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In this paper, the feasibility of managed aquifer recharge (MAR) for southwestern Kansas was investigated. Multiple sources of water for MAR were investigated, including rainfall-runoff from fields, use of low-flow or ephemeral rivers and streams, and use of a large regional river. Use of the Arkansas River was found to be the most viable source of water. Construction of infiltration basins in existing sand mines was found to be the best MAR alternative in this region. The requirement for the reclamation of sand mines set out by the State of Kansas fits the requirements of infiltration basins, and there exists a local ditch system that can convey Arkansas River flows to the basins with little need of new construction. The salinity of the Arkansas River is of concern. The negative impact of this could be reduced by selecting salt-tolerant crops. This investigation is relevant throughout the State of Kansas, leading to the possibility that another region would have more suitable conditions. [ABSTRACT FROM AUTHOR]

Saltwater intrusion is a common issue in the Yangtze River estuary (YRE), significantly affecting the nearshore ecological environment and human activities. Using 20 years of runoff data, a high-resolution Finite-Volume Coastal Ocean Model (FVCOM) is constructed to simulate the lower reaches and estuary of the Yangtze River. This model is employed to analyze full-depth current and salinity characteristics and to explore the influence of factors such as runoff, wind, tides, and riverbank morphology on saltwater intrusion in the YRE. The model's accuracy is validated by comparing its output with current speed and salinity observations and comparing long-term salinity variations with reanalysis data. The comparison shows that the model well reproduces the saltwater intrusion in the YRE. Over the long term, the salinity pattern exhibits a "high–low–high" variation. Analyzing the vertical structure of the intrusion, it is observed that during summer, surface waters are heated, resulting in stronger stratification, weaker mixing, and a more pronounced saltwater intrusion in the YRE. Using power spectrum and correlation analyses, runoff is identified as the factor having the greatest impact on saltwater intrusion, followed by meridional wind and changes in riverbank morphology. This study of the variations in long-term saltwater intrusion has important reference value for the protection of freshwater resources in the YRE. [ABSTRACT FROM AUTHOR]

Rapidly capturing the spatial distribution of soil salinity plays important roles in saline soils' management. Existing studies mostly focus on the macroscopic distribution of soil-salinity changes, lacking effective methods to detect the structure of micro-regional areas of soil-salinity anomalies. To overcome this problem, this study proposes a 3D Soil-Salinity Anomaly Structure Extraction (3D-SSAS) methodology to discover soil-salinity anomalies and step forward in revealing the irregular 3D structure of soil-anomaly salinity areas from limited sampling points. We first interpolate the sampling points to soil voxels using 3D EBK. A novel concept, the Local Anomaly Index (LAI), is developed to identify the candidate soil-salinity anomalies with the greatest amplitude of change. By performing differential calculations on the LAI sequence to determine the threshold, the anomaly candidates are selected. Finally, we adopt 3D DBSCAN to construct anomalous candidates as a 3D soil-salinity anomaly structure. The experimental results from the Yellow River Delta data set show that 3D-SSAS can effectively identify the 3D structure of salinity-anomaly areas, which are highly correlated with the geographical distribution mechanism of soil salinity. This study provides a novel method for soil science, which is conducive to further research on the complex variation process of soil salinity's spatial distribution. [ABSTRACT FROM AUTHOR]

Invasions of non-native species have been occurring across the globe, mostly due to human activities or climate change. Although most introduced species fail to expand or have slight impact on their new ecosystems, the large number of true invasive species has led to serious economic and ecological problems. Knowledge of the fundamental drivers shaping the current distribution and abundance of invasive species of barnacles of the genus Amphibalanus Pitombo, 2004 in Iraq are still poorly understood. We collected samples of barnacles from 21 sites from the lower reaches of the Shatt Al-Arab with salinities of 20–24 ppt to the upper part of the Shatt Al-Arab, and northwest to the Al-Hammar marshes and the Euphrates River with salinities of 0.9–2.8 ppt. Amphibalanus amphitrite  (Darwin, 1854) was widely distributed, occurring at most sites. With the exception of a few sites close to the mouth of the Shatt Al-Arab, A. improvisus  (Darwin, 1854) was restricted to sites with salinities of 22–37 ppt. Amphibalanus subalbidus  (Henry, 1973) had an oligohaline distribution, occurring in moderately saline water. Redundancy analysis (RDA) revealed that the spatial distribution and abundance of all three species were influenced by salinity and temperature. Overall, our results confirm the importance of mapping the spatial distribution and abundance of invasive species in order to assess and manage the risks these species pose to native ecosystems. [ABSTRACT FROM AUTHOR]

Ion‐selective nanochannel membranes assembled from two‐dimensional (2D) nanosheets hold immense promise for power conversion using salinity gradient. However, they face challenges stemming from insufficient surface charge density, which impairs both permselectivity and durability. Herein, we present a novel vacancy‐engineered, oxygen‐deficient NiCo layered double hydroxide (NiCoLDH)/cellulose nanofibers‐wrapped carbon nanotubes (VOLDH/CNF‐CNT) composite membrane. This membrane, featuring abundant angstrom‐scale, cation‐selective nanochannels, is designed and fabricated through a synergistic combination of vacancy engineering and interfacial super‐assembly. The composite membrane shows interlayer free‐spacing of ~3.62 Å, which validates the membrane size exclusion selectivity. This strategy, validated by DFT calculations and experimental data, improves hydrophilicity and surface charge density, leading to the strong interaction with K+ ions to benefit the low ion transport resistance and exceptional charge selectivity. When employed in an artificial river water|seawater salinity gradient power generator, it delivers a high‐power density of 5.35 W/m2 with long‐term durability (20,000s), which is almost 400 % higher than that of the pristine NiCoLDH membrane. Furthermore, it displays both pH‐ and temperature‐sensitive ion transport behavior, offering additional opportunities for optimization. This work establishes a basis for high‐performance salinity gradient power conversion and underscores the potential of vacancy engineering and super‐assembly in customizing 2D nanomaterials for diverse advanced nanofluidic energy devices. [ABSTRACT FROM AUTHOR]

Copyright of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Ürünleri Dergisi is the property of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Urunleri Dergisi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tikrit Journal of Engineering Sciences is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduction: Salinity of water and soil resources is one of the most basic agricultural problems, especially in arid and semi-arid regions. Identifying and domesticating salinity-resistant plant (halophytes) species with economic value is an important strategy for these regions. Materials and methods: This research aimed to investigate the amount of elements and the quality of fodder in several Salicornia species under the influence of water salinity in a factorial experiment with a completely randomized design in pot culture conditions in Bojnourd (North Khorasan province) in 2018. Irrigation treatment was applied at two levels (brackish water and normal water), and Salicornia species treatment included four species (Salicornia persica, S. sinus persica, S. europaea, and S. bigelovii) and Salicornia var Markazi. The source of salty water was the Kal-Shoor river in Esfrain and the source of normal water was the well located in Research and Education of Agriculture and Natural Resurces Center in Bojnourd. Due to the high salinity of Kal-Shoor river, normal water was used to adjust the salinity to the treatment limit of 45 dSm-1. To produce seedlings, Salicornia seeds were planted in plastic combs for seedling production in April 2018. After 60 days, seedlings (10-15 cm) were transferred to pots. The irrigation circuit varied in different growth stages according to weather conditions, and irrigation was done by the weight method with the 80% moisture index of the pots. Results and discussion: The results showed that the amount of nitrogen, phosphorus, potassium, magnesium, sodium and chlorine increased with the increase in irrigation water salinity in all species. The highest accumulations of sodium (11%) and chlorine (23.5%) were observed in S. sinus persica and the lowest amount of sodium (8.6%) and chlorine (21%) were observed in S. persica. Among the Salicornia species, the lowest amount of elements is related to potassium and phosphorus ions, which is mostly due to the limitation of the absorption of these elements under the influence of sodium ions, and as mentioned in the sources, the process of absorption of these elements increases gradually with the growth stages. Maintaining a more negative potential of the membrane is an important factor for salinity tolerance, considering that in saline soils, chlorine and sodium are the most common solutes, the absorption of sodium and chlorine ions is important for regulating osmotic pressure and cytoplasmic concentration. In this experiment, in both irrigation treatments, the most elements in all species were related to chlorine and sodium ions. Based on the measurement of quality variables of fodder, the percentages of protein, crude fat, and ash in salty water treatment were higher than those in normal water. The highest percentage of crude fat (1.32%) in S. var. Markazi was affected by saltwater treatment, which was significantly different from the other species. The highest percentages of protein in S. bigelovii and S. europaea under the influence of saltwater treatment were 6.06% and 6.31%, respectively, which were significantly different from the other species. The highest amounts of ash belonged to S. europaea (63%) and S. bigelovii (62%) in saltwater treatment, and S. sinus persica contained the least ash (49%) in normal water treatment. Although the increase in protein increases the quality of fodder, the increase in the amount of ash and crude fat causes limitations in animal nutrition and digestibility. Therefore, the increase of water salinity has a negative effect on the quality of fodder. Conclusion: Brackish water treatment increased the amount of ash in all species to different proportions, which is a limiting factor for the pure consumption of salicornia in animal feed. Therefore, the relative reduction of water salinity and the selection of suitable species are effective in increasing the quality of fodder.On the other hand, the great ability of Salicornia species to absorb and store salts in their aerial parts provides the basis for the exploitation of their vegetative organs for the production of vegetable salt. Moreover, it is economically important along with other applications of Salicornia (production of fodder, oil, medicines, and protection). [ABSTRACT FROM AUTHOR]

Estuaries have strong physicochemical gradients that lead to complex variability and often high rates of biogeochemical processes, and they are also often impacted by humans. Yet, our understanding of estuarine biogeochemistry remains skewed towards temperate latitudes. We examined seasonal and spatial variability in dissolved organic matter (DOM) and nutrients along a partly eutrophic, agricultural–urban estuary system in Southeast Asia: the Johor River and the East Johor Strait. Dissolved organic carbon (DOC) and coloured DOM (CDOM) showed non-conservative mixing, indicating significant DOM inputs along the estuary. The CDOM spectral slopes and CDOM : DOC ratios suggest that terrigenous, soil-derived DOM dominates along the Johor River, while phytoplankton production and microbial recycling are important DOM sources in the Johor Strait. CDOM properties were not unambiguous source indicators in the eutrophic Johor Strait, which is likely due to heterotrophic CDOM production. Nitrate concentrations showed conservative mixing, while nitrite concentrations peaked at intermediate salinities of 10–25. Ammonium concentrations decreased with salinity in the Johor River but increased up to 50 µ mol L -1 in the Johor Strait, often dominating the dissolved inorganic nitrogen (DIN) pool. Phosphate concentrations were low (<0.5 µ mol L -1) throughout the Johor River but increased in the Johor Strait, where DIN : phosphate ratios were typically ≥ 16 : 1. This suggests that the Johor Strait may experience phosphorus limitation and that internal recycling is likely important for maintaining high nutrient concentrations in the Johor Strait. Overall, our results indicate that the Johor River and Johor Strait are clearly not part of the same estuarine mixing continuum and that nutrient recycling processes must be quantified to understand nutrient dynamics in the Johor Strait. Moreover, our results highlight the need for better techniques for DOM source tracing in eutrophic estuaries. [ABSTRACT FROM AUTHOR]

Salt has major importance as a basic necessity in households, feedstock for various kinds of industry, and a means of fortification to prevent diseases attributed to iodine deficiency. However, the amount of salt produced in Indonesia has yet to meet the national demand, hence warranting the necessity of salt yield improvement. This research set out to evaluate the hydrological and climatological states of the coastal area of Gunungkidul Regency for potential salt farms. The hydrological analysis identified underground rivers, springs, and surface rivers emptying into the study area, whereas the hydrochemical analysis observed major elements of seawater and salinity and determined the effects of hydrological characteristics on seawater. The climatological evaluation involved analyzing rain, temperature, humidity, and daily wind data from 1979-2013. All of these details were matched against the suitability parameters for salt farms. The results showed that the hydrological and geological conditions were closely related and that the underground rivers, springs, and surface rivers decreased salinity and sodium and chloride contents of seawater. Based on salinity levels, several beaches were highly suitable (S1) for salt farms, but climatologically, the study area was slightly suitable (S3) and suitable (S2) for this purpose. [ABSTRACT FROM AUTHOR]

In Australia, salinity is a significant issue plaguing freshwater systems, especially in catchments modified by mining activities. River salinity varies in composition from changes in aquifer lithology, natural salt deposits and salt accumulation due to land altering activities (e.g., mining and agriculture). Complex salinity matrixes arise when different salinity sources and compositions are diluted into freshwater systems. Monitoring waterway salinity and characterizing salinity matrixes is vital to mitigating adverse impacts on agriculture, drinking water supplies and ecosystem health. However, to date, few studies have focused on characterizing salinity in freshwater systems based on source. In this paper, case studies drawn from the Burdekin and Fitzroy catchments, Queensland, are characterized for different salinities associated with mining and natural geogenic mineralization. Salinity coefficients (ke), a ratio of total dissolved solids (TDS in mg/L) to electrical conductivity (EC in µS /cm), are utilized to identify variations in salinity composition. Long-term water quality data (1964-2023) is retrieved from the Queensland Government's water monitoring program. Findings indicate that mining activities in both catchments have a significant influence on freshwater salinity matrixes, driving lower ke values (0.561-0.587). A novel method for analyzing long-term ke data is introduced, utilizing the slope (m) of ke in cumulative distribution plots. Significant variations in slope in the Fitzroy (m: 9.6, 5.3, 2.3) and in the Burdekin River (m: 8.9, 1.6, 1.0, 0.7) reveal influences on local mineralization and industry, not readily evident when only considering average ke. This study demonstrates that utilizing known geochemical, EC and TDS relationships and ke is an effective preliminary method for identifying salinity complexity, composition and source. Salinity in the Fitzroy catchment surpasses aquatic toxicity thresholds (EC50: 2410 µS/cm), revealing significant risks to freshwater aquatic species. [ABSTRACT FROM AUTHOR]

Collaborations between archeologists and aquatic scientists are driving forward a whole new subdiscipline of methods to document and understand environmental change. Climate change, food webs, El Niño La Niña oscillations, and alterations to biotic factors such as salinity and stream flow have all been studied via aquatic archeological material. Much of this research is conducted on shell middens, the archeological materials they contain, and substrates they are deposited in. This article provides a primer on the formation of shell middens, procedures of midden archeological excavation, and the recent advances in aquatic environmental change research from analyzing archeological material collected from middens. [ABSTRACT FROM AUTHOR]

Flow influences major ion concentrations in river water, therefore, it seems that it can differentiate ion concentrations in mountain rivers in different hydrological years. This study aimed to determine the impact of flow on the major ion concentrations in the Carpathian Raba River above and below the Dobczyce Reservoir (southern Poland) in hydrologically dry (HD), average (HA), and wet (HW) years (period April–October) in the period 2010–2017. In the river above the reservoir, the flow negatively affected the concentrations of most major ions under all hydrological conditions, which resulted in their significant differences between (1) the studied hydrological years (except for SO42−)–higher in the HD years than in the HA or HW years–and (2) seasons–higher Mg2+, Na+, K+, Cl−, and SO42− concentrations (mainly point sources of pollution) were identified in summer or autumn than in spring in the HD and HA years. The dam reservoir strongly modified the ion concentrations in the downstream river. It significantly decreased all major ion concentrations only in the HD years, when they were high in the upstream river, and Ca2+, Mg2+, or HCO3− concentrations in all the studied hydrological years. There, the ion concentrations were not related to the flow that resulted in their insignificant differences between the studied hydrological years (with the exception of HCO3−, Ca2+, and Cl−) and different seasonal changes to those in the river above the dam. The obtained results allow for predicting conditions favouring an increase in the salinity of mountain river waters; therefore, they are important for appropriate management and water use opportunities. [ABSTRACT FROM AUTHOR]

In their recent paper, Williams et al. (2022) evaluated salinity management in the Murray-Darling Basin (MDB) as 'unsustainable', and a risk to water availability and quality in the Basin. However, this evaluation was weakened first by a failure to analyse the Basin salinity strategies of the last thirty-five years, noting that these have led to Basin salinity target being met since 2010; and second to not providing Basin-specific data to support their evaluation. Contrary to Williams et al. comments, existing evidence indicates that infrastructure intended to improve water use efficiency (e.g. salt leaching, salt disposal basins) will generally reduce stream salinity. The requirement for a leaching efficiency means that there is a lower limit to water use efficiency improvements, but this is unlikely itself to be a major risk. We agree that the changes that have occurred over the last twenty years would warrant a review of salt storage options in the MDB that better matches future needs. [ABSTRACT FROM AUTHOR]

The Shatt Al-Arab estuary is the lifeline of the Basrah city, as it is the source of water for various uses of irrigation, industry, agriculture and human use, in addition to being the navigational passage towards the Arabian Gulf throughout history. Nowadays, the estuary suffers from the deterioration of its water quality due to the increase in salinity values as a result of the intrusion of salinity from the Arabian Gulf due to the lack of freshwater flows from the Tigris and Euphrates rivers. To reduce the risks of water quality deterioration and the lack of natural solutions represented in the provision of freshwater, the idea of building an artificial structure to narrow the channel came to give the ability to resist the impact of the tide and the intrusion of marine salinity. Two hypothetical sites were chosen to build the structure: i.e. in Dweeb and Faw sites, to test the feasibility of this artificial estuary structure. A one-dimensional mathematical model was adopted, which is the Mike 11 software package. The model was run according to a set of scenarios using the critical water discharge values of 10 and 20 m3/s. The results showed through simulation of the model for a period of six months that the structure is useful on improving the water quality by reducing salinity in the river, in addition, there is a delay in the time of arrival of the intrusion of salts. [ABSTRACT FROM AUTHOR]

Achieving the Sustainable Development Goals (SDGs) is challenging given the complex interactions between different SDGs and their spillover effects. We developed a system dynamics model—the Local Environmental and Socio‐Economic Model (LESEM)—to analyze and quantify context‐based SDG interactions at the local scale using a participatory model co‐design process with local stakeholders. The LESEM was developed for the Goulburn‐Murray Irrigation District in Victoria, Australia, to assist policymakers in analyzing local issues with a more integrated and holistic approach to sustainable development at the local scale. The process of participatory systems dynamics modeling facilitates integrated and strategic decision‐making and can help local policymakers identify and quantify potential trade‐offs and synergies that benefit multiple SDGs, which eventually leads local communities toward sustainability. We present an illustrative application of the model that quantifies SDG interactions across four high‐priority SDGs, namely clean water and sanitation (SDG 6), zero hunger (SDG 2), economic growth (SDG 8), and life on land (SDG 15). We illustrate the use of the model in assessing key SDG indicator trajectories under a business‐as‐usual (BAU) scenario from 2010 to 2050. Under the BAU, agri‐food production increased despite a decline in water resource availability, with gains driven by intensification and increased agricultural productivity. This boosted local prosperity and reduced the amount of agricultural land required to meet future agri‐food demand, thereby reducing pressures on terrestrial ecosystems and creating the space for ecological restoration and carbon storage in soils and biomass. However, agricultural intensification impacted water quality through increases in algal blooms and river salinity. Plain Language Summary: The 17 Sustainable Development Goals represent a comprehensive and ambitious plan to improve society, boost the economy, and protect the environment. However, it's challenging to achieve these goals because they interact with and impact one another in complex ways. To better understand these interactions, we apply a system dynamics model to analyze how different goals influence each other at a local level by involving the input of stakeholders. In this study, we focused on four critical goals: zero hunger, clean water and sanitation, economic growth, and life on land. We explored projections from 2010 to 2050 under business‐as‐usual trends. The results revealed that, even if water becomes scarcer, food production can still go up if we farm smarter and more efficiently. This is good for the local economy and means that less land is needed for farming, which helps the environment. It also creates room for nature to bounce back and for the soil and plants to store more carbon. However, agricultural intensification can adversely affect water quality. Our model supports decision‐makers in balancing multiple goals, identifying potential trade‐offs, and synergies that benefit the sustainable development of local communities. Key Points: We used a participatory approach to co‐design a systems model with stakeholders for analyzing local sustainabilityThe model quantifies the interactions among SDG 2, SDG 6, SDG 8, and SDG 15 and we applied it under a Business‐As‐Usual (BAU) futureUnder the BAU, agri‐food production increased despite less water due to intensification, but there were environmental spillover effects [ABSTRACT FROM AUTHOR]

Low-inflow estuaries are naturally more susceptible to anthropogenic stressors, compared to well flushed systems, with excessive nutrient loading posing a particular threat. This study investigated the benthic diatom community structure of two eutrophic, microtidal estuaries impacted by daily wastewater effluent discharges. It was hypothesised that the community structure would be similar between the warm-temperate Hartenbos and subtropical uThongathi estuaries due to disproportionally high dissolved inorganic nitrogen (H: 38 kg DIN d−1; uT: 67.5 kg DIN d−1) and phosphorus (H: 22 kg DIP d−1; uT: 29.7 kg DIP d−1) inputs from wastewater treatment works (WWTWs). Taxa tolerant of high nutrient conditions proliferated in both systems. However, the dominant taxa differed with the brackish Halamphora coffeaeformis species occurring in the Hartenbos Estuary and the freshwater Navicula rostellata, Sellaphora pupula and Navicula gregaria species in the uThongathi Estuary. The overall benthic diatom diversity in both systems was low (H' > 0 but ≤ 1.5) and indicative of a degraded health state. Temporal differentiation driven by salinity was evident in the Hartenbos Estuary, while changes in community structure were limited to periods of increased river inflow in the uThongathi Estuary. Therefore, while the trophic status of the dominant taxa was determined by the nutrient stress (primary stressor), changes in salinity and river inflow (secondary stressors) shaped the distinct community assemblages observed in each estuary. This study provides insight into the impact of similar anthropogenic-induced pressures in different biogeographical regions and the importance of managing towards a natural dynamic state of microtidal, low-inflow estuaries. [ABSTRACT FROM AUTHOR]

Mangroves are coastal ecosystems dependent on saline water conditions, although freshwater is seasonally present in most types of mangroves. The riparian mangroves have a greater influence of freshwater than salty water, reducing saline stress and allowing greater productivity and diversity. As they are associated with freshwater channels, their hydrology makes them both a source and a sink for sediments, nutrients, and organic matter. The wetlands adjacent to riparian mangroves are mainly freshwater swamps or marshes. To monitor the composition and abundance of the vegetation and the production of litter and roots in the midterm, 27 monitoring units were monitored (22 in mangroves, five in wetlands) in two periods (2015–2016 and 2018–2019). In them, we evaluated biotic characteristics and root production annually, and monthly the litter production and pore and river water salinity. We detected a gradient of salinity spatially and temporally. The salinity gradually decreased as the distance to the river increased. In the winter of 2018–2019 saline intrusion increased the interstitial and river water values by an average of 10 (interstitial water) and 16‰, (river water). This increase caused a significant decrease in litter and root production and augmented the cover of Laguncularia racemosa (freshwater marsh), mortality of herbaceous species (Acrostichum danaeifolium, Typha domingensis, Phragmites australis), and tree species such as Annona glabra and Acoelorraphe wrightii. [ABSTRACT FROM AUTHOR]

Human activities are not only increasing salinization of rivers, they might also be altering the temporal dynamics of salinity. Here, we assess the effect of human activities on the temporal dynamics of electrical conductivity (EC) in 91 Spanish rivers using daily measures of EC from 2007 to 2011. We expected rivers weakly affected by human activities to have low and constant ECs, whereas rivers strongly affected by human activities should have high and variable ECs throughout the year. We collected information on land use, climate, and geology that could explain the spatiotemporal variation in EC. We identified four groups of rivers with differences in EC trends that covered a gradient of anthropogenic pressure. According to Random Forest analysis, temporal EC patterns were mainly driven by agriculture, but de-icing roads, mining, and wastewater discharges were also important to some extent. Linear regressions showed a moderate relationship between EC variability and precipitation, and a weak relationship to geology. Overall, our results show strong evidence that human activities disrupt the temporal dynamics of EC. This could have strong effects on aquatic biodiversity (e.g., aquatic organisms might not adapt to frequent and unpredictable salinity peaks) and should be incorporated into monitoring and management plans. [ABSTRACT FROM AUTHOR]

Anthropogenic salt inputs have impacted many streams in the U.S. for over a century. Urban stream salinity is often chronically elevated and punctuated by episodic salinization events, which can last hours to days after snowstorms and the application of road salt. Here, we investigated the impacts of freshwater salinization on total dissolved nitrogen (TDN) and NO3−/NO2− concentrations and fluxes across time in urban watersheds in the Baltimore-Washington D.C. metropolitan area of the Chesapeake Bay region. Episodic salinization from road salt applications and snowmelt quickly mobilized TDN in streams likely through soil ion exchange, hydrologic flushing, and other biogeochemical processes. Previous experimental work from other studies has shown that salinization can mobilize nitrogen from sediments, but less work has investigated this phenomenon with high-frequency sensors and targeted monitoring during road salt events. We found that urban streams exhibited elevated concentrations and fluxes of TDN, NO3−/NO2−, and specific conductance that rapidly peaked during and after winter road salt events, and then rapidly declined afterwards. We observed plateaus in TDN concentrations in the ranges of the highest specific conductance values (between 1000 and 2000 μS/cm) caused by road salt events. Plateaus in TDN concentrations beyond a certain threshold of specific conductance values suggested source limitation of TDN in watersheds (at the highest ranges in chloride concentrations and ranges); salts were likely extracting nitrogen from soils and streams through ion exchange in soils and sediments, ion pairing in soils and waters, and sodium dispersion of soils to a certain threshold level. When watershed transport was compared across land use, including a forested reference watershed, there was a positive relationship between Cl− loads and NO3−/NO2− loads. This relationship occurred across all sites regardless of land use, which suggests that the mass transport of Cl− and NO3−/NO2− are likely influenced by similar factors such as soil ion exchange, ion pairing, sodium dispersion of soils, hydrologic flushing, and biogeochemical processes. Freshwater salinization has the potential to alter the magnitude and timing of total dissolved nitrogen delivery to receiving waters during winter months following road salt applications, and further work should investigate the seasonal relationships of N transport with salinization in urban watersheds. [ABSTRACT FROM AUTHOR]

Estuaries have strong physicochemical gradients that lead to complex variability and often high rates of biogeochemical processes. The biogeochemistry of many estuaries is also increasingly impacted by human activities. Yet our understanding of estuarine biogeochemistry remains skewed towards temperate systems in the northern hemisphere, with far less research from tropical estuaries. This study examined seasonal and spatial variability in dissolved organic matter (DOM) and nutrient biogeochemistry along a partly eutrophic, mixed agricultural/urban estuary system in Southeast Asia, the Johor River and the East Johor Strait. Dissolved organic carbon (DOC) and chromophoric DOM (CDOM) properties showed non-conservative mixing, indicating significant DOM inputs along the estuary. The CDOM spectral slopes and CDOM:DOC ratios suggest that these inputs are dominated by terrigenous, soil-derived DOM along the Johor River, but that phytoplankton production and microbial recycling are more important DOM sources in the Johor Strait. Nitrate consistently showed conservative mixing, while nitrite concentrations peaked at intermediate salinities of 10–25. Ammonia decreased with salinity in the Johor River. In the Johor Strait, however, ammonia increased up to 50 µmol l-1, often dominating the dissolved inorganic nitrogen (DIN) pool. Phosphate was low (<0.5 µmol l-1) throughout the Johor River, but increased in the Johor Strait, where DIN:phosphate ratios were typically at or above 16:1. This suggests that phytoplankton in the Johor Strait may sometimes experience phosphorus limitation. Moreover, internal recycling is likely important for maintaining high nutrient concentrations in the Johor Strait. [ABSTRACT FROM AUTHOR]

Along coasts, biologically diverse terrestrial wetlands and marine ecosystems maintain complex hydrological connections that influence groundwater quality. The coastline of Florida's panhandle is home to globally rare coastal dune lakes that are hydrologically influenced by unique wet prairies within their watersheds. Little is known regarding how changes in ecosystem structure and composition of wet prairies influences groundwater chemistry within these coastal dune lake watersheds. To identify how physical and biological characteristics of terrestrial wetlands influence water chemistry, we analyzed water quality parameters along an upland to wetland gradient of shrub-encroached and fire-maintained wetlands within four of Florida's coastal dune lake watersheds between 2018 and 2021. Shrub-encroached wetlands had significantly higher (p ≤ 0.01) specific conductivity, salinity, acidity, and ion concentrations (Cl−, SO42−, K+, Na+, and Mg2+) than fire-maintained wetlands. Ions in groundwater were similar across the upland to wetland gradient with exception of chloride which was significantly lower (p ≤ 0.01) at upper slope positions where encroaching shrubs were less dense. The sulfate in groundwater was twice that of streams and salinity was most concentrated at the bottom slope positions. As results show that shrub encroachment has a measurable relationship with water chemistry, restoration of herbaceous wetlands through shrub removal may improve water quality and minimize future impacts to Florida's coastal dune lakes. [ABSTRACT FROM AUTHOR]

Florida spring-fed rivers are known for their submerged aquatic vegetation (SAV). which provides habitat for fish and aquatic crustaceans and food for the Florida manatee. Salinization of coastal spring-fed rivers due to climate change and sea level rise have been documented and can cause changes 10 SAV communities. This study investigated patterns and relationships between the SAV community and salinity of the Chassahowitzka River (Citrus County, FL, USA) to extrapolate the long-term effects of river salinization. A distinct dichotomy was seen in the SAV community structure: communities where salt tolerant Chaetomorpha spp. was present and communities where freshwater filamentous algae species were present. Freshwater filamentous algae demonstrated an inverse relationship with salinity. Chaetomorpha spp. replaced the freshwater filamentous algae in regions too salty for freshwater algae to grow. These patterns in the SAV community resulted in three different ecological zones in the Chassahowitzka River: low salinity/freshwater tidal, transition, and brackish zones. While freshwater filamentous algae and Chaetomorpha spp. were characteristic of the freshwater and brackish zones respectively, both species were identified within the transition zone. Utilizing the presence/absence of these macroalgae types could allow for an in-situ approach of characterizing regions of coastal spring-fed rivers that show increased salinization. [ABSTRACT FROM AUTHOR]

Simple Summary: Climate-related salinization of inland waters is observed in many regions of the world as a major environmental problem affecting natural processes in aquatic ecosystems. In order to better predict and control these changes, it is important to study the responses of aquatic fauna to increasing salinity. Macrozoobenthic fauna, which includes mollusks, small crustaceans, and insect larvae, constitutes the main food base for fish and water birds. Due to their relatively short life cycles, large species diversity, and high abundance, macrozoobenthos are the best indicators of changing water salinity. To determine the species richness, distribution, and salinity tolerance of macrozoobenthos, we investigated 17 small rivers with different water salinity in the southern arid region of the East European Plain. The study shows that the species richness gradually decreases with an increase in water salinity in the rivers. In freshwater rivers, the macrozoobenthos fauna includes more than 100 species, whereas, in hypersaline rivers with salinity comparable to seawater, only 10 species were found. A total of 5 of the 156 invertebrate species can be used as indicators of water salinization in rivers of the arid regions of Europe. This study investigated the species composition, distribution, and salinity tolerance of macrozoobenthos in 17 small rivers in the southern arid region of the East European Plain, which are characterized by a small channel gradient, slow-flowing or stagnant water bodies, and a wide range of water salinity, varying between 0.18 and 30 g L−1. In total, 156 taxa were found, among which 66 were Diptera species. The study revealed that the formation of benthic communities in the rivers is influenced by natural factors of the catchment basins, including the flat landscape with sparsely developed relief differentiation, climate aridity, and the widespread occurrence of saline soils and groundwater, largely related to the sedimentation of the ancient Caspian Sea and modern climate changes. These conditions are favorable for the occurrence of lacustrine macrozoobenthic species in freshwater, euryhaline, and halophilic ecological groups. The investigation revealed a decrease in species richness in response to an increase in water salinity. The five identified halophilic species Tanytarsus kharaensis, Glyptotendipes salinus, Cricotopus salinophilus, Chironomus salinarius, and Palpomyia schmidti can be used as indicators of river ecosystem salinization. [ABSTRACT FROM AUTHOR]

Soil salinization is a widespread phenomenon leading to land degradation, particularly in regions with brackish inland aquaculture ponds. However, because of the high geographical and temporal fluctuation, monitoring vast areas provides substantial challenges. This study uses remote sensing data and machine learning techniques to predict soil salinity. Four linear models, namely linear regression, least absolute shrinkage and selection operator (LASSO), ridge, and elastic net regression, and three boosting algorithms, namely XGB regressor, LightGBM, and CatBoost regressor, were used to predict soil salinity. Cross-validation was performed by splitting the data into 30% for model testing and 70% for model training. Multiple metrics such as determination coefficient (R2), root mean square error (RMSE), mean square error (MSE), and mean absolute error (MAE) were used to compare the performances of these algorithms. By comparison, the CatBoost regressor model performed better than the other models in both testing (MAE = 0.42, MSE = 0.28, RMSE = 0.53, R2 = 0.92) and training (MAE = 0.49, MSE = 0.36, RMSE = 0.60, R2 = 0.90) phases. Hence, the CatBoost regressor model was recommended for monitoring soil salinity in India's massive inland aquaculture zone. [ABSTRACT FROM AUTHOR]

• Haihe River is a sluice-controlled coastal plain river showing both salinity and trophic gradients. • TSI posed a greater influence than salinity on the CDOM abundance. • TSI affected the CDOM abundance more than the fluorescence intensity. • Salinity affected the abundance of CDOM but rarely affected FDOM. Due to the combined effect of sluices and sea tide, the sluice-controlled coastal plain river would be characterized by both trophic state and salinity gradients, affecting the spatiotemporal optical properties of dissolved organic matter (DOM). In this study, we investigated the spatiotemporal variation of water quality parameters and optical properties of DOM in the Haihe River, a representative sluice-controlled coastal plain river in Tianjin, China. A significant salinity gradient and four trophic states were observed in the water body of the Haihe River. Two humic- and one protein-like substances were identified from the DOM by the three-dimensional fluorescence spectra combined with the parallel factor (PARAFAC) analysis. Pearson's correlation analysis and redundancy analysis (RDA) showed that the salinity significantly affected the abundance of chromophoric DOM (CDOM) but did not cause significant changes in the fluorescence optical characteristics. In addition, the effect of Trophic state index (TSI) on the CDOM abundance was greater than that on the fluorescence intensity of fluorescent dissolved organic matter (FDOM). In the water body with both salinity and trophic state gradients, TSI posed a greater influence than salinity on the CDOM abundance. Our results fill the research gap in spatiotemporal DOM characteristics and water quality variation in water bodies with both salinity and trophic state gradients. These results are beneficial for clarifying the joint influence of saline intrusion and sluices on the DOM characteristics and water quality in sluice-controlled coastal plain rivers. [Display omitted] [ABSTRACT FROM AUTHOR]

Heterosigma akashiwo is a unicellular microalga which can cause massive mortality in both wild and cultivated fish worldwide, resulting in substantial economic losses. Environmental parameters such as salinity, light, and temperature showed a significant effect on bloom initiation and the toxicity of H. akashiwo. While in previous studies a one-factor-at-a-time (OFAT) approach was utilized, which only changes one variable at a time while keeping others constant, in the current study a more precise and effective design of experiment (DOE) approach, was used to investigate the simultaneous effect of three factors and their interactions. The study employed a central composite design (CCD) to investigate the effect of salinity, light intensity, and temperature on the toxicity, lipid, and protein production of H. akashiwo. A yeast cell assay was developed to assess toxicity, which offers rapid and convenient cytotoxicity measurements using a lower volume of samples compared to conventional methods using the whole organism. The obtained results showed that the optimum condition for toxicity of H. akashiwo was 25 °C, a salinity of 17.5, and a light intensity of 250 μmol photons m−2 s−1. The highest amount of lipid and protein was found at 25 °C, a salinity of 30, and a light intensity of 250 μmol photons m−2 s−1. Consequently, the combination of warm water mixing with lower salinity river input has the potential to enhance H. akashiwo toxicity, which aligns with environmental reports that establish a correlation between warm summers and extensive runoff conditions that indicate the greatest concern for aquaculture facilities. [ABSTRACT FROM AUTHOR]

The large influx of freshwater and mixing of different water masses make simulating salinity challenging for the Bay of Bengal (BoB) region. This study analyses the variability of the simulated sea surface salinity (SSS) using models present in the Coupled Modal Intercomparison Project Phase 6 (CMIP6). We collected data for 37 models from CMIP6 and validated them against the Argo (2005-14) and Aquarius (2011-14) data. Based on the skill scores, we narrowed down our search to one CMIP6 model, viz. CIESM. This model was used to study the freshwater spread (FWS) in BoB during different seasons. We found that the correlation between pH and FWS was appreciable. The CIESM model was then used to project the future trends for 10 years for the tier-1 scenario. The trend analysis of future projections revealed a positive trend in SSP1-2.6, with a decreasing trend in SSP2-4.5 and SSP5-8.5. [ABSTRACT FROM AUTHOR]

Winter road salt use leads to the salinization of freshwater habitats. Freshwater organisms experience negative effects due to increased chloride ions, including algae in periphyton biofilms. This study examines the effects of road salt on algal assemblage composition, lipid production, and enzyme activity. Five streams throughout Erie County, New York, US were sampled monthly from October 2018 to March 2019. Chloride concentrations in all streams averaged 203.6 Cl- mg/L throughout the winter and had a highly significant relationship (rs = 0.82) with developed land use. Algal biodiversity scores decreased with elevated salinity (rs = 0.11). Algae exhibited the greatest total lipids in January (2.92 mg/m2) and the lowest in March (1.03 mg/m2). Similar trends were observed with x3 and x6 compounds. Overall desaturase D6 activity trended with stream Cl- concentrations, mainly along x6 pathways, suggesting an inflammatory stress response. Algal assemblages exhibited evidence of chronic salt exposure through impaired taxonomic composition and patterns of lipid production that followed trends in stream water salinity. These effects suggest road salt applications have negative effects on stream primary producers with consequences for higher trophic levels. [ABSTRACT FROM AUTHOR]

Faisalabad is a major industrial area in Pakistan's Punjab province that discharges wastewater into the Chenab River. Industrial effluents in Faisalabad are predicted to pose a significant threat to the riparian vegetation of the Chenab River and nearby vegetation. Heavy metal pollution of plants, water, and soils is one of the biggest problems worldwide that needs to be addressed because heavy metals above normal levels are extremely dangerous to both riparian vegetation and wildlife. The results indicated high levels of pollution in the industrial effluents as well as in the river in terms of salinity, metal toxicity, TSS, TDS, SAR, the acidic and alkaline nature of the industrial effluents, and the spread of industrial effluents up to 15 square kilometres in the Chenab River. Despite the higher pollution, four plants were found at all sites: Calotropis procera, Phyla nodiflora, Eclipta alba and Ranunculus sceleratus. It was found that most of the selected plants were phytoaccumulators, making them best suited to survive in harsh environments such as those with industrial pollution. The Fe concentration in the plant constituents was the highest, along with Zn, Pb, Cd, and Cu, all of which were above the permissible limits of the WHO. The metal transfer factor (MTF) was higher in most of the plants studied, and even exceeded 10 at some severely affected sites. Calotropis procera proved to be the most suitable plant for growth on drainage systems and also at river sites, as it had the highest importance value across all sites and seasons. [ABSTRACT FROM AUTHOR]

Mangrove environments are often characterized by large fluctuations in salinity, ranging from freshwater to hyper‐saline conditions. Most reports have focused on the mechanisms by which mangroves adapt to high salinity. However, how mangroves cope with seasonal freshwater habitats has seldom been studied. To address this question, we surveyed the river salinity and leaf traits (chlorophyll fluorescence, ion concentrations, carbon isotope ratios and osmolality) of Aegiceras corniculatum (L.) Blanco (river mangrove) along a freshwater‐dominated river. A. corniculatum at the upstream site was subjected low salinity, being in fresh water for a long period (up to 310 h) in the wet season, which drastically diminished during the dry season. At both sites, the actual photosystem II efficiency (ФPSII) and electron transport rates (ETR) of the leaves were higher in the wet season than in the dry season, and the carbon isotope (δ13C), ions (Na+ and Cl−) concentrations and osmolality showed no seasonal variations. However, the maximal quantum yield of PSII photochemistry (Fv/Fm), the proportion for closed PSII reaction centres (1 − qP) and non‐photochemical quenching (NPQ) of the leaves at the upstream site maintained high levels in the wet season. This quenching analysis indicated that there was a down‐regulation of photoprotection at the upstream site during wet season. An explanation for this is that long‐term freshwater is a stressful environment for A. corniculatum and maintaining certain level Na+ and Cl− in saline water episode is necessary for A. corniculatum to maintain low water potentials to take up water. [ABSTRACT FROM AUTHOR]

Shallow groundwater in coastal aquifers is a highly dynamic and complex system with a high risk of seawater intrusion. Analyzing the spatio-temporal dynamic patterns of groundwater can help to manage the groundwater resource and prevent it from degradation. Based on the groundwater level (GWL) and electrical conductivity (EC) monitoring data of 18 observation wells in the Yellow River Delta (YRD) from 2004 to 2010, this research analyses the groundwater dynamics using a robust seasonal trend decomposition technique (STL) and spatial interpolation method to detect the groundwater spatio-temporal dynamic patterns of groundwater level and salinity. Combined with hydro-climatic data, the Pearson correlation method and the Mann-Kendall (MK) trend analysis were used to further reveal the impacts that induce their trends and seasonal variations. Our analyses show that the risk of seawater intrusion into local shallow aquifers in this region is high, with the mean groundwater level over 42% of the region lower than the local sea level, and the mean groundwater EC over 96% of the region met the standards for seawater intrusion. In addition, the trends of groundwater level generally declined by 0.01~0.45 m/a and salinity increased by 1.153~25.608 μs/cm.a, which are consistent with the trend of precipitation decline. The seasonal dynamics of groundwater level and salinity are highly correlated with the seasonal components of rainfall and evaporation. It can be concluded that the extent of seawater intrusion will increase in the future with sea level rise. The approaches used in this study proved to be effective and can certainly serve as an example for the analysis of the spatio-temporal dynamics of groundwater in other coastal regions. [ABSTRACT FROM AUTHOR]

In 2020, Yellow River runoff was more than twice as much as past years, and the proportion of strong winds was also higher than that in past years, which will inevitably lead to a change in salinity plume distribution in the Yellow River Estuary and Laizhou Bay. Based on FVCOM numerical modelling, this paper presents the spatial salinity distribution and dispersion of the Yellow River Estuary and Laizhou Bay during the wet and dry seasons in 2020. We used data from six tidal and current stations and two salinity stations to verify the model, and the results showed that the model can simulate the local hydrodynamic and salinity distribution well. The influence of river discharge and wind speed on salinity diffusion was then investigated. The simulation results showed that under the action of residual currents, fresh water from the Yellow River spread to Laizhou Bay, and the low salinity area of Laizhou Bay was mainly distributed in the northwest. The envelope area of 27 psu isohaline can account for about one-quarter of Laizhou Bay in the wet season, while the low-salinity area was only concentrated near the estuary of Yellow River in the dry season. River discharge mainly affects the diffusion area and depth of fresh water, and wind can change the diffusion structure and direction. In the wet season, with the increase in wind speed, the surface area of the plume decreased gradually, and the direction of the fresh water plume changed counterclockwise from south to north. During the dry season, the plume spread to the northwest along the nearshore. The increase in wind speed in the early stage increased the surface plume area, and the plume area decreased above a wind speed of 10 m/s due to the change in the turbulence structure. The model developed and the results from this study provide valuable information for establishing robust water resource regulations for the Yellow River. This is particularly important to ensure that the areas with low salinity in the Yellow River Estuary will not decrease and affect the reproduction of fish species. [ABSTRACT FROM AUTHOR]

Salt pollution is a threat to freshwater ecosystems. Anthropogenic salt inputs increase lake and stream salinity, and consequently change aquatic ecosystem structure and function. Elevated salt concentrations impact species directly not only through osmoregulatory stress, but also through community‐level feedbacks that change the flow of energy and materials through food webs. Here, we discuss the implications of road salt pollution on freshwater rivers and lakes and how "one size fits all" ecotoxicity thresholds may not adequately protect aquatic organisms. This article is categorized under:Science of Water > Water QualityWater and Life > Nature of Freshwater EcosystemsWater and Life > Stresses and Pressures on Ecosystems [ABSTRACT FROM AUTHOR]

Background: Secondary salinity of river water reduces the value of ecosystem services, negatively impacting the entire aquatic ecosystem and reducing the possibility of water use. In Poland, significant anthropogenic salinity of rivers and water reservoirs is usually associated with mining activity consisting of pumping salty mine water into settling ponds or often directly into rivers. However, to assess the reasons for the salinity of the Vistula waters, it is necessary to identify all sources of salt in surface waters, enabling the assessment of the salt load in the waters. Methods: The paper presents four sources of data which have been compiled to propose a valuable method for analyzing the threat of the river. Patrol monitoring was one method of data acquisition, and State Environmental Monitoring data ware also used. Clustering and correlation statistical techniques were used for analysis. Results: Of the 20 physical and chemical parameters analyzed, chloride, calcium sulphate and magnesium ions are important for salinity. Measurements with multi-parameter probes allowed for the identification of increased salinity pressure sites, while flow analyses were required to calculate the load. Conclusions: The Vistula River had the highest concentrations of the analyzed ions in the Silesia Region. The use of patrol monitoring can be highly useful in determining the causes of emerging problems with water quality and supporting State Environmental Monitoring. [ABSTRACT FROM AUTHOR]

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Species invasions are a global problem of increasing concern, especially in highly connected aquatic environments. Despite this, salinity conditions can pose physiological barriers to their spread, and understanding them is important for management. In Scandinavia's largest cargo port, the invasive round goby (Neogobius melanostomus) is established across a steep salinity gradient. We used 12,937 SNPs to identify the genetic origin and diversity of three sites along the salinity gradient and round goby from western, central and northern Baltic Sea, as well as north European rivers. Fish from two sites from the extreme ends of the gradient were also acclimated to freshwater and seawater, and tested for respiratory and osmoregulatory physiology. Fish from the high‐salinity environment in the outer port showed higher genetic diversity, and closer relatedness to the other regions, compared to fish from lower salinity upstream the river. Fish from the high‐salinity site also had higher maximum metabolic rate, fewer blood cells and lower blood Ca2+. Despite these genotypic and phenotypic differences, salinity acclimation affected fish from both sites in the same way: seawater increased the blood osmolality and Na+ levels, and freshwater increased the levels of the stress hormone cortisol. Our results show genotypic and phenotypic differences over short spatial scales across this steep salinity gradient. These patterns of the physiologically robust round goby are likely driven by multiple introductions into the high‐salinity site, and a process of sorting, likely based on behaviour or selection, along the gradient. This euryhaline fish risks spreading from this area, and seascape genomics and phenotypic characterization can inform management strategies even within an area as small as a coastal harbour inlet. [ABSTRACT FROM AUTHOR]

Freshwater salinization of rivers is occurring across the globe because of nonpoint source loading of salts from anthropogenic activities such as agriculture, urbanization, and resource extraction that accelerate weathering and release salts. Multidecadal trends in river salinity are well characterized, yet our understanding of annual regimes of salinity in rivers draining diverse central and western U.S. landscapes and their associated catchment attributes is limited. We classified annual salinity regimes in 242 stream locations through dynamic time warping and fuzzy c‐medoids clustering of salinity time series. We found two dominant regimes in salinity characterized by an annual summer–fall peak or spring decline. Using random forest regression, we found that precipitation amount, stream slope, and soil salinity were the most important predictors of salinity regime classification. Advancing our understanding of salinity regimes in rivers will improve our ability to predict and mitigate the effects of salinization in freshwater ecosystems through management interventions. [ABSTRACT FROM AUTHOR]

This study considers the integration of multistage flash (MSF) desalination with hydrate-based desalination (HBD) precursor to improve MSF performance in terms of distillate production, longevity, and operational conditions. This is accomplished by a comprehensive analysis of the rate of scale formation, distillate production, and the MSF performance ratio by means of mathematical modelling conducted in Simulink software. To calibrate the effectiveness of HBD as precursor to the MSF desalination process, two MSF models were created: the once-through (OT) and brine recycle (BR) configurations. The MSF models were validated in terms of stagewise distillate production, brine temperature, and coolant temperatures with data from the literature, while neglecting the non-equilibrium allowance. The operational performance of the proposed integration approach was evaluated in terms of the deposition rates of CaCO3, scale thickness, fouling resistance, overall heat transfer coefficient, performance ratio, and production ratio. The examination was conducted from the perspective of water salinity and stream temperature for the integrated HBD-MSF systems. The results show that due to the quality of output water in terms of salinity and temperature, the integration of HBD and MSF improved the performance of MSF by substantially reducing scale formation rates as well as increasing the production of distillate where the scale formation rates were 40.6% and 36.3% lower for the hybrid HBD-MSF-OT and HBD-MSF-BR systems, respectively. [ABSTRACT FROM AUTHOR]

Electrical resistivity tomography (ERT) has seen increased use in the monitoring the condition of river embankments, due to its spatial subsurface coverage, sensitivity to changes in internal states, such as moisture content, and ability to identify seepage and other erosional process with time‐lapse ERT. Two‐dimensional ERT surveys are commonly used due to time and site constraints, but they are often sensitive to features of anomalous resistivity proximal to the survey line, which can distort the resultant inversion as a three‐dimensional (3D) effect. In a tidal embankment, these 3D effects may result from changing water levels and river water salinities. ERT monitoring data at Hadleigh Marsh, UK, showed potential evidence of 3D effects from local water bodies. Synthetic modelling was used to quantify potential 3D effects on tidal embankments. The modelling shows that a 3D effect in a tidal environment occurs (for the geometries studied) when surveys are undertaken at high water levels and at distances less than 4.5 m from the electrode array with 1 m spacing. The 3D effect in the modelling is enhanced in brackish waters, which are common in tidal environments, and with larger electrode spacing. Different geologies, river water compositions, and proximities to the model parameters are expected to induce a varied 3D effect on the ERT data in terms of magnitude, and these should be considered when surveying to minimize artefacts in the data. This research highlights the importance of appropriate geoelectrical measurement design for tidal embankment characterization, particularly with proximal and saline water bodies. [ABSTRACT FROM AUTHOR]

All landscapes, including estuarine islands, normally try to restore their geomorphic isostasy in all anthropogenic interventions on land dynamics. Munroe Island has been experiencing drastic environmental degradation, such as land subsidence, severe tidal/monsoon flooding, subsidence of build-ups and a drastic decay in agricultural productivity. This paper examines the role of anthropo-geomorphic interventions causing for the land degradation in Munroe Island through a multidisciplinary approach. Multidated, multiresolution satellite products and published maps, spanning a period of about six decades from 1960 to 2021, were used to understand the different geomorphic and geographical processes in the study area. Evaluation of the temporal bathymetric datasets, salinity measurements of the river and estuary, borehole data logs of the area and electrical resistivity surveys of the island were analyzed to find out the causative factors for the disturbances in the land neutrality, along with the tidal hydrodynamic changes in the region. The study shows about 14% of the total land area was vanished during the study period, and more than 25% of the area is under stress, leading to further land degradation. More than 500 households are forced to vacate their residence due to land subsidence/flooding. Lack of required freshwater and sediment supply from the Kallada river after the construction of the Thenmala reservoir in the Kallada river as well as the uncontrolled sand mining prevailed are the key factors for the environmental degradation of Munroe Island. The paper describes the role and colinkages of human-induced hydrogeomorphic interventions on a geomorphic system, in charge of the environmental degradation and land subsidence crisis of an estuarine island ecosystem and discusses the concerns related to the management strategies of such region. [ABSTRACT FROM AUTHOR]

Salinity in deltaic systems is expected to increase in the near future due to sea level rise. This will cause severe environmental consequences because salinity can be detrimental to agriculture, aquaculture and human consumption. Tidal dynamics are important in regulating salinity in river deltas. However, there is still uncertainty about the influence of different tidal amplitudes on deltas' salinity. This paper investigates the impact of various tidal amplitudes on the spatiotemporal salinity distribution in deltas through three-dimensional idealized modelling. Numerical simulations are carried out with a common hydrograph and different tidal ranges. Both tide-influenced and river-dominated cases were considered. Results suggest that small increases in the tidal amplitude in river-dominated or low tidal regimes cases can have positive effects against salinization. Tide-induced mixing helps to increase freshwater areas and volumes. The water in the delta remains fresh for longer periods in scenarios representative of microtidal regimes. Further increases in the tidal amplitude to meso- and macrotidal levels reverse these effects and reduce freshwater areas and volumes. Results were used to test how salinity correlates with channel orders and river discharge in the presence of tides. These correlations are controlled more by bathymetry than tidal forcing. This study provides important insights into how changes in tidal range could impact spatiotemporal salinity distributions in deltas. [ABSTRACT FROM AUTHOR]

Since reverse osmosis (RO) is often limited to a water recovery of 70–85 %, implementing a secondary process like electrodialysis metathesis (EDM) to treat concentrate can increase system water recovery. This study explores salt-free electrodialysis metathesis (SF-EDM) as an alternative to conventional EDM to investigate its performance in the zero discharge desalination (ZDD) process. SF-EDM utilizes monovalent-selective ion exchange membranes, eliminating the need for sodium chloride (NaCl) as a substitution solution. This approach generates one diluate stream and two highly soluble concentrate streams enriched in calcium and sulfate, respectively. In this article, a series of lab-scale tests based on synthetic and real RO concentrate were performed to investigate how SF-EDM performs operating at high water recovery with a feedwater with high scaling potential. We critically analyze the performance in terms of salinity reduction, selectivity, and energy consumption. Results of the study show that without the addition of NaCl, the process was able to selectively separate sulfate and calcium into two concentrate streams achieve a salinity reduction of 93 % and a total system water recovery (RO and SF-EDM) of 90 %. A technoeconomic analysis found SF-EDM to be 80 % of the cost of conventional EDM making it a competitive technology for brackish water RO concentrate management. [Display omitted] • SF-EDM was able to achieve a salinity reduction >90 %. • SF-EDM successfully separates mono- and divalent ions into two different concentrate streams. • Specific energy consumption of SF-EDM ranged between 1 and 7 kWh/m3. • SF-EDM has a levelized cost of water 80 % less than conventional EDM. [ABSTRACT FROM AUTHOR]

[Display omitted] • The solar-driven interfacial evaporator (DLRCA) is upcycled from waster cotton fabrics. • Optimum evaporation rate was attained by differential channel size modulating of the layers. • DLRCA has an evaporation rate of 3.20 kg m−2h−1 and an 80.0% solar-to-vapor conversion efficiency. • Ion removal efficiency over 99.5% in seawater desalination and wastewater treatment was achieved. Constructing efficient solar-driven interfacial evaporators (SDIEs) derived from biomass or waste stream materials (e.g., cellulose) is still challenging due to their less elaborate porous structure. Herein, we showed waste cotton fabrics could be dissolved and regenerated into aerogels with tunable channels suitable for constructing a double-layered SDIE. The evaporator consists of a polypyrrol-coated top layer featuring vertical channels with larger pores and a hydrophilic bottom layer featuring smaller pores. With such design, the photothermal and pro-evaporative capabilities of the top layer was coupled with the strong capillary effect of the bottom layer to drive effective evaporation. A desirable evaporation rate of 3.20 kg m−2h−1, 80.0% solar-to-vapor conversion efficiency under 1 sun irradiation, and a reduced evaporation enthalpy of 962 J g−1 was achieved. The SDIE also exhibits high purification efficiency (exceeding 99%) during long-term operation of seawater desalination and shows great potential in treatment of waste streams of high salinity dyeing effluent. In summary, this work demonstrates a case of upcycling waste cotton fabrics for water desalination. [ABSTRACT FROM AUTHOR]

As the intersection between land and sea, the estuary is a hotpot for natural and human-induced processes that affect its physical and chemical characteristics, as well as biodiversity and ecosystems. Due to a combination of freshwater discharge and the unique topography of river estuaries, submesoscales with a spatial scale of O (1) km can be easily generated due to the presence of strong salinity fronts at river estuaries. As the biggest river in Asia, the basically dynamical characteristics and their seasonal mechanisms of submesoscales at the Yangtze estuary remain unclear. Using a nested high-resolution (300 m) simulation established by the Coastal and Regional Ocean Community model (CROCO), the seasonal variability of submesoscales at the Yangtze estuary is investigated and the underlying generation mechanisms are analyzed based on the analysis of kinetic energy budget. The results of normalized relative vorticity, horizontal salinity gradient, and submesoscale kinetic energy (SMKE) show that submesoscale processes have a seasonal variation at the Yangtze estuary. This seasonality is tightly related to the freshwater input with a correlation coefficient of up to 0.66 (the confidence level >99%). To figure out the dominant energy sources that control the SMKE budget, five terms including the baroclinic term (BC), the barotropic term (BT), the advection of submesoscale kinetic energy term (ADK), the pressure work term (PW), and vertical mixing term (VM) are diagnosed. The results suggest that BC, BT, and PW are the source producing SMKE, while ADK and VM tend to dissipate SMKE. This work suggests the important role of submesoscale activities in the energy cascade and enhancing the transports of tracers at the estuary. • Submesoscale processes show strong seasonal variability at the Yangtze estuary. • Enhanced submesoscale activity is tightly related to the freshwater input. • The release of the available potential energy is the major source of submesoscale kinetic energy. [ABSTRACT FROM AUTHOR]

• Porewater from sediments cores is employed to assess salinization processes. • Depositional environments are related with main redox processes. • Trapped paleo seawater in aquitards is identified as main salinization source. • PCA related trace elements presence with ionic strength and redox processes. To counteract the ongoing salinization of coastal aquifers, which poses a significant environmental and socioeconomic challenge to local communities, it is necessary to first understand the origin and mechanisms of this phenomenon. This study investigates the origins of salinity in the Volturno River lowland in Southern Italy and reveals that the primary source in the area is paleo-seawater entrapped within sediments that were subject to evapoconcentration processes. By systematically collecting sediment samples at variable depths and locations and extracting porewaters, a comprehensive understanding of the interplay between freshwater and saline water was gained, including complex patterns of vertical stratification of groundwater salinity. The study highlights the limitations of traditional methods that rely on salinity monitoring via integral depth sampling, particularly in capturing the vertical redox and salinity gradients characteristics of layered aquifer/aquitard systems. On the contrary, environmental tracers, like chloride and bromide, provide valuable insights into the sources of groundwater salinity, distinguishing between current seawater intrusion and other causes, such as paleo-seawater and return flow from drained agricultural land. Results suggest that the majority of salinity does not originate from modern seawater intrusion or recent evaporation. Instead, it can be attributed to paleo-seawater affected by evapoconcentration processes. This study has broader implications for the sustainable management of coastal aquifers and the safeguarding of freshwater resources. While our findings are specific to the Volturno River coastal area, the methodologies and insights here presented can be reproduced in every coastal region facing similar salinity challenges. [ABSTRACT FROM AUTHOR]

We estimated the error range of the simulated salinity and seawater temperature based on the uncertainty of the river discharge into Ise Bay in a nowcasting numerical simulation model. We used two methods for calculating the river discharge forcing. In the first method, precipitation was used as the input for the storage function method. In the second method, the Basin Rainfall Index was used, which is a nowcasting dataset of river discharge simulated by the Japan Meteorological Agency. The uncertainty in annual river discharge in both methods was estimated to be within ±30 %. Simulations were conducted using the hydrodynamic simulation model. Annual simulation error ranges associated with the uncertainty in river discharge for salinity and seawater temperature were estimated to be approximately ±1.2 and ±0.15 °C, respectively. We proposed a practical research procedure that can be applied to other models and the simulation of the water environment of coastal and estuary areas. • Procedure for determining uncertainty in river discharge is proposed. • Salinity and water temperature error ranges with river uncertainty were estimated. • River discharge uncertainty affects spatiotemporal salinity/water temperature bias. • Practical research procedure is proposed that can be applied to other model tasks. • Error range of hypoxia in seawater can be estimated applying the proposed method. [ABSTRACT FROM AUTHOR]