Artificial Seawater Research Articles

Tribo-Corrosion Control with Molecules of Bio-Origin: Experimental Studies and Theoretical Insights

Tribo corrosion control of 6061 aluminum alloy was done by using naturally available Boswellia serrata (BWS) extract as green inhibitor. Studies were done in artificial sea water slurry containing 0.03% sand particles via a submerged jet impingement technique. Electrochemical studies were the majour techniques adopted for corrosion rate measurement in the absence and in the presence of inhibitor. Investigation was done at different flow rates and at different temperatures. Detailed surface study was done for sand particles before and after impingement using scanning electron microscope. Surface morphology of aluminum sample was done before and after the addition of inhibitor. For a given flowrate inhibition efficiency decreased with increase in temperature. This suggested the possibility of physical adsorption. Results were fitted into suitable adsorption isotherm. Mechanism of adsorption was supported and substantiated by quantum chemical calculations using Density Functional Theory (DFT). The best corrosion–erosion resistance was obtained at a concentration of 1000 ppm Boswellia serrata at 303 K under 4 L min−1. DFT studies supported the adsorption mechanism of the inhibitor on the surface of metal under tribological conditions. The outcome of this work will help in research that is focused on development on green inhibitors for corrosion inhibition under dynamic multi flow conditions.

Understanding the transition to viable but non-culturable state in Escherichia coli W3110: a comprehensive analysis of potential spectrochemical biomarkers

The viable but non-culturable (VBNC) state is considered a survival strategy employed by bacteria to endure stressful conditions, allowing them to stay alive. Bacteria in this state remain unnoticed in live cell counts as they cannot proliferate in standard culture media. VBNC cells pose a significant health risk because they retain their virulence and can revive when conditions normalize. Hence, it is crucial to develop fast, reliable, and cost-effective methods to detect bacteria in the VBNC state, particularly in the context of public health, food safety, and microbial control assessments. This research examined the biomolecular changes in Escherichia coli W3110 induced into the VBNC state in artificial seawater under three different stress conditions (temperature, metal, and antibiotic). Initially, confirmation of VBNC cells under various stresses was done using fluorescence microscopy and plate counts. Subsequently, lipid peroxidation was assessed through the TBARS assay, revealing a notable increase in peroxidation end-products in VBNC cells compared to controls. ATR-FTIR spectroscopy and chemomometrics were employed to analyze biomolecular changes, uncovering significant spectral differences in RNA, protein, and nucleic acid concentrations in VBNC cells compared to controls. Notably, RNA levels increased, while protein and nucleic acid amounts decreased. ROC analyses identified the 995 cm− 1 RNA band as a consistent marker across all studied stress conditions, suggesting its potential as a robust biomarker for detecting cells induced into the VBNC state under various stressors.

A MAX phase (Ti3AlC2) as a performance enhancer for poly(lactic acid) electrospun membranes in steam generation and solar desalination

Clean water and sanitation issues motivate researchers to develop water evaporators for freshwater generation. The composite membrane evaporator was electrospun herein based on poly(lactic acid) (PLA) and Ti3AlC2 MAX phase as a property enhancer. As a precursor for the MXenes synthesis, the MAX phase has never been explored with PLA for water evaporator potential. Alternative use of the MAX phase can reduce the production cost arising from chemical synthesis. This work explored the potential of the MAX phase as an additive to enhance PLA membrane performance for steam generation and desalination applications. Under the infrared irradiation (∼1.0 kW/m2), the mechanically-improved PLA/MAX phase membrane showed an enhanced water evaporation rate of 1.70 kg/m2 h (93.93 % efficiency), with an approximately 52 % rate increment relative to the PLA membrane. Based on the artificial seawater (3.5 % w/w), the membrane exhibited an evaporation rate of 1.60 kg/m2 h (87.57 % efficiency). The membrane showed self-floating ability at the air-water interface, excellent thermal stability over the entire operating temperatures, and reusability after repeated cycles. Moreover, the generated freshwater contained exceptionally low cations concentrations, as low as those in potable water. The developed composite membrane also had proved its potential for solar desalination in the water generation field.

Inorganic salt starvation improves the polysaccharide production and CO2 fixation by Porphyridium purpureum.

The microalgae industry shows a promising future in the production of high-value products such as pigments, phycoerythrin, polyunsaturated fatty acids, and polysaccharides. It was found that polysaccharides have high biomedical value (such as antiviral, antibacterial, antitumor, antioxidative) and industrial application prospects (such as antioxidants). This study aimed to improve the polysaccharides accumulation of Porphyridium purpureum CoE1, which was effectuated by inorganic salt starvation strategy whilst supplying rich carbon dioxide. At a culturing temperature of 25°C, the highest polysaccharide content (2.89g/L) was achieved in 50% artificial seawater on the 12th day. This accounted for approximately 37.29% of the dry biomass, signifying a 25.3% increase in polysaccharide production compared to the culture in 100% artificial seawater. Subsequently, separation, purification and characterization of polysaccharides produced were conducted. Furthermore, the assessment of CO2 fixation capacity during the cultivation of P. purpureum CoE1 was conducted in a 10L photobioreactor. This indicated that the strain exhibited an excellent CO2 fixation capacity of 1.66g CO2/g biomass/d. This study proposed an efficient and feasible approach that not only increasing the yield of polysaccharides by P. purpureum CoE1, but also fixing CO2 with a high rate, which showed great potential in the microalgae industry and Bio-Energy with Carbon Capture and Storage.

Surface roughness influence on extracellular electron microbiologically influenced corrosion of C1018 carbon steel by Desulfovibrio ferrophilus IS5 biofilm

Carbon steel microbiologically influenced corrosion (MIC) by sulfate reducing bacteria (SRB) is known to occur via extracellular electron transfer (EET). A higher biofilm sessile cell count leads to more electrons being harvested for sulfate reduction by SRB in energy production. Metal surface roughness can impact the severity of MIC by SRB because of varied biofilm attachment. C1018 carbon steel coupons (1.2 cm2 top working surface) polished to 36 grit (4.06 μm roughness which is relatively rough) and 600 grit (0.13 μm) were incubated in enriched artificial seawater inoculated with highly corrosive Desulfovibrio ferrophilus IS5 at 28 ℃ for 7 d and 30 d. It was found that after 7 d of SRB incubation, 36 grit coupons had a 11% higher sessile cell count at (2.0 ± 0.17) × 108 cells/cm2, 52% higher weight loss at 22.4 ± 5.9 mg/cm2 (1.48 ± 0.39 mm/a uniform corrosion rate), and 18% higher maximum pit depth at 53 μm compared with 600 grit coupons. However, after 30 d, the differences diminished. Electrochemical tests with transient information supported the weight loss data trends. This work suggests that a rougher surface facilitates initial biofilm establishment but provides no long-term advantage for increased biofilm growth.

Corrosion Behavior of Al2O3-40TiO2 Coating Deposited on 20MnNiMo Steel via Atmospheric Plasma Spraying in Hydrogen Sulfide Seawater Stress Environments

In this study, an Al2O3-40TiO2 coating was deposited on 20MnNiMo steel via atmospheric plasma spraying. The corrosion behavior of the coating was investigated in both artificial seawater and a simulated environment with hydrogen sulfide and high pressure. Additionally, ion dissolution experiments were conducted to evaluate the coating’s bio-friendliness. In artificial seawater, the corrosion rate (based on the corrosion current) of the Al2O3-40TiO2 coating initially decreased before increasing. It was speculated that the blocking of corrosion products in the defect channels was helpful in delaying the progress of corrosion in the early stage. The coating had a corrosion current on the order of 10−6 A/cm2 in artificial seawater, suggesting good protection in conventional seawater environments. In the simulated environment, the corrosion rate (based on the weight loss) of the Al2O3-40TiO2 coating showed a continuously declining trend. It was deduced that, unlike corrosion products in artificial seawater, the corrosion products in the simulated environment (e.g., metal sulfide) might be more chemically stable, leading to a longer blocking effect. Therefore, a minimal corrosion rate of 0.0030 mm/a was obtained after the coating was immersed for 30 days. The amount of dissolved coated elements was negligible and there were only small amounts of dissolved non-coated elements such as Ni and Mo. The developed coating can be considered to be highly biofriendly if the non-coated area of the specimen is well sealed.

An investigation into the effect of UV irradiation and biofilm colonization on adsorption and desorption behavior of polyurethane (PU) microplastics for bisphenol A (BPA)

Recent studies have demonstrated that microplastics (MPs) can act as a transport vector for pollutants in the environment. However, most studies have focused on carbon-carbon backbone polymers, with little known about heteroatom backbone polymers. In this study, polyurethane (PU) MPs were modified by UV irradiation and microorganism colonization to assess the different aging treatments on the interaction behavior (adsorption/desorption) between PU MPs and bisphenol A (BPA). The results of the adsorption kinetics experiment illustrated that the adsorption process of BPA could be described well by a pseudo-second order kinetic equation on both fresh and aged PU MPs. Although fresh PU MPs revealed the highest saturated adsorption capacity, at low BPA exposure concentrations (≤ 100 μg/L) the adsorption capacities for UV aged and biofilm colonized PU MPs were very similar to fresh MPs or even slightly higher than for fresh MPs, the main adsorption mechanisms including H-bonding interactions and π–π interactions. Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) investigations suggested obvious physicochemical property changes (e.g., generation of new functional groups, erosion, etc.) after UV irradiation and biofilm colonization. This study also showed that different exposure environments (ultrapure water, artificial seawater, simulated gastric fluid) could affect BPA adsorption/desorption via hydrophobic and electrostatic interaction on PU surfaces. These results further clarify the adsorption mechanisms of BPA on PU MPs that have undergone different aging treatments, and provides a theoretical basis for the assessment of environmental behavior and exposure risks when PU MPs and BPA coexist.

Fabrication of porous biochar supported Bi2MoO6 photocatalyst for efficient degradation of ciprofloxacin in seawater under visible light irradiation: Mechanistic investigation and intermediates analysis

Efficient separation of photocarriers is a critical approach for advancing high-performance photocatalyst systems to effectively remove environmental contaminants. In this investigation, a hydrothermal technique was employed to synthesize composites of Bi2MoO6 and porous biochar derived from banana peels (BPB). The samples underwent various characterization methods to assess their composition, morphology, and photoelectrochemical properties. The BPB/Bi2MoO6 composite exhibited a synergistic adsorption and photocatalytic impact in eliminating the antibiotic ciprofloxacin (CIP) from pure water and seawater. The optimized BPB/Bi2MoO6 sample displayed a significant degradation efficiency of 98.7 % for CIP after 90 min of visible-light exposure in pure water. In artificial seawater, the degradation efficiency for CIP remained high at 93.6 %, which was 12.2 times greater than that of pure Bi2MoO6. The study also explored the impact of various factors such as catalyst dosage, solution pH, and pollutant concentration on the photocatalytic performance of BPB/Bi2MoO6. Moreover, the catalyst exhibited enhanced efficiency in the adsorption-photocatalytic degradation of CIP within a continuous flow reaction system. The enhanced photocatalytic performance was attributed to the composite's exceptional adsorption capacity, enhanced response to visible light, and efficient separation of photoinduced electron-hole pairs. Furthermore, the BPB/Bi2MoO6 photocatalyst displayed good stability and recyclability over five consecutive photodegradation cycles. Radical trapping and electron spin resonance (ESR) experiments verified that the degradation of CIP was mainly driven by •OH and h+ radicals. A thorough investigation employing density functional theory (DFT), radical trapping and ESR tests, and liquid chromatography mass spectrometry (LC-MS) was conducted to elucidate the degradation mechanism and pathways. Furthermore, toxicity assessment software was utilized to illustrate the progressive reduction in toxicity of the intermediate products. In conclusion, this study provides valuable insights into the role of biochar in enhancing the photocatalytic degradation of pollutants and offers guidance for the future development of environmentally friendly photocatalysts.

Environmental Homeopathy: Homeopathic Potencies Regulate the Toxicity and Growth of Raphidiopsis raciborskii (cyanobacteria) and can be Tracked Physico-Chemically. Part 1: Biological Results.

Cyanobacteria are microorganisms found in many parts of the world and several genera, such as Raphidiopsis raciborskii, are producers of cyanotoxins. Homeopathic potencies have been found to modulate toxicity in different biological models, and the present study endeavors to discover whether this might also be the case with cyanobacteria. Our objective was to investigate the possible effects of homeopathic potencies on the resilience of Artemia franciscana (brine shrimp) embryos to saxitoxin (STX; cyanotoxin) and on controlling the growth of R. raciborskii in vitro. A. franciscana cysts were cultivated in seawater in 96-well plates to evaluate the hatching rate and vitality, plus the gene expression of heat shock proteins (HSPs), after being challenged with R. raciborskii extract containing 2.5 µg/L of STX and treated with different homeopathic potencies. Untreated wells were used as controls ("base-line"). Potencies were chosen from a screening process based on seven selected homeopathic preparations according to the similitude of STX symptoms (Sulphur, Zincum metallicum, Nitric acidum, Plumbum metallicum, Mercurius solubilis, Phosphoric acidum, Isotherapic from R. raciborskii extract; all at 6cH, 30cH and 200cH). Cultures of R. raciborskii maintained in an artificial seawater medium were equally treated with screened homeopathic potencies selected from the same list but specifically for their growth control as a function of time. A 15% lower rate of hatching of A. franciscana cysts was observed after treatment with Nitric acidum 6cH in comparison with baseline (p = 0.05). A complete toxicity reversal was seen after treatment with Isotherapic 200cH, with a 23-fold increase of Hsp 26 gene expression (p = 0.023) and a 24-fold increase of p26 gene expression (p ≤ 0.001) in relation to baseline. Nitric acidum 200cH and Mercurius solubilis 30cH limited the exponential growth of cyanobacteria up to 95% and 85% respectively (p ≤ 0.003) in relation to baseline. Succussed water presented only a transitory 50% inhibition effect. Isotherapic 200cH improved A. franciscana bioresilience to STX; Nitric acidum 200cH and Mercurius solubilis 30cH showed the optimal performance on limiting R. raciborskii growth. The results point to the potential of homeopathic potencies to mitigate environmental problems related to water quality.

Environmental Homeopathy: Homeopathic Potencies Regulate the Growth and Toxicity of Raphidiopsis raciborskii (cyanobacteria) and Can be Tracked Physico-Chemically. Part 2: Physico-chemical Results.

The control of cyanobacterial toxicity and growth by homeopathic potencies was described in Part 1 of this two-part report. Here, a parallel approach characterized the physico-chemical features of the potencies used and the liquid media treated with them, correlating these results with their respective biological effects. Our objective was to establish if physico-chemical parameters can track homeopathic potencies in seawater or artificial seawater medium (ASM)-1 and to discover whether these parameters correlate with previously described biological effects. Artemia franciscana (brine shrimp) cysts were cultivated in seawater challenged with Raphidiopsis raciborskii extract and treated with different homeopathic potencies chosen from a screening process. Cultures of R. raciborskii maintained in ASM-1 were also treated with previously screened homeopathic potencies, and their growth was monitored as a function of time. The physico-chemical properties of the treated media (seawater or ASM-1) were evaluated by their interaction with solvatochromic dyes and changes in pH, conductivity and temperature. Coumarin 7 was found to be a marker for Nitric acidum 6cH and Isotherapic (R. raciborskii extract) 200cH in seawater (analysis of variance [ANOVA], p = 0.0015). Nile red was found to be a marker for Nitric acidum 200cH and Mercurius solubilis 30cH in ASM-1 (ANOVA, p ≤ 0.001). An increase in pH of ASM-1 and endothermic effects were observed after these treatments (two-way ANOVA, p = 0.0001). Seawater and ASM-1 to which potencies had been added were also subjected to a constant unidirectional 2,400 Gauss static magnetic field and found to have enhanced effects on the solvatochromic dyes tested. Homeopathic potencies were specifically traceable in aqueous media using solvatochromic dyes, especially when the samples were subjected to a magnetic field. Results from monitoring other physical parameters, such as pH and temperature, were less specific in relation to potency tracking. However, potency-induced endothermic effects might provide valuable thermodynamic data relating to the nature of potencies.

Enhanced antifouling performance with a synergistic effect of self-renewal antifouling and contact bacteriostasis via the ionic exchange

It is extremely difficult for traditional coatings for antifouling constructed around a single antifouling strategy to adapting to the demands of complex marine environment. Herein, a poly-ionic liquid-based germicidal polyacrylate-3 coating (AFC-3) was prepared via free radical photo-copolymerization using isooctyl acrylate (2-EHA), butyl acrylate (BA) and ionic liquid monomer (IL-PF6) as monomers. Besides the contact bacteriostasis mechanisms, the introduction of IL-PF6 achieved the switch between self-renewal and hydrophilic surface by the exchange of PF6− and Cl− in artificial seawater. Regarding E. coli and S. aureus, the AFC-3 coating showed anti-bacterial efficiency of 100 % and 99.96 %, respectively. Moreover, with the continuous ionic exchange between PF6− and Cl−, the angle towards the water contact (WAC) of the coating became 11.356 °C, contributing to the enhancement of anti-protein property on the surface of the coating. The AFC-3 coating thus exhibited significantly effective antifouling performances, and is a highly promising coating for a broader range of marine anti-fouling and biomedical materials. Besides, the transmittance of the coating was above 92 % between 400 and 800 cm−1, conferring it great potentials for applications on the surface of optical devices like underwater cameras.

Reactive gliosis in adult zebrafish telencephalon following daily nanoplastic consumption

Background: Polystyrene nanoplastics are one of the most pervasive plastic contaminates and have been shown to infiltrate multiple mediums that are ingested by humans including air, food and water. Additionally, polystyrene nanoparticles have been shown to cross the blood brain barrier (BBB), the brain's first defense against pathogens and toxins. Following insult, the neuronal immune network enters a pro-inflammatory state referred to as reactive gliosis. Reactive gliosis is characterized by the recruitment of microglia and astroglia, the resident immune cells of the central nervous system (CNS), into a pro-inflammatory state that leads to the release of cytokines and the creation of a glial scar. This cascade of morphological and chemical changes in the CNS following prolonged insult can induce significant damage to the brain. Experiments in rodent models and cell culture indicate that exposure to plastic nanoparticles can induce inflammatory processes in the brain. This has been relatively underexplored in the zebrafish model system. In the current study we investigate the hypothesis that daily exposure to nanoplastics via the food chain can induce a chronic inflammatory state in the brain that may lead to permanent brain damage. The purpose of the current study is to investigate reactive gliosis in the telencephalon of adult zebrafish following the consumption of polystyrene-contaminated food. Methods: One thousand brine shrimp ( Artemia) per zebrafish were collected and incubated in artificial sea water (ASW) containing 44 nanometer (nm) fluorescent polystyrene (nPS) at a concentration of 0.15 milligrams (mg) nPS/50 milliliters (mL) ASW for 24 hours. Zebrafish were fed polystyrene-enriched brine shrimp once per day for fourteen consecutive days. On day fifteen, the telencephalon was removed and homogenized for western blot analysis. Reactive microglia were measured using the monoclonal 4C4 antibody which has been found to label reactive microglia. Reactive astrogliosis was quantified by measuring glial fibrillary acidic protein (GFAP), a marker for reactive astrocytes. Results: Confocal fluorescent imaging and spectrophotometry showed that Artemia were enriched with red-fluorescently tagged polystyrene nanoplastics. Additionally, the quantity of nanoplastic within one thousand shrimp was estimated to be 5 +/- 1.9 micrograms. There was an observed increase in 4C4 normalized to actin. Increases in GFAP were also detected. These data indicate that reactive gliosis by microglia and astroglia was enhanced in the zebrafish telencephalon after consuming polystyrene-contaminated food for fourteen consecutive days. Funding is supported by the Georgia Southern Department of Biology and Mercer University College of Medicine. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Functional modification of TC4 by Cu-containing titanium dioxide films

To improve the biological fouling and corrosion resistance of Ti6Al4V (TC4) in marine environments, copper-containing titanium dioxide (TiO2(Cu)) films were prepared by magnetron sputtering TiO2(Cu) powder targets. The morphologies of the films showed that they became rough and coarse from 1.6 nm of the TiO2 film to approximately 9 nm of the TiO2(Cu) films, which might be owing to the increase in the deposition rates from 1.33 to 2.08 nm/min. No diffraction orientations of the TiO2 and Cu phases were found compared to those of the TiO2(Cu) powder. Ti, O, and Cu were detected using X-ray photoelectron spectroscopy to confirm the composition of the films. The ratio of Cu2+ increased as the Cu content of the films increased, whereas that of Cu/Cu + scarcely changed. The TiO2 and TiO2(Cu) films exhibited photocatalytic effects and their photocatalytic intensities decreased as the Cu content increased. Hydrophobicity was enhanced by the addition of Cu to the film. The antibiological fouling effect of the TiO2(Cu) films remained unchanged as the Cu/Ti ratio varied. Compared with those of TC4, the corrosion current densities of the TiO2(Cu) films decreased by one order of magnitude and the corrosion potentials increased by 350 mV in artificial seawater, indicating that the corrosion resistance of TiO2(Cu)/TC4 was improved. Importantly, Cu was in abundance in the films for both antibiological and corrosion resistance functions owing to the saturated ratio of Cu/Cu+ irrespective of the Cu/Ti ratio in the films.

Electrochemical corrosion and tribocorrosion behavior of CrN and CrAlN coatings in artificial seawater

AbstractThis study investigated the corrosion and tribocorrosion behavior of CrN and CrAlN coatings deposited on steel through direct current magnetron sputtering. Additionally, the effects of Al addition on the microstructure, corrosion inhibition, and tribocorrosion behavior of CrN coatings were evaluated. Compared with the CrN coating, the CrAlN coating exhibited a denser columnar crystal structure and a higher hardness of 23.8 GPa. The CrAlN coating reacted with water to form Al2O3 and Cr2O3 films, which enhanced its corrosion resistance. Moreover, the addition of Al enhanced the wear resistance of the CrN coating and reduced the material loss due to corrosion, wear, and their synergistic effects. The CrAlN coating exhibited a low corrosion current density of 1.14 × 10−8 A/cm2, indicating a 92% reduction compared with the CrN coating. Furthermore, under either open circuit potential or anodic accelerated tribocorrosion conditions, the CrAlN coating featured significantly lower total material loss and synergistic material loss than the CrN coating, demonstrating higher corrosion and tribocorrosion protection.

All-natural 2D nanofluidics as highly-efficient osmotic energy generators

Two-dimensional nanofluidics based on naturally abundant clay are good candidates for harvesting osmotic energy between the sea and river from the perspective of commercialization and environmental sustainability. However, clay-based nanofluidics outputting long-term considerable osmotic power remains extremely challenging to achieve due to the lack of surface charge and mechanical strength. Here, a two-dimensional all-natural nanofluidic (2D-NNF) is developed as a robust and highly efficient osmotic energy generator based on an interlocking configuration of stacked montmorillonite nanosheets (from natural clay) and their intercalated cellulose nanofibers (from natural wood). The generated nano-confined interlamellar channels with abundant surface and space negative charges facilitate selective and fast hopping transport of cations in the 2D-NNF. This contributes to an osmotic power output of ~8.61 W m−2 by mixing artificial seawater and river water, higher than other reported state-of-the-art 2D nanofluidics. According to detailed life cycle assessments (LCA), the 2D-NNF demonstrates great advantages in resource consumption (1/14), greenhouse gas emissions (1/9), and production costs (1/13) compared with the mainstream 2D nanofluidics, promising good sustainability for large-scale and highly-efficient osmotic power generation.

Effects of salinity stress on physiological behavior, respiratory metabolism, and intestinal transcriptome of juvenile Stichopus monotuberculatus

This study investigated the impacts of salinity stress on the physiological behavior, respiratory metabolism, and transcriptome of artificially cultured juvenile Stichopus monotuberculatus (S. monotuberculatus) (with a body weight of 3.23 ± 0.60 g). S. monotuberculatus individuals cultured in artificial seawater were transferred to artificial seawater with salinities of 20‰, 30‰, and 40‰ for salinity stress treatment. The physiological behavior of S. monotuberculatus was observed, and their ammonia discharge rates, oxygen consumption rates, and oxygen/nitrogen (O/N) ratios were measured. After 24 h of stress, the intestines of S. monotuberculatus were collected for transcriptome sequencing. The results showed that both hyper-salinity and hypo-salinity stresses significantly affected the physiological status of S. monotuberculatus. The oxygen consumption and ammonia discharge rates of the hyper-salinity group (40‰) and hypo-salinity (20‰) group were remarkably higher than those of the control group (P<0.05), and the O/N ratios of the two groups were significantly lower than those of the control group (P<0.05). Sequencing identified a total of 3840 differentially expressed genes (DEGs) from the salinity-stress groups and the control group. GO analysis revealed that DEGs were mainly enriched in biological processes, cellular components, and molecular functional categories, with the highest enrichment observed in cellular processes, metabolic processes, membranes, binding, and catalytic activities. KEGG analysis showed that the DEGs of hyper-salinity and hypo-salinity groups were enriched in different secondary pathways, with the expressions of related genes significantly upregulated, indicating that S. monotuberculatus may adapt to hyper-salinity and hypo-salinity environments through various regulatory mechanisms. The results verify that salinity stress significantly affects the physiological behavior and respiratory metabolism of S. monotuberculatus. S. monotuberculatus respond to hyper-salinity and hypo-salinity stresses by increasing protein consumption and adopting different adaptation mechanisms. Furthermore, S. monotuberculatus exhibits stronger tolerance to hypo-salinity environments compared to hyper-salinity ones.

Cocktail effects of tire wear particles leachates on diverse biological models: A multilevel analysis

Tire wear particles (TWP) stand out as a major contributor to microplastic pollution, yet their environmental impact remains inadequately understood. This study delves into the cocktail effects of TWP leachates, employing molecular, cellular, and organismal assessments on diverse biological models. Extracted in artificial seawater and analyzed for metals and organic compounds, TWP leachates revealed the presence of polyaromatic hydrocarbons and 4-tert-octylphenol. Exposure to TWP leachates (1.5 to 1000 mg peq L−1) inhibited algae growth and induced zebrafish embryotoxicity, pigment alterations, and behavioral changes. Cell painting uncovered pro-apoptotic changes, while mechanism-specific gene-reporter assays highlighted endocrine-disrupting potential, particularly antiandrogenic effects. Although heavy metals like zinc have been suggested as major players in TWP leachate toxicity, this study emphasizes water-leachable organic compounds as the primary causative agents of observed acute toxicity. The findings underscore the need to reduce TWP pollution in aquatic systems and enhance regulations governing highly toxic tire additives.

Thin Coatings of Polymer of Intrinsic Microporosity (PIM‐1) Enhance Nickel Electrodeposition and Nickel‐Catalyzed Hydrogen Evolution

AbstractNickel nanoparticle electrodeposition is studied on flat glassy carbon (GC) or on nitrogen‐doped reduced graphene oxide (rGO‐N) substrates. The effects of a very thin (nominally 16 nm) layer polymer of intrinsic microporosity (PIM‐1) are investigated (i) on enhancing nickel nanoparticle nucleation and growth during electrodeposition and (ii) on enhancing hydrogen evolution electrocatalysis. Beneficial effects are tentatively assigned to PIM‐1 suppressing blocking effects from interfacial hydrogen bubble formation. Exploratory data suggest that in aqueous 0.5 M NaCl solution (artificial seawater) nickel nanoparticles grown into a thin film of PIM‐1 could be a viable electrocatalyst with an onset of hydrogen evolution only slightly negative compared to that observed for platinum nanoparticles.

Study on seawater corrosion resistance of calcium sulfoaluminate cement-based novel grouting materials

Grouting materials play a critical role in anchoring structures of cross-sea tunnels by safeguarding the anchors against seawater corrosion and enhancing durability. In this paper, a novel grouting material comprising ferrite-rich sulfoaluminate cement (FCSA), ordinary Portland cement (OPC), anhydrite and limestone were prepared. Accelerated corrosion immersion tests were conducted to assess the corrosion resistance of the grouting material using artificial seawater solutions with varying salt concentrations. Pull-out tests were performed to verify the material's performance, while potentiometric titration and X-ray diffraction (XRD) analysis were employed to analyze free chloride ion concentration (Cf) and corrosion products at the anchorage interface. Results indicate that after 1.5 years of corrosion in seawater with different salt concentrations, the bond strength stabilized at 1.05 MPa. No rust was observed on the anchor surfaces and the Cf exhibited a linear increase with salt concentration. The content of Friedel's salt increases with salt concentration, demonstrating adequate chloride ion binding capacity. The test results validate the exceptional seawater corrosion resistance and long-term stability of the novel grouting material.

Establishment of Effective Callus Induction in the Economically Important Brown Seaweed Ecklonia cava

The edible brown seaweed, Ecklonia cava, is highly valued for its bioactive compounds, and is widely used in food supplements and functional foods. The increasing demand for this seaweed in the food industry emphasizes the necessity for sustainable cultivation practices. This study focused on inducing callus in the meristem and stipe of E. cava using different culture media: Provasoli’s enriched seawater medium (PESI), enriched artificial seawater medium (ESAW), artificial enriched seawater medium (ASP2), or Von Stosch’s enriched seawater medium (VS). Various abiotic stress factors (photoperiod, agar concentration, and temperature), growth regulators, carbon sources, polyamines, and plasma treatments were explored for their impact on callus induction. Both stipe and meristem explants developed callus within three to six weeks across all media except ASP2. Callus development was favored at temperatures between 8 to 13 °C and in the absence of light. Stipe explants showed a higher callus induction rate (up to 65.59 ± 6.24%) compared to meristem (up to 57.53 ± 8.32%). Meristem explants showed optimal callus induction in PESI medium with a low concentration of indole-3-acetic acid (IAA; 40.93 ± 8.65%). However, higher concentrations of IAA and 1-naphthaleneacetic acid (NAA) reduced meristem callus induction. Stipe showed high induced-callus (up to 50.37 ± 5.17%) in PESI medium with low concentrations of IAA, NAA, and 6-benzylaminopurine (BAP). Both stipe and meristem explants induced largest callus at 2% sucrose, but higher carbon source concentrations reduced callus induction. Spermine (Spm) at 1 µM resulted in high induced calluses; however, increasing Spm concentrations decreased callus induction. This tissue culture technique not only supports mass cultivation of E. cava, but also holds potential for extending to other seaweed species, contributing to the sustainability of seaweed stocks for the food industry.