Search Results (260)

Egyptian policymakers and researchers have been working to address the challenge of bridging the gap between limited water resources and the growing population’s needs for agricultural and food production. The National Great Project for Lining and Rehabilitation of All Open Canals of the Irrigation Network aims to reduce irrigation water losses through seepage, evaporation, and evapotranspiration. This study evaluated water losses from the Al Maanna canal network in the Assiut governorate, Middle Egypt, using empirical formulas and field ponding methods. The results show the Moleth–Worth formula was more compatible with field measurements, with estimated seepage losses of 2.07 and 2.20 million m³/month, respectively. Moreover, maximum evaporation and evapotranspiration losses were 0.086 and 1.133 million m³/month, respectively. Consequently, total water losses from the Al Maanna canal are estimated to be 3.42 million m³/month, accounting for 13.63% of the total discharge. After canal rehabilitation, evaporation and evapotranspiration losses significantly decreased, while seepage losses were lowered to 0.472 million m³/month, as estimated using the field ponding method. Hence, lining the Al Maanna canal network could reduce water losses by 84%, promoting lining processes that yield significant benefits such as moral, cultural, and environmental benefits. This approach outweighs implementation expenses and ensures a sustainable water supply. Full article

Sediments from three rivers in south-western Poland and their tributaries were used in a laboratory experiment on metal (Al, Cu, Ni, Cd, Zn, Fe, Mn) release. Metal migration was studied under different pH (pH 3.93, pH 7.29, pH 9.59) during 96 h. Al concentration was the highest in Bystrzyca and lowest in Strzegomka; other metal concentrations were highest in Nysa Szalona and lowest in Strzegomka. The values of pH and electrolytic conductivity increase throughout the experiment in acidic and neutral environments. Water pH decrease was observed under alkaline conditions, but conductivity reached higher values with time. The aluminum release showed an increase in values followed by a decrease. The highest aluminum amounts were released from the sediment from Nysa Szalona and the lowest from Strzegomka. The greatest aluminum migration was observed in the acidic medium. Similar observations were made for Mn and Zn: Strzegomka < Nysa Szalona < Bystrzyca. For Cu, Cd, Fe and Ni, the highest values were recorded in sediments in alkaline conditions. The amount of metals migrating from sediments to water remains at a similar level as presented by other researchers. More metals are released under acidic conditions. The most intensive migration of metals is noted at the beginning of the experiment. This experiment shows the existing trend of metals migration from the sediments to the over-bottom water, which is important from the point of view of the use of water for drinking purposes. Satisfactorily, the sediments in varied environments behave predictably enough that the quality of raw water under these conditions is not compromised, which is confirmed by environmental and health standards. The research performed concerns a specific area of southwestern Poland, for which this type of research has not been conducted. Full article

The aim of the study is to determine the scale of differentiation and variability of ice phenomena on the lakes in the south-eastern part of the Baltic Sea catchment area. The analysis was performed based on data from the period 1961–2020 from 15 lakes located in Poland (10) and Belarus (5). The characteristics of ice phenomena were characterized, i.e., the length of their occurrence and ice cover, the thickness of ice cover and the number of breaks occurring in the ice cover in the given years were characterized. The analysis of the course of ice phenomena made it possible to distinguish three regions with an increasing length of ice phenomenon occurrence from west to east. The zones were the west of the Vistula, the east of it and the eastern part of the Belarusian Lake District. In the analyzed multi-year period, a shortening of the duration of ice phenomena and ice cover, a decrease in the maximum thickness of the ice and an increasing number of breaks in ice cover were observed. These data correlate with the upward trend in air temperature. Full article

The article is devoted to the problems of water resources in Belarusian Polesie. Surface water resources analysis was carried out for the different types of runoffs. There was a significant decrease in maximum spring runoff and a decrease in the average annual runoff. A statistically significant increase in the minimum winter runoff is observed for the rivers of the Pripyat River basin. For the minimum summer–autumn runoff, there was no unambiguous trend in the runoff change. Quality of natural waters analysis included investigation of the annual concentrations of priority substances in the water of some rivers in Polesie for dissolved oxygen, phosphates, nitrogen, petroleum products, copper, zinc, etc. In general, there have been trends toward a pollution decrease in the Polesie Rivers. The possible consequences of changes in river runoff due to climate change are considered. The priority tasks of research on solving the Polesie water problems are outlined. Full article

(1) Background: The effects of density and the habitat conditions on the prey vulnerability in the Intraguild Predation (IGP) system were evaluated using the water bug D. rusticus as the top predator. (2) Methods: Using two different density levels (low or high) of the dipteran prey (mosquito and chironomid), the IGP system was set with A. bouvieri as the IG prey. (3) Results: The prey vulnerability was reduced in complex habitat conditions, irrespective of the prey and predator density levels and the prey identity. Correspondingly, the IG prey vulnerability was higher in the low shared prey density and complex habitat. The IG prey consumption by the top predator was higher with the mosquito as shared prey than chironomid as shared prey. Observations on the prey consumption indicated that the consumption of both the chironomid and the mosquito prey dwindled with the time for all combinations of the prey density and the habitat conditions. On a comparative scale, the prey clearance rates were higher for mosquitoes in contrast to the chironomid larvae as shared prey. (4) Conclusions: Apparently, a complex set of interactions involving the habitat conditions, top predator and the prey determines mosquito prey vulnerability against the water bug. Such interactions provide evidence for the coexistence of the mosquito larvae along with multiple predators in the wetland ecosystem. Full article

The paper presented the results of surface water temperature measurements from 17 lakes located in northern Poland and Belarus over the period of 50 years (1971–2020). Using the Excel computer program, Corel Quattro Pro 8, and graphic Draw 9, annual and monthly averages, extreme values, and annual and monthly trends were calculated and presented. These were supplemented by the monthly average air temperatures for 13 weather stations. The research showed that the temperature in all lakes was characterized by a positive trend at the level of 0.044 °C year⁻¹. The largest lake was characteristic for the Chervonoe Lake—0.066 °C year⁻¹—and the smallest 0.029 °C year⁻¹ for the deep Lake Hańcza. In the course of the average monthly surface water temperatures, a positive trend was also observed, ranging from 0.015 °C year⁻¹ in January to 0.069 °C year⁻¹ in May. These values correlated with the average air temperatures in the winter months (December–March) and with the winter NAO index (DJFM). Full article

The aim of the study was to evaluate the occurrence of integron-carrying coliform bacteria in the spring water of Warta river, a major river in Poland. We isolated 18 strains (12 Escherichia coli, three Pantoea sp., 2 Citrobacter freundii, and 1 Klebsiella oxytoca) harbouring class 1 and/or class 2 integrons. Class 1 integrons contained aadA1, dfrA7, dfrA17, dfrA1-aadA1, and dfrA17-aadA5 gene cassette arrays, whereas the genetic content of class 2 integrons was stable and consisted of sat2-aad1 gene cassette array. The strains carrying integrons were resistant to 4–11 antimicrobials, most frequently to sulfamethoxazole, ampicillin, piperacillin, trimethoprim, and trimethoprim/sulfamethoxazole. Full article

The North American freshwater snail Physella acuta has invaded and colonized a wide range of freshwater habitats, globally. Resembling other invasive species, P. acuta has several negative impacts on the invaded freshwater ecosystems, which calls for its regulation, preferably through biological control. The malacophagous leech Glossiphonia weberi, native to West Bengal, India, had been previously reported as a potential biocontrol agent of P. acuta. In this experiment, we observed the predation potential and prey preference of G. weberi on P. acuta in the presence of a native snail, Gyraulus convexiusculus. The results suggest that in all instances, G. weberi consumed less G. convexiusculus compared to P. acuta. In complex habitats, G. weberi showed significant prey preference to P. acuta except in the habitat characterized by the presence of pebbles. The complex habitats bear a significant (p < 0.05) negative impact only in the case of predation on P. acuta when present with conspecific but not in heterospecific prey conditions. Therefore, G. weberi qualifies as a useful biological control agent that can affect the colonization and expansion of the invasive snail P. acuta, even in the presence of alternative prey. Full article

The study of the importance of physicochemical parameters of water for algal growth and development in Jagdishpur Reservoir was carried out in the present research. Occurrence of algal species and values of water quality parameters also indicate the ecological nature and the present status of the reservoir. Water samples were collected from Jagdishpur Reservoir in Kapilvastu District (Nepal), in two seasons (wet and dry). The following physicochemical parameters of water were analyzed: temperature, pH, dissolved oxygen, alkalinity, concentration of nitrates and phosphates, free CO₂, hardness, conductivity, total dissolved solids. The values of free CO₂, hardness, phosphate, temperature, and dissolved oxygen were high in wet season while alkalinity, nitrate, conductivity and total dissolved solid were high in dry season. Altogether 81 algal species belonging to 53 genera and 6 classes were recorded. Higher number of algal species was recorded in the dry season rather than in the wet season. The highest number of species was noted among Chlorophyceae, followed by Cyanobacteria > Bacillariophyceae > Euglenophyceae > Crysophyceae and Dinophyceae. Cosmarium had the highest number of species (13) among all genera. During the wet season, Cosmarium, Calothrix and Phormidium were the genera with the highest number of species while Bulbochaete, Trachelomonas and Gomphonema were genera with the lowest number of species. During the dry season, Cymbella, Cosmarium and Rhopalodia were genera with highest number of species while Euglena, Gloeotrichia and Trachelomonas were genera with lowest number of species. Algal diversity was positively correlated with the increase of alkalinity, conductivity and TDS, while negatively correlated with free CO₂, hardness, concerntration of phosphates and nitrates, DO, pH and temperature. Shannon–Weiner diversity index value was higher during the dry season than in the wet season. Full article

The paper presents the analysis of the transformation of Lake Osieckie, the largest lake in the Holy Cross region until 2016. It is a valley lake that according to cartographic materials had undergone no changes in the shoreline since ca. 1938. The nearby activity of a sulphur mine required building three dikes on the lake, dividing it into four independent water bodies. The paper presents the analysis of their morphometric properties in comparison to those of the original lake. Although the basins of the new lakes are of natural origin, the currently existing four lakes can be described as quasi-natural. Full article

In high-performance competitive activities, there can be intense and prolonged exposure to water during swimming components of the competition. Therefore, water quality assessments with reference to standards are desirable to ensure athletes’ health. We evaluated whether the official criteria established for primary contact recreation in Brazilian freshwaters (CONAMA Directive 274/2000), and an integrated index of bathing conditions in Brazil (ICB), are consistent with the water quality standards stipulated by the International Triathlon Union (ITU). The water quality of Lake of Ingleses, an important venue for triathlon and open water swimming near Belo Horizonte, Minas Gerais, Brazil, was assessed between 2003 and 2019. Results for E. coli, cyanobacteria density, and pH were favorable for contact recreation and competitions at the lake. Of the variables considered, only turbidity, used as a proxy indicator of visual water clarity, was unsuitable during part of the monitoring period. The ICB agreed with the ITU standards for Very Good and Excellent quality classes and is recommended as a tool for screening sites considered for competitions in Brazilian freshwaters. However, the Brazilian national criteria for contact recreation only present standards for E. coli and pH, which is insufficient coverage of attributes affecting primary contact suitability of water in high-performance sports activities. Full article

The role of light pollution in aquatic ecosystems functioning has increased in recent times. In addition, the effect of such pollution has mostly been studied in coastal marine ecosystems, leaving freshwater ecosystems much less studied. In the p resent work, we investigated the effect of light pollution on the coastal zone of the ancient Lake Baikal ecosystem. Both a laboratory experiment and field research were conducted. The results of the experiment showed the presence of statistically significant differences (р = 0.009) between fish feeding on amphipods with and without daylight conditions, while there were no such differences between daylight and artificial light conditions. At the same time, video recordings revealed both a low number of specimens and a low species diversity of amphipods near to the village with a developed system of street lights, while in the village with a nearly nonexistent light system, the species diversity and a number of amphipods were much higher. One plausible explanation for such influence of light pollution on the quality and quantity of Baikal amphipod fauna might be the sum of several factors such as high water transparency and daily vertical migrations of amphipods. Full article