Salinity Research Articles

Hourly to weekly variations in halite precipitation from the hypersaline Dead Sea: The role of evaporation, water cooling and freshwater plume stability

ABSTRACTThick‐bedded halite sequences in the geological record are characterized by lateral variations, reflecting spatiotemporal variations in environmental forcing. Although temporal variations have been examined over seasonal scales or longer durations, there is a paucity of information regarding the dynamics of halite deposition at shorter durations of days and hours. Additionally, the influence of water discharges and surface salinity gradients remains poorly understood. Here, for the first time, in situ, hourly to weekly halite accumulation rates were measured on the Dead Sea floor (ca 20 m water depth), the only modern deep and hypersaline water body. Novel underwater photography methods were developed to directly observe halite precipitation at the lake floor, coeval with monitoring of the environmental drives, i.e. evaporation, meteorological and limnological conditions. Two fundamental environments were explored: a diluted plume environment arising from spring discharge; and a mixed hypersaline environment. The focus was on deposition during winter when the halite accumulation rate is highest, and the relationship between evaporation and halite accumulation is most straightforward since the water column is vertically uniform. Significant spatial variations in halite accumulation were found between the two environments, along with hourly variations in each environment. In the mixed hypersaline environment, over intra‐diurnal timescales, evaporation plays a more significant role in halite precipitation, whereas temperature has a greater impact on seasonal changes. In the diluted plume environment, the stability of the buoyant plume controls the rate of halite deposition; during windstorms, the plume is stirred, with higher surface water salinity and higher rate of halite accumulation. However, under calm winds, the plume is stable, with diluted surface water, and the rate of halite accumulation is a few times lower. Following these new findings, the implications for the interpretation of halite deposits are discussed.

Hybrid EOR Performance Optimization through Flue Gas–Water Alternating Gas (WAG) Injection: Investigating the Synergistic Effects of Water Salinity and Flue Gas Incorporation

Hybrid EOR Performance Optimization through Flue Gas–Water Alternating Gas (WAG) Injection: Investigating the Synergistic Effects of Water Salinity and Flue Gas Incorporation

Compilation of Consolidation Properties Data of Champlain Sea Clay from Ottawa Region

Estimation of consolidation settlements in fine-grained soils due to various civil infrastructure loads is traditionally based on results derived from consolidation tests performed on undisturbed soil samples, combined with the data of other soil properties. In many geotechnical engineering applications, consolidation settlements are also estimated using empirical consolidation parameters derived from basic soil properties. This approach relies on correlations from the literature to bypass the time-consuming and expensive sampling techniques, laboratory testing, and other associated expenses. However, these correlations may not provide reasonable consolidation settlement estimations as these correlations are typically developed without considering the influence of stress history, geology, salinity of pore water, gradation, soil fabric, and chemical properties of the soils. This is especially true for Champlain Sea clay deposits from Eastern Ontario region of Canada that are typically with heterogeneous site conditions and exhibit spatial variability of soil properties. In this paper, data from the published literature and industrial and government reports on sensitive Champlain Sea clays were gathered for the Ottawa region. The data collection and clean-up methodology towards enhancing the reliability of the gathered data is comprehensively discussed. The summarized data from this study can be used with a greater degree of confidence towards developing reliable correlations in the estimation of consolidation settlements in geotechnical engineering practice.

Mapping the Future: Revealing Habitat Preferences and Patterns of the Endangered Chilean Dolphin in Seno Skyring, Patagonia.

Species distribution modeling helps understand how environmental factors influence species distribution, creating profiles to predict presence in unexplored areas and assess ecological impacts. This study examined the habitat use and population ecology of the Chilean dolphin in Seno Skyring, Chilean Patagonia. We used three models-random forest (RF), generalized linear model (GLM), and artificial neural network (ANN)-to predict dolphin distribution based on environmental and biotic data like water temperature, salinity, and fish farm density. Our research has determined that the RF model is the most precise tool for predicting the habitat preferences of Chilean dolphins. The results indicate that these dolphins are primarily located within six kilometers of the coast, strongly correlating with areas featuring numerous fish farms, sheltered waters close to the shore with river inputs, and shallow productive zones. This suggests a potential association between dolphin presence and fish-farming activities. These findings can guide targeted conservation measures, such as regulating fish-farming practices and protecting vital coastal areas to improve the survival prospects of the Chilean dolphin. Given the extensive fish-farming industry in Chile, this research highlights the need for greater knowledge and comprehensive conservation efforts to ensure the species' long-term survival. By understanding and mitigating the impacts of fish farming and other human activities, we can better protect the habitat and well-being of Chilean dolphins.

The sedimentary environment and main controlling factors of organic matter enrichment of Carboniferous-Permian marine-continental transitional shale in Kaiping syncline

The shale from the Carboniferous and Permian Taiyuan–Shanxi Formation in Kaiping syncline has good prospects for shale gas exploration and development. To understand the evolutionary characteristics of the sedimentary environment in this area and their relationships with organic matter enrichment. Shale samples from the Taiyuan-Shanxi in Well KP1 were selected as research objects, followed by organic geochemical research, elemental geochemical analysis, and numerical analysis. The results show that the sedimentary period of the Shanxi Formation was marked by a medium productivity level. The sedimentary water column was composed of brackish water and seawater deposits in an anoxic reduction environment. The Taiyuan Formation shale was characterized by a medium level of paleoproductivity. The sedimentary water column was composed of brackish water deposits in an anoxic reduction environment. According to the linear correlation analysis of paleoenvironmental conditions and TOC content. This study suggests that ancient water salinity is the main factor controlling the enrichment of organic matter in the sedimentary stage of the Taiyuan-Shanxi Formation.

Effect of pH, Temperature, and Salinity Levels on Heavy Metal Fraction in Lake Sediments.

Heavy metals (HMs) in aquatic environments are characterized by high toxicity, a propensity for bioaccumulation, and non-degradability, and pose significant risks to biological communities. Previous studies of HMs in lakes have shown that the physical and chemical characteristics of the lake water may control both the migration of HMs in the sediments and the concentration of heavy metals in the lake water. In fact, the change in aquatic environments changes the heavy metal fraction in the sediment, which controls the release of HMs. In this paper, we investigated the effects of the pH, temperature, and salinity levels of overlying water on the chemical fraction of Cu and Zn in Wuliangsuhai Lake surface sediments. The results show that lower water pH and higher water salinity and temperature could increase Cu and Zn release from the sediment. An increase in pH led to changes in the speciation of solid fractions of Zn, namely increases in the residual fraction and decreases in the organic matter and sulfide, whereas acid-extractable and Fe-Mn oxide fractions remained largely the same. Increases in temperature and salinity led to opposite changes in the speciation of solid fractions, namely decreases in the residual fraction and increases in the organic matter and sulfide and Fe-Mn oxide fractions, whereas acid-extractable fractions remained largely the same. The effect of pH, temperature, and salinity on Cu fractions in the solids was much smaller. According to the ratio of the secondary phase to the primary phase (RSP), acidic, high-temperature, and high-salt conditions increase the release risks of Zn. Changes in water temperature have the greatest influence on the risk of Zn and Cu release from sediments, followed by the influence of salinity changes.

Effects of sodium nitroprusside foliar application on the growth characteristics and nutrient elements in some grapevine cultivars and rootstocks under salt stress conditions

Grape is a staple crop in many parts of Iran which has shown moderate sensitivity to salinity stress. Water and soil salinity is one of the major environmental stresses that strongly affect the production of agricultural products, including grapes. To overcome the harmful effects of salinity, different methods and materials are used, one of which is the use of nitric oxide. In order to explore the impact of nitric oxide on the mitigation of the negative effects of salinity stress on four grape cultivars and rootstocks (‘Bidaneh Sefid’ (Sultana) and ‘Yaghouti’ cultivars, and 140Ru and 1103 P rootstocks), a pot experiment was performed in a factorial based on a randomized complete block design with three replications. Plants were subjected to three sodium chloride (NaCl) levels of 0 (control), 25, and 50 mM and three levels of sodium nitroprusside (SNP) of 0 (control), 0.5, and 1 mM. Results indicated that increasing SNP concentration caused an increase in growth indices such as leaf area, shoot and root length, fresh and dry weights of leaves, shoots, and roots, and leaf relative water content (RWC). Furthermore, salinity decreased the concentrations of potassium (K+), calcium (Ca2+), magnesium (Mg2+), and iron (Fe2+) in leaves, while increased the amount of sodium (Na+) and chlorine (Clˉ) as well as the electrolyte leakage (EL). In addition, SNP at 0.5 and 1 mM could increase the growth efficiency and RWC as well as the elements such as K+ and Mg2+ while decreased the absorption of Na+ and Clˉ as well as the EL in plants under salinity. According to the obtained results, SNP at both concentrations (0.5 and 1 mM) had a pronounced effect on reducing the negative effect of salinity in the evaluated grape rootstocks and cultivars. In general, the positive effects of SNP on ‘Yaghouti’ and ‘Bidaneh Sefid’ cultivars were higher than those on 140Ru and 1103 P rootstocks.

Impact of Water and Soil Salinity on Coastal Agriculture in Bangladesh: Insights and Mitigation Strategies

Salinity intrusion is one of the major problems in coastal regions in Bangladesh which affects crop production and livelihood. This study examines the impact of salinity intrusion from the Pasur River on soil quality and agricultural productivity in the coastal region of Bangladesh. For this study, both water and soil collections and field surveys were carried out in seven unions that are directly impacted by the river in Dacope and Mongla Upazilas. Physicochemical analyses of water and soil samples revealed significant variations in salinity levels, with higher concentrations observed in southern regions’ spatial distribution. A strong positive relationship between water and soil salinity indicates a direct influence of river salinity on soil quality from the Pearson correlation analysis. Survey data from 240 respondents, predominantly farmers, corroborated these results, with widespread recognition of salinity’s detrimental effects on crop yields, especially rice. So, smaller farms focus on vegetables, medium on rice, and larger ones on high-value crops like watermelon. Mitigation strategies such as freshwater irrigation, drainage systems, and salt-tolerant crop cultivation were identified as potential remedies. Additionally, experts suggested implementing sluice gates to control saltwater intrusion from tributary rivers like Chila Khal. These results emphasize the immediate requirement for proactive actions to reduce the negative effects of salt-induced soil degradation and ensure sustainable agricultural practices in the vulnerable region.

The local phytoplankton community in Shizugawa Bay, Japan, from 2021 to 2022: analysis by DNA metabarcoding

ABSTRACT This study was conducted in Shizugawa Bay, located on the north-eastern coast of Japan, to determine phytoplankton assemblages. Metabarcoding with the PsbA gene and environmental surveys were conducted from May 2021 to January 2022. PCA results showed that phytoplankton assemblages changed with the environmental parameters, such as water temperature and salinity, indicating a clear seasonal pattern. The relative abundance was dominated by Chlorophyta (annual mean 34.9%) > Bacillariophyta (29.1%) > Haptophyta (17.8%) > Dinophyceae (11.7%). It is suggested that many species of Chlorophyta remain without being filtered by shellfish because the dominant representatives were pico-prasinophytes, which are of small size and are difficult for shellfish to capture. Bacillariophytes are thought to have been consumed preferentially since they are known to be a good food source for adult shellfish. Among Dinophyceae, Dinophysis spp. (causing diarrheal poisoning) were dominant throughout the period, while Alexandrium spp. (causing paralytic poisoning) showed relatively low abundance. Phaeocystis spp. (including some toxic species) were the dominant haptophytes. Cyanobacteria tended to appear particularly in summer although their mean relative abundance was less than 3%. Although the data are limited, they provide a useful snapshot of phytoplankton assemblages in Shizugawa Bay and the environmental factors that affect them.

Okra cultivation under irrigation with saline water and foliar application of hydrogen peroxide

Foliar application of hydrogen peroxide can induce plant defense mechanisms against salt stress, favoring plant acclimation in regions with qualitative and quantitative scarcity of water resources, such as the Brazilian semi-arid region. From this perspective, this study aimed to evaluate the effects of foliar hydrogen peroxide application on chlorophyll a fluorescence, growth, and production of okra under irrigation with saline water. The experiment was conducted under field conditions in Pombal, PB, using a randomized block design with a 5 × 3 factorial arrangement corresponding to five electrical conductivity levels of water – ECw (0.3, 1.3, 2.3, 3.3, and 4.3 dS m-1) and three hydrogen peroxide concentrations – H2O2 (0, 25, and 50 μM), with five replications. Irrigation water salinity levels up to 2.2 dS m-1 increase the maximum fluorescence of okra plants 75 days after transplanting. Foliar application of 50 µM hydrogen peroxide proved to be beneficial for plant height, stem diameter, stem dry matter, root dry matter, and total dry matter of okra when plants were grown in low-salinity water. The hydrogen peroxide concentrations of 25 and 50 µM increased the number of leaves. However, these concentrations reduced the average weight of the okra dry fruits. Foliar application with 50 µM hydrogen peroxide had a significant effect on the dry leaf phytomass of the okra cv. Clemson American 80 regardless of the electrical conductivity of irrigation water. Foliar hydrogen peroxide application at concentrations up to 50 µM intensifies the deleterious effects of salt stress on the total weight of dried okra fruits. Keywords: Abelmoschus esculentus L., acclimation, salt stress.

Crop Factor of Maize (Zea mays L.) and Its Relationship to the Salinity of Irrigation Water

Crop Factor of Maize (Zea mays L.) and Its Relationship to the Salinity of Irrigation Water

Effect of Seed Priming with Methyl Jasmonate and Salinity of Irrigation Water on the Emergence and Activity of Sunflower Seedlings

Effect of Seed Priming with Methyl Jasmonate and Salinity of Irrigation Water on the Emergence and Activity of Sunflower Seedlings

Effect of Irrigation Water Salinity Concentrations and Methyl jasmonate on Vegetative and Laboratory Growth Characteristics of Sunflower Crop

Effect of Irrigation Water Salinity Concentrations and Methyl jasmonate on Vegetative and Laboratory Growth Characteristics of Sunflower Crop

The Ability of the Red Tilapia (Oreochromis sp.) to Tolerate Different Concentrations of Unionized Ammonia and Water Salinity Levels

The Ability of the Red Tilapia (Oreochromis sp.) to Tolerate Different Concentrations of Unionized Ammonia and Water Salinity Levels

Analyzing the potential for Padina gymnospora cultivation in the coastal waters of St. Martin’s Island, Bay of Bengal, Bangladesh: Determining the fluctuations of physicochemical property across seasons and locations

Cultivating seaweed presents an opportunity to enhance the livelihoods of the inhabitants of St. Martin's Island inhabitants. This research investigates the suitability of the island's coastal waters for seaweed cultivation, taking into account variations in physicochemical factors in different seasons. The water temperature and salinity at various locations ranged from 24.22ºC to 27.64ºC and 23.8 to 33.76 psu, respectively. pH remained relatively constant throughout the year, fluctuating between 7.71 and 8.22. Dissolved oxygen levels were highest during the dry, cooler winter season (6.47±0.21 ppm) and lowest during the monsoon season (4.96±0.09 ppm). Electrical conductivity (EC) ranged from 39.00 mS/cm to 53.46 mS/cm, while total dissolved solids (TDS) varied between 20.35 and 27.90 g/l. Water clarity was at its peak during the dry, cooler winter season, averaging 4.14 meters. This investigation confirms the feasibility of year-round seaweed cultivation in the coastal waters around St. Martin's Island. In our study comparing cultivation methods for Padina gymnospora during the dry, cool winter season, the long-line approach resulted in a higher daily weight gain compared to the floating net method. This trend extended to growth rates by length, with the long-line method demonstrating a 5.09% daily growth and the floating net method showing 4.46%. However, net biomass production was 289.32 g/m² for the long-line method and 381.28 g/m² for the floating net method. Furthermore, the Cost-Benefit Ratio values for the long-line and floating net methods were 2.57 and 3.27, respectively. These findings affirm the viability of cultivating Padina gymnospora in coastal waters using the floating net method. Biodivers. Conserv. Bioresour. Manag. 2024, 10(1): 1-14

Changes of oxygen consumption rates in response to various environmental factors and different anesthetic methods in juvenile hybrid sturgeon, Acipenser baeri♀×Acipenser schrencki♂

Live fish transportation plays a crucial role in realizing the value of aquaculture in sturgeons. However, hypoxia and hypercapnia are the major issues during the high-density transportation of live fish. Therefore, monitoring the changing environmental factors (such as water temperature, salinity, and pH) or anesthesia methods (MS-222, dissolved CO2, or low-voltage direct electrical current), which can potentially alter the oxygen consumption of fish, are crucial for a better understanding of the necessary conditions for live fish transportation. A semi-open respirometry system was used to quantify the oxygen consumption and respiration frequency of hybrid sturgeon (Acipenser baeri♀×Acipenser schrencki♂). The results indicate that the oxygen consumption rate and respiration frequency of hybrid sturgeon increased linearly with water temperature from 1.4 °C to 25°C. The oxygen consumption rate of hybrid sturgeon increased with the increase of salinity in the range from 3 to 10 ‰ in 9 hours (P < 0.05). Respiration frequency decreased but did not affect the oxygen consumption rate when pH was from 8.1 to 9.8. Exposure to low-voltage direct electrical current ranging from 0.4 to 1.0 V/cm significantly increased the respiration frequency (P < 0.05). The oxygen consumption rate maintained below 1 mg/(g·h) when CO2 concentration ranges from 8.5 to 67.85 mg/L. Compared with the change of oxygen consumption rate and respiration frequency with MS-222 at the range from 5 to 30 mg/L, immersion of fish into more than 8.5–67.85 mg/L dissolved CO2 in water could as an alternative anesthetic method for hybrid sturgeon. These findings in the study may contribute to the culture, live fish transportation, and basic research in hybrid sturgeon.

Effect of selected environmental factors on the growth and survivability of the larvae of the Chinese sleeper Perccottus glenii Dybowski 1877

The aim of this study was to determine the influence of the temperature (range 15 to 25°C), pH (6 to 9) and salinity of water (between 0 to 10‰) on the growth, condition and survival of larvae of the Chinese sleeper. During the 28‐day experimental rearing, the highest average body weight of 81.3 ± 16.3 mg was reached in fish from the group maintained at a water temperature 25°C, and was almost five times higher than the weight at the temperature of 15°C (15.6 ± 2.2 mg). A significantly higher body weight of Chinese sleeper larvae was also recorded in the group reared in alkaline water (pH 9), compared to those kept in acidic and neutral water. Statistically significant differences between the groups (p≤0.05) were recorded for the condition index (K) values and relative body weight (SGR) only in the experiment with different water temperatures of fish rearing. The highest number (16% of the initial stock) of abnormal larvae, associated with a lower jaw and vertebral structure deformities, was recorded in the group reared at 5‰ salinity (Z5). Simultaneously, 100% mortality of the stock was noted by the 10th day of rearing in the 10‰ salinity. The cumulative mortality of the Chinese sleeper larvae related to cannibalism Types I and II in all the experimental rearing was low, oscillating between 0.5% and 11.5% in the groups bred in water with a pH 9 and 0‰ salinity, respectively. The study results may help determine the critical values of water parameters that promote or limit development in the early stages of the Chinese sleeper and could be used in activities related to eradicating or significantly reducing the increasing abundance of this alien invasive fish species in freshwater ecosystems.

Acute warming tolerance (CTmax) in zebrafish (Danio rerio) appears unaffected by changes in water salinity.

Tolerance against acute warming is an essential trait that can determine how organisms cope during heat waves, yet the mechanisms underlying it remain elusive. Water salinity has previously been suggested to modulate warming tolerance in fish and may therefore provide clues towards these limiting mechanisms. Here, using the critical thermal maximum (CTmax) test, we investigated whether short (2 hours) and long (10 days) term exposure to different water salinities (2 hours: 0-5 ppt, 10 days: 0-3 ppt) affected acute warming tolerance in zebrafish (N=263). We found that water salinity did not affect the warming tolerance of zebrafish at either time point, indicating that salinity does not affect the mechanism limiting acute warming tolerance in zebrafish at these salinity ranges, and that natural fluctuations in salinity levels might not have a large impact on acute warming tolerance in wild zebrafish.

At Shores of a Vanishing Sea: Microbial Communities of Aral and Southern Aral Sea Region

Since the early 60s of the 20th century, as a result of agricultural development in the irrigated areas of Uzbekistan, the area of the Aral Sea has decreased by 90%, while the water salinity has increased from 1% to 20%. The aim of our work was to investigate the diversity of microbial communities of water and sediments of the Western Aral Sea, as well as of the adjacent soils and reservoirs using high-throughput sequencing of the 16S rRNA genes variable V4 region. It was found that the Aral Sea water with a salinity of 22% was dominated by uncultured Archaea of the family Haloferacaceae (22‒43%), as well as by bacteria of the genera Spiribacter and Psychroflexus. In the Aral Sea sediments the share of archaea was much lower (2‒17%), and among them the uncultured Woesearchaeales predominated. Among bacteria, dominating in Aral sediments, there were sulfate reducers of the phylum ‘Desulfobacterota’, as well as representatives of the genera Fusibacter, Halanaerobium, Guyparkeria, Marinobacter, Idiomarina and Thiomicrospira. In soil samples of the former Aral Sea bed with salinity of 8.2%, a variety of archaea of the phylum Halobacterota were present, as well as uncultured bacteria of the family Nitrosococcaceae. However, in the rhizosphere of Ewresmann’s teresken plant (Kraschennininikovia ewresmanniana) growing there, archaea accounted for only 4% and mainly represented the family Nitrososphearaceae. 33% of all prokaryotes in the rhizosphere microbiome were the uncultured representatives of the phylum Actinomycetota. The microbial community of the teresken rhizosphere turned out to be similar to the microbial communities of the soil of the Ustyurt plateau, located in 3 km from the Aral Sea shore. The fresh water flowing along the former Aral Sea bed from an artificially drilled well also causes significant changes in the microbial communities: cyanobacterial mats and associated organotrophic bacteria develop along the stream bed with the increasing salinity (0.5‒2%). Finally, the greatest diversity of prokaryotes was found in the microbial community of Sudochie Lake sediment with salinity of 1%, which is probably a modern analogue of the Aral Sea microbiome before its shallowing.

Cross-Sectional Analysis of Water Access and Health Conditions in Salinity and Cyclone Prone Areas: A Case Study of Nishanbaria Village in Southern Bangladesh

The present study was conducted in Nishanbaria, a remote coastal village of Barguna district, Bangladesh where access to fresh water is the biggest problem due to salinity and cyclones along with poverty. The study applied several research methods (household survey, Key Informant Interviews, Focus Group Discussion, and observation) to conduct a cross-sectional analysis in order to identify the severity of the water problems and their impacts on people's health in this village. The study reveals that drinking and using saline and dirty water for a long time have direct impacts on health; 87.9% of the families had sick members during the field survey in 2022. The major health problems are skin diseases (according to 30.65 % of the respondents), gastric problems (25.39%), and waterborne diseases (19.35%). According to 90.3% of residents, the salinity of water has a direct impact on pregnancy and children's health and well-being. As the majority of the people collect drinking water from tube wells (80.43%), the number of people using tube wells goes down to only 24.4% after cyclones. Women are the main water collectors in this village; drinking water is collected by female members in 86.86% of the families, domestic water in 98.19%, and water for cleaning purposes in 93.56% of the families. Women are at risk of health problems; different types of pains (according to 49.36% of the residents), accidents (34.33%), and gender-based violence stem from carrying water from distant sources. Poverty (97.84% of the residents live below the poverty line) creates disparity among the residents in accessing proper treatments for all these health problems as well as collecting fresh water from distant sources. A comprehensive and context-based hazard and disaster management plan is required to help this disaster-prone village in improving freshwater availability, and their health and well-being. The Dhaka University Journal of Earth and Environmental Sciences, Vol. 12(2), 2023, P 15-26