ABSTRACT FROM AUTHOR]

Seldom investigated for its biodiversity, the biomonitoring of Lake Ahémé is expected to increase in future and a prerequisite is the design of an appropriate sampling strategy. Here, we assessed macroinvertebrate assemblages in relation to environmental conditions in Lake Ahémé during the short and long wet seasons (SWS and LWS, respectively). This will help optimise sampling strategies for the future, when sampling only during the SWS or the LWS. A total of 4049 macroinvertebrates from 28 families and 32 genera were collected. Abundance was significantly higher at sites sampled during the SWS. Molluscs were the most dominant taxon and accounted for 92.8% of individuals collected during this study. This was followed by annelids, insects and crustaceans representing 3.7%, 3.2% and 0.3% of the total abundance, respectively. Biodiversity indices showed a significantly higher diversity in the SWS and higher spatial variation in the macroinvertebrate community. The first three axes of the non‐metric multidimensional scaling revealed spatial changes in the macroinvertebrate community during the SWS and LWS. These changes were driven by salinity, conductivity, pH, temperature, dissolved oxygen and water depth. No taxa could be assigned as indicators in the LWS whereas diverse brackish and freshwater species characterised the SWS. As a result, when considering sampling during the wet seasons, SWS sampling should suffice for a qualitative study whereas an accurate ecological investigation requires both SWS and LWS. [ABSTRACT FROM AUTHOR]

Two slow-moving developments are threatening reservoir aquatic habitats globally: aging and climate change. These events are projected to transform reservoir aquatic habitats in various and often unpredictable ways. Aging affects in-lake habitats directly, whereas climate change affects both in-lake and off-lake conditions. Climate change is expected to accelerate and, in some instances, possibly decelerate aging. Aging can be indexed as functional age, an index that signals the position of a reservoir along its lifespan relying on in-lake descriptors of aquatic habitat. Using existing habitat datasets and climate projections, we developed semi-quantitative predictions about the effect of climate change on reservoir functional age in the USA. Driven by increased warming, functional age was predicted to increase latitudinally from south to north with no obvious longitudinal gradient. Functional age also changed with precipitation, increasing latitudinally from south to north and longitudinally in the east and west but decreasing in the central USA. Our projections are tentative because of the uncertain nature of reservoir aging and climate change sciences, as well as the inexactness of available data and models. We review general strategies suitable for systematically dealing with the unpredictable and constantly changing conditions expected to occur this century as reservoirs certainly continue to get older, within the scope of uncertain climate change projections. [ABSTRACT FROM AUTHOR]

The invasive alien species (IAS) are widely recognized as a significant threat to marine biodiversity and severely affect ecosystem services. There has been no measurable global assessment of their impacts and routes of introduction. This review highlights some aspects of invasive species and their impacts on the ecosystem in general. For many roots like global transportation, biological pest control, climate changes, and sometimes commercial, invasive species are introduced into the new environments. Afterward, the invasive species are rapidly dominant over the indigenous species because of their first growth, rapid reproduction, ecological competence, and phenotypic plasticity, consequently, altering the structure of Ecosystems and deterring the biological and physical organization of the system. Many policies have been introduced to stop the destruction produced by invasive animals and plants and to prevent upcoming invasions. Some critical components of getting rid of invasion are concern about transporting wildlife to new areas, Ballast water in tankers, aquarium species, and shipping. [ABSTRACT FROM AUTHOR]

This study was conducted to assess the faunal diversity in Gorai Creek of Mumbai, India from August 2019 to July 2020. The data collected month wise were pooled together and transformed into three seasons [Monsoon (June to September), Winter (October to February), and Summer (March to May)] and this seasonal data were used for the study of biodiversity pattern. Using the average seasonal species occurrence data as input the following biodiversity indices, S, N, d, J', H'(loge), 1-Lambda, Delta, Delta*, Delta+, sDelta+, Lambda+, Phi+ & sPhi+ were calculated by using PRIMER (v7.0). It revealed that 90 species of fauna under 70 genera, 50 families, 29 orders, 6 classes and 3 phyla were found to occur in the creek. The order-wise representation of identified fauna was found to be 7 ichthyofaunas, 4 pelecypods, 6 gastropods, 2 cephalopods, 1 shrimp and 1 stomatopod along with 8 avifauna. The present study results indicated that the Gorai Creek ecosystem is endowed with moderate biodiversity that needs to be conserved. [ABSTRACT FROM AUTHOR]

Wetlands are periodically flooded terrestrial and aquatic environments, which provide benefits to a community known as ecosystem services (ESs). This research identified, classified, and spatialized the level of relevance of ecosystem services provided by wetlands in the Galinhos-Guamaré semi-arid estuarine system, State of Rio Grande do Norte, Northeast Brazil. ESs were analyzed using the Common International Classification of Ecosystem Services (CICES), v.4.3, and geographic information system (GIS) using a mosaic of Sentinel-2A images. The services provided by wetlands were classified into provision, regulation and maintenance, and cultural sections, with six divisions, 12 groups, and 22 classes being identified. The capacity of a number of wetlands to provide services was identified in 34 mangrove forests, 32 estuaries, 30 tidal flats, 26 solar saltworks, 23 apicum (tidal flats), and seven in shrimp ponds. However, it is noteworthy that these habitats are associated with ecosystems with great ecological, socioeconomic, and cultural importance, where the general approach presented here requires more detailed research in each macrohabitat, which should be considered as a priority for conservation. [ABSTRACT FROM AUTHOR]

The focus of this study is the dynamics of interaction between commensal and host species in an aquatic ecological system with harvesting, and stochastic attributes. The progress and the stability of the system, as well as the dynamics of the commensal host relationship are examined. The stabilities at steady states are also examined. We discuss the possible harvesting strategies described by the various attributes. The possibility of existence of bio-economic equilibrium with optimal scheme is being discussed. We provided the analytical estimates of the population intensities of fluctuations by Fourier transform methods through stochastic perturbation. Some numerical simulations are also carried out to make lawful the analysis. [ABSTRACT FROM AUTHOR]

Chemical information has an important role in the sensory ecology of aquatic species. For aquatic prey, chemical cues are a vital source of information related to predator avoidance and risk assessment. For instance, alarm cues are released by prey that have been injured by predators. In addition to providing accurate information about current risk, repeated exposure to alarm cues can elicit a fear response to novel stimuli (neophobia) in prey. Another source of chemical information is disturbance cues, released by prey that have been disturbed or harassed (but not injured) by a predator. While disturbance cues have received much less attention than alarm cues, they appear to be useful as an early warning signal of predation risk and have the potential to be used as a priming cue for learning. In this study, we used wood frog (Lithobates sylvaticus) tadpoles to test whether repeated exposure to disturbance cues during the embryonic stage can induce neophobic behaviour. Three weeks following repeated exposure to disturbance cues, tadpoles showed reduced activity when exposed to a novel odour, but they no longer displayed an antipredator response to disturbance cues. In a second experiment, we found that tadpoles failed to learn that a novel odour was dangerous following a pairing with disturbance cues, whereas alarm cues facilitated such learning. Our results add to the growing body of information about disturbance cues and provide evidence of their function as an embryonic risk cue but not as an associative learning cue. [ABSTRACT FROM AUTHOR]

Aquaculture's role has expanded over the past two decades, with the industry contributing to nearly 50% of the overall fish production. Aquaculture production in Asia and Africa contributes a significant share of total global aquaculture output growth. Aquaculture supports livelihoods and income improvement in a number of states, despite the fact that economic situations have indeed been unfavourable and environmental concerns remain undeniable. To meet the growing demand for fish, aquaculture must expand. However, this expansion will not be sustainable unless management and planning are significantly improved. Local, national, and international management are needed to address the social, economic, and environmental problems. These provide the foundation to proper aquaculture management strategies. In considering the involved ecology, water quality, and genetics, aquaculture can have a detrimental impact on the environmental sustainability. This paper highlights the review on site selection with capacity evaluation, analysis of threats and risks, as well as certification and standards, which are all important considerations in achieving a sustainable aquaculture industry. [ABSTRACT FROM AUTHOR]

Despite growing interest in river and catchment restoration, including a focus on nature-based solutions, assessing effectiveness of restoration programmes continues to prove a challenge. The development of the Eddleston Water project, the Scottish Government's empirical study of the impact of implementing natural flood management measures on flood risk and habitat restoration, provides the opportunity to review restoration monitoring at a strategic and operational level for this long-running catchment restoration programme. The project has implemented an extensive range of restoration measures along the river and across the 69 km2 catchment. This paper reviews the monitoring strategy and assesses both how the monitoring network developed meets its strategic aims and what subsequent changes were made in monitoring design and implementation. Covering hydrology, hydromorphology and ecology, we explore how all three are integrated to provide a comprehensive assessment of restoration success. Lessons to help inform other river rehabilitation monitoring programmes include the importance of a scoping study and capturing the full range of environmental variables pre-restoration; the limitations of BACI designs; and the need to focus integrated monitoring on a process-based framework and impact cascade, whilst also covering the full trajectory of recovery. [ABSTRACT FROM AUTHOR]

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Penguins lost the ability to fly more than 60 million years ago, subsequently evolving a hyper-specialized marine body plan. Within the framework of a genome-scale, fossil-inclusive phylogeny, we identify key geological events that shaped penguin diversification and genomic signatures consistent with widespread refugia/recolonization during major climate oscillations. We further identify a suite of genes potentially underpinning adaptations related to thermoregulation, oxygenation, diving, vision, diet, immunity and body size, which might have facilitated their remarkable secondary transition to an aquatic ecology. Our analyses indicate that penguins and their sister group (Procellariiformes) have the lowest evolutionary rates yet detected in birds. Together, these findings help improve our understanding of how penguins have transitioned to the marine environment, successfully colonizing some of the most extreme environments on Earth. This study examines the tempo and drivers of penguin diversification by combining genomes from all extant and recently extinct penguin lineages, stratigraphic data from fossil penguins and morphological and biogeographic data from all extant and extinct species. Together, these datasets provide new insights into the genetic basis and evolution of adaptations in penguins. [ABSTRACT FROM AUTHOR]

Although cyanobacteria are commonly associated with eutrophic lakes, they are the basic components of phytoplankton communities in lakes that have different trophic statuses. In inland waters, both nutrient loading from watersheds and warmer conditions promote phytoplankton growth and cause extensive cyanobacterial blooms. Certain bloom-forming cyanobacterial species can pose a health risk to humans and aquatic ecosystems through cyanotoxin production. The aim of this study was to evaluate the cyanobacterial composition and toxins in five reservoirs and two natural lakes in the Küçük Menderes River Basin, all with varying trophic statuses. Within this scope, samples were collected in autumn 2017 and spring 2018. Cyanobacterial species were enumerated according to the Utermöhl method. Cyanotoxin samples were analyzed using HPLC. To find the trophic status of the water bodies, the Trophic State Index (TSI) developed by Carlson (1977) was used and Total Phosphorus (TP), Secchi Depth (SD), and Chlorophyll-ɑ (chl-ɑ) measurements were performed. Cyanobacterial abundance, species composition, and cyanotoxin production differed significantly between the lakes and reservoirs. A total of 13 cyanobacteria species were identified including potential cyanotoxin producers such as Microcystis, Aphanizomenon, and Dolichospermum. According to the TSI, three reservoirs were mesotrophic and the other four waterbodies had eutrophic-hypereutrophic conditions. Microcystis is the most common bloom-forming freshwater cyanobacteria in the Küçük Menderes River Basin. However, microcystin concentrations were relatively low and the highest microcystin concentration was detected in the Tahtalı Reservoir at 9 µg/L. The Küçük Menderes River Basin is under water-stressed conditions and the cyanobacteria blooms in the region might pose another threat for wildlife and humans. [ABSTRACT FROM AUTHOR]

This review paper aimed to summarize the climate change impacts on water sources and their relation with human and ecosystem health and evaluate better management strategies. In aquatic environments, climate change causes alteration of biodiversity and species distribution, changes in the duration of biological functions, decreasing productivities, alteration in food web structures, as well as triggering the invasion of various species, and variation in the presence, abundance, and concentrations of various co-stressors. Since the beginning of the 20th century, the surface water temperature in the oceans has risen by about 1°C. Consequently, human well-being is directly and indirectly affected by these alterations. The World Health Organization (WHO) estimates 3.5 million people die from water-related diseases each year. It is projected that the number of water-related diseases will increase due to the effects of climate change. To cope with these problems, alternative water management strategies should be developed to have resilient water systems in terms of both ecological and technological perspectives. Thus, water management requires the cooperation of many sectors including citizens, institutions, public and private sectors, etc. within a multi-stakeholder approach. [ABSTRACT FROM AUTHOR]

Simple Summary: In the current study, we estimate the genetic diversity of the salangid Neosalanxtaihuensis sampled from 11 populations in the six typical river basins of China. Using the COI gene sequencing technology, the N. taihuensis population's genetic difference within and between river basins was investigated. Significant levels of genetic subdivision were detected among populations within basins rather than between basins. Population history dynamics showed that N. taihuensis populations experienced a population expansion during the glacial period in the late Pleistocene. These results suggest that different populations should be considered as different management units to achieve effective conservation and management purposes. The salangid Neosalanx taihuensis (Salangidae) is a commercially important economical fish endemic to China and restricted to large freshwater systems with a wide-ranging distribution. This fish species has continuous distribution ranges and a long-introduced aquaculture history in Chinese basins. However, the research on its population genetic differentiation within and between basins is very limited. In this regard, 197 individuals were sampled from 11 populations in the Nenjiang River Basin (A1–A4), Songhua River Basin (B1), Yellow River Basin (C1–C2), Yangtze River Basin (D1), Lanchang River Basin (E1–E2) and Huaihe River Basin (F1). Based on the COI sequence, the N.taihuensis population's genetic difference within and between river basins was investigated. The haplotypes and their frequency distributions were strongly skewed, with most haplotypes (n = 13) represented only in single samples each and thus restricted to a single population. The most common haplotype (H4, 67/197) was found in all individuals. The analysis of molecular variance (AMOVA) revealed a random pattern in the distribution of genetic diversity, which is inconsistent with contemporary hydrological structure. The mismatch between the distribution and neutrality tests supported the evidence of a population expansion, which occurred during the late Pleistocene (0.041–0.051 million years ago). Significant levels of genetic subdivision were detected among populations within basins rather than between the six basins. Population history dynamics showed that N. taihuensis experienced an expansion during the glacial period in the late Pleistocene. Therefore, different populations should be considered as different management units to achieve effective conservation and management purposes. These results have great significance for the evaluation and exploitation of the germplasm resources of N. taihuensis. [ABSTRACT FROM AUTHOR]

Khor Al-Zubair lagoon is a vital water body in southern Iraq. Despite the existence of a number of environmental studies in this region, it lacks searches related to the diversity of diatoms especially benthic forms, in light of global climatic changes and their impacts on aquatic ecosystems. Therefore, this research was designed to document diatom species that began to colonize this lagoon. The present study was carried out during the period from January to November 2020 in two selected stations at Khor Al-Zubair lagoon, where five species of diatoms were documented and described, including Amphora acuta, Biremis ambigua, Cyclotella litoralis, Lyrella lyra var. subcarinata, and Progonoia musca. The species, C. litoralis is a new record for Iraqi diatom flora. [ABSTRACT FROM AUTHOR]

The presence of Antibacterial in the aquatic environment is a major concern because of the effect of Antibacterial on water quality, aquatic organisms and human health. The current study aims to detect Antibacterial (Amoxicillin, Ciprofloxacin, and Levofloxacin) seasonally in water, sediments, muscles and liver of Nile tilapia fish during the period from November 2020 to August 2021 in two selected stations in Shatt Al-Arab, Basrah, Iraq. The samples were analyzed using high performance liquid chromatography (HPLC), High concentrations of the antibiotic Ciprofloxacin (CIP) were recorded in each of the water, sediment and fish muscle samples during the spring season at the second station, reaching the 24.9 mg l-1, 24.5 mg. kg-1, 7.4 mg. kg-1, respectively, while the high concentration of Amoxicillin (AMO) Antibacterial was 4.1 mg.kg-1 in liver of fish in spring season in the second station. The presence of Antibacterial in the aquatic environment in such high concentrations is a source of great concern. The study recommends conducting more studies to measure Antibacterial contamination in other areas of the Shatt al-Arab and the Iraqi marshes. [ABSTRACT FROM AUTHOR]

HMD is widely used by industry in the manufacture of polyamide materials, as well as a substance in the production of epoxy resins and other substances. At the same time, HMD is a physiologically active, toxic and dangerous substance (hazard class II), which can cause burns, eczema-like dermatitis, diseases of the nervous system and gastrointestinal tract in humans. Wastewater contaminated with HMD, which is discharged into natural reservoirs, causes the death of aquatic organisms and aquatic vegetation, degrades the quality of water, which becomes unusable. HMDA is listed as a hazardous substance by the European Chemicals Agency and the American Conference of Government Hygienists of Industry. [ABSTRACT FROM AUTHOR]