High-salinity Seawater Research Articles

Self-Assembled Nanofibers for Strong Underwater Adhesion: The Trick of Barnacles.

Developing adhesives that can function underwater remains a major challenge for bioengineering, yet many marine creatures, exemplified as mussels and barnacles, have evolved their unique proteinaceous adhesives for strong wet adhesion. The mechanisms underlying the strong adhesion of these natural adhesive proteins provide rich information for biomimetic efforts. Here, combining atomic force microscopy (AFM) imaging and force spectroscopy, we examine the effects of pH on the self-assembly and adhesive properties of cp19k, a key barnacle underwater adhesive protein. For the first time, we confirm that the bacterial recombinant Balanus albicostatus cp19k (rBalcp19k), which contains no 3,4-dihydroxyphenylalanine (DOPA) or any other amino acids with post-translational modifications, can self-assemble into aggregated nanofibers at acidic pHs. Under moderately acidic conditions, the adhesion strength of unassembled monomeric rBalcp19k on mica is only slightly lower than that of a commercially available mussel adhesive protein mixture, yet the adhesion ability of rBalcp19k monomers decreases significantly at increased pH. In contrast, upon preassembly at acidic and low-salinity conditions, rBalcp19k nanofibers keep stable in basic and high-salinity seawater and display much stronger adhesion and thus show resistance to its adverse impacts. Besides, we find that the adhesion ability of Balcp19k is not impaired when it is combined with an N-terminal Thioredoxin (Trx) tag, yet whether the self-assembly property will be disrupted is not determined. Collectively, the self-assembly-enhanced adhesion presents a previously unexplored mechanism for the strong wet adhesion of barnacle cement proteins and may lead to the design of barnacle-inspired adhesive materials.

„Oázis a sivatagban” — különösen gazdag ősmaradvány-együttes a fosszíliaszegény üllési Szegedi Dolomitból

A Szegedi Dolomit Formációba sorolt sötétszürke, breccsásodott dolomit a Szegedi-medence legjellegzetesebb mezozoos képződménye. Jellemzője a több fázisú dolomitosodás és átkristályosodás, ami magyarázza az ősmaradványok rossz megtartását és szegényességét. Jelen munkánkban egy kivételesen gazdag és jó megtartású ősmaradvány-együttes vizsgálati eredményeiről számolunk be. Az Üllés–18 fúrás 6. mf kőzetanyagából készült vékonycsiszolatokban Hoyenella–Glomospirella–Glomospira dominanciájú foraminifera-együttes mellett alga telepfoszlányokat és ostracoda kettős teknőket is megfigyeltünk. Aminta különlegességét egy Megalodontidae kagyló juvenilis példánya adja. A kőzet mikrofáciese és ősmaradvány-együttese középső-triász, felső-anisusi–ladin korú, megnövekedett sótartalmú, sekélytengeri, zátonyháttér–lagúna környezetet valószínűsít. A bepárlódott, magas sótartalmú tengervíz szerepet játszhatott a formáció dolomitosodásában.

Colorimetric determination of uranyl ([formula omitted]) in seawater via DNAzyme-modulated photosensitization

Various DNA-modulated photosensitization schemes have been reported for various applications, but DNAzyme has not yet been included. Here, we found the DNAzyme with metal ion as cofactor could also be efficient in modulation of photosensitization process. The UO22+-specific DNAzyme can switch between double strand DNA (dsDNA) and single strand DNA (ssDNA) upon UO22+ cleavage, which can regulate the photosensitization process of SYBR Green I. Coupling with photosensitization-induced chromogenic reaction (TMB oxidation), a simple colorimetric sensor for UO22+ was developed accordingly. To increase the visual resolution of the proposed assay, a background color was supplied. Compared with the previous DNAzyme-based UO22+ sensors, the proposed assay featured label-free and simple. Besides, the tolerance for high salinity of this assay is appealing. The proposed assay offered a detection limit of 0.08 μg/L with UV−vis detection and 0.5 μg/L with the naked eye. With the proposed colorimetric assay, UO22+ levels in the range of 0.7–1.2 μg/L (2.9–5.0 nM) were identified in high salinity seawater samples, with spike-recoveries ranging from 93% to 104%.

The existence of microplastic in Asian green mussels

Due to resistance of polymer as basic properties of plastic, several studies have been conducted to understand the fate of plastic debris in the marine environment. Degradation is the most important process to control distribution of plastic debris a long the marine environment until the existence of plastic in the food chain. The physical and chemical changes of plastic because of degradation process will lead to the release of polluted substances which eventually more toxic for the environment. Furthermore, when plastic degraded become a microplastic will lead to easy ingested by biotic such as mussell which commonly consumed by humans. The aim of this research was to investigate the concentration of microplastic adsorbed and ingested by mussels considering characteristic of sea water. About 30 samples have been collected from 3 different locations that is brackish water (31 ppb), high salinity (36 ppb) and low salinity (33 ppb) for measuring a number of microplastic in mussels on three different salinity. The result of microstructure analysis by microscope showed that mussel evaluated from the marine environment contaminated by microplastic with average size of 211.163 μm. In high salinity sea water, microplastic found in mussel was greater than low salinity and brackish water. The SEM/EDX analysis showed the presence of SIO2 0.14 % (w/w), Na2O 24.27 %(w/w) and Al2O3 0.27 % (w/w) in the microplastic obtained in the mussel indicating the components which are mostly found in the plastic industries. The amount of microplastic in mussell could be used as pollution indicator in the marine environmental by plastic waste.

Comparison of PCL degradation in different aquatic environments: Effects of bacteria and inorganic salts

Six different water bodies of different salinities and bacteria were set up to study the effects of microorganisms and salts on the degradation process of biodegradable polycaprolactone (PCL) spline. The experimental data for a 52-week period consistently indicate that both microorganisms and salts have an impact on the degradation process. PCL shows slow bulk hydrolysis in aseptic water and relatively rapid interfacial enzymatic degradation in bacteria-containing water however. The degradation rate of PCL in lab-prepared high-salinity seawater was noticeably higher than that in distilled water and low-salinity seawater, indicating a salt-driven acceleration of PCL hydrolysis. Because of the combined effects of factors such as the presence of bacteria, salinity, and external forces in the sea, PCL degrades fastest in natural seawater, losing 29.8% of its original weight in 52 weeks.

Insight into the stability of hydrophilic silica nanoparticles in seawater for Enhanced oil recovery implications

The stability of nanoparticles in the aqueous phase is a major challenge in the application of nanoparticles in Enhanced Oil Recovery (Nano-EOR) processes. Previous studies evaluated the performance of nanoparticles for EOR purposes; either deionized water or water at very low ionic strength was used. Nanoparticles can be easily dispersed in the deionized or low salinity water, whereas they are extremely unstable in high salinity seawater or formation water. Typically, seawater or formation brine is injected for water-flooding and EOR purposes. If we want to change the fluid–fluid or fluid-rock properties by injecting nanoparticle enhanced water, then, the stability of the nanoparticles in high salinity water is extremely important. In this work, a novel and simple method to stabilize silica nanoparticles in seawater is proposed. First, the aggregation of silica nanoparticles in the presence of different ions is investigated. The results show that the presence of positive multivalent ions in the electrical double layer around nanoparticles can destabilize silica nanoparticles. In order to reduce the concentration of positive multivalent ions around silica nanoparticles, a theory based on “H+ protection” is proposed and its effectiveness is tested by particle size, turbidity, zeta-potential, and pH measurements. The effect of the concentrations of nanoparticles and HCl on the stability of silica nanoparticles in seawater is evaluated. Experimental results show that H+ protection, which can be obtained by adding HCl to the solution, can effectively stabilize silica nanoparticles in seawater. The experiments show that the size of nanoparticles in the seawater directly depends on the concentration of nanoparticles and inversely to the HCl concentration.

Energy efficiency of RO and FO–RO system for high-salinity seawater treatment

Forward Osmosis (FO) has been proposed as an alternative method for seawater desalination, wherein Reverse Osmosis (RO) membrane technology is used for regeneration of the draw solution. Previous studies have indicated that a standalone Reverse Osmosis unit is more energy efficient than a Forward Osmosis-Reverse Osmosis system and as such it was recommended that an FO-RO system was best employed only for the desalination of high salinity seawaters. This study examined FO-RO applicability in more detail by examining the impact of seawater salinity, impact of an Energy Recovery Device (ERD), and the effect of membrane fouling. For comparison purposes, the performance of the FO process was improved to minimize the impact of concentration polarization and optimize the concentration of draw solution. Model calculations revealed that FO-RO was more energy efficient than RO when no Energy Recovery Device was employed. However, results showed there was no significant difference in the power consumption between the FO-RO system and the RO unit at high seawater salinities, particularly when a high efficiency ERD was installed. Moreover, the FO-RO system required more membrane area than conventional a RO unit which may further compromise the FO-RO desalination cost.

Flux stabilization in membrane distillation desalination of seawater and brine using corrugated PVDF membranes

Due to its tolerance of high salinities, membrane distillation (MD) is promoted for desalination of challenging high salinity seawater and for brine recovery and reduction in seawater desalination plants. In these applications, fouling of MD has recently been shown to become more pronounced, although much less than for reverse osmosis. In this study, a two-layer corrugated composite flat sheet polyvinylidenefluoride (PVDF) membrane was fabricated, characterized and tested in a lab-scale direct contact MD (DCMD) system for improved flux stabilization. The first membrane layer was used to control the pore size while the second was devoted for formation of surface corrugation and enhancing hydrophobicity. Tested using seawater and concentrated brine against a non-corrugated composite membrane, the corrugated composite membrane showed much higher flux stability identified by only 10.7% reduction in permeate flux after 103h of operation, compared to 66.6% reduction for the non-corrugated membrane. DCMD experiment with concentrated brine proved the effectiveness of corrugations even at high brine concentrations, where the corrugated membrane performed as well as it did with seawater, while the non-corrugated membrane showed even worse performance reaching almost zero flux after 93h of operation. SEM images of the post-MD membranes also confirmed the advantage of corrugations over the flat surface, where the corrugated membrane experienced small amount of salts deposition leaving most of the membrane pores open while the non-corrugated membrane experienced severe scaling and salt depositions forming a thick layer at the membrane surface, blocking most of its pores.

Altered seawater salinity levels affected growth and photosynthesis of Ulva fasciata (Ulvales, Chlorophyta) germlings

Seawater salinity is greatly influenced by tide, evaporation and rain falls. In this study, we investigated the growth and photosynthetic responses of zygote-derived Ulva fasciata Delile germlings to short-term (minutes) and prolonged (days) exposure to different salinity gradients, to evaluate the effect of salinity variation on the early stage of life history in this seaweed. The results showed that, the maximum net photosynthetic rates (NPRm) of U. fasciata germlings was observably decreased in desalted (25 and 15) and high (45) salinity seawater in short-term exposure tests (in minutes). However, after 30 min, the photosynthesis activity in medium salinity (25) was maintained at a relative high level (above 70%). After 8 d prolonged culture, the photosynthesis and mean relative growth rate (RGR) of germlings were all markedly lowered, whereas the malondialdehyde (MDA) contents increased as the salinity desalted from 34 to 15. The salinity decrease from 34 to 25 had no significant effect on the RGR, but obviously influenced the morphology of the germlings. High salinity level (45) significantly depressed the RGR and photosynthesis of U. fasciata germlings, while it notably increased the MDA contents. The results showed that the salinity elevation had more detrimental effects on Ulva fasciata germlings than salinity decrease did. The germlings grown at the salinity seawater levels from 25 to 34, performed preferable photosynthetic acclimation both in temporary and prolonged culture. Broad salinity tolerance from 25 to 34 in U. fasciata germlings may have partly evolved as a response to regular diurnal tides.

Effects of high-salinity seawater acclimation on the levels of d-alanine in the muscle and hepatopancreas of kuruma prawn, Marsupenaeus japonicus

Changes in d- and l-alanine contents were determined in the muscle and hepatopancreas of kuruma prawn Marsupenaeus japonicus, during acclimation from seawater containing 100% salinity to artificial seawater containing 150% salinity. In the hepatopancreas, contents of both amino acids increased by approximately threefold. The activity of alanine racemase, which catalyzes the interconversion of d- and l-alanine, also increased in the high-salinity seawater. In addition, the expression of the gene encoding alanine racemase increased in the hepatopancreas with an increase in the alanine racemase activity. These data indicate that the biosynthesis of d- and l-alanine is controlled by the gene expression level of alanine racemase, and d-alanine in the hepatopancreas functions as a major osmolyte for isosmotic regulation. In contrast, the content of d-alanine and alanine racemase activity did not change in the muscle during hyper-osmotic acclimation. Therefore, we suggest that d-alanine, which exists in the several tissues of M. japonicus, is considered to be utilized in some different physiological phenomena in different tissues.

Effect of seawater salinity on pore-size distribution on a poly(styrene)-based HP20 resin and its adsorption of diarrhetic shellfish toxins

In the present study, okadaic acid (OA) and dinophysistoxin-1 (DTX1) were spiked into artificial seawater at low, medium and high estuarine salinities (9‰, 13.5‰ and 27‰). Passive samplers (HP20 resin) used for solid phase adsorption toxin tracking (SPATT) technology were exposed in these seawaters for 12-h periods. Adsorption curves well fitted a pseudo-secondary kinetics model. The highest initial sorption rates of both toxins occurred in the seawater of medium salinity, followed by seawater of low and high estuarine salinity. Pore volumes of micropores (<2nm) and small mesopores (2nm<diameter<10nm) of HP20 resin decreased after adsorption of toxins in seawater at high and low salinity but not in seawater at medium salinity, which demonstrated that the toxin molecules entered into micropores and mesopores (below 10nm in size) in seawaters of high and low salinity. More toxin or other matrix agglomerates were displayed on the surface of resin deployed in the seawater of medium salinity. Taking into consideration the pore-size distribution and surface images, it appears that intra-particle diffusion governs toxin adsorption in seawater at high salinity while film diffusion mainly controls the adsorption process in seawater at medium salinity. This is the first study to confirm that molecules of OA and DTX1 are able to enter into micropores (<2nm) and small mesopores (2–10nm) of HP20 resin in estuarine seawater with high salinity (∼27‰).

Concentration of enteric virus indicator from seawater using granular activated carbon

Fecal contamination of shellfish growing seawater with enteric viruses is often associated with human outbreaks of gastroenteritis. Male specific bacteriophage MS2 is correlated with those of enteric viruses in a wide range of water environments and has been used widely as a surrogate for pathogenic waterborne viruses. Since viruses in contaminated water are usually at low levels, the development of methods to concentrate viruses from water is crucial for detection purposes. In the present study, granular activated carbon was evaluated for concentration of MS2 from artificial seawater, and different parameters of the seawater were also compared. Recovery of MS2 from warm seawater (37°C) was found to be significantly greater than from cold seawater (4 and 20°C), and even greater than from fresh water (4, 20 and 37°C); the difference between seawater and fresh water became less profound when the temperatures of both were below 37°C. Although not of statistical significance, recovery of MS2 from low salinity seawater (10 and 20 parts per thousand, ppt) was greater than from high salinity seawater (30 and 40ppt). One gram of granular activated carbon was able to extract 6-log plaque forming units (PFU) of MS2 from 500ml seawater at 37°C. This study demonstrated that granular activated carbon can concentrate an enteric virus indicator from shellfish growing seawater effectively.

A review of hybrid desalination systems for co-production of power and water: analyses, methods, and considerations

The production of freshwater from seawater is a growing necessity throughout the world. In arid areas with high temperature and salinity seawater, thermal desalination and power plants (dual-purpose/cogeneration plants) are often employed for the production of power and water. In other areas, reverse osmosis is commonly employed. However, both technologies are inherently challenged with economic and performance issues. As a response to these issues, hybrid desalination, that is, employing both thermal and mechanical desalination methods, has been increasingly utilized over thermal desalination plants alone. In this article, an overview of thermal desalination, seawater reverse osmosis (SWRO), and co-generation of power and water is presented, specifically with regards to the motivation for utilizing hybrid plants, for example, process limitations and areas of potential improvement. In addition, a review of the considerations for design and economics of hybrid desalination plants is presented, for example, existing system configurations, thermoeconomic analyses, and improvements of seawater pretreatment are discussed. Finally, studies for the optimization of hybrid desalination systems are reviewed. Specifically, the use of objective functions, continuous optimization methods, and optimal hardware configurations are discussed with respect to the key considerations of hybrid desalination plants.

Technoeconomic analysis of once through long tube MSF process for high capacity desalination plants

This work presents a technoeconomic comparison between once through long tube (MSF-OT-LT) with atmospheric deaerator, and brine recycle cross tube (MSF-BR-CT) evaporators. The process design and cost analysis of 30 MIGD MSF-OT-LT evaporator is presented.The process calculations showed that for the same performance ratio, the heat transfer area of MSF-OT-LT is 34% lower than that of MSF-BR evaporator. This is due to the flashing range increase and higher heat transfer coefficient of MSF-OT-LT configuration. The pumping power of the MSF-OT-LT is 40% lower than that of MSF-BR-CT evaporator. This is due to lower friction loss in the tubes and due to remove brine recycle pump. A novel configuration of MSF-OT-LT is proposed in which the stages are arranged in a triple deck. The footprint decreases up to 57% in the large size project of 150 MIGD.For a large size project of 150 MIGD capacity, the unit water cost of the MSF-OT-LT configuration is 36% lower than that of the MSF-BR-CT. It can be concluded from this study that the MSF-OT-LT evaporator is a viable option for large scale capacity and a reliable technology for poor quality and high salinity sea water.

Sources of fluorescent dissolved organic matter in high salinity seawater (Bohai Bay, China)

Fluorescent dissolved organic matter (FDOM) identified in coastal waters within a large salinity range had been widely reported in previous studies, which stated that conservative mixing of terrestrially derived and river-transported FDOM by clear seawaters could account for the relatively low FDOM fluorescence signals in high salinity seawaters. This study aimed at testing the conservative mixing model in high salinity seawaters in a shallow bay (Bohai Bay, China) with low river flow in a dry season. The water showed high salinities varying in a narrow range (30.52 - 2.07), and salinity effects on fluorescence quantum yields therefore less likely introduced complications to fluorescence data analyses. By applying a parallel factor analysis to fluorescence excitation emission matrices of the water samples, we identified a tyrosine-like FDOM component, a tryptophan-like FDOM component, and two humic substances-like FDOM components. Based on a theoretical analysis, we found that dissolved organic carbon concentrations and suspended solid concentrations of the bulk-water samples as well as the maximum fluorescence signals of each identified FDOM component showed spatial distributions that could not be accounted for by the conservative mixing model. Marine autochthonous processes including microbial activities and FDOM releasing from resuspended sediment were likely to be invoked.

Geochemical characteristics and genetic model of dolomite reservoirs in the eastern margin of the Pre-Caspian Basin

The widespread Carboniferous KT-I dolomite in the eastern margin of the Pre-Caspian Basin is an important hydrocarbon reservoir. The dolomite lithology is dominated by crystalline dolomite. The δ18O values range from −6.71‰ to 2.45‰, and average 0.063‰, obviously larger than −2.5‰, indicating low-temperature dolomite of evaporation origin. Stable strontium isotope ratios (87Sr/86Sr) range from 0.70829 to 0.70875 and average 0.708365, very consistent with 87Sr/86Sr ratios in Carboniferous seawater. Chemical analysis of Ca and Mg elements shows that the dolomite has 9.1 mole% excess Ca or even higher before stabilization. The degree of order of dolomite is medium-slightly poor, varying in a range of 0.336–0.504 and averaging 0.417. It suggests that the dolomite formed under near-surface conditions. There are two models for the origin of the Carboniferous KT-I dolomite reservoir. These are 1) the evaporation concentration — weathering crust model and 2) the shoal facies — seepage reflux model. The former is mainly developed in restricted platforms — evaporate platforms of restricted marine deposition environments with a representation of dolomite associated with gypsum and mudstone. The latter mainly formed in platform edge shoals and intra-platform shoals and is controlled by dolomitization due to high salinity sea water influx from adjacent restricted sea or evaporate platform.

Behavioural adaptation to different salinities in the sandhopper Talitrus saltator (Crustacea: Amphipoda): Mediterranean vs Baltic populations

The sandhopper Talitrus saltator is common on sandy beaches at different latitudes. Therefore, behavioural variations allowing them to cope with a wide range of environmental variation are expected. To test the hypothesis that behavioural adaptations to natural environments are characterised by different salinities, we compared two behaviours (substrate choice and escape from immersion) of two T. saltator populations from a Mediterranean (high salinity) and a Baltic Sea (low salinity) sandy beach. T. saltator preferred to burrow in the high salinity substrate, irrespective of its beach of origin. Regarding orientation to escape from immersion, Baltic sandhoppers always oriented landwards, whereas Mediterranean sandhoppers showed a significant orientation landwards only when immersed in high salinity sea water. These behavioural traits matched the different environments, and this adaptation capability can be used as a model to analyse the response of a keystone species to environmental changes.

BOX MODEL AIR TAWAR, SALINITAS DAN ZAT HARA DI DELTA MAHAKAM KALIMANTAN TIMUR

Box Model of Freshwater, Salinity and Nutrient in the Delta Mahakam East Kalimantan. Research has been conducted in the southern part of the Mahakam Delta, East Kalimantan. Method of measuring temperature, salinity, light transmission and turbidity by using CTD model 603 SBE and current measurement and bathymetry by using ADCP model RDI. Measurement parameters on the nutrient chemistry are based of water samples taken using Nansen bottles from two depths. The purpose of this study to determine the mechanism of freshwater, salinity and nutrient transport from the land of the Mahakam River which interact with seawater by using box models. The results illustrate that the vertical distribution of salinity in the Mahakam Delta has obtained a high stratification, where the freshwater salinity 12.30 psu at the surface of a river flowing toward the sea, and seawater of high salinity 30.07 psu flowing in the direction river under the surface that are separated by a layer of mixture. Freshwater budget of the sea (VSurf) obtained for 0,0306 x 109 m3 day-1, and the sea water salinity budget is going into the bottom layer system (VDeep.SOcn-d) obtained for 20,727 x 109 psu day-1. While time dilution (τSyst) obtained for 0.245 day-1 or 5.87 hours. Nutrient budget in the surface layer obtained by the system is autotrophic while in layers near the bottom tend to be heterotrophic. Keywords: box model, freshwater, Mahakam Delta, nutrient, salinity

Cost effective way to harvest estuarine water: variable salinity desalination concept

Singapore, a small island city-state with some 700 km 2 in land area and a population of 4.5 million, is always looking for innovative ways to find new water sources to meet its growing need for water. Rain falling in the urban fringe catchments is not harvested; these areas experience bouts of heavy rain but dry up during the dry season and, as such, the conventional approach of constructing large dams for storage to support large water treatment plants is not economically viable. This paper explores the viability of a newly developed variable salinity water desalination treatment plant to harvest water from estuarine catchments. The plant is able to treat estuarine waters which vary gradually from low salinity river water into high salinity seawater. When the river water has high salinity or dries up, treatment is maintained with the plant operating in seawater desalination mode instead of remaining idle, thus affording high plant utilisation. The treated water is of high grade with energy consumption half that of seawater desalination plants. The average unit production and capital cost of such variable salinity desalination plants is significantly lower than that of seawater desalination plants.

Documentation of Yields of Laver Porphyra After Treating with Acidified Seawater and High Salinity Seawater to Suppress Red Rot Disease

Documentation of Yields of Laver Porphyra After Treating with Acidified Seawater and High Salinity Seawater to Suppress Red Rot Disease