Low Salinity Research Articles

Aerobic granulation and resource production under continuous and intermittent saline stress

Three sequential batch reactors (SBR) were operated to evaluate salt addition's impact on granulation, performance, and biopolymer production in aerobic granular sludge (AGS) systems. System R1 was fed without adding salt (control); system R2 operated with saline pulses, i.e., one cycle with salt (2.5 g NaCl/L) addition followed by another without salt; and R3 received continuous supplementation of 2.5 g NaCl/L. The results indicated that the reactors supplemented with salt presented higher concentrations of mixed liquor volatile suspended solids (MLVSS) and better settleability than R1, showing that osmotic pressure contributed to biomass growth, accelerated granulation, and improved physical characteristics. The faster granulation occurred in R2, thus proving the beneficial effects of intermittent salt addition through alternating pulses. Salt addition did not impair the simultaneous removal of carbon, nitrogen, and phosphorus. In fact, R2 showed better carbon removals. In conclusion, continuous or intermittent (pulsed) supplementation of 2.5 g NaCl/L did not lead to increased production of extracellular polymeric substances (EPS) and alginate-like exopolymers (ALE). This outcome could be attributed to the low saline concentration employed, a higher food-to-microorganism (F/M) ratio observed in R1, and possibly greater endogenous consumption of biopolymers in the famine period in R2 and R3 due to the greater solids retention time (SRT). Therefore, this study brings important results that contribute to a better understanding of the effect of salt in continuous dosing or in pulses as a selection pressure strategy to accelerate granulation, as well as the behavior of the AGS systems for saline effluents.

Migration characteristics and geohazards risk analysis of swelling clay in clayey silt hydrate sediments

The safe and long-term hydrate production in loose clayey silt sediments with high clay content is one of the research priorities, in which the fines migration is one of the key factors. The characteristics of montmorillonite swelling and dispersion make its migration behavior more challenging, which causes the evolution of reservoir seepage properties and potential geohazards risk cannot be predict. The migration behavior of montmorillonite induced by pore water was investigated, and discusses its potential impact on the geomechanical properties of the reservoir. The results show that the combined effects of montmorillonite swelling, which creates favorable conditions for blockage, and migration, which exacerbates permeability decline, make montmorillonite have a much greater effect on seepage characteristics in clayey silt sediments than illite. Higher montmorillonite content and low salinity increase the particle concentration in the pore water, which creates a source of particles for blockage. The low reynolds number indicates that the particles mainly detach from the pore wall with rolling in laminar flow and the lifting force can be neglected. As a result of this combined effect, the montmorillonite is more likely to readsorb and block the pore throat with bridging. This work will help to understand the migration behavior of montmorillonite in clayey silt formations with low permeability, which needs to be paid attention to when formulating gas production schemes and safety control strategies.

Seasonal Prevalence of Skin Lesions on Dolphins across a Natural Salinity Gradient

Bottlenose dolphins (Tursiops truncatus) inhabit waters across a broad natural salinity gradient and exhibit changes in skin condition based on the quality of their environment. Prolonged exposure to low salinities (≤10–20 ppt) degenerates the epidermal barrier and causes cutaneous lesions in dolphins, while the role of high salinity exposure (>35 ppt) in lesion development remains unknown. We assessed seasonal lesion prevalence in three free-ranging dolphin stocks inhabiting coastal Gulf of Mexico (GoM) waters of different salinities (0–30 ppt, 22–35 ppt, and 36+ ppt) using images of dolphin bodies. Lesions were documented on 44% of the dolphins photographed (n = 432), and lesion occurrence was significantly related to cold seasons and water temperatures but not salinity. Cold water temperatures may heighten dolphin susceptibility to infectious pathogens and disease and compound the effects of anthropogenic pollutants in the GoM. As dolphins are a bioindicator species of marine habitat welfare, natural studies assessing dolphin skin may reveal environmental degradation with potential impacts on marine ecosystems and human health.

Characteristics of rock fissure fillings and their relationship with the accumulation of uranium and associated elements in the Kailu Sag of the southern Songliao Basin, Northeast China

The relationship between deep fluids and the enrichment of uranium and associated elements in sedimentary basins remains unclear. Sandstone-type uranium deposits in the southern Songliao Basin exhibit abundant fault systems, and evidence of hot fluid activity is present in the ore-bearing strata, including the presence of hydrothermal minerals such as galena and sphalerite. To elucidate this relationship, we conducted detailed thin-section observations and micro-X-ray fluorescence spectroscopic analysis on the fissure fillings of mafic rocks, granite, sandstone, and mudstone in or near the ore-bearing strata. Our findings indicate that rock fissures are filled with minerals such as pyrite, quartz, ankerite, and calcite, suggesting that deep fluids have multiple sources and stages. Specifically, ankerite, rich in Fe and Mn, is closely associated with uranium mineralization, and is observed in both the fissure fillings and the ore-bearing strata. Fluids enriched in elements such as Tb and Dy likely originate from or are related to the mantle, while fluids with few other components may come from deep strata. However, U and Re contents are low in the fissure fillings, being insufficient for their mineralization. Furthermore, given the high content of carbonate minerals in the ore-bearing strata and their close association with uranium mineralization, we analyzed fluid inclusions and carbon–oxygen isotope composition of the carbonate minerals present in the rock fissures. Fluid inclusions in carbonate minerals indicate moderate to low temperatures (ranging from 145.5 to 298.5 ℃, with an average of 215.3 ℃) and low salinities (ranging from 0.18 to 7.99 wt%, with an average of 2.22 wt%). δ13CV-PDB values of carbonate minerals ranges from − 15.1 ‰ to 0.4 ‰, and δ18OV-SMOW values range from 0.5 ‰ to 14.4 ‰, suggesting a composite genesis of carbonate fluids involving magma and atmospheric precipitation. These test results on fissure fillings match roughly with those of the ore-bearing strata, indicating that deep fluids have infiltrated into the ore-bearing strata and contributed to uranium mineralization. Therefore, we propose that the U and Re enrichment in the ore-bearing strata originates from supergene fluids, whereas deep fluids may provide ore-forming materials such as ankerite, reducing fluids, and heat sources for uranium mineralization.

Assessing the suitability of desalination techniques for hydraulic barriers

Seawater intrusion is a worldwide increasing challenge, which lowers the freshwater availability by salination of fresh groundwater resources in coastal areas. The abstraction-desalination-recharge (ADR) methodology can combat seawater intrusion, whereby desalination is hereby the key factor for the overall efficiency of aquifer remediation. Which desalination technique is suitable within ADR depends on several factors and was not discussed before. We use a multi-criteria decision analysis and cost analysis to compare nanofiltration, reverse osmosis, electrodialysis, and (membrane) capacitive deionization and show for three case scenarios which desalination technique is most suitable within ADR. Overall, electrodialysis, nanofiltration, and reverse osmosis have shown the best utility value for saline groundwater salinity of 1–10 g L−1, whereby electrodialysis is more suitable for lower salinities. The lowest desalination costs are calculated for nanofiltration and reverse osmosis with 0.3–0.6 € m−3 depending on specific energy costs. Even capacitive deionisation can be a suitable alternative for low, slightly saline groundwater (1 g L−1) if the technology readiness level and a lifetime of electrodes increase and material costs decrease. These new insights provide a data analysis, costs, and decision support for desalination which are needed for the holistic approach to counteract seawater intrusion.

Physiological and transcriptomic analysis provides new insights into osmoregulation mechanism of Ruditapes philippinarum under low and high salinity stress

The Manila clam (Ruditapes philippinarum) is a commercially important marine bivalve, which inhabits the estuarine and mudflat areas. The osmoregulation is of great significance for molluscs adaptation to salinity fluctuations. In this study, we investigated the effects of low salinity (10 psu) and high salinity (40 psu) stress on survival and osmoregulation of the R. philippinarum. The results of physiological parameters showed that the ion (Na+, K+, Cl−) concentrations and Na+/K+-ATPase (NKA) activity of R. philippinarum decreased significantly under low salinity stress, but increased significantly under high salinity stress, indicating that there are differences in physiological adaptation of osmoregulation of R. philippinarum. In addition, we conducted the transcriptome analysis in the gills of R. philippinarum exposed to low (10 psu) and high (40 psu) salinity challenge for 48 h using RNA-seq technology. A total of 153 and 640 differentially expressed genes (DEGs) were identified in the low salinity (LS) group and high salinity (HS) group, respectively. The immune (IAP, TLR6, C1QL4, Ank3), ion transport (Slc34a2, SLC39A14), energy metabolism (PCK1, LDLRA, ACOX1) and DNA damage repair-related genes (Gadd45g, HSP70B2, GATA4) as well as FoxO, protein processing in endoplasmic reticulum and endocytosis pathways were involved in osmoregulation under low salinity stress of R. philippinarum. Conversely, the ion transport (SLC6A7, SLC6A9, SLC6A14, TRPM2), amino acid metabolism (GS, TauD, ABAT, ALDH4A1) and immune-related genes (MAP2K6, BIRC7A, CTSK, GVIN1), and amino acid metabolism pathways (beta-Alanine, Alanine, aspartate and glutamate, Glutathione) were involved in the process of osmoregulation under high salinity stress. The results obtained here revealed the difference of osmoregulation mechanism of R. philippinarum under low and high salinity stress through physiological and molecular levels. This study contributes to the assessment of salinity adaptation of bivalves in the context of climate change and provides useful information for marine resource conservation and aquaculture.

Critical insights into the Hormesis of antibiotic resistome in saline soil: Implications from salinity regulation

Soil is recognized as an important reservoir of antibiotic resistance genes (ARGs). However, the effect of salinity on the antibiotic resistome in saline soils remains largely misunderstood. In this study, high-throughput qPCR was used to investigate the impact of low-variable salinity levels on the occurrence, health risks, driving factors, and assembly processes of the antibiotic resistome. The results revealed 206 subtype ARGs across 10 categories, with medium-salinity soil exhibiting the highest abundance and number of ARGs. Among them, high-risk ARGs were enriched in medium-salinity soil. Further exploration showed that bacterial interaction favored the proliferation of ARGs. Meanwhile, functional genes related to reactive oxygen species production, membrane permeability, and adenosine triphosphate synthesis were upregulated by 6.9%, 2.9%, and 18.0%, respectively, at medium salinity compared to those at low salinity. With increasing salinity, the driver of ARGs in saline soils shifts from bacterial community to mobile gene elements, and energy supply contributed 28.2% to the ARGs at extreme salinity. As indicated by the neutral community model, stochastic processes shaped the assembly of ARGs communities in saline soils. This work emphasizes the importance of salinity on antibiotic resistome, and provides advanced insights into the fate and dissemination of ARGs in saline soils.

Transcriptome analysis reveals the molecular mechanisms underlying the enhancement of salt-tolerance in Melia azedarach under salinity stress

Melia azedarach demonstrates strong salt tolerance and thrives in harsh saline soil conditions, but the underlying mechanisms are poorly understood. In this study, we analyzed gene expression under low, medium, and high salinity conditions to gain a deeper understanding of adaptation mechanisms of M. azedarach under salt stress. The GO (gene ontology) analysis unveiled a prominent trend: as salt stress intensified, a greater number of differentially expressed genes (DEGs) became enriched in categories related to metabolic processes, catalytic activities, and membrane components. Through the analysis of the category GO:0009651 (response to salt stress), we identified four key candidate genes (CBL7, SAPK10, EDL3, and AKT1) that play a pivotal role in salt stress responses. Furthermore, the KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway enrichment analysis revealed that DEGs were significantly enriched in the plant hormone signaling pathways and starch and sucrose metabolism under both medium and high salt exposure in comparison to low salt conditions. Notably, genes involved in JAZ and MYC2 in the jasmonic acid (JA) metabolic pathway were markedly upregulated in response to high salt stress. This study offers valuable insights into the molecular mechanisms underlying M. azedarach salt tolerance and identifies potential candidate genes for enhancing salt tolerance in M. azedarach.

Duckling survival increased with availability of flooded wetland habitat and decreased with salinity concentrations in a brackish marsh

Abstract Waterfowl population recruitment is sensitive to duckling survival. We quantified predator types and survival rates for Anas platyrhynchos (Mallard) and Mareca strepera (Gadwall) ducklings in one of the largest brackish water marshes in western North America (Suisun Marsh, California) using 556 radio-tagged ducklings from 284 broods tracked during the 2016 to 2019 breeding seasons. Overall, 78% of ducklings died and 84% of mortalities occurred < 7 days after hatch. After hatching in upland fields, survival was greater for broods that hatched closer to flooded wetlands; broods had a ≥ 75% chance of surviving the move from the nest to water when nests were located ≤ 140 m from the nearest wetland and ≤ 50% chance of surviving when nests were located ≥ 970 m from the nearest wetland. Predation accounted for 91% of mortalities and was attributed to mammals (27.6%), birds (22.0%), snakes (4.4%), and unknown predators (46.0%). Anas platyrhynchos survival to fledging (54 days) was only 3.2% and 0.9% during 2 drier years and 11.7% and 16.7% during 2 wetter years. Mareca strepera survival to fledging was 9.4% to 11.2% among years. Daily survival rates for ducklings generally increased with the amount of flooded wetlands within 0.5 km (A. platyrhynchos) and 1.0 km (M. strepera) of the nest at hatch. Additionally, survival rates increased with duckling age and body mass at hatch for both species and decreased with hatch date for A. platyrhynchos but not M. strepera, which may be partially due to the earlier onset of A. platyrhynchos nesting. For ducklings that survived the initial move to water, survival rates were negatively correlated with salinity and this effect was more pronounced for younger ducklings. Anas platyrhynchos survival to 7 days post hatch decreased by 9.1% (wetter year) to 31.4% (drier year) when ducklings were in 12 ppt water (99th quantile of cumulative salinity concentrations experienced by ducklings) versus 0.5 ppt water. Mareca strepera survival to 7 days decreased by 7.4% when ducklings were in 12 ppt vs. 0.5 ppt water. Our results suggest that maintaining a network of low salinity wetlands within 1 km of upland nesting sites would likely improve duckling survival rates, especially during the critical 7-day period after hatch.

Matching field-based ranges in brackish water gradients with experimentally derived salinity tolerances of Conrad’s false mussel (Mytilopsis leucophaeata cochleata) and zebra mussel (Dreissena polymorpha)

The invasive alien false mussels Mytilopsis leucophaeata cochleata and Dreissena polymorpha (Dreissenidae) have established populations in the North Sea canal in the Netherlands that connects the harbours of Amsterdam with the North Sea. The favourable and unfavourable salinity ranges of both species were earlier studied in long-term outdoor mesocosm experiments. Their occurrence in salinity gradients in estuaries or canals connecting seaways to freshwater harbours provides information on their salinity tolerance under field conditions. By the combination of laboratory experiments and field data using the same source population a high predictability can be expected for establishment of the gradients facilitated by constructions. The reliability of experimentally derived salinity-tolerance limits for both dreissenid species was tested using data on their distribution in a salinity gradient of the littoral zone along the North Sea canal. The mussels used for the survival experiments in mesocosms were also collected from this canal. Favourable salinity ranges for adult survival in the mesocosms were 0.2 – 17.5 for M. leucophaeata cochleata and 0.2 – 6.0 for D. polymorpha. Unfavourable salinities were outside these ranges and led to high and fast mortality of these species. Mytilopsis leucophaeata cochleata was present over nearly the whole length of the North Sea canal with the highest densities close to the sea sluices where also the highest salinities and water temperatures were measured. Their densities in the canal decreased gradually at larger distances from the sea. Dreissena polymorpha co-exists with M. leucophaeata cochleata at the east end of the canal with low salinity due to the influence of freshwater of the river Rhine. The occurrence of D. polymorpha was restricted to a salinity below 4 and M. leucophaeata cochleata only occurred at a salinity above 1.5 (maximum value measured in the canal 9.2). Shorter salinity gradients with lower salinity ranges provided additional information on the co-existence of both species. Co-existence was observed at a salinity range of 1.5–3.3 (own data), 1.0–3.5 (Van Couwelaar and Van Dijk 1989), both in the North Sea canal, and 0.2–2.8, in the Canal through Voorne (Janssen and Janssen-Kruit 1967). These data correspond with studies of both species by Walton (1996) in the Hudson River (salinity range 0–3). Found salinity ranges in the North Sea canal for both species match with the tolerance results obtained by mesocosm experiments. A new invading dreissenid mussel Dreissena rostriformis bugensis and a mytilid Ischadium recurvum occur in the North Sea canal since 2006 and 2012, respectively. Competition between recent and earlier invaders is likely when salinity tolerances are similar. It has already been observed that D. rostriformis bugensis outcompetes D. polymorpha under freshwater conditions (Bij de Vaate et al. 2014; Matthews et al. 2014). Ischadium recurvum has the potential to colonize large parts of the canal and to be a strong competitor of M. leucophaeata cochleata (Goud et al. 2019). Since January 2022, the new ‘Zeesluis IJmuiden’ with the biggest locks in the world is in use, affecting the probability of population establishment of new introduced and invasive alien mussel species.

Effects of salinity on the growth, physiological and biochemical components of microalga Euchlorocystis marina

Euchlorocystis marina, a new marine species of the genus Euchlorocystis discovered in 2022, has the potential to improve the water quality in mariculture ponds. However, the effects of salinity on the growth, physiology, and biochemical composition of these algae are not well understood. In this study, changes in physiological and biochemical indices such as cell density, photosynthetic pigment, polysaccharide, and lipid content of E. marina under different salinity treatments were analyzed. The results showed that the highest cell density was observed at a salinity of 15‰. The lowest photosynthetic pigment content was observed at a salinity of 60‰, and the highest polysaccharide and lipid content was observed at a salinity of 60‰. These results indicated that lower salinity was more conducive to E. marina reproduction and growth. E. marina can accumulate polysaccharides and lipids in high salinity environments. This study provides new information for understanding the salinity adaptation strategies of E. marina and has practical significance for its development and utilization.

A culture-independent approach, supervised machine learning, and the characterization of the microbial community composition of coastal areas across the Bay of Bengal and the Arabian Sea

BackgroundCoastal areas are subject to various anthropogenic and natural influences. In this study, we investigated and compared the characteristics of two coastal regions, Andhra Pradesh (AP) and Goa (GA), focusing on pollution, anthropogenic activities, and recreational impacts. We explored three main factors influencing the differences between these coastlines: The Bay of Bengal’s shallower depth and lower salinity; upwelling phenomena due to the thermocline in the Arabian Sea; and high tides that can cause strong currents that transport pollutants and debris.ResultsThe microbial diversity in GA was significantly higher than that in AP, which might be attributed to differences in temperature, soil type, and vegetation cover. 16S rRNA amplicon sequencing and bioinformatics analysis indicated the presence of diverse microbial phyla, including candidate phyla radiation (CPR). Statistical analysis, random forest regression, and supervised machine learning models classification confirm the diversity of the microbiome accurately. Furthermore, we have identified 450 cultures of heterotrophic, biotechnologically important bacteria. Some strains were identified as novel taxa based on 16S rRNA gene sequencing, showing promising potential for further study.ConclusionThus, our study provides valuable insights into the microbial diversity and pollution levels of coastal areas in AP and GA. These findings contribute to a better understanding of the impact of anthropogenic activities and climate variations on biology of coastal ecosystems and biodiversity.

Groundwater Quality Status of the Parambikulam Aliyar Palar Basin, Tamil Nadu, India Using RS and GIS Techniques

The dependency of ground water is rising day by day. The ground water gets recharged mainly through rainfall. Thirty five water samples were collected from Parambikulam Aliyar Palar basin from open wells, bore wells and dug cum bore wells and analysed for chemical properties such as pH, Electrical Conductivity, cations and anions for two years duration (2020 and 2021) at three months interval (summer, winter, southwest monsoon, northeast monsoon) and analysed for the quality parameters. T Electrical conductivity values were ranged from 0.3 to 5.19 dsm-1, 0.29 to 6.80 dsm-1 0.3 to 6.84 dsm-1 and 0.64 to 4.17 dsm-1 during south west, north east, winter and summer seasons of 2020, respectively. The salt content was slightly increased during winter and summers seasons as compared to south west and north east. he samples were classified under USSL classification. Most of the samples come under medium salinity class (C2) (48.57%) followed by low salinity class (C1), high salinity class (C4) and very high salinity class (C3) with 28.57, 14.29 and 8.57 per cent respectively in all the seasons. Majority of the samples exhibit there is no permeability hazard. Salinity persists in the basin and possibility of salt accumulation in irrigation pipes observed from LSI values. Using remote sensing and GIS technique, the mapping was done for the groundwater quality of PAP basin. The variations in the ground water quality of the basin are directly positively correlated with rainfall pattern and geology of the basin. For effective utilization of saline water in the basin, management strategies were formulated and field experiments were conducted in the farmer’s holdings in the sampling area of the basin.

Regional differences in the air–sea CO2 flux between 3 and 14°S in the south-western tropical Atlantic

Context The fugacity of surface-seawater CO2 (fCO2sw) and the sea–air CO2 fluxes in the south-western tropical Atlantic (SWTA) were studied to increase the knowledge about the carbon cycle in this region. Aims This paper aims to describe the distribution of fCO2sw in SWTA. Methods The fCO2sw was measured from 2008 to 2020 by volunteer merchant ships with an onboard system that measures pCO2 while the vessels were underway. Key results Higher values occurred north of 8°S than in the region south of 8°S. The north is a strong source of CO2 for the atmosphere, with an annual mean value of 3.14 ± 0.52 mmol m−2 day−1. The south is a weaker source of CO2, with an annual average of 0.93 ± 0.90 mmol m−2 day−1. In the months of July and August, a weak sink of CO2 was observed, with a mean of −0.55 mmol m−2 day−1. Conclusions and implications The differences between these two regions are explained by the origin of the surface-water masses encountered along the ship track. The central branch of the South Equatorial Current (SEC) transports surface water, with a higher CO2 concentration and lower salinity, north of 8°S, whereas the surface waters between 8 and 14°S come from the southern branch of the SEC. The intertropical convergence zone is another physical process influencing the region north of 8°S.

Wastewater purification and recycling using plants in an arid environment for agricultural purposes: case of the Algerian Sahara

The aim of this study is to apply a water treatment technique (phyto-purification) in the Algerian Sahara, an arid region, to resolve the scarcity of irrigation, recycled wastewater and preserve Saharian ecosystems composed of sand and two species of aquatic plants: Typha latifolia and Imperata cylindrica. The choice of these plants was determined based on the natural vegetation, soil and climatic characteristics of the study area. To this end, we developed an experimental pilot composed of three tanks measuring 30 cm × 35 cm × 45 cm, arranged with a filter bed of sand and gravel. Two of these tanks are sown with the above-mentioned plants, while the third tank, serving as a control, is not. The values of the main wastewater pollution parameters, namely total nitrogen compounds, ammonium (NH4+), chemical oxygen demand (COD) and suspended solids measured at the outlet of the device, substantiate the performance of this treatment system. Indeed, the nitrogen reduction rate increased from 63% in the unplanted control filters to around 80% in the planted filters, and from 81 to 88% for NO3−. Regarding chemical oxygen demand (COD), the reduction rate exceeds 88.37% for the three tanks. The study of the analytical approach to modeling the purification kinetics reveals that the kinetics of COD and NH4+ are well correlated with the first-order model, with an explained variance varying between 68.1 and 81.6% for COD and 83.5 and 92.3% for ammonium. The Riverside diagram highlights that all treated water samples fall into the low sodium risk and high salinity risk class. Build on the Na% values; all purified waters have characteristics suitable for water use for irrigation.

Integrating low salinity water, surfactant solution, and functionalized magnetite nanoparticles with natural acidic groups for enhanced oil recovery: Interfacial tension study

In recent years, nanoparticles (NPs) have become a popular choice for improving oil recovery through enhanced oil recovery (EOR) methods. NPs can enhance oil recovery by reducing interfacial tension (IFT), altering wettability, and decreasing the mobility ratio. In this study, magnetic NPs with acidic groups (tartaric acid and malic acid), which are natural acids found in fruits such as grapes and apples, were synthesized and functionalized to reduce the IFT between oil and water. Various characterizations tests, including zeta potential (ZP), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), dynamic light scattering (DLS), field emission scanning electron microscopy (FE-SEM), and energy dispersive X-ray analysis (EDAX), were used to determine the properties of NPs. Afterwards, the IFT behaviour of crude oil and aqueous solutions, containing surfactant sodium dodecyl sulfate (SDS), two types of salts namely sodium chloride (NaCl) and sodium sulfate (Na2SO4), and functionalized magnetite NPs with tartaric acid and malic acid were investigated. Two crude oils were used in this study: light (A) and heavy (B). The results showed that increasing salt concentration decreases the IFT for crude oils down to an optimum point (20000 ppm for both salts), after which the IFT increases with increasing salt concentration. The presence of functionalized Fe3O4@Tartaric acid NPs (300 ppm) in the aqueous solutions containing salts at their optimum concentration (20000 ppm) and SDS (300 ppm) can decrease the IFT more significantly than that of Fe3O4 and Fe3O4@Malic acid for both crude oils. This is due to higher stability and higher ZP of functionalized Fe3O4@Tartaric acid NPs compared to Fe3O4@Malic. The IFT for oil A decreases from 20.8 mN/m to 2.87 mN/m for light crude oil and from 32.96 mN/m to 1.91 mN/m for heavy crude oil. The IFT for heavy crude oil was more reduced than that of light crude oil, which was due to the presence of asphaltene, resin, and other surface-active agents in heavy crude oil, which can act as a natural surfactant in oil and help reducing the IFT.

Role of Woody Biomass Ash Material in Immobilization of Cadmium, Lead and Zinc in Soil.

Nowadays, we have observed the dynamic development of bio-heating plants that use wood biomass for heating or energy purposes. The result of this process is a reduction in carbon dioxide emissions as well as in the production of biomass ash (BA). Despite the waste nature of BA, it should be carefully analyzed and assessed for various applications, including environmental ones. Due to the features attributed to BA, including its alkaline reaction, the high capacity of its sorption complex, relatively low salinity, and significant content of macro- and microelements, a hypothesis was put forward in this work undertaken about the positive role of BA as an immobilizing factor for Cd-, Pb-, and Zn-contaminated soils. This research was based on a pot experiment in which four series were considered: (1) BA; (2) BA + Cd; (3) BA + Pb; and (4) BA + Zn. BA was used at doses of 30, 60, and 90 mg pot-1, and metals at doses of 2 mg Cd, 100 mg Pb, and 300 mg Zn kg-1 of soil. The test plant was corn grown for green mass. The study took into account the influence of BA on the content of the total forms of heavy metals (Metot) and their available forms (Meav). In the soil without the addition of metals, a significant increase in the content of Cdtot and Cdav, and a decrease in the content of Zntot were observed due to the application of BA. The addition of metals against the background of the BA used resulted in a significant increase in Cdtot, Pbtot, and Zntot, as well as an increase in the available forms of Pbav but a decrease in Znav. However, there was no significant increase in the Cdav content. The obtained results may indicate the potentially immobilizing role of BA only in the case of zinc. They may constitute the basis for further, more detailed research aimed at determining the role of BA in the immobilization of various metals in soil.

A review of scale inhibitor methods during modified smart water injection

AbstractEnhancing oil recovery (EOR) through water flooding methods, including smart water injection, low salinity water injection, polymer injection, and surfactant injection has become a pivotal strategy for enhancing productivity. Despite their promising outcomes, these methods often encounter challenges such as scaling formation and deposition, impacting reservoir permeability and production rates. A comprehensive understanding of scaling formation is crucial for effective implementation of these methods. This article explores various scaling types prevalent in the field, examining key parameters (temperature, pressure, and pH) that influence scaling formation. Additionally, it presents a diverse range of inhibitors employing both chemical and mechanical methods to mitigate and prevent scaling, thus safeguarding reservoir performance. The efficiency of inhibitors is scrutinized concerning chemical composition and performance maintenance under different temperature and pressure conditions. This study serves as a valuable resource for researchers, engineers, and industry experts involved in the oil industry and reservoir management. By elucidating scaling mechanisms, delineating consequences, and offering extensive solutions, it enhances comprehension and provides a foundation for improving oil recovery strategies. The findings of this study contribute to a better understanding of scaling mechanisms, providing insights that can be applied to optimize oil recovery processes, mitigate reservoir challenges, and improve overall reservoir management strategies.

Determining relative permeability and capillary pressure from mixed-wet core floods

The main goal of this paper is a laboratory method development for determining the capillary pressure and relative permeability from coreflooding test specifically for mixed-wet rocks. Previously, the steady-state transient test (SSTT) was designed to determine both relative permeability (Kr) and capillary pressure (Pc) from a single steady-state coreflood by using the transient data of routine steady-state tests. On the contrary to the previous works, where SSTT was developed for completely hydrophobic or hydrophilic outcrop cores, this paper determines Kr and Pc for mixed-wet cores. Depending on the capillary pressure equation applied, the mathematical model for two-phase flow in mixed-wet rocks contains one or two extra constants, so some extra measurements must be taken during SSTT, to determine Pc and Kr curves. We change the experimental protocol by establishing a uniform initial saturation Swi by evaporation method. We also include bump floods at two high rates for the alternative determination of saturation and relative permeability for residual oil. A new inverse solver determines the set of model constants that employs van Genuchten's Pc formula and a vaporization procedure for initial core saturation. The number of resulting model coefficients is equal to seven and matches the dimension of the measured data array for mixed-wet cores.The developed SSTT for mixed-wet rocks is applied and validated for both high-salinity (HS) and low-salinity (LS) waterfloods. Strong agreement between laboratory steady-state, transient, and bump-flood data and those obtained by mathematical modelling – R2 is above 0.99 for steady-state data and above 0.9 for transient data - validates the proposed SSTT procedure and inverse solver for mixed-wet cores and HS and LS waterfloods. Our findings indicate that low salinity has a greater effect in expanding the range of positive capillary pressure compared to high salinity. This suggests an increase in water-wettability as the salinity decreases.

Environmental controls on the distribution of brGDGTs and brGMGTs across the Seine River basin (NW France): implications for bacterial tetraethers as a proxy for riverine runoff

Abstract. Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are bacterial lipids that have been widely used as environmental proxies in continental paleorecords. Another group of related lipids, branched glycerol monoalkyl glycerol tetraethers (brGMGTs), has recently been proposed as a potential paleotemperature proxy. Nevertheless, the sources and environmental dependencies of both brGDGTs and brGMGTs along the river–sea continuum are still poorly understood, complicating their application as paleoenvironmental proxies in some aquatic settings. In this study, the sources of brGDGTs and brGMGTs and the potential factors controlling their distributions are explored across the Seine River basin (NW France), which encompasses the freshwater-to-seawater continuum. BrGDGTs and brGMGTs were analyzed in soils, suspended particulate matter (SPM), and sediments (n=237) collected along the land–sea continuum of the Seine basin. Both types of compounds (i.e., brGDGTs and brGMGTs) are shown to be produced in situ, in freshwater and saltwater, based on their high concentrations and distinct distributions in aquatic settings (SPM and sediments) vs. soils. Redundancy analysis further shows that both salinity and nitrogen dominantly control the brGDGT distributions. Furthermore, the relative abundance of 6-methyl vs. that of 5-methyl brGDGTs (the IR6Me ratio), the total nitrogen (TN), the δ15N, and the chlorophyll a concentration co-vary in a specific geographical zone with low salinity, suggesting that 6-methyl brGDGTs are preferentially produced under low-salinity and high-productivity conditions. In contrast to brGDGTs, the brGMGT distribution appears to be primarily regulated by salinity, with a distinct influence on the individual homologues. Salinity is positively correlated with homologues H1020a and H1020b and negatively correlated with compounds H1020c and H1034b in SPM. This suggests that bacteria living in freshwater preferentially produce compounds H1020c and H1034b, whereas bacteria that primarily grow in saltwater appear to be predominantly responsible for the production of homologues H1020a and H1020b. Based on the abundance ratio of the freshwater-derived compounds (H1020c and H1034b) vs. their saltwater-derived homologues (H1020a and H1020b), a novel proxy, the Riverine IndeX (RIX), is proposed to trace riverine organic matter inputs, with high values (>0.5) indicating a higher riverine contribution. We successfully applied RIX to the Godavari River basin (India) and a paleorecord across the upper Paleocene and lower Eocene from the Arctic Coring Expedition at Lomonosov Ridge, showing its potential applicability to both modern samples and paleorecords.