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The two mangrove species Kandelia obovata and Sonneratia caseolaris were widely planted in the Red River delta. Both K. obovata and S. caseolaris forests play an important role in the economic development and environmental protection of the delta. However, chemical responses of the common mangrove forests to different ecological conditions in the delta have not yet been described. In this study, we evaluated chemical responses of K. obovata and S. caseolaris through comparisons of the content of metabolites and element ions in leaves of mangrove plants located under different ecological conditions in the Red River delta. In the low salinity area (Thuy Truong), specific leaf areas of K. obovata and S. caseolaris were much lower while the succulent index was higher compared to those in the high salinity area (Kim Trung). In Kim Trung, both species had a lower ratio of chlorophyll a/chlorophyll b. K. obvata in lower light (under the S. caseolaris canopy) had lower levels of chlorophyll b, resulting in a higher Chla/chlb ratio. There was no difference in the Mg content of leaves between two areas. An increase in Na content in leaves of mangrove plants in the higher salinity area was evident. The high K/Na ratio in leaves were eveluated for both species in high salinity areas. Our results also showed better uptake of K in leaves of S. caseolaris growing in the low salinity conditions (Thuy Truong), i.e. Thuy Truong has more favourable ecological conditions for S. caseolaris. Carotenoid contents in leaves of both species growing in the higher salinity were lower. [ABSTRACT FROM AUTHOR]

Distributions of a maritime harvestman, Psathyropus tenuipes and a riparian harvestman Paraumbogrella pumilio were investigated along the Sendai River, Tottori City, Honshu, Japan. Psathyropus tenuipes was found from the mouth of the river to the site 4 km upstream where slight salinity (0.1 PPT) was detected in the river. On the other hand, no specimens were found from the upstream sites where no salinity was detected. This indicates that the species needs at least a slight salinity for its occurrence. Paraumbogrella pumilio was found at five sites from the dry riverbed near the Shobu floodgate to a site on the right bank of Sendai River just upstream of Yachiyo Bridge. Occurrence of this species seems to be related to presence of open ground covered with lower grasses on the banks. Recently, the both species were also found from the right bank of the river mouth of Sendai River that is also a part of Tottori Sand Dunes. These are the first records of harvestmen from Tottori Sand Dunes. [ABSTRACT FROM AUTHOR]

Subsurface mooring allows researchers to measure the ocean properties such as water temperature, salinity, and velocity at several depths of the water column for a long period. Traditional subsurface mooring can release data only after recovered, which constrains the usage of the subsurface and deep layer data in the ocean and climate predictions. Recently, we developed a new real-time subsurface mooring (RTSM). Velocity profiles over upper 1 000 m depth and layered data from sensors up to 5 000 m depth can be real-time transmitted to the small surface buoy through underwater acoustic communication and then to the office through Beidou or Iridium satellite. To verify and refine their design and data transmission process, we deployed more than 30 sets of RTSMs in the western Pacific to do a 1-year continuous run during 2016–2018. The continuous running period of RTSM in a 1-year cycle can reach more than 260 days on average, and more than 95% of observed data can be successfully transmitted back to the office. Compared to the widely-used inductive coupling communication, wireless acoustic communication has been shown more applicable to the underwater sensor network with large depth intervals and long transmission distance to the surface. [ABSTRACT FROM AUTHOR]

• A salinity sensor based on fiber Bragg grating is developed. • The water diffusion model of the lamellar polyimide is presented. • After the encapsulation, the sensor can measure salinity and temperature. • The sensor possesses prospects for monitoring the process of seawater intrusion. Under the influence of climate warming, sea level rise and human activities, seawater intrusion has become a significant problem. Seawater intrusion salinates groundwater and impacts on ecological environment and society. It needs to be monitored to scale to environment in order to develop and implement preventive or remedial measures. In-situ large-scale monitoring of groundwater salinity is a key step in the prevention of seawater intrusion. However, current monitoring technologies are either too labor-intensive or excessively expensive when used in large-scale in-situ monitoring. Optical fiber techniques that are presently used in measurements of salinity are mostly limited to laboratory experiments. Herein, a fiber Bragg grating (FBG) salinity sensor for in-situ monitoring of groundwater salinity is proposed. The sensor is composed of a FBG coated with polyimide (PI) and an uncoated FBG for salinity sensing and temperature compensation. On the basis of feasibility test and analyses using water diffusion model, a mathematical matrix for calculating salinity and temperature is proposed and applied to salinity measurement in gravel aquifers. The results indicate that the sensitivity coefficients of FBG coated with lamellar polyimide, to water salinity and temperature, are −0.0358 nm/%, 0.0321 nm/°C, respectively. The uncoated FBG is only sensitive to temperature, and the sensitivity coefficient is 0.0095 nm/%. The results of gravel aquifer measurements show that the FBG salinity sensor has good repeatability and consistency with measurements obtained with an electronic salinity meter. The absolute and RMS errors of the salinity measurements are −0.16 to 0.21%, 0.1048%, respectively, and the absolute and RMS errors of temperature are −0.31 to 0.33 °C, 0.1917 °C, respectively. The FBG salinity sensor provides a new means for in-situ monitoring of seawater intrusion. [ABSTRACT FROM AUTHOR]

Abstract Hydrolyzed polyacrylamide (HPAM) has been widely used in chemically enhanced oil recovery (EOR) processes. However, the sensitivity to salinity limited the utility of HPAM polymers for many potential EOR applications in high-salinity reservoirs. To overcome the HPAM salinity sensitiviy shortcoming, the authors developed anti-salt polymers (ASPs) with high salt-tolerance to be used for mobility-control. ASP is an electrolyte-responsive terpolymer of an acrylamide (AM) with 2-acrylamido-methylpropane-sulphonic acid sodium salt (NaAMPS) and a monomer that is much like N-(4-benzoylphenyl) acrylamide (BPAm). Generally, for reservoirs that have high total dissolved solids (TDS) in water, ASP solutions are projected to generate a high-viscosity injected fluid. However, debates are ongoing as to whether ASP can be successfully applied to low-permeability reservoirs if produced water is used as the polymer mixing water. In this study, produced water taken from block 2 of the Pubei Oilfield development zone in Daqing with a TDS of 12910 mg/L was used to prepare and dilute the polymer aqueous solutions. Comparative experiments with ASPs and HPAM were conducted in regard to their viscosity, stabilities, hydrodynamic radii, and core flooding feasibilities. ASPs had better thickening ability compared with HPAM in produced water. Even with low retention rates, ASP aqueous solutions still held a favorable viscosity after aging for 15 days. Core flooding experiments demonstrated that ASPs has good propagation in porous media and acceptable behavior as a displacing fluid. Improved oil recoveries of 9.54, 13.34, and 15.64% were achieved during the injection of ASP solutions and subsequent water flooding. Furthermore, the result from the pilot test showed that ASP was successfully used in block 2 of the Pubei Oilfield development zone in Daqing, which provides a reference for other oilfields' mobility-control. Highlights • Anti-salt polymer have good thickening behavior when being mixed with produced water. • Anti-salt polymer solution shows acceptable transportation in low-permeability cores. • Anti-salt polymer can significantly improve the oil recovery. • Anti-salt polymer achieved success in pilot test in Pubei development zone in Daqing oil field. [ABSTRACT FROM AUTHOR]

Abstract Sodium chloride (halite) has been traditionally regarded as an unconventional oilfield mineral scale, compared with more prevalent carbonate and sulfate scales. However, with the increasing productions from offshore deepwater and shale gas fields, halite scale occurrence becomes more frequent, leading to significant technical and financial challenges to productions. Although low-salinity water dilution remains the primary approach in controlling halite scale threat, chemical inhibition has been evaluated as an alternative halite control strategy due to the intrinsic issues associated with low-salinity water availability and water quality. There are limited studies concerning the combined effect of metals, especially transition metals with scale inhibitors in halite control. In this study, the combined effect of a number of transition metal ions with two common halite scale inhibitors was evaluated in a laboratory setup. It was found that among the transition metals studied, Pb2+ ion demonstrates a synergistic effect with the scale inhibitors evaluated by considerably extending the halite induction time. The calculated inhibition efficiency also indicates that the presence of Pb2+ improves inhibitor performance. Although Pb2+ is an environmental pollutant, an aqueous Pb2+ concentration of up to 10 mg L−1 can naturally occur in both natural gas produced water and oilfield produced water. The operators can take advantage of the reported synergistic effect of Pb2+ with scale inhibitors in this study while designing field halite control strategy. The enhanced inhibition efficiency elaborated in this study can be useful in designing the halite scale control strategy, if a decent amount of Pb2+ is present in the produced water. Graphical abstract Image 1 Highlights • Combined effect of transition metals with halite inhibitors was evaluated. • FCN is superior than PAA with a prolonged halite induction time. • Pb2+ ion demonstrates a synergistic effect with both FCN and PAA inhibitors. • Calculated inhibition efficiency is the highest for Pb2+ with FCN inhibitor. [ABSTRACT FROM AUTHOR]

Abstract Enhanced oil recovery by low-salinity waterflooding (LSW) has been shown to result from the combined effect of various physical mechanisms. In this study, laboratory experiments were designed in such a way that only fines migration mechanism remains active. Then, experimental observations and detailed characterizations of core plugs and produced fluids (water and oil) were used to analyze the effect of fines migration-induced formation damage on displacement efficiency. In the first set of experiments, core plugs of Berea and Obernkirchener sandstones were subjected to single-phase injections of water at salinities 40, 30, 20, 10, 5, 2.5, 0.5 and 0 g/L NaCl. An order-of-magnitude decrease in permeability was observed for both core plugs and was associated with an increase in fines concentration in the produced water. SEM-EDS images of the produced fines showed that kaolinite is mobilized as the salinity is reduced. SEM images of the pores before and after injection also showed fines retention and blockage. In the second set of experiments, two-phase LSW was performed on a pair of core plugs comparable to those in the first set of experiments. Kaolinite migration results were consistent with those of single-phase LSW. The two-phase LSW experiments showed 50% reduction in water relative permeability and 3% increase in oil recovery. Because no wettability alteration mechanism was active, the increase in oil recovery is attributed solely to enhanced displacement due to fines migration. Highlights • Laboratory experiments are performed on Berea (300 mDarcy) and Obernkirchener (3 mDarcy) core samples. • SEM-EDS analysis of the produced fines show production of kaolinite and quartz fines. • Permeability damage is associated with the production of kaolinite fines. • Higher recovery is observed after low-salinity waterflooding in both high-permeability and low-permeability core samples. [ABSTRACT FROM AUTHOR]

Abstract Irrigation water salinity effects on oregano growth, water use, yield and quality parameters were investigated. For this aim, eight irrigation water salinity levels including 0.54 (control), 1.2, 1.8, 2.5, 3.5, 5.0, 7.0 and 10 dS/m were utilized. The plants in all of 7 and 10 dS/m and two out of five replications of 5 dS/m treatment could not survive until the end of the experiment. The mean soil salinity and seasonal averaged drainage water salinity values increased with increasing salinities of applied irrigation water. Compared to control 27, 33, 44 and 74% reductions in total dry yields, and 27, 38, 49, and 77% decreases in dry leaf yields were calculated for 1.8, 2.5, 3.5 and 5 dS/m treatments, respectively. In general, increased irrigation water salinity caused increases in total phenolic content, total flavonoid content, extract yield which shows the amount of water extractable matter from the plants and antioxidant activity whereas significant decreases in total oil content. Among the essential oil components, carvacrol, β-cymene and γ-terpinene contents decreased with increasing water salinities up to 2.5 dS/m and after this level sharply increased but linalool content showed a reversed pattern. A threshold value of 0.50 dS/m was calculated for total fresh yield of oregano but it was not possible to determine a threshold salinity value for total dry yield, dry leaf yield and total oil content. Based on these results, oregano is a very sensitive plant to salinity. [ABSTRACT FROM AUTHOR]

Abstract To examine how the rates and pathways of anaerobic organic carbon mineralization (AOCM) of tidal freshwater wetlands change with low-level increases in salinity, we investigated the rates and controls of microbial iron and sulfate reduction, methane production, and total AOCM in tidal wetlands along a freshwater to oligohaline (0.1–3.3 ppt) gradient in the Min River Estuary in southeastern China. Porewater chloride was found to be strongly correlated with total organic carbon (TOC), carbon to nitrogen (C:N) ratios, and porewater geochemistry (sulfate, pH, ammonium, and dissolved methane levels). Furthermore, a higher plant biomass, larger iron oxides pool, and lower sulfide levels were observed in the oligohaline wetlands. The contribution of microbial sulfate reduction to AOCM increased from 16% to 67%. In contrast, the contribution of microbial iron reduction and methane production declined from 52% to 22% and 12% to 2%, respectively, along the increasing salinity gradient. No consistent changes were found in the total AOCM rates. The rates of methane production were primarily controlled by the C:N ratios and concentrations of porewater ammonium and amorphous iron oxides, while the microbial sulfate and iron reduction rates were mainly controlled by belowground biomass, water content, and concentrations of porewater chloride and sulfate. Our findings provide insight into the potential consequences of modest saltwater intrusion; these may not alter the rates of AOCM in the Min River Estuary, but could change the dominant AOCM pathway from microbial iron reduction to sulfate reduction and accelerate sulfidic effects in this historically freshwater wetland ecosystem. Graphical abstract Unlabelled Image Highlights • The rates of total anaerobic organic matter mineralization are tolerant to a low-level increase in salinity. • The anaerobic organic matter mineralization pathway is sensitive to minor salinity changes. • Salinity are responsible for the decline in microbial iron reduction, suppression of methane production, and enhancement of sulfate reduction. [ABSTRACT FROM AUTHOR]

Highlights • Low salinity (0–2%) had negligible influence on the SNAP process. • The SNAP process could treat 3% salinity wastewater by enhanced aeration. • As low as 0.5% salinity had severe suppression on NOB activity. • The enhanced aeration could selectively stand out the AOB and anammox activities. • The AOB could produce more ammonia monooxygenase to fight against the salinity. Abstract In this study, acclimation of freshwater nitritation-anammox sludge to remove nitrogen in high saline and hypersaline wastewater was evaluated, during which the microbes activity and microbial community revolution were revealed to understand the fate of a nitritation-anammox process (SNAP) in response to increasing salt stress. By enhanced aeration, the SNAP system can treat saline (3%) ammonium-rich (185 mg/L) wastewater after gradual adaption. Hypersalinity (5%) caused final deterioration of the SNAP system due to a severe inhibition on anammox activity. Genera Kuenenia (anammox), Nitrosomonas (AOB) and Nitrosovibrio (AOB) bacteria were salt adaptable microbes, while genus Nitrospira (NOB) bacteria were sensitive to salinity. Under the enhanced aeration, AOB bacteria could bear 3% salinity with possible enriched ammonia monooxygenase to stimulate the conversion of ammonium to nitrite by producing more intermediate-hydroxylamine, which could alleviate the negative effect of insufficient hydroxylamine oxidase members in AOB bacteria. [ABSTRACT FROM AUTHOR]

Previous short-duration depuration studies with the eastern oyster (Crassostrea virginica) demonstrated difficulty in achieving significant naturally incurred Vibrio vulnificus population count reductions. The present study used long-duration depuration (14 days) at controlled temperatures (10 or 22°C) and salinities (12, 16, or 20 mg/g). All depuration temperature–salinity combinations significantly reduced V. vulnificus counts, with greatest reductions seen in 12 mg/g, 10°C seawater (2.7-log CFU/g reduction) and in 20 mg/g, 22°C seawater (2.8-log reduction). Mesophilic vibrios dominated the overall microflora of freshly harvested oysters, whereas refrigerated storage selected for psychrotrophic bacteria (Pseudomonas spp., Aeromonas spp., Shewanella spp., Psychrobacter spp.) as well as did depuration at 10°C (Pseudoalteromonas spp., Shewanella spp., Vibrio spp.). Depuration at 22°C retained dominance of mesophilic vibrios, including pathogenic species, followed by Shewanella spp., Pseudoalteromonas spp., and Photobacterium spp. Although aerobic plate counts were lower in 22°C depurated oysters (5.0 log versus 6.0 log) compared with 10°C, depuration at 10°C offered greater V. vulnificus population reductions than depuration at 22°C. This advantage was only seen at 12 mg/g salinity, with no impact at 16 and 20 mg/g salinities. No depuration treatment reduced V. vulnificus counts to nondetectable levels. Use of prolonged depuration may be a helpful intervention to control V. vulnificus populations in oysters. [ABSTRACT FROM AUTHOR]

Abstract Detailed sedimentological and ichnological analysis of core material from selected wells were performed in order to fully characterize the range of facies encountered within Cenomanian formations of Ivorian offshore basin. Results indicate that the cored successions comprise four major groups of lithofacies: Pebbly (CS, PS) , clean sandstone (S) , muddy sandstone (S*M) and mudstone (HM, ML, MJ & M). These lithofacies groups were further sub-divided into component facies based mainly on sedimentary structures. The pebbly group comprises conglomerate sandy and pebbly sandstone. The clean sandstone group includes seven facies: massive sandstone, laminated sandstone, cross-bedded sandstone, bioturbated sandstone, deformed sandstone, wavy-bedded sandstone and rippled sandstone. The muddy sandstone group comprises bioturbated muddy sandstone, while the mudstone group comprises four main facies, namely wavy-bedded heterolithic/sandy mudstone, calcareous mudstone, silty mudstone and pure mudstone. A range of ichnofossils were identified in the cores including: Planolites isp, Palaeophycus isp, Lockeia isp, Phycosiphon isp, Thalassinoides isp, Rhizocorallium isp, Cylindrichnus isp, Chondrites isp and Teichichnus isp. Among these, the Phycosiphon isp Chondrites isp and Rhizocorallium isp reveal fully marine salinities in some intervals of these cores, although Chondrites isp usually used as proxy for disoxia and Rhizocorallium isp were sometimes associated with Glossifungites isp ichnofossils. Integration of the sedimentary data (lithofacies) and trace fossil ichnofossils data revealed several depositional environments ranging from coastal/deltaic to shallow marine settings within the Cenomanian cores. Highlights • Four lithofacies: Pebbly, sandstone, muddy sandstone, mudstone. • Main sedimentary structures: structureless, lamination, ripple, cross and wavy- bedded. • Main trace fossils: Rhizocorrallium isp , Chondrites isp , Planolites isp , Thalassinoides isp , Teichichnus isp , Palaeophycus isp., Lockeia isp, Phycosiphon isp, Cylindrichnus isp. • Phycosiphon isp Chondrites isp , Rhizocorallium isp reveal fully marine salinities. • Several depositional environments ranging from coastal/deltaic to shallow marine settings. [ABSTRACT FROM AUTHOR]

Abstract The estuaries are characterized by the formation of salinity gradients and are frequently associated with anthropic activities. Studies that show the condition of organisms against the natural environmental variations are fundamental for future evaluation of environmental change due to anthropic impacts. Biomarkers are useful tools defined as biological changes in low levels of organization induced by stressors and considered as predictive responses of more severe effects. The aim of this study was to characterize the modulation of biochemical biomarkers in Ucides cordatus against the natural variation a pristine mangrove forest in an Amazonic estuary (Japerica Bay). The samplings were carried out throughout one year at rainy-dry transitional period (June/2013), dry period (September/ 2013), dry-rainy transitional period (November/ 2013) and rainy period (February/ 2014) in the lower, middle and upper estuary. The biochemical biomarkers evaluated were glutathione-S-transferase (GST), glutamate cysteine-ligase (GCL), total antioxidant capacity (ACAP), reduced glutathione (GSH) concentration and the lipid peroxidation (LPO). There was a decrease in the activity of both enzymes, GSH concentration and lower LPO in the rainy-dry transitional period for the organisms of all sites, pointing to this period as a season of greater metabolic stability. The organisms, especially those of the middle estuary, presented physiological plasticity against the variations of the environment which they are submitted. Seasonality, more than salinity influence due to position in estuary, is the main modulator of biomarkers. Also, our results indicate that the species presents high viability for biomonitoring studies. Highlights • Biochemical biomarkers in U. cordatus from a pristine mangrove forest in an Amazonic estuary was seasonally characterized. • Antioxidant defenses and the lipid peroxidation (LPO) were determined in crabs from lower, middle and upper estuary. • The organisms presented physiological plasticity against the environmental variations that they are submitted. • Seasonality is the main modulator of analyzed biomarkers. • U. cordatus presents a high viability as a sentinel species for biomonitoring studies. [ABSTRACT FROM AUTHOR]

Abstract Sufficient swelling pressure of compacted bentonite upon wetting is necessary to provide long-term stability to an engineered barrier system under conditions of thermal gradient and variable water chemistry in a high-level radioactive waste repository. To investigate the combined thermal and saline effects on the swelling pressure of Gaomiaozi (GMZ) bentonite, constant-volume swelling pressure tests were performed on densely compacted specimens inundated with deionized water, NaCl, and CaCl 2 solutions at 20 °C and 60 °C. The results indicate that high temperature and saline solutions decrease the swelling pressure. Crystalline swelling dominates the constant-volume swelling of densely compacted bentonite. For a given cation type, a higher temperature or higher solution concentration resulted in a lower swelling pressure. The decreasing surface potential and increasing osmotic suction with solution concentration both weaken the clay swelling. The effects of temperature on the swelling pressure are explained by the role of the lattice contraction. The degeneration of the interlamellar adsorbed water at high temperature weakens the crystalline swelling. The effects of cation types are interpreted by their difference in chemical activity. Ca2+ ions possess higher exchange capacity and larger hydrated radius than those of the Na+ ions. When densely compacted Na-bentonite is wetted with CaCl 2 solution, the possible change of the interlamellar cations from Na+ to Ca2+ ions would promote the crystalline swelling. The osmotic suction imposed by CaCl 2 solution may offset the role of the cation exchange to a small extent. The effect of temperature on the swelling pressure exceeds that of the cation types. For a given solution concentration, the specimen wetted with NaCl solution developed lower swelling pressure than that with CaCl 2 solution at 20 °C, whereas the opposite tendency appeared at 60 °C. In addition, specimens saturated with deionized water and NaCl solution at 20 °C obtained insignificant difference in pore size distribution, whereas identifiable differences in pore size distribution occured at 60 °C. The combined thermal and saline effects on the swelling pressure may be explained by the role of the lattice contraction at varied clay structure. When CaCl 2 solution is used, the quasicrystals contain more montmorillonite layers than the case of the NaCl solution. The role of the lattice contraction at high temperature is expected to decrease the swelling pressure to a greater degree in the case of the CaCl 2 solution. The remarkable increase in the osmotic suction at high temperature and high solution concentration could also enlarge the decrease in the swelling pressure. These conjectures, however, still require quantitative interpretations via microscopic tests such as X-ray powder diffraction tests on bulk samples. Highlights • High temperature preferentially dominates crystalline swelling. • High temperature has greater effects on PSD. [ABSTRACT FROM AUTHOR]

Abstract The framework of the intrinsic compression behaviour of normally consolidated soft clay proposed by Burland (1990) is widely adopted in engineering practices. However, further investigations should be conducted on its validity in the coastal and offshore environments to verify the effect of pore water salinity. In the present work, oedometer tests were performed on remoulded artificial soft clays (mixtures of kaolin and bentonite with 0%, 5%, 10%, and 20% of bentonite by mass). The artificial clays were salinized with sodium chloride solutions at concentrations 0 mol/L (distilled water), 0.17 mol/L, 0.51 mol/L, 0.86 mol/L, and 1.70 mol/L at water contents equal to 1.0–1.5 times of the liquid limits. The results showed that the 'intrinsic' properties of clays, including the compression index C c ⁎(100–1000 kPa), void ratio e 100 *, and compression line based on the void index I v , changed with the pore water salinity. Following the empirical correlation proposed by previous researchers, the decrease in C c ⁎ caused by pore water salinity could be generally characterised by the liquid limit and void ratio at the liquid limit (e L). The dispersed correlation between the predicted e 100 ⁎ and the experimental results in this study were caused by the significant changes in e 0 / e L controlled by pore water salinity. The relationships between void index I v and vertical stress σ v ' deviated from the intrinsic compression line (ICL) under the saline environment. For the artificial clay rich in smectite, the slopes of I v –log σ v ' before yielding increased with pore water salinity at the initial water content. Pore water salinity affected the intrinsic compression behaviour of soft clays primarily composed of kaolinite to a lesser extent. Highlights • The pore water salinity changes e 100 ⁎. • Normalised compression curve deviates from Burland's intrinsic compression line at small stress. • Burland's framework needs to be updated considering salinity effect and small stress. • The particle flocculation alters the intrinsic compression behaviour of remoulded soft clays. [ABSTRACT FROM AUTHOR]

Double diffusion convection, driven by two constituents of the fluid with different molecular diffusivity, is widely applied in oceanography and large number of other fields like astrophysics, geology, chemistry and metallurgy. In case of ocean, heat (T) and salinity (S) are the two components with varying diffusivity, where heat diffuses hundred times faster than salt. Component (T) stabilizes the system whereas components (S) destabilizes the system with overall density remains stable and forms the rising and sinking fingers known as salt fingers. Recent observations suggest that salt finger characteristics such as growth rates, wavenumber, and fluxes are strongly depending on the Rayleigh numbers as major driving force. In this paper, we corroborate this observation with the help of experiments, numerical simulations and linear theory. An eigenvalue expression for growth rate is derived from the linearized governing equations with explicit dependence on Rayleigh numbers, density stability ratio, Prandtl number and diffusivity ratio. Expressions for fastest growing fingers are also derived as a function various non-dimensional parameter. The predicted results corroborate well with the data reported from the field measurements, experiments and numerical simulations. [ABSTRACT FROM AUTHOR]

Spring water is a reliable source of potable water in many parts of the world. Uplifted coasts of the Southern Kerala host many high yielding cold water springs which emerge from the sand - clay interface of the Neogene outcrops. Lack of adequate studies on the hydrological and water quality aspects of these springs is challenging the wise use and management of these springs. Therefore, an attempt has been made to map the locations and study the water quality of the free-falling type of springs emerging from the Neogene outcrops exposed on the cliffed coasts of Southern Kerala, especially falling within the jurisdiction of Kollam and Thiruvananthapuram districts. A total of 31 springs from four distinct geomorphic settings has been located in our survey conducted in 2008-2009 period. But, our recent survey carried out in March 2017 revealed that about 10 % of the springs were dried out due to various reasons. The total spring water discharge during 2017 was about 450 liters/minute against the total discharge of 800 liters/minute in 2007-08 period. In general, the hydrochemistry of spring waters is dominated by alkali and strong acids, i.e. alkali-chloride type. Most of the hydrochemical parameters exhibit a great degree of seasonal and spatial variations and are well within the permissible limits (with the exception of pH) for all four groups of springs. The low mineral contents may be attributed to minimal weathering from silicate-rich rocks and insignificant leaching from soil due to infiltration from anthropogenic activities. The spring water quality in all the four groups of the study area is bacteriologically contaminated and therefore proper disinfection is required before human consumption. Most of the spring water samples are classified to be “excellent to good” for irrigation and is not expected to cause any salinity hazard. [ABSTRACT FROM AUTHOR]

The mineral rock salts present in the Mahai Salt Lake of the Qaidam basin exhibit high solubilities in water. In addition, the multicomponent underground brine exhibits a high salinity and is easily precipitated. In the natural state, brine transport in the brine layer is extremely slow, and the brine is in a relatively stable chemical equilibrium state with the rock salt media. However, during mining, both the seepage and the chemical fields fluctuate significantly, thereby disrupting the equilibrium and leading to variations in the chemical composition and dynamic characteristics of the brine. Therefore, we selected underground brine from the Mahai Salt Lake, collecting a total of 183 brine samples over three stages of mining (i.e., the early stage of underground brine extraction, the initial stage of mining, and the later stage of mining). Using a range of analytical techniques, the chemical dynamics of the underground brine water and its evolution were systematically studied. We found that evaporation and enrichment were the main mechanisms of underground brine evolution in the Mahai Salt Lake, with cation exchange and mineral dissolution/precipitation being key factors in determining the dynamic characteristics and evolution of the brine. [ABSTRACT FROM AUTHOR]

To better understand the factors that influence seafloor serpentinite mudflows, such as those recently documented on the Marianas seamounts, we have conducted rheological measurements on composite serpentine-brucite suspensions at 7 °C and a salt concentration of 0.6 M. The resulting flow curves were fitted by the Bingham fluid model, from which the Bingham yield stress and plastic viscosity of each suspension was determined. Both the yield stress and plastic viscosity increase as the water content of the suspension decreases. Increasing the brucite fraction in the solid mixture results in an increase in yield stress and a decrease in viscosity of the suspension for the same water/solid ratio. Physicochemical parameters such as pH, temperature and electrolyte concentration also moderately affect the rheology of the suspension, but the influence is not as significant as has been previously observed for suspensions containing smectite. The results suggest that mineral composition of the serpentinite mud, especially the abundance of brucite, has as much of an impact as water content on variable mudflow behaviors such as those observed at the Mariana seamounts. [ABSTRACT FROM AUTHOR]

Mangrove forests and adjacent creeks are known to be highly productive estuaries, which are partly supported by benthic microalgae that grow on the sediments. During surveys investigating the microalgal floras of mangrove swamps in the eastern part of Java Island, a mud sample unexpectedly included large numbers of a notorious fish killer, Chattonella-like motile cells, and its resting cysts. These motile cells were established as clonal cultures for further identification and physiological tests. The cysts were examined through palynological and molecular biological means. Identification based on light microscopy and ribosomal RNA gene sequences confirmed that these cells and cysts were Chattonella marina var. marina. While the strains were genetically identical to the temperate strains isolated from Japan and China, temperature experiments showed that the Indonesian strains possessed a high maximum quantum yield of photosystem II even after exposure to 34 °C, a temperature at which the Japanese strain could not survive. Salinity experiments showed adaptation of the strains to a salinity of 15. These findings, together with the discovery of populations of cysts in the mangrove sediment, highlight the tough and unique nature of the Indonesian strains, which are likely adapted to wide fluctuations of temperature and salinity in mangrove swamps, and pose a potential risk to fisheries in Indonesia. [ABSTRACT FROM AUTHOR]

In order to better understand the influence of changing salinity conditions on the trophic transfer of 137 Cs in marine fish that live in dynamic coastal environments, its depuration kinetics was investigated in controlled aquaria. The juvenile turbot Scophthalmus maximus was acclimated to three distinct salinity conditions (10, 25 and 38) and then single-fed with compounded pellets that were radiolabelled with 137 Cs. At the end of a 21-d depuration period, assimilation efficiencies (i.e. AEs = proportion of 137 Cs ingested that is actually assimilated by turbots) were determined from observational data acquired over the three weeks. Our results showed that AEs of 137 Cs in the turbots acclimated to the highest salinity condition were significantly lower than for the other conditions (p < 0.05). Osmoregulation likely explains the decreasing AE observed at the highest salinity condition. Indeed, observations indicate that fish depurate ingested 137 Cs at a higher rate when they increase ion excretion, needed to counterbalance the elevated salinity. Such data confirm that ambient salinity plays an important role in trophic transfer of 137 Cs in some fish species. Implications for such findings extend to seafood safety and climate change impact studies, where the salinity of coastal waters may shift in future years in response to changing weather patterns. [ABSTRACT FROM AUTHOR]

The Northern South China Sea (NSCS) is one of the most important marginal seas in the northwest Pacific Ocean. It receives large amounts of terrestrial inputs, and is affected by intrusion of Kuroshio Water. Dissolved manganese (Mn) can be used as a chemical tracer, facilitating study of fluxes and processes at ocean interfaces. To investigate the behavior and transport of dissolved Mn in the NSCS, we measured the concentrations of dissolved Mn in samples collected in summer 2011 and 2015, during field survey voyages supported by the National Science Foundation of China. The concentration of dissolved Mn ranged from 0.5 to 29.9 nM, with an average of 3.7 nM. Elevated concentrations (>15 nM) of dissolved Mn were found in coastal waters, while low concentrations (<3 nM) were found in areas affected by Kuroshio Water intrusion. There was no significant inter-annual variation in the dissolved Mn concentrations in the study region. Vertical profiles of dissolved Mn in the NSCS were similar to those found in open ocean conditions, with maxima occurring in surface waters and a decrease with depth. Large inputs of dissolved Mn occurred from terrestrial sources to the NSCS coastal areas via the Pearl River. Variations in the distribution of dissolved Mn resulting from intrusion of Kuroshio Water and its interactions with NSCS water were associated with Shelf Water transport. Data on dissolved Mn concentrations across the NSCS slope indicated that the offshore transport of Shelf Water in the upper water layer plays an important role in regulating the distribution of dissolved Mn. A preliminary box model was established to develop a dissolved Mn budget for the NSCS. The flux of dissolved Mn was dominated by exchanges between the NSCS and the northwest Pacific Ocean, with >60% of the material transport flux occurring in the Luzon Strait. [ABSTRACT FROM AUTHOR]

In this study we apply hyperspectral imagery to identify saline blank patterns within the mixed mangrove forest of Sunderban Bio-geographic Province, West Bengal, India. We use derivative analysis to identify hyperspectral wavelengths that are sensitive to the presence of minerals comprising saline blanks. These wavelengths have been considered for development of a novel saline blank identification model. The wavelength showing derivative value with maximum absorption in the SWIR region at 1780 nm and maximum reflection in the red region at 690 nm has been extracted for development of saline blank index. This index has been compared with the existing salinity indices and a detailed analysis has been carried out. It is found that the index outperforms existing salinity indices – normalized differential salinity index and salinity index, and accurately detects the saline blank areas of Henry Island of the Sunderbans Delta. The accuracy of pixels identified as saline blank pixels has been assessed by comparing the overall accuracy with other existing indices. Physical sampling has also been carried out and the salinity results have been compared with the image-derived results. [ABSTRACT FROM AUTHOR]

This paper shows the important role that circulation can play in the long-term variability of thermohaline properties of the bottom layer in the Irminger Sea, and the increase in salinity in the 21st century in spite of intense ice melting in the Arctic and freshening of the upper and intermediate layers that started over the last 5-7 years in the North Atlantic. [ABSTRACT FROM AUTHOR]

Glass objects are common in shipwrecks since they are associated with ordinary glassware or commercial products. The alteration pathologies of historical glasses from two wrecks from the Mediterranean Sea were analyzed to characterize their alteration mechanisms. The results of this research proved that the alteration layers presented a moderate content of Na 2 O, similar to the average salinity of the ocean, and a high content of Al 2 O 3 due to an extremely basic environment during the corrosion process. The biofouling layer protected the glass surfaces. Dark deposits with a high content of MnO were observed in the most instable glass. [ABSTRACT FROM AUTHOR]

Compost salinity is an ongoing concern for compost producers, especially with certain feedstocks and in arid or semiarid regions. Current testing protocols call for sampling and testing ex-situ via 1:5 (w/v) slurries via electrical conductance. For this research an alternate approach has been proposed, the use of portable X-ray fluorescence (PXRF) spectrometry. Adapting methods developed for soil and water salinity analysis via PXRF, elemental data was used as a proxy for the prediction of compost salinity. In total, 74 compost samples were scanned with PXRF followed by traditional laboratory analysis. Results indicated a strong correlation between the datasets (R 2 0.80; RMSE 1.04 dS m −1 ), similar to findings for soil and water salinity. Furthermore, using the same elemental dataset, compost pH was reasonably predicted (R 2 0.63; RMSE 0.35). PXRF has the benefit of being able to be conducted in-situ or in the laboratory. And, multiple chemical parameters of interest can potentially be predicted from the same dataset. In conclusion, PXRF shows promise for rapid, in-situ salinity determination of composted products. [ABSTRACT FROM AUTHOR]

The moderately halophilic bacterium, Virgibacillus halodenitrificans PDB-F2, is able to degrade phenol in high-salinity environment, which copes with external salinity fluctuation by biosynthesis or uptake of compatible solutes. Four putative compatible solutes transport systems BetL, OpuD1, OpuD2 and OpuD3, which belong to betaine-carnitine-choline transporters (BCCT) family, have been predicted from the complete genome sequence of V. halodenitrificans PDB-F2. This study investigated the responses of four transport genes betL , opuD1 , opuD2 and opuD3 to NaCl stress in V. halodenitrificans PDB-F2. Transcriptional analysis showed that betL , opuD1 , opuD2 and opuD3 were induced by NaCl stress, and had specificity for glycine betaine (GB). The maximal induction of four transport genes transcription depended on high salinity plus GB. Exogenous GB afforded effective osmoprotection for V. halodenitrificans PDB-F2 at high salinity, especially at 15% (wt/vol) NaCl. Escherichia coli MHK13 is a mutant strain which is unable to grow at high salt condition. We examined the growth of E. coli MHK13 complemented with each of four transport genes and examined the uptake of GB in cells by 1 H nuclear magnetic resonance ( 1 H NMR) spectroscopy under high salt condition. These data showed that all four transporters were able to transport GB. [ABSTRACT FROM AUTHOR]

The aim of this study is to compared with amounts in per gram and the egg diameters, hatching rates in 25 °C and 30 ° temperatures and 25‰, 030‰, 035‰ salinity of Artemia sp. from four different origins (California, China, Utah and Vietnam). Egg count and diameter measurement was carried out with the use of binocular microscope. The most number of eggs in 1 gram was determined to be from Utah originated Artemia sp. while the least was determined to be from California originated ones. Hatching rates were detected to be the highest at 30°C temperature, 25‰ salinity, at the 18th hour in Vietnam originated Artemia sp. In conclusion, it was detected that the hatching time for Artemia sp. varies depending on the temperature and salinity of the water. [ABSTRACT FROM AUTHOR]

In this experiment, the responses of plant growth, gas exchange parameters, and ion concentration to different levels of irrigation water salinity (ECiw of 0.9, 1.6, 2.7, 4.7 and 7.0 dS·m-1) and leaching fractions (LFs of 0.17, 0.29) were investigated in hot pepper plants. The pot experiment was conducted using a completely randomized block design with four replications in a rain shelter. Results showed that the height of the hot pepper plants decreased as the ECiw was increased from 25 d after transplanting (DAT) and increased when the LF was increased from 55 DAT. Neither the ECiw nor the LF influenced the root length. An increase in the ECiw caused the suppression of the stem diameter (SD); leaf length; leaf area; leaf chlorophyll content (CCI); dry biomass of roots, stems, and leaves; net photosynthesis (Pn); stomatal conductance (gS); transpiration rate (Tr); and intercellular CO2 concentration (Ci). An increase in the LF caused the SD, leaf length, leaf area, and dry biomass of stems and leaves to increase. However, the dry biomass of roots and the Pn, gS, Tr, and Ci were not significantly affected by the LF, except for the Ci measured on 23 DAT and the Tr on 76 DAT. The Na+ concentrations in the roots and stems increased, whereas the K+/Na+ ratios decreased as the ECiw increased. An increase in the LF led to a decrease in the Na+ concentration of the roots and stems, whereas there was an increase in the K+ concentration in the stems and the K+/Na+ ratios in the roots and stems. Collectively, an increase in the ECiw had an adverse effect on plant growth and gas exchange and led to the accumulation of the Na+ concentration in the roots and stems, whereas an increase in the LF enhanced plant growth, leaf transpiration, and K+ concentration and reduced the accumulation of the Na+ concentration in the roots and stems. We suggest that higher quantity of water should be applied in higher saline irrigation for satisfactory performance for hot pepper growth. [ABSTRACT FROM AUTHOR]

The change from deep-rooted grass and shrub vegetation to annual-cropping dryland farming has contributed to serious soil salinization challenges on the semi-arid North American Great Plains. In some cases, cultivation of the Great Plains has increased the availability of water, causing dominant sulfate salts to travel from the uphill areas to depressions where it will surface when water evaporates at the soil surface. A potential solution could include the replanting of the native deep-rooted vegetation, which requires knowledge of the spatial distribution of soil salinity. This study tested the soil factors influencing electromagnetic-induction meter (EM38) readings of soil salinity distribution around wetlands. The objectives were to: (1) predict growth and survival of Salix dasyclados Wimm. (cv. ‘India’) along a salinity gradient in a small wetland, and (2) investigate whether newly established willows affected water-table fluctuations, which would indicate their phreatophytic nature or their ability to obtain their water supply from the zone of saturation. Results indicated significantly lower salinity values for sampling points with EM38 readings above 175 and 250 mS m−1 for height and survival, respectively. In addition, diurnal fluxes of the water table in areas of good willow growth and lower salinity indicated that cultivar ‘India’ was phreatophytic in these areas and therefore has great potential for being used to combat saline seeps. [ABSTRACT FROM AUTHOR]

Natural springs have the potential to provide important information on hydrogeochemical processes within aquifers. This study used traditional and classic technical methods and procedures to determine the characteristics and evolution of springs to gain further knowledge on the differences between hot saline springs and cold fresh springs. In a short river segment near Wenquanzhen in the eastern Sichuan Basin, southwest China, several natural springs coexist with total dissolved solids (TDS) ranging from less than 1 to 15 g/L and temperatures from 15 to 40 °C. The springs emanate from the outcropping Lower and Middle Triassic carbonates in the river valley cutting the core of an anticline. The cold springs are of Cl·HCO3-Na·Ca and Cl·SO4-Na types, and the hot saline springs are mainly of Cl-Na type. The chemistry of the springs has undergone some changes with time. The stable hydrogen and oxygen isotopes indicate that the spring waters are of a meteoric origin. The salinity of the springs originates from dissolution of minerals, including halite, gypsum, calcite and dolomite. The evolution of the springs involves the following mechanisms: the groundwater receives recharge from infiltration of precipitation, then undergoes deep circulation in the core of the anticline (incongruent dissolution of the salt-bearing strata occurs), and emerges in the river valley in the form of hot springs with high TDS. Groundwater also undergoes shallow circulation in the northern and southern flanks of the anticline and appears in the river valley in the form of cold springs with low TDS. [ABSTRACT FROM AUTHOR]

Mycosporine‐like amino acids (MAA) are ultraviolet screen substances synthesized by marine algae. The physiological function of these substances is related to cellular protection against UV radiation and as a protective mechanism against oxidative stress. These substances can be found mainly in the ocean, among red seaweeds. Its concentration in organisms has been related to ultraviolet radiation and availability of inorganic nitrogen in the environment. We start our study of MAA content in different species to understand if environmental conditions influence the concentration of MAAs in red seaweeds. The Brazilian coast presents abiotic factors that interact to create different physical‐chemical features in the environment. We collected 441 samples from 39 species of red seaweed easily found in the intertidal zone, in low tide, during the summer of 2015. The sampling encompassed a latitudinal gradient (3° S to 28°5′ S) at 23 points along the coast. We quantified and identified the content of MAAs in species through the method of high performance liquid chromatography. We detected for the first time the occurrence of MAAs in certain species of red algae that have not been reported to contain MAAs before. We confirmed that some environmental factors influenced the content of MAAs. Enhanced MAA contents, for example, were found in environments with a basic pH, a high ultraviolet index, and high concentrations of phosphate and nitrate. Salinity, dissolved oxygen and variations of sea surface temperature also influenced, in a secondary way, MAA content in algae in their natural environments. [ABSTRACT FROM AUTHOR]

ABSTRACT Costa, M.S.; Rocha, A.S.; Santos, A.S., and Rolnic, M., 2018. Influence of tide on salt entrapment in the River Mojuim Estuary. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 81–86. Coconut Creek (Florida), ISSN 0749-0208. The aim of this study is to check whether there is salt entrapment in an estuary in the Amazon eastern coast. This study case was conducted in a section of the lower Mojuim River estuary. Tide, current, and water salinity were measured for 25 h during wet and dry seasons, 2014. Tide and salinity levels were recorded at fixed stations for 55 consecutive days during each season. Advective, diffusive, and dispersive salt transport and the Stratification/Circulation diagram were calculated. The Mojuim River estuary has a macrotidal, semidiurnal regime, with tide height of 4.9 m during spring tide and 3.2 m during neap tide. Maximum current intensities during wet season are 1.6 m.s−1 in flood tide and 1.9 m.s−1 in ebb tide, whereas during dry season, they are 1.2 m.s−1 in ebb tide and 1.6 m.s−1 in flood tide. Mean salinity increased from 7.3 g.kg−1 (±2.82) during wet season to 21.2 g.kg−1 (±3.62) during dry season. Advective salt transport was 736.4 kg.s−1 during wet season and 72.1 kg.s−1 during dry season, up-estuary and down-estuary, respectively. River discharge and Stokes transport are the predominant components of advective salt transport. It allows salt entrapment in the estuary during extreme tides, which might be retained in the floodplains. As the Mojuim river estuary is shallow (mean depth 4.5 m), the water column varies according to the fluvial component and to tides. Thus, the intensity of the fluvial component and tides during wet season promotes eddy mixture. During dry season, a decreased fluvial component due to low rainfall increases saline intrusion and causes the water column to be slightly stratified. The Mojuim river estuary was classified as well mixed during wet season and slightly mixed during dry season, according to the Stratification/Circulation diagram. [ABSTRACT FROM AUTHOR]

Low salinity water flooding appears to be a cost-effective and environmentally friendly means to shift wettability of oil/brine/rock system towards more water-wet, thus improving hydrocarbon recovery. While the contribution of kaolinite (edge-charged clays) on low salinity effect has been extensively investigated, how basal-charged clays (e.g., illite, smectite, and chlorite) contributing to the low salinity effect remains unclear. We thus hypothesize that low salinity water facilitates ion exchange in the presence of basal charged clays, thus lifting off oil films from pore surfaces. To test the hypothesis, we performed a geochemical study using PHREEQC in light of double layer diffuse theory. We quantitatively interpreted the pH increase and low salinity effect from corefloods conducted by RezaeiDoust et al. [RezaeiDoust A, Puntervold T, Austad T. Chemical verification of the EOR mechanism by using low saline/smart water in sandstone. Energy & Fuels. 2011;25(5):2151–62.]. We demonstrate that low salinity water triggers a pH increase at the presence of basal-charged clays, thus a more water-wet because of ion exchange. We therefore expand the application envelope of low salinity water flooding to reservoirs with basal-charged clays. [ABSTRACT FROM AUTHOR]

An optical fiber sensor is fabricated and characterized in this communication for salinity detection. The proposed sensor consists of a multimode fiber (MMF) and a section of no core fiber (NCF) with a round tip. The sensor detects the intensity variation of the back reflected light caused by changing concentration of the salt solution surrounding the probe. The parameters of the sensor were studied for better performance. A down tapering is also introduced to enhance the sensitivity of the sensor and a high sensitivity of 0.773 dB/% is obtained for a salinity range of 0–20%. Due to its high sensitivity, low cost and compact size, the proposed sensor can be very much useful in water quality monitoring for environmental, healthcare and industrial applications. [ABSTRACT FROM AUTHOR]

The use of a hydrate-based technology in seawater desalination is an interesting potential hydrate application since salt ions would be excluded from the hydrate crystal lattice. In order to better understand the hydrate-based desalination process, experiments have been conducted using cyclopentane (CyC5, sII) hydrates, which can be formed at atmospheric pressure and temperatures below 7.7 °C. The hydrate formation experiments were performed at various subcoolings for aqueous solutions with different salinities in a bubble column. The hydrate formation times decreased and the hydrate conversion increased with increasing subcooling and agitation. Various hydrate-former injection methods were studied, with the most effective method involving spraying finely dispersed CyC5 droplets (around 5 µm in diameter) into the water-filled bubble column. The latter method resulted in a 2-fold increase in seawater conversion to hydrate crystals compared with injecting millimeter-scale CyC5 droplets. A desalination efficiency of 81% (the salinity decreased from 3.5 to 0.67 wt %) was achieved by using a three-step separation method, including gravitational separation, filtration, and a washing step. Washing the hydrate sample using filtered water decreased the salinity from 1.5 wt % in the solid hydrates before washing to 1.05 wt % after washing. [ABSTRACT FROM AUTHOR]

A new sensing method for simultaneous measurement of seawater temperature and salinity by C-type micro-structured fiber was proposed. The C-type fiber structure formed by removing the outer wall of one pore from a six holes micro-structured fiber, which would bring in birefringence and broke original pattern of degeneracy. By optimizing the parameters of this fiber structure, X polarization and Y polarization of fundamental mode were separate. Therefore, it could be used for double parameter measurement. Besides, gold film coated on the surface of structure to enhance sensing sensitivity by Surface Plasmon Resonance (SPR) principle. In this study, finite element analysis method was used to analyze the spectral transmission characteristics of C-type micro-structured optical fiber. The surface of wedge-shaped defect was contacted with seawater directly to feel salinity; meanwhile, thermo-optic material filled into pores to detect the temperature of seawater. Through model analysis, it was proved that the proposed filling structure could produce two SPR loss valleys, which had different responses to temperature and salinity. Under optimized structure, maximum salinity sensitivity of 1.402 nm/‰ was obtained for X-polarization and maximum temperature sensitivity of −7.609 nm/ °C was obtained for Y polarization, which demonstrated that the designed scheme could not only solve the cross sensitivity problem of two parameters but also achieve high sensitivity. In addition, C-type micro-structured fiber is non-cascade integrated, strong stability, and flexibility in design, which has great potential for sensing applications. [ABSTRACT FROM AUTHOR]

Delayed arrival of the oil bank and reduced injectivity are risks which are commonly associated with low salinity polymer (LSP) flooding. In this study, experimental work was carried out to address these risks; the polymer retention and the cationic exchange in the presence of polymer were the main subjects of investigation. Single phase coreflood experiments were performed, where low and high salinity polymer (HSP) solutions, i.e., conventional polymer flood using formation brine, were injected in reservoir core plugs. The performance of the two polymer solutions were analyzed for polymer retention, injectivity and polymer acceleration. Compared to the HSP coreflood, the LSP coreflood showed considerably lower polymer retention and better long-term injectivity. There was no delay in polymer breakthrough, and the polymer acceleration was comparable to HSP floods. Analysis of produced effluent of the LSP coreflood detected divalent ion concentrations higher than the injected solution, and the solution which was already in equilibrium with the rock. This suggested that the divalent ions were released from the rock into the solution because of cation exchange in the presence of the LSP solution. Such increase in divalent ion concentration increased the polymer solution salinity and resulted in a viscosity loss. The results of the experimental study indicated that LSP flooding can be an attractive alternative to conventional polymer flooding, although viscosity loss due to cation exchange is a subject for further de-risking work. A numerical model which couples the cation exchange in presence of polymer with flow dynamics in core scale has also been developed. The flow field was used to advect the polymer which influenced the equilibrium condition between the rock surface and the solution. We present preliminary results obtained using the model which can be used to gain insights and study sensitivities around different geochemistry coupled flow processes. [ABSTRACT FROM AUTHOR]

Polymer gel is often used to reduce flow through highly conductive fracture networks, frequently present in naturally fractured carbonate reservoirs. When in place, polymer gel efficiently reduces fracture flow and may improve sweep efficiency and oil recovery during water chase-floods. Polymer gel treatments have in some cases been less efficient than expected in reducing fracture conductivity. This may occur because the polymer gel only partially fills the fracture volume, and allows fracture channeling of injected fluids. Low-salinity waterfloods may improve polymer gel blocking of fractures and remedy less efficient polymer gel treatments. Previous experimental work has shown that low-salinity waterfloods, where the salinity is reduced with respect to the gel solvent, reduces fracture channeling and restores matrix flow. This work further investigates low-salinity waterflooding as a method to improve conformance during polymer gel treatments in fractured, low permeable, carbonate rock. The low flow capacity of carbonate may cause a less efficient gel blocking of fractures, although the gel behaves according to established models during injection. Low-permeable carbonate core plugs with open, highly conductive fractures were used for this study. Water flow paths during high-salinity and low-salinity waterflooding were evaluated by positron emission tomography (PET). We found that gel blocking efficiency during chase waterfloods depends on: 1) the salinity of the chase water. Gel blocking efficiency increases with low-salinity water throughput; opposite to high-salinity waterfloods, where the gel blocking is reduced with water throughput. 2) The core material. As expected, a higher pressure was required to maintain flow through the matrix during water chase-floods in low-permeable carbonates. Water was diverted into the matrix for all ranges of permeability: sandstone and low-permeable carbonates, during low-salinity waterfloods. 3) The presence of oil. Fracture channeling prevailed during low-salinity waterfloods in chalk cores with residual oil present. [ABSTRACT FROM AUTHOR]

The low salinity effect in clay-rich outcrop sandstones is probed by micro-CT imaging and analysis. A set of eight Berea sandstone mini-plugs underwent primary drainage and aging in crude oil to a mixed-wet state, followed by spontaneous imbibition of high and low salinity brines and imaging of this sequence of prepared starting and endpoint states. Tomogram registration and analysis were used to determine the salinity-induced changes in oil volume, oil/rock and oil/brine interfacial areas, and oil/brine interfacial mean curvature. Pore-scale statistics were extracted to explore any local correlation between the low salinity effect and pore geometry/topology. The qualitative observations and quantitative analyses demonstrated that the small oil recovery by the low salinity effect corresponded to a slight shift towards water-wet. [ABSTRACT FROM AUTHOR]

Low-salinity waterflooding attempts to improve recovery by reducing the salinity of the injection water, where the wettability alteration towards more water-wet state of the reservoir rock is believed to be the leading mechanism. This technology has received significant interest and a rich body of unsteady-state coreflooding test data has been reported in the past few years. However, capillary end-effect driven artifacts in conventional unsteady-state coreflooding could hinder proper understanding and interpretation of the measured results. We have developed a modified steady-state fractional-flow method to minimize capillary end effects. The fractional-flow analysis and simulation illustration of the new method has been published earlier by Gupta et al. (2015). In this work, we applied this new method to several Middle East carbonate reservoirs where slight changes in relative permeability consistent with a change in wettability can be observed but the overall uplift in recovery was very small. In addition, the results from the new method and the conventional coreflooding method were compared in selected cases to demonstrate the benefit of the new method in minimizing capillary end effect artifacts. Overall, this work demonstrates an improved laboratory screening methodology for low-salinity waterflood and similar EOR methods. The results of this work highlight the potential as well as challenges in low-salinity waterflooding in carbonates as a practical EOR technology. [ABSTRACT FROM AUTHOR]

Pore-level oil mobilization is studied during low salinity waterflooding by microscopic visualization of water diffusion and osmosis in sandstone silicon-wafer micromodels. The two-dimensional water-wet micromodels apply a controlled, state-of-the-art experimental approach, with a high accuracy pore network, sharp edges and surface roughness to observe transport and displacement processes during low salinity waterflooding. Residual and capillary trapped oil is mobilized when a salinity contrast is established between high-saline connate brine in matrix and low salinity water flowing in an adjacent fracture. The driving force is the difference in chemical potential between the aqueous phases. The focus of this work is on water transport by diffusion and osmosis, mechanisms that are both present in low salinity waterflooding, but less reported in literature. The micromodel system makes it possible to distinguish diffusive and osmotic effects from other well-known mechanisms such as wettability change and fines migration. Transport of water occurs by diffusion through film-flow resulting in film-expansion along water-wet grains. In presence of an osmotic gradient the oil-phase act as a semi-permeable membrane allowing transport of low salinity water into high-saline water-in-oil emulsions. [ABSTRACT FROM AUTHOR]

The goal of this paper is to quantify the atmospheric influence, i.e. the influence of wind in particular, on the sea dynamics in the Rijeka Bay (Adriatic Sea). This quantification is important for city sewage disposal and dispersion as well as surface pollution dispersion. We compare the effect of jugo (sirocco) and bora winds on a calm period. The resulting simulations show that the bora conveys the surface layer of sea water out of the bay through the Middle and the Great Gate while deep cold water enters the bay through the same gates. The mean vertical upward velocity component close to the coast is about 1 mm s-1. This is sufficient to rise cold water near the city of Rijeka to the surface in three hours and to significantly cool the surface layer during summer. For the south-east wind (jugo) the situation is reverse: the warmer surface sea water enters the bay through the Middle and the Great Gate, while the colder bottom sea water exits the bay through the Middle and the Great Gate, accumulating the warmer sea water in the bay. In the case of no wind the surface velocity vectors (at depths of 0.5 m) are disordered and do not follow any particular pattern while the movements at 12 m, 24 m, 36 m, 48 m, and 60 m show dominant flow from the western coast (of the island Krk) toward the eastern coast of the Istrian peninsula. [ABSTRACT FROM AUTHOR]

Pretreatment in arboriculture is a new physiological approach allowing the improvement of plant tolerance to salt stress. This research aims to screen various pretreatments of salicylic acid (SA) and/or calcium chloride (CaCl 2 ) to mitigate the effect of salinity on ‘Oueslati ’ olive plants ( Olea europeae L.) on physiological attributes under 200 mmol L −1 of NaCl application. One - year- old plants were transplanted to sand culture in a greenhouse, and were pretreated with two levels of foliar application of SA (0.5 and 1 mmol L −1 ) and by adding CaCl 2 (10 and 20 mmol L −1 ) to the culture solution twice a week for 45 days. At the end of the pretreatment, the plants were subjected to 200 mmol L −1 NaCl exposure for 75 days. The result showed that shoots and roots growth were decreased significantly due to salinity, sodium (Na + ) ions increased and K + /Na + ratio decreased in leaves. Rate of assimilation ( A ), transpiration ( E ) and stomatal conductance ( g s ) decreased in leaves. Salinity caused significant increase in both malondialdehyde (MDA) and H 2 O 2 concentration, a decrease in total polyphenol and flavonoid levels and an increase in scavenging activity (IC50) (21%). Moreover, salinity caused a decrease in xylem and an increase in phloem thickness in leaves. However, pretreatments could partly improve the adverse effects of salinity on the most studied parameters. SA (1 mmol L −1 ) is able to restrict Na + ions transport from the roots to the leaves limiting its toxicity in the sensitive organs. SA (1 mmol L −1 ) and CaCl 2 (10 mmol L −1 ) pretreatment alleviate the effects of salinity on dry weight of shoots and roots as well as, photosynthetic activity in pretreated plants. Moreover, at the same pretreatment, results showed a decrease of the Na + translocation to the leaves. Furthermore, it has been shown that pretreatment of ‘Oueslati’ olive plants enhance the non-enzymatic antioxidant activity (total polyphenol and flavonoid content).These results suggest that pretreatments may be useful methods to increase salt tolerance in olive, for use in arid and semi-arid environments. [ABSTRACT FROM AUTHOR]

Natural gas hydrates are found widely in oceanic clay-rich sediments, where clay–water interactions have a profound effect on the formation behavior of gas hydrates. However, it remains unclear why and how natural gas hydrates are formed in clay-rich sediments in spite of factors that limit gas hydrate formation, such as small pore size and high salinity. Herein, we show that polarized water molecules on clay surfaces clearly promote gas hydrate nucleation kinetics. When water molecules were polarized with an electric field of 104 V/m, gas hydrate nucleation occurred significantly faster with an induction time reduced by 5.8 times. Further, the presence of strongly polarized water layers at the water–gas interface hindered gas uptake and thus hydrate formation, when the electric field was applied prior to gas dissolution. Our findings expand our understanding of the formation habits of naturally occurring gas hydrates in clay-rich sedimentary deposits and provide insights into gas production from natural hydrate deposits. [ABSTRACT FROM AUTHOR]

Sea level rise and upstream development is causing salinity intrusion in Vietnam’s Mekong River Delta (MRD) and, as a consequence, agricultural productivity is declining. As the Vietnamese government and local communities search for a solution, it has become apparent that there are insufficient public resources to build the dykes necessary to control this problem. So, we employ a referendum contingent valuation methodology (CVM) to determine whether or not farm households might be willing to pay for part of the cost of a salinity intrusion risk reduction program. We find that farm households are willing to contribute funds to such a program. In areas where salinity intrusion is already reducing productivity, farm households are willing to contribute US$2.58 per month. In areas where salinity intrusion is expected to be reducing productivity by 2030, willingness to contribute is US$1.99 per month. Surprisingly, in MRD areas where salinity intrusion is not expected within the next 15 years, willingness to contribute remains positive at US$1.32 per month. These findings have local, national and international implications that require careful consideration. In passing, we make a methodological observation that a treatment model including ‘do not know’ responses provides consistent results with conventional referendum elicitation procedures. [ABSTRACT FROM AUTHOR]

The use of electrical conductivity (EC) as a water quality indicator is useful for estimating the mineralization and salinity of water. The objectives of this study were to explore, for the first time, extreme learning machine (ELM) and wavelet-extreme learning machine hybrid (WA-ELM) models to forecast multi-step-ahead EC and to employ an integrated method to combine the advantages of WA-ELM models, which utilized the boosting ensemble method. For comparative purposes, an adaptive neuro-fuzzy inference system (ANFIS) model, and a WA-ANFIS model, were also developed. The study area was the Aji-Chay River at the Akhula hydrometric station in Northwestern Iran. A total of 315 monthly EC (µS/cm) datasets (1984–2011) were used, in which the first 284 datasets (90% of total datasets) were considered for training and the remaining 31 (10% of total datasets) were used for model testing. Autocorrelation function (ACF) and partial autocorrelation function (PACF) demonstrated that the 6-month lags were potential input time lags. The results illustrated that the single ELM and ANFIS models were unable to forecast the multi-step-ahead EC in terms of root mean square error (RMSE), coefficient of determination (R2) and Nash–Sutcliffe model efficiency coefficient (NSC). To develop the hybrid WA-ELM and WA-ANFIS models, the original time series of lags as inputs, and time series of 1, 2 and 3 month-step-ahead EC values as outputs, were decomposed into several sub-time series using different maximal overlap discrete wavelet transform (MODWT) functions, namely Daubechies, Symlet, Haar and Coiflet of different orders at level three. These sub-time series were then used in the ELM and ANFIS models as an input dataset to forecast the multi-step-ahead EC. The results indicated that single WA-ELM and WA-ANFIS models performed better than any ELM and ANFIS models. Also, WA-ELM models outperformed WA-ANFIS models. To develop the boosting multi-WA-ELM and multi-WA-ANFIS ensemble models, a least squares boosting (LSBoost) algorithm was used. The results showed that boosting multi-WA-ELM and multi-WA-ANFIS ensemble models outperformed the individual WA-ELM and WA-ANFIS models. [ABSTRACT FROM AUTHOR]

Oil recovery from carbonate reservoirs is usually low due to their extreme heterogeneity caused by natural fractures and the nature of the oil-wet matrix. Low salinity water flooding (LSWF) and preformed particle gels (PPG) control conformance are two novel technologies that have recently drawn great interest from the oil industry. Theoretically, LSWF can only increase displacement efficiency, and it has little or no effect on sweep efficiency; PPG can plug fractures, they can improve sweep efficiency, but they have little effect on displacement efficiency. We developed a cost-effective, novel, enhanced oil recovery (EOR) technology for carbonate reservoirs by coupling the two technologies into one process. The objective of this paper is to provide a comprehensive understanding of the combined technology and to demonstrate how the coupling method can improve oil recovery. The oil-wet carbonate cores provided a higher improved oil recovery than water-wet carbonate cores during LSWF. The decrease in fracture width resulted in a higher oil recovery factor. Compared to traditional bulk gel treatments, PPG forms stronger plugging but will not form an impermeable cake in the fracture surface; therefore, PPG allows low salinity water to penetrate into the matrix to modify its wettability, thereby producing more oil from the matrix. Results also show that oil recovery increased by 10% during LSWF after the second water flooding. Additionally, when PPGs were injected, another 4% of oil recovery was gained. As a result, the combined LSWF and PPG increased oil recovery by 18%. A full-factorial experimental design was performed to investigate the influence of the PPG-placed injection pressure (which refers to the maximum pressure used to inject PPG for each experiment), water salinity, and fracture width. Experimental results tell that PPG-placed injection pressure is the factor that strongly influences both oil recovery factor and residual resistance factor; fracture width is the least influential factor among the three. Experimental results prove that the coupled method bypasses the limitations of each method when used individually and improves both displacement and sweep efficiency. [ABSTRACT FROM AUTHOR]

Oily water of high salinity and temperature causes challenges to eco-environment. Instead of being considered as only pollutants treated by integrated membrane system, oily water was also considered and utilized as driving-energy resource for the system in this work. This paper proposed and studied integrated UF-FO-MD system for not only treatment of oily water but also utilization of its high salinity and temperature (i.e., osmotic and thermal energies). 50 kDa ceramic membrane was selected for oily water treatment because of high oil recovery rate, low flux decline rate and great reduction of downstream FO-MD fouling, and corresponding membrane fouling mechanism was proposed. After UF, oily water was simultaneously used as FO draw (sewage as FO feed) and MD feed to utilize its osmotic and thermal energies for FO-MD running. Oil content largely influenced FO-MD fouling, while temperature and salt content had little influence. Three scenarios of dynamic mass-transfer process and temperature-salt content equilibrium curve for FO-MD were proposed, which provide guidance for oily water utilization to control mass-transfer process. UF-FO-MD system efficiently treated both oily water and sewage, and recovered high-quality water by utilization of oily water energies at low-energy cost. Oily water after treatment and utilization met reinjection standard. This work helps for oil-field wastewater treatment and utilization to realize water recovery, energy utilization and pollution reduction. [ABSTRACT FROM AUTHOR]