Search Results (54)

Biomineralization in plant tissues is a widespread process accompanied by carbon fixation in biogenic minerals. This study aimed to evaluate the effect of CaCO₃ application to soil on the formation and localization of biominerals in the pericarp of fruits of Buglossoides arvensis (L.) I.M. Johnst., as well as on the accumulation of carbon in minerals. B. arvensis seeds were sown in the soil treated with CaCO₃ at concentrations of 0.0 (0 Ca), 2.5 (2.5 Ca), 5.0 (5 Ca), 7.5 (7.5 Ca), and 10.0 (10 Ca) t ha⁻¹. As a result of CaCO₃ application, on average across all treatments, the increase in soil pH was 30%, and the calcium and silicon content in the soil increased by 60 and 39%, respectively. The fruit weight was 4, 28, 42, and 21% higher in 2.5 Ca, 5 Ca, 7.5 Ca, and 10 Ca plants than in 0 Ca plants. Scanning electron microscopy analysis revealed the presence of silica and calcium carbonate in the pericarp of B. arvensis fruits, but showed no significant differences in the localization of biominerals in the pericarps between the treatments. The content of biosilica (phytoliths) was lower in 2.5 Ca, 5 Ca, 7.5 Ca, and 10 Ca plants than in 0 Ca plants, respectively, by 11, 14, 25, and 19%. The content of organic carbon occluded in a unit mass of phytoliths was, on average, 49% higher in treated than in 0 Ca plants. The content of carbonate fraction in fruits was 13, 14, 20, and 21% higher in 2.5 Ca, 5 Ca, 7.5 Ca, and 10 Ca plants than in 0 Ca plants, reflecting the effect of soil calcium levels on carbonate content in B. arvensis pericarp. Thus, in the pericarp of fruits, the ratio of silica to carbonates changed towards a decrease in silica content and an increase in carbonate content as the availability of calcium in the soil increased. In summary, B. arvensis responds to increased soil calcium and soil pH by increasing carbon accumulation in biominerals formed in fruit pericarps, supporting the potential for variability in plant biomineralization characteristics under changing growth conditions. Full article

Understanding the impact of ash on nanopore heterogeneity is crucial for evaluating deep coalbed methane (CBM) reservoirs. This study investigates the Benxi Formation coal Seam 8 in the Nalinhe Block, Ordos Basin. Based on proximate analysis, samples were categorized by ash yield (A_ad%). Pore structures were characterized using low-temperature nitrogen adsorption (<2 nm) and carbon dioxide adsorption (2–100 nm). Fractal theory was employed to quantitatively assess pore heterogeneity across different scales. The results indicate that ash content significantly constrains the development of both micropores (<2 nm) and mesopores (2–100 nm), with the most pronounced effect on micropores in the 0.3–0.6 nm range. Ash, primarily derived from kaolinite, occludes pores, reducing pore volume and specific surface area, thereby diminishing methane adsorption capacity. Notably, pore heterogeneity is found to decrease with increasing pore volume. These findings provide valuable insights for the efficient exploration and development of deep CBM resources in the Nalinhe and Suide blocks. Full article

Background: Phytolith-occluded carbon (PhytOC) is highly stable and constitutes an important long-term carbon pool in agroecosystems, particularly in nutrient-poor, sandy soils. Silicon (Si) uptake by plants is strongly associated with phytolith formation, with Si accounting for up to 90% of phytolith composition. However, the role of Si fertilization in enhancing PhytOC sequestration under field conditions remains insufficiently quantified. Integrated fertilization strategies supporting sustainable development in climate-resilient agriculture can enhance biological carbon sequestration by increasing phytolith formation and phytolith-occluded carbon accumulation, thereby improving the carbon sink potential of cereal-based agroecosystems. Methods: A field experiment was conducted to assess phytolith and PhytOC accumulation in barley biomass under different fertilization regimes, including foliar silicon application using the liquid immune stimulant Optysil and compost fertilization. Phytolith content was determined separately for grain and straw, and PhytOC stocks were converted into CO₂ equivalents to estimate annual sequestration potential. Results: Barley produced substantial amounts of phytoliths, with consistently higher concentrations in straw than in grain. Phytolith content ranged from 18.46 to 21.28 mg g⁻¹ DM in grain and from 27.89 to 38.97 mg g⁻¹ DM in straw. Depending on fertilization treatment, annual carbon sequestration through PhytOC ranged from 16.86 to 55.17 kg CO₂ equivalents ha⁻¹. Foliar silicon application increased PhytOC accumulation in barley biomass by up to threefold compared with treatments without Si. Conclusions: The results demonstrate that optimizing silicon fertilization can substantially enhance carbon sequestration in cropping systems via phytolith formation and PhytOC stabilization. Given the dominant role of cereals in crop rotations and their high phytolith-producing capacity as monocotyledonous plants, Si-mediated PhytOC sequestration represents a promising pathway for strengthening soil carbon storage and contributing to climate change mitigation. Full article

The Permian Wargal Formation of the western Salt Range preserves a shallow marine carbonate-ramp succession, in which heterogeneity reflects coupled depositional architecture, facies-selective diagenesis, and deformation-related structural compartmentalisation of the Wargal interval. This study integrates balanced restoration with stratigraphic logging, microfacies analysis, paragenetic reconstruction, and quantitative pore-network topology to evaluate how stratigraphic packaging and diagenetic overprint govern connected pathway development within a structurally partitioned fold–thrust setting. Balanced restoration of a representative transect yields 1.1336 km of minimum tectonic shortening (18.7%) and indicates shortening shared between thrust slip and distributed folding, providing an admissible geometric framework for assessing compartmentalisation. The Wargal succession is ~130 m thick and organised into three carbonate packages bounded by laterally persistent argillaceous marker intervals (~21–23 m and ~98–105 m), with grain-supported shoal to shoal-margin facies dominating intervening units. Diagenesis is strongly facies-selective; grain-supported microfacies record progressive calcite cementation that occludes pore throats, whereas mud-supported facies retain microporosity but are preferentially modified by neomorphism, compaction, and pressure-solution fabrics. Image-based analysis of 20 thin-section fields of view shows that pore connectivity varies systematically among microfacies and that a connectivity-weighted index ($I_{\mathrm{conn}}$) covaries more closely with skeleton-derived connectivity than with segmented areal porosity (${\varphi }_{2D}=0.124$–9.750%). The combined results quantify the decoupling between pore volume and connectivity and provide a basis for predicting reservoir-quality evolution from facies architecture, diagenetic sequence, and structural segmentation, with direct relevance to subsurface characterisation of marine carbonate successions in hydrocarbon systems. Full article

Vehicle detection is a core task in smart city perception management and an important technical support for sustainable urban development and intelligent transportation optimization. In high-resolution unmanned aerial vehicle (UAV) remote sensing images, it faces challenges such as variable target scales, severe occlusion, and difficulty in modeling long-range dependencies. To address these issues, this study proposes the MCViM-YOLO algorithm, which integrates the local perception advantage of convolution with the global modeling capability of the state space model (Mamba). Based on YOLOv12, the algorithm reconstructs the neck network: it introduces the Mix-Mamba module (parallel multi-scale convolution and selective state space model) to simultaneously capture local details and global spatial dependencies, adopts the dual-factor calibration fusion module (DCFM) to adaptively fuse heterogeneous features, and employs a dual-branch attention detection head (DADH) to optimize the prediction of difficult samples (e.g., occluded, small-scale vehicles). Experiments on the VEBAI dataset demonstrate that our proposed model achieves an mAP@0.5 of 92.391% and a recall rate of 86.070%, with a computational complexity of 10.41 GFLOPs. The results show that the proposed method effectively improves the accuracy and efficiency of vehicle detection in complex remote sensing scenarios, provides technical support for traffic flow monitoring, low-carbon urban planning, and other sustainable applications, and offers an innovative paradigm for the deep integration of CNN and state space models with both theoretical research value and engineering application prospects. Full article

As a key freshwater wetland in the Beijing–Tianjin–Hebei core area, Baiyangdian Lake’s ecological health is strategically significant for regional ecological security, prompting this study to explore how sediment phosphorus forms drive its phytoplankton communities. The research adopted sequential extraction technology, morphological identification, and multivariate statistics in Baiyangdian Lake. Results showed sediment phosphorus was dominated by highly active exchangeable phosphorus (Ex-P, ~60%, with higher levels around villages of lake center and western areas), with occluded phosphorus (Oc-P, ~23%) as the second most abundant form. Ex-P was the core factor shaping phytoplankton communities, directly increasing biomass density (r = 0.38, p < 0.05) and explaining 17.92% of community variation. Bacillariophyta was the dominant group (43.3%), while calcium-bound phosphorus (Ca-P) maintained diversity and aluminum-bound phosphorus (Al-P) inhibited evenness (r = −0.35, p < 0.05). Active phosphorus directly affected, and inactive phosphorus indirectly regulated, phytoplankton patterns, clarifying the unique phosphorus structure of northern carbonate-type lakes and filling research gaps. It is suggested to include Ex-P and Ca-P in aquatic ecological monitoring and prioritize sediment passivation and riparian restoration in high-Ex-P areas to mitigate algal bloom risks. Full article

To identify the principal controls on gas-bearing property heterogeneity in tight reservoirs of the Shaximiao Formation in the southwestern Sichuan Basin, this study systematically examines pore structure characteristics and their influence on reservoir quality through an integrated approach incorporating cast thin sections, X-ray diffraction (XRD), high-pressure mercury injection (HPMI), and parameters such as homogeneity and variation coefficients. The research has indicated that the following findings: (1) The reservoir lithology in the study area is predominantly lithic arkose, with pore types dominated by residual intergranular pores and intragranular dissolution pores, and pore-throat radii ranging from 5 nm to 1 μm. (2) The disparity in reservoir quality is attributed to two primary factors. Firstly, diverse sediment provenance directions and varying mineral compositions directly influence the internal pore structure of the reservoirs. Secondly, differences in diagenetic minerals lead to heterogeneity in pore space development. Specifically, early carbonate cementation in the Pingluoba reservoir occluded porosity, resulting in poor physical properties. In the Yanjinggou reservoir, clay mineral cementation and pore-filling activities significantly reduced reservoir quality. In contrast, the presence of chlorite coatings in the Baimamiao and Guanyinsi reservoirs helped preserve primary porosity, contributing to superior reservoir properties. (3) The variation in gas content between different gas reservoirs is primarily attributed to differences in reservoir heterogeneity on a planar scale, whereas the gas content variation within different intervals of the same gas reservoir is controlled by differences in pore structure among various sand units. Furthermore, gas content heterogeneity within the same interval of a single reservoir results from variations in sand body thickness and connectivity. Full article

This study focuses on the clastic reservoir in the first member of Yaojia Formation within Qijia-Gulong Sag, Songliao Basin. The results indicate that the reservoir in the study area develops within a shallow-water delta sedimentary system. The dominant sedimentary microfacies comprise underwater distributary channels, mouth bars, and sheet sands. Among these, the underwater distributary channel microfacies exhibits primary porosity ranging from 15.97% to 17.71%, showing the optimal reservoir quality, whereas the sheet sand microfacies has a porosity of only 7.45% to 12.08%, indicating inferior physical properties. During diagenesis, compaction notably decreases primary porosity via particle rearrangement and elastic deformation, while calcite cementation and quartz overgrowth further occlude pore throats. Although dissolution can generate secondary porosity (locally up to 40%), the precipitation of clay minerals tends to block pore throats, leading to “ineffective porosity” (permeability generally < 5 mD) and overall low-porosity and low-permeability characteristics. Carbon–oxygen isotope analysis reveals a deficiency in organic acid supply in the study area, restricting the intensity of dissolution alteration. Reservoir quality evolution is dominantly governed by the combined controls of sedimentary microfacies and diagenesis. This study emphasizes that, within shallow-water delta sedimentary settings, the material composition of sedimentary microfacies and the dynamic equilibrium of diagenetic processes jointly govern reservoir property variations. This insight provides critical theoretical support for understanding diagenetic evolution mechanisms in clastic reservoirs and enabling precise prediction of high-quality reservoir distribution. Full article

Collapsible loess poses significant geotechnical risks due to its metastable structure and water sensitivity, while conventional stabilization methods often lack sustainability. This study investigates the synergistic effects of microbial-induced carbonate precipitation (MICP) and modified biochar (MBC) to enhance loess engineering properties. Controlled experiments evaluated hydraulic conductivity, shear strength, and stress-strress–strain behavior under varying MBC content (0–8%), cementation reagent concentration (0.5–1.5 mol/L), and confining pressures (50–400 kPa), and complemented by microstructural characterization via scanning electron microscope (SEM). Results demonstrate that MBC (4–6%) optimizes calcium carbonate distribution by providing nucleation sites, reducing hydraulic conductivity by 72% and increasing shear strength by 52% when compared with untreated loess. Elevated confining pressures (200–400 kPa) transformed brittle failure into ductile behavior through particle interlocking, with peak strength quadrupling under 400 kPa. SEM analysis revealed MBC stabilizes hierarchical pore networks: macropores sustain microbial activity, while mesopores are occluded by CaCO₃-MBC composites, sequestering ionic byproducts to mitigate efflorescence. The optimal combination (6% MBC, 1.0 mol/L reagent, 200 kPa confinement) achieved 85% of maximum strength gain at reduced reagent cost, balancing performance and sustainability. Full article

Phytolith carbon sequestration has been recognized as an important mechanism for long-term carbon sequestration in forest ecosystems. Conducting relevant research in cold temperate regions that are sensitive to climate change can reveal their unique mechanisms as a stable and long-term carbon pool, fill key blind spots in global carbon cycling models, and provide necessary scientific support for developing climate-resilient ecological strategies and carbon neutrality pathways. In this study, we focused on the Larix gmelinii forest ecosystem and investigated the latitudinal spatial characteristics of soil phytolith and phytolith-occluded carbon (phytOC) in Eastern China. We analyzed the factors that influenced their accumulation and assessed their storage potential across different climatic zones. Our findings revealed an exponential increase in soil phytolith content with increasing latitude in Eastern China. Additionally, the content of soil phytoliths in tropical and subtropical forests was significantly lower than in the cold temperate forests. It was also found that soil phytOC content increased linearly with latitude and was significantly higher in cold temperate zones than in the other climatic zones. The order of soil phytOC storage was tropical (0.23 t ha⁻¹) < middle temperate (0.24 t ha⁻¹) < subtropical (0.27 t ha⁻¹) < cold temperate (1.20 t ha⁻¹). Soil phytolith and phytOC content were significantly negatively correlated with temperature and precipitation. pH, organic matter, and nutrients of soil significantly influenced the formation and accumulation of soil phytoliths. It can provide a scientific basis for the quantitative evaluation of forest soil carbon pool. Full article

Field experiments spanning five years were conducted to convert barren mountainous land into apple orchards, testing five phosphorus (P) fertilization schemes: no inorganic P (NP0K), superphosphate (FP), water-soluble inorganic P (WSF), superphosphate with alkaline soil conditioner (SC), and superphosphate with grass interplanting (GC). Fertilizer solubility and soil pH were found to significantly impact P leaching and accumulation. Among the schemes, WSF exhibited the highest P leaching loss (3.65–3.87%), while SC (2.17–2.79%) and GC (2.79–3.25%) minimized such losses. As soil pH declined over time, aluminum P (Al-P) replaced calcium P (Ca-P) as the dominant inorganic P fraction, while occluded P (O-P) increased, resulting in reduced P bioavailability. Soil organic carbon (SOC) and acid phosphatase activity positively influenced inorganic P fractions, whereas prolonged orchard establishment decreased fixed inorganic P content. Microbial P cycling genes were less abundant and showed negative correlations with soil nitrate-N, electrical conductivity, available P (Olsen P), and SOC. These findings highlight that grass interplanting with superphosphate (GC) is an optimal strategy to minimize phosphorus leaching, enhance soil phosphorus bioavailability, and reduce environmental risks, making it a sustainable approach for orchard management. Full article

To discriminate the transport characteristics of residue-derived carbon (C_res) from soil native carbon (C_soil) in black soil with split nitrogen application, a 540-day incubation study was conducted with four treatments: Control (unamended soil), R (soil + residue), RN1 (soil + residue + one-time application of nitrogen fertilizer), and RN3 (soil + residue + three-time application of nitrogen fertilizer). The total soil organic carbon (TOC) of the incubated soil was separated into three fractions: light fraction (LF), occluded-particulate organic matter fraction (OPOM), and heavy fraction (HF). The results showed that the TOC content was significantly higher in the RN1 and RN3 (averaging 20.77 g/kg) than in the R (18.43 g/kg) and Control (19.03 g/kg) after 540 days. Nitrogen fertilization significantly increased the residual rate of HF−C_res by 11.75% (p < 0.05), and the RN3 treatment significantly increased the residual rate of OPOM−C_res by 18.84% (p < 0.05) and reduced the loss rate of LF−C_soil by 77.01% (p < 0.05) compared with the R treatment. The soil catalase activity declined continuously along with incubation and was higher in the RN3 treatment than in the RN1 treatment after 180 days. The correlation analysis showed that the LF−C_soil and −C_res, as well as the HF−C_soil and catalase activity, were the main contributors to the TOC. Conclusively, nitrogen application, especially split nitrogen application, could stimulate the ability of soil to retain exogenous carbon and preserve native carbon. Full article

Lime application is an effective measure for improving rice yield and alleviating soil acidity, whereas its long-term effects on the sequestration and stability of soil organic carbon (SOC) remain unclear in paddy fields. Here, we report on the first 10-year long-term experiment to examine the impact of lime application on the quantity and quality of SOC in an acidic paddy field with double rice cropping. Lime was applied every 4 years with and without rice straw incorporation. Size and density fractionation and solid-state ¹³C nuclear magnetic resonance spectroscopy were employed to examine the physical fractions and chemical composition of SOC, respectively. The results showed that lime application had no significant effect on either the total SOC concentration or stocks. Compared to the non-lime control, lime application led to a 60.0% decrease in the free particulate organic carbon (fPOC) concentration but a significant 17.9% increase in the concentration of occluded particulate organic carbon (oPOC) while reducing the concentration of mineral-associated organic carbon (MAOC) by 5.3%. Chemical composition analyses revealed a 5.1% reduction in the content of alkyl carbon (C) and a 6.8% decrease in the ratio of Alkyl C to O-Alkyl C. Lime application and straw retention had a significant interactive effect on the composition of SOC. Under straw removal, lime application increased the oPOC concentration by 56.6%, while no significant effect was observed under straw return. Lime application had no significant effect on the MAOC concentration under straw removal, whereas it reduced this concentration by 9.8% under straw return. Under straw removal, lime application reduced the proportion of Alkyl C by 9.5%, while no significant effect was observed under straw return. Therefore, we conclude that although the total SOC stocks are not altered, long-term lime application reduces the content of MAOC and Alkyl C in the acidic paddy soil, suggesting that long-term liming may reduce SOC stability. Full article

The area of Cunninghamia lanceolata forests in China is expansive, the soil PhytOC(phytolith-occluded organic carbon) stock of Cunninghamia lanceolata forests is a vital carbon reservoir on the global scale. Soil from the Cunninghamia lanceolata forests was collected, and the soil physicochemical indexes and phytoliths and PhytOC content were measured to explore the accumulation characteristics of PhytOC in the 0–10, 10–20, and 20–30 cm soil layers at different stand ages. The results are as follows: (1) soil phytolith content (11.98–32.60 g·kg⁻¹), PhytOC content (0.48–1.10 g·kg⁻¹), PhytOC/TSOC (1.90%–6.93%), soil PhytOC stock (0.446–1.491 t·hm⁻²), and mature forest > middle–aged forest > Huitou-sha forest > young forest. The soil PhytOC accumulation was significantly affected by stand age. Huitou-sha is not an advantageous afforestation way of Cunninghamia lanceolata. (2) the soil physicochemical properties and stand conditions had significant effects on soil PhytOC accumulation. High–silicon, carbon-rich, acidic soil environment and appropriate thinning are conducive to phytolith formation and PhytOC sequestration. (3) the accumulation potential of soil PhytOC in the Cunninghamia lanceolata forest is relatively large, and its importance as a forest carbon sink cannot be ignored. Soil PhytOC stock in Cunninghamia lanceolata forests of different stand ages will lay a foundation for accurate estimation of forest carbon sink. Full article

Microplastic (MP) pollution, an emerging global change factor, disturbs the ecosystem functioning. Inland wetlands, providing important ecosystem services, might be an important sink for MPs. Understanding the distribution, source, and fate of MPs in inland wetland ecosystems is a prerequisite for developing an effective management strategy. Here, different types of inland wetlands, including the river wetland, constructed wetland, and lake wetland, were selected to explore the pollution patterns of MPs therein. Results showed that the abundance of MPs in wetland soil ranges from 532 to 4309 items/kg. Transparent, fibers, and polyethylene terephthalate were the most common color, shape, and polymer type of MPs, respectively. The constructed wetland in this study did not significantly remove MPs. The lake wetland was one of the main sinks for MPs in the inland wetland ecosystem and had accumulated large amounts of MPs. In addition, MP characteristics and cluster analyses showed that aquaculture, agricultural cultivation, and domestic waste were the most important sources of MPs in the study area. The occluded particulate organic carbon content in this study was related to MP abundance. In conclusion, this study reveals the pollution characteristics of MPs in the special inland wetland ecosystem of river-constructed-lake wetlands, which would help to better understand the distribution and source of MPs in inland wetlands and have implications for the subsequent pollution control and ecological restoration of inland wetlands. Full article