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A significant proportion of marine calcium carbonate sediments are comprised of metastable minerals that are susceptible to diagenetic alterations during burial. These reactions can reset the geochemical signature of sediments and pore fluids and influence elemental cycling in the ocean. However, the timing and mechanisms by which these reactions take place are poorly constrained. This study uses cores drilled on the slope of the Great Bahama Bank to provide quantitative constraints on important diagenetic reactions; namely respiration-driven dissolution, authigenic carbonate mineral formation, and conversion of aragonite to low Mg calcite (LMC). We perform detailed mineralogical characterization using newly acquired, high resolution X-ray diffraction (XRD) data and over 1000 reanalyzed XRD scans, characterize sediments texturally and elementally using electron microprobe data, calculate pore fluid saturation state with respect to aragonite using a Pitzer ion interaction approach, and use pore fluid chemistry and experimental distribution coefficients to predict authigenic carbonate compositions. These data suggest that aerobic organic matter oxidation, enabled by the advection of oxygenated seawater throughout the upper ∼ 30 m interval of sediment, causes undersaturation and thus dissolution of biogenic high Mg calcite (HMC) and aragonite. Deeper, anaerobic organic matter oxidation takes over and causes supersaturation, promoting authigenic precipitation in the form of HMC, which in turn decreases pore fluid Mg/Ca and promotes aragonite conversion to LMC. One novel aspect of this study is the identification of three types of calcites using the newly acquired XRD and electron microprobe data. Based on their unique crystallographic characteristics and chemical compositions, these types of calcites are interpreted to represent pelagic biogenic LMC, bank-derived biogenic HMC, and authigenic HMC precipitated from pore fluids. Notably, the composition of the authigenic calcite matches that predicted to precipitate from pore fluids using an empirical Mg partition coefficient in calcite. Calcites that form authigenically and from aragonite via replacement are suggested to recrystallize with burial as evidenced by the decrease in Mg content and micro-strain. This process-based geochemical framework assigns diagenetic processes to a specific depth window within the sediment column and paves the way for a mechanistic understanding of carbonate diagenesis, one that is rooted in thermodynamic and kinetic bases. [ABSTRACT FROM AUTHOR]

Featured Application: The potential applications of this work include the reconstruction of artificial bacterial consortia that are able to resist and/or reduce chromium and are robust over time for a bioremediation application at the Quimica Central site (Mexico). Industrial residues with high concentrations of hexavalent chromium [Cr(VI)], characterized by an alkaline pH (between 9 and 13) and high salinity (around 100 psu), were used as a source for extremophilic chromium-resistant and -reducing microorganisms. An investigation of biodiversity through MiSeq showed the presence of 20 bacterial classes, with Bacilli (47%), Negativicutes (15%), Bacteriodia (8%), Gammaproteobacteria (7%) and Clostridia (5%) being the most abundant. The bioprospection allowed the cultivation of 87 heterotrophic bacterial colonies and 17 bacterial isolates at the end of the isolation, and screening procedures were obtained. The isolates were related to Cellulosimicrobium aquatile, C. funkei, Acinetobacter radioresistens, Staphylococcus equorum, S. epidermis, Brachybacterium paraconglometratum, Glutamicibacter creatinolyticus, Pseudomonas songnenensis, Microbacterium algeriense and Pantoea eucalypti, most of them being resistant to Cr(VI). Resistances of up to 400 m g. L − 1 of chromate were obtained for four related strains (QReMLB55A, QRePRA55, QReMLB33A and QReMLB44C). The C. aquatile strain QReMLB55A and the P. songnenensis strain QReMLB33A were exposed to K 2 C r 2 O 7 (200 m g. L − 1 ) under optimal conditions, diminishing 94% and 24% of the Cr(VI) in 6 days, respectively. These strains exhibited a high potential for chromium remediation biotechnologies. [ABSTRACT FROM AUTHOR]

Key message: Compared with NaCl, NaHCO3 caused more serious oxidative damage and photosynthesis inhibition in safflower by down-regulating the expression of related genes. Salt-alkali stress is one of the important factors that limit plant growth. NaCl and sodium bicarbonate (NaHCO3) are neutral and alkaline salts, respectively. This study investigated the physiological characteristics and molecular responses of safflower (Carthamus tinctorius L.) leaves treated with 200 mmol L−1 of NaCl or NaHCO3. The plants treated with NaCl treatment were less effective at inhibiting the growth of safflower, but increased the content of malondialdehyde (MDA) in leaves. Meanwhile, safflower alleviated stress damage by increasing proline (Pro), soluble protein (SP), and soluble sugar (SS). Both fresh weight and dry weight of safflower was severely decreased when it was subjected to NaHCO3 stress, and there was a significant increase in the permeability of cell membranes and the contents of osmotic regulatory substances. An enrichment analysis of the differentially expressed genes (DEGs) using Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes identified significant enrichment of photosynthesis and pathways related to oxidative stress. Furthermore, a weighted gene co-expression network analysis (WGCNA) showed that the darkgreen module had the highest correlation with photosynthesis and oxidative stress traits. Large numbers of transcription factors, primarily from the MYB, GRAS, WRKY, and C2H2 families, were predicted from the genes within the darkgreen module. An analysis of physiological indicators and DEGs, it was found that under saline-alkali stress, genes related to chlorophyll synthesis enzymes were downregulated, while those related to degradation were upregulated, resulting in inhibited chlorophyll biosynthesis and decreased chlorophyll content. Additionally, NaCl and NaHCO3 stress downregulated the expression of genes related to the Calvin cycle, photosynthetic antenna proteins, and the activity of photosynthetic reaction centers to varying degrees, hindering the photosynthetic electron transfer process, suppressing photosynthesis, with NaHCO3 stress causing more pronounced adverse effects. In terms of oxidative stress, the level of reactive oxygen species (ROS) did not change significantly under the NaCl treatment, but the contents of hydrogen peroxide and the rate of production of superoxide anions increased significantly under NaHCO3 stress. In addition, treatment with NaCl upregulated the levels of expression of the key genes for superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), the ascorbate-glutathione cycle, and the thioredoxin-peroxiredoxin pathway, and increased the activity of these enzymes, thus, reducing oxidative damage. Similarly, NaHCO3 stress increased the activities of SOD, CAT, and POD and the content of ascorbic acid and initiated the glutathione-S-transferase pathway to remove excess ROS but suppressed the regeneration of glutathione and the activity of peroxiredoxin. Overall, both neutral and alkaline salts inhibited the photosynthetic process of safflower, although alkaline salt caused a higher level of stress than neutral salt. Safflower alleviated the oxidative damage induced by stress by regulating its antioxidant system. [ABSTRACT FROM AUTHOR]

Rhizomania is one of the most destructive and damaging sugar beet diseases that has spread in different regions of Iran. In order to evaluate the genotypic, environmental, and genotype by environmental variability of sugar beet genotypes under rhizomania infection, variance components were estimated from the trial series in 7 years. Required data, such as yield and quality parameters, were collected from value for cultivation and use trials. Results of analysis of variance showed that the environment was the source that explained most of the variability, except for amino‐N and alkalinity. Quality traits were also influenced by the environment × cultivar interaction, so that 4.8% (white sugar content) to 46.1% (alkalinity) variance was observed. In contrast, genetic variation was much lower, between 1.2% (potassium) and 27.4% (amino‐N). A strong and negative correlation was found between root yield, sugar yield, and white sugar content with the disease index, which obviously illustrates the negative impact of the rhizomania on root weight and as a consequence on the dependent traits. The cluster analysis of the cultivars based on the quantitative and qualitative traits and the disease index showed that the range of variation in traits, such as the disease index, varied from 6.25 for the susceptible cultivar to 1.25 for the resistant one. This indicates the existence of sufficient genetic diversity among cultivars in terms of this trait. High impurity accumulation was observed in Shiraz region compared with Mashhad. In conclusion, it is observed that rhizomania has a significant effect on the impurity concentration in the root, especially sodium, potassium, and amino‐N. This is very important in the sugar industry because sugar extraction depends on the concentration of these impurities, in addition to the sugar content of each cultivar. [ABSTRACT FROM AUTHOR]

Diatoms are key components of freshwater ecosystems and are regularly used for paleolimnological reconstructions, in which defining species optima and tolerances is fundamental for interpreting assemblage shifts in a sediment record. Here, we examined responses of diatoms across three major environmental gradients—dissolved inorganic carbon (range: 0.1–230.5 mg · L−1), total phosphorus (range: 3–326 μg · L−1), and maximum lake depth (range: 0.9–55.0 m)—taken from 158 lakes from across Canada. The lakes were sampled as part of the LakePulse Network, which conducted a standardized sampling of lakes spanning 12 Canadian ecozones. Hierarchical logistic regression was used to model the species responses of 37 common taxa, and species optima and tolerances were calculated with weighted average modeling. The most common response detected was the symmetrical unimodal model, suggesting we likely captured the full environmental ranges for many species, although skewed unimodal responses were also common. Indicator species analyses identified taxa with high predictive values and fidelities to particular ecozones, with high‐nutrient‐adapted taxa such as Stephanodiscus spp. and Cyclotella meneghiniana characteristic of the agriculturally productive Prairie region. The Prairies stood out in the dataset as the region with the most unique flora from the local contribution to beta diversity analysis. Overall, the autecological data provided by our study will allow for improved interpretations of paleolimnological records and other biomonitoring efforts, addressing management concerns and contributing to a better understanding of our changing environment. [ABSTRACT FROM AUTHOR]

The reverse water gas shift (RWGS) is of great significance to the resource utilization of CO 2. In this paper, based on the features of MoO 3 , the Mo-based catalysts doped with Ga, Ti and Ce were prepared, and the effects of oxygen vacancies and basic sites on the RWGS reaction were studied. When the volume ratio of H 2 and CO 2 is 1 : 1, the yield of CO can reach 26.66%. Because it exposes higher concentration of Ce sites and moderate alkaline active sites on the surface. When the proportion of H 2 in the reaction gas increases, the highest yield of CO can reach 54.53%, which is mainly attributed to a large number of oxygen vacancies on the surface of MoTi. This study can be used as a reference for the design of catalysts for RWGS reaction under different reaction conditions. A series of Mo-based catalysts were prepared, and the significance of oxygen vacancies and surface basic sites in RWGS reaction was explored, and a reference was provided for the study of similar catalytic materials under different reaction gas ratios. [Display omitted] • MoO 3 by doping transition metal has a good application prospect in RWGS reaction. • The yield of MoTi and MoCe is close to equilibrium in RWGS reaction. • High CO 2 concentration is good for MoTi with higher density oxygen vacancies. • High H 2 concentration is good for MoCe with higher density surface basic sites. [ABSTRACT FROM AUTHOR]

Background: Potato serves as a major non-cereal food crop and income source for small-scale growers in Punjab, Pakistan. Unfortunately, improper fertilization practices have led to low crop yields, worsened by challenging environmental conditions and poor groundwater quality in the Cholistan region. To address this, we conducted an experiment to assess the impact of two fertilizer application approaches on potato cv. Barna using plant growth-promoting bacteria (PGPB) coated biofertilizers. The first approach, termed conventional fertilizer application (CFA), involved four split applications of PGPB-coated fertilizers at a rate of 100:75 kg acre–1 (N and P). The second, modified fertilizer application (MFA), employed nine split applications at a rate of 80:40 kg acre–1. Results: The MFA approach significantly improved various plant attributes compared to the CFA. This included increased plant height (28%), stem number (45%), leaf count (46%), leaf area index (36%), leaf thickness (three-folds), chlorophyll content (53%), quantum yield of photosystem II (45%), photosynthetically active radiations (56%), electrochromic shift (5.6%), proton flux (24.6%), proton conductivity (71%), linear electron flow (72%), photosynthetic rate (35%), water use efficiency (76%), and substomatal CO2 (two-folds), and lowered non-photochemical quenching (56%), non-regulatory energy dissipation (33%), transpiration rate (59%), and stomatal conductance (70%). Additionally, the MFA approach resulted in higher tuber production per plant (21%), average tuber weight (21.9%), tuber diameter (24.5%), total tuber yield (29.1%), marketable yield (22.7%), seed-grade yield (9%), specific gravity (9.6%), and soluble solids (7.1%). It also reduced undesirable factors like goli and downgrade yields by 57.6% and 98.8%, respectively. Furthermore, plants under the MFA approach exhibited enhanced nitrogen (27.8%) and phosphorus uptake (40.6%), with improved N (26.1%) and P uptake efficiency (43.7%) compared to the CFA approach. Conclusion: The use of PGPB-coated N and P fertilizers with a higher number of splits at a lower rate significantly boosts potato production in the alkaline sandy soils of Cholistan. [ABSTRACT FROM AUTHOR]

Bonneville cutthroat trout (Oncorhynchus clarkii utah) have experienced substantial declines in their historical distribution and abundance, and recent status assessments have noted a particular lack of information on abundance trends for the species. From 1993 to 2020, a total of 186 backpack electrofishing surveys were conducted across 34 index reaches to monitor abundance of Bonneville cutthroat trout and nonnative salmonids in southeastern Idaho streams. Trout abundance (all species combined) for fish ≥100 mm (total length) averaged 7.6 fish/100 m2 of stream (3.1 fish/100 m). Bonneville cutthroat trout population growth rate (λ) was generally stable through time (mean λ = 1.04 across all reaches; 95% confidence interval, 0.98-1.10), whereas for nonnative trout considered collectively, estimates of λ in general were declining over the entire study period (mean λ = 0.93; 0.89--0.97). Although mean density of Bonneville cutthroat trout was higher at reaches where nonnative trout were absent (x = 7.7 fish/100 m²) than where they were present (x = 4.2 fish/100 m²), estimates of λ for cutthroat trout were not related to the abundance of nonnative trout. Bonneville cutthroat trout λ was also unrelated to all the reach-scale environmental conditions we measured except for conductivity, which was positively associated with λ. Conductivity is normally associated with the productivity of a water body, but it is also correlated to other important cations and anions (e.g., alkalinity and water hardness) that can influence fish populations in a number of ways; thus, we cannot ascertain whether the relationship we observed was causative or correlative. Bonneville cutthroat trout abundance was higher in years when both winter and summer discharge were higher in the previous year, which concurs with a large body of literature demonstrating that reduced baseflow during winter or summer can adversely affect salmonid recruitment, food resources, predatory avoidance, survival, and stream habitat conditions. [ABSTRACT FROM AUTHOR]

Aim: In salt‐affected environments, salinity shapes ecosystem functions and species composition. Apart from salinity, however, we know little about how soil chemical factors affect plant species. We hypothesized that specific ions, most of which contribute to salinity, co‐determine plant niche differentiation. We asked if the importance of ions differs for species with (halophytes) and without (associated species) physiological adaptations to saline soils. Location: Carpatho‐Pannonian region (Central and Eastern Europe). Time period: 2005–2021. Major taxa studied: Vascular plants. Methods: We recorded species occurrences and collected soil samples in 433 plots in saline habitats. We measured pH, salinity (electrical conductivity), and concentrations of Ca2+, K+, Mg2+, Na+, SO42− Cl−, CO32− and mineral nitrogen (mN) and calculated the sodium adsorption ratio (SAR). For 88 species, we fitted response curves with Huisman–Olff–Fresco (HOF) models. To study ions' effects on species composition and ions' variance, we compared unconstrained and constrained ordinations and performed a principal component analysis. We used random forests to analyse the importance of ions for individual species and created two‐dimensional species niche plots for key ions. Results: Ion concentration niches varied among species and did not necessarily correspond to soil salinity or alkalinity. We frequently observed monotonic, sigmoidal model responses, while skewed unimodal responses were rare. Ions explained a considerable proportion of species compositional variation. Particularly, Na+, SO42−, Cl−, and CO32− contributed to the ions' variance. Na+, followed by SO42−, Cl−, CO32−, Ca2+, Mg2+, and mN, was most important for the occurrence of individual species. Compared to associated species, Na+, SO42−, and mN were significantly less important for halophytes, whereas Cl− and CO32− played a significant role. Main conclusions: We show that ion composition co‐determines niche differentiation in saline soils, suggesting evolved physiological adaptations in halophytes. Our study calls for incorporating high‐resolution data on soil ion composition in ecological research. [ABSTRACT FROM AUTHOR]

The ocean carbon reservoir controls atmospheric carbon dioxide (CO2) on millennial timescales. Radiocarbon (14C) anomalies in eastern North Pacific sediments suggest a significant release of geologic 14C‐free carbon at the end of the last ice age but without evidence of ocean acidification. Using inverse carbon cycle modeling optimized with reconstructed atmospheric CO2 and 14C/C, we develop first‐order constraints on geologic carbon and alkalinity release over the last 17.5 thousand years. We construct scenarios allowing the release of 850–2,400 Pg C, with a maximum release rate of 1.3 Pg C yr−1, all of which require an approximate equimolar alkalinity release. These neutralized carbon addition scenarios have minimal impacts on the simulated marine carbon cycle and atmospheric CO2, thereby demonstrating safe and effective ocean carbon storage. This deglacial phenomenon could serve as a natural analog to the successful implementation of gigaton‐scale ocean alkalinity enhancement, a promising marine carbon dioxide removal method. Plain Language Summary: The ocean is the largest carbon reservoir on Earth's surface and, as such, it controls the concentration of the greenhouse gas carbon dioxide (CO2) in the atmosphere over long time periods. When CO2 was rising at the end of the last ice age, marine sediment evidence indicates a regional carbon release into the ocean, due to a distinct carbon isotope fingerprint left behind. Using a carbon cycle model and atmospheric data, we simulated different geologic carbon addition scenarios since the last ice age. We find that substantial carbon addition to the ocean could have occurred (up to 1.3 billion tons per year) without causing significant changes to the carbon cycle, but only if the carbon is neutralized by alkalinity in an approximate 1:1 ratio. This neutralized release is similar to an approach of carbon removal called ocean alkalinity enhancement (OAE), which aims to reduce atmospheric CO2 as a potential solution for climate change. These findings suggest that neutralized carbon addition—in the form of "neutralized" bicarbonate ion HCO3− $\left({\text{HCO}}_{3}^{-}\right)$ instead of "acidic" CO2—could explain the low levels of radiocarbon during the last deglaciation and shows that large‐scale OAE is feasible without causing major changes to the marine carbon cycle. Key Points: Observed deglacial changes in atmospheric CO2 and 14C/C allow for up to 2,396 Pg of neutralized geologic carbon (i.e., bicarbonate) releaseThe global carbon cycle is essentially "blind" to neutralized carbon release, only constrained by 14C budgetThis gigaton‐scale neutralized carbon release may be a natural analog to the marine CO2 removal method of ocean alkalinity enhancement [ABSTRACT FROM AUTHOR]

[Objective] To explore the remediation effect of biochar-chitosan composite (CBC) on Cd contaminated soil. [Method] A pot experiment was conducted with ryegrass as the test plant, the changes of soil pH, total Cd content, available Cd content, biomass of ryegrass roots and leaves, and total Cd content in acidic low Cd soil, neutral high Cd soil and alkaline high Cd soil were investigated when CBC was added to 0, 0.5%, 1.0% and 3.0% (W/W) respectively. [Result] The application of CBC could increase the pH of acidic and neutral soils. The available Cd decreased with the increase of CBC application, and reached a significant level when the application amount reached 3.0%.CBC could passivate Cd activity in soil, and its passivation effect was closely related to the degree of soil pollution and acid-base property. With the increase of CBC application, the Cd content in the roots and shoots of ryegrass decreased, especially the effect on the aboveground part of plants was significant, directly indicating that CBC had a immobilization effect on Cd in soil. The BCF and TF of ryegrass decreased with the increase of CBC application rate, indicating that the application of CBC could reduce the migration of Cd from soil to the plant body, thereby achieving the effect of alleviating Cd toxicity. [Conclusion] The CBC can be used for the remediation of Cd contaminated soil, especially in heavily polluted acidic soils. [ABSTRACT FROM AUTHOR]

Ecological porous concrete (EPC) is one of the novel formulations of concrete with unique phytogenic properties. However, achieving both low alkalinity and high strength in EPC proves challenging due to the inherently high alkalinity of the pore environment, which hinders the growth of the plant and affects its ecological benefits significantly. This research investigated the utilization of 15 types of chemical admixtures and diatomaceous earth as alkali-reducing agents to optimize the properties of silicate cementitious materials for the applications of EPC. To identify the most effective agents, the pH value and compressive strength of the cement paste were adopted as the screening criteria for the selection of the essential alkali-reducing ingredients. Subsequently, a composite approach combining chemical admixtures and DE was employed to explore the synergistic effects on the pH and strength of silicate cementitious materials. The results revealed that a combination of 8% DE, 5% oxalic acid, and 5% iron sulfate functioned effectively and resulted in desirable performance for the concrete. This synergistic blend effectively consumed a large amount of Ca(OH)2, reducing the pH of cement paste to 10.48 within 3 days. Furthermore, the hydration reaction generated C-S-H with a low Ca/Si ratio, leading to a remarkable increase in the compressive strength of the concrete, reaching 89.7 MPa after 56 days. This composite approach ensured both low alkalinity and high strength in silicate cementitious materials, providing a theoretical basis for the application and promotion of EPC in the ecological field. [ABSTRACT FROM AUTHOR]

Background: This study explores the impact of various light spectra on the photosynthetic performance of strawberry plants subjected to salinity, alkalinity, and combined salinity/alkalinity stress. We employed supplemental lighting through Light-emitting Diodes (LEDs) with specific wavelengths: monochromatic blue (460 nm), monochromatic red (660 nm), dichromatic blue/red (1:3 ratio), and white/yellow (400–700 nm), all at an intensity of 200 µmol m-2 S-1. Additionally, a control group (ambient light) without LED treatment was included in the study. The tested experimental variants were: optimal growth conditions (control), alkalinity (40 mM NaHCO3), salinity (80 mM NaCl), and a combination of salinity/alkalinity. Results: The results revealed a notable decrease in photosynthetic efficiency under both salinity and alkalinity stresses, especially when these stresses were combined, in comparison to the no-stress condition. However, the application of supplemental lighting, particularly with the red and blue/red spectra, mitigated the adverse effects of stress. The imposed stress conditions had a detrimental impact on both gas exchange parameters and photosynthetic efficiency of the plants. In contrast, treatments involving blue, red, and blue/red light exhibited a beneficial effect on photosynthetic efficiency compared to other lighting conditions. Further analysis of JIP-test parameters confirmed that these specific light treatments significantly ameliorated the stress impacts. Conclusions: In summary, the utilization of blue, red, and blue/red light spectra has the potential to enhance plant resilience in the face of salinity and alkalinity stresses. This discovery presents a promising strategy for cultivating plants in anticipation of future challenging environmental conditions. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate the effect of the alkaline sulfide (Na2S+NaOH) pre-identification process on cyanide leaching performance in oxidized refractory gold-silver ores. The ore has intensive oxide, carbonate, and silicate content, and contains Au/Ag minerals containing electrum, acanthite, and silver-bearing FePbZn Sulphate-Arsenate/Hydroxide minerals together with Fe, Pb, and Zn minerals. Niğde Ulukışla refractory Au/Ag ore has 8-9 g/T gold and 170-180 g/T silver grades. In mineralogical examinations, it was found that these metals were closed in minerals such as iron oxy/oxyhydroxide, calcite, and quartz or neighboring these minerals. In the cyanide soluble process after alkali sulfide preliminary procedure at room temperature, metal extraction yields were obtained as 62% for gold and 7% for silver. It is seen that silver is adversely affected by this process compared to the direct cyanidation process. However, after the hot alkali treatment process, metal extractions improved by approximately 25% of gold and 74% of silver. This increase in yield can be considered as converting Ag-oxyhydroxide into soluble Ag forms as a result of the effect of hot alkaline sulfur leaching on the cyanide process. The most important advantage of this decomposition process is to achieve high metal extraction efficiency in lower alkali concentrations. [ABSTRACT FROM AUTHOR]

Although thermokarst alas lakes of Central Yakutia are of great climatic and economic importance, there is currently virtually no information on microbial communities and microbial processes in these lakes. This paper characterizes the hydrochemical features and presents a primary analysis of the diversity of planktonic microbial communities in three alas lakes of Central Yakutia—Tyungulyu, Taby, and Kharyyalakh. It was shown that in terms of the water physicochemical composition, the studied lakes were quite typical for this region; they had increased alkalinity and trophicity, but differed from each other in microbiological indicators. Chemoheterotrophic prokaryotes predominated in the studied planktonic communities, but a significant proportion of the 16S rRNA gene sequences were most similar to uncultured microorganisms whose functional potential is still unknown. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effect of different management strategies on the toxic nitrogen compounds and alkalinity patterns in nurseries and pre-grow-out of Penaeus vannamei culture with low salinity water (2.5 g L−1) and synbiotic system. A study case is presented using three individual experiments (E): two nurseries (EI and EII: 2000 shrimp m−3 or 600 shrimp m−2) and one pre-grow-out (EIII: 300 shrimp m−3 or 90 shrimp m−2). Key water quality management strategies included the adoption of artificial substrate and water reuse with a microbial-based synbiotic system. In EI experiment, mean TAN was less than 0.50 mg L−1 throughout the culture, NO2−-N reached a maximum concentration of 0.80 mg L−1, and NO3−-N showed a decrease over the time. In EII, mean TAN was 0.64 mg L−1 with a peak on day 10 of the experimental course, with the same pattern occurring for NO2−-N. On the other hand, NO3−-N constantly increased from 0.10 mg L−1 at the beginning to 2.32 mg L−1 at the end of the trial. In EIII, mean TAN was less than 0.50 mg L−1 reaching a maximum concentration of 0.93 mg L−1; NO2−-N reached a maximum mean concentration of 0.70 mg L−1 at the end of the experiment. NO3−-N had a mean of 1.50 mg L−1 at the beginning of the experiment and a reduction to 0.53 mg L−1 at the end of the trial. Alkalinity showed mean concentrations of 114.90 mg L−1, 88.04 mg L−1, and 88.27 mg L−1 for EI, EII, and EIII, respectively. The results demonstrated that the proposed management protocols adopted in EI, EII, and EIII were efficient for toxic nitrogen control in culture conditions using low salinity water and synbiotic system. [ABSTRACT FROM AUTHOR]

This article focuses on the issues related to the primary nature and metamorphism of gneisses from the Larba block of the Dzhugdzhur–Stanovoy fold area, which are based on the study of the mineralogical composition of supracrustal rocks. The PT-parameters for the highest temperature and pressure metamorphic transformations of rocks of the Larba block are estimated as P = 6.5–8.5 kbar and T > 800°C. Relatively low-temperature garnet–biotite and garnet–biotite–chlorite mineral parageneses were formed at the regressive stage of metamorphism at ~4–6 kbar and temperatures up to 500–600°C. Wide variations in paragneiss compositions indicate that the studied gneisses were derived from protoliths of different composition. Overall, Larba metasedimentary rocks had weakly and moderately weathered source areas. Most of the compositions of paragneisses are located in the field of chlorite–montmorillonite, montmorillonite–kaolinite–hydromica, and chlorite clays formed from the mafic protolith. The low alkalinity in combination with a high MgO content indicates the presence of rock erosion products with a significant admixture of basic volcanic material in the detrital material. Migmatization of the rocks is the most significant factor that distorts the reconstruction of the original rock composition. [ABSTRACT FROM AUTHOR]

This study focused on evaluating the effect of different concentrations of nutrients and total suspended solids on the removal rate of nutrients and biocompounds from the macroalgae U. lactuca in an integrated system with the shrimp Penaeus vannamei in biofloc. The experiment lasted 45 days and included five treatments with three replicates each, with percentages of 0 (control), 25, 50, 75, and 100% biofloc inoculum (73.3 ± 5.7 and 325.0 ± 21.2 mg L−1 initial nitrate and solids, respectively, in the 100% inoculum), from a shrimp farm, resulting in different concentrations of solids and nutrients. The macroalgae were introduced into 280 L tanks at a density of 0.88 kg m−2, along with 200 shrimp m−3. The algae were separated by a floating structure. Water quality parameters were measured, and the nutrient removal rate was evaluated. The treatment with 75% inoculum showed a removal rate of 55.0 ± 4.0 and 31.0 ± 10.0% of nitrate and phosphate, respectively. There was no difference in macroalgae growth between the treatments; however, macroalgae grown in 75% inoculum had higher protein, chlorophyll-a, and lower ash values compared with the control. The use of macroalgae in integrated production with shrimp under the conditions of the treatment with 75% biofloc inoculum proved to be viable and sustainable. [ABSTRACT FROM AUTHOR]

Archived water quality data collected between 1901 and 2019 were used to reconstruct annual averages of various forms of C, N, P, and silicate concentrations and alkalinity in the lower Mississippi River. During this interval the average annual nitrate concentrations doubled pre-dominantly from fertilizer applications and tiling, silicate concentrations decreased by half as diatom sedimentation increased as dams were built, and alkalinity increased 16%. Variances in silicate concentrations were proportional to river discharge before 1980 and concentrations have been stable since then. Average annual temperatures, discharge and alkalinity increased simultaneously around 1980; this suggests that there was greater weathering thereafter and is supported by the positive relationships between variations in alkalinity and variations in nitrate, phosphate, and silicate concentrations. The conversion of forests and grasslands into farmlands and improved drainage resulted in less evapotranspiration, a higher percent of precipitation going into streams and altered soil water bio-geo-chemistries. Field trials demonstrating soil health improvements resulting from more live roots and soil cover and greater biodiversity demonstrate water quality improvements and no effect on farm profitability. Lowering nitrate loading to the coastal waters will reduce summertime hypoxic waters formation offshore, but alkalinity in the river will increase further with climate warming. [ABSTRACT FROM AUTHOR]

The balance between alkalinity generation by carbonate and silicate weathering and sulfuric acid generation by sulfide weathering controls the effect of weathering on atmospheric p CO 2 over geologic timescales. How this balance varies across environmental gradients remains poorly constrained. Here, we analyze this balance across an erosional gradient of two orders of magnitude in the Three Rivers (Yangtze, Mekong, and Salween Rivers) Headwater Region (TRHR), eastern Qinghai-Tibet Plateau (QTP). By employing major element chemistry and multiple isotopes (δ34S SO 4 , δ18O SO 4 , and δ18O H 2 O) coupled with forward and inverse approaches, we unmix contributions of silicates, carbonates, evaporites, and sulfides to the total weathering budget. Across the TRHR, riverine SO 4 2– is derived mainly from a mixture of an evaporite source with uniform values of δ34S SO 4 and δ18O SO 4 , and a sulfide source that contributes highly variable values of δ34S (−12.2 ‰ to +4.1 ‰) and δ18O (−17.7 ‰ to −1.6 ‰). Contributions of sulfide oxidation to riverine SO 4 2– vary from 16 % to 94 %, and sulfuric acid consumes 6 % to 63 % of the alkalinity produced by weathering. The fractions of weathering alkalinity derived from carbonate weathering range from 36 % to 98 % relative to silicate weathering. The combination of silicate, carbonate, and sulfide weathering suggests that the instantaneous weathering fluxes of most sampled catchments in the TRHR act as a sink of atmospheric CO 2 over timescales shorter than marine carbonate burial (∼104 years), but as a carbon source over timescales longer than carbonate burial and shorter than sulfide burial (∼107 years). The spatial variability of the balance between alkalinity and acid generation, and, thus, the relationship between chemical weathering and atmospheric p CO 2 , are largely dependent on lithology. However, within comparable lithologic settings, sulfide and carbonate weathering rates rise with increasing erosion, whereas silicate weathering rates remain constant. Consequently, plateau weathering shifts from a sink to a source of atmospheric CO 2 with increasing erosion. These findings suggest that sulfide weathering is more sensitive to erosion than carbonate and silicate weathering, and that it could play an important role in the long-term carbon cycle during mountain building. [ABSTRACT FROM AUTHOR]

The current study involved measuring the physical and chemical characteristics of the water of the Tigris River in Tikrit and its suburbs at five different sites for a period of six months. The results indicated significant variations across the study sites: turbidity ranged from 8,437 to 16,301NTU; conductivity from 191,833 to 202.38µS/cm; TDS from 382.77 to 412,944mg/L, and pH from 6.040 to 6.493. Dissolved oxygen levels ranged between 9.300 and 11.53mg/L, while biological oxygen demand varied from 2,922 to 4,016mg/L, and total alkalinity ranged from 56,888 to 62,444mg/L. Total hardness of the water at the sites ranged from 80,167 to 91,056mg/L, calcium hardness from 59,222 to 64,778mg/L, and magnesium hardness from 17,611 to 30,722mg/L. Furthermore, phosphate concentrations ranged from 3,339 to 3,449µg of phosphate atom/L, and silica concentrations from 3.40 to 4.58µg/L. While nitrite values ranged from 0.467 to 0.477µg of nitrogen atom/L. The results for monthly changes showed that the turbidity values were 4,278 to 24,644NUT, and the pH values were 5,469 to 7,250, while the dissolved oxygen values were 8.86 to 11.24mg/L, and the biological oxygen demand value was 3,500 to 3,826mg/L. Moreover, the results showed that the total hardness values ranged from 71,733 to 113,200mg/L, and phosphate values ranged from 2,998 to 4,808µg of phosphate atom/L, while nitrite values ranged from 0.454 to 0.532µg of nitrogen atom/L. [ABSTRACT FROM AUTHOR]

Background: The growing elderly population calls for specialized dietary options to address the unique nutritional needs of aging individuals. Current food production methods often overlook the dietary requirements of older adults. Expanding the range of gerodietic food products can significantly contribute to improving the health and well-being of the elderly. Methods: This study focuses on the development of gerodietic cookies, a pastry product enriched with key additives--phytolin, collagen hydrolysate, and trehalose. Organoleptic and physicochemical parameters of the cookies were evaluated using standard techniques. The formulated cookies aim to support collagencontaining tissues' health, reduce the risk of type 2 diabetes, and lower the product's glycemic index while maintaining an appealing taste and texture. Results: The synergistic effects of phytolin, collagen hydrolysate, and trehalose in the gerodietic cookies contribute to their potential health benefits. The study determined the optimal composition of these additives, ensuring their effectiveness and overall product quality. The enriched cookies displayed favorable characteristics, including uniform porosity, pleasant aroma, and taste, meeting the established standards for alkalinity, moisture content, and wetness. Conclusion: Developing gerodietic cookies with scientifically justified formulations offers a promising approach to address the dietary needs of the elderly population. These cookies have the potential to support collagen-rich tissues, mitigate the risk of type 2 diabetes, and provide a tasty and nutritious addition to the diet of older adults. This research contributes to the growing field of gerodietic nutrition, offering innovative solutions to promote healthy aging through dietary choices. [ABSTRACT FROM AUTHOR]

The agricultural sector faces challenges due to climate change and the growing global population. Alkaline stress could adversely impact plant growth and crop production. This stressor diminishes water quality essential for crop cultivation, consequently impairing plant growth and overall productivity. Gamma-aminobutyric acid (GABA), a non-protein amino acid, may exhibit multifaceted roles in plant responses to adverse environmental conditions. Optimization of crop production in controlled environmental agriculture under artificial light attracted much attention. In the present study, we investigated the effects of different light spectra and GABA concentrations on Lollo Rosso lettuce plants under alkaline stress. Seedlings were placed under different light spectra [red (R), blue (B), white (W), 3R:1B, and 2R:1B:1far red (FR)] and treated with GABA (0 and 50 µmol). Alkaline conditions were instituted by applying NaHCO3 at a concentration of 40 mM. The experiment incorporated a control treatment without NaHCO3. In general, R light exposure caused the highest growth performance of lettuce plants. GABA augmented biomass production in control and alkaline-treated plants across all light spectra. Additionally, it increased the concentrations of photosynthetic and protective pigments under alkaline conditions. GABA also improved the photosynthetic performance under all light spectra. Non-photochemical quenching and pigmentation were enhanced by exposure to B light, especially in plants treated with GABA. Alkaline stress induced an increase in soluble carbohydrate content in the lettuce leaves. These findings highlight the support of GABA application in facilitating coping plants to alkaline stress. [ABSTRACT FROM AUTHOR]

Three small-scale mock-up tests were carried out on artificially fractured Opalinus Clay samples from the lower sandy facies of Mont Terri site: the first with the synthetic water of neutral pH and at an osmotic suction of 1 MPa, the second with a highly NaNO3 saline solution with a neutral pH and at osmotic suction of 34 MPa, and the third with a hyperalkaline solution at pH = 13.5 and at osmotic suction of 1.16 MPa. The radial swelling pressure was monitored using a total pressure sensor along with the fracture opening using a displacement transducer. The tests ran for over 290 days. After that, the three tests were dismantled. A detailed petrophysical characterization of 45 subsamples was conducted, and the pore size distribution was determined at different positions. X-ray diffractometry measurements were also conducted to identify any mineralogical changes. Results show that, in the case of the synthetic water and the alkaline solution, the friction forces exerted by the lid and the base on the sample were significant and probably hampered the self-sealing of the fracture. Saline solutions affect the self-sealing process of claystones. Indeed, even though increasing the salinity caused the contraction of the diffuse double layer and generated additional fractures within the sample, which increased the permeability and thus accelerated the hydration process, a complete self-sealing of the fracture opening was not observed. [ABSTRACT FROM AUTHOR]

The objective of this study is to formulate vegetated light porous concrete (VLPC) through the utilization of various cementing materials, the design of porosity, and the incorporation of mineral additives. Subsequently, the study aims to assess and analyze key properties, including the bulk density, permeability coefficient, mechanical characteristics, and alkalinity. The findings indicate a linear decrease in the volume weight of VLPC as the designed porosity increases. While higher design porosity elevates the permeability coefficient, the measured effective porosity closely aligns with the design values. The examined VLPC exhibits a peak compressive strength of 17.7 MPa and a maximum bending strength of 2.1 MPa after 28 days. Notably, an escalation in porosity corresponds to a decrease in both the compressive and the bending strength of VLPC. Introducing mineral additives, particularly silicon powder, is shown to be effective in enhancing the strength of VLPC. Furthermore, substituting slag sulfonate cement for ordinary cement significantly diminishes the alkalinity of VLPC, resulting in a pH below 8.5 at 28 days. Mineral additives also contribute to a reduction in the pH of concrete. Among them, silica fume, fly ash, fly ash + slag powder, and slag powder exhibit a progressively enhanced alkaline reduction effect. [ABSTRACT FROM AUTHOR]

The co-occurrence of salinisation and alkalisation is quite frequent in problematic soils and poses an immediate threat to food, feed and nutritional security. In the present study, root system architectural traits (RSAs) and ion profiling were evaluated in 21 genotypes of Avena species to understand the effect of salinity-alkalinity stress. The oat genotypes were grown on germination paper and 5-day-old seedlings were transferred to a hydroponic system for up to 30 days. These seedlingswere subjected to seven treatments: T0, treatment control (Hoagland solution); T1, moderate salinity (50 mM); T2, high salinity (100 mM); T3, moderate alkalinity (15 mM); T4, high alkalinity (30 mM); T5, combined moderate salinity-alkalinity (50 mM + 15 mM); and T6, combined high salinity-alkalinity (100 mM and 30 mM) by using NaCl + Na2SO4 (saline) and NaHCO3 + Na2CO3 (alkaline) salts equivalently. The root traits, such as total root area (TRA), total root length (TRL), total root diameter (TRD), total root volume (TRV), root tips (RT), root segments (RS), root fork (RF) and root biomass (RB) were found to be statistically significant (P < 0.01) among the different genotypes, treatments and their interactions. Na+ and K+ content analysis in root and shoot tissues revealed the ion homeostasis capacity of different Avena accessions under stress treatments. Principal component analysis (PCA) covered almost 83.0% of genetic variation and revealed that the sharing of TRA, RT, RS and RF traits was significantly high. Biplot analysis showed a highly significant correlation matrix (P < 0.01) between the pairs of RT and RS, TRL and RS, and RT and RF. Based on PCA ranking and relative value for stress tolerance, IG-20-1183, IG-20-894, IG-20-718 and IG-20-425 expressed tolerance to salinity (T2), IG-20-425 (alkalinity; T4) and IG-20-1183, IG-20-894 and IG-20-1004 were tolerant to salt-alkali treatment (T6). Multi-trait stability index (MTSI) analysis identified three stable oat genotypes (IG-20-714, IG-20-894 and IG-20-425) under multiple environments and these lines can be used in salinity-alkalinity affected areas after yield trials or as donor lines for combined stresses in future breeding programs. [ABSTRACT FROM AUTHOR]

Total alkalinity (AT) and dissolved inorganic carbon (CT) in the oceans are important properties with respect to understanding the ocean carbon cycle and its link to global change (ocean carbon sinks and sources, ocean acidification) and ultimately finding carbon-based solutions or mitigation procedures (marine carbon removal). We present a database of more than 44 400 AT and CT observations along with basic ancillary data (spatiotemporal location, depth, temperature and salinity) from various ocean regions obtained, mainly in the framework of French projects, since 1993. This includes both surface and water column data acquired in the open ocean, coastal zones and in the Mediterranean Sea and either from time series or dedicated one-off cruises. Most AT and CT data in this synthesis were measured from discrete samples using the same closed-cell potentiometric titration calibrated with Certified Reference Material, with an overall accuracy of ±4 µ mol kg -1 for both AT and CT. The data are provided in two separate datasets – for the Global Ocean and the Mediterranean Sea (10.17882/95414, Metzl et al., 2023), respectively – that offer a direct use for regional or global purposes, e.g., AT –salinity relationships, long-term CT estimates, and constraint and validation of diagnostic CT and AT reconstructed fields or ocean carbon and coupled climate–carbon models simulations as well as data derived from Biogeochemical-Argo (BGC-Argo) floats. When associated with other properties, these data can also be used to calculate pH, the fugacity of CO 2 (f CO 2) and other carbon system properties to derive ocean acidification rates or air–sea CO 2 fluxes. [ABSTRACT FROM AUTHOR]

Bonneville cutthroat trout (Oncorhynchus clarkii utah) have experienced substantial declines in their historical distribution and abundance, and recent status assessments have noted a particular lack of information on abundance trends for the species. From 1993 to 2020, a total of 186 backpack electrofishing surveys were conducted across 34 index reaches to monitor abundance of Bonneville cutthroat trout and nonnative salmonids in southeastern Idaho streams. Trout abundance (all species combined) for fish ≥100 mm (total length) averaged 7.6 fish/100 m² of stream (3.1 fish/100 m). Bonneville cutthroat trout population growth rate (λ) was generally stable through time (mean λ = 1.04 across all reaches; 95% confidence interval, 0.98–1.10), whereas for nonnative trout considered collectively, estimates of λ in general were declining over the entire study period (mean λ = 0.93; 0.89–0.97). Although mean density of Bonneville cutthroat trout was higher at reaches where nonnative trout were absent (x̅ = 7.7 fish/100 m²) than where they were present (x̅ = 4.2 fish/100 m²), estimates of λ for cutthroat trout were not related to the abundance of nonnative trout. Bonneville cutthroat trout λ was also unrelated to all the reach-scale environmental conditions we measured except for conductivity, which was positively associated with λ. Conductivity is normally associated with the productivity of a water body, but it is also correlated to other important cations and anions (e.g., alkalinity and water hardness) that can influence fish populations in a number of ways; thus, we cannot ascertain whether the relationship we observed was causative or correlative. Bonneville cutthroat trout abundance was higher in years when both winter and summer discharge were higher in the previous year, which concurs with a large body of literature demonstrating that reduced baseflow during winter or summer can adversely affect salmonid recruitment, food resources, predatory avoidance, survival, and stream habitat conditions. [ABSTRACT FROM AUTHOR]

The cement mortar lining (CML) of commonly used ductile iron pipes can severely deteriorate the drinking water quality at the initial stage of use, but the behavioral characteristics of different elements release from the CML in this stage is still unclear. In this study, dynamic immersion experiments with new cement mortar lined ductile iron pipe reactors were conducted under different feed water hardness and alkalinity conditions. The results showed that the release of alkaline substances from the CML at the initial stage of use could strongly influence the pH of water, which consequently greatly impacted the release/precipitation behaviors of calcium, aluminum and silicon. The pH and aluminum concentration of the effluent water could reach 11.5 and 700 µg/L within 24 hr of hydraulic retention time, respectively, under conditions of relatively lower hardness and alkalinity. Due to the pH elevation, calcium carbonate precipitation could occur even at much lower feed water alkalinity. Whereas the aluminum and silicon could keep release from the CML in soluble form at different hardness and alkalinity levels, and their release rate depended on the amount of calcium carbonate precipitation. Thus, aluminum and silicon were more suitable as indicators of the corrosion intensity at the initial stage of CML use rather than the traditional calcium carbonate precipitation potential. Appropriate feed water hardness and alkalinity levels for mitigating the initial intense corrosion of CML were proposed: hardness > 40 mg/L (CaCO 3), alkalinity > 100 mg/L (CaCO 3). [ABSTRACT FROM AUTHOR]

The carbonation behavior of alkali-activated materials (AAMs) over time is crucial for structural durability. In this study, accelerated carbonation tests were conducted on alkali-activated slag-metakaolin (AASM) composite pastes. The effects of various slag content at 0%, 20%, and 40%, and Na 2 O content at 15%, 17%, 19%, 21%, and 23% on the pore structure, carbonation depth, and material alkalinity of AASM composite pastes were studied. The research results indicated that with the increase in slag content and Na 2 O content, the pore structure of AASM composite pastes tended to become denser. The influence of slag content and Na 2 O content on the early carbonation depth was significant. In the 0% slag content group, the carbonation depth at 3d of accelerated carbonation decreased by 61.4% when the Na 2 O content increased from 15% to 23%. With the increase in slag content, the effect of Na 2 O content on carbonation depth tended to weaken. In the 40% slag content group, the carbonation depth at 3d of accelerated carbonation remained below 10 mm. As accelerated carbonation progressed, the measured pH value rapidly decreased before 7d of accelerated carbonation and gradually stabilized thereafter. Based on pore structure parameters, predictive models for carbonation depth and material alkalinity of AASM composite pastes were constructed. The results of the accelerated carbonation test were used to validate the model calculations. The results show that the model based on pore structure parameters can effectively predict the carbonation depth and material alkalinity of AASM composite pastes. • The most probable pore diameter and porosity of alkali-activated slag-metakaolin (AASM) composite pastes are investigated. • Combined with the theoretical carbonation coefficient of AASM composite pastes, a predictive model for carbonation depth is established. • The alkalinity prediction model is proposed based to the equilibrium relationship between the ions in the pore solution. • Compared with the experimental results, the proposed carbonation depth and alkalinity models have high applicability. [ABSTRACT FROM AUTHOR]

Bauxite residue (red mud) has high alkalinity and salinity, which seriously restricts its reuse. It is crucial to understand the salt distribution pattern and alkalinity characteristics in the bauxite residue disposal area (BRDA), which can provide a theoretical basis for realizing the salinity and alkalinity regulation and reuse of bauxite residue. In this paper, samples from different locations and depths of the BRDA were used for the determination of soluble salts content, pH, and electrical conductivity (EC), and the correlation between the indicators was analyzed. The results show that bauxite residue has a high content of soluble salts, and the spatial distribution of soluble salts in the BRDA is relatively complex, with moderate variability, but does not show an obvious regularity. The major cations are Na+, K+ and the major anions are CO 3 2−, HCO 3 −. Through cluster analysis, the soluble ions in bauxite residue can be divided into two main groups, one is Na+, CO 3 2−, HCO 3 −, and the other is Ca2+, Mg2+, K+, Cl− and SO 4 2−. PH has a significant positive correlation with Na+, K+, CO 3 2− and HCO 3 −, and a negative correlation with Ca2+. And its alkalinity depends to a large extent on carbonate and bicarbonate, and the Na+ content can be predicted from EC, thus reflecting the concentration of alkaline residues in the bauxite residue. [Display omitted] • The distribution of soluble salt ions varies widely within the BRDA. • The main ions in bauxite residue are Na+, CO 3 2− and HCO 3 −. • The alkalinity is largely dependent on the concentrations of CO 3 2− and HCO 3 −. • An equation for predicting alkaline residues from EC was proposed. [ABSTRACT FROM AUTHOR]

In this study, the impact of salinity and alkalinity on the volumetric deformation of the Opalinus Clay from the lower sandy facies (LSF\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\text{LSF}$$\end{document}) of Mont Terri site was investigated. Series of samples were exposed in parallel to alkaline solutions at four different pHs\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\text{pHs}$$\end{document} (8.8,11.5,12.5\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$8.8, 11.5, 12.5$$\end{document} and 13.5\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$13.5$$\end{document}) or to saline solutions at three different osmotic suctions (π = 10,15\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$10, 15$$\end{document} and 34MPa\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$34\,\text{MPa}$$\end{document}). As a reference, samples were also exposed to synthetic water at pH7.5\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\text{pH}\, 7.5$$\end{document} and π = 1MPa\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$1\, \text{MPa}$$\end{document}. It was found that the protocol followed above (“parallel testing”) was not suitable for the LSF\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\text{LSF}$$\end{document} Opalinus Clay due to the high mineralogy variability. Therefore, a new protocol (“gradual testing”) consisting of gradually exposing the same sample to different saline or alkaline solutions was adopted. It was found that the volumetric swelling strain increased with alkalinity and decreased with salinity. In the first case, the acid-base attack resulted in a dispersed structure with higher repulsive forces. Also, the precipitation of new compounds composed of the products of the dissolution of clay minerals and the species present in the alkaline solution contributed to the observed increase in swelling strain. For the saline solutions, the decrease of the thickness of diffuse double layer and the osmotically induced consolidation explained the observed decrease of swelling strain. [ABSTRACT FROM AUTHOR]

In recent years, saline–alkaline aquaculture development has become an important measure for China to expand its fishery development space to ensure food safety. Previous studies have verified that salinity and alkalinity positively influence the quality of Chinese mitten crabs (Eriocheir sinensis). However, the regulatory mechanism of E. sinensis endures saline–alkaline stress which remains obscure. This study investigated the metabolic changes in puberty-molting E. sinensis gills exposed to freshwater (FW), sodium chloride salinity of 5 ppt (SW), and carbonate alkalinity 10.00 mmol/L (AW) for 50 days using untargeted liquid chromatography-mass spectrometry metabolomics (LC–MS). A total of 5802 (positive-ion mode) and 6520 (negative-ion mode) peaks were extracted by LC–MS, respectively. A total of 188 (50 upregulated and 138 downregulated), 141 (94 upregulated and 47 downregulated), and 130 (87 upregulated and 43 downregulated) significantly regulated metabolites (SRMs) were observed in the FW–SW, FW–AW, and SW–AW treatments, respectively, wherein 42 generic SRMs were also found by Venn diagram analysis. Seven of the top 10 SRMs with the highest (variable importance in projection) VIP values were similarly identified in FW–SW and SW–AW. Integrated analysis of key metabolic pathways revealed glycerophospholipid, choline in cancer, phenylalanine, and butanoate metabolism. Overall, significant differences were observed in the metabolites and key metabolic pathways of E. sinensis gill exposed to salinity and alkalinity stress. These results will be helpful in understanding the environmental adaptability of aquatic crustaceans to saline–alkaline water. [Display omitted] • Significantly regulated metabolites are checked by saline–alkaline stress to Eriocheir sinensis. • Glycerophospholipid metabolism is observed for Eriocheir sinensis to saline–alkaline stress. • Tryptophan and phenylalanine catabolism can reduce the damage caused by saline–alkaline stress. [ABSTRACT FROM AUTHOR]

The chemical actions of the lapping fluid have been proven to enhance the machinability of fixed abrasive pad (FAP). However, the wear mechanisms and removal mechanisms of FAP under different pH conditions remain unclear. Therefore, the influences of the pH of the lapping fluid on the processing characteristics (hardness, micro-cutting performance, surface morphology) of FAP and the material properties (hardness, depths of critical brittle-plastic transition) of the workpieces were explored in the study. The wear mechanisms and removal mechanisms of FAP under different pH conditions were systematically studied from three aspects: the chemical actions of the lapping fluid, the mechanical actions of FAP, and the vortex actions of chips. The results showed that the wear mechanism of FAP was mainly influenced by the chemical actions of lapping fluid and vortex actions of chips. Compared to neutral conditions, alkaline conditions to improved the glazing and self-trimming of FAP, with an increased in proportion of plastic removal of FAP, a 47.02% increase in material removal rate (MRR), and a 38.7% decrease in Sa. Conversely, acidic conditions accelerated the wear of FAP, brittle removal was the main processing method, which result in a 58.42% decrease in MRR, and a 20.42% increase in Sa. This study provides important guideline for enhancing the lapping efficiency of FAP in hard and brittle materials. • The wear mechanism of the FAP under different pH conditions was explored. • The removal mechanism of the FAP under different pH conditions was explored. • The influence of the synergistic action on the wear mechanism and removal mechanism of FAP were studied. [ABSTRACT FROM AUTHOR]

Ooids are a common constituent of carbonate rock throughout the last 3.2 billion years. The chemical and physical characteristics of ooids record essential details of the carbonate chemistry and hydrodynamic conditions of their depositional environment. As a result, ooids may be a powerful tool for reconstructing Earth's ancient climates and environments. However, lack of constraints on fundamental aspects of ooid formation, such as the role of abrasion, underscores the potential for additional discoveries utilizing ooids as paleoenvironmental proxies. Here, we use three-dimensional models built by serially grinding and imaging ooids to show how ooid shape changes during growth. We find that ooid abrasion plays only a small role in the formation of ooids, even in giant ooids, where the mass should cause abrasion to be most intense. A lack of abrasion during ooid formation suggests a greater sensitivity of ooid distribution and size to the chemistry of depositional environments. This insight enables us to harmonize our understanding of ooid formation with longstanding questions regarding their spatial and temporal distribution, as well as size variations. With a new database of ooid occurrences, we analyze the influence of seawater chemistry, carbonate shelf area, and evolutionary developments on ooid abundance in the Modern, Last Glacial Period, and throughout the Phanerozoic. Finally, we leverage our new understanding of ooid growth to show how ooid size, including giant ooids, can shed light on relative changes in alkalinity throughout the Phanerozoic. [ABSTRACT FROM AUTHOR]

Amine-free synthesis of high silica ZSM-5 with high crystallinity and well-defined morphology was challenging. In this work, ZSM-5 with the fed silica-alumina ratio (SAR) of 100 was rapidly synthesized with the assistance of the calcined silicalite-1 seed and ethanol, and their crystal structures, morphology and microporous properties were characterized by XRD, SEM, FT-IR, ICP and N 2 adsorption-desorption and so on. Firstly, the crystallization temperature was optimized between 140 and 180 °C at a certain alkalinity and ethanol content, and 160 °C was selected to not only provide high crystallization rate but also ensure the stability of high-silica skeleton. Secondly, the influences of the EtOH/SiO 2 ratio, Na 2 O/SiO 2 ratio and crystallization time on the crystallization of high-silica ZSM-5 were investigated at 160 °C. The results showed well-crystalline high-silica ZSM-5 could be synthesized within a wide range of the EtOH/SiO 2 ratios (0.5–2.0) and the increase of ethanol content slightly inhibited the growth of ZSM-5 along b-axial of hexagonal prisms due to the preferential adsorption of excess ethanol on the {010} crystal plane and the formation of Si–O–C 2 H 5 ; high alkalinity was favorable for the preparation of a small-sized and well-crystalline ZSM-5 due to the rapid depolymerization of calcined seed and the contribution of mass nucleation sites; meanwhile, excellent micropore characteristic of high-silica ZSM-5 further proved that the synthetic strategy of seed + ethanol was feasible. Finally, the synergistic action mechanism of calcined seed and ethanol for the synthesis of high-silica ZSM-5 was revealed that silicalite-1 with MFI structure unit combined with Na+(H 2 O/EtOH) with larger radius were very important for rapidly assembly of a large number of silica species into MFI framework. [Display omitted] • Complete amine-free synthesis of high-silica ZSM-5 was achieved via calcined silicalite-1 as seed. • High alkalinity can promote the depolymerization of silicalite-1 to obtain smaller-sized ZSM-5. • Silicalite-1+ethanol route could effectively inhibit magadiite and obtain high-crystalline ZSM-5. • Synergistic assembly mechanism of silicalite-1 and Na+(H 2 O/EtOH) with a large radius was put forward. [ABSTRACT FROM AUTHOR]

Mg(OH) 2 dissolves slowly and can provide a long-term source of alkalinity, thus a promising alternative reagent for the in situ remediation of heavy metal polluted groundwater. Unfortunately, it exhibits a relatively poor stabilization effect on heavy metal Cd due to the higher solubility of the resulting stabilized product, Cd(OH) 2. To overcome this limitation, we investigated the use of MgCO 3 /Mg(OH) 2 colloid modified by sodium polyacrylate (PAAS) to remove Cd from groundwater. Through ultrasonic dispersion, the molecular chains of PAAS are broken, causing a transformation from flocculation to surface modification, resulting in the production of a stable colloid. The colloidal particles of MgCO 3 /Mg(OH) 2 have a smaller size and a negatively charged surface, which significantly enhances their migration ability in aquifers. The combination of MgCO 3 and Mg(OH) 2 provides a complementary effect, where MgCO 3 effectively precipitates Cd in the aquifer while Mg(OH) 2 maintains the required pH level for stabilization. The optimal compounding ratio of MgCO 3 to Mg(OH) 2 for achieving the best stabilization effect on Cd is found to be 1:1. Column experiments demonstrate that the injection of MgCO 3 /Mg(OH) 2 colloid substantially enhances Cd stability, reducing the exchangeable fraction of Cd in aquifer media from 88.61% to a range of 22.50–34.38%. Based on these results, the MgCO 3 /Mg(OH) 2 colloid shows great potential as a reactive medium for remediating Cd-contaminated groundwater. [Display omitted] • MgCO 3 /Mg(OH) 2 colloid was proposed as a novel reagent for Cd-contaminated groundwater remediation. • Ultrasound can transform the flocculation effect of PAAS on MgCO 3 /Mg(OH) 2 particles into dispersion. • MgCO 3 effectively precipitates Cd and Mg(OH) 2 maintains the necessary pH level for stabilization. • A remarkable decrease in the exchangeable fraction of Cd in aquifer media after the injection of the MgCO 3 /Mg(OH) 2 colloid. [ABSTRACT FROM AUTHOR]

This study examines the role of alkalinity in the time-dependent carbonation characteristics, microstructural evolution, and strength of γ-C 2 S (also known as gamma-dicalcium carbonate or γ-belite) paste. γ-C 2 S paste is prepared using calcium hydroxide solutions at pH levels of 7, 8, 10, and 12, followed by CO₂ curing for 5, 10, 24, and 48 h, and characterized at multiscale by techniques such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and mercury intrusion porosimetry (MIP). Results show that higher alkalinity enhances the carbonation degree of γ-C 2 S, leading to an increase in calcium conversion degree (CCD), with calcite identified as the primary crystalline carbonation product. An alkalinity-dependent carbonation kinetics model is constructed. At pH 12, the γ-C 2 S paste exhibits the richest carbonation products, a dense microstructure, and achieves its highest strength (45.6 MPa) and CCD (62 %) after 48 h of CO₂ curing. Alkaline environments influence the carbonation of γ-C 2 S by modulating HCO 3 -/CO 3 2- concentration in the mixture and impact the strength development by affecting the quantity and crystallinity of carbonation products. • Enhanced γ-belite carbonation at higher alkalinity. • Model linking alkalinity to the γ-belite carbonation. • Alkalinity impacts γ-belite strength via carbonation. • Optimal pH revealed for γ-belite structure and strength. [ABSTRACT FROM AUTHOR]

pH of the growth solution of nanomaterials has been employed as a controlling agent in the morphology and synthesis of various metal oxides. The key points in the reconciliation with the thus formed nanostructures inevitably revolve around the impact of H+ and OH- ions on the oxide phases formed during various stages of the phase evolution. Here, a careful elucidation of acidic and alkaline conditions that influence the evolution of the perovskite of Strontium titanate (STO) has been done taking care to avoid the influence of other reagents by avoiding their use altogether. Multiple incremental steps of the growth solution's pH were the only variable, allowing a direct correlation of the alkalinity with the several interesting materializations of the perovskite composition. The fundamental aspects on the development of the different phases such as the lattice strains due to expansions and contractions of the lattice, integration of shallow level defects as a result of the growth conditions, visualizations of the interfaces between multiple phases which were always present when the growth conditions were not completely alkaline have been revealed through different structural and morphological characterizations. The catalytic property of the samples prepared at different pH levels investigated using UV light exhibited markedly different photocatalytic activity toward Rhodamine B (RhB). We propose that the tuned phase compositions and morphologies are the reason for the observed variations. The different compositions of intermediaries are interesting candidates for different applications that are concerned with defect and interface engineering, and the data presented herewith reveal precise conditions for achieving each of these interesting compositions as well as realizing pristine STO without the typical presence of secondary phases such as carbonates. [Display omitted] [ABSTRACT FROM AUTHOR]

Porous vegetation eco-concretes (PVEC) meet the initial growth needs of plants due to the fillers in pores containing soil and nutrients. The much higher permeability and biocompatibility than traditional compact concrete endow them as ecological material with wide applicability, and of course the performance requirements differ in different application scenarios. This review paper starts from the perspective of application requirements and delves into the relationship between material design and performance of PVEC, such as porosity, mechanical strength, alkalinity, durability, and plant growth performance. It gives a comprehensive understanding and the state-of-the-art research progress of PVEC, providing the guidance for future raw materials selection, structural design and application. [ABSTRACT FROM AUTHOR]

To tackle the issue of phosphorus (P) supply, Sewage Sludge Ash (SSA) is a promising secondary source. The goal of this research is the optimization of the wet P extraction process in the view of providing valuable insights for the process scale-up. While most of the studies relied on the "one-variable-changed-at-a-time" approach, this work applied a statistical optimization model based on the Design of Experiments technique for investigating the influence of most relevant operating conditions of extraction process on Phosphorus Extraction Efficiency (PEE) with two types of SSA characterized by different levels of alkalinity. Experimental results highlighted the importance of ash characteristics, making some SSA not suitable for cost-effective phosphorus recovery due to the high acid dosage required in extraction process. Type of acid and contact time become significant factors only for Ca-rich ashes, especially when using H 2 SO 4 as extracting agent. Optimal operating conditions (C H 2 SO4 = 1.3 N, L/S = 20, t = 2 h and C HCl = 2.0 N, L/S = 10, t = 2 h for Ash#1 and C H2SO4/HCl = 0.8 N, L/S = 10 for Ash#2) resulting in high PEE (80–94%) were identified for extraction performed with H 2 SO 4 and HCl as a function of ash characteristics. [Display omitted] • pH and ash alkalinity significantly affect acid dosage in P extraction process. • Reduced order models clarified the effects of factors and their interaction on PEE. • HCl was slightly (5%) more effective than H 2 SO 4 for Ca-rich ash. • The selection of optimal operating conditions is dependent on ash characteristics. • P, Fe and Al dissolution is a quick process when dealing with ash with low alkalinity. [ABSTRACT FROM AUTHOR]

A new type of multilayered plant-growing concrete was proposed in this work based on aggregate-bed 3D printing. Ordinary Portland cement (OPC) and low-alkalinity sulphoaluminate cement (LSAC) were used as binders for the printing mortar. The printing began by extruding the first layer mortar, and then coarse aggregates were spread on top of the mortar. Repeating these two steps multiple times finally manufactured the proposed plant-growing concrete where the plant seeds associated with soil were sown in the pores of the aggregate layers. Printability, pore structures, porosity, plant-growing quality, mechanical strengths, alkalinity, crystal phases, permeability, and stress distributions of the printed specimens were investigated. Results showed the printability of LSAC specimens was better than that of OPC specimens due to higher contents of sulphoaluminate in the LSAC specimens which consumed more water and thus resulted in drier and stronger printing mortar. The pores in the printed plant-growing concrete were connected into permeable networks allowing water to flow in and plants to grow in. The porosity and permeability of LSAC specimens were higher than those of OPC specimens due to the better printability of LSAC specimens which resulted in more connected pores, whereas the alkalinity of LSAC specimens was lower. All these led to the better plant-growing quality of LSAC specimens. Portlandite and ettringite, which were more abundant in OPC specimens, contributed more to the alkalinity of the printed concrete. The mechanical strengths of the printed plant-growing concrete showed distinct anisotropy, which was contributed by different layers playing critical roles in the strength tests. Nevertheless, ordinary materials and printing paths were used in this work, which can be varied and optimized in future studies and applications. [Display omitted] ● Plant-growing concrete was manufactured by aggregate-bed 3D printing. ● Sulphoaluminate increased printability but decreased alkalinity of concrete. ● Better printability led to higher porosity and permeability for aggregate-bed printing. ● Plant grew better in printed concrete with lower alkalinity and higher porosity. [ABSTRACT FROM AUTHOR]

The absence of portlandite and lower alkalinity in the supersulfated cement (SSC) system make it sensitive to being carbonated, especially, since the early-age carbonation would suppress the further hydration of SSC and its performance development. Here, the low-calcium silicate minerals (C x S, hydration active or non-active) were used as carbonation mitigation agents and were systematically investigated for their effects on SSC carbonation. It was found that hydration active minerals – C 3 S 2 and β-C 2 S present negative effects no matter on the hydration and carbonation mitigation aspects due to the more reactive hydraulic minerals would suppress the hydration of slag itself and thereby lowed the hydration degree of SSC. For non-hydration active minerals, α-CS polymorphs have little effect on the hydration of SSC. Unfortunately, they are carbonation unactive in the SSC system, and negative for mitigation of carbonation either. Only β-CS and γ-C 2 S are valid in mitigation carbonation of SSC with reasonable content (for β-CS over 20 wt % and γ-C 2 S over 10 wt %). The incorporation of high-carbonation activity minerals maintained the integrity of hydrates in SSC and reduced the porosity of the carbonated matrix mainly by scarifying themselves to carbonation and protect the hydrates, as consequence, mitigating the carbonation and favoring the strength maintenance of SSC. • The carbonation performances of supersulfated cement (SSC) have been systematically investigated. • A new scarifying protection carbonation mitigation strategy for SSC has been present. • Hydraulic non-hydraulic calcium silicates minerals were used for mitigate carbonation of SSC. [ABSTRACT FROM AUTHOR]

Acidity and alkalinity of water environments have been proven to influence the water stability of asphalt mixture. However, the relevant influencing mechanism still remains unclear. To fulfill this research gap, this study conducted a series of microscopic tests, aiming at unveiling the microscopic erosion mechanism of the water environment on the water stability of asphalt mixture for better moisture stability achieved. Specifically, the asphalt-aggregate interfacial transition zone (ITZ) samples were prepared by combining #70 asphalt with limestone and granite, respectively, which were then immersed in water solutions at 3 different pH levels (pH = 3.0, 7.0, and 11.0) for 7 days. The chemical composition and microstructure of the asphalt film on the surface of the ITZ samples pre and post-treatment were scrutinized using the Fourier Transform Infrared Spectroscopy (FTIR) and the Atomic Force Microscope (AFM), while the development of microcracks at the asphalt-aggregate interface were identified and traced utilizing the Scanning Electron Microscope (SEM). The test results indicate that after treatment with acidic and alkaline aqueous solutions, the asphalt film's surface is enriched with polar components such as asphaltenes, resins, and aromatic fractions. The migration of these polar components to the surface of the asphalt film reduces the adhesion between asphalt-aggregate, leading to the formation of microcracks at the asphalt-aggregate interface. The most severe crack development occurs in alkaline water environment, followed by acidic water environment. It is interestingly noted that the adhesion at the asphalt-granite interface is improved under the acidic environment. This improvement may be attributed to the covalent nature of silica, which hinders the adsorption of ions from acidic solution into the asphalt film. This hindrance effectively prevents water intrusion at the asphalt-aggregate interface, thereby reducing the adhesion loss. These findings can help elucidate the mechanism of water damage in asphalt pavement exposed to real-world conditions and enhance its water stability with effective countermeasures proposed. [Display omitted] • The asphalt-aggregate ITZ samples were prepared and conditioned under water environment at 3 different pH levels for 7 days. • The microstructure of the ITZ asphalt film was investigated through the AFM test. • The chemical composition change of the ITZ asphalt film was detected using the FTIR test. • The microcrack evolution at the asphalt-aggregate interface was identified matrixed on the SEM test. • The reliability of microscopic test results was verified through the modified pull-off test. [ABSTRACT FROM AUTHOR]

As a multifunctional organ, the gill plays a key role in the regulation of homeostasis. Excessive alkalinity in water can seriously threaten the survival of aquatic animals, however, the studies on the mechanism of alkalinity stress and adaption of crustacea are still limited. In this study, we aimed to investigate the mechanisms of acute alkalinity stress in the gill of Pacific white shrimp Litopenaeus vannamei by integrating physiological, histological, transcriptome, and metabolome analyses, which is an important aquaculture species of crustaceans. The physiological parameters related to homeostasis regulation, oxidative stress, material metabolism, and ammonia detoxification were significantly changed under acute alkalinity stress. There were a considerable number of genes and metabolites that were significantly changed in expression and level, which related to glycolysis/gluconeogenesis, fatty acid metabolism, amino acid metabolism, antioxidation, ammonia metabolism, and glycerophospholipid metabolism, In addition, the local structure of the gill was damaged and accompanied by cell apoptosis. The above results indicate that acute alkalinity stress can lead to damage to the gill structure, and affect its ion transport function, and the genes related to ion transport protein were upregulated. The antioxidant capacity in the gill was strengthened under acute alkalinity stress, at the same time, acute alkalinity stress would induce apoptosis in the gill. The glycogen catabolism in gill was significantly enhanced under acute alkalinity stress, while the lipid anabolism was inhibited, and the mechanism of the ornithine-urea cycle has been further mobilized to alleviate the inhibition of ammonia excretion and the accumulation of metabolic ammonia in the internal environment. In addition, the glycerophospholipid metabolism in the gill was disturbed under acute alkalinity stress. The current study will provide important clues for understanding the alkalinity stress mechanism of crustaceans, and provide an important theoretical basis for the optimization of shrimp aquaculture in saline-alkaline waters. • Acute alkalinity stress can lead to damage to the gill structure. • The antioxidant capacity in gill was strengthened under acute alkalinity stress. • Acute alkalinity stress would induce apoptosis in gill. • Energy metabolism was changed in gill under acute alkalinity stress. • The mechanism of ornithine-urea cycle has been further mobilized. • The glycerophospholipid metabolism in the gill was disturbed. [ABSTRACT FROM AUTHOR]

By considering the current global challenges such as greenhouse gas emission and waste disposal management, the exploration of geopolymer concrete is highly focused now-a-days. On the other hand, the use of costlier commercial activators acted as the major drawback for the practical existence. Although the recent geopolymer researchers suggested the use of alternative activators from various resources such as palm oil ash, olive ash etc, the application of which are not appreciably promoted due to the complex derivation process. To overcome these effects, in this paper, first time, an attempt is initiated to develop a cost-effective geopolymer concrete by using textile mercerizing water as an alternate activator system. The viability of using mercerizing water instead of commercial sodium hydroxide activator was studied initially. By conducting the pH electrode test and Infrared Analysis, the alkalinity and the presence of sodium metal cations responsible for the reaction kinematics were confirmed. Also, the molar concentration of sodium cations in the mercerizing water was quantified using chemical titration analysis. The feasibility of using mercerizing water in the preparation of geopolymer was assessed using workability, mechanical strength and sustainability. From the results, it was inferred that the developed geopolymer concrete with 100 % textile mercerizing water exhibited the maximum strength of 46.9 MPa, 5.16 MPa and 5.81 MPa respectively under compression, tension and flexure which are almost equivalent and slightly better than the control geopolymer concrete. Also, the developed geopolymer concrete using 100 % textile mercerizing water and the combined flyash-GGBS binder system showcases the highest post-fire residual strength and 48 % reduced water absorption. The cost of construction of geopolymer concrete was significantly reduced by 58.43 % and showed 10.28 % reduced carbon footprint due to the complete replacement of sodium hydroxide solution using textile mercerizing water. The findings of this research work will lead to the development of equivalent molar sustainable activator from the textile mercerizing water and the exploration of eco-friendly and durable geopolymer concrete in an affordable price. [Display omitted] • TMW waste as a 100 % alternative to commercial hydroxide activator. • Alkalinity and reactive metal ions of TMW induced the maximum strength of 46.9 MPa. • GF-TM100 % offered 48 % reduced rate of water absorption and better fire resistance. • Consumption of TMW showed 10.28 % lower carbon footprint than commercial activator. • 58.43 % reduced construction cost in GF-TM100 % geopolymer. [ABSTRACT FROM AUTHOR]

Terrestrial silicon (Si) from biogeochemically weathered rocks and soils into oceans must pass through several water bodies, resulting in some Si immobilized. Hence, the knowledge on Si distribution characteristics in different water bodies at a basin scale is helpful to understand Si immobilization. A total of 65 surface sediments and corresponding overlying water samples were sampled from six water bodies (Dianchi Lake, DL; Dadu River, DR; Tuojiang River, TR; Honghu Lake, HL; Donghu Lake, DhL; Taihu Lake, TL) in the Yangtze River Basin of China, total dissolved Si (TDSi) in overlying water and exchangeable Si (Ex-Si), active non-biogenic Si (NBSi), and total acid dissolved Si (TADSi) in sediments were analyzed. Water chemical parameters (pH, EC, and TDP) and sediment components (LOI, TN, TP, and TADFe) showed that the water environment characteristics of six water bodies differed. TDSi differed among regions and between lakes and rivers, significantly higher in water bodies in the upper reaches and rivers than the middle or lower reaches and lakes (p < 0.05), respectively. Ex-Si in sediments in the upper reaches was significantly higher than in the middle or lower reaches (p < 0.05), except for DhL, whose Ex-Si was the highest. Mean TADSi and active NBSi were significantly higher in lakes than rivers (p < 0.05). Oxidation of sediments significantly increased TDSi in overlying water and active NBSi in sediments (p < 0.01). Si forms in six water bodies significantly depended on components of the sediments (e.g. active Ca2+, Mg2+, Fe, and Al3+) and water chemical parameters (p < 0.05). Our results suggest that immobilization of Si in water bodies in the Yangtze River Basin depends on the types of water bodies and sediments, lakes and Fe–Al dominated sediments have a high potential to immobilize Si, but anthropogenic interference should not be ignored. • TDSi in overlying water in upper reaches was higher than middle or lower reaches. • Exchangeable Si in upper reaches sediments was higher than middle or lower reaches. • TADSi and active non-biogenic Si in sediments in lake were higher than river. • Ca–Mg-dominated sediments had lower capacity to immobilize Si than Fe–Al-dominated. [ABSTRACT FROM AUTHOR]

The deep utilization of green and renewable chemicals has laid the foundation for sustainable development. Recombining and modifying the long carbon chain structure and oxygen-containing functional groups in fats and oils can prepare important chemical products, such as high-quality second-generation biodiesel and oxygen-containing compounds (fatty alcohols, fatty acids, and esters). To improve the hydrodeoxygenation (HDO) performances of Ni-based catalysts, the effect of surface composition was studied in detail. Acid-base centers of Ni/γ-Al 2 O 3 catalysts were finely regulated by adding metal oxides (ZrO 2 , CeO 2 , La 2 O 3 , and MgO). It was found that enhancing the basicity of the studied catalyst was conducive to the methyl laurate conversion, but was not conducive to the HDO of oxygen-containing intermediates. In other words, the strong basicity would promote the condensation reaction of oxygen-containing intermediates over Ni-based catalyst. Among the studied catalysts, Ni/La 2 O 3 /γ-Al 2 O 3 catalyst showed the highest methyl laurate conversion (73%) and oxygen-containing product selectivity (64%) at 400 °C, LHSV = 1.5 h−1, H 2 /oil = 500 Nm3/m3, and P H2 = 2.0 MPa over the Ni/La 2 O 3 /γ-Al 2 O 3 catalyst. The acidity was favorable to improve the conversion of oils and the yield of alkane products, and the basicity was favorable to obtain oxygen-containing compounds over the corresponding catalysts. [Display omitted] • Acidic sites are favorable to improve the yield of alkane products. • Alkaline sites are favorable to obtain oxygen-containing compounds. • Highly dispersed Ni sites are conducive to activating H 2. • HDO products distribution can be adjusted by the acidity and alkaline. [ABSTRACT FROM AUTHOR]

Interest on the potential CO 2 sequestration of marine bivalve aquaculture has increased during the last decade. However, there is still some controversy about which biological processes are involved and how to estimate their contribution to the carbon footprint of bivalve aquaculture. This work considers the dissolved inorganic carbon, CO 2 and alkalinity fluxes linked to flesh and shell growth, calcification, respiration, faeces egestion, and ammonia excretion, accounting also for the RDOC production associated to these processes. We have developed an algorithm for a dynamic estimation of these fluxes based on a net production DEB growth model for mussels. The resulting model has been implemented in Python to create a toolbox with a graphical user interface. This toolbox allows the selection of different culture strategies, in terms of seeding date, seed size and culture length, and consequently analyzes the carbon footprint and impact on the carbonate chemistry of seawater of aquaculture management. • Mussel physiology is commonly ignored in carbon footprint estimates of mussel aquaculture. • MusselCF provides dynamic estimation of mussel culture carbon footprint and its impact on the seawater carbonate chemistry. • Hydrography, carbonate chemistry, seeding time and mussel seed and harvest size dictate the physiological carbon footprint. [ABSTRACT FROM AUTHOR]