Water Systems Research Articles

The Impact of Climate-Related Security Risks on Community Values: Insights from Zambia’s Southern Province

Abstract This article explores the impact of climate-related security risks on community values and how that impact influences responses to the risks. Research and practice have paid little attention to how non-material and subjective conditions, especially values, mediate the climate-security nexus. We focused on the impact of land conflicts and food insecurity (as examples of climate-related security risks) on community values through a study of two rural communities in Zambia’s southern province using impact rating, focus-group discussions (FGD s), and interviews. Innovatively, we began by identifying community values and asking about the impact of climate security risks on community values instead of what ‘experts’ perceive or consider to be risks. We found that, firstly, participants from both communities perceived both land conflicts and food insecurity as having a strong to very strong influence on their values. Secondly, women perceive the impact of land conflicts and food insecurity on values to be greater than men do. Thirdly, the perception of the impact of climate-related security risks on values is prevalent among communities in Zambia’s southern province. The article concludes that values are crucial and central determinants in how communities interpret and respond to climate-related security risks, as well as how they engage with food, land, and water systems. It recommends that policymakers and practitioners integrate community values for effective and sustainable climate-related security risk policies and interventions.

Nexus Framing of Sustainability Issues: Feasibility, Synergies, and Trade-Offs in Terms of Water-Energy-Food

Multisectoral integration has been at the core of sustainability debates and is continuously rearticulated through different concepts. Following the 2007–2008 financial, food, and energy crises, a new concept, the water–energy–food nexus, gained prominence to identify trade-offs and synergies between water, energy, and food systems and guide the development of cross-sectoral policies. The nexus is essentially a systems-based perspective that explicitly recognizes these three systems as both interconnected and interdependent, and thus integrated approaches are required that move beyond sectoral, policy, and disciplinary silos. The nexus is also a political process, one in which the interplay of different types of power, as well as the actors wielding them, is not just a procedurally technical one. This tension between the nexus as a complex system and the nexus as a political process constitutes the core debating idea, in terms of feasibility, methods, and theory, in this article.

Insights into water insecurity in Indigenous communities in Canada: assessing microbial risks and innovative solutions, a multifaceted review.

Canada is considered a freshwater-rich country, despite this, several Indigenous reserves struggle with household water insecurity. In fact, some of these communities have lacked access to safe water for almost 30 years. Water quality in Canadian Indigenous reserves is influenced by several factors including source water quality, drinking water treatments applied, water distribution systems, and water storage tanks when piped water is unavailable. The objective of this multifaceted review is to spot the challenges and consequences of inadequate drinking water systems (DWS) and the available technical and microbiological alternatives to address water sanitation coverage in Indigenous reserves of Canada, North America (also known as Turtle Island). A comprehensive literature review was conducted using national web portals from both federal and provincial governments, as well as academic databases to identify the following topics: The status of water insecurity in Indigenous communities across Canada; Microbiological, chemical, and natural causes contributing to water insecurity; Limitations of applying urban-style drinking water systems in Indigenous reserves in Canada and the management of DWS for Indigenous communities in other high-income countries; and the importance of determining the microbiome inhabiting drinking water systems along with the cutting-edge technology available for its analysis. A total of 169 scientific articles matched the inclusion criteria. The major themes discussed include: The status of water insecurity and water advisories in Canada; the risks of pathogenic microorganisms (i.e., Escherichia coli and total coliforms) and other chemicals (i.e., disinfection by-products) found in water storage tanks; the most common technologies available for water treatment including coagulation, high- and low-pressure membrane filtration procedures, ozone, ion exchange, and biological ion exchange and their limitations when applying them in remote Indigenous communities. Furthermore, we reviewed the benefits and drawbacks that high throughput tools such as metagenomics (the study of genomes of microbial communities), culturomics (a high-efficiency culture approach), and microfluidics devices (microminiaturized instruments) and what they could represent for water monitoring in Indigenous reserves. This multifaceted review demonstrates that water insecurity in Canada is a reflection of the institutional structures of marginalization that persist in the country and other parts of Turtle Island. DWS on Indigenous reserves are in urgent need of upgrades. Source water protection, and drinking water monitoring plus a comprehensive design of culturally adapted, and sustainable water services are required. Collaborative efforts between First Nations authorities and federal, provincial, and territorial governments are imperative to ensure equitable access to safe drinking water in Indigenous reserves.

The Impact of Inter-Basin Water Transfer between Johor and Singapore on Johor’s Water Supply System, 1927 to 1941

Abstract Inter-basin water transfer between Johor and Singapore from 1927 to 1941 had a significant impact on Johor’s water supply system. This study aims to assess the consequences of this transfer and provide a contemporary perspective on its implications. Existing research on inter-basin transfers and their impact on water systems between Singapore and Johor is abundant, but there is a notable lack of research specifically addressing Johor’s water system during this time. By examining the historical context and socio-economic dynamics that shaped the inter-basin transfer, this study aims to contribute a unique perspective to the existing body of knowledge. The findings will enhance our understanding of the impacts of inter-basin water transfers and provide valuable insights for water resource management in the region. It also contributes to a comprehensive understanding of the impact of such transfers on contemporary water scarcity issues and provides practical insights for sustainable water resource management globally.

Metagenomic analysis of sedimentary archives reveals ‘historical’ antibiotic resistance genes diversity increased over recent decades in the environment

Abstract Antibiotic Resistance Genes (ARGs) are widespread in freshwater environments and represent a concealed threat to public health and aquatic eco-system safety. To date, only a limited number of studies have investigated the historical distribution of ARGs and their hosts through the analysis of freshwater sedimentary archives. This research gap constrains our comprehensive of the mechanisms underlying natural bacterial resistance formation during pre-antibiotic era (prior to the 1940s) and the development of human-induced bacterial resistance in post-antibiotic era (since the 1940s). In this study, we examined the vertical distribution patterns of ARGs and their associated hosts within a sedimentary core from a eutrophic lake, employing shotgun sequencing methodology. The findings revealed a marked increase in ARG diversity during post-antibiotic era, and the predominant ARG types identified included those conferring resistance to multidrug, bacitracin, macrolide–lincosamide–streptogramin, beta-lactam, tetracycline, fluoroquinolone, glycopeptide and aminoglycoside, collectively accounting for 78.3%–85.6% of total ARG abundance. A total of 127 ARG subtypes were identified in samples, and 48 ARG subtypes shared across vertical sediment resistome profile with two of them, bacA and bcrA, occurring only in post-antibiotic era. Further, 137 metagenome-assembled genomes (83 species belonging to 12 phyla) were identified as ARG hosts, mainly belonging to the phyla Proteobacteria, Nitrospirota, Chloroflexota, Bacteroidota, Actinobacteriota, Cyanobacteria, and Firmicutes. Significant correlation was found between the diversity of ARG and the concentrations of organic matter and heavy metals, suggesting a common source of contamination. Aside the fact that human-induced eutrophication is a forcing factor acting in parallel to increase ARGs releases in water systems, both being indicators of increased urbanization in the catchment, eutrophication may significantly increase bacterial activity, thereby facilitating the spread of antibiotic-resistant bacteria in environment. This study reveals the marked increased in ARG diversity with the onset of antibiotic use by human societies with potential impact of aquatic ecosystem.

An overview on the fate and behavior of imidacloprid in agricultural environments.

This review provides an overview on the fate and behavior of imidacloprid, a neonicotinoid insecticide, in agricultural environments. The study focuses on four key aspects: adsorption and leaching of imidacloprid in soil, degradation and hydrolysis of imidacloprid in soil and water, uptake and persistence of imidacloprid in plants, and volatilization of imidacloprid to the atmosphere. The review presents the latest findings from research on each of these topics. While imidacloprid is highly effective at controlling pests, it is also known to persist in the environment, posing risks to non-target organisms such as bees, birds, and aquatic life. Moreover, there is increasing concern about its potential to accumulate in the soil and water systems, which may have long-term effects on the ecosystem. The review suggests that better understanding of the behavior and fate of imidacloprid in agricultural environments is essential for developing effective strategies to minimize its environmental impact.

Study on the source identification and migration and transformation characteristics of heavy metal pollution in sediments of Chaohu Lake Tongyang River Basin.

Heavy metal pollution in soil and groundwater is difficult to detect in time because of its long-term accumulation. This poses a severe hazard to the ecosystem security in polluted areas. Considering the Tongyang River Basin of the Chaohu Lake water system as the research object, various pollution evaluation methods, Geographic Information System (GIS) source analysis models, adsorption and desorption experiments, and mathematical models were used. Based on the data of the heavy metal content in the soil and river sediments in the study area, regional heavy metal pollution evaluation, spatial distribution characteristics, source identification, and lake loss analysis were conducted to evaluate the current situation of environmental pollution, pollution sources, and migration and transformation of heavy metals in the basin. The results show that the heavy metals in the soil of the basin are mainly distributed from the southwest to the northeast and the island distribution to the east of Tongyang Town. The Cd, Cu, Zn, and Pb concentrations are higher in the sediment than in the soil. The Unmix analytical model was established. The natural source of heavy metals in the Tongyang River Basin and the composite pollution source of traffic-production and life showed a high correlation. According to the one-dimensional steady-state model, the concentrations of the heavy metals are in the following descending order: Zn, Cr, Pb, Cu, Ni, and Cd. The amounts of these elements entering the lake annually are 1993.04, 1028.1, 372.47, 301.72, 308.80, and 19.46 kg, respectively (a total of 4023.6 kg).

Influence of resins, asphaltenes and petroleum acid interactions on water/model oil interfacial properties and emulsion stability

The presence of natural lipophilic emulsifiers, such as asphaltenes (A), resin (R) and petroleum acids (PA) in crude oil, plays a crucial role in stabilizing the W/O emulsions. This study primarily focuses on elucidating the influence of their interactions on the interfacial properties of the water/model oil system, as well as its emulsion stability. First, equilibrium interfacial tension (IFT), interfacial dilational modulus (IDM) and phase angle are measured. Then, emulsion stability experiments are performed. Finally, microscopic images of the emulsions were captured to evaluate droplet size and dispersity. Results show that the addition of petroleum acid to both asphaltene-only and resin-only system reduces IFT and dilational modulus, weakening the strength of the interfacial film. The inhibitory effect of petroleum acid on resins’ adsorption at the interface is more pronounced compared to asphaltenes’. A low proportion of resin and petroleum acid (A/R ≥ 5, A/PA ≥ 7) enhances emulsion stability by co-adsorbing with asphaltenes at the oil–water interface. Conversely, a high proportion of resin and petroleum acid leads to a decrease in IDM and emulsion stability. For asphaltene/petroleum acid–water system, when A/PA ≤ 5, the presence of petroleum acid decreases the droplet size but enhances droplet dispersion while decreasing emulsion stability. It can be inferred that the presence of petroleum acids contributes more to the formation rather than stabilization of emulsions. This work deepens insights into the emulsion behavior of natural surfactants, providing theoretical guidance for the formation of stable emulsions underground and efficient demulsification above ground.

Weather conditions and legionellosis: a nationwide case-crossover study among Medicare recipients.

Legionellosis is a respiratory infection caused by Legionella sp. that is found in water and soil. Infection may cause pneumonia (Legionnaires' Disease) and a milder form (Pontiac Fever). Legionella colonizes water systems and results in exposure by inhalation of aerosolized bacteria. The incubation period ranges from 2 to 14 days. Precipitation and humidity may be associated with increased risk. We used Medicare records from 1999 to 2020 to identify hospitalizations for legionellosis. Precipitation, temperature, and relative humidity were obtained from the PRISM Climate Group for the zip code of residence. We used a time-stratified bi-directional case-crossover design with lags of 20 days. Data were analyzed using conditional logistic regression and distributed lag non-linear models. A total of 37883 hospitalizations were identified. Precipitation and relative humidity at lags 8 through 13 days were associated with an increased risk of legionellosis. The strongest association was precipitation at day 10 lag (OR = 1.08, 95% CI = 1.05-1.11 per 1 cm). Over 20 days, 3 cm of precipitation increased the odds of legionellosis over four times. The association was strongest in the Northeast and Midwest and during summer and fall. Precipitation and humidity were associated with hospitalization among Medicare recipients for legionellosis at lags consistent with the incubation period for infection.

Computer-based monitoring system of retort processes for energy efficiency and carbon emission reduction

Retort sterilization is critical in the food industry. However, retorts are not smart enough to fully monitor and calculate their energy usage to reduce their carbon emissions. In this project, sensors and network equipment were installed in a retort, and a PC-based system was used to process the collected data. To monitor the sterilization status and energy consumption, we added flow sensors and electricity meters and built a visual identification system. Carbon emissions were calculated, and energy conservation and carbon emission reduction strategies were explored. According to the monitoring data, the electricity consumption of the air compressor, boiler, and natural gas combustion accounted for 80 % of the total carbon emissions. If the equipment cannot be changed, the cooling water system can be stopped in noncooling stages to conserve energy. This strategy reduced the energy consumption of the cooling system by 70 % and was the most effective strategy for this project.

Metal and metal oxide nanomaterials for heavy metal remediation: novel approaches for selective, regenerative, and scalable water treatment

Heavy metal contamination in water sources poses a significant threat to environmental and public health, necessitating effective remediation strategies. Nanomaterial-based approaches have emerged as promising solutions for heavy metal removal, offering enhanced selectivity, efficiency, and sustainability compared to traditional methods. This comprehensive review explores novel nanomaterial-based approaches for heavy metal remediation, focusing on factors such as selectivity, regeneration, scalability, and practical considerations. A systematic literature search was conducted using multiple academic databases, including PubMed, Web of Science, and Scopus, to identify relevant articles published between 2013 and 2024. The review identifies several promising nanomaterials, such as graphene oxide, carbon nanotubes, and metal-organic frameworks, which exhibit high surface areas, tunable surface chemistries, and excellent adsorption capacities. Surface functionalization with specific functional groups (e.g., carboxyl, amino, thiol) significantly enhances the selectivity for target heavy metal ions. Advances in regeneration strategies, including chemical desorption, electrochemical regeneration, and photocatalytic regeneration, have improved the reusability and cost-effectiveness of these materials. Scalability remains a critical challenge, but recent developments in synthesis methods, such as green synthesis and continuous-flow synthesis, offer promising solutions for large-scale production. The stability and longevity of nanomaterials have been improved through surface modification and the development of hybrid nanocomposites. Integrating nanomaterials with existing water treatment infrastructure and combining them with other remediation techniques, such as membrane filtration and electrochemical methods, can enhance overall treatment efficiency and feasibility. In conclusion, nanomaterial-based approaches hold immense promise for revolutionizing heavy metal remediation and advancing sustainable water management practices. As future research is geared towards retrofitting existing treatment plants, it is equally critical to mitigate unintended environmental and public health consequences associated with the widespread production and use of nanomaterials, such as their leachability into water systems and environmental persistence.

Legionella in Primary School Hot Water Systems from Two Municipalities in the Danish Capital Region.

Legionella contamination in public water systems poses significant health risks, particularly in schools where vulnerable populations, including children, regularly use these facilities. This study investigates the presence of Legionella in the hot water systems from 49 primary schools across two municipalities in the Danish capital region. Water samples were collected from taps in each school, and both first-flush and stabile temperature samples were analysed for Legionella contents. The findings revealed that 97% of schools in Municipality 1 and 100% in Municipality 2 had Legionella in their hot water systems. The content of Legionella colonies was significantly higher in schools in Municipality 1, which was probably because of overall lower water temperatures. At stabile temperatures, 76% and 50% of the schools in the two municipalities exceeded the European Union's recommended limit of 1000 CFU/L. Stabile peripheral water temperatures were achieved after 3 min. Tap water temperatures above 54 °C and central tank temperatures above 59 °C were associated with Legionella contents below 1000 CFU/L. This study highlights the need for more stringent Legionella control procedures in schools, including higher water temperatures and refining Legionella reducing interventions with the addition of regular flow and draining procedures.

Ultrasonication-Boosted Resorcinol-Formaldehyde Resin Nanoparticle Bromine Fixation and Corresponding Upgraded Aquatic Applications.

Bromine (Br2) and related species removal from water systems are rather complicated due to the complicated chemistry instability, and materials with high Br2 removal rate and efficiency, along with stimuli/apparatus suitable for highly corrosive environments, are necessary. Ultrasonication as a non-destructive process is especially suitable in scenarios where conventional stir apparatus is not applicable, such as highly corrosive environments. Considering the validity nature of Br2 and combining the advantages of ultrasonic with a highly stable Br2 fixation method through aromatic polymer nanoparticles, we demonstrate highly efficient acoustic-aided Br2 removal in aqueous solutions with two times capacity compared to the non-treated sample. Related aquatic applications are also proposed for the materials to be cost-effective, including silver (Ag) recovery, recyclable MnO2-mediated Br2 deep removal, and aqueous zinc anode modification. The coupled novel-material-based processes motivate the strategic design of water purification with high-safety and sustainable industrial procedures and post-value-added utilizations.

Transition from endogenous to exogenous feeding in longfin yellowtail Seriola rivoliana larvae under simultaneous effects of daily temperature fluctuation and rotifer Brachionus rotundiformis enrichment.

Temperature and nutrition are suggested as the primary factors affecting larval survival during the transition from endogenous to exogenous feeding in fish. However, little is known about its simultaneous impact during this period. In this study, Seriola rivoliana eggs were subjected to a constant 24°C (CTE) and a daily temperature fluctuation (DTF) between 22.8 and 25.2°C until oil droplet exhaustion (5.5days after hatching). On the other hand, marine fish larvae mostly rely on live feed, with certain nutritional deficiencies such as poor long-chain fatty acids. Thus, rotifer Brachionus rotundiformis enrichment was simultaneously evaluated with temperature using three enrichment diets: Ori-green, S.presso, and a Domestic emulsion. For this purpose, the five experimental groups were established in triplicate using six 100-L tanks with three 10-L containers inside (18 experimental units in total). One hundred eggs were incubated, using a green water system, and 10 rotifers mL-1 were offered at mouth opening. After oil droplet exhaustion, survival was only affected by temperature (P < 0.01), being higher at DTF compared to CTE. At the same stage, Domestic emulsion resulted in bigger larvae than Ori-green. In a further assay at 3.7 DAH, the relative expression of the trypsin gene was higher at Domestic emulsion compared to S.presso and Ori-green. This study indicates that daily temperature fluctuation can improve larval performance and low levels of EPA and DHA in Domestic emulsion enriched rotifers were not critical for Seriola rivoliana at first feeding.

Department-specific patterns of bacterial communities and antibiotic resistance in hospital indoor environments

The hospital indoor environment has a crucial impact on the microbial exposures that humans encounter. Resistance to antibiotics is a mechanism used by bacteria to develop resilience in indoor environments, and the widespread use of antibiotics has led to changes in the ecological function of resistance genes and their acquisition by pathogens. By integrating the 16S rRNA Illumina sequencing and high-throughput-quantitative PCR approaches with water and air dust samples across seven departments in Peking University Shenzhen Hospital, China, this study yields intriguing findings regarding the department-specific variations, correlations and source tracing of bacteria, antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) within the hospital indoor environment. A notable observation was the pivotal role played by seasonal variations in shaping the bacterial composition across the entire hospital indoor environment. Another department-specific finding was the correlation between ARGs and MGEs abundance, which was evident in the overall hospital indoor environment, but not found in the blood test room, ophthalmology, and gynecology departments. Notably, as an important source of bacteria and ARGs/MGEs for the blood test room, the gynecology department also presented a close link between bacterial communities and the presence of ARGs/MGEs. Additionally, the results reiterate the importance of surveillance and monitoring of antibiotic resistance, specifically in Legionella spp. in man-made water systems, and highlight the significance of understanding genetic elements like Tp614 involved in gene transfer and recombination, and their impact on antimicrobial treatment efficacy. Key points•The department-specific variations, correlations and source tracing of bacteria, ARGs, and MGEs were uncovered in the hospital’s indoor environment.•Although each department exhibited consistent seasonal impacts on bacterial compositions, the co-occurrence between the presence of ARGs and MGEs was exclusively evident in the emergency, surgery, pneumology and otolaryngology departments.•The gynecology department emerged as a crucial source of bacteria, ARGs and MGEs within the hospital. Additionally, it was found to exhibit a significant correlation between bacterial communities and the presence of ARGs and MGEs.

Water tariffs and social equity: Towards water service connections and pricing instruments for the poor

AbstractAside from operational sustainability and efficiency goals, water tariffs also need to address the requirements of affordability and equity, in most instances, by providing subsidies to poor households. Yet, poor households are unable to enjoy the benefits of such cross‐subsidization and linked conveniences as they are unable to get water service connections. Even with a well‐designed water tariff, the inability of poor households to get piped connections results in the payment of premiums for water that is difficult to access and, at times, of questionable quality. In this paper, we assess the pro‐poor projects of three Philippine municipal water systems and suggest that providing water service connections to poor households allows these households to avoid paying the water poverty premium, as well as experience the related public health and quality of life benefits accruing from such connections. We argue that designing the best tariff for existing socio‐economic, political, and environmental realities must go hand in hand with programs that provide water service connections to poor households as this will ensure not only operational viability but also equitable water provision.

Predicting Accumulation and Potential Edge-of-Field Loss of Phosphorus to Surface Water from Diverse Ecosystems

Phosphorus (P) is an important nutrient essential for agricultural production, but it is highly reactive, leading to its soil accumulation and making it susceptible to environmental impact footprints. The goal of our study was to determine the critical threshold values of both soluble reactive P (SRP) and oxalate-extracted P (Ox-P) to predict soil P accumulation and its susceptibility to edge-of-field loss. Composite soils were collected from geo-referenced ecosystems within the Lake Erie drainage basin under agriculture in northwestern Ohio, USA. Soils were analyzed for SRP, Ox-P, Fe, and Al concentrations to calculate P sorption capacity, P saturation ratio, degree of P saturation (DPS), and P storage capacity (SPSC). A threshold P saturation ratio of 0.12 (~ 24% DPS), corresponding to 2.4 mg SRP/kg (equivalent Ox-P), was determined to calculate SPSC for predicting the risk of SRP accumulation. A significant relationship between the SPSC and SRP suggested that soils under all the agroecosystems had accumulated SRP compared to the forest. Surface soils (0–10 cm depth) under tilled, chemically fertilized, and organically managed corn (Zea mays)-soybean (Glycine max (L) Merr.) rotations, including those treated with chicken and dairy manure, exhibited excessive SRP accumulation, making them susceptible to edge-of-field losses. While the soils at 10–20 cm depth were acting as transitional, the deeper soils (20–30 cm depth) still acted as a net sink. When accounting for bulk density to calculate SPSC stocks, it showed that surface soils across the agroecosystems were saturated with 148 to 240 kg SRP/ha and were susceptible to edge-of-field loss to the water systems. In conclusion, we suggest that SPSC could be used as an early indicator to predict the risk of SRP accumulation and its potential edge-of-field loss to Lake Erie from agroecosystems.

Evaluation of spatial form and activation strategies of traditional villages using spatial information technology

Traditional villages are important carriers of regional cultural inheritance. The challenge of utilizing spatial information technology to protect and preserve the architectural spatial patterns and regional context of traditional villages has attracted significant attention. This study focuses on Biasha Miao village in Guizhou province, China, as the case study. Digital information technology was used to evaluate the architectural spatial texture and typical street space characteristics of different villages. Using the DepthMap model of space syntax and parameters such as integration, average depth value, and connectivity, the article examines the spatial form of traditional villages across three aspects: overall space, street space, and point-like public space. In the end, a spatial activation optimization strategy was proposed. The results showed that the spatial layout of buildings in different villages is closely related to the distribution characteristics of landscape elements such as landform, water system, and farmland, as well as residents&amp;rsquo; production, lifestyle, and regional culture. Da village and Zaige new village are well-connected to the main traffic roads connecting them to the outside world, resulting in high spatial permeability and a more extroverted spatial development. Most public spaces are located near the main village road, offering good accessibility, or at the geometric center of the village, where they serve critical roles in cultural display and distribution. This study proposes targeted activation strategies focusing on road traffic, street layout, and spatial nodes to optimize and enhance the spatial quality of traditional villages, improve residents&amp;rsquo; living environments, and provide practical guidance for the sustainable development of traditional village spaces.

Disconnected Flows, Eroded Landscapes: A Case Study of Human Impact on a Judean Desert Water System

The Bir el-Umdan cistern, a prominent archaeological site in the Judean Desert, is one of the largest and best preserved water systems in the region. Hewn in chalk, the cistern area measures 114 m2 and has a ~700 m3 volume. Two massive columns, each with a base diameter of 2.5 m, support the ceiling within the cistern’s interior. This impressive structure is estimated to date back to the Hellenistic to Late Antiquity periods based on its architectural characteristics. Historical records indicate that the cistern was documented on 19th-century maps but disappeared from the 1935 and 1943 British Mandate maps. Its reappearance on the 1967 Survey of Israel map includes an upstream road disconnecting the cistern from its natural drainage basin. Despite its renovation in the 2010s, the cistern’s water supply remains limited due to its reduced catchment area, which now constitutes only 25% of its original size. Runoff coefficients calculated for the cistern’s drainage basin are relatively low (1.4% to 8.1%) compared to other desert regions. We analyzed the 21st-century runoff coefficient and recurrence interval over the original drainage basin (0.12 km2) to estimate the water volumes in antiquity. Our analysis suggests that using an 8.1% runoff coefficient, the estimated water volume is 806 m3, implying a cistern overflow every 6–7 years. A more conservative estimate using a 5% runoff coefficient yields a water volume of 500 m3 and a 15-year recurrence interval. Sediment analysis reveals that silt particles dominate the sediment accumulated in the cistern and its upstream sedimentation basins. The consistent grain size distribution throughout the system indicates rapid water flow during flood events. Reconstructing the sedimentation history is challenging due to potential maintenance and possible dredging and cleaning operations.

The effect of the molting cycle on the acoustic characteristics of clicks emitted by Litopenaeus vannamei

In penaeid shrimp, the mandibles are responsible for emitting click sounds when they collide during food intake, which has been used to assess feeding activity by passive acoustic monitoring. However, the acoustic parameters of the clicks could be affected by variations in the thickness of mandible cuticle during the molting cycle. Thus, the aim of this study was to evaluate the effects of the molting cycle on the acoustic characteristics of clicks emitted during the feeding activity of Litopenaeus vannamei fed commercial pelleted diet. Shrimp with an average weight of 8.75 ± 1.05 g were individually maintained in 24 tanks in a recirculating water system. A total of 12 animals had their feeding activity individually recorded soon after ecdysis (postmolt group), while another 12 were recorded in the middle of their molting cycle (intermolt group). Recordings took place in anechoic chambers with a hydrophone connected to a digital recorder (sampling rate of 192 kHz), and the click acoustic parameters were characterized in Raven® 1.5 Pro software. After the recordings, the shrimp had their mandibles removed for length measurement and histological analysis of the mandibular cuticle. Body (weight and length) and mandibular measurements did not differ between shrimp groups, but those in the postmolt stage showed significantly lower cuticle thickness. The acoustic characteristics of the clicks were affected by shrimp molting stages, with significantly lower maximum energy (dB) and maximum frequency (kHz) in postmolt shrimp, probably related to their lower mandibular cuticle thickness. These results may contribute to the assessment of shrimp feeding behavior associated with the molting cycle, as well as to the optimization of algorithms controlling acoustic automatic feeders in farming systems.