Characteristics Of Water Research Articles

Evaluation of the Phytoremediation Potential of Aquatic Plants and Associated Microorganisms for the Cleaning of Aquatic Ecosystems from Oil Products

Phytoremediation of oil pollution using free-floating aquatic plants is a promising method for water body cleaning. In this study, the influence of Eichhornia crassipes and Pistia stratiotes on the degradation of oil pollution was investigated. The loss of oil alkanes and the rheological characteristics of water were evaluated, and an analysis of the emerging rhizospheric microbial communities was carried out using high-throughput sequencing. The presence of E. crassipes and P. stratiotes plants in oil-contaminated tanks had no effect on the degradation of oil alkanes. However, the presence of plants promoted the development of rhizospheric bacteria capable of growing in oil-contaminated environments. Alpha diversity of microbial communities in oil-contaminated samples was higher in the presence of plants. Additionally, plants significantly reduced the water/oil interfacial tension, which facilitated the availability of hydrocarbons for biodegradation. A difference was noted in the microbiome between E. crassipes and P. stratiotes. Changes in the composition of microbial communities highlight the potential of E. crassipes and P. stratiotes as rhizospheric hosts for microorganisms in the phytoremediation of water bodies.

Paddy straw biochar amended sediment enhances pond productivity, growth and physiological profile of Penaeus vannamei cultured in inland saline nursery ponds.

The growing interest in commercial Inland saline aquaculture has taken momentum across the globe due to the available technologies for aquaculture and the abundant resources of saline groundwater. However, the critical problems in inland saline ponds are degraded soil and imbalanced or deficient nutrients. To address these issues, a 75-day experiment was conducted to explore the effects of Paddy Straw Biochar (PSB) as a sediment amendment on sediment quality, water characteristics, growth parameters, and the well-being of Penaeus vannamei reared in inland saline environments. PSB was applied to the nursery ponds at 1 ton/hectare (Treatment, T1) and 2 ton/hectare (Treatment, T2). The findings of water quality parameters showed a significant increase in K+ and Mg++ with a decrease in ammonia-N levels in biochar-applied ponds. Similarly, the addition of biochar to ponds (T2) resulted in improved sediment characteristics with enhanced water holding capacity (24.75%), increased soil organic carbon content (77.94%), pH levels (0.37 units), cation exchange capacity (43.15%), available potassium (16.3%), and lower bulk density (12.61%) compared to ponds subjected to control conditions at the end of the experiment. Over the experiment, improvements in sediment and water quality parameters followed the T2 > T1 > control trend. Growth characteristics showed a significant rise in the percentage of weight gain (12.398 ± 0.12), SGR (11.80 ± 0.01% day-1) and PER (2.39 ± 0.01) with reduced FCR (1.19 ± 0.00) in biochar-treated ponds (T2), followed by T1 and control. The digestive enzyme activity (amylase) and metabolic enzymes like hepatopancreatic alanine aminotransferase (ALT) and muscle ALT activities were significantly higher in shrimps raised in the biochar-applied ponds. On the other hand, the oxidative stress enzyme superoxide dismutase (SOD) in gills, muscles, and hepatopancreas (HP) exhibited lower values, suggesting reduced oxidative stress due to the biochar amendment of the pond sediment. Overall, the study recommends incorporating PSB at a rate of 2 t/ha into nursery pond sediment to enhance water quality, physiological status, and the growth of P. vannamei juveniles. Moreover, this approach improves soil and water characteristics in saline soils, making it an effective culture practice in degraded environments.

Environmental effects on abundance and size of harvested bivalve populations in intertidal shellfish grounds

Clams, razor clams and cockle are intertidal bivalve species collected on foot in the shellfish grounds of the Rías Altas (NW Spain). Spatio-temporal distribution of these bivalves are typically at the expenses of the environmental conditions of the region; however, the responses to the abiotic conditions are poorly understood. Using data from 6 species (Ruditapes decussatus, Venerupis corrugata, Ruditapes philippinarum, Cerastoderam edule, Donax trunculus and Solen marginatus) sampled in 51 intertidal shellfish grounds during 2007 and 2008, we characterized the influence of the environment (temperature, salinity, nutrient salts, suspended organic matter, or sediment granulometry and composition) on the distribution and size of these species through a comparative statistical analysis. Shellfish grounds were grouped according to their sediment and water characteristics revealing a land-ocean gradient and the influence of the geological imprint that separates bivalve grounds from West to East. Statistical models showed that R. decussatus, V. corrugata and R. philippinarum together with C. edule were more abundant in sites combining a strong marine influence with organic-rich finer sediments. However, each of those species also had different environmental niches mostly related to their particular sediment affinities, the proximity to the river mouth, and their physiological tolerances to temperature and salinity. D. trunculus was only found in outer exposed shellfish grounds, while S. marginatus abundance increased in muddy sediments. River distance was a sound descriptor of individual shell length and length variability with contrasting effects on the different species. Furthermore, slopes of length-weight relationships were steeper in autumn than in spring, and this allometry tended to be more positive in sites located closer to the rivers’ mouth, which had a higher organic matter C/N ratio. Overall, harvested intertidal bivalves had identifiable environmental preferences that influence their spatial distribution in abundance, body size, and allometric growth.

Changes in hydraulic and physico-water parameters of surface waters under the influence of anthropogenic activities in the Western Carpathians

To evaluate the quality of watercourses in the Western part of Carpathians from a hydro-chemical perspective, a systematic approach is required. This involves gradually excluding factors that contribute to the washing, mixing, and transportation of contaminants in the watercourse pathway. The model that considers spatial dependencies by autoregression was implemented in this study to determine the correlation between hydrodynamic and physico-chemical characteristics of waters at surface in different groups and forms of catchment use. The surface water at forested areas had the maximum average shear stress of 0.178 N∙m−2. The watercourse at sustained grassland had the maximum average Reynolds number (Re) of 23,654 and the minimum number of 0.426 at arable lands. Spatial autoregression analysis revealed space-time relations in various measurement points. When constructing the space-physical model, it is important to consider the influence of hydraulic characteristic parameters on the generation of physicochemical indicators in the flysch basin. Specifically, it may be beneficial to take into account the turbulent diffusion coefficient. The autoregression analysis demonstrated that for the ions P-PO43− and K+ in surface water on cropland and for total iron and the cation K+ ion grassland (p < 0.05), the turbulent diffusion coefficient proved to be of great importance. The study did not identify any physicochemical dependency for woodland surface waters. The findings can be utilised to create an erosion model that considers the contribution of material supply in a catchment area, specifically from weathered Carpathian flysch or surface runoff, to the alimentation of alluvial deposits.

Exploring Soil–Water Characteristic Curves in Transitional Oil Sands Tailings

Soil–water characteristics curves (SWCC) have proved useful in estimating parameters used in modeling unsaturated geotechnical properties of soils including permeability and strength. Either saturation, gravimetric, and instantaneous and initial volumetric water content designation can be used to develop SWCCs. Studies have shown that any of the designations will give good estimates for soils that do not undergo volume change with suction change whereas, for soils that undergo substantial volume change, only saturation and instantaneous volumetric water content designation obtained by incorporating shrinkage curves can give correct estimates. Transition oil sands tailings have fines content that cannot be categorized as sandy or fine materials, and research on volume change with suction change in these materials is limited. In this study, HyProps, Tempe cells, and a chilled-mirror water potential meter were used to measure suction and corresponding water contents for samples that were prepared by mixing coarse sand and Fluid Tailing by ratios that mimic transition zone tailings. Shrinkage tests were also performed to observe the extent of volume change with suction increase. Air Entry Values (AEV) estimated from SWCCs based on gravimetric water content were found to be lower than those estimated from saturation-based SWCCs due to substantial volume changes in these materials with suction increase. The use of saturation water content designation is recommended in estimating AEV for transitional oil sands tailings. This is useful information in predicting the long term unsaturated geotechnical behavior of these materials for environmental management and safety purposes.

Conversion of Rice Field Ecosystems from Conventional to Ecological Farming: Effects on Pesticide Fate, Ecotoxicity and Soil Properties.

Rice is an important staple food around the world, the cultivation as sustainable agriculture and food supply are key to achieving the Sustainable Development Goals (SDGs) of 2030. In order to analyze the sustainability of the rice paddy ecosystem, a comparative study was carried out during the rice growing season between paddies with conventional agriculture (CA) and ecological agriculture (EA), integrating analysis of physico-chemical characteristics of soil and soil pore water, pesticide residues, acute toxic effects and potential ecological risk, as well as aquatic invertebrate community structure dynamics. Our study found that total carbon and nitrogen present in soil were significantly higher in CA than in EA, while opposite results were found in soil pore water, implying the improvement on soil properties in EA. Neonicotinoid pesticides (thiamethoxam and thiacloprid) were still detected in EA, although no pesticides were applied after conversing CA to EA. Additionally, toxic effects to zebrafish embryos with a peak toxicity in summer (July, LC50 = 55.26 mg soil equivalent/L) were also found in EA, which was lower than in CA. The dynamics of the aquatic invertebrate community structure were correlated with the toxicity results, with higher diversity recorded in EA. Therefore, for the purpose of ecosystem sustainability, the long-term implementation of EA is highly recommended.

Z-Scheme Ag2S-Ag-In2O3 Heterostructure with Efficient Antibiotics Removal under Natural Sunlight.

The widespread distribution of antibiotics in natural waters is a great threat to human health. Photocatalytic degradation is an environmentally friendly technology to remediate antibiotic-polluted waters, driven by endless solar energy. Herein, a Z-scheme Ag2S-Ag-In2O3 heterostructure photocatalyst is prepared to remove antibiotics under environmental conditions. Under natural sunlight (light intensity: ∼78 mW/cm2) irradiation, the optimal Ag2S-Ag-In2O3 (10-ASAIO) exhibits considerable performance for decomposing diverse antibiotics, including norfloxacin (NOR), tetracycline hydrochloride, sulfisoxazole, ciprofloxacin, chlortetracycline hydrochloride, and ofloxacin. The NOR photodegradation rate constant of 10-ASAIO reaches 0.025 min-1, which is 12.50, 5.00, and 6.25 times higher than that of In2O3 (0.002 min-1), Ag-In2O3 (0.005 min-1), and Ag2S-In2O3 (0.004 min-1), respectively. This performance of the 10-ASAIO photocatalyst for decomposing NOR under natural sunlight exceeds most of the previously reported photocatalysts under a xenon lamp. Particularly, due to the intermittency of natural sunlight, a light-emitting diode (LED) lamp (light intensity: 5.1 mW/cm2) is also used as a light source, and 72.20% of NOR can be degraded with irradiation for 12 h. The effects of many water characteristics (water bodies, coexisting inorganic anions, pH, and humic acid) on the degradation performance of 10-ASAIO have been investigated, which exhibits stable degradation efficiency in variable aquatic environments. A 10-ASAIO catalyst-coated frosted glass sheet is fabricated to settle the problem of recovery of powder photocatalysts, and the immobilized catalyst shows outstanding activity and stability to decompose NOR. The photocatalytic mechanism and pathway of degrading NOR over 10-ASAIO have also been systemically investigated and proposed. The ecotoxicity (phytotoxicity and biotoxicity) of the 10-ASAIO photocatalyst and treated NOR solution have been tested by their toxic effects on cabbage seeds and Staphylococcus aureus (S. aureus). This work provides a feasible photocatalytic system for environmental pollutant remediation under natural sunlight or an LED lamp.

Characterization of natural and anthropogenic dissolved organic matter in the yangtze river basin using FT-ICR MS

Dissolved organic matter (DOM) is a complex mixture that plays a crucial role in global carbon cycling and climate dynamics. Understanding the chemical composition of DOM is crucial for studying its biogeochemical behavior. However, identifying individual DOM molecules is challenging. Here, using ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry and an in-house database, we developed a framework to investigate DOM characteristics in natural water. Through the developed approach, we successfully identified thousands of individual DOM molecules in the water bodies of the Yangtze River Basin. For the first time, the proportions of natural and anthropogenic organics within DOM were revealed. In total, 9006 unambiguous molecular formulas were assigned to DOM in the Yangtze River Basin. The proportions of CHNO and CHOS compounds increased from upstream to downstream regions. Moreover, 1099 DOM compounds were tentatively identified, with 85 % being endogenous organics and 15 % being exogenous organics. Notably, lipids and pharmaceuticals and personal care products were the most frequently detected endogenous and exogenous compounds. The spatial variation of the identified DOM indicated anthropogenic discharges considerably increased both the number and abundance of DOM in the downstream Yangtze River Basin. This study highlighted the importance of anthropogenic impacts on DOM in water.

Lithium enrichment in high-enthalpy geothermal system influenced by seawater, Indonesia

Lithium holds significant importance in energy storage and can be extracted from geothermal water, making it an additional resource to traditional mining. Combining lithium extraction from geothermal water with electricity generation from geothermal energy offers a compelling strategy to address future energy challenges. Situated in Southeast Sumatra, Indonesia, Way Ratai has considerable geothermal potential and is known for its hot springs. This study primarily aims to characterize lithium enrichment within the Way Ratai geothermal system. Water samples from various sources (one spring, seven hot springs, one well, and seawater) were analyzed for cations, anions, trace elements, and isotopic composition. The results show that Way Ratai is an old geothermal system with sodium-chloride water, where lithium enrichment is attributed to interactions between water and rocks, with some influence from seawater. The discrepancy between calculated and observed magnesium (Mg) concentrations suggests a pre-heating mixing process between rainwater and seawater. The reservoir rock in Way Ratai is mostly andesitic, with temperatures ranging from 182o to 227oC. This study enhances our understanding of thermal water characteristics, reservoir temperatures, and water origins in high enthalpy geothermal systems, offering valuable insights into lithium enrichment in coastal geothermal regions.

Static Characteristics of Hybrid Water-Lubricated Herringbone Groove Journal Bearing

Abstract The hydrodynamic herringbone groove journal bearing (HGJB) performs exceptionally well at high speeds but is limited by a low load-carrying capacity, largely due to the lubrication characteristics of water. To address this issue, a hybrid water-lubricated HGJB is proposed in this study. A lubrication model for the high-speed hybrid water-lubricated HGJB is developed, taking into account turbulence, thermal effects, and tilt. A comparative analysis of the static characteristics is conducted between the hybrid HGJB and both the hydrodynamic HGJB and the hybrid plain journal bearing (PJB). The results show that the proposed hybrid water-lubricated HGJB offers significantly greater load-carrying capacity than the conventional hydrodynamic HGJB, particularly during start-up or at low speeds. For example, when the bearing operates at 1,000 rpm with an eccentricity ratio of 0.5, the load-carrying capacity of the water-lubricated hybrid HGJB under a supply pressure of 1.6 MPa reaches 650 N, compared to just 261 N for the water-lubricated hydrodynamic HGJB. Additionally, the hybrid water-lubricated HGJB demonstrates a higher flow rate and lower temperature rise than the traditional hybrid PJB, thanks to the improved pumping effect of the herringbone grooves at high speeds.

The application of aquatic resistance exercises in different diseases

Aquatic exercise is an active exercise that make full use of the physical and hydrodynamic characteristics of water in a water environment to achieve a similar strength increase effect as land training, while avoiding the aggravation of joint stress and muscle microdamage caused by repetitive training. It has been widely studied in the field of sports rehabilitation and public fitness, while its form is basically presented in the form of aerobic exercise or interval training, the aquatic resistance exercises are often ignored by people. Due to the influence of the physical characteristics of water, the main form of muscle contraction of athletes performing resistance training in water is similar to isokinetic contraction, and the force used by practitioners is proportional to the resistance of water, which increases the centrifugal load of muscles and greatly reduces the risk of sports injury. In addition to the athletes, aquatic resistance exercises also have certain benefits for other clinical diseases. In this paper, the application of this training in swimming performance, rheumatoid arthritis, postmenopausal osteoporosis and knee osteoarthritis was reviewed in order to improve the clinical understanding and promote its rational application.

Niger Delta Oilfields Produced Water Characteristics and Treatment Technologies: Challenges and Solutions

The Nigerian Niger Delta oilfields have high water-to-oil ratio ranging from 50% to 95% water content, due to its secondary and tertiary production phases. Oil and gas producers could shut-in such wells, or develop cost effective approach for Produced Water, PW handling to meet reinjection or environmental permissibility. Thus, the study investigated the compositions and treatment techniques of Niger Delta oil and gas fields PW, and proffered solutions for actualizing minimal hazardous contaminants in PW. Characterization of PW from a Flow Station, an Oil processing and a Gas processing facilities showed biogeochemical homogeneity in the PW compositions with high organic and inorganic constituents, which are above injection and disposal specifications. The results of treated PW from the extant PW treatment (PWT) techniques showed that the total dissolved solids (TDS) concentration (6105.9 mg/l) from the Flow Station PW treatment facility did not meet the required specifications for injection into depleted wells or disposal into the environment (2,000.00 mg/l for inland, and 5,000.00 mg/l for nearshore). The salinity contents in the treated PW from the three PWT configurations were 2411.0 mg/l, 2218.6 mg/l, and 2165.4 mg/l, respectively, which were slightly above Nigerian Upstream Petroleum Regulatory Commission (NUPRC) specification (2000.0 mg/l) for nearshore disposal. The chemical oxygen demand (COD) concentration in the treated PW from the three PWT configurations were 153.0 mg/l, 148.1 mg/l, and 141.2 mg/l, respectively, which were above the NUPRC standard (125.0 mg/l). The oil and grease (O&G) concentration in the treated PW were 84.7 mg/l, 51.5 mg/l, and 58.0 mg/l, respectively, which also were above regulatory stipulation (30.0 mg/l) for nearshore disposal. The modular Bio-Unit + Ultra/Nanofiltration achieved more than 95% removal of both organic and inorganic constituents in the PW. Therefore, this study suggests that reconfiguring the extant PW treatment equipment with this cost-effective innovation would be the solution to PW treatment challenges in the Niger Delta oil and gas operations.

Cutting-edge approaches for judging surface water dynamics in semi-arid environments: Integrating landsat 8 OLI/TIRS and HYDROSAM model

This research addresses the critical need to assess surface water dynamics in semi-arid regions of Andhra Pradesh, India, by using advanced Spectral Indices for hydrological applications and methodologies. It aims to answer how remote sensing data from Landsat 8 OLI/TIRS can be effectively used to monitor and classify surface water bodies. The study applies indices such as Normalized Difference Water Index (NDWI), Modified Normalized Difference Water Index (MNDWI), Normalized Difference Thermal Index (NDTI), and Water Ratio Index (WRI). Additionally, the Weighted Composite Index (WCI) and Normalized Composite Index (NCI) are integrated with Principal Component Analysis (PCA) for multi-criteria decision making. The HYDROSAM model successfully classifies and maps various categories of surface water bodies, including non-water features (53.62%), urban water zones (37.89%), seasonal water bodies (4.32%), transitional zones (2.17%), permanent water bodies (1.05%), and river bodies (0.95%). The resultant map was validated using the AUC-ROC curve, achieving an AUC of 0.820, indicating a high level of accuracy. This methodology provides a nuanced understanding of water resource distribution and availability in the region. The findings demonstrate the robustness and reliability of the HYDROSAM model in accurately assessing surface water characteristics, thereby providing critical insights for informed water resource management, strategic land-use planning, and effective ecological conservation. This innovative methodology not only fosters sustainable water resource management in semi-arid regions but also sets a precedent for advancing research in similar ecosystems globally.

Hydrochemical Characteristics and Formation Mechanism of Geothermal Fluids in Zuogong County, Southeastern Tibet

Zuogong County is located in the southeast of Tibet, which is rich in hot spring geothermal resources, but its development and utilization degree are low, and the genetic mechanism of the geothermal system is not clear. Hydrogeochemical characteristics of geothermal water are of great significance in elucidating the genesis and evolution of geothermal systems, as well as the sustainable development and utilization of geothermal resources. The hydrogeochemical characteristics and genesis of the geothermal water in Zuogong County were investigated using hydrogeochemical analysis, a stable isotope (δD, δ18O) approach, and an inverse simulation model for water–rock reactions using the PHREEQC. The results indicated that the Zuogong geothermal system is a deep circulation heating type without a magmatic heat source. The chemical types present in the geothermal water from the Zuogong area are HCO3 and HCO3·SO4, and the main cations are Na+ and Ca2+. The groundwater is replenished by atmospheric precipitation and glacier meltwater. The salt content of geothermal water mainly comes from the interaction between water and surrounding rocks during the deep circulation process. The reservoir temperature of geothermal water in Zuogong is 120–176 °C before mixing with non-geothermal water and drops to 62–98 °C after mixing with 58 to 79% of non-geothermal water. According to the proposed conceptual model, geothermal water mainly produces water–rock interaction with aluminosilicate minerals in the deep formation, while in shallow areas it interacts mainly with sulfate minerals. These findings contribute to a better understanding of the geothermal system in Zuogong County, Tibet.

Characterizing Juvenile Common Snook and Tarpon Habitat to Guide Conservation and Restoration of Coastal Wetlands

To conserve or restore juvenile fish habitat, resource managers, restoration practitioners, and engineers need fine-scale information to understand what conditions they need to preserve or what specifications are needed to create new habitat. The objective of this study was to develop statistical models using a dataset of 18 coastal ponds in Southwest Florida, USA, to predict the abundance of juvenile common snook Centropomus undecimalis (hereafter snook) and presence of juvenile tarpon Megalops atlanticus, both of which are flagship species used for conservation and restoration of subtropical and tropical wetlands. Model predictors included water conditions and characteristics of vegetation, sediment, and geographic position. Modeling results indicated that juvenile snook used coastal ponds that were directly connected to tidal creeks. In contrast, juvenile tarpon were more likely to be present in coastal ponds that were separated from tidal creeks by dense mangrove forest (e.g., elevation > 0.48 m above Mean Low Water) characterized by highly organic sediment and low dissolved oxygen, to which tarpon are well adapted. Overlap between snook abundance and tarpon presence was greatest where connections between ponds and the nearest tidal creek were at a relatively low elevation (e.g., -0.12 m relative to Mean Low Water). Although these findings are most applicable to management and conservation of populations in areas along the Gulf coast of Florida (i.e., in areas of similar tidal range and coastal geomorphology), incorporating more detailed habitat surveys to better capture landscape context, geomorphology, and connectivity into fish sampling designs should be broadly applicable to estuarine fish ecology.

Soil Water Characteristics Curves (SWCC) of Residual Soils Stabilized using Emerging and Novel Bioinspired Technique

The development of unsaturated soil mechanics stemmed from the inadequacies of classical soil mechanics in addressing the partial pore spaces found in real-world soil systems. However, assessing soil parameters under partial saturation is resource-intensive. To streamline this, the Soil-Water Characteristic Curve (SWCC) theory was introduced. Widely applied across geotechnical engineering, water resources, and agriculture, SWCC predicts parameters of unsaturated soil systems. In geotechnical engineering, SWCC is vital for designing systems near the Earth's surface, like slopes, clay liners and foundations. Furthermore, most of conventional soil improvement techniques pose a lot of environmental concerns. thus, emergence of green construction materials widely known as bio mediated and bioinspired soil improvement techniques like Enzymatic induced calcite precipitation (EICP). EICP, an emerging eco-friendly as it employs use of simply chemical compound that reduces carbon footprints, bioinspired technique as it mimics natural forming process, was applied to stabilize tropical soil for SWCC determination. SWCC parameters were derived by subjecting EICP-treated soils at varying concentration of cementation solutions (0 – 1.00 M) using pressure plate method. Results revealed that saturated water content θs, retention water content θr, and air entry value Ψa increased with higher cementation solution concentration. The values of θs, θr, and Ψa improved from of 0.663, 0.23405, and 3.4832 at 0 concentration of cementation solution to 0.701, 0.22864, and 7.7086, respectively upon treatment with 1.00 M cementation solution. Finally, it has been demonstrated EICP is capable of improving the SWCC parameters of residual soil, thus the EICP technique can be exploited in stabilization of residual for construction of compacted clay liner.

Hypoxia cycle in shallow lakes during winter (ice-covered to melting period): Stable and decay, hypoxia, and recovery phases

This study investigates hypoxic processes beneath lake ice and explores the interactions between water environmental factors and dissolved oxygen (DO) during winter, aiming to systematically assess the influence of winter climate changes on lake ecosystems through environmental variables (physical, chemical, and biological characteristics of water). A complete hypoxic cycle in a high-altitude shallow lake was recorded using high-frequency monitoring technology, and based on a predetermined hypoxic threshold (DO<2 mg/L), it was divided into three phases: stable and decay phase, hypoxic phase, and recovery phase. Significant trend changes of environmental variables under different levels of DO were analyzed for each phase using the Mann-Kendall non-parametric test. On the basis of evaluating the overall trend of the time series, a GAM multi-factor optimization model integrating interactive effects was constructed to explore the response mechanism of environmental variables to hypoxic processes. The optimized model showed excellent explanatory performance with R2 values of 0.833 for the stable and decay phase and 0.932 for the recovery phase, with AIC values of 1554.72 and 721.03, respectively. The trend test combined with model analysis indicates that: (1) the decay of DO under the ice is primarily affected by the increase in EC, BGA, and EC*Temp, (2) the phytoplankton biomass in shallow lakes during winter has a definite contribution to the occurrence of oxygen deficiency, and (3) the water body experiences rapid reoxygenation after the ice layer breaks, but the DO level is restricted by the increase in temperature. This study highlights the ecosystem characteristics of shallow ice-covered lakes in cold arid regions, advancing our understanding of the response relationship between hypoxic aquatic environments under ice and environmental factors.

Effect of Prebiotic Supplementation on Probiotic Viability and Physicochemical Characteristics of Fermented Coconut Water with Bifidobacterium longum

Background: Probiotics and prebiotics are functional ingredients that provide health benefits to consumers but they are mainly incorporated in dairy products. Designing a non-dairy product in which probiotics and prebiotics would be incorporated would allow more consumers to benefit from their advantages. Objective: This study investigated the effect of supplementation of two different prebiotics, fructooligosaccharide (FOS) and inulin, on the viability of Bifidobacterium longum ATCC BAA-999 in coconut water. Methods: Two concentrations of prebiotics used were 1% and 2%. The physicochemical characteristics of fermented coconut water with B. longum for 9 h at 37oC and during refrigerated storage at 4oC for 2 weeks were analyzed. The viability of B. longum in fermented coconut water was maintained above the recommended therapeutic level (7 log CFU/mL) with or without supplementation with prebiotics. Results: Most distinct changes in colour (∆E &gt; 3) occurred in fermented coconut water compared to unfermented coconut water. An increase in the total soluble solids was also observed in fermented coconut water with the increase in the concentration of prebiotics. There were no significant changes in the clarity, pH, and concentrations of shikimic and malic acids in the fermented coconut water with or without supplementation with prebiotics over the 2 weeks of storage. Acetic acid production was observed in the fermented coconut water with the highest acetic acid production in the fermented coconut water supplemented with 1% FOS after 2 weeks of storage. Conclusion: This study demonstrated the potential use of coconut water as a medium to produce a probiotic drink.

Slamming characteristics of a rigid wedge during symmetric and asymmetric water entry

Abstract The slamming behavior of structures entering water is crucial for understanding wave loads on marine structures. To investigate the spatiotemporal evolution characteristics of vertical symmetric and asymmetric water slamming loads on wedges, a series of tests were conducted on rigid wedges with deadrises of 20° and 30°. During asymmetric water entry, the wedge was heeled by 5° and 10° along the Z-axis. The experimental results indicate that velocity loss and the pressure error is less than 5%. Furthermore, the peak pressure decreases with the effective deadrise increase. The analysis is discussed in the paper. The slamming behavior of structures entering water is crucial for understanding wave loads on marine structures. To investigate the spatiotemporal evolution characteristics of ver-tical symmetric and asymmetric water slamming loads on wedges, a series of tests were conducted on rigid wedges with deadrises of 20° and 30°. During asymmetric water entry, the wedge was heeled by 5° and 10° along the Z-axis. The experimental results indicate that velocity loss and the pressure error is less than 5%. Furthermore, the peak pressure decreases with the effective deadrise increase. Relevant quantitative analysis is discussed in the article.

B–Li differential enrichment of geothermal systems in the Da Qaidam and Gonghe–Guide Basin, northeastern Tibetan Plateau: Evidence from water chemistry and H–O–B–Li isotopes

Typical geothermal systems in the Da Qaidam (DQ) and Gonghe–Guide Basin (GGB) on the northeastern Tibetan Plateau (NETP) discharged different BLi contents. A widely accepted metallogenic model is that the salt–lake type BLi deposits in the TP are recharged by geothermal fluids with B–Li–rich, carried by rivers and enriched in the terminal salt lakes. The B–Li–rich geothermal water is the key source of mineralization in salt lakes, however, enrichment mechanism governing differential BLi contents in DQ and GGB geothermal systems remains ambiguous. This study systematically deciphers water chemistry and isotope characteristics (δD, δ18O, δ11B, δ7Li) of river waters, geothermal waters, sinters and surrounding rocks to discuss the enrichment process of BLi elements in the DQ and GGB geothermal systems. The δD and δ18O values of geothermal systems in the DQ (δD = −79.60 ∼ −82.40 ‰, δ18O = −10.97 ∼ −11.38 ‰) and GGB (δD = −64.00 ∼ −97.10 ‰, δ18O = −8.70 ∼ −13.00 ‰) are close to the GMWL and LMWL, indicating meteoric origin. The δD and high Cl− values (300–900 mg/L) of geothermal waters in the DQ and Qiabuqia, Qunaihai, Zhacangsi along Riyueshan of the GGB imply that these geothermal waters mixed by magmatic fluid and meteoric water. The hot springs in the DQ (B = 38.35–46.29 mg/L, Li = 3.11–3.72 mg/L) and GGB (B = 0.17–8.16 mg/L, Li = 0.08–10.49 mg/L) exhibit differential BLi geochemical characteristics. B and Li contents are higher in DQ hot springs and in hot springs along Riyueshan of the GGB, respectively. Comparison of the BLi contents and δ11B–δ7Li values of geothermal waters, sinters and host rocks reveals that BLi contents of geothermal waters are controlled by B–rich HP-UHP metamorphic rocks formed by metamorphism and Li–rich granites or pegmatites formed by magmatism in the Qilian Shan, respectively. Moreover, metamorphic and magmatic processes, combining with deep circulation reactivated by the thrust or strike–slip faults, create differential enrichment of BLi elements in the geothermal systems, such as DQ and GGB on the NETP. This study highlights into understanding the differential enrichment of BLi in the geothermal system on the TP. Furthermore, the resource elemental abundance of geothermal waters can be applied as an important prospecting indicator of endogenous BLi deposits.