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Methanotrophs are important microbial communities in coastal ecosystems. They reduce CH4 emission in situ, which is influenced by soil conditions. This study aimed to understand the differences in active aerobic methanotrophic communities in mangrove forest soils experiencing different inundation frequency, i.e., in soils from tidal mangroves, distributed at lower elevations, and from dwarf mangroves, distributed at higher elevations. Labeling of pmoA gene of active methanotrophs using DNA-based stable isotope probing (DNA-SIP) revealed that methanotrophic activity was higher in the dwarf mangrove soils than in the tidal mangrove soils, possibly because of the more aerobic soil conditions. Methanotrophs affiliated with the cluster deep-sea-5 belonging to type Ib methanotrophs were the most dominant methanotrophs in the fresh mangrove soils, whereas type II methanotrophs also appeared in the fresh dwarf mangrove soils. Furthermore, Methylobacter and Methylosarcina were the most important active methanotrophs in the dwarf mangrove soils, whereas Methylomonas and Methylosarcina were more active in the tidal mangrove soils. High-throughput sequencing of the 16S ribosomal RNA (rRNA) gene also confirmed similar differences in methanotrophic communities at the different locations. However, several unclassified methanotrophic bacteria were found by 16S rRNA MiSeq sequencing in both fresh and incubated mangrove soils, implying that methanotrophic communities in mangrove forests may significantly differ from the methanotrophic communities documented in previous studies. Overall, this study showed the feasibility of 13CH4 DNA-SIP to study the active methanotrophic communities in mangrove forest soils and revealed differences in the methanotrophic community structure between coastal mangrove forests experiencing different tide frequencies. [ABSTRACT FROM AUTHOR]

Investigation of the weathering of silicate minerals is helpful to understand the process of soil development, cycling of nutrient elements, and potential applications in fixation of carbon dioxide from the atmosphere through carbonate precipitation. In this study, weathering experiments of calcium-montmorillonite were conducted using Paenibacillus sp. strain SB-6 for 70 days. The results indicated that the Si4+, Al3+, Ca2+ and Na+ concentrations in the medium of the biotic experiments were evidently higher than those of the abiotic experiments, and that Paenibacillus sp. could help the transformation of partial montmorillonite into an illite–montmorillonite mixed-layer. In the process of illitization, K+ went into the interlayer of montmorillonite and hydrated Ca2+ and Na+ released from it. In the late stage of the experiments, the Ca2+ released from montmorillonite combined with carbonate ions generated by the bacterial metabolism, forming calcite. [ABSTRACT FROM AUTHOR]

Understanding the influence of complex interactions among hydrological factors, soil characteristics and biogeochemical functions on nutrient dynamics in overland flow is important for efficiently managing agricultural nonpoint pollution. Experiments were conducted to assess nutrient export from Ultisol soils in the Sunjia catchment, Jiangxi province, southern China, between 2003 and 2005. Four plots were divided into two groups: two peanut plots and two agroforestry (peanut intercropped with citrus) plots. During the study period, we collected water samples for chemical analyses after each rainfall event that generated overland flow to assess nutrient export dynamics. The concentrations of potassium (K) and nitrate-N (NO3--N) in overland flow were higher during the wetting season (winter and early spring). This reflects the solubility of K and NO3--N, the accumulation of NO3--N during the dry season and an increase in desorption processes and mixing with pre-event water caused by prolonged contact with soil in areas with long-duration, low-intensity rainfall. In contrast, concentrations of total nitrogen (TN) and total phosphorus (TP) were higher during the wet season (late March to early July) and during the dry season (mid-July to the end of September or early October). This was due to the interaction between specific hydrological regimes, the properties of the Ultisol and particulate transport processes. Variations in nutrient concentrations during storm events further identified that event water was the dominant source of total nitrogen and total phosphorus, and pre-event water was the dominant source of NO3--N. In addition, the results obtained for the different land uses suggest that agroforestry practices reduce nutrient loss via overland flow. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Purpose – The purpose of this paper is to identify underlying personal values that determine the mall shopping behaviour of Chinese consumers and to propose shopping intention as an additional mediator that enhances the value-behaviour link. Design/methodology/approach – A self-administered web-based survey with convenience sampling was used to collect the data. A structural equation modeling technique was used to test the proposed model. Findings – Chinese mall shoppers' behaviours were found to be explained by value orientations which were both similar and different from their counterparts in the West. While Western mall shoppers are more likely to be directed by social affiliation and self-actualising values in previous studies, Chinese mall shoppers are more likely to be influenced by self-transcendence and self-enhancement (similar to self-actualising) values in the present study. Additionally, shopping intention was found to improve the predictive power of consumers' attitude toward mall attributes in terms of shopping frequency and money spent in the mall. Research limitations/implications – The main limitation of this study is related to measurement error, derived from using simplified instruments to measure personal values. In addition, both personal values and attitudes are abstract constructs, which are difficult to measure; therefore this may also contribute to a larger error variance. Practical implications – The results of this study are especially beneficial for mall developers and retailers for crafting effective positioning strategies and guiding their communication strategies in the China market. Originality/value – The proposed model makes a theoretical contribution by testing a Western theory in a non-Western context. In addition, the proposed model helps researchers better understand the value-behaviour relationship in a more comprehensive framework. [ABSTRACT FROM AUTHOR]

The structure and composition of the bacterial community associated with buoyant Microcystis colonies were monitored during the decline of a cyanobacterial bloom (from October 13, 2009 to January 27, 2010). When temperature decreased, the ratio between the colony-associated bacteria and the Microcystis gradually decreased as estimated by a quantitative real-time polymerase chain reaction (qRT-PCR)-based approach. Diversity of bacterial communities was determined through denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene fragments. Cluster analysis of the DGGE profiles showed that most of the bacterial communities associated with Microcystis colonies collected on the nearby dates were clustered together. The bacterial clones from four clone libraries in different months were classified into 5, 12, 6 and 12 operational taxonomic units, most of which were affiliated with Gammaproteobacteria, Alphaproteobacteria and Bacteroidetes. Shift in dominance from pathogenic Aeromonas sp. to Shewanella sp. capable of remineralization of many organic materials was observed, and both species seemed to be associated with Microcystis colonies along with the bloom decline. These results indicated that the potential harmful effects of the Microcystis bloom on the safety of lake water during the decline period should be taken into account. [ABSTRACT FROM PUBLISHER]

The methods of X-ray diffraction (XRD) and ICP-AES are applied to analyzing the mineral composition of modern and fossil snail shells in Luochuan section and Xifeng section. The results show that the mineral phase of calcium carbonate in modern snail shells is aragonite, but for some fossil snail shells in certain layers of loess sequences, a part of aragonite is transformed into calcite. In Luochuan and Xifeng sections, the stratigraphic borderline of aragonite-calcite transformation appearing obviously is between L5 and L6. Under the earth surface condition, the aragonite-calcite transformation is influenced by the factor of temperature only in a long time scale. It seems that the pressure is not the factor influencing the aragonite-calcite transformation. The results also show that existing age of snail shells is possibly the dominant and principal factor for the aragonite-calcite transformation. To a certain extent, the degree of aragonite-calcite transformation in snail shell is controlled by the content of trace element, such as Mg2+. The trace element can improve the stability of snail shell aragonite and impede the process of aragonite transforming into calcite. [ABSTRACT FROM AUTHOR]

Volume expansion reactions involved in mineral–fluid interactions are linked to a number of geological processes, including silicate weathering, retrograde metamorphism, and mineralization. However, the effect of volume expansion on replacement reactions remains unclear. Here, we demonstrate that reactions associated with volume expansion during the replacement of pyrite by chalcopyrite involve two competing processes. The reaction is initially augmented because of the development of reaction-induced fractures in the pyrite. However, these fractures are subsequently filled by compacted products, which ultimately disrupts the contact and interaction between bulk fluids and the pristine pyrite surface. These competing processes indicate that replacement reactions are both augmented and inhibited by volume expansion reactions during pyrite replacement. [ABSTRACT FROM AUTHOR]

• Bayesian belief network approach and software statistical testing method are combined. • The quality of development activities and V&V activities of software is assessed. • Bayesian belief network provides a prior distribution of software reliability. • Test cases are generated based on probabilistic risk assessment. This study proposes an overall methodology that provides in-depth evidence on software reliability. It is used to quantitatively assess the reliability of nuclear power plant (NPP) safety-critical software for the incorporation of digital instrumentation and control systems into NPP probabilistic risk assessment (PRA). The methodology consists of three parts: (1) the relationships among the software development life cycle (SDLC) phases, the number of remaining faults in the software, and the probability of failure on demand (PFD) are modeled by a Bayesian belief network, which can provide a prior distribution of the software PFD; (2) a reliability model for the PFD is used to calculate the number of no-failure tests needed to meet the expected reliability target according to the prior distribution; (3) the software statistical testing (SST) based on PRA is used as a reliability validation test method to assess reliability, when the required no-failure tests are completed, it is considered that the software meets the expected reliability target. The main contribution of this methodology is that it fully considers the factors that affect software reliability, i.e. the quality of development activities and verification & validation (V&V) activities of the SDLC processes, software operational profile and software operational environment when assessing software reliability. This is done such that the methodology overcomes the subjectivity of separate quality assessments of the SDLC processes. It also solves the problem that occurs because an individual SST using an uninformative prior distribution is conservative. [ABSTRACT FROM AUTHOR]

Replacement of pyrite by copper-bearing sulfides is widespread in mineral deposits, with zonation of chalcocite, bornite, and chalcopyrite being a common result of this process. Copper occurs predominantly as Cu(I) in hydrothermal fluids, but the mechanistic details of reactions between pyrite and aqueous Cu(I) and their relevance to the zonation of Cu sulfides in hydrothermal deposits remain poorly understood, because of a lack of relevant experimental constraints. In this study, we investigated the reactions between pyrite and aqueous Cu(I) chloride solutions over a wide range of physicochemical conditions (100–250 °C; pH = 1–8; saturated vapor pressure). The experimental results show that Cu-bearing sulfides form at temperatures of >150 °C, and that pH exerts an important control on the mineralogy of the reaction products. In strongly acidic conditions (pH = 1.1), pyrite dissolution occurs; in acidic-to-neutral conditions (pH = 3.0–6.0), chalcopyrite and bornite are the main products; in weakly alkaline conditions (pH = 8.2), the replacement products are chalcocite and bornite. Chalcopyrite, bornite, and chalcocite generally occur in a zoned sequence outward from the pyrite reaction front to the bulk solution, and the replacement of pyrite by chalcopyrite is heterogeneous. In situ Raman observation and S isotope analyses suggest that pyrite replacement by chalcopyrite is a redox-coupled dissolution–precipitation reaction, with the oxidative dissolution of pyrite to form sulfate, generating the electrons that maintain the reductive replacement of pyrite by chalcopyrite. The sites of oxidative dissolution and reductive replacement can be spatially separated, but coupled by electron transfer. By contrast, the further replacement of chalcopyrite by bornite and chalcocite does not involve the oxidative dissolution of sulfur, but release of iron and H+, which could be promoted at higher pH. Notably, when the zonation of sulfides is established in a hydrothermal experiment of pyrite replacement by Cu(I) solution, gradients of H 2 S (or HS–), Cu(I), and Fe(II) are developed between the pyrite reaction front and bulk solution via diffusion through interstitial pore space. As such, the inner zones of chalcopyrite and bornite are not in equilibrium with the bulk solution as confirmed by thermodynamic calculations. The results imply that the zonation of Cu-bearing sulfides in mineral deposits records heterogeneous chemical environments, from the mineral interface- to the ore deposit-scale during dynamic mineralization processes. [ABSTRACT FROM AUTHOR]

The results of investigations into enrichment of precious metals in sphalerite and pyrite from the Maluntou epithermal gold deposit, China, are reported. The obtained data suggest intimate associations of Au- and Ag-bearing nanoparticles with chalcopyrite inclusions in sphalerite and pyrite. The origins of chalcopyrite inclusions involved different hydrothermal processes, including recrystallization-driven phase separation from parent chalcopyrite-sphalerite solid solutions and replacement of pre-existing pyrite in the presence of Cu-bearing fluids. The chalcopyrite blebs/lamellae follow sphalerite {111} planes, which define a shared sulfur layer for both chalcopyrite and sphalerite. This study indicates that mixing and boiling during the evolution of ore-forming fluids for the Maluntou deposit are key processes for the abnormal enrichment of precious metals in sphalerite and pyrite. The chalcopyrite micro/nano inclusions enhanced enrichment of precious metals in sphalerite provides new insights into the controls on the enrichment of precious metals in sulfides. [ABSTRACT FROM AUTHOR]

Hydrolysis of Sn is a pivotal step during the precipitation of cassiterite, the primary Sn-bearing mineral and thermodynamically stable Sn-oxide on Earth's surface. In this contribution, we investigated the reaction kinetics of Sn(IV) chloride hydrolysis by systematic experiments at temperatures of 6.4 °C to 28.6 °C. Experimental results show that the hydrolysis reactions of Sn(IV) chloride follow a first-order kinetics model, with rate constants (0.12 h−1 to 5.5 h−1) strongly controlled by temperature. Based on the obtained reaction constants at different temperatures and the Arrhenius equation, the activation energy of the Sn(IV) chloride hydrolysis reaction is calculated to be 26.05 ± 2.25 kcal/mol, indicating a surface-controlled reaction mechanism. Additionally, the Sn(IV) chloride hydrolysis rate increases with the ionic strength. No significant Sn isotope fractionation between aqueous Sn(IV) and the solid hydrolysis product was observed during the Sn(IV) hydrolysis experiments in this study. The activation energy data and Sn isotope behavior associated with Sn(IV) chloride hydrolysis may be used to better understand the behavior of Sn during various mineralization and weathering processes. • Determined Sn(Ⅵ) chloride hydrolysis rates under various temperatures and ionic strengths. • First report of activation energy for the Sn hydrolysis reaction. • Nanoparticles of Sn hydrolysis product for enhanced Sn transport in fluids. • Sn isotope fractionation during the Sn hydrolysis process is insignificant. [ABSTRACT FROM AUTHOR]

Soil microorganisms are considered the most effective decomposers of applied crop residues, but it is poorly understood which communities are primarily responsible for decomposition under different conditions. A pot experiment was conducted in a greenhouse to follow the cycling of C and N derived from maize ( Zea mays L.) residues labeled with both 13 C and 15 N to a subsequent winter wheat ( Triticum aestivum L.) crop and to soil pools under planting with winter wheat (+P) or an unplanted control (–P), both in soil maintained at field moisture capacities of 40% and 80%. Soil microbes involved in residue decomposition were investigated by 13 C phospholipid fatty acid ( 13 C-PLFA) analysis technique. At wheat maturity, a total of 68% of residue N was recovered in the +P treatments, in which 26% was recovered from wheat plants and another 42% from soil total N (TN), independent of the water regimes, while only 50% was recovered from TN in the –P treatments. More residue C was recovered as soil organic carbon in +P than –P treatments (33% vs. 27%), and the trend became more significant with soil moisture. In addition, the +P soil had 35–48% larger microbial biomass carbon (MBC) than the –P soil, and more residue C was recovered as MBC in +P than –P treatments (7% vs. 4%), suggesting the induced microbial utilization of the applied residues. The distribution of the residue-derived PLFA-C showed that only 16:1ω7c and 18:1ω7c had larger relative abundances in the +P than the –P soils, suggesting that they were mainly stimulated by the presence of wheat and that they may be the most important fatty acids to define the different recoveries of residue N and C between the planted and unplanted conditions. Our results demonstrate that the enhanced recovery of residue-C and -N by the presence of wheat plants was mainly from the induced microbial utilization of applied residues by altering the activities of specific microorganisms. [ABSTRACT FROM AUTHOR]

This study evaluated the structure, mineralogy, and chemical composition of ferromanganese micronodules in gravity core GC01 obtained from the eastern southwest Indian ridge using micro-Raman spectroscopy, WITec Alpha 300R confocal Raman spectroscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy, TESCAN integrated mineral analysis and electron microprobe analysis. The results revealed vernadite as the major crystalline phase in the ferromanganese micronodules. In addition, the micronodules contained small amounts of Fe oxyhydroxides and silicate minerals. All micronodules had low Mn/Fe ratios (~1), and their internal structures included concentric, clastic, dendritic, and foraminifera-like structures, among which the concentric and clastic structures were predominant. These characteristics suggest that micronodules are formed in an oxidizing environment via hydrogenetic processes. Volcanic materials and biological debris may act as "seeds" for micronodules, among which volcanic materials may serve as material sources. During water-rock interaction, volcanic clastics and biological debris react with seawater, and some cations (such as Ca2+, Na+, Mg2+) are leached out; Fe2+ and Mn2+ remain and generate Fe oxides or oxyhydroxides and Mn oxides which forms ferromanganese micronodules. Conclusively, the formation of ferromanganese micronodules in this study was controlled by a coupled dissolution-reprecipitation mechanism. • Structure, composition and formation of ferromanganese micronodules from the eastern Southwest Indian Ridge were studied. • Volcanic materials and biogenic debris acting as nucleus and material sources stimulate ferromanganese micronodule formation. • Interactions between volcanic minerals/biogenic debris and seawater was controlled by coupled dissolution-reprecipitation. [ABSTRACT FROM AUTHOR]

• The built-in self-test method for nuclear power plants safety-critical FPGA-based system is proposed. • The partition strategy of built-in self-test simplifies the test structure. • The built-in self-test method improves the self-diagnosis coverage and reduces the test effort. • An FPGA-Based Reactor Trip System built-in self-test logic example is provided. Field-programmable gate arrays (FPGAs) are being widely used in the instrumentation and control (I&C) systems of nuclear power plants (NPPs). However, FPGAs have the possibility of failure, resulting in the reliability not being fully guaranteed; therefore, some methods are required to evaluate and verify their reliability. The built-in self-test (BIST) method is a technology that implants relevant functional circuits into another circuit during design to provide self-test functions. It has many advantages over external test devices. For this study, the FPGA-based reactor protection subsystem of the CPR1000 NPP was selected as the test object. This paper presents the principle of system partition, the main objective of which is to reduce the test time and provide convenience for subsequent modifications; then, we use the BIST method and build the BIST architecture to test each input signal channel as a black box. For several common failures, 100% diagnostic coverage can be obtained, which improves the reliability of a protection system. BIST can be used as a supplement to external tests; it can reduce the test time, reduce testing costs, and solve many problems that cannot be solved using external tests, such as the lack of interfaces. The research results provide theoretical and technical references for the application and review of FPGA-based applications in NPP safety–critical systems. [ABSTRACT FROM AUTHOR]

Pyrrhotite is one of the common ore minerals in Cu-Ni sulphide deposits, but only monoclinic pyrrhotite is ferromagnetic at room temperature. X-ray and EPA analyses reveal that most pyrrhotite forming sideronitic texture in the Hongqiling Cu-Ni sulphide deposit is monoclinic, but that in the massive ore is a mixture of monoclinic and hexagonal pyrrhotites. Differential thermal and magnetic-thermogravimetric analyses of massive ore indicate a magnetic transition and heat absorption at 323°C, suggesting that this temperature is the thermomagnetic and phase transition point of pyrrhotite. For massive pyrrhotite ores heated at 400°C for 30 h and then quenched by cool water, the monoclinic pyrrhotite (hpo) transforms completely into the hexagonal pyrrhotite (hpo). However, all the pyrrhotites resulting from slow cooling of the sample in air are hpo. These results indicate that transformation between hpo and hpo depends upon the cooling rate. Therefore, massive ores in this deposit might have been formed via rapid cooling of ore melts. On the other hand, it is significant to study the effect of the ratio of the magnetite in total ores on the genesis of magmatic Cu-Ni suphide deposits. [ABSTRACT FROM AUTHOR]

• First paired δ7Li data of different components were reported for the cap carbonates. • Marine clay authigenesis is intense during the late neoproterozoic. • δ7Li data indicate highly congruent weathering in the Marinoan aftermath. The termination of the Cryogenian period marks a transition from an extreme ice- to a greenhouse climate, likely initiated by increased atmospheric CO 2 , however uncertainties persist on continental weathering regarding this climate transition. Here we present paired lithium isotope data from carbonate (δ7Li carb) and carbonate-hosted silicate (δ7Li sili) components of the Marinoan cap carbonates to constrain C and Si cycles in the deglacial period. We find that the silicate component of cap carbonates is dominated by marine authigenic clays with minor contributions from terrestrially detrital materials and oxides. Built from δ7Li sili data, large variations of seawater δ7Li suggest a heterogeneous marine Li reservoir due to a stratified ocean in the deglacial period. Overall, widespread clay authigenesis and low seawater δ7Li values indicate active carbon-silicon cycling and congruent silicate weathering due to warm climate and exposure of fresh rock surface in the Marinoan aftermath, which promotes the deposition of cap carbonates and stabilization of Earth's surface environment. [ABSTRACT FROM AUTHOR]

DNA-based stable isotope probing (DNA-SIP) was employed to establish direct link between methane oxidation activity and the taxonomic identity of active methanotrophs in three rice field soils from Jian-San-Jiang (one baijiang origin soil, JB and one meadow origin soil, JM) and Qing-An (meadow origin soil, QA) districts in Northeastern China. Following microcosm incubation under 1% v/v13CH4 condition, soil organic 13C atom percent significantly increased from background 1.08 to 1.21% in average, indicating the biomass synthesis supported by methanotrophy. Real-time PCR analysis of methanotroph-specific biomarker pmoA genes of the buoyant density for DNA gradient, following the ultracentrifugation of the total DNA extracted from SIP microcosms, indicated an enrichment of methanotroph genomes in 13C-labeled DNA. It suggested propagation of microbial methane oxidizers in soils. High-throughput sequencing of 16S rRNA and pmoA genes from 13C-labeled DNA further revealed a diverse guild of both type I and II methanotrophs in all three soils. Specifically, Methylobacter-affiliated type I methanotrophs dominated the methanotrophic activity in JB and JM soils, whereas Methylocystis-affiliated type II methanotrophs dominated QA soil. This implied the physiological diversification of soil methanotrophs that might be due to constant environmental fluctuations in paddies. [ABSTRACT FROM AUTHOR]

• We investigate the individual preferences and check-in behavior in LBSNs. • A POI recommended model that considered relationship strength for places is proposed. • The model divides social links and provides information for POIs recommendations. Point of interest (POI) recommendation systems have drawn the attention of researchers in multiple domains, particularly location-based social networks (LBSNs). However, owing to barriers in data collection and information classification, most existing systems lack adaptability for users with varied relationship circles, which leads to unsatisfactory recommendation results. In this study, a model that considers user relationship strength is provided based on a data-driven method for improving the POI recommendations. It defines the user relationship according to an analysis of the user's check-in behavior. The user's social links are then embedded in the spatiotemporal model for POI recommendations. The effectiveness of this dynamic recommendation model is demonstrated by comparing six state-of-art POI recommendation techniques on three real-world datasets. The experiment results found significant correlations between the user relationship strength and check-in locations, which improved the model performance. Conceptually, this study supports the hypothesis that user relationship traits help explain personal preferences in LBSN usage and places visited. This study provides an intelligent social network system that provides real-time, location-aware recommendations for retailers. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance (AMR) is a major threat to public health worldwide. It is a promising way to improve appropriate prescription by the review and stewardship of antimicrobials, and Post-Prescription Review (PPR) is currently the main tool used in hospitals. Existing methods of PPR typically focus on the dichotomy of antimicrobial prescription based on binary classification which, however, is usually a multi-label classification problem. Moreover, previous research did not explain the causes beneath the inappropriate antimicrobial used in the clinical setting, which could be practically important for problem location and decision improvement. In this paper, we collected antimicrobial prescriptions and related data from clean surgery in a hospital in northeastern China, and proposed a Multi-label Antimicrobial Post-Prescription Review System (MAPRS). MAPRS first uses NLP techniques to process unstructured data in prescriptions and explores the value of clinical record text for solving medical problems. Then, Classifier Chains are used to deal with multi-label problems and fused with machine learning algorithms to construct a classifier. At last, a SHAP explanation module is introduced to explain the inappropriate prescriptions. The experimental results show that MAPRS could achieve great performance in a challenging six-category multi-label task, with a subset accuracy of 90.7 % and an average AUROC of 94.3 %. Our results can help hospitals to perform intelligent prescription review and improve the antimicrobial stewardship., Competing Interests: Declaration of competing interest All authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The reaction of ubiquitous clay is related to the global cycle of the key metals, but the relationship between the Li occurrence interface and the sedimentation in the Li cycle remains unclear. We investigated the atomic interface arrangement of Li-montmorillonite (Li-Mt) during low-temperature water-rock reactions and Li migration. The results show that, in Cl-rich systems, deprotonation and exposure of Na adsorption sites cause Li enrichment and O pairing, which lead to the weakening of the shielding effect of Mt on anions and the formation of a Mt-Li-Cl atomically interfacial arrangement. Only up to 20.3% of the Li is contained in the atomic interface of Li-Mt. In F-rich system, the dehydroxylation of F paired with Al in octahedral sites causes Li accumulation via local crystallization of LiF, and co-complexation of F and Li forms a Mt(Al)-F-Li atomic interface, in which up to 46.8% of the Li is enriched by the Mt. The participation of F and Cl in the complexation intensifies lattice collapse of the Li-Mt edge. The sedimentation velocity decreases with the smaller particle size affected by the Li loading. Lithium leached from igneous rocks serves as the marine Li source, which contributes up to 99.8% and 99.5% of the Li in Cl- and F-rich systems, respectively. The response of Mt(OH) to Li migration with a time accumulating effect may make an important regulatory of oceanic pH by either acidification or alkalization.

Methane-oxidizing bacteria (MOB) have long been recognized as an important bioindicator for oil and gas exploration. However, due to their physiological and ecological diversity, the distribution of MOB in different habitats varies widely, making it challenging to authentically reflect the abundance of active MOB in the soil above oil and gas reservoirs using conventional methods. Here, we selected the Puguang gas field of the Sichuan Basin in Southwest China as a model system to study the ecological characteristics of methanotrophs using culture-independent molecular techniques. Initially, by comparing the abundance of the pmoA genes determined by quantitative PCR (qPCR), no significant difference was found between gas well and non-gas well soils, indicating that the abundance of total MOB may not necessarily reflect the distribution of the underlying gas reservoirs. 13 C-DNA stable isotope probing (DNA-SIP) in combination with high-throughput sequencing (HTS) furthermore revealed that type II methanotrophic Methylocystis was the absolutely predominant active MOB in the non-gas-field soils, whereas the niche vacated by Methylocystis was gradually filled with type I RPC-2 (rice paddy cluster-2) and Methylosarcina in the surface soils of gas reservoirs after geoscale acclimation to trace- and continuous-methane supply. The sum of the relative abundance of RPC-2 and Methylosarcina was then used as specific biotic index (BI) in the Puguang gas field. A microbial anomaly distribution map based on the BI values showed that the anomalous zones were highly consistent with geological and geophysical data, and known drilling results. Therefore, the active but not total methanotrophs successfully reflected the microseepage intensity of the underlying active hydrocarbon system, and can be used as an essential quantitative index to determine the existence and distribution of reservoirs. Our results suggest that molecular microbial techniques are powerful tools for oil and gas prospecting.

Due to strong industrial demand for Li, Li-bearing montmorillonite (Li-Mt) deposits are a focus for exploration, but the Li enrichment mechanisms in such deposits are unclear. In this study, adsorption experiments and mineralogical analyses were used to investigate the water-rock reactions at different Li concentrations, temperatures, durations, and pH conditions, in order to reveal the Li enrichment mechanisms in F- and Cl-rich systems. Our results suggest that water-rock reactions are different in the two halogen systems. The reaction in the LiCl-Mt system involves deprotonation, whereas dehydroxylation occurs in a LiF-Mt system. Lithium is adsorbed or exchanges with interlayer cations in Mt. Adsorption forms a monolayer that is consistent with the Langmuir model in a LiCl system. Lithium is adsorbed in multi-layers in Mt in a LiF system. For a given Li concentration, the adsorption capacity of the LiF-Mt system is 2.8 times greater than that of the LiCl-Mt system. The pH has a weaker effect in the LiCl-Mt system than in the LiF-Mt system. Furthermore, Li adsorption is hindered at very high or low pH in a LiF system. The chemical shift of Li is -0.2 ppm (±0.1 ppm) in a nuclear magnetic resonance (NMR), which indicates that Li occurs as inner-sphere complexes in the pseudo-hexagonal cavity in Mt. Based on a CaCl 2 leaching experiment, >50% (up to 97.94%) of the Li can be easily exchanged out of the Mt. The residual Li in the inner-sphere is the key to metallogenesis of Li-Mt deposits. Therefore, the grade of ion adsorption-type Li deposits is determined by the exchangeable Li.