Volume Of Water Research Articles

Lacidipine, thiamine pyrophosphate and their combination on the ocular ischemic syndrome induced by bilateral common carotid artery ligation

AIM: To investigate the effect of lacidipine, thiamine pyrophosphate (TPP) and the combination of lacidipine and TPP against oxidative and inflammatory eye damage induced by bilateral common carotid artery ligation in rats. METHODS: Male albino Wistar rats were categorized as those who underwent sham surgery (SG), right and left common carotid cross-clamping and unclamping procedure (CCU), lacidipine+CCU (LCCU), TPP+CCU (TCCU), and combination of lacidipine and TPP (LTC)+CCU (LTCCU). One hour before anesthesia, the LCCU (n=6) received lacidipine (4 mg/kg, orally) and the TCCU (n=6) received TPP (20 mg/kg, intraperitoneally). The SG (n=6) and CCU (n=6) received the same volume of distilled water from the same route. After anesthesia (60 mg/kg ketamine, intraperitoneally), the necks of the rats were opened in the midline. Ischemia was created for 10min by placing clips on the right and left common carotid arteries. Rats in the SG only underwent subcutaneous incision. After 10min, the clips were removed and reperfusion was achieved for six days. Then, the animals were euthanized (120 mg/kg ketamine, intraperitoneally) and the levels of oxidant, antioxidant and proinflammatory cytokines in the eye tissues were determined. The retinal tissue of the eye was also examined histopathologically. RESULTS: Lacidipine, TPP, and LTC significantly prevent the increase in malondialdehyde, tumor necrosis factor-alpha, interleukin-1β (IL-1β), and IL-6 levels, decrease in total glutathione levels, superoxide dismutase and catalase activities and histopathological retinal damage in eye tissue induced by bilateral common carotid artery ligation in rats. The impact of these drugs on protection is determined to be LTC>lacidipine>TPP. CONCLUSION: As a result of the study, it is concluded that LTC may be more effective than lacidipine and TPP alone in treating ocular ischemic syndrome.

Improving mangoes' productivity and crop water productivity by 24-epibrassinosteroids and hydrogen peroxide under deficit irrigation

In nature, plants are frequently subjected to a wide range of abiotic stresses that drastically reduce crop productivity. Deficit in irrigation is one of the main factors of abiotic stresses that affect agricultural productivity. Nevertheless, not much research has been done on how to use water with brassinosteroids (Br) and hydrogen peroxide (H2O2)in deficit water conditions in order to reach comparatively good values of mango tree growth, productivity, and fruit quality as well as crop water productivity (WPC). A split-plot experiment in a complete randomized block system design study with 3 regulated deficit irrigation levels i.e. 100% IR (Irrigation requirement), 80% IR, and 60% IR was implemented in 2022 and 2023, each irrigation regime was combined with the foliar application of distilled water (control), 1 mg/L Br, 10 mM H2O2, 1 mg/L Br + 10 mM H2O2. Foliar treatments were applied at 3 different phenological stages: flower bud induction and differentiation, full bloom, and beginning of fruit set. The results showed that fruit shape index and acidity significantly improved as irrigation volume increased, however, the proportion of fruit mineral content and fruit chemical characteristics was inversely correlated with the volume of water. Meanwhile, moderate regular deficit irrigation (80% IR) achieved marked increases in leaf minerals and total chlorophyll content, fruit quality, yield, and water use efficiency. Drought stress (60% IR) significantly decreased fruit set, fruit retention, yield traits, and fruit physical and chemical properties, at the same time, significant improvements in the content of stress indicators (proline, total phenols, and carotenoids) were observed compared with control. All treatments with Br and H2O2 alone or in combination under drought stress had a pronounced effect in this regard. Overall, foliar spray of 1 mg/L Br+10 mM H2O2 was the most powerful treatment that emended the unpropitious effect of water stress.

Towards non-invasive tissue hydration measurements with optical coherence tomography.

The attenuation coefficient ( ) measured by optical coherence tomography (OCT) has been used to determine tissue hydration. Previous dual-wavelength OCT systems could not attain the needed precision, which we attribute to the absence of wavelength-dependent scattering of tissue in the underlying model. Assuming that scattering can be described using two parameters, we propose a triple/quadrupole-OCT system to achieve clinically relevant precision in water volume fraction. In this study, we conduct a quantitative analysis to determine the necessary precision of measurements and compare it with numerical simulation. Our findings emphasize that achieving a clinically relevant assessment of a 2% water fraction requires determining the attenuation coefficient with a remarkable precision of 0.01 . This precision threshold is influenced by the chosen wavelength for attenuation measurement and can be enhanced through the inclusion of a fourth wavelength range.

Impact of Fruit Load on the Replenishment Dynamics of Internal Water Reserves in Olive Trees

Stem refilling has been studied in many forest species, but its impact on olive trees remains underexplored. This study aims to examine the effect of varying fruit loads on stem refilling rates in olive trees. The experiment was conducted in a commercial olive orchard over two years, characterized by a biennial bearing cycle with minimal fruit production in 2021 (“OFF” year) and maximal fruit production in 2022 (“ON” year). Sap flow sensors measured the water volume differences traversing the apex and base of main branches in two experimental trees. Tree water status was monitored using psychrometers, and soil moisture content was continuously recorded. Results suggest that alternate bearing significantly affects the stem refilling process, while soil moisture availability also plays a pivotal role. During the “ON” year, water reserve consumption increased to 63.6% compared to the “OFF” year to meet the water requirements of developing fruits. Replenishment occurred at various times throughout the 24 h period, including early morning, afternoon, and night when stomatal conductance measurements indicated stomatal closure. During the “ON” year, olive trees experienced intense nocturnal replenishment of reserves, regardless of soil moisture, water vapor pressure deficit, or fruit development stage. These findings offer novel insights into olive trees’ rehydration dynamics that can be used to optimize irrigation scheduling and improve water use efficiency.

The Potential use of Reclaimed Water for Irrigation Purposes: Is it Overestimated?

AbstractThe use of reclaimed water is expected to increase in the coming years, mainly in water-scarce areas. In the European Union (EU), an increase in the use of reclaimed water is expected to play a significant role within the European circular economy strategy and climate change adaptation policies with the aim to enhance overall sustainability of water resource management. While several institutions have offered estimations of the potential of reclaimed water reuse in the EU context, these estimations tend to overestimate potential reuse volumes since they fail to fully consider the following important issues: (a) the role of return flows in basins where cascade reuse is crucial in maintaining downstream uses (including ecological flows); (b) the availability of abundant (and cheaper) conventional resources; and (c) the economic productivity of water as an indicator of users’ willingness to pay for reclaimed water. This study focuses on the Spanish case since this is currently the EU member state with the highest potential for reclaimed water reuse. Findings show that previous estimations of reusable water volumes in Spain may have overestimated potential volumes. The proposed analysis can be extrapolated to other EU regions, where realistic estimations of the potential of reclaimed water might be much needed.

The influence of the Black Sea rim current and the coastal quasi-stationary anticyclonic Eddie on the distribution of ichthyoplankton and jellyfish

This article describes the Black Sea quasi-stationary coastal anticyclonic eddy (CAE), with large accumulations of zooplankton and ichthyoplankton, which were registered in August 2021 off the northeastern Black Sea during the period of a tropical-type atmospheric mesocyclone. Intense rains (60–80 millimeters of precipitation) caused flooding and large volumes of terrestrial water entered the sea. Water flows came from rivers into the coastal area and flowed into the CAEs. As a result, there were favorable conditions for the growth of plankton, fish eggs and, larvae. Thus, in the Sochi CAE, against the background of a high concentration of chlorophyll a, and the abundance of small-sized fractions of the fodder zooplankton, there was an almost 30-fold increase in the number of fish larvae (947 ind.·m−2 in the CAE and 33.5 ind.·m−2 in the surrounding waters) and the accumulation of jellyfish Aurelia aurita (Linnaeus, 1758), which is their food competitor, with an abundance of up to 44 ind.·m−2. The data obtained indicates that the Black Sea coastal quasi-stationary anticyclones arise between the cyclonic rim current (Main Black Sea current) and the coast, which can be of great importance in the formation of fish abundance.

Inhibitors application time and pasture canopy capture regulate gaseous losses of urine-N

AbstractTechnologies have been developed for the in-situ treatment of urine patches deposited by grazing livestock to mitigate nitrogen (N) losses using N transformation inhibitors. For this mitigation to be effective, close contact between the applied inhibitors and the N in the urine patch is required (similar to N-fertilisers coated with inhibitors). This research aimed to determine the proportions of urine-N that mixed with inhibitor at or exceeding the threshold concentration (inhibitor concentration at which the nitrification rate is reduced by at least 40%) when inhibitors were applied to simulated urine patches at 4, 24 and 48 h after synthetic urine application. Three commonly used nitrification inhibitors (NIs) [dicyandiamide (DCD), 3,4-dimethylpyrazole phosphate (DMPP), and 2-chloro-6-(trichloromethyl) pyridine (nitrapyrin)] were applied at 40 mL of inhibitor per urine-patch at two different concentrations. The field studies were undertaken in two dairy-grazed pasture soils with contrasting drainage. Large proportions of applied NIs (38%–59% DCD, 27%–58% DMPP, and 31%–58% nitrapyrin) were retained in the pasture canopy. In most cases, the inhibitor threshold concentration was present only within the top 0–20 mm of the soil, with only 16%–40% of the urine-N present. In some cases, the proportions of urine-N intercepted was 12%–15% higher when inhibitors were applied 4 h after urine application compared to delayed application of 24 and 48 h after urine application. Our results revealed that a substantial proportion of N in the urine-patch remained out of the reach of the inhibitor solution. This is possibly due to the small volume (40 mL per 2 L urine patch, 1:50) of the inhibitors applied, with up to 59% of inhibitor solution retained in the pasture canopy. The time delays (4 to 48 h) between the urine deposition and the inhibitor application could have also contributed to this poor physical mixing between inhibitor and urine. Increasing the volume of water applied with the inhibitor and assessing the effect of rainfall/irrigation on increasing urine-N and inhibitor mixing warrants further consideration.

Cellulose-Based Hydrogels for Wastewater Treatment: A Focus on Metal Ions Removal.

The rapid worldwide industrial growth in recent years has made water contamination by heavy metals a problem that requires an immediate solution. Several strategies have been proposed for the decontamination of wastewater in terms of heavy metal ions. Among these, methods utilizing adsorbent materials are preferred due to their cost-effectiveness, simplicity, effectiveness, and scalability for treating large volumes of contaminated water. In this context, heavy metal removal by hydrogels based on naturally occurring polymers is an attractive approach for industrial wastewater remediation as they offer significant advantages, such as an optimal safety profile, good biodegradability, and simple and low-cost procedures for their preparation. Hydrogels have the ability to absorb significant volumes of water, allowing for the effective removal of the dissolved pollutants. Furthermore, they can undergo surface chemical modifications which can further improve their ability to retain different environmental pollutants. This review aims to summarize recent advances in the application of hydrogels in the treatment of heavy metal-contaminated wastewater, particularly focusing on hydrogels based on cellulose and cellulose derivatives. The reported studies highlight how the adsorption properties of these materials can be widely modified, with a wide range of adsorption capacity for different heavy metal ions varying between 2.3 and 2240 mg/g. The possibility of developing new hydrogels with improved sorption performances is also discussed in the review, with the aim of improving their effective application in real scenarios, indicating future directions in the field.

Industrial-Based GSM Water Leakage Detection, Monitoring and Controlling System: A case of North Rift Valley Water Agency in Kenya

The current system for detecting and monitoring water leaks in Kenyan industries is manual and costly. Despite emerging new technological trends, many industries lack automated systems to detect, monitor, and control water leakage due to the high cost of maintenance and installation. This study's objective was to develop an automatic, remote, and real-time detection, monitoring, and, control system for water leaks. The system is made up of two nodes, one at the source and one at the destination or tap. The two nodes are made up of an ESP microcontroller, which is used to control all the connected components. The use of the ESP 32 microcontroller was efficient due to its ability to provide WI-FI. Aside from the solenoid valve, which was used to turn the water flow on or off in the event of leaks, the system also includes the FY-201 water flow sensor, which was used to gauge the amount of water flowing through the pipe. Water leakage is detected when the volume of water passing through the two sensors differs in terms of volume, indicating that a water leakage has just occurred. Thing-Board, an IoT-based platform used to monitor and visualize data from various devices connected, was used for real-time monitoring, visualization, and control. The developed system was tested with different water service providers, and the results showed that the system responds positively to water leakage parameters with capability of monitoring water leakages in a real time.

Impact of efficiency on affordability: A study of the Brazilian new water loss goals

ABSTRACT Infrastructure service affordability has become a burgeoning concern over the past years due to the recent economic crisis and the growing role of tariffs in funding the services. Pressure on utilities to promote social assistance programs in addition to an efficient service has risen toward providing water as affordable as possible. This study shows the positive impact of efficient services on families' water affordability by analyzing the new Brazilian water loss goals and the potential effect of water loss reduction on total expenses reported in the Brazilian utilities' National Water and Sanitation Information System (SNIS). The total service cost for water and sanitation (before and after the aforementioned goals) was then translated to average tariff per cubic meter and affordability ratios. The potential water volume saved in physical losses can reach up to 16.6% of the water consumed in the country, and although the impact on water affordability was timid, the positive results indicate utilities have an important role in assuring water and sanitation for all, and regulators must be involved toward taking a deep look at local conditions.

Water-energy trajectories for urban water and wastewater reveal the impact of city strategies

The global water industry has a greater emphasis on energy management than ever before. The confluence of rising energy demand and costs, and net-zero greenhouse gas emission targets means the sector must rapidly transition to a new ‘energy future’. Yet, few cities have assessed the long-term energy use of their water and wastewater systems. Here, we undertake a novel and integrated assessment of the historical trends of energy use for water and wastewater in three Australian and two US cities, collectively 17 million people. The key research question is what were the historical trends of energy use for water supply and wastewater treatment, and what can we understand about the drivers? The research contributes a first systematic time-series assessment of energy trajectories of both water and wastewater, across multiple cities. Uniquely, it integrates long-term (up to 20 years) energy dynamics in a comparative analysis. The work also contributes a qualitative analysis of driving factors behind the observed energy variations. The time-series analysis (2001−2020) identifies how energy use is evolving through time in widely differing climate, urban and water infrastructure conditions. The cities studied demonstrated downward trends in water use by 30–42% and wastewater collected by 5–30%, primarily due to water conservation and drought-related restrictions. Annual per-capita energy use for water supply reduced in Los Angeles (−58%, from 276 to 116.5 kWh/p/a), San Diego (−59%, from 503.7 to 204.2 kWh/p/a), Sydney (−26%, from 40.6 to 30.1 kWh/p/a) and increased in Melbourne (+859%, from 15.7 to 150.6 kWh/p/a) and Perth (+139%, from 118.1 to 281.9 kWh/p/a). Compared to water supply, energy use for wastewater was far more stable (it varied between 45 and 85 kWh/p/a), and not the crucial contributor to overall energy use dynamics. The significant increase in seawater desalination is identified as the primary driver of increased energy use in the three Australian cities. To offset this huge demand, developing renewable energy generation emerged as the key strategy. It causes high fluctuation of renewable energy use shares (Sydney: 317 GWh, accounting for 48.5% energy use for water and wastewater in 2011; compared to 19 GWh, accounting for only 2.5% in 2008). In contrast, both Los Angeles and San Diego managed to considerably reduce energy use by decreasing their imported water volume and energy intensity (the result of an adjusted supply portfolio). However, the absence of consistently comprehensive water/energy/renewable energy data remains a significant hurdle for a thorough quantitative analysis of drivers. Given these observations, it is evident that detailed quantitative analysis for influencing factors (e.g. water use, climate, infrastructure upgrading, sustainability targets), requires separately reported energy use for both water supply and wastewater, reported water from categorized sources and significant other data. By addressing these issues, we can have a clear path towards an energy-efficient, sustainable urban water system with net-zero emissions.

A review of the benefits and limitations of waste nutrient treatment in aquaculture pond facilities

AbstractManaging waste nutrients from intensive freshwater and marine pond aquaculture is a global challenge. Nutrient‐enriched water released from farms can have detrimental effects on aquatic ecosystem health. There are a range of treatment options for discharge water from fish and crustacean ponds, and this review examines the benefits and limitations of these options. Much of the nutrient waste is derived from the addition of formulated feed. In recent years, reduction in waste from feeds and feeding has been largely incremental. In terms of treatment, there are low‐cost approaches, such as settlement ponds, but they are inefficient at reducing nutrients. Biological systems, using aquatic plants, microalgae and filter feeders to reduce nutrient release from farms have variable levels of effectiveness. Establishing wetlands requires considerable additional land area, and success to date has been highly variable. Overall, this review found no simple cost‐effective solution for managing nutrient enriched water from ponds. This is due, in many cases, to challenges with treating the large volumes of discharge water with relatively low nutrient concentrations. This means that more technologically advanced and reliable treatment options, for example, bioreactors, are prohibitively expensive. However, some systems, such as use of recirculation systems typically increase nutrient concentrations, and hence the efficiency and effectiveness of more expensive treatment methods. Biofloc systems can also provide a mechanism for in‐situ nutrient treatment as well as a supplementary food source for animals. Overall, there is scope to improve treatment of waste nutrients, but significant modifications to many production systems are needed to achieve this.

Water Transfer Energy Efficiency Index for inter‐basin water transfer projects

AbstractInter‐basin water transfer projects (WTPs) address water scarcity by lifting water uphill, posing energy challenges due to diverse topography. This study therefore analyses historical trends in WTP distance, average annual water volumes delivered, water lift and pumping capacity to develop the Water Transfer Energy Efficiency Index (WTEEI) and apply it for the assessment of WTPs. Results indicate that the WTEEI is a valuable tool for evaluating WTP energy efficiency. While no definitive trend in WTEEI values was observed, the findings suggest the need for monitoring of energy use of WTPs and more research to better understand and improve the energy efficiency of these large‐scale infrastructure projects. By introducing a simple, intuitive and rapid assessment tool for evaluating energy efficiency in WTPs, this study addresses a critical gap in the water–energy field, namely, the evaluation of energy usage in WTPs and the identification of energy‐efficiency improvements for current and future WTPs.

Technological Parameters of Microfiltration in the Production of Micellar Casein Concentrate

Background:: There are many different factors that influence the process of microfiltration, including membrane pore size, pressure, temperature, and membrane origin. Studying the joint influence of technological parameters in order to justify rational modes of microfiltration is relevant. Objective:: This research aimed to define the rational technological parameters of microfiltration, which allow to achieve the target parameters of retentate in the process of obtaining micellar casein concentrate. Methods:: Standard and modified methods and techniques have been used in the process of experimental research. The mathematical processing was carried out by methods of mathematical statistics according to several trials data at three stage sequence. Results:: As a result of experimental investigations, the applicability of ceramic membranes for microfiltration of skim milk has been shown. The rational pore size has been established as 0,1 μm. To obtain the micellar casein concentrate, it is advisably to carry out the microfiltration of skim milk to the mass fraction of dry solids in concentrate (13 ± 3) %, followed by two-phase diafiltration with a double volume of reverse osmosis water. The rational operating conditions, allowing to get the target value of protein fractions correlation, have been established, as described as follows: input pressure as 0,2 – 0,3 MPa, and temperature as 10 – 15°С. Conclusion:: The analysis of microfiltration concentrates and permeates composition of raw milk, including vitamins and minerals content, showed both their high nutritional and biological value and the viability of further processing into food ingredients, including the ingredients for the specialized food products.

PROTOTYPE OF FLOOD EARLY WARNING SYSTEM (EWS) USING TELEGRAM BROADCAST MESSAGE NOTIFICATION

Flooding has until now become a serious problem in various regions in Indonesia. Flooding is a problem that occurs due to increasing the volume of excess water in rivers that are influenced by human activities that are not friendly to the environment. Floods have quite a lot of negative impacts, one of which is the damage to community facilities and infrastructure. Community preparedness is needed to reduce the negative impact of the flood. One solution that can be done is to design a flood Early Warning System (EWS) as a tool in detecting water levels before the arrival of flood hazards. Mitigation activities need to be complemented by a monitoring system based on the environmental conditions of the surrounding community. This research aims to make a prototype of a flood early warning system that is easy to operate and effective to detect the arrival of floods. In the prototype there is a level switch sensor that can detect high movements of water levels in the watershed. High level information on the water level is then sent periodically in the form of notifications via telegram to the smartphones of community residents whose numbers are registered in the system. From the test results, the ultrasonic sensor obtained 98.7% read accuracy results and a delay time in sending telegram notifications of 3-5 seconds.

Slope Stability Monitoring of Hydroelectric Dam and Upstream Watershed Areas Utilizing Satellite Interferometric Synthetic Aperture Radar (InSAR)

Dams offer significant benefits such as power generation, flood control, irrigation, and tourism. However, when mismanaged, they pose a high risk of catastrophic failure, potentially releasing large volumes of water rapidly, resulting in severe downstream damage, environmental impacts, injuries, and loss of lives. Effective dam monitoring is essential to evaluate slope stability, detect slope behaviour changes, and deliver early warning for potential hazards. Upon detecting any deformations in the dam or its watershed areas, prompt interventions can be initiated. Interferometric Synthetic Aperture Radar (InSAR) is the measurement technique of signal phase change between two images at the same location and at different times, it will be a proficient method for monitoring ground or slope changes across vast areas without the installation of on-site instrumentation. The dataset used in this work consists of 392 images of Sentinel-1 from 1 September 2018 to 11 August 2023 to conduct long-term InSAR data analysis. Monitoring the dam and its watershed is crucial, given that over 30% of U.S. dam failures result from overtopping. Slope failure events at the upstream area can cause abrupt water level rises, further increasing the risk of overtopping and major instability. This study explores slope deformation around dams and their watersheds using satellite long-term InSAR technology using a study case from one of the dams in Indonesia. The outcomes will provide insights into dam safety and shed light on the strengths and constraints of the InSAR technology.

Effect of geometry on the coefficient of performance of Ni-Ti elastocaloric parts manufactured via powder bed fusion

This study investigates the greater coefficient of Performance (COP) exhibited by the Ni-Ti lattice geometry (LS) over the solid geometry (SS) for solid-state heating and cooling. The LS's advantageous COP can be attributed to factors including variations in phase transformation behavior, a larger surface area facilitating enhanced heat transfer, and a greater volume of water heated per cycle owing to the cavities. Moreover, the LS demands lower compression forces due to its lower mass and geometry, which contribute to its heightened energy efficiency. Remarkably, the LS achieved a maximum temperature span of 11.2°C at 40 kN compression force, whereas the SS required 80 kN to attain a similar 12.9 °C span. Both the SS and LS showcased a non-linear correlation with compression force which was attributed to Lauder's transformation and pseudo-elastic behaviors. Additionally, the temperature span of the SS exhibited symmetrical behavior during heating-cooling cycles. Conversely, the LS displayed asymmetry, with a more substantial temperature change during the cooling phase than the heating phase.

Proposal of coefficients for performance analysis of reservoirs for rainwater storage

In Brazil, the existing regional disparity in water availability makes it essential to search for alternative solutions that guarantee the supply complies with water quality parameters, affordable cost and adaptation to local conditions and needs. Rainwater may satisfy these requirements. The existence, however, of numerous methods for sizing the reservoir of the system adds some subjectivity to the calculation of the storage volume and can lead to the determination of a storage value that does not meet the project's needs. In this context, this work aims to propose two coefficients, the Volumetric Idleness Coefficient (VIC) and the Volumetric Overflow Coefficient (VOC), which can be used as criteria for determining optimal volumes of reservoirs for rainwater storage. To this end, we considered three reservoir sizing methodologies, already existing in the literature, in different scenarios of catchment area and demand, with data from daily rainfall series of 37 years throughout the Brazilian territory. Additionally, an algorithm in Python was developed to obtain the values of these coefficients for the selected reservoir sizing methods for any point in Brazil, considering different scenarios of catchment area and demand. Results showed that the rainfall characteristics influence the values obtained for VIC and VOC, especially when the reservoirs are sized by a method that considers a water balance. Furthermore, an increase in demand in the catchment area causes a decrease in the values of both coefficients. Both coefficients presented in this article can be applied as reservoir sizing criteria through the comparative analysis between different sizing methods within a scenario since the method that allows a minimum coefficient is associated with an optimal reservoir volume, either for the project that aims to maximize the use of the useful storage volume (VIC) or maximize the use of the volume of water captured by the system (VOC).

Primer set evaluation and sampling method assessment for the monitoring of fish communities in the North‐western part of the Mediterranean Sea through eDNA metabarcoding

AbstractEnvironmental DNA (eDNA) metabarcoding appears to be a promising tool to survey fish communities. However, the effectiveness of this method relies on primer set performance and on a robust sampling strategy. While some studies have evaluated the efficiency of several primers for fish detection, it has not yet been assessed in situ for the Mediterranean Sea. In addition, mainly surface waters were sampled and no filter porosity testing was performed. In this pilot study, our aim was to evaluate the ability of six primer sets, targeting 12S rRNA (AcMDB07; MiFish; Tele04) or 16S rRNA (Fish16S; Fish16SFD; Vert16S) loci, to detect fish species in the Mediterranean Sea using a metabarcoding approach. We also assessed the influence of sampling depth and filter pore size (0.45 μm versus 5 μm filters). To achieve this, we developed a novel sampling strategy allowing simultaneous surface and bottom on‐site filtration of large water volumes along the same transect. We found that 16S rRNA primer sets enabled more fish taxa to be detected across each taxonomic level. The best combination was Fish16S/Vert16S/AcMDB07, which recovered 95% of the 97 fish species detected in our study. There were highly significant differences in species composition between surface and bottom samples. Filters of 0.45 μm led to the detection of significantly more fish species. Therefore, to maximize fish detection in the studied area, we recommend to filter both surface and bottom waters through 0.45 μm filters and to use a combination of these three primer sets.

Experimental investigation of storm sewer geyser using a large-scale setup

The storm sewer geyser is a process where an air–water mixture violently erupts from a manhole. Despite the low hydrostatic pressure, violent eruptions can achieve a height of tens of meters above the ground. This current study experimentally investigates large-scale violent geysers using a large air pocket inserted from a pressurized air tank. The total length of the pipe system is approximately 88 m with a 0.1572 m diameter pipe. This large-scale experiment facilitates the investigation of spontaneous geyser eruptions. This study identifies the role of air–water volume ratio and coefficient of pressure (ratio of absolute initial static pressure to initial dynamic pressure) on the geyser intensity using eruption images and pressure plots. A total of 116 cases are tested, in which the volume ratio is parametrically increased from 0 to 1.1 under various operating conditions. A geyser score is defined to quantify the geyser eruption nature based on visual observations. The key findings are as follows: first, a sharp transition in geyser intensity is observed at the critical volume ratio of 0.5, and pre-transition and post-transition intensity exhibit a linear relationship with the volume ratio; and second, the critical volume ratio linearly varies with the coefficient of pressure.