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Mercury is a hazardous pollutant of global concern. While advances have been made in identifying the detrimental effects caused by Hg species in phytoplankton, knowledge gaps remain regarding the metabolomic perturbations induced by inorganic mercury (Hg(II)) and monomethylmercury (MeHg) in these organisms. Diatoms represent a major phytoplankton group essential in various global biogeochemical cycles. The current study combined targeted metabolomics, bioaccumulation, and physiological response assays to investigate metabolic perturbations in diatom Cyclotella meneghiniana exposed for 2 h to nanomolar concentrations of Hg(II) and MeHg. Our findings highlight that such exposures induce reprogramming of the metabolism of amino acids, nucleotides, fatty acids, carboxylic acids and antioxidants. These alterations were primarily mercury-species dependent. MeHg exposure induced more pronounced reprogramming of the metabolism of diatoms than Hg(II), which led to less pronounced effects on ROS generation, membrane permeability and chlorophyll concentrations. Hg(II) treatments presented distinct physiological responses, with more robust metabolic perturbations at higher exposures. The present study provides first-time insights into the main metabolic alterations in diatom C. meneghiniana during short-term exposure to Hg species, deepening our understanding of the molecular basis of these perturbations.

Drier and hotter conditions linked with anthropogenic climate change can increase wildfire frequency and severity, influencing terrestrial and aquatic carbon cycles at broad spatial and temporal scales. The impacts of wildfire are complex and dependent on several factors that may increase terrestrial deposition and the influx of dissolved organic matter (DOM) from plants into nearby aquatic systems, resulting in the darkening of water color. We tested the effects of plant biomass quantity and its interaction with fire (burned vs. unburned plant biomass) on dissolved organic carbon (DOC) concentration and degradation (biological vs. photochemical) and DOM composition in 400 L freshwater ponds using a gradient experimental design. DOC concentration increased nonlinearly with plant biomass loading in both treatments, with overall higher concentrations (>56 mg/L) in the unburned treatment shortly after plant addition. We also observed nonlinear trends in fluorescence and UV-visible absorbance spectroscopic indices as a function of fire treatment and plant biomass, such as greater humification and specific UV absorbance at 254 nm (a proxy for aromatic DOM) over time. DOM humification occurred gradually over time with less humification in the burned treatment compared to the unburned treatment. Both burned and unburned biomass released noncolored, low molecular weight carbon compounds that were rapidly consumed by microbes. DOC decomposition exhibited a unimodal relationship with plant biomass, with microbes contributing more to DOC loss than photodegradation at intermediate biomass levels (100-300 g). Our findings demonstrate that the quantity of plant biomass leads to nonlinear responses in the dynamics and composition of DOM in experimental ponds that are altered by fire, indicating how disturbances interactively affect DOM processing and its role in aquatic environments.

Humans increasingly dominate Earth's natural freshwater ecosystems, but biomass production of modified ecosystems is rarely studied. We estimate potential fish total standing stock in USA reservoirs is 3.4 billion (B) kg, and approximate annual secondary production is 4.5 B kg y-1. We also observe varied and non-linear trends in reservoir fish biomass over time, thus previous assertions that reservoir fisheries decline over time are not universal. Reservoirs are globally relevant pools of freshwater fisheries, in part due to their immense limnetic footprint and spatial extent. This study further shows that reservoir ecosystems play major roles in food security and fisheries conservation. We encourage additional effort be expended to effectively manage reservoir environments for the good of humanity, biodiversity, and fish conservation.

The genus Ulva is one of the most commonly commercially cultivated seaweeds both on land in ponds and in the open sea. As a crop, its cultivation is accompanied by three pest groups: (1) diseases caused by pathogenic bacteria, algae, virii, and fungi, which cause perforations, deterioration, and decreased growth of thalli; (2) various grazers, e.g. small crustaceans, gastropods, and non-defined invertebrates, which decrease growth and damage the thalli; and (3) an epiphytic biofilm of microorganisms, which also causes damage to the end-crop decreasing its yield and value. Mitigation categories against Ulva pests may be divided into three categories: (A) pro-active human intervention by washing the infected thalli with acid, fresh water, proprietary chemicals or CO2-saturated seawater, the use of methanolic Ulva extracts, or exudate from the green seaweed, all of which are reported to restrict pest activity; (B) using the beneficial properties of probiotic bacteria thereby eliciting antifouling activity, with selective abilities against pathogens of Ulva spp.; (C) enhancing the effects of environmental changes on pests, i.e. acidification and increased seawater temperature, which mainly decrease the grazer population and thereby their pressure. A summary of these studies is presented as a guide for rapid responses and applied management techniques for the amelioration of cultivation diseases, grazers, and harmful epiphytes affecting the foliose green alga Ulva spp. [ABSTRACT FROM AUTHOR]

To clarify the differences between migratory and non‐migratory salmonids during the parr‐smolt transformation, we conducted experiments on steelhead (SH) and rainbow trout (RT) Oncorhynchus mykiss. We examined relationships among different parameters of osmoregulatory, endocrine, immune, and stress‐related regulation in these fish following free selection of salinities. For this, we used an experimental halocline aquarium in which the upper layer was filled with fresh water and the lower with seawater. There was no significant difference between the two trout strains in terms of the number of fish in the final positions after the overnight trial. However, the time spent by each fish in the lower tank during the overnight trial was significantly longer in SH than in RT. Additionally, the time spent by each fish in the lower tank and plasma cortisol concentration were significantly correlated in RT, but not in SH. Similarly, plasma osmolality after the trial had a significant positive correlation with plasma cortisol concentration in RT, but not in SH. The plasma cortisol and mRNA levels of sodium‐potassium ATPase‐α3 in the gill were negatively correlated, as were several types of cortisol receptors in the gill and brain, in RT. Meanwhile, the genes expressed in SH were positively correlated with plasma cortisol. In SH, plasma cortisol was also significantly correlated with immune and stress‐related factors, which was not seen in RT. Our results suggest that the studied factors are important to behavioral and physiological differences in anadromy among salmonid species. [ABSTRACT FROM AUTHOR]

Gastrotrichs of the genus Chaetonotus Ehrenberg, 1830 (Chaetonotida, Chaetonotidae) are known to be a speciose and pervasive group in both the marine and freshwater ecosystems, and recent investigations indicate that there is a significant amount of species diversity yet to be discovered. In the present study, a new species of this genus is described from two quarry lakes in northern Italy and characterized using an integrative morphological and molecular approach. Chaetonotus polites n. sp. is recognized by a rather stocky body, a five-lobed head, and the cuticular covering resolved in 13 alternating columns of partially imbricated scales, trilobed on the head and pentagonal on the trunk; each scale bears a peculiar simple, very thick, curved spine with a truncated apex. The new species is also distinguished by four putative molecular apomorphies at the 18S rRNA gene and two at the 28S rRNA gene. The location and type of these unique traits in the predicted secondary structure of the ribosomal genes is provided. The phylogenetic analysis based on concatenated sequences of three genes (the nuclear 18S and 28S rRNA genes and the mitochondrial COI gene) derived from 123 selected chaetonotidans, including the novel species, confirms that the genus Chaetonotus is a polyphyletic group, with several of its members resolved together with species of other genera. The new species forms a cluster with species of the subgenus Hystricochaetonotus Schwank 1990, suggestive of its potential stem lineage. [ABSTRACT FROM AUTHOR]

Artificial ponds can be important reproductive sites for anurans in human-disturbed habitats. However, this capacity depends on the configuration of the habitat where they are inserted. We evaluated how anuran beta diversity was influenced by the configuration of the surrounding habitat and water parameters in artificial ponds in southern Brazil. Physicochemical parameters of water and the configuration of the surrounding habitat were the elements that best explained the variation in beta diversity. However, the surrounding habitat had a predominant role in the differences between communities. The level of exposed soil was the component that best acted on the turnover component of beta diversity followed by urbanization, which highlights the impact of human presence on anuran diversity. In other words, we observed that anthropogenic changes caused changes in species composition in the evaluated ponds. Among water parameters, only phosphate was relevant for the configuration of communities. Phosphate peaks may result from sewage or fertilizer contamination, not infrequent in the region despite the low human density and the small-scale agriculture economy. Even though they are anthropogenic environments, artificial ponds can help maintain the anuran communities, but their effectiveness will depend on the presence of forest remnants and water quality. [ABSTRACT FROM AUTHOR]

The interconnectedness of adjacent freshwater and terrestrial ecosystems results in 'tangled‐webs', where the cross‐boundary exchange of materials results in energy flows that provide critical resources for ecosystem productivity. However, these energy flows can be disrupted by anthropogenic activities, resulting in modified ecosystem functioning.A ubiquitous anthropogenic activity in fresh waters is recreational angling. Five major angling activities can disrupt the structure of the 'tangled‐web' to produce an 'angled‐web' (a tangled food web that is modified by angling activities). (1) Fish stocking increases the number and species available to exploit, but the increased fish abundances can have strong top‐down effects and disrupt reciprocal prey subsidies. Following capture, fish are either (2) harvested or (3) released alive ('catch‐and‐release0'); both can both drive eco‐evolutionary changes that can modify food‐web structure. Where fish are exploited using baited hooks, (4) the release of 'ground‐bait' is used as a fish attractant; its composition of novel protein and carbohydrate sources form novel trophic links in the food web and can accelerate eutrophication. Some angling styles also require (5) riparian and in‐stream vegetation to be cleared to minimise gear fouling, potentially modifying fish spawning and nursery areas.We suggest that each of these angling impacts (and their interactions) can contribute to transforming the 'tangled web' into an 'angled‐web', with the strength and direction of the transformation dependent on angling pressure, prevailing fishery practices, regulations and management, and the extent of the interaction effects of the activities. These interactions and their impacts will vary globally given angling methods, practices and regulations differ across the world.We argue that, in this era of substantial environmental change driven by climate change, habitat loss and nutrient enrichment of fresh waters, the extent to which angling impacts food webs should not be overlooked and underappreciated. We emphasise that when freshwater angling activities are poorly managed and/or unregulated, they can strongly modify the interconnectedness between terrestrial and freshwater food webs. [ABSTRACT FROM AUTHOR]

An investigation of freshwater fungi in Thailand resulted in the collection and isolation of a coelomycetous Seriascoma from submerged wood. The combined ITS and LSU sequence data placed the taxon within the sexual morphic Seriascoma acutisporum strains, ZHKUCC 22-0273 and ZHKUCC 22-0274, with high bootstrap support and confirmed the asexual morphic stage of the taxon. Seriascoma acutisporum MFLUCC 24-0091 shares the generic characteristics of having an immersed, eustromatic conidiomata and phialidic, cylindrical to ampulliform, hyaline, aseptate conidiogenous cells bearing hyaline conidia, but with smaller conidiomata and locules compared to other coelomycetous Seriascoma species. [ABSTRACT FROM AUTHOR]

Migration timing is critical for diadromous fish, especially for survival. Migration through fresh water and estuarine transitional waterbodies may be an important early life survival bottleneck through potential exposure to anthropogenic pressures and predators. Monitoring smolt movement and survival through riverine and estuarine habitats is important for identifying causes of smolt mortality and the potential for directing focused, mitigating management actions. Acoustic telemetry was used to track 186 Atlantic salmon smolts during migration from the river Boyne to the Irish Sea on the east coast of Ireland during 2019–2021. Migration success from release to sea entry that ranged from 47% to 81% was linked to biotic (predation) and abiotic effects (water flow and water temperature). Predation was associated with interannual variation in smolt survival, with 5.4% of smolts consumed by marine mammals and 26.3% lost to unknown fates. Our findings contribute to the understanding of predation on smolts and also how water temperature, flow and tidal phase can influence this critical life stage of Atlantic Salmon, a species in decline across its range. [ABSTRACT FROM AUTHOR]

Water masses are carriers of anthropogenic fingerprints in the ocean interior, with their property changes manifesting oceanic thermodynamic responses to climate change. Yet, delimiting ocean water masses remains challenging in either observational atlas or climate models. This study analyzes the distribution of Indian Ocean seawater in the density–spicity space and uses volumetric maxima and minima between σ = 27.1 and 27.4 kg m−3 to track the cores and boundaries of intermediate water masses, respectively. In addition to the well-known Antarctic Intermediate Water (AAIW) and Red Sea–Persian Gulf Intermediate Water (RS-PGIW), two other water masses are identified by the new approach. One is the Indian-AAIW (I-AAIW), as a mixture of the AAIW and the Indonesian Throughflow water, existing in the South Equatorial Current and the Agulhas Current system. The other [equatorial Indian Intermediate Water (EIIW)] exits in the equatorial Indian Ocean and Bay of Bengal, sourced from the RS-PGIW and overlying fresh waters. These waters are corroborated by nutrient and dissolved oxygen data. Around half (26 out of 51) of phase 6 of the Coupled Model Intercomparison Project (CMIP6) models can reasonably simulate these intermediate water masses. Compared with the observed water masses, the intermediate water masses in models are of a smaller thickness and the RS-PGIW is colder and fresher. The former arises from a warm bias in the thermocline, whereas the latter is likely linked to insufficient ventilation in the Red Sea and Persian Gulf in models owing to coarse grid resolution and a surface cold bias. Significance Statement: Oceanic water masses are important for understanding climate change. Yet, the definition of water masses is controversial. Here, we use volumetric minima in the density–spicity space to track the boundaries of intermediate (27.1–27.4 kg m−3) water masses in the Indian Ocean. We identify four water masses: AAIW, I-AAIW, EIIW, and RS-PGIW. We delineate the geographical location of each water mass, including two newly identified water masses (I-AAIW and EIIW). We also examined the performance of 51 CMIP6 models in simulating these water masses and found that 26 models can reasonably simulate the distribution of these water masses. There are two systematic model biases emerging from these models. The intermediate water masses in models are of a thinner thickness arising from a warm bias in the thermocline, and the RS-PGIW is colder and fresher owing to insufficient ventilation in the Red Sea and Persian Gulf. These results provide a useful benchmark for understanding water masses in a changing climate and constraining climate models. [ABSTRACT FROM AUTHOR]

Recent large-scale spatial products have been developed to assess wetland position in the tidal frame, but nationwide comparisons and validations are missing for these products. Wetland position within the tidal frame is a commonly used characteristic to compare wetlands across biogeomorphic gradients and factors heavily into wetland vulnerability models. We utilize a dataset of 365 surface elevation table stations across the conterminous USA containing ground-surveyed tidal datum and elevation data to validate two gridded, conterminous USA–wide relative tidal elevation products. We identified substantial differences between our ground-surveyed dataset and the gridded products, with the Gulf coast exhibiting the greatest error (p < 0.0001, n = 140). Error in relative tidal elevation products varied by coast, tidal range, and latitude. These differences in errors indicate that gridded relative tidal elevation products may be more accurate in coastal wetlands with larger tidal ranges (> 30 cm) and are less accurate in freshwater wetlands near the coast. This paper makes advances in understanding why relative tidal elevation differences occur among national datasets and identifies areas of future work that could support more robust vulnerability models. [ABSTRACT FROM AUTHOR]

Aotearoa New Zealand's aquatic ecosystems are declining despite widespread awareness of mitigation needs. This study employs storytelling to address this issue, testing the role of the messenger in encouraging freshwater restoration in rural catchment communities. We quantified peer-to-peer knowledge exchange on three cognitive processes (retention and extraction of information, motivation to reproduce modelled restoration behaviour, and recall of acquired information), using ArcGIS® 'StoryMaps'. We created two restoration stories; one told through the voice of a respected catchment group member known for leadership, and one through a collective catchment group voice. We surveyed freshwater community members (N = 82) before and after reading the stories, and one month later, and found that participants reading either catchment restoration story (1) accepted both the catchment collective and the respected individual member as a trusted source, and could therefore relate to either, and (2) thought the story was informative and contained new details, independent of the time span land holders have been actively restoring. While our study found no significant differences between individual or collective storytellers, it confirms the value of trusted messengers as restoration knowledge brokers in rural catchment communities, a critical step in value-led freshwater restoration at large scales. [ABSTRACT FROM AUTHOR]

Forward Osmosis (FO), a membrane desalination technology and Capacitive Deionization (CDI), an electrically operated desalination technology, are numerically integrated utilizing four different configurations for the high-water recovery rate and ultrapure water production from brackish water resource. To minimize the wastewater rejection, the CDI desorption stream is continuously fed to the FO unit, efficiently recovering the remaining freshwater. To produce ultrapure water, freshwater stream obtained from FO is provided to the CDI cell, which adsorbs the remaining dissolved solute particles. These two configurations serve the purpose of both industrial as well as domestic water supply requirements. Continuing this concept, the formation of the other two configurations allows us to obtain fresh water and ultrapure water simultaneously and up to a 90% freshwater recovery rate for the areas with inadequate supply. The performance parameters to assess the integration are the Water Recovery Rate (WRR) and Specific Energy Consumption (SEC). The first configuration (CDI-FO), proposed for a high freshwater recovery rate, resulted in 79.33% WRR with an SEC of 0.689 ${\bi \; }{\rm kWh}/{\rm m}^3$ kWh / m 3 . While, for the second configuration (FO-CDI), 34.25% water was recovered as 2.87 ppm ultrapure water along with 34.25% freshwater. The third proposed configuration (CDI-FO-CDI) had a WRR of 79.33%, 14.67% of which was recovered as ultrapure water of concentration 2.86 ppm. The fourth configuration (CDI-FO-FO) developed for high water recovery, removed the maximum of water from the feed stream with a WRR of 91.33% and remained energy-efficient, consuming an SEC of 0.908 $\; {\rm kWh}/{\rm m}^3$ kWh / m 3 . [ABSTRACT FROM AUTHOR]

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Solar evaporation attracted lots of attention due to its environment-friendly and high efficiency, which is a potential approach to collecting fresh water. Many efforts have been made to improve the evaporation rate in the open space. While the actual water collection rate is far less than the evaporation rate, especially in passive water collection, limiting its practical and scalable applications. In this review, we focus on freshwater collection based on solar evaporation. Firstly, heat and mass transfer behaviors on the evaporation side were summarized to improve evaporation performance, including heat transfer processes in thermal radiation, convection, and conduction; mass transfer processes in water supply, evaporation enthalpy, and salt rejection. Sequentially, subcooling, wettability, and geometry of the condensation side were discussed to improve water collection performance, which should be designed collaboratively with the evaporation side in a confined space. Finally, thermal recovery and electricity generation beyond water collection were also introduced, and some challenges still need to improve in the further for scalable and practical applications, including passive water collection rate, integrated system, and long-term issues. [ABSTRACT FROM AUTHOR]

This study investigates seasonal variations and influencing factors on the Deep Chlorophyll Maximum (DCM) in the Subtropical Front (STF) and Polar Front (PF) regions of the Indian Sector within the Southern Ocean, utilizing Bio-Argo floats data. Our analysis reveals distinct seasonal and regional patterns in salinity, temperature, and DCM dynamics. The STF region, characterized by warmer, saltier waters and a shallower Mixed Layer Depth (MLD), facilitates stronger stratification and nutrient retention, resulting in an enhanced DCM of 1.55 mg/m3. In contrast, the PF's colder, fresher waters exhibit deeper MLDs and reduced stratification, leading to lower mean DCM concentrations of 0.88 mg/m3. The depth of the DCM increased along this gradient, deepening from a median of 42 m at the STF to 78 m at the PF. We identify a robust correlation between DCM, Photosynthetically Active Radiation (PAR), and MLD, highlighting how environmental conditions profoundly influence DCM and its depth in these critical oceanic zones. This study shows that the DCM is present year-round in the STF, while it exhibits seasonal variability in the PF. [ABSTRACT FROM AUTHOR]

This study reports scale deformities in Cirrhinus mrigala, an economically significant Indian Major Carps, freshwater cyprinid in India. Specimens (160-257 mm standard length) with integumentary lesions and associated scale anomalies were obtained from a fish market in Chidambaram, Tamil Nadu. The scale deformities manifested as morphometric irregularities (shape and orientation) with disoriented scales exhibiting increased surface roughness. Notably, the lesions were encircled by these deformed scales. [ABSTRACT FROM AUTHOR]

Otolith features (length, width and weight) of 74 individuals of Anguilla anguilla collected from the Söke District of Aydın Province in Western Anatolia, Türkiye were studied for the first time to evaluate the level of asymmetry in the otolith features selected for this study. The asymmetry value of the otolith length was greater than that of otolith width and otolith weight. The asymmetry value of the three otolith features increased with an increase in the fish's length. The likely cause of asymmetry in the otolith parameters examined has been discussed in relation with the variability in growth provoked by ecological influence associated with the discrepancy in habitat setting and contaminants present in the Söke District of Aydın Province in Western Anatolia, Türkiye. [ABSTRACT FROM AUTHOR]

Baffin Bay is located between Greenland and several islands of the Canadian Arctic, providing a conduit for the downstream transport of ice and freshwater to the North Atlantic via Davis Strait. Using satellite observations from Sentinel‐1, the RADARSAT Constellation Mission, and CryoSat‐2, we estimated the sea ice export through Davis Strait and winter ice production in Baffin Bay from 2016 to 2022. The average annual ice export for this 6‐year period was 981 ± 193 × 103 km2 for area 816 ± 130 km3 for volume, and 653 ± 130 km3 for solid freshwater, all of which are considerably higher than previously reported estimates. The average winter ice area production upstream of Davis Strait was 758 × 103 km2 and the volume production was 589 km3 indicating that more than 80% of the ice exported out of Baffin Bay was produced locally. Compared to Fram Strait, sea ice fluxes through Davis Strait represent ∼59% of the volume and ∼111% of the area. Plain Language Summary: Baffin Bay is located between Greenland and several islands of the Canadian Arctic. Sea ice and freshwater is transported downstream to the North Atlantic through Davis Strait located at the southern end of Baffin Bay. Using the latest state‐of‐the‐art satellite observations we estimated the amount of sea ice and freshwater transported through Davis Strait in addition to the amount of ice produced in Baffin Bay from 2016 to 2022. Our ice transport and ice production estimates were considerably higher than previously reported estimates. Sea ice transport from Davis Strait represented 111% of area and 59% of the volume of the Fram Strait which is the Arctic's major ice export passageway. Key Points: High quality and consistent satellite derived estimates are provided for Baffin Bay sea ice exportApproximately 80% of the Baffin Bay ice exported via Davis Strait is locally producedAnnual sea ice export from Baffin Bay represents ∼59% of the volume flux and ∼111% of the area flux compared to Fram Strait [ABSTRACT FROM AUTHOR]

Karst subterranean estuaries within globally ubiquitous carbonate aquifers are coastal groundwater ecosystems that provide an essential water resource for human populations. To understand the drivers of salinization within a coastal aquifer in the Yucatan Peninsula (Mexico), we employed hydroacoustics in flooded caves to observe how oceanic and atmospheric events facilitate mixing between the meteoric lens (fresh‐brackish groundwater) and the saline groundwater on tidal and episodic timescales. Precipitation during Tropical Storm Carlotta increased the flow and salinity of the meteoric lens without evidence for vertical mixing across the halocline. We postulate that vertical migration of haloclines in the conduit relative to those within the rock matrix during precipitation creates lateral density gradients that drive mixing, and ultimately creates a brackish layer within the meteoric lens. These results provide a mechanistic explanation for vertical and lateral exchange in a coastal carbonate aquifer, which has implications for groundwater response to future climatic change. Plain Language Summary: Karst subterranean estuaries are regions of coastal aquifers where fresh and marine water mix within porous limestone bedrock that often contains extensive cave networks. These coastal aquifers are globally distributed and are a critical water resource increasingly stressed by sea‐level rise, climate change, and human activity. We installed acoustic devices and other sensors in the most extensively mapped underwater coastal cave on Earth to image and understand how rainfall‐derived fresh water and saltwater mix underground. We found that salinization of the low‐salinity portion of the aquifer following intense rainfall‐led mixing can temporarily render the water unsafe for drinking and useless for irrigation. We developed a conceptual model that describes how tides and rainfall‐driven changes cause saline water to drain laterally from the porous limestone bedrock and mix with fresher waters in open cave passages rather than by vertical mixing between water layers, as previous studies have suggested. Key Points: We present novel hydroacoustic observations of halocline dynamics within a karst subterranean estuary during Tropical Storm CarlottaIncreased precipitation resulted in increased salinity of the brackish layer of the aquifer despite stability of haloclinesDifferential vertical halocline movement in caves and the adjacent rock matrix drives lateral mixing between brackish and saline groundwater [ABSTRACT FROM AUTHOR]

Glossiphoniidae is a family of freshwater leeches, notable for their unique behaviour of parental care. After hatching, juveniles remain on the ventral side of their parent, where they receive protection and grow until they are ready to depart from the parent leech. The detachment of juveniles is a crucial stage for their development and independence from their parents, potentially influenced by various factors. To investigate these factors, ten parental individuals of Orientobdelloides siamensis were studied in the laboratory. Three to five days after copulation, all parental leeches deposited approximately 361.6±37.79 eggs on the substrate, which were covered until the end of the brooding period. Incubation of their single-egg cocoons took 7–9 days. Subsequently, the newborns attached to the ventral annulus of the parent by their caudal sucker. Seven to eleven days after hatching, the caudal sucker of juveniles expanded over the parent's annulus, indicating readiness to depart. The young leeches detached from the parental venter, moved to the substrate, and continued living under the ventral side of their parent. Finally, to determine the timing of juvenile detachment, the space availability beneath the parental venter and yolk depletion after hatching were analyzed. By observing morphological characteristics and behaviors, this study was able to investigate the interaction between these factors, and their correlation with juvenile detachment in O. siamensis. [ABSTRACT FROM AUTHOR]

This paper explores the production and reproduction of changing hydrosocial dynamics in South China since the construction of the Dongshen Water Supply Project (DWSP), an inter‐basin water transfer that supplies approximately 70% to 80% of freshwater from Mainland China to the Hong Kong Special Administrative Region. Drawing on the idea of the waterscape, I conceptualise the DWSP as an embodiment of power and socio‐environmental relations, encompassing a wide array of physical objects, institutions, and agencies. I show that, on one hand, the DWSP has expanded, improved, and renewed its physical forms over the past six decades and intertwined with various institutional and administrative changes that consolidate its role. On the other hand, the materialisation of the DWSP has been associated with diverging spatial configurations in both water‐exporting and water‐receiving areas. That has exacerbated disparities in water access, conservation responsibilities, and socioeconomic opportunities, perpetuating uneven waterscapes. This historical‐material examination of the DWSP provides a nuanced understanding of how power and social relations can manifest through water and how hydraulic infrastructure is intimately linked with development, governance, and inequalities over space and time. [ABSTRACT FROM AUTHOR]

The key locations of freshwater input driving Atlantic Meridional Overturning Circulation (AMOC) slowdown and their climate responses remain inconclusive. Using a state-of-the-art global climate model, we conduct freshwater hosing experiments to reexamine AMOC sensitivity and its climate impacts. The Irminger basin emerges as the most effective region for additional freshwater fluxes, causing the greatest AMOC weakening. While global temperature and precipitation responses are relatively homogeneous, subcontinental responses--especially in the northern mid-latitudes--are heterogeneous. At high latitudes, sea ice responses to freshwater fluxes and associated ice-albedo feedbacks determine temperature changes. In tropical and extratropical regions, temperature dynamics are shaped by atmospheric circulation and oceanic heat transport. Precipitation shows seasonal and regional variability due to altered surface turbulent heat flux and the southward movement of the Intertropical Convergence Zone (ITCZ). The widespread heterogeneity in climate extremes underscores the need to monitor freshwater release regions linked to AMOC slowdown. These findings hold vital implications for understanding paleoclimate and future AMOC impacts. [ABSTRACT FROM AUTHOR]

Reconstructing hydrological conditions of past warm periods, such as the Eocene 'hot house' provides empirical data to compare to state of the art climate models. However, reconstructing these changes in deep time is challenging, for example, given the complex interplay between evapotranspiration, precipitation and runoff. As a proxy for past changes in these hydrological systems, the dynamics of fresh water input into marginal seas can be used to identify the spatiotemporal distribution of riverine runoff. Elemental barium (Ba) and radiogenic strontium (87Sr) are, depending on the amount of runoff and the background geology of the catchment area, typically enriched in river waters in comparison to seawater and can thus be utilized to determine changes in riverine fresh water discharge. Here, we use barium to calcium ratios (Ba/Ca) and radiogenic strontium isotopes (87Sr/86Sr) measured in fossil bivalve shells to reconstruct patterns of fresh water input into the paleo North Sea during the early to middle Eocene. Our reconstruction shows the potential of Ba/Ca and 87Sr/86Sr to serve as proxies for riverine runoff and highlights the spatiotemporal complexity of Eocene hydrological conditions in western Europe. In particular, our results enable changes in riverine input along geological to perennial time scales for different coastal regions to be determined, revealing a steady influx of fresh water, but with distinct spatiotemporal differences. [ABSTRACT FROM AUTHOR]

Freshwater fungi exhibit a remarkable diversity and are commonly found on submerged wood, freshwater insects, herbaceous materials, sediments, leaves, foam, and living plants. Sordariomycetes in the Ascomycota is the most frequently reported group in freshwater environments. Three samples of submerged decaying wood and twigs samples were collected and examined during in this study from freshwater habitats in Yunnan and Sichuan provinces in China. Detailed morphological studies, complemented by phylogenetic analyses based on ITS, LSU, SSU, RPB2 and TEF1-α sequence data, revealed them to be three hitherto known species, namely Acrogenospora thailandica, Cancellidium cinereum and Chloridium humicola. Of these, Acrogenospora thailandica is a new geographical record for China. Chloridium humicola is also reported for the first time in China which enhances the geographical and host distribution of this species, providing new insights into its ecological preferences. Cancellidium cinereum is reported as an additional provincial record from China, contributing to our knowledge of its regional distribution. All three species, reported in their asexual state, are illustrated with detailed morphological descriptions and phylogenetic analyses. In addition, we also provide a new host record of the saprobic species Isthmolongispora quadricellularia in hyphomycetous asexual state on decaying wood for the first time in a terrestrial habitat. [ABSTRACT FROM AUTHOR]

Habitat transitions have shaped the evolutionary trajectory of many clades. Sea catfishes (Ariidae) have repeatedly undergone ecological transitions, including colonizing freshwaters from marine environments, leading to an adaptive radiation in Australia and New Guinea alongside non-radiating freshwater lineages elsewhere. Here, we generate and analyze one long-read reference genome and 66 short-read whole genome assemblies, in conjunction with genomic data for 54 additional species. We investigate how three major ecological transitions have shaped genomic variation among ariids over their ~ 50 million-year evolutionary history. Our results show that relatively younger freshwater lineages exhibit a higher incidence of positive selection than their more ancient marine counterparts. They also display a larger disparity in body shapes, a trend that correlates with a heightened occurrence of positive selection on genes associated with body size and elongation. Although positive selection in the Australia and New Guinea radiation does not stand out compared to non-radiating lineages overall, selection across the prolactin gene family during the marine-to-freshwater transition suggests that strong osmoregulatory adaptations may have facilitated their colonization and radiation. Our findings underscore the significant role of selection in shaping the genome and organismal traits in response to habitat shifts across macroevolutionary scales. Ecological transitions, like shifts between habitats, can shape genomic variation. By analyzing genomes from 66 sea catfish species, this study finds that younger freshwater lineages show more positive selection and body shape disparity, with prolactin gene adaptations likely aiding their colonization and radiation. [ABSTRACT FROM AUTHOR]

Green hydrogen production can be achieved through electrolysis of fresh water or the use of renewable energy to electrolyze seawater. However, due to the low activity and poor stability of oxygen evolution reaction catalysts, direct electrolysis of alkaline seawater faces significant challenges. Herein, The catalyst F‐CoFe(OH)‐CO3/NF with three‐dimensional nanosphere structure was prepared, The introduction of CO32− into the intermediate layer of CoFe hydroxide improves the corrosion resistance of alkaline electrolyte and the doping of F− is to design three‐dimensional layered nanostructures, increase the active site, and accelerate the diffusion of the electrolyte. By in situ Raman analysis, partial oxidation of CoFe hydroxide to CoFe (oxy)hydroxide as the active center can accelerating the adsorption of oxygen‐related intermediates. In 1 M KOH, it requires overpotentials of 210 mV and 251 mV to drive current densities of 10 and 100 mA cm−2, respectively. And it remained stable at the current density of 100 mA cm−2 for 120 h in 1 M KOH. F‐CoFe(OH)‐CO3/NF can also catalyzes the decomposition of electrolytic seawater. Compared with hydroxide, anion‐doped carbonate hydroxide is more efficient and stable in electrolyte solution, which is of great importance for the development of a new stable electrocatalyst for water decomposition. [ABSTRACT FROM AUTHOR]

Wheat can tolerate a mild water deficit, but prolonged drought causes a number of detrimental physiological changes resulting in a substantial decrease in productivity. The present study evaluates the potential of the natural plant growth regulator melatonin to alleviate the negative effects of moderate drought in two Bulgarian winter wheat cultivars at the early vegetative stage. Melatonin doses of 75 µM were root-supplemented 24 h before or after the stress period. The levels of several biometric parameters, osmolyte content and stress indicators as well as the expression of genes coding for key enzymes of the proline biosynthesis pathway were analyzed in leaves at the end of the drought stress and after two and four days of recovery. Applied alone, melatonin did not exert significant effects on most of the monitored parameters. Water deprivation negatively affected seedlings' fresh weight and water content and increased the stress markers and osmolyte levels. These were accompanied by a high accumulation of TaP5CS and TaP5CR transcripts coding for the enzymes Δ-pyrroline-5-carboxylate synthase and Δ-pyrroline-5-carboxylate reductase, respectively. The effect of melatonin in reducing drought stress was similar whether applied before or after exposure, though slightly more effective when used as a pre-treatment. [ABSTRACT FROM AUTHOR]

The coastal circulation around Southern Greenland transports fresh, buoyant water masses from the Arctic and Greenland Ice Sheet near regions of convection, sinking, and deep-water formation in the Irminger and Labrador Seas. Here, we track the pathways and fate of these fresh water masses by initializing synthetic particles in the East Greenland Coastal Current on the Southeast Greenland shelf and running them through altimetry-derived surface currents from 1993 to 2021. We report that the majority of waters (83%) remain on the shelf around the southern tip of Greenland. Variability in the shelf-basin exchange of the remaining particles closely follows the number of tip jet wind events on seasonal and interannual timescales. The probability of a particle exiting the shelf increases almost fivefold during a tip jet event. These results indicate that the number of tip jets is a close proxy of the shelf-basin exchange around Southern Greenland. [ABSTRACT FROM AUTHOR]

Our objective was to assess the effects of interactions between the native Percichthys trucha and both Salmo trutta and Oncorhynchus mykiss during the juvenile period. We conducted single and multipredator (conspecific and heterospecific) functional response (FR) experiments with Meridialaris chiloeensis as native prey and estimated the functional response ratio as a predator impact metric. Our results showed that all species have type II FR, with salmonids having a greater impact on prey than native fish. In multipredator experiments, O. mykiss had a greater negative impact on P. trucha than S. trutta. The individual feeding performance of P. trucha was better under conspecific than heterospecific conditions. This study shows that the vulnerability of juvenile P. trucha to salmonid competition could be a real threat in Patagonian lotic environments. [ABSTRACT FROM AUTHOR]

Adsorption-based direct air capture (DAC) of carbon dioxide, using chemisorbents like solid amines, has been widely recognized as a sustainable measure to contain atmospheric CO2 concentrations. However, the productivity and economic viability of DAC have been compromised by the high energy consumption for regenerating the adsorbents. Here, we show that by synergistically harvesting water and carbon dioxide from the atmosphere, we can regenerate the unit using in situ vapor purge at low energy and capital cost. The desorption of CO2 is substantially enhanced in the presence of concentrated water vapors at around 100 °C, concurrently producing 97.7% purity CO2 and fresh water without the use of vacuum pumps and steam boilers. Moreover, we demonstrate that the DAC prototype can also be powered by sunlight, which recovers 98% of the adsorbed CO2, with 20% less energy demand, enabling sustainable carbon capture from air in a real distributed manner. Direct air capture of CO2 suffers from high energy consumption. Here, the authors use co-harvested water as in situ vapor purge to regenerate the sorbents, achieving over 98% recovery of the adsorbed CO2, more than 20% reduction in energy penalty, and synergistic production of CO2 and water. [ABSTRACT FROM AUTHOR]

The pearlspot, Etroplus suratensis is a climate resilient cichlid fish that exhibits unusual adaptation to salinity. The fish is able to complete full life cycle in diverse salinity habitats ranging from fresh water to marine environments. High-quality primary and phased genome assemblies were generated for pearlspot fish using PacBio HiFi and Arima HiC sequencing technologies, for the first time. The primary assembly is highly contiguous with contig N50 length of 36 Mb. The final assembly is of 1.247 Gb with N50 length of 51.57 Mb and 98% of the genome length anchored to 24 chromosomes. The genome was assessed to be 99.9% complete based on BUSCO evaluation and was predicted to contain 52.96% repeat elements. We have predicted 27,192 protein encoding genes, of which 21,580 were functionally annotated. The genome offers an invaluable resource to understand adaptation of pearlspot fish to diverse salinity habitats. [ABSTRACT FROM AUTHOR]

Small island communities often rely on groundwater as their primary source of fresh water. However, the limited land area and high proportion of coastal zones pose unique challenges to groundwater management. A detailed understanding of the subsurface structure can provide valuable insights into aquifer structure, groundwater vulnerability, saltwater intrusion, and the location of water resources. These insights can guide groundwater management strategies, for example, pollution regulation, promotion of sustainable agriculture, establishment of coastal buffer zones, and re‐naturalization of land cover. Ordinarily, structural characterization relies on geological mapping and boreholes, however, such approaches can have insufficient spatial resolution to aid groundwater management. In this study, transient electromagnetic (TEM) methods are used to map the subsurface of a small, 13.2 km2, Danish Island. The approach successfully identified two previously unknown paleochannels, where the interface between Quaternary aquifer units and an underlying Paleogene Clay aquiclude had maximum depths of 100 and 160 m below sea level. Before this, the interface was assumed to be 15 to 25 m below sea level: therefore, these paleochannels present substantial potential groundwater resources. Resolving geological heterogeneity within the Quaternary deposits was less successful and future work will focus on addressing these limitations. Nonetheless, in several locations, evidence of saltwater intrusion was observed within the Quaternary units. This work demonstrates how TEM mapping can identify water resources, define aquifer boundaries, and aid water management decisions. Such approaches could be applied in other areas, particularly small islands, where similar groundwater challenges exist. [ABSTRACT FROM AUTHOR]

Syngnathidae are a charismatic family of teleost fishes, represented by seahorses, seadragons, and pipefishes. Syngnathidae are mainly composed of marine species, but about 30 species of pipefishes inhabit freshwater insular environments of the Indo‐Pacific realm. Recent research has shown that some freshwater pipefish species are amphidromous and exhibit high intraspecific divergences across their distribution range, like Microphis brachyurus (Bleeker, 1854) distributed from Sri Lanka to French Polynesia and Microphis retzii (Bleeker, 1856) distributed from Taiwan to Indonesia. In this study, we used the mitochondrial cytochrome oxidase I (COI) partial gene of 91 specimens of M. brachyurus and 30 specimens of M. retzii from localities representative of their respective distribution area to improve knowledge on the population structure of these two widespread species. Genetic species delimitation and phylogeographic analyses were combined to explore spatial patterns of genetic diversity across the distribution ranges of the two species. We have highlighted deep genetic structuring within the two species and relate these results to various biotic and abiotic factors. For M. brachyurus, the population in Polynesia is distinct from those in the West Pacific, suggesting its distinctiveness and recognition as an evolutionary significant unit (ESU). For M. retzii, three lineages are delimited in its range distribution, suggesting the existence of two distinct species in Southeast Asia (Bali/Java/Lombok and China/Taiwan). Pipefish species are particularly vulnerable to anthropogenic pressures (inherent to Syngnathidae and insular environments). The present results, revising species delimitation and geographic distribution, will help implement effective conservation and management measures. [ABSTRACT FROM AUTHOR]

\nHighlightsIn this paper, we used the polyphasic approach combining 16S rRNA gene phylogenies, identity (p-distance), 16S-23S ITS secondary structures, and morphological and habitat analyses to describe two new genera of Leptolyngbyaceae, Pseudoleptolynbgya G.S. Hentschke gen. nov. (based on LEGE 16533 and LEGE 16651) and Leptolyngbyopsis G.S. Hentschke gen. nov. (based on LEGE 16524). These strains were sampled from freshwater environments at Figueira da Foz, Monchique and Coimbra, Portugal. Both genera are morphologically and ecologically identical to Leptolyngbya and can only be distinguished from it by molecular analyses. Based on morphological and ITS secondary structure analyses we describe two species of Pseudoleptolyngbya, P. figueirensis and P. monchiquensis. P. figueirensis differs from P. monchiquensis by the denser arrangement of the trichomes, the presence of firm sheaths, the common formation of shorter trichomes (up to 30 cells), and the olive or yellowish-green cell content, which is darker in P. monchiquensis. Moreover, the macroscopic appearance of P. figueirensis is a dense brownish mat, while P. monchiquensis is less dense and reddish. 16S rRNA gene sequences of Arthronema africanum CCALA020 are > 99% identical to Leptolyngbya boryana PCC6306, so we transfer A. africanum to Leptolyngbya, as L. africanoidea. Pseudoleptolyngbya gen. nov. and Leptolyngbyopsis gen. nov. are described.Arthronema is placed in synonymy with Leptolyngbya.Pseudoleptolyngbya gen. nov. and Leptolyngbyopsis gen. nov. are described.Arthronema is placed in synonymy with Leptolyngbya. [ABSTRACT FROM AUTHOR]

The problem for residents in island and coastal areas is the lack of fresh water, especially during the dry season. In the dry season, there is abundant potential for solar energy utilization. This potential can be utilized as an energy source for distilling seawater into fresh water using solar still technology. Solar still performance is influenced by the evaporation and condensation processes. Several researchers have made efforts to increase evaporation, such as enhancing the heat absorption of absorber plates and preheating seawater. This research aims to apply initial heating to seawater to enhance the evaporation process. The initial heating of seawater is obtained from heat absorption in the walls, which function as a cooling medium. Thus, this research aims to investigate the use of cooling water on the walls as input water to enhance the performance of double-slope solar stills. The research was carried out experimentally and theoretically. Research on the performance of a double-slope solar still utilizes wall cooling water as input water (SSDS.WCW.HC) compared to wall water cooling (SSDS.WCW). The research yielded an average daily condensate water productivity using SSDS.WCW.HC experimentally of 3.48 kg/10-hours and theoretically of 3.56 kg/10-hours, which is higher compared to SSDS.WCW experimentally of 3.16 kg/10-hours and theoretically of 3.27 kg/10-hours. The average daily energy efficiency using SSDS.WCW.HC experimentally is 53.77 % and theoretically 54.83 % higher compared to SSDS.WCW, which is 48.87 % experimentally and 49.81 % theoretically. The highest daily average exergy efficiency using SSDS.WCW.HC was 6.44 %, compared to 5.33 % for SSDS.WCW. [ABSTRACT FROM AUTHOR]

Understanding the palaeoenvironment of the Loess Plateau plays a key role in the researches about influences caused by the Tibetan Plateau uplift and the formation of the East Asia Monsoon (EAM). The Longxi area of the Gansu Province, northwestern China, is an ideal area to study such influences because of its unique geographical location within the transition zone among the EAM region, inland arid areas and the northeastern Tibetan Plateau. Here, we present ostracods from a borehole in the Longxi area, as ostracods are one of the few micropalaeontological proxies available in freshwater sediments. The studied ostracods were assigned to 13 species of 10 genera and 9 indeterminate taxa and reported for the first time from the Linxia Formation in the studied area. The ostracod assemblage is composed entirely of non-marine taxa, including species of Ilyocypris, Cypris, Cyprinotus, Heterocypris, Eucypris, Potamocypris, Zonocypris, Candona, Pseudocandona and Leucocythere. Ostracod biostratigraphy indicates that the Linxia Formation should be Pliocene in age. Palaeoenvironmental analysis of the studied ostracod assemblages suggests that there was a permanent freshwater lake with some temporary ponds in the studied area of the Loess Plateau during the Pliocene, which shows the influences of the East Asian Summer Monsoon during the Pliocene. [ABSTRACT FROM AUTHOR]

Our work provides a checklist of freshwater decapods (Brachyura and Caridea) from the Parnaíba river basin, Brazil, based on field collections carried out between 2018 and 2020. Eight species were collected at 30 sampling sites in the main river channels, streams, and ponds throughout the upper, middle, and lower regions of the Parnaíba river basin. The species of shrimp reported herein are Atya gabonensis (Gibiel, 1875) (Atyidae), Macrobrachium amazonicum (Heller, 1862), Macrobrachium brasiliense (Heller, 1862), Macrobrachium jelskii (Miers, 1778), and Macrobrachium olfersii (Wiegmann, 1836) (Palaemonidae), while crab species reported are Goyazana castelnaui (H. Milne-Edwards, 1853), Sylviocarcinus pictus (H. Milne-Edwards, 1853) (Trichodactylidae), and Kingsleya parnaiba Pralon, Pinheiro & Santana, 2020 (Pseudothelphusidae). The record of Macrobrachium brasiliense is the first for the Parnaíba river basin. The knowledge of the diversity of freshwater decapod fauna can contribute to the conservation of species and their habitats. [ABSTRACT FROM AUTHOR]

Freshwater from the Arctic participates in the globally important Atlantic Meridional Overturning Circulation (AMOC). We use high‐resolution, in situ observations of dissolved organic matter (DOM) fluorescence to trace the origins of freshwater and organic carbon in the densest component of the AMOC, namely Denmark Strait Overflow Water (DSOW). We find a distinct terrestrial DOM signal in DSOW and trace it upstream to the Siberian shelves in the Arctic Ocean. This implies a riverine origin of freshwater in DSOW. We estimate that the Siberian Shelf water contribution constitutes approximately 1% of DSOW. Ocean circulation modeling confirms the inferred pathway and highlights Denmark Strait as an important location for the entrainment of the riverine signal into DSOW. Our proposed method can be deployed on a range of observing systems to elucidate freshwater dispersion across the Arctic and subarctic, thereby contributing to the broader discussion on freshwater impacts and organic carbon sequestration in the AMOC. [ABSTRACT FROM AUTHOR]

Water is the main actor of a summer school dedicated to heritage and environment, realized in navigation, by a community of international and multidisciplinary students and teachers, and dedicated to an in-depth investigation of the seas of the former Yugoslavia. The narrow spaces of a small wooden gulet acted as a floating classroom, meeting-point, and hostel, while the limited spaces and fresh water available were shared among all participants. Sharing the scarce spaces and limited water resources has represented a metaphor of reciprocal interdependence, and it was the main educational texture of the summer school on board. [ABSTRACT FROM AUTHOR]

We investigate how the Helobdella sp. freshwater leeches capture and consume Lumbriculus variegatus blackworms despite the blackworm's ultrafast helical swimming escape reflex and ability to form large tangled "blobs." We describe a spiral "entombment" predation strategy, where Helobdellid leeches latch onto blackworms with their anterior sucker and envelop them in a spiral cocoon. Quantitative analysis shows that larger leeches succeed more often in entombing prey, while longer worms tend to escape. The rate of spiral contraction correlates with entombment outcomes, with slower rates associated with success. These insights highlight the complex interactions between predator and prey in freshwater ecosystems, providing new perspectives on ecological adaptability and predator-prey dynamics. [ABSTRACT FROM AUTHOR]

Instances of convergent or parallel evolution provide a potent model system for exploring contingency and determinism in evolutionary biology. Likewise, the multiple, independent habitat transitions from saltwater to freshwater biomes offer opportunities for studying convergent evolution within and among different vertebrate lineages. For example, stingrays have invaded freshwater habitats multiple times across different continents, sometimes even several times within the same clade (e.g. Dasyatidae). We evaluated the frequency of saltwater–freshwater invasions in stingrays, compared ecological and phenotypic diversification among freshwater and saltwater lineages, and assessed the degree of convergence among freshwater species. Despite not being morphologically distinct from saltwater stingrays, freshwater stingrays do expand the margins of stingray morphological diversity. According to our data, trophic specialists occupied non-overlapping regions of morphospace, with piscivores and molluscivores being distinct from other diet guilds. Freshwater stingrays as a group did not strongly converge morphologically, neither did freshwater rays from different lineages, which shared similar niches. These findings could be explained by there not being enough time for convergence to occur among more ancient and more recent freshwater lineages. Alternatively, the different ancestral bauplans of various freshwater ray lineages and weak selection on optimal phenotypes could promote contingency in the form of evolution along paths of least resistance. [ABSTRACT FROM AUTHOR]

Niche and dispersal‐based processes govern freshwater communities, such as aquatic insects, shaping their distribution and establishment in the environment. So, we aimed to address the relative influence of niche and dispersal‐based processes on Odonata diversity in Amazonian freshwater systems, and the influence of species dispersal functional traits on their longitudinal and latitudinal ranges.We used the Dispersal‐Niche Continuum Index (DNCI) to test (i) regions more distant would present a prevalence of dispersal‐based processes, and (ii) different patterns would come from the two Odonata suborders; and by applying generalised linear models, we tested (iii) dispersal‐related functional traits from the suborders would influence latitudinal and longitudinal midpoints of the species.We found that more distant regions had lower values of pairwise Dispersal–Niche Continuum, mainly for Zygoptera, corroborating our first hypothesis. Moreover, Zygoptera also presented the lowest absolute values of Dispersal–Niche Continuum and Anisoptera presented a joint influence of niche and dispersal‐based processes, agreeing with our second hypothesis. Only Zygoptera presented a significant association between dispersal functional traits and longitudinal midpoints, corroborating our third hypothesis.Our results indicated a prevalence of dispersal‐related processes for Zygoptera, which can be explained by massive geographical barriers, such as the rivers, and their narrow physiological and ecological tolerance. Moreover, dispersal‐related traits demonstrated significant influence on longitudinal midpoints of Zygoptera, a scenario that the presence of the rivers may explain. A better understanding of the prevalent predictors of the species and how their dispersal ability governs their distribution has conservational implications. [ABSTRACT FROM AUTHOR]

Anadromous migration of salmonid fish has been extensively studied, primarily focusing on the dichotomous framework of anadromy and residency. However, there remains a limited understanding of intermediate migratory behaviors within the anadromous framework. Our study aimed to classify the lifetime migration patterns of the anadromous white-spotted charr Salvelinus leucomaenis within and among populations using otolith annuli and Sr:Ca ratios. Initially, the migratory histories of anadromous charr were divided into two stages: "virgin sea-run stage" and "veteran sea-run stage". The former was further categorized into three types: ocean entry at age ≥1+ years old, early descending, and brackish use. The latter was grouped into four types: annual migrants, frequent migrants, retired migrants, and ocean residents. We found that the proportion of migration patterns varied among rivers, with multiple patterns coexisting within the same river. Migration patterns typically involving 1–5 years spent in freshwater rivers followed by annual oceanic migrations were the most abundant, although diverse patterns were also observed. In the virgin sea-run stage, some individuals experienced the ocean at age 0+ years or brackish environments before their first sea entry. In the veteran sea-run stage, we found individuals who had resided in either the ocean or rivers for over a year. Retired migrants, characterized by stopping oceanic migration at a certain age and subsequently spending time in rivers, were exclusive to southern rivers. Conversely, ocean residents who spend one or more years in the ocean were more frequent in northern regions. Consequently, the lifetime migration patterns of anadromous white-spotted charr may exhibit stronger ocean dependency at higher latitudes. The implications of this study highlight the complexity and flexibility of migratory behaviors within and among white-spotted charr populations. [ABSTRACT FROM AUTHOR]

Limited water availability, population growth, and increasing water demand have resulted in freshwater crises in many countries, including China. In this paper, the water resource‐carrying capacity (WRCC) model simulated the trajectory of China's various systems, representing interactions among humans, water resources, and economics, among others. The results indicated that, at the national level, 700 billion m3 of available freshwater could support population sizes of 2.12, 1.96, and 1.85 billion, along with economic sizes of $40.65, $34.08, and $29.21 trillion, under high‐, moderate‐, and low‐development scenarios, respectively. And it also showed the population and economic size of each province across China under high‐, moderate‐, and low‐development scenarios. This study's WRCC‐based simulations can provide guidance for future policies related to water, population, and economics. Overall, contributions of this study include (1) a quantitative model related to freshwater security and water policies; (2) the model narratives that paint a better picture of China's future water security and socioeconomic development; (3) the conclusion that it is conducive to adjust water use rigid constraints with water policies; (4) an understanding that it is more intuitive to use population size and economic scale instead of dimensionless scores to characterize the state of WRCC. The WRCC model is instructive for the other counties or regions. [ABSTRACT FROM AUTHOR]