Water pH Research Articles

Patterns of carbonate chemistry in mangroves of the Northern Persian Gulf

The mangroves located in the Northern Persian Gulf are reeling from anthropogenic pressures including from intense industrial activities (Pars Special Economic Energy Zone-PSEEZ). Given the unique geographical location of these mangroves, understanding the initial basis of seawater carbonate chemistry is key to link with global patterns of coastal ocean carbonate dynamics. In this study, water samples were collected from pre-designated stations representing the mangrove forest and nearshore water namely Nayband, Mel-e-Gonzeh and Bardestan of the Persian Gulf in September of 2016. Based on extensive carbonate chemistry measurements, the results show that the pCO2 at the Nayband site (13217.9±5841.5 µatm) was significantly higher than the other two sites (Mel-e-Gonzeh: 416.4±49.3 µatm and Bardestan: 294.3±95.0 µatm) while pH (6.92±0.18) was significantly lower than the two other sites (Mel-e-Gonzeh: 8.18±0.02, Bardestan: 8.26±0.04). The observed increase of pCO2 and decrease of surface water pH at the Nayband site compared to other two sites may have due to the emission of CO2 originating from oil and gas refining facilities located PSEEZ. Moreover, surface water in Nayband was undersaturated with respect to aragonite (Ωarg<1) and supersaturated (Ωarg>1) in case of the Mel-e-Gonzeh and Bardestan sites. This study although preliminary provides much-needed baseline information to address issues of changing carbonate chemistry and can help towards understanding the basis of coastal ocean acidification.

Analysis of Pile Foundation for Hospital Buildings

Pile foundations are widely employed to provide support for bridges and various structures, ensuring the safe transfer of structural loads to the ground while preventing excessive settlement or lateral movement. They excel in transferring structural loads from weaker or compressible soil layers to the stronger, more stable soils and rocks beneath. Pile foundations constitute an integral component of a structure.  In this research work the foundation of the hospital (G+6) was design by the pile foundation. We have used M25 grade of concrete for the preparation of design mix. The characteristic strength and load bearing of soil was tested by Plate load test and other materials tested by slump cone test , aggregate Impact Value test cement compressive strength test (cement fineness test construction water PH value . The expected result of SBC is 20000kg approximate.  Project reports typically encompass introductions and problem definitions, along with literature reviews pertinent to the project. They detail the study area's location and the project site, as well as providing concise information about the equipment utilized on- site.  Additionally, it covers crucial tasks such as centerline marking, boring, reinforcement placement, concrete pouring, excavation, and chipping of pile caps.

Shifts in Microbial Community Structure and Co-occurrence Network along a Wide Soil Salinity Gradient.

The response of microbiomes to salinity has been clarified in different geographic scales or ecosystems. However, how soil microbial community structure and interaction respond to salinity across wide salinity range and climatic region is still unclearly resolved. To address this issue, we examined the microbial community's composition in saline soils from two climatic regions (coastal wetland and arid desert). Our research confirms that soil salinity had a negative effect on soil nutrient content. Salinity decreased the relative abundance of bacteria, but increased archaea abundance, leading to the shifts from bacteria dominant community to archaea dominant community. Low-water medium-salinity soil (LWMS) had the most complex archaeal community network, whereas for bacteria, the most complex bacterial community network was observed in low-water high-salinity soils (LWHS). Key microbial taxa differed in three salinity gradients. Salinity, soil water content, pH, total nitrogen (TN), and soil organic carbon (SOC) were the main driving factors for the composition of archaeal and bacterial community. Salinity directly affected archaeal community, but indirectly influenced bacteria community through SOC; pH affected archaeal community indirectly through TN, but directly affected bacterial community. Our study suggests that soil salinity dramatically influences diversity, composition, and interactions within the microbial community.

Optimizing fertilizer usage for source reduction of salt and fluoride ion runoff discharge from a soda saline-alkali paddy field

Planting rice is a beneficial strategy for improving soda saline-alkali soil, but it comes with the challenge of increased runoff discharge of salt and fluoride (F−) ions. The use of different nitrogen (N) fertilizers can impact this ion discharge, yet the specific characteristics of ion runoff under different N-fertilizer applications remain unclear. A field experiment was conducted in this study, applying five commonly used N-fertilizer types to monitor the ion runoff throughout an entire rice growing season. Salt ions and F− runoff discharge was significantly affected by N-fertilizer type, runoff event, and their interaction (p < 0.001). Regardless of N-fertilizer types, sodium (Na+) and bicarbonate (HCO3−) ions were consistently discharged from runoff in soda saline-alkali fields, constituting 20.55–25.06 % and 47.57–50.49 % of total ion discharges, respectively. Compared to no N-fertilizer (CK) and other N-fertilizer treatments, the organic-inorganic compound fertilizer (OCF) application significantly reduced Na+ and HCO3− runoff discharge, causing a decrease in the competitive adsorption capacity between HCO3− and F− (p < 0.05). The use of OCF and inorganic compound fertilizer (ICF) lowered pH in runoff water, resulting in reduced dissolution capacity of calcium fluoride in the soil and thereby decreasing total F− runoff discharge. In conclusion, OCF proves to be an effective N-fertilizer in mitigating salt ions and F− runoff discharge in soda saline-alkali paddy fields. Additionally, ICF demonstrates the ability to control F− runoff discharge.

Effect of Salt Concentration and Fermentation Time In The Development of Anchovy (Stolephorus Sp) Bekasam as Tempura Raw Material

Purpose: This study aimed to analyze the effect of salt concentration and fermentation time on the chemical characteristics and lactic acid bacteria of anchovy bekasam, and the sensory evaluation of anchovy bekasam as a raw material for tempura. Methodology: The tests conducted included water content (thermogravimetry), pH (pH meter), fat content (soxhlet), bacterial count (TPC), and sensory evaluation (hedonic). The study used a Randomized Complete Block Design (RCBD) with two factors: salt concentration (15% and 20%) and fermentation time (4 days and 7 days).Results: The results indicated that both salt concentration and fermentation time significantly affected the water content, pH, and total lactic acid bacteria. The fat content was not significantly affected by the two factors but showed a decrease. Findings: Variations in salt concentration and fermentation time influenced the panelists' sensory preferences for color, aroma, taste, texture, and overall acceptability. The highest overall liking score was achieved by the sample with 15% salt concentration and 7 days of fermentation (K1L2). Novelty: This research provides insight into the optimal conditions for producing anchovy bekasam with desirable chemical and sensory properties, specifically for its use as a raw material for tempura. Originality: The study highlights the impact of different salt concentrations and fermentation times on both the chemical and sensory characteristics of bekasam, offering new information on improving its production process. Conclusions: The sample with 15% salt concentration and 7 days fermentation time yielded the most favorable results in terms of both chemical characteristics and sensory evaluation. Paper Type: Experimental Research Article Keywords: Bekasam; fish; fermentation; salt; tempura

Fluoride concentration and pH in bottled waters commercialized in Chile: Implications for oral health

An increased consumption of bottled water is overshadowing the traditional intake of tap water. Community water fluoridation is described an effective public measure for delivering fluoride (F) for dental caries prevention. Although community water fluoridation implementation varies regionally, it is desirable that our daily water contains optimal fluoride levels and a safe pH for dental health protection. Here, we determined F concentration and pH of commercially available bottled waters in Chile. Varieties (mineral, purified, and flavored) were obtained in duplicate from different batches. F and pH were measured using a calibrated F-specific ion electrode and pH meter, respectively. From 76 different brands, 100 % have F concentrations below the recommended range (0.6–1.0 ppm F), mineral water showing significantly higher levels (0.15±0.009; p<0.05) than purified (0.09±0.080), and flavored (0.07±0.063). Most brands exhibited levels below the critical pH for both enamel (71.05 %, n=54) and dentine (80.26 %, n=61). A 46.1 % (n=35) had values below pH 4. Flavored waters had significantly lower pH (3.19±0.12; p<0.05), than purified (6.16±2.81) and mineral (pH 6.21±2.59). The analyzed bottled water, regardless of type, lack sufficient F for caries prevention. Their low pH, particularly in flavored options, might be related to an increased risk of erosive tooth wear. Implementing fluoride and pH labeling is desirable to empower consumers to make informed decisions.

Characterization of medium and small-scale gold processing operations, wastewaters, and tailings in the Arequipa region of Peru

Gold cyanidation facilities in the Arequipa Region of Peru are challenged by the availability and quality of water for processing in an arid environment. The facilities reuse decant water which recycles residual cyanide but also undesirable constituents. To understand the impact of intensive water recycling on cyanide and metals concentrations, we collected barren water, decant water, and tailings samples from six gold cyanidation facilities with ore capacities of 10–430 tons per day. Processing facilities in Arequipa recycle all effluents, with decant waters making up 58 ± 11 % of process waters. Decant water contained non-target metals: copper (394 ± 161 mg/L), iron (59 ± 34 mg/L), and zinc (74 ± 42 mg/L). In addition, decant water mean free and complexed cyanide concentrations were 534 ± 129 mg/L and 805 ± 297 mg/L, respectively. Complexed cyanide concentrations remained more constant than free cyanide concentrations with 786 ± 299 mg/L for barren water and 805 ± 297 mg/L for decant water. Cyanide mass balances showed between 21 % and 42 % of unaccounted free cyanide from the start of gold cyanidation and discharge to the tailings storage facility (TSF). Free cyanide estimated losses due to volatilization were 0.8 kg and 2.5 kg of hydrogen cyanide per ton of ore processed at barren water pH of 10.1 and 9.7. Together these results indicate two acute hazards: 1) volatilization of free cyanide during processing and 2) loading and retention of cyanides and metals into TSFs. This study elucidates the extent of uncontrolled vapor phase cyanide release during gold processing operation and contaminant concentrations in the tailings storage facilities. The data highlights the need for improvement oversight, accountability, and regulation of gold processing facilities practicing intensive recycling and zero discharge.

Estimación de analitos del suelo en la altillanura, con teledetección sentinel-2 y modelos de regresión

Contextualization: Incorporation of new techniques and technologies to know the characteristics and composition of soils used in agricultural production is booming. The free license products such as Sentinel-2 satellite images, allow correlating the edaphic properties with spectral indices. Knowledge gap: In the agricultural sector, the indices calculated from satellite images have been centered on characterization of vegetation. To a lesser proportion, studies have been carried out with indexes used in mineral prospecting to correlate with the chemical characteristics of the soil. Purpose: This study was developed to evaluate the correlation of ferric oxide, ferrous silicate, ferrous iron, and alteration indices with the content of chemical elements of importance in crop production. Methodology: A crop field of 282 hectares in the municipality of Puerto López in the department of Meta was selected. The evaluated indices from a set of Sentinel-2 imagery were calculated. After indices obtention, 40 sites were selected to do a soil composite sampling and determine the following characteristics: pH in water (1:1 potentiometric), Organic Matter (Walkey and Black), P (Bray II), Al (KCl 1N), Ca, Mg, K y Na (Ammonium acetate), Fe (DTPA). With the obtained information, a multiple regression analysis using the stepwise method was performed; as independent variables, the raster layers of the indexes calculated were used, and the variable to predict were the properties determined in the laboratory. Results and conclusions: The evaluated indices showed a higher correlation to 0.60 with Ca and Mg content. A correlation between 0.40 and 0.60 was found between the indices and organic carbon y Fe. The regression models calculated give adjustments of 0.54, 0.47, and 0.33 for Mg, Ca, and Fe, respectively. The findings of this research allow us to understand from Sentinel-2 images that it is possible to obtain relevant indexes for agricultural production in conditions of the Colombian Plateau.

Nonthermal plasma processing catalyzed by CuFe2O4 for organic pollutants remediation and bacterial inactivation with density functional theory

The suggested nonthermal plasma has been employed for organic pollutants remediation and bacterial inactivation with catalyst (CuFe2O4) via reactive oxygen and nitrogen species, along with catalytic density functional theory processing. The plasma generated species O2− (g.), OH• (g.), H2O2 (aq.), and NOx (aq.) are used for the remediation of organic pollutants, such as reactive black5 and bromocresol green with catalytic oxidative and reductive transformation, like as from Fe2+ (aq.) to Fe3+ (aq.) and from Cu2+ (aq.) to Cu1+ (aq.), respectively. In the presence of plasma with CuFe2O4, the pollutants remediation enhanced more, which is 95 ± 0.78%, rather than only plasma. After removal of pollutants, the plasma processing catalyzed by CuFe2O4 was highly inactivated the E. coli. bacterial growth, which inhibition rate is 100 ± 0.87% and 100 ± 0.69% for reactive black5 and bromocresol green, rather than only plasma, such as 86.41 ± 0.91% and 73.91 ± 0.56%, respectively. The CuFe2O4 generated super oxides (O2− (aq.)) and hydroxides (H+(aq.), OH⦁(aq.), and OOH⦁(aq.)) are rapidly react with bacteria to damage the bacterial cell membrane via catalytic redox process. However, the plasma generated species were react with catalyst to produce the e− charge densities under the redox transformation of spin orientation (±) 0.58 e−, which is 0.007, 0.009, and 0.005 electrons per cubic Angstrom, for CuFe2O4, H2O2(aq.), and NOx(aq.). The plasma generated species concentrations were quantified in the deionized water, which are H2O2(aq.) (145 ± 0.91 μM) and NOx(aq.) (112 ± 0.56 μM), respectively. After eradication of pollutants, the water pH was observed, which is near to the neutral at 6.57 ± 0.27 under the catalytic binary redox process. Moreover, the catalytic stability examined via reusability test, which were four cycles for reactive black5 and three cycles for bromocresol green. Furthermore, the CuFe2O4 nanoparticles conducted several characterizations to analyze the various properties, such as crystal, surface, functional, and elemental.

Dynamics of Phytoplankton Communities and Environmental Drivers in Chinese Mitten Crab Aquaculture Ponds: Highlighting the Need for Cyanobacteria Control

Pond culture is the primary method for cultivating Chinese mitten crab (Eriocheir sinensis), with phytoplankton significantly influencing their growth. Green algae benefit crab growth by serving as supplementary food, while cyanobacteria, particularly during blooms, hinder it and pose health risks. Environmental changes in nutrient levels, temperature, and light significantly affect phytoplankton communities in ponds, impacting both ecosystem stability and crab growth. However, there is a limited understanding regarding the patterns of phytoplankton changes within adult Chinese mitten crab culture ponds. This study conducted monthly collection and analysis of phytoplankton throughout the culture cycle in typical adult Chinese mitten crab culture ponds, concurrently measuring physical and chemical water parameters to explore the correlation between phytoplankton changes and environmental factors. The results revealed distinct seasonal variations in phytoplankton composition. Chlorophyta and Bacillariophyta, such as Chlorella, Pediastrum, and Cocconeis, predominated in spring, while Chlorophyta and cyanobacteria, such as Volvox, Anabaena, and Microcystis, dominated in summer, and cyanobacteria and Bacillariophyta, such as Microcystis, Dolichospermum, and Cocconeis, prevailed in autumn. Total phytoplankton density consistently increased throughout the culture period. Microcystis constituted the majority of cyanobacteria biomass throughout most months. Although the total phytoplankton biomass fluctuated, cyanobacteria biomass consistently rose each month, reaching a peak of 61.7 mg/L in October. Water temperature and pH emerged as the primary environmental drivers influencing changes in phytoplankton community structure. Cyanobacteria density reached its peak between 18 and 26 °C and at a pH range of 7.5–8.5. These findings highlight the need for environmental regulation and cyanobacteria control in Chinese mitten crab culture ponds, thus promoting the health and sustainability of the Chinese mitten crab culture.

Modelling anisotropic surface charge of kaolinite particles depending on pore water pH

This paper proposes a new, computationally efficient, approach to modelling the anisotropy of surface charge on kaolinite particles in particle-scale simulations. We represent each kaolinite particle as a flat ellipsoid and calculate the total interaction energy/force between two ellipsoids as a weighted sum of face-to-face, edge-to-edge, face-to-edge, and edge-to-face interactions. The weightings of these interactions are smooth functions of the relative orientations of the particles. This model was employed in coarse-grained molecular dynamics simulations of virtual samples under isotropic compression to investigate the influence of the pore water pH on microfabric formation and the mechanical behaviour of kaolinite. The simulations effectively captured the influence of pore water pH on microfabric formation and compressive behaviour, as previously reported in experimental research. The virtual sample with a pore water pH of 4 (acidic pore water) formed an aggregated and flocculated microfabric and exhibited higher compressibility during isotropic compression. In contrast, the virtual sample with a pore water pH of 8 (alkaline pore water) formed a dispersed and deflocculated microfabric and showed lower compressibility. The efficacy of the model is demonstrated here through coarse-grained molecular dynamics simulations, but it could also be implemented in a discrete element method code.

Isotherm, Kinetics, and Adsorption Mechanism Studies of Coal Gasification Coarse Slag as Highly Efficient Phosphate Adsorbents

This study investigates the efficacy of a novel low-cost phosphate adsorbent, denoted as SH-CGCS, derived from coal gasification coarse slag (CGCS) via an alkali activation method. SH-CGCS is a mesoporous material with a specific surface area (64 m2/g) approximately six times larger than CGCS (11 m2/g), which enhances its adsorption capacity compared with CGCS. Furthermore, SH-CGCS achieves a phosphate adsorption capacity of 38.5 mg/g in strongly acidic water (pH 3) and demonstrates robust acid resistance, which makes it particularly effective for phosphate removal from acidic wastewater. Results from coexisting anion experiments affirm the good adsorption selectivity of SH-CGCS for phosphate. Moreover, SH-CGCS exhibits proficiency in treating water containing low phosphate concentrations under flowing conditions. The maximum phosphate adsorption capacity of SH-CGCS calculated using the Langmuir model is 23.92 mg/g, surpassing that of other reported adsorbents. Importantly, saturated SH-CGCS can be regenerated and reused, which contributes to its practical applicability. The adsorption mechanisms of SH-CGCS for phosphate involve ligand exchange, inner-sphere complexation, surface precipitation, and electrostatic adsorption. Thus, this study not only enhances the overall utility of CGCS but also presents a simple and efficient method for removing phosphate. Our findings indicate that SH-CGCS holds considerable potential as a phosphate adsorbent, offering a promising solution for wastewater treatment.

The influence and mechanism exploration of hydration environment on the stability of natural clay crude oil emulsion

The study investigated the effects and mechanisms of clay content, emulsion water content, pH, and metal cations on clay-crude oil emulsions. The results indicate the following: 1) At a water content of 50 V/V%, montmorillonite can form emulsions with crude oil at different concentrations, with the highest stability observed at 5 wt% content. In contrast, chlorite, illite, and kaolinite cannot form emulsions at low concentrations. 2) Under acidic conditions, montmorillonite, illite, and chlorite cannot form emulsions with crude oil, or the emulsions are highly unstable. However, kaolinite forms more stable emulsions under acidic conditions. In alkaline environments, emulsions formed by all clay minerals exhibit increased stability. 3) The order of the effectiveness of different metal cations in reducing the stability of montmorillonite-crude oil emulsions is K+ &amp;gt; Na+ &amp;gt; Mg2+ &amp;gt; Ca2+, while for chlorite, illite, and kaolinite, it is Mg2+ &amp;gt; Ca2+ &amp;gt; K+ &amp;gt; Na+. 4) The factors that influence the stability of clay-crude oil emulsions are the arrangement of clay particles in water and the dispersion capability of clay particles in water. The most significant influencing factor is the arrangement of clay particles in water.

Impact of pH and High-Pressure Pasteurization on the Germination and Development of Clostridium perfringens Spores under Hyperbaric Storage versus Refrigeration.

This study aimed to evaluate hyperbaric storage at room temperature (75-200 MPa, 30 days, 18-23 °C, HS/RT) on Clostridium perfringens spores in brain-heart infusion broth (BHI-broth) at pH 4.50, 6.00, and 7.50 and coconut water (pH 5.40). Both matrices were also pasteurized by high pressure processing (600 MPa, 3 min, 17 °C, HPP) to simulate commercial pasteurization followed by HS, in comparison with refrigeration (5 °C, RF). The results showed that, at AP/RT, spores' development occurred, except at pH 4.50 in BHI-broth, while for RF, no changes occurred along storage. Under HS, at pH 4.50, neither spore development nor inactivation occurred, while at pH 6.00/7.50, inactivation occurred (≈2.0 and 1.0 logs at 200 MPa, respectively). Coconut water at AP/RT faced an increase of 1.6 logs of C. perfringens spores after 15 days, while for RF, no spore development occurred, while the inactivation of spores under HS happened (≈3 logs at 200 MPa). HPP prior to HS seems to promote a subsequent inactivation of C. perfringens spores in BHI-broth at pH 4.50, which is less evident for other pHs. For HPP coconut water, the inactivation levels under HS were lower (≈2.0 logs at 200 MPa). The Weibull model well described the inactivation pattern observed. These results suggest that HS/RT can be simultaneously used as a tool to avoid C. perfringens spores' development, as well as for its inactivation, without the application of high temperatures that are required to inactivate these spores.

Bio-regeneration for Sodium Silicate Used Sands and its Unattended Monitoring System

Sodium silicate, known for its low cost and non-toxicity, has been considered as a promising option for green foundry in terms of mould sands. However, the utilization of used sodium silicate sands has posed significant challenges. To address the issues of high energy consumption and secondary pollution associated with wet and dry regeneration of sodium silicate used sands, this paper proposes a novel unattended biological regeneration system. The system involves culturing diatoms in an incubator with a solution of sodium silicate used sands. The incubator is equipped with built-in sensors that continuously monitor temperature, illuminance, pH, and water level. The monitoring data is transmitted in real-time to the Yeelink Internet of Things platform via the controller using the TCP/IP protocol. By logging onto the corresponding web page, the experimenter can remotely observe the monitoring data. The results of the experiment indicate that diatoms bloomed five times, and the water pH decreased from 10.2 to 8.2 after 40 days of cultivation. Additionally, the film removal rate of the used sands reached 90.26%.

The use of CO2 for the treatment of alkaline tunnel construction wastewater: Efficiency and influencing factors

Alkaline wastewater from tunnel construction can cause environmental problems when draining into water streams like rivers and lakes. Research interest in the neutralization of alkaline wastewater using CO2 based on the carbon utilization concept has been increasing. In this study, the effects of key parameters such as the flow rate (FR) of CO2, initial water temperature (T), pH, and turbidity (TURB) on CO2 neutralization of alkaline wastewater were investigated through laboratory experiments and field tests using alkaline wastewater collected from the Yunnan Dianzhong Water Diversion Engineering, China. Results revealed that 1.5 L min−1 was the optimal flow rate for CO2 gas. The water pH (p < 0.001) and TURB (p < 0.001) significantly affected the neutralization performance of CO2. The pH, TURB, electrical conductivity and total dissolved solids of alkaline wastewater can be effectively reduced by CO2. The least time required for the treatment was noted at a T, pH, and TURB of 20 °C, 10.5, and 80 NTU, respectively. Laboratory and field stability experiments have shown CO2 to be effective in reducing the pH of alkaline wastewater and consistently maintaining its pH within the discharge standard compliance range (6–9). A cost saving of $0.26 per 1 m3 of water was achieved comparing with neutralization of alkaline wastewater using citric acid. In summary, this study for the first time explored the efficiency and potential influencing factors for the treatment of alkaline tunnel construction wastewater using CO2. It proves the effectiveness and economic benefits of the proposed technology.

Aggregation-induced emission active multianalyte sensor: Detection of pH, carbonate, bi-carbonate and nitroaromatics in water

An aggregation-induced emission (AIE) based multi-tasking probe DAAQ (5-(dimethylamino)-N-(9,10-dioxo-9,10-dihydroanthracen-2-yl)naphthalene-1-sulfonamide) has been reported for detecting multiple analytes such as anions (carbonate and bicarbonate ions) and nitroaromatic compounds (2,4-DNP and TNP). Probe DAAQ displayed the photophysical properties of aggregation-induced emission (AIE) in DMSO-water mixture, acidochromism and detected various analytes, making DAAQ a multi-tasking probe. DAAQ respond to carbonate and bicarbonate (CO32− and HCO3−) with a colour change from pale yellow to dark orange. The limit of detections (LOD) was estimated as 0.486 mg/L and 41.35 mg/L for CO32− and HCO3−, respectively. The applications of DAAQ were also explored to detect CO32− ions in water samples collected from various sources and soft drinks. Further, the probe also explored detecting neural aromatic compounds such as 2,4-DNP and TNP by a naked eye colour change and the LODs were calculated as 12.6 µM and 8.19 µM, respectively. DFT calculations were applied for the confirmation binding studies of DAAQ with multiple analytes. The sensing of 2,4-DNP and TNP were achieved through PET with a Turn-Off response. The sensing mechanisms were confirmed with 1H NMR experiments.

Sulphate reduction and carbonate precipitation in a high-energy algal rim framework

Algal ridges are protective features for coral reefs that form through the accretion and encrustation of reef rubble and debris by crustose coralline algae (CCA) and processes of diagenetic cementation. Carbonate precipitation and dissolution dynamics on and within algal ridge frameworks are poorly understood. We studied the surface and subsurface geochemistry of the algal ridge framework at One Tree Island, Australia. Measurable quantities of hydrogen sulphide were detected in most porewater samples collected from bores, indicating a largely anoxic ridge framework. Total alkalinity (TA) and pH measurements indicate that the precipitation of carbonate minerals within the interior of the ridge framework occurs under largely anoxic conditions and is likely to be driven by TA changes associated with sulphate-reducing bacteria. Modelling of porewater hydrogen sulphide concentrations in combination with TA and dissolved inorganic carbon (DIC) indicates anoxic respiration processes produce alkalinity within the algal ridge framework. However, significantly more TA is removed via the precipitation of mineral carbonate, resulting in porewater TA concentrations falling below the open seawater values. The precipitation of mineral carbonate also lowers interstitial water pH, such that pH changes are not solely from organic carbon diagenesis. The simultaneous precipitation and dissolution of carbonate minerals within the algal ridge framework are key to forming and cementing algal ridges, which are important physical protective features for coral reefs.

Altitude Distribution Characteristics of Farmland Soil Bacteria in Loess Hilly Region of Ningxia

It is of great significance for the conservation of biodiversity in farmland ecosystems to study the diversity, structure, functions, and biogeographical distribution of soil microbes in farmland and their influencing factors. High-throughput sequencing technology was used to analyze the distribution characteristics of soil bacterial diversity, community structure, and metabolic function along elevation and their responses to soil physicochemical properties in farmland in the loess hilly areas of Ningxia. The results showed that:① The Alpha diversity index of soil bacterial was significantly negatively correlated with elevation (P &lt; 0.05) and showed a trend of decreasing and then slightly increasing along the elevation. ② Seven phyla, including Proteobacteria, Actinobacteria, and Acidobacteria, were the dominant groups, and five of them showed highly significant differences between altitudes (P &lt; 0.01). ③ At the secondary classification level, there were 36 metabolic functions of bacteria, including membrane transport, carbohydrate metabolism, and amino acid metabolism, of which 22 showed significant differences, and 12 showed extremely significant differences among different altitudes. ④ Pearson correlation analysis showed that soil water content, bulk density, pH, and carbon-nitrogen ratio had the most significant effects on bacterial Alpha diversity, whereas soil nutrients such as total organic carbon, total nitrogen, and total phosphorus had significant effects on bacterial Beta diversity. ⑤ Mantel test analysis showed that the soil water content, total organic carbon, and carbon-nitrogen ratio affected bacterial community structure at the phylum level, and soil pH, total organic carbon, total nitrogen, total phosphorus, and carbon-nitrogen ratio were significantly correlated with bacterial metabolic function. Variance partitioning analysis showed that soil water content had the highest explanation for the community structure of soil bacteria, whereas soil pH had the highest explanation for metabolic function. In conclusion, soil water content and pH were the main factors affecting the diversity, community composition, and metabolic function of soil bacteria in farmland in the loess hilly region of Ningxia.

Water Quality Monitoring System Based on the Internet of Things (IoT) for Vannamei Shrimp Farming

As Internet of Things (IoT) technology develops, water quality monitoring systems for Vannamei shrimp farms have become more inventive and straightforward. The prototype IoT system monitors and controls the pool using sensors that can measure water quality parameters, such as temperature, pH, and salinity. The research aimed to design an automated water quality monitoring system for Vannamei shrimp aquaculture. The research used the E-4052C sensor, DS18B20 sensor, and DFRobot V1.0 sensor as data transmitting hardware (transmitter) and the receiving hardware microcontroller NodeMCU ESP32 as data processing, management, and control system tools. Then, the system used a Wi-Fi network to transfer data from the microcontroller to the Message Queue Telemetry Transport (MQTT) server as a data cloud. Several software programs, including Telegram, Node-Red, and ThingSpeak, help Android devices display real-time data. Test results for the accuracy of the sensor’s reading on water pH are 99.71, with an error rate of 0.29%. Meanwhile, the accuracy of the temperature sensor is 98.03 with an error rate of 1.7%. On the other hand, the accuracy of the salinity sensor is 99.49, with an error rate of 0.41%. The results indicate that all sensors have excellent performance. The real-time monitoring display and Android Telegram notification functions are good, and the automatic water quality monitoring tool is successfully operating in the Vannamei shrimp pool in Pamandati, South Konawe District, Southeast Sulawesi ssProvince, Indonesia.