Silicate Concentrations Research Articles

Investigating the feasibility of producing sustainable and compatible binder using marble waste, fly ash, and rice husk ash: A comprehensive research for material characteristics and production

This research aims to develop a new marble-based binding material for evaluating its strength blended with rise husk ash and fly ash. Newly developed marble-based cement was prepared by burning waste marble powder and clay. The marble cement was then blended separately with varying amounts of fly ash (20, 30, and 40% by mass of marble cement) and rice husk ash (20, 30, and 40% by mass of marble cement) to find the most suitable combination for mortar in terms of strength gain. The mortar specimens were subjected to various load tests, including compressive and flexural strength, and also to various morphology and microstructural tests including X-Ray diffraction, thermo-gravimetric, and scanning electron microscopy analyses. According to the results, the compressive strength of the marble cement mortar was less than ordinary Portland cement mortar but greater than the M1 mortar (5 MPa, minimum compressive strength of mortar for brick masonry) as per the Building Code of Pakistan 2007 (BCP:2007) and Indian Standards (IS:1905). Blended marble cement mortars displayed improved strengths, yet the early strength of blended mortars was lower than Portland cement mortar due to higher di-calcium silicate content and slow pozzolanic activity, but the later-age strength of mortar prepared with the marble cement blended with 30% rice husk ash was found marginally higher than the ordinary Portland cement mortar. Moreover, incorporating marble waste, rice husk ash, and fly ash as binding materials to manufacture building materials will encourage sustainable growth by reducing environmental issues associated with their disposal.

Spatial heterogeneity in water quality across the northern nearshore regions of the Laurentian Great Lakes

We provide the first comprehensive analysis of spatial heterogeneity in water quality across the Canadian nearshore regions of the Laurentian Great Lakes (LGL) with periodic sampling in the ice-free seasons from 2000 to 2019 for 24 water quality variables from 52 nearshore sites. We asked: (1) What is the extent, range, and magnitude of spatial heterogeneity in water quality conditions across the nearshore of the Canadian Great Lakes? and (2) How do features of anthropogenic development, sub-basin characteristics, anticipated coastal circulation, and weather influence water quality conditions in the nearshore of the Canadian Great Lakes? Principal Components Analysis explained 42% of the variation in water quality across the Canadian Great Lakes, with high spatial heterogeneity both within and among lakes, ranging from oligotrophic conditions in Lake Superior to eutrophic conditions in Lake Erie. Lakes Erie and Ontario generally had higher concentrations of chloride, chlorophyll a, and nutrients while higher silicate concentrations were observed in Lake Superior. Consistent patterns of degraded water quality were observed in Areas of Concern, such as Hamilton Harbour, Bay of Quinte, Nipigon Bay, and near Thunder Bay. Across the nearshore of the Canadian Great Lakes, regions with warmer air temperatures, in addition to urbanized and agricultural landscapes, were associated with deteriorated water quality. Our study highlights the importance of improving management practices across urban and agricultural landscapes, particularly in consideration of climatic change cumulatively degrading water quality conditions in the highly biologically, culturally, and socioeconomically important nearshore regions of the LGL.

Seasonality of phytoplankton growth limitation by iron and manganese in subantarctic waters

Phytoplankton indirectly influence climate through their role in the ocean biological carbon pump. In the Southern Ocean, the subantarctic zone represents an important carbon sink, yet variables limiting phytoplankton growth are not fully constrained. Using three shipboard bioassay experiments on three separate voyages, we evaluated the seasonality of iron (Fe) and manganese (Mn) co-limitation of subantarctic phytoplankton growth south of Tasmania, Australia. We observed a strong seasonal variation in a phytoplankton Fe limitation signal, with a summer experiment showing the greatest response to Fe additions. An autumn experiment suggested that other factors co-limited phytoplankton growth, likely low silicic acid concentrations. The phytoplankton responses to Mn additions were subtle and readily masked by the responses to Fe. Using flow cytometry, we observed that Mn may influence the growth of some small phytoplankton taxa in late summer/autumn, when they represent an important part of the phytoplankton community. In addition, Mn induced changes in the bulk photophysiology signal of the spring community. These results suggest that the importance of Mn may vary seasonally, and that its control on phytoplankton growth may be associated with specific taxa.

Experimental study of improved cement silicate grouting material for broken surrounding rock

The broken surrounding rock seriously affects the safety production of coal mines. This paper design the orthogonal experiment of fly ash-cement-silicate grouting material and the activation experiment of fly ash to obtain the proportion of the cement silicate grouting material and the activation conditions of fly ash to meet the requirements for supporting the broken surrounding rock. The influence law of water-content ratio, fly ash content, silicate concentration and silicate content on the setting time and strength of cement silicate grouting materials are studied, the influence law of activator content and activation time on the activation performance of fly ash are compared and analyzed. The study of this paper elucidates the hydration reaction mechanism of cement silicate grouting material and the activation mechanism of fly ash. It solves the problems of unreasonable grouting material proportion, unclear activation conditions of fly ash, and difficulty in supporting the broken surrounding rock. The influence law of activator content and activation time on the network structure of grouting materials are obtained. The proportion of grouting materials meeting the requirements is the water-cement ratio of 0.8, fly ash content of 30%, silicate concentration of 40 Be’ and silicate content of 25%, the most optimum activation conditions are that activation time is 2h and activator content is 3%. The influence of cement silicate grouting material on the support effect of broken surrounding rock is obtained, the displacement of the roadway's sides and roadway's roof using grouting materials is 40% and 36% less than that of roadway's sides and roadway's roof without grouting material. The significance of this paper is to deeply analyze the effects of water-cement ratio, fly ash content, silicate concentration and silicate content on the setting time and strength of cement silicate grouting materials and obtain the effects of activator content and activation time on the activation effect of fly ash. Applying the proportion of the cement silicate grouting material and the activation conditions of fly ash in engineering practice has achieved good results, which can increase the stability of broken surrounding rock and effectively control surrounding rock deformation.

Drastic changes in a lower-trophic-level ecosystem attributed to unprecedented harmful algal outbreaks in 2021 on the Pacific shelf off southeast Hokkaido, Japan

Unprecedented, large-scale harmful algal blooms (HABs) occurred in Pacific coastal shelf waters off the southeastern coast of Hokkaido, Japan, in the autumn of 2021. To understand how these HABs, composed primarily of Karenia selliformis, changed the structures of lower-trophic-level ecosystems in shelf waters, we analyzed high-resolution in situ ship measurements taken during October 2015–2021. We mainly compared physico-biochemical variables averaged over the shelf in 2021 and in 2015–2020. Chlorophyll-a concentrations at a depth of 10 m were approximately 2.3-fold higher in 2021 than in 2015–2020. Chlorophyll-a concentrations were highest at the sea surface in 2021, and vertically integrated concentrations were 1.8-fold higher in 2021 than in 2015–2020. Silicate concentrations at a depth of 10 m were higher in 2021, whereas nitrate and phosphate concentrations were largely the same. Abundances of major diatoms and picophytoplankton (e.g., Synechococcus spp.) at a depth of 10 m declined by 2 orders and 1 order of magnitude in 2021, respectively, whereas Karenia spp. abundance greatly increased. These results indicated that outbreaks of K. selliformis suppressed the growth of other algal species and dramatically changed nutrient flows and balances in the coastal shelf ecosystem. The suppression of non-Karenia algal species might have occurred through interspecific competition for nutrients as well as allelopathy and/or mixotrophy by K. selliformis.

The characterization of Pahae Natural Zeolite and its application on ammonium removal

A study was conducted to determine the morphology and structure of Natural Zeolite obtained from Pahae, Tapanuli Utara, Indonesia. The results of X-ray diffraction (XRD) analysis revealed that the zeolite contained primarily mordenite and clinoptilolite crystals. Fourier Transform Infrared (FTIR) spectroscopy indicated the presence of TO4 ([SiO4]−4 and [AlO4]−5 groups), which appeared at a wavenumber of 1045.42 cm−1 and shifted to 1037.30 cm−1 after the hydrothermal process. Furthermore, porosity testing demonstrated that the samples exhibited higher porosity values with increasing hydrothermal temperature, leading to enhanced water adsorption. Chemical composition analysis using X-ray fluorescence (XRF) revealed an increase in silicate content from Pahae Natural Zeolite (PNZ) to Pahae Natural Zeolite–Hydrothermal Activated (PNZ-HA).

Alkali Activation of Solid Waste from Cable Wire Manufacturing Industry for Building and Construction

Iron-laden tailings have received a lot of attention in recent years, especially for their potential use in civil engineering projects. Alkaline activation was studied as a method to use iron sludge from cable wire manufacturing industry (CWI). Two reagents, namely sodium silicate and sodium hydroxide concentrations of 1 M, 5 M, and 10 M were studied for alkaline activation. To make a paste, the solutions were combined with CWI waste. Using 50x50x50 mm3 molds, the paste was cast into triplicates and allowed to set. The molds were demolished once the paste had solidified, and the specimens were cured at increased temperatures and at room temperature. The specimens were cured for days, 7 days, and 14 days at ambient temperature. The specimens were subjected to geochemical and geotechnical testing after the curing period to determine the mechanism that contributed to unconfined compressive strength (UCS) development. The findings demonstrated that when the two reagents were compared, sodium hydroxide proved to be a better activator, resulting in a greater unconfined compressive strength, particularly when the specimen was cured at a high temperature. When cured at both elevated and ambient temperatures, the sodium silicate did not perform well as an activator, as the specimen were not durable.

Study on improvement of waterproofing performance of CCCW with silicone waterproof material and waterbased capillary inorganic waterproofer

The silicone waterproof material and waterbased capillary inorganic waterproofer possess the advantages of rapid film formation and significant hydrophobic effect. In this study, the material composition and mixing ratio of the silicone waterproofing material and waterbased capillary inorganic waterproofing were investigated by multiple performance tests. The results indicated that a white coating was formed on the surface when the mixing ratio of isobutyl-triethoxy-silane and isooctyl-triethoxy-silane was more than 69 %. When the content of sodium and potassium methyl silicate exceeded 0.5 %, respectively, there was an upward trend of contact angle while the reduction in water absorption gradually decreased. Meanwhile, the contact angle and water absorption height of silicone waterproof material were tested. The results showed that the coating performance and hydrophobicity were the best when the mixing ratio of isobutyl-triethoxy-silane, isooctyl-triethoxy-silane, sodium methyl silicate, and potassium methyl silicate was 1.5:0.2:1:0.5. When the matrix mortar specimen was made of Cementitious Capillary Crystalline Waterproofing Materials (CCCW), the lowest water absorption height and water absorption of the experimental group consisted of sodium silicate, sodium tetraborate, sodium phosphate, and sodium hydroxyethyl cellulose were 316.7 % and 39%, respectively. The lowest water absorption height and water absorption of the experimental group consisted of sodium silicate, sodium tetraborate, nano-silica, and sodium hydroxyethyl cellulose were 215.4 % and 28 %, respectively. The results showed that CCCW combined with the experimental group consisted of sodium silicate, sodium tetraborate, sodium phosphate, and sodium hydroxyethyl cellulose had better waterproofing effect.

Geochemical Characteristics of the Upper Permian Longtan Formation from Northeastern Sichuan Basin: Implications for the Depositional Environment and Organic Matter Enrichment

AbstractA set of organic‐rich shales of the upper Permian Longtan Formation, which is widely developed in the northeastern part of the Sichuan Basin, is a key formation for the next step of exploration and development. At present, most studies on this set of formations have focused on the reservoir characteristics and reservoir formation mechanism of the shales, and basic studies on the palaeoenvironment and organic matter (OM) enrichment mechanism have not been fully carried out. In this paper, we recovered the sedimentary palaeoenvironment by mineralogical, elemental geochemical and organic geochemical analyses, and explored the enrichment mechanism of OM under the constraints of palaeoenvironmental evolution. The shales can be divided into two stages of sedimentary evolution: compared with the shales of the Lower Longtan Formation, the shales of the Upper Longtan Formation are relatively rich in quartz, poor in clay and carbonate minerals, and the OM type changes from type III to type II2. The depositional environment has undergone a change from sea level rise, from warm and wet climate to dry and cold climate, and from oxygen‐poor condition restricted to open reduction environment; the land source input has decreased, the siliceous mineral content has increased, the biological productivity has improved, and the deposition rate has changed from high to low. A depositional model was established for the shales of the Longtan Formation, reflecting the differential reservoir formation pattern of organic matter. For the Lower Longtan Formation shales, the most important factors controlling OM content are terrestrial source input and deposition rate, followed by paleoclimate and paleo‐oxygen conditions. For the Upper Longtan Formation shales, the most important controlling factor is paleoproductivity, followed by sedimentation rate. The depositional model constructed for the Upper and Lower Longtan Formation shales can reproduce the enrichment of organic matter and provide a basis for later exploration and development.

Carbonation and freeze-thaw resistance of geopolymer-zeolite cementitious composites

Geopolymer-zeolite cementitious composites (GZCC) are emerging materials which can find applications as self-supported cementitious adsorbents, self-cleaning composite panels, etc. Considering the carbonation and free-thaw attack tendency of GZCC, this study assessed the carbonation and freeze–thaw resistance of geopolymer-zeolite cementitious composites (GZCC). GZCC samples with different activator-to-binder ratios (0.8 or 1), activator composition (sodium silicate-to NaOH ratio of 0.17 or 0.5 and NaOH molarity of 5 or 8 M), and hydrothermal duration (24 or 48 h), were prepared. Samples were exposed to accelerated carbonation environment after 3 and 14 days of curing. The physical and chemical characteristics of samples before and after carbonation were assessed by means of compressive strength, x-ray diffraction (XRD), and mercury intrusion porosimetry (MIP). Free-thaw exposure was started after 14 days of initial curing. Samples were put at -20 °C during freezing and immersed in water during thawing. The test results revealed that the carbonation resistance of samples was dependent on the mix proportion. A higher activator and lower silicate content resulted in lower residual strength which can be related to the higher porosity and lower compressive strength values of reference uncarbonated samples. However, zeolitic phases were still present which directs that the functionality of GZCC might not be affected much. All the samples broke after freeze–thaw exposure between 2 to 20 cycles. The formation of zeolitic crystals enhanced the open porosity of GZCC samples which caused their poor freeze–thaw resistance owing to easy penetration of water.

Developing a data-driven soft sensor to predict silicate impurity in iron ore flotation concentrate

Soft sensors are mathematical models that estimate the value of a process variable that is difficult or expensive to measure directly. They can be based on first principle models, data-based models, or a combination of both. These models are increasingly used in mineral processing to estimate and optimize important performance parameters such as mill load, mineral grades, and particle size. This study investigates the development of a data-driven soft sensor to predict the silicate content in iron ore reverse flotation concentrate, a crucial indicator of plant performance. The proposed soft sensor model employs a dataset obtained from Kaggle, which includes measurements of iron and silicate content in the feed to the plant, reagent dosages, weight and pH of pulp, as well as the amount of air and froth levels in the flotation units. To reduce the dimensionality of the dataset, Principal Component Analysis, an unsupervised machine learning method, was applied. The soft sensor model was developed using three machine learning algorithms, namely, Ridge Regression, Multi-Layer Perceptron, and Random Forest. The Random Forest model, created with non-reduced data, demonstrated superior performance, with an R-squared value of 96.5% and a mean absolute error of 0.089. The results suggest that the proposed soft sensor model can accurately predict the silicate content in the iron ore flotation concentrate using machine learning algorithms. Moreover, the study highlights the importance of selecting appropriate algorithms for soft sensor developments in mineral processing plants.

Environmental Controls of phytoplankton in the river dominated sub-tropical coastal ecosystem of Bangladesh

Sub-tropical coastal ecosystems are considered as the hotspot of species diversity. However, due to challenges regarding data collection, these regions are inherently data-limited and thus hindering informed species conservation strategies. Considering this, the present study aimed to assess the ecological characteristics of a river dominated sub-tropical coastal ecosystem of Bangladesh. More specifically, in this study we examined the spatial variability in environmental conditions and phytoplankton in the coastal ecosystems of Bangladesh. We also examined the causal relationship between environmental variables and phytoplankton species abundance. Data on environmental variables, including temperature, salinity, dissolved oxygen, turbidity, and macronutrients, was gathered in the north-east monsoon season between 2020 and 2022. We performed multivariate statistics to identify the variability in phytoplankton community dynamics. Results showed strong spatial variability in environmental conditions. Salinity, turbidity, nutrients concentrations and chlorophyll were found as the major drivers of this spatial heterogeneity. Central coast was characterized by low salinity, and high turbidity and silicate concentration while south-east coast was characterized by high salinity and low nutrient concentrations. In contrast, the south-west coast was characterized by high nitrate and phosphate, and moderate level of turbidity and salinity. Furthermore, our study identified 121 phytoplankton species. Maximum species diversity was observed in the south-west coast followed by central and south-east coast. Whereas 66 species occurred simultaneously in the three coastal zones, Coscinodiscus, Odontella and Nitzchia were the dominant phytoplankton genus in the central coastal zone. Skeletonema, Ditylum and Proboscia were found as dominant species in the south-east coastal zone. Coscinodiscus, Odontella, Nitzchia, Proboscia, Ditylum and Thalassionema were found as the key species in the south-west coastal zone. Seven explanatory variables (i.e. temperature, salinity, turbidity, silicate, nitrite, phosphate and zooplankton abundance) jointly explained about 44% to 73% variability in phytoplankton species abundance. We identified salinity and macronutrients as the major drivers of phytoplankton variability. This study is the first systematic report on phytoplankton community dynamics in-relation to environmental variables considering data from the entire coastal ecosystem of Bangladesh.

Pore Structure and Fractal Characteristics of Mixed Siliciclastic-Carbonate Rocks from the Yingxi Area, Southwest Qaidam Basin, China

Summary Evaluating reservoir properties at the pore scale is vital to better estimate hydrocarbon reserves and plan field development. The lacustrine mixed siliciclastic-carbonate deposits of the Upper Paleogene Xiaganchaigou Formation in the west Yingxiongling area form one of the most important hydrocarbon reservoirs in the southwestern Qaidam Basin (China). In this study, we analyzed well samples with X-ray diffraction (XRD), nuclear magnetic resonance (NMR), and mercury injection capillary pressure (MICP) data in integration with scanning electron microscopy (SEM) images to decipher the mineral composition and pore structure characteristics of the Xiaganchaigou Formation. We also calculate the fractal dimensions using MICP, NMR T2 spectrum, and SEM images based on fractal theory models. The results indicate that the mixed siliciclastic-carbonate samples of the upper section of the Xiaganchaigou Formation are mainly formed by dolomite and clay minerals with low siliceous and calcite content. Porosity is relatively low (2.01−9.83%) and positively correlated with dolomite content, thus indicating that the dolomite intercrystalline pores formed by infiltration and reflux dolomitization control the reservoir characteristics. The size of dolomite intercrystalline pores varies between several and hundreds of nanometers. The porosity has a poor correlation with permeability, which indicates that the pores are mostly primary, which lack the transformation of late dissolution. Three types of mixed siliciclastic-carbonate reservoirs are identified according to pore size distribution (<20 nm, 20−300 nm and multiple distribution), calculated using the NMR T2 spectrum. Fractal curves calculated by combining the MICP and NMR data are characterized by multisegments. The number of segments depends on the degree of heterogeneity of pore structure: two segment for high heterogeneity and three segment for low heterogeneity, also indicating a multifractal feature in mixed rock reservoirs. There is a negative correlation trend between porosity and fractal dimensions, and larger pores often have larger fractal dimensions. These results show that MICP-based fractal values are higher than those of NMR-based, which result from unconnected pores that the MICP is unable to reach. Fractal dimensions obtained from SEM have a small and narrow distribution range and are negatively correlated with the number of pores with smaller sizes. In essence, this study shows that the fractal dimension can be a concise index to evaluate the heterogeneity of lacustrine mixed siliciclastic-carbonate reservoirs, which can serve as an important reference for hydrocarbon development plans.

The surface structure of nanosilica produced from sodium silicate by the carbonation process

CO2 was used to prepare nanosilica particles through a carbonization reaction in a Na2SiO3 solution, aiming to convert CO2 into value-added products. The relationship between the specific structure of the as-prepared nanosilica and the sodium silicate concentration, reaction temperature, reaction time, and aging time was explored by TEM, BET, and XRD analysis. The growth process of nanosilica particles was relatively slow with the increase in the Na2SiO3 concentration, which resulted in the formation of large primary particles, reducing the specific surface area. The decreasing temperature reduced the polymerization of Si(OH)4 and SiOSi(OH)3, reducing the specific surface area. Meanwhile, the effects of reaction time and aging time on the surface structure of silica nanoparticles were studied. Different surface structure of nanosilica particles were synthesized by controlling the carbonization process conditions, which expand the application of nanosilica products. At present, the research on the carbonization preparation of nanosilica mainly focused on the carbonization process conditions and modification technology, but the research of control mechanism of nanosilica surface structure and properties was insufficient. This study focused on the relationship between surface structure evolution and properties, and provided a theoretical basis for the mechanism of the influence factors of preparation process on the structure evolution of prepared nanosilica. And the process reduced CO2 emission, which had important environmental protection value.

Determining drivers of phytoplankton carbon to chlorophyll ratio at Atlantic Basin scale

We demonstrate the ability of flow cytometry to determine species specific cellular carbon and chlorophyll content in vivo by using laboratory cultures of phytoplankton encompassing a wide range of cell sizes. When applied to the large Atlantic Meridional Transect flow cytometry dataset, we reveal patterns in the species-specific phytoplankton carbon (C), chlorophyll (Chl) and C:Chl ratio. For Prochlorococcus the range of C:Chl is between 2 – 604; for Synechococcus 0.5 – 558. Using a Random Forest machine learning approach, we show that predictability of phytoplankton C:Chl, dominated by the prevalence of Prochlorococcus, is largely driven by silicate and nitrite concentration in the Atlantic Ocean.

Plankton diversity and dynamics in the upper surface of the Indian sector of the Southern Ocean ecosystem and biogeochemical processes

In the Southern Ocean (SO) marine ecosystem, the interplay between CO2 sink and climate change is closely linked to the shifting plankton communities, leading to potentially wide-ranging biogeochemical effects. Within the Indian sector of the Southern Ocean (ISSO), the phytoplankton community was predominantly composed of Fragilariopsis spp., followed by Chaetoceros sp., while the zooplankton consisted mainly of Pleuromamma spp. and Oithona similis. Plankton diversity is collectively influenced by variables such as temperature, photosynthetically available radiation (PAR), and macronutrient availability. During the austral summer of 2019, significant latitudinal variations in phytoplankton were observed at major fronts in the region, including the Subtropical Front (STF), Sub Antarctic Front (SAF), Polar Front (PF), and South of Polar Front (SPF). At the STF, flagellates dominated (87%), while their presence decreased to 12% at the SPF, while diatoms progressively increased from the STF (<1%) to the SPF (87%) through the SAF and PF. Chlorophyll a (Chl-a) concentrations at the surface were highest in the PF (0.62 mg m−3), followed by the SPF (0.56 mg m−3), SAF (0.51 mg m−3), and STF (0.28 mg m−3). The integrated Chl-a values across the water column were higher at the SPF (21.49 mg m−2) than at the STF (14.73 mg m−2). The dominant diatom species at the surface along the fronts, except for STF, was Fragilariopsis spp. (∼5 × 105 Cells L−1), followed by Chaetoceros sp. (∼1 × 105 Cells L−1), and Coscinodiscus sp. (∼5 × 104 Cells L−1). Conversely, at the STF, the most abundant flagellate species were Gyrodinium spp. (∼2.4 × 104 Cells L−1), followed by Protoperidinium sp. (∼2 × 104 Cells L−1), and Amphidinium sp. (∼1 × 104 Cells L−1). Zooplankton biovolume in the upper 200 m ranged from 0.71 to 10 ml 100 m−3, with relatively higher biovolume and numerical abundance found in the SAF compared to the PF. The higher Chl-a concentration in the PF and lower zooplankton biovolume could have significant negative consequences for higher trophic levels. PAR showed higher values up to 40 m than observed depths along the fronts. Additionally, variations in salinity and temperature were recorded, with a significant decline in temperature from the STF to the SPF. Nitrate (NO3−), phosphate (PO43−), and silicate (SiO44−) concentrations were higher at the SPF than at lower latitudes. Overall, these findings indicate that the plankton community composition in the study region is influenced by a diverse set of governing variables over time, highlighting the significant implications for the regional biogeochemical cycle.

Response of Olive Seedlings (Olea europaea L.) Manzinilo Cultivar to Spraying with Potassium Silicate and Ascorbic Acid

This research was carried out in one of the private orchards in the district of Al-Musayyab / Babil during the season 2019-2020 with the aim of studying the effect of two factors, namely, spraying with three concentrations of potassium silicate (0,100,150 mg. L-1) and ascorbic acid with three concentrations of 0,100,200 mg. l-1), the experiment was designed as a factorial experiment according to the design of randomized complete blocks (RCBD) and with three replications, and the experimental unit included one seedling, so the number of experiment trees is 27 seedlings. The transactions were distributed randomly and using the SAS program to analyze the data. Spraying with potassium silicate and ascorbic acid at a concentration of 100 mg.l-1 each led to a significant increase in plant height, which amounted to 79.10 cm compared to the control treatment, which amounted to 47.00 cm, as well as its superiority in the number of branches, which reached 5 branches. seedlings -1 compared to the control treatment. Which amounted to 3.00 branch. seedlings-1, while the spraying treatment with potassium silicate and ascorbic at a concentration of 150 mg.l-1 each was superior in the characteristics of the number of total leaves. mg.l-1 and ascorbic at a concentration of 50 mg. l-1 in the characteristic of stem diameter, which amounted to 15 mm each, compared with the control treatment, which amounted to 10.24 mm, and the characteristic of leaf area, which amounted to 12.40 and 12.17 cm2 for each, respectively, while the comparison treatment for leaf area was 9.91 cm2.

Techniques of Arbuscular mycorrhiza as a Biofertilizer and an Anti-Transpiration for Promoting Plant Growth and Fruit Chemical Features of Pepper

The experiment was conducted in one of the fields in the Al-Azzawiya region - Al-Musayyib district 40 km north of the center of Babylon province, during the spring season 2022. The experiment included two factors, two types of mycorrhizae Glomus sp. and G. intraradices, and two concentrations of potassium silicate 3 ml.L−1 and 5 ml.L−1 in addition to control treatments to study their effect on the growth and chemical traits of the fruits. Sweet pepper plant California Wonder. The results showed that there were significant differences between the treatments of the two types of mycorrhiza. The addition of the imported mycorrhizal species G. intraradices significantly excelled on the local mycorrhiza Glomus sp in all studied growth traits. intraradices was distinguished by its significantly excelled in the type of structures causing colonization, the dendritic structure was 15.66 and the mycelium 1.18. As for the treatment of spraying with potassium silicate, it achieved spray treatment at a concentration of 5 ml. L−1 had a significantly excelled in most of the studied growth traits. As for the bi-interaction between G. intraradices and spraying at a concentration of 5 ml.L−1, it achieved the best results in study parameters. The experiment was carried out using a randomized complete block design, according to the split plot system, with a rate of three replications.

The Hydrological and Hydrochemical Structure of the Waters of the Bransfield Strait in January 2022

The work is devoted to the study of the abiotic characteristics in the waters of the Bransfield Strait in January 2022. The cross-section of January 2020 was repeated from the Antarctic Peninsula to the Southern Shetland Islands, as well as new data – 2 cross-sections in the eastern and western parts of the Strait. The scheme of currents in the Strait reflects modern knowledge, absolute values have been measured up to 50 cm/s in the northeast direction and up to 35 cm/s in the southwest. In the studied area, the modified waters of the Sea of Bellingshausen are clearly distinguished (warm and least salted, with reduced values of total alkalinity and all nutrients), the modified waters of the Wedell Sea (colder and salty, with reduced values of silicates and nitrates), as well as Circumpolar Deep Water in layer 200–450 m (warm and salty, with low values of dissolved oxygen and pH and an increased content of phosphates, silicates and nitrates). In the bottom waters of the Strait, there were no serious changes in the structure. The amplitude of the interannual variability of the abiotic characteristics of the waters of the Bransfield Strait is poorly expressed, nevertheless it can serve as a marker of climatic changes in the Southern Ocean.

Trace metal dissolution kinetics of East Asian size-fractionated aerosols in seawater: The effect of a model siderophore

Aerosol soluble metals are considered bioavailable to marine phytoplankton and may influence phytoplankton growth, their community structure, and material cycling in the ocean. The dissolution is controlled by the physical and chemical properties of aerosols and various atmospheric, physical, and biogeochemical processes before and after depositing in the surface water. Among these complicated processes, the interaction of aerosol metals with organic ligands in seawater is one of the major factors. In this study, we systematically investigated the dissolution kinetics of trace metals from fine (0.45–0.95 μm) and coarse (>7.2 μm) aerosols in seawater for 30 days under conditions with or without adding a model Fe organic ligand, siderophore desferrioxamine B (DFB). We found that most of the soluble metals in the fine aerosols were leached rapidly within the first hour. In terms of the coarse aerosols, with DFB addition, the fractional solubility of Fe increased substantially from 0.1 to 10%, and the solubilities of most other metals generally increased by about 2-fold within 30 days. Without DFB addition, we found that most soluble metals were still gradually released over time in coarse aerosols, except particle-reactive metals, Fe and Pb. We further observed strong linear correlations between dissolved metals (Al, Fe, Mn, Co, Ni, and Zn) and silicate concentrations for DFB addition with coarse aerosols, with metal to silicate ratios comparable to those of typical aluminosilicates. Quantitatively, the aluminosilicate-associated dissolved metals accounted for >85% of total dissolved Fe, Al, and Co, and 40–60% for total dissolved Mn and Ni with the addition of DFB for 30 days. By comparing dissolved metal to Al ratios with lithogenic ratios, the metals leached in the first hour for both coarse and fine aerosols originated from anthropogenic sources, and lithogenic aerosols gradually became the dominant soluble metal source for coarse aerosols after 1 h, extending to 720 h. The findings of this study exhibit the importance of the time-dependent interaction of lithogenic aerosols with organic ligands in seawater. The residence time of aerosol particles and the concentrations of available organic ligands in the euphotic zone are key factors affecting aerosol dissolved metal availability to marine phytoplankton in the surface ocean.