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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]

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]

Leaf manganese (Mn) concentration has been used as a proxy for root exudation and phosphorus (P) uptake under controlled conditions, but there are limited field studies that confirm its validity. On an alkaline, P-poor soil, four lentil cultivars ('Samos', 'Thessaly', 'Flip', 'Algeria') received two P rates (0 and 26.2 kg P ha−1), for two growing seasons, to study whether aboveground assessments [leaf P, Mn, phenolic concentration (TPhe)] can approximate rhizosphere physiological traits related to P acquisition [soil acidification (ΔpH), arbuscular mycorrhizal fungi (AMF) colonisation, acid phosphatase activity (APase)]. Phosphorus addition had no effect on the determined traits. Cultivars differed in leaf P, Mn, TPhe and AMF, but there was no clear pattern relating aboveground traits to rhizosphere traits related to P acquisition, thus not confirming that leaf Mn can be a proxy of root exudation. Of three growth stages [V 7–8, R1 (first bloom), R4 (flat pod)], R1 seemed to be critical, showing the highest leaf P, ΔpH, AMF and TPhe. Precipitation and temperatures over the growing season were determinants of lentil responses affecting rhizosphere activity, soil P availability and finally leaf traits. In conclusion, in lentil on alkaline and P-limiting soils, high leaf Mn and phenolic concentration are not reliable indicators of rhizosphere P-acquiring mechanisms. In four lentil cultivars, under two phosphorus (P) levels (0 and 26.2 kg P ha−1), in an alkaline, P-poor soil, rhizosphere physiological traits related to P acquisition mechanisms and putative leaf proxies (P, manganese and phenolic concentration) were assessed. Our results indicated that the soil–root complexity in phosphorus acquisition mechanisms cannot be assessed by a single rhizosphere trait nor approximated by a single leaf trait. [ABSTRACT FROM AUTHOR]

The long‐term absorption by the oceans of atmospheric carbon dioxide is leading to the slow decline of ocean pH, a process termed ocean acidification (OA). The Arctic is a challenging region to gather enough data to examine the changes in carbonate chemistry over sufficient scales. However, algorithms that calculate carbonate chemistry parameters from more frequently measured parameters, such as temperature and salinity, can be used to fill in data gaps. Here, these published algorithms were evaluated against in situ measurements using different data input types (data from satellites or in situ re‐analysis climatologies) across the Arctic Ocean. With the lowest uncertainties in the Atlantic influenced Seas (AiS), where re‐analysis inputs achieved total alkalinity estimates with Root Mean Squared Deviation (RMSD) of 21 μmol kg−1 and a bias of 2 μmol kg−1 (n = 162) and dissolved inorganic carbon RMSD of 24 μmol kg−1 and bias of −14 μmol kg−1 (n = 262). AiS results using satellite observation inputs show similar bias but larger RMSD, although due to the shorter time span of available satellite observations, more contemporary in situ data would provide further assessment and improvement. Synoptic‐scale observations of surface water carbonate conditions in the Arctic are now possible to monitor OA, but targeted in situ data collection is needed to enable the full exploitation of satellite observation‐based approaches. Plain Language Summary: The long‐term absorption by the oceans of atmospheric carbon dioxide is leading to the slow decline of ocean pH, a process termed ocean acidification (OA). Sea surface salinity and temperature measurements from satellites or in situ re‐analysis products can be used as input to empirical algorithms to calculate OA parameters. This paper provides a first analysis of published Arctic Ocean empirical algorithms to estimate surface water OA parameters using observation‐based data sets. Results show promise in the Atlantic influenced Seas using both in situ re‐analysis and satellite products, but satellite salinity is relatively recent, and a paucity of in situ data in the satellite salinity era precludes a robust assessment. To fully exploit satellite‐based approaches, efforts need to focus on collecting in situ data while these satellites are overhead and operating in orbit. Key Points: Observation‐based data sets enable synoptic spatio‐temporal assessments of Arctic Ocean carbonate system parametersRe‐analysis and satellite products predict total alkalinity with accuracies of ∼21 μmol kg−1Targeted in situ data collection is needed to fully exploit satellite observations in the Arctic to enable carbonate system monitoring [ABSTRACT FROM AUTHOR]

The mining of favorable SNP loci and haplotypes is of great significance for the further cloning and molecular-assisted breeding of alkalinity-tolerance genes in rice. To improve the utilization rate of saline–alkaline lands and the yield of rice, we used the 1,322,884 SNPs obtained from the sequencing 173 of rice accessions in this study. Alkalinity-tolerance-related traits, including the germination energy (GE), germination rate (GR), seedling length (SL), root length (RL), relative alkaline damage rate (RADR) of the GERADR of the GR, RADR of the SL and RADR of the RL, were evaluated in 2019 and 2020 and revealed abundant phenotypes in the studied population. A genome-wide association analysis detected 10 quantitative trait loci (QTLs) related to alkalinity tolerance. In addition, a transcriptome sequencing analysis of the alkalinity-tolerant rice variety 'Yuedao 9' and the alkali-sensitive rice variety 'Tijin' under alkalinity stress and control conditions was performed. Three candidate genes that were predicted to be related to alkalinity tolerance in rice, namely LOC_Os06g06600, LOC_Os011g44680 and LOC_Os011g44600, were screened based on gene annotation, coding sequences and haplotype analysis. The results of this study provide important genetic information for the molecular improvement of rice. [ABSTRACT FROM AUTHOR]

Alkalinity stress is the main stress experienced by aquatic animals in saline–alkali water, which hinders the aquaculture development and the utilization of water resources. The two-factor (2 × 3) test was adopted to study the influence of dietary protein to carbohydrate ratios on the energy metabolism of Nile tilapia (Oreochromis niloticus) under different alkalinity stress levels. Three diets with different protein-carbohydrate ratios (P27/C35, P35/C25, and P42/C15) were fed to fish cultured in freshwater (FW, 1.3 mmol/L carbonate alkalinity) or alkaline water (AW, 35.7 mmol/L carbonate alkalinity) for 50 days. Ambient alkalinity decreased tilapia growth performance. Although ambient alkalinity caused oxidative stress and enhanced ion transport and ammonia metabolism in tilapia, tilapia fed the P27/C35 diet showed better adaptability than fish fed the other two diets in alkaline water. Further metabolomic analysis showed that tilapia upregulated all the pathways enriched in this study to cope with alkalinity stress. Under alkalinity stress, tilapia fed the P27/C35 diet exhibited enhanced pyruvate metabolism and purine metabolism compared with tilapia fed the P42/C15 diet. This study indicated that ambient alkalinity could significantly decrease growth performance and cause oxidative stress and osmotic regulation. However, reducing dietary protein content by increasing carbohydrates could weaken stress and improve growth performance, ion transport, and ammonia metabolism in tilapia under long-term hyperalkaline exposure. [ABSTRACT FROM AUTHOR]

Context: Under natural field conditions, plants confront the co-occurrence of stresses. A comprehensive insight into combined-stress tolerance is requisite to developing stress resilience in cultivars of oats (Avena sativa L.) for saline–alkaline soil. Aims: This study was undertaken to characterise diverse oat genotypes for seedling growth attributes under two saline and alkaline concentrations and under combined saline–alkaline conditions. Methods: We screened 105 accessions of the genus Avena with the following treatments: control, reverse osmosis water; moderate salinity (50 mM); high salinity (100 mM); moderate alkalinity (15 mM); high alkalinity (30 mM); combined moderate salinity–alkalinity (50 mM + 15 mM); and combined high salinity–alkalinity (100 mM + 30 mM). For saline treatments, NaCl and Na2SO4 salts were used in equimolar concentrations, and for alkaline treatments, NaHCO3 and Na2CO3. Key results: Analysis of variance showed significant (P ≤ 0.001) variation among treatments and genotypes. Principal component analysis revealed 83.3% of the total genetic variation accounted for in the first two principal components. Correlation analysis showed a significant positive correlation between final germination percentage and seedling vigour index. Stress tolerance index identified tolerant and sensitive oat genotypes under high saline and alkaline stress, and multi-trait stability analysis confirmed the stability of performance of some genotypes under the imposed treatments. Conclusions: According to the stress tolerance index and multi-trait stability analysis, genotypes IG-20-477, OS-377, IG-20-798 and IG-20-575 were found suitable for high saline–alkaline stress. Implications: The identified tolerant oat genotypes can be used as donors for the development of stress-resilient oat cultivars, and for generating mapping populations in oat. Saline–alkaline soil is a global threat to crop production, and the combined effects of salinity and alkalinity may be greater than individual effects, with seed germination the most sensitive stage to these stresses. We evaluated oat germplasm under combined stress in order to identify and select lines with better seed germination and high vigour. The stress-tolerant lines identified could serve as base material for stress-tolerance breeding programs. [ABSTRACT FROM AUTHOR]

As suggested by the Water Framework Directive (WFD), in order to determine the ecological status of the rivers, it is necessary to define the reference conditions that can be compared with observed conditions. In this study, selected candidate 17 rivers of the Akarçay Basin (Türkiye) were sampled three times in 2018, and their ecological status was evaluated using 18 different diatom indices. 10 different environmental variables were also sampled combined with diatoms, and alkalinity and total organic carbon were determined as the most crucial pressures for the distribution of diatom assemblages based on the Redundancy Analysis (RDA). Among the diatom indices, Steinberg and Schiefele's Index (SHE), Rott's Saprobic Index (ROTTs), Metric-European Index (CEE), Rott's Trophic Index (ROTTt), Watanabe Index (WAT) and Swiss Diatom Index (DICH) showed significant correlations with alkalinity and total organic carbon according to Multiple Linear Regression (MLR) results. SHE and ROTTs indices showed higher and similar responses to the pressures, and indicated high and good ecological status for sampling sites. Sampling sites with high ecological status can be evaluated in the reference monitoring network for future studies in the Akarçay Basin. [ABSTRACT FROM AUTHOR]

Due to increasing atmospheric CO2, algal growth systems at high pH are of interest to support enhanced diffusion and carbon capture. Given the interactions between algal growth, pH, and alkalinity, data from Watson and Drapcho (2016) were re-examined to determine the impact of the non-carbonate constituents in BG11 media on estimates of Monod kinetic parameters, biomass yield, and cell stoichiometry. Based on a computational method, non-carbonate alkalinity (NCA) in BG11 media varies with pH according to: NCA (meq/L) = 0.0393×e0.2075×pH + (2.086×10-9)e1.860×pH (R² = 0.999) over the pH range of 10.3 -- 11.5. Updated maximum specific growth rates were determined to be 0.060, 0.057, and 0.051 hr-1 for CO2, HCO3, and CO3, respectively. Generalizable stoichiometric algal growth equations that consider variable nutrient ratios and multiple inorganic carbon species were developed. Improved kinetic and stoichiometric parameters will serve as the foundation for a dynamic mathematical model to support the design of high pH algal carbon capture systems. [ABSTRACT FROM AUTHOR]

Recycled aggregates, especially the fine (0–4 mm) fraction, are often contaminated with sulfates coming from gypsum residues on demolition sites. When these aggregates are used in concrete, the sulfates can induce internal sulfate attack which causes expansion of the concrete. European standard EN 206:2013 sets the water-soluble sulfate limit at 0.2% by weight of the aggregate, but other studies suggest this limit could be safely increased. In addition to the sulfate content, other parameters, such as the porosity and alkalinity of the mix, have been shown to influence the swelling results. In this study, different proposed sulfate limits were evaluated on concrete made with 100% fine recycled aggregates (FRA). It was also researched whether the mixing parameters could change the swelling amount regardless of the sulfate content. The results showed that the incorporation of FRA with sulfate contents up to 0.8 wt% is safe when combined with coarse natural aggregates. If coarse recycled aggregates are used in the mix, the sulfate content of FRA can be up to 0.3%. The swelling caused by these sulfate levels was not high enough to be influenced by the porosity or alkalinity of the mix. [ABSTRACT FROM AUTHOR]

Mango is a fruit consumed worldwide, but generates wastes, which have potential to be valorised, because they possess compounds with demonstrated positive implications for the consumer's health. For this reason, in the present study, biscuits with mango pulp and powders developed from its wastes were developed. The chemical composition was determined for the mango peel, pulp, and seed according to AOAC procedures, but also for the mango biscuit and a reference. The total phenolic content (TPC) was assessed with the Folin-Ciocâlteu method, while the antioxidant potential was tested using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Titratable acidity and alkalinity were also determined. The textural and colour parameters of the mango-based biscuit were compared with those of a reference. The newly developed product was rich in proteins (7.26%), due to the inclusion of mango peel and seed powders, and presented increased fat content. The mango-based biscuit registered a TPC of 123.90 mg GAE/100 g, while the seed had a higher TPC of 3893.33 mg GAE/100 g. High antioxidant potential was determined for the mango waste ingredients (94.76% RSA DPPH inhibited for the seed and 93.9% RSA DPPH inhibited for the peel), but for the mango-based biscuit the antioxidant potential was lower. The hardness of the mango biscuit was high and the colour was different from that of the reference; thus, more studies regarding an optimal formulation are still necessary. [ABSTRACT FROM AUTHOR]

The object of research is the black liquor of the alkaline pulping sample Paulownia Clone in Vitro 112® with active alkali consumption of 14, 18 and 22 % in Na2O units from the mass of completely dry raw materials. The problem solved in the work is related to the formation of waste in the form of black liquor during pulp production. It is noted that as a result of the production of 1 ton of cellulose, up to 7 tons of black liquor is formed. In the course of the work, an analysis of the total titrated and active alkalinity in the white and black liquor after cooking paulownia wood was carried out, and the pH value was determined. The dependence of the content of dry substances in black liquor on the consumption of active alkali, the duration of cooking, the presence of a catalyst, and the final temperature of the delignification process is given. The amount of organic and mineral components of dry substances of black liquor per 1 ton of air-dry fibrous semi-finished products was calculated. It was established that with an increase in temperature by 20 °C (from 150 to 170 °C) and a duration of approximately 1.5 times (from 60 to 90 min and from 90 to 150 min), with the same consumption of active alkali and the use of a catalyst in the conditions after sodium pulping, the content of dry substances in the black liquor increases by 1.5–3 %. This regularity is explained by the transition into the solution of a greater number of dissolution products of lignin, hemicelluloses, and mineral substances. Estimated values for the content of mineral and organic substances in black liquor after cooking paulownia wood for a duration of 150 min and a final temperature of 170 °C at different consumptions of active alkali and the use of catalysts in the form of anthraquinone and ethyl alcohol are within the range of 1024–1518 kg per 1 ton dry pulps of normal yield and can be used in practice. The obtained results can be used to form an assessment of the black liquor as an additional resource potential for the economy of production. [ABSTRACT FROM AUTHOR]

The success of shrimp cultivation is assessed based on the resulting performance, survival, growth, and total shrimp production. Apart from parent quality and feed quality, water quality is a determining factor in the success of shrimp cultivation. Good water quality will increase cultivation productivity. The research aims to measure the performance of vannamei shrimp using an intensive cultivation system at PT Bumi Cimandala Lestari by paying attention to the quality of cultivation waters. This research uses a descriptive method by following the entire series of cultivation production in the Bumi Cimandala Lestari shrimp pond. The activity lasts three months, from August to November 2022 at PT. Bumi Cimandala Lestari is located at Kp. Cipeundeuy, Surade Village, Sukabumi Regency. The results showed that the average survival rate from 8 cultivation ponds reached 67% with a growth rate of 0.26 g/day. The total production obtained was 55.42 tons with a size of 70-100 fish/kg. Water quality during the study was within the optimal range. The pH value of the water ranges from 7-9 with salinity ranging from 18.1 – 20.4 ppt. Dissolved oxygen value > 5 mg/L, and alkalinity ranges from 122 – 183 mg/L. The research showed that cultivation ponds had a temperature range between 24.8-30.4 and DO ranging from 2.49-8.23 mg/L. Water quality conditions are thought to support the growth and survival of shrimp well. [ABSTRACT FROM AUTHOR]

The development of eel fish cultivation has quite good business opportunities and prospects. However, the main obstacle in cultivating eel fish is the high mortality in the glass eel phase, so it has a survival rate of 30-50% and slow growth, namely less than 3.1%. One effort to maximize glass eel maintenance is through optimizing alkalinity as a buffer for water quality. The alkalinity level in the maintenance medium can be regulated by adding calcium carbonate (CaCO3). This research aims to determine the effect of adding CaCO3 to the rearing media on glass eels' growth and survival rate. The study was conducted for 14 days in March 2023. The method was wholly randomized with three replications in 3 treatments (P1=0 mg L-1, P2=50 mg L-1, P3=100 mg L-1). Analysis of research data used the ANOVA test. Adding CaCO3 produced a natural effect on length growth with a value of 0.16 cm, weight growth of 0.73 mg L-1, and a survival rate of 74%. The treatment did not naturally affect the alkalinity levels in the glass eel maintenance media. The best treatment effect was found in P2 (50 mg L-1). These results show that adding CaCO3 to the glass eel-rearing media decreased but did not naturally affect alkalinity levels. [ABSTRACT FROM AUTHOR]

Carrageenan is a marine biopolymer that can be extracted from cell wall of some red carrageenophyte. In this study, response surface methodology was used to investigate the procedure of carrageenan melting point and gelling temperature from Hypnea flagelliformis. Independent variables, alkalinity concentration (0.25-2%), extraction temperature 70-90 °C) and extraction time (60-240 minutes) were applied in five levels. Base on the result, effects of all independent variables on melting point were significant (P<0.05). The NaOH concentration had a significant effect on gelling temperature (P>0.05). Polynomial models developed for the melting point and gelling. Optimum data for independent variables were alkalinity concentration 1.54%, temperature 85 °C and time 203 minutes. Confirmatory test was earned as follows melting point 63.8 ±0.91 °C and gelling temperature 37.29 ±0.62 °C. The experimental data and model forecasting were similar (P>0.05). [ABSTRACT FROM AUTHOR]

Coastal ocean acidification is a worldwide problem associated with anthropogenic activity and climate change. In this study, a close relationship between submarine groundwater discharge (SGD) and coastal ocean acidification in Hong Kong's coastal waters is discovered. We for the first time evaluated the direct influence of SGD on seawater pH decline. Results show that SGD can contribute to up to 48% of seawater pH variation among terrestrial water input, air‐sea CO2 exchange, photosynthesis/respiration, and bay‐open water exchange in semi‐closed bays through direct input of carbonate species. Local air‐sea CO2 exchange has negligible influences on the seawater pH. In the semi‐closed bay areas, SGD and aerobic respiration are major contributors to seawater pH variation but in areas with open space, the exchange process with open waters is more important. In addition to the direct input of carbonate species (total alkalinity and dissolved inorganic carbon), SGD also influences the seawater pH via considerable nutrient loadings. The findings highlight the importance of the investigation and management of groundwater to alleviate the fast coastal ocean acidification. Plain Language Summary: Seawater becoming more acidic is a big problem in coastal areas around the world due to climate change. The main causes of this acidification are excessive nutrient release and human‐generated carbon dioxide. When groundwater flows into coastal areas, it carries chemicals from the land that can affect the pH of the seawater. In our research, we discovered that groundwater releases more dissolved inorganic carbon compounds, which lower the seawater's pH, compared to the total alkalinity that normally helps maintain a stable pH. Groundwater is a major factor in causing acidification in semi‐closed bays along the coast. We want to emphasize the importance of understanding the impact of coastal processes and managing groundwater in order to slow down the acidification of coastal waters. Key Points: Submarine groundwater discharge (SGD) strongly correlates with long‐term ocean acidification rates, unveiling their significant relationshipSGD accounts for ∼50% of seawater pH decline in semi‐closed bays, primarily through direct carbonate species inputSGD indirectly impacts seawater pH decline by influencing aerobic respiration processes, amplifying its role in pH dynamics [ABSTRACT FROM AUTHOR]

The pacific white shrimp (Litopenaeus vannamei) is now a more common aquaculture species in saline-alkali waters, while alkalinity stress is considered to be one of the stressors for shrimp. Thus, an understanding of the molecular response to alkalinity stress is critical for advancing the sustainability of culture in pacific white shrimp. In this study, we aimed to explore the response mechanism to acute high-alkaline stress by RNA-seq at low-alkaline (50 mg/L) and high-alkaline (350 mg/L). We identified 215 differentially expressed mRNAs (DEGs) and 35 differentially expressed miRNAs (DEMs), of which 180 DEGs and 28 DEMs were up-regulated, 35 DEGs and 7 DEMs were down-regulated, respectively. The DEGs were enriched in several pathways, including carbohydrate digestion and absorption, pancreatic secretion, starch and sucrose metabolism, antigen processing and presentation and glutathione metabolism. The DEMs involved in lysosome and ion transport related pathways were significantly up-regulated. We also achieved 42 DEGs, which were targeted by DEMs. miRNA-mRNA regulatory network was constructed by integrated analysis of miRNA-mRNA data. We detected several genes and miRNAs which were identified as candidate regulators of alkalinity stress, and expression patterns of key genes related to alkalinity stress in pacific white shrimp. Among these genes, the expression levels of most key genes enriched in ion regulation, digestion and immunity were increased, and the expression levels of genes enriched in metabolism were down-regulated. This research indicated that the homeostatic regulation and digestion changed significantly under acute alkaline stress, and the variations from metabolic and immunity can cope with the osmotic shock of alkalinity stress in pacific white shrimp. This study provides key clues for exploring the molecular mechanism of pacific white shrimp under acute alkalinity stress, and also gives scientific basis for the optimisation of saline-alkaline aquaculture technology. [ABSTRACT FROM AUTHOR]

Total alkalinity (AT) and total dissolved inorganic carbon (CT) in the oceans are important properties to understand the ocean carbon cycle and its link with climate change (ocean carbon sinks and sources) or global change (ocean acidification). We present a data-base of more than 44 400 AT and CT observations in various ocean regions obtained since 1993 mainly in the frame of French projects. This includes both surface and water columns data acquired in open oceans, coastal zones and in the Mediterranean Sea and either from time-series or punctual 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 µmol kg-1 for both AT and CT. Given the lack of observations in the Indian and Southern Oceans, we added sea surface underway AT and CT data obtained in 1998-2018 in the frame of OISO cruises and in 2019 during the CLIM-EPARSES cruise measured onboard using the same technique. Separate datasets for the global ocean, and for the Mediterranean Sea are provided in a single format (https://doi.org/10.17882/95414, Metzl et al., 2023) that offers a direct use for regional or global purposes, e.g. AT/Salinity relationships, long-term CT estimates, constraint and validation of diagnostics CT-AT reconstructed fields or ocean carbon and coupled climate/carbon models simulations, as well as data derived from BG-ARGO floats. When associated with other properties, these data can also be used to calculate pH, fugacity of CO2 (fCO2) and other carbon systems properties to derive ocean acidification rates or air-sea CO2 fluxes. [ABSTRACT FROM AUTHOR]

Electrochemical CO2 reduction reaction (CO2RR) provides a promising approach for sustainable chemical fuel production of carbon neutrality. Neutral and alkaline electrolytes are predominantly employed in the current electrolysis system, but with striking drawbacks of (bi)carbonate (CO32−/HCO3−) formation and crossover due to the rapid and thermodynamically favourable reaction between hydroxide (OH−) with CO2, resulting in low carbon utilization efficiency and short‐lived catalysis. Very recently, CO2RR in acidic media can effectively address the (bi)carbonate issue; however, the competing hydrogen evolution reaction (HER) is more kinetically favourable in acidic electrolytes, which dramatically reduces CO2 conversion efficiency. Thus, it is a big challenge to effectively suppress HER and accelerate acidic CO2RR. In this review, we begin by summarizing the recent progress of acidic CO2 electrolysis, discussing the key factors limiting the application of acidic electrolytes. We then systematically discuss addressing strategies for acidic CO2 electrolysis, including electrolyte microenvironment modulation, alkali cations adjusting, surface/interface functionalization, nanoconfinement structural design, and novel electrolyzer exploitation. Finally, the new challenges and perspectives of acidic CO2 electrolysis are suggested. We believe this timely review can arouse researchers′ attention to CO2 crossover, inspire new insights to solve the "alkalinity problem" and enable CO2RR as a more sustainable technology. [ABSTRACT FROM AUTHOR]

Carbon nanotubes are a new type of material with excellent properties, and their incorporation into cementitious materials can improve the microstructure and durability of the material. This paper reviews the research progress on the effect of nucleation, filling and bridging properties of carbon nanotubes on the microstructure and carbonation resistance of cementitious materials, and discusses the mechanism of the effect of the doping amount, dispersion method and length-to-diameter ratio of carbon nanotubes on the carbonation reaction of cementitious materials. The analysis shows that carbon nanotubes promote the hydration of cement by nucleation, increase the hydration product Ca(OH)2, increase the alkalinity of the matrix and slow down the carbonisation, and optimise the pore structure of the material and the compactness of the interfacial transition zone by combining the filling and bridging effects, inhibit the formation of microcracks and prevent the infiltration of CO2, thus optimising the microstructure of cement-based materials and enhancing their anti-carbonisation properties. Finally, the problems of the current research are analyzed and the prospects of its research are given. [ABSTRACT FROM AUTHOR]

Quinoa (Chenopodium quinoa Willd.) is a dicotyledonous cereal that is rich in nutrients. This important crop has been shown to have significant tolerance to abiotic stresses such as salinization and drought. Understanding the underlying mechanism of stress response in quinoa would be a significant advantage for breeding crops with stress tolerance. Here, we treated the low-altitude quinoa cultivar CM499 with either NaCl (200 mM), Na2CO3/NaHCO3 (100 mM, pH 9.0) or PEG6000 (10%) to induce salinity, alkalinity and hypertonia, respectively, and analyzed the subsequent expression of genes and small RNAs via high-throughput sequencing. A list of known/novel genes were identified in quinoa, and the ones responding to different stresses were selected. The known/novel quinoa miRNAs were also identified, and the target genes of the stress response ones were predicted. Both the differently expressed genes and the targets of differently expressed miRNAs were found to be enriched for reactive oxygen species homeostasis, hormone signaling, cell wall synthesis, transcription factors and some other factors. Furthermore, we detected changes in reactive oxygen species accumulation, hormone (auxin and ethylene) responses and hemicellulose synthesis in quinoa seedlings treated with stresses, indicating their important roles in the response to saline, alkaline or hyperosmotic stresses in quinoa. Thus, our work provides useful information for understanding the mechanism of abiotic stress responses in quinoa, which would provide clues for improving breeding for quinoa and other crops. [ABSTRACT FROM AUTHOR]

Ocean acidification is likely to impact all stages of the ocean carbonate pump, i.e. the production, export, dissolution and burial of biogenic CaCO3. However, the associated feedbacks on anthropogenic carbon uptake and ocean acidification have received little attention. It has previously been shown that Earth system model (ESM) carbonate pump parameterizations can affect and drive biases in the representation of ocean alkalinity, which is critical to the uptake of atmospheric carbon and provides buffering capacity towards associated acidification. In the sixth phase of the Coupled Model Intercomparison Project (CMIP6), we show divergent responses of CaCO3 export at 100 m this century, with anomalies by 2100 ranging from -74% to +23% under a high-emissions scenario. The greatest export declines are projected by ESMs that consider pelagic CaCO3 production to depend on the local calcite/aragonite saturation state. Despite the potential effects of other processes on alkalinity, there is a robust negative correlation between anomalies in CaCO3 export and salinity-normalized surface alkalinity across the CMIP6 ensemble. Motivated by this relationship and the uncertainty in CaCO3 export projections across ESMs, we perform idealized simulations with an ocean biogeochemical model and confirm a limited impact of carbonate pump anomalies on twenty-first century ocean carbon uptake and acidification. However between 2100 and 2300, we highlight a potentially abrupt shift in the dissolution of CaCO3 from deep to subsurface waters when the global scale mean calcite saturation state reaches about 1.23 at 500 m (likely when atmospheric CO2 reaches 900 to 1100 ppm). During this shift, upper ocean acidification due to anthropogenic carbon uptake induces deep ocean acidification driven by a substantial reduction in CaCO3 deep dissolution following its decreased export at depth. Although the effect of a diminished carbonate pump on global ocean carbon uptake and surface ocean acidification remains limited until 2300, it can have a large impact on regional air-sea carbon fluxes, particularly in the Southern Ocean. [ABSTRACT FROM AUTHOR]

A low-cost, automated pipetting system (auto pipet) was developed to deliver microliter volumes of aqueous solutions. This system was constructed using a single board computer, 3 D-printed parts, stepper motors, and other commercially available components. The performance of the auto pipet was found to be comparable or better than manual pipetting and a commercially available liquid handling system. Inter-day, intra-day, inter-instrumental, and intra-instrumental validation studies were performed to evaluate the accuracy and precision of liquid delivery using the auto pipet. Accuracy was determined to be from 98 to 102% with the precision, represented as the relative standard deviation, to be less than 3%. The auto pipet was further evaluated by the preparation of calibration and check standards for the determination of method detection limit, accuracy, and precision for trihalomethanes using a commercially available monitoring system. The auto pipet was also used as a digital buret to perform water hardness and water alkalinity titrations with promising results. [ABSTRACT FROM AUTHOR]