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81. 题目: More than just spectra: the synergistic role of pH in advancing hyperspectral SOC prediction
文章编号: N25120902
期刊: Catena
作者: Mahdis Khorram, Debankur Sanyal, Saurav Kumar
更新时间: 2025-12-09
摘要: Soil Organic Carbon (SOC) is a fundamental indicator of soil health and a key component of global carbon cycling, particularly in arid and semi-arid regions where it is highly vulnerable to mineralization to carbon dioxide (CO2). Hyperspectral imaging (HSI) offers a non-destructive approach for SOC prediction by capturing detailed spectral signatures across the VNIR and SWIR regions. In this study, we developed a comprehensive modeling framework combining laboratory-acquired HSI data with fractional-order derivatives (FODs), multidimensional spectral indices (2D/3D), and the auxiliary use of soil pH, an often overlooked, easily measured, but moderately correlated variable that significantly enhanced model performance. Using 103 dried and sieved soil samples, the optimal feature set that included FOD-based 3D indices and pH achieved the highest test performance (R2 > 0.85), confirming the synergistic relation between advanced spectral transformations and physicochemical soil properties. To assess the generalizability of our findings, we simulated Maxar-like multispectral bands from the hyperspectral data. Despite the reduced spectral resolution, the simulated Maxar bands achieved an R2 of approximately 0.65, based on simulations conducted under idealized laboratory conditions with a limited sample size. Notably, Partial Least Squares Regression (PLSR) performed best across our hyperspectral models, in line with its strengths for high-dimensional, collinear spectra in small-sample settings. This study provides a best-case benchmark for translating laboratory spectroscopy to satellite-like bands and indicates potential for scalable SOC mapping pending validation with real imagery and ancillary layers.

82. 题目: Response of SOC stocks in Northeast China to climate warming and precipitation changes
文章编号: N25120901
期刊: Catena
作者: Zhuyuan Qin, Huanjun Liu, Xiangtian Meng, Baicheng Du, Depiao Kong, Ying Zhan
更新时间: 2025-12-09
摘要: Changes in temperature and precipitation strongly affect soil organic carbon (SOC) stock dynamics, which in turn affects the climate feedback process, but the mechanism of the compound effects remains unclear. In this study, we integrated the spatio-temporal substitution method and meta-analytical framework, used a Bayesian optimized XGBoost model to predict the spatio-temporal dynamics of SOC with high accuracy, combined structural equation modeling and partial dependency plots to analyze the driving mechanisms, and simulated the future scenarios under the gradient changes of temperature (TAVG: 0–4 °C) and precipitation (PR: −50 % to + 50 %). The results show that: (1) the regional SOC stock fluctuated in a “decrease-increase–decrease” phase between 1985 and 2020, with a net loss of 5.38 Mg C/ ha, and the area of the carbon loss zone is nearly twice as large as the area of the positive change; (2) climatic factors contributed to 50 % of the SOC variability, with TAVG as the core negative driver and there is a critical threshold of −1 °C: below the threshold, low temperatures inhibit microbial activity and promote carbon accumulation, above the threshold, cascading degradation is triggered (warming → degradation of parent material → weakened carbon sequestration by vegetation → reduction of carbon inputs) to amplify the SOC loss, and PR mitigates the loss through multi-pathway synergistic effects; (3) warming dominates the systematic decline of SOC in future scenarios (the loss increases significantly for every 1 °C warming), and the synergistic effect of high temperature and drought increases the SOC loss (TAVG = 4 °C + PR = −50 % results in 26.89 % loss), and the compensatory effect of increased precipitation diminishes with warming (PR + 50 % at TAVG = 4 °C only increases SOC by 0.70 %); (4) ecosystem response shows a gradient: cropland is the most sensitive (28.83 % loss from warming and drying), forests are the most stable (reliant on litter cover buffer), and wetlands were highly dependent on water (PR + 50 % offset the negative effect of 4 °C warming). The study emphasizes the need to fully consider the combined effects of temperature and precipitation in assessing the impacts of future climate change on soil carbon pools, especially under extreme climate scenarios.

83. 题目: Optimizing Nitrogen Application in a Pennisetum hydridum – Sesbania cannabina Intercropping System to Enhance Soil Carbon Sequestration and Soil Health in Agricultural Landscapes
文章编号: N25120812
期刊: Land Degradation & Development
作者: Rakhwe Kama, Zicheng Yi, Farhan Nabi, Sekouna Diatta, Chongjian Ma, Huashou Li
更新时间: 2025-12-08
摘要: Land degradation is currently one of the major threats to global food security and ecosystem stability, often leading to diminished soil organic carbon (SOC) and reduced agricultural productivity. Restoring soil health through sustainable practices is, therefore, paramount, with a critical knowledge gap regarding the synergistic mechanisms between the high‐biomass grass Pennisetum hydridum and the nitrogen‐fixing legume Sesbania cannabina , and how nitrogen management optimizes their combined potential to enhance soil carbon sequestration. Soil carbon sequestration is critical for mitigating climate change and improving soil health in agricultural systems. While well‐studied in forests and grasslands, the interactive effects of planting patterns and nitrogen (N) fertilization on carbon dynamics in cultivated farmland require further exploration. This study investigates the influence of N application levels (0, 100, and 200 kg N ha −1 ) and cropping systems on SOC sequestration and its mechanisms. Through integrated pot and field experiments, changes in SOC components, including particulate organic carbon (POC), readily oxidizable organic carbon (ROC), and microbial biomass carbon (MBC) were assessed. Our findings revealed that cultivated soils significantly enhanced all measured carbon fractions compared to abandoned land, with an increase of 16.01% in soil organic matter, 12.94% in total nitrogen, 46.07% in POC, 31.78% in ROC, and 248.59% in MBC. Higher carbon storage capacity was noted under monocropped Pennisetum hydridum , whereas the leguminous Sesbania cannabina (MSc) contributed significantly to nitrogen fixation and labile carbon pools. The intercropping system (IPc‐Sc) synergized these benefits, boosting carbon sequestration by enhancing organic matter input and stabilizing soil structure more effectively than monocropping. Furthermore, N fertilization significantly altered soil enzyme activities, indicating a shift in microbial‐mediated carbon cycling. However, excessive N application (200 kg N ha −1 ) risked accelerating SOC decomposition. This study demonstrates that intercropping P. hydridum with S. cannabina under optimized N fertilization (100 kg N ha −1 ) effectively enhances soil carbon storage, boosts agroecosystem productivity, and promotes sustainable land management.

84. 题目: Biochar Lifecycle Contribution to Carbon Neutrality: Key Factors and Regulatory Mechanisms.
文章编号: N25120811
期刊: Environmental Science & Technology
作者: Aoxue Yu, Jiangfang Yu, Ya Pang, Jing Tang, Jiajia Wang, Nile Wu, Lin Tang
更新时间: 2025-12-08
摘要: Biochar, a carbon-enriched material derived from pyrolyzed biomass, has evolved from an ancient farming practice into a mature carbon sequestration technology, emerging as a pivotal strategy for achieving carbon neutrality. Nevertheless, heterogeneous production methodologies, multifactorial interactions, and diverse application scenarios pose significant challenges in establishing reliable assessment frameworks for practical implementation. From the perspective of biochar lifecycle and supplemented by data analysis, this critical review focuses on the key influencing factors of biochar applied in three main carbon-negative areas (including soil, construction, and carbon absorption), along with their influence mechanisms, challenges, and further prospects. In addition, the study evaluates machine learning applications in biochar research, highlighting their predictive optimization capabilities for tuning operational parameters and guiding precise application. These computational advances establish a paradigm shift toward precision-controlled biochar deployment in heterogeneous environmental systems.

85. 题目: Soil redox status and dissolved organic matter control the biogeochemical transformations of arsenic in paddy soils
文章编号: N25120810
期刊: Journal of Hazardous Materials
作者: Chuan Chen, Wanying Qu, Zi-Yu Gao, Zhenguo Tian, Si-Yu Zhang, Peng Wang, Fang-Jie Zhao
更新时间: 2025-12-08
摘要: Biogeochemical processes in paddy soils are strongly influenced by redox oscillations, but the linkage between redox status, abundance and transcription of microbial functional genes and their hosts, and biogeochemical transformations of arsenic (As) is not fully understood. We conducted incubation experiments with a constructed soil slope, which was partially submerged to generate a redox potential (Eh) gradient. As Eh decreased down the slope, the abundance of the genes representing iron (Fe) reducing bacteria (Geo), and encoding dissimilatory sulfite reductase (dsr), arsenate [As(V)] reductase (arrA and arsC) or arsenite [As(III)] methylation (arsM) increased, consequently enhancing the reductive mobilization of Fe and As, sulfate reduction, and microbial As methylation. Flooding increased the transcription of arrA and arsM by 14.9-fold and 4.5-fold, respectively. Draining followed by reflooding markedly decreased dissolved organic carbon (DOC) and hindered Eh decline, suppressing microbial functional genes and reductive processes of Fe and As, and of As methylation. Reflooding with a rice straw extract partially restored the abundance of microbial functional genes, reductive processes and As methylation, whereas removal of DOM by the addition of activated carbon (AC) produced opposite effects. Structural equation modeling revealed that porewater DOM directly affected Eh, subsequently impacting the abundance of functional genes and biogeochemical transformations of Fe and As. Responsive microbial hosts for transcribed arrA, arsC and arsM were identified. This study shows that porewater DOM and soil Eh critically control reductive mobilization of Fe and As biogeochemical transformations in paddy soil through impacting functional genes abundance, transcription and composition of microbial hosts.

86. 题目: Iron-modified crab shell biochar elicits synergistic plant and microbial responses for enhanced remediation of cadmium and arsenic co-contaminated soil
文章编号: N25120809
期刊: Journal of Environmental Chemical Engineering
作者: Caiya Yan, Xiaofang Ouyang, Yuhao Cai, Hua Yin
更新时间: 2025-12-08
摘要: The synergistic remediation of arsenic (As)-cadmium (Cd) co-contaminated farmland remains challenging due to their distinct geochemical behaviors. While current research primarily emphasizes short-term immobilization effects, knowledge gaps persist concerning the ecological interaction mechanisms and long-term stability of remediation materials during aging processes, which severely limit their large-scale application. Through a 180 day aging incubation followed by a 60 day pot experiment with iron-modified crab shell biochar (FBC) applied at 1%-3%, this study revealed interactions among plants, soil, and microorganisms. FBC simultaneously transformed Cd and As into reducible forms, reducing Cd bioavailability by 40.08%-55.94%. It also enhanced radish seedling growth, increasing root length and fresh weight by 37.01% and 93.68%, respectively, while reducing Cd and As accumulation in leaves by up to 92.29% and 71.54%. Notably, a 1% FBC application achieved effective remediation, highlighting its cost advantage. Plant growth enhanced soil nutrient cycling and facilitated the transformation of As from oxidizable to reducible forms. Microbial molecular network analysis revealed that FBC enriched metal-resistant genera such as Luteimonas and enhanced microbial network cooperation, with 97.42% of the interactions being positive. Multivariate statistical analyses (partial least squares path modeling, redundancy analysis, and Mantel test) demonstrated that FBC facilitated interactions among soil physicochemical properties, plant growth, and microbial communities. This study not only provides a waste-to-resource material but also elucidates the multidimensional ecological response patterns of FBC in remediating As and Cd co-contaminated soils, thereby establishing a theoretical foundation for its large-scale application and risk assessment.

87. 题目: Brown Carbon Optical Variability in U.S. Urban Aerosols Revealed by an Enhanced Spectral/Mass Balance Approach
文章编号: N25120808
期刊: Environmental Science & Technology Letters
作者: L.-W. Antony Chen, Judith C Chow, Xiaoliang Wang, Junji Cao, Jingqiu Mao, John G Watson
更新时间: 2025-12-08
摘要: Light absorption by brown carbon (BrC) represents a major uncertainty in assessing the climatic effects of carbonaceous aerosols. Using 38,622 PM_2.5 samples collected from the U.S. Chemical Speciation Network (2016–2018) and analyzed by a multiwavelength thermal/optical analyzer (TOA), we applied an enhanced spectral/mass balance receptor model to quantify black carbon (BC), BrC, and nonabsorbing white carbon (WtC) while allowing BrC optical properties to vary across samples. The model achieved excellent fits (r² > 0.98) and revealed a wide range of BrC absorption Ångström exponent (AAE_{405–635 nm} = 2.13 ± 0.74) and mass absorption efficiency (MAE_532 nm = 2.03 ± 0.35 m² g^–1). An inverse AAE–MAE relationship was found, with strongly to moderately absorbing BrC being the most prevalent BrC classes. Seasonal patterns showed higher “organic brownness” (i.e., higher BrC mass fraction in organic carbon regardless of BrC class) but lower MAE in winter and the opposite in summer, reflecting the bleaching evolution of BrC with photochemical aging. BrC abundance also influenced the reconciliation between BC- and TOA-derived elemental carbon, likely through altered thermal–optical carbon analysis splits. This study provides the first nationwide characterization of BrC optical variability from national network data, establishing a scalable framework toward long-term monitoring of organic aerosol absorption within existing regulatory programs.

88. 题目: Synergistic effects of composite amendment on carbon sequestration of stable carbon in farmland soil
文章编号: N25120807
期刊: Journal of Environmental Chemical Engineering
作者: Zitao Ma, Shujuan He, Xian Zhu, Yao Cui, Muqing Yang, Hengxu Zhou, Peiyi Zeng
更新时间: 2025-12-08
摘要: Soil is the largest terrestrial carbon pool and has significant sequestration potential. Existing research primarily uses soil organic carbon as the primary indicator for soil carbon sequestration. However, owing to its dynamic nature, it has not been incorporated into carbon sink accounting systems, making the search for a stable soil carbon sequestration accounting indicator urgent. Soil organic carbon is divided into active organic carbon and stable carbon, with the latter being stable over the long term and thus suitable as a key indicator of soil carbon sequestration. Mineral-associated organic matter (MAOM) and benzene polycarboxylic acids (BPCAs) are important components of stable soil carbon; however, their synergistic carbon sequestration effects under composite amendments are unclear. In this study, biochar, sepiolite, and their combinations were applied to a contaminated farmland. Sepiolite rapidly increased MAOM-C, whereas biochar enhanced the long-term accumulation of BPCAs. The composite treatment synergistically increased MAOM-C and BPCAs by 24.69% and 3038.71%, respectively, demonstrating superior sequestration (biochar + sepiolite > sepiolite > biochar). It also reduced the available Cd (-35.07%) and Pb (-31.07%), with significant negative correlations between stable carbon and heavy metal availability (p < 0.05), confirming a co-benefit effect. A carbon accounting model estimated the sequestration of 82013.86 kg CO₂eq ha^-1 after two years of cultivation. This study provides a MAOM- and BPCA-based accounting method that advances soil carbon sink strategies and promotes safe farmland use.

89. 题目: Aquaculture conversion triggers iron-driven organic carbon destabilization in Estuarine Wetlands
文章编号: N25120806
期刊: Plant and Soil
作者: Junpeng Li, Qingsong Zeng, Shuling Tang, Yingzi Wu, Yi Zheng, Weiqi Wang, Peipei Xue, Jordi Sardans, Josep Peñuelas
更新时间: 2025-12-08
摘要: Aims Estuarine wetlands are critical organic carbon sinks, where Fe oxides bind with organic carbon to form Fe-bound organic carbon (Fe-OC), which plays an important role in carbon sequestration within these ecosystems. The conversion of natural estuarine wetlands into aquaculture ponds leads to notable changes in both the Fe content and the Fe-OC pool. The goal was to reveal the interactions among these bacteria, soil iron, and Fe-OC throughout the transformation process. Methods We analyzed three typical Chinese estuarine wetlands to investigate changes in Fe fractions, Fe-OC and Fe-related bacterial communities (Fe-oxidizing bacteria and Fe-reducing bacteria) during aquaculture pond conversion, along with their interrelationships. Results After land-use change, Fe-OC and the molar OC:Fe rations (OC:Fe) in all soil layers decreased significantly by over 54% and 49%, respectively, while the Fe crystalline ratio (the ratio of crystalline Fe oxides to free Fe oxide) increased significantly by more than 100% across all layers. Among the Fe fractions, amorphous Fe oxides (Feo), complexed Fe oxides (Fep), and Fe-OC were key factors regulating Fe-reducing bacteria (p < 0.01). In turn, those Fe-related bacteria affected the Fe cycle and the transformation of Fe oxides (mainly Feo and Fep), thereby influencing Fe-OC and OC:Fe. Conclusions The transformation process leads to Fe reduction, Fep depletion, and Feo crystallization, resulting in the loss of Fe-OC. To safeguard the carbon storage function of estuarine wetlands, it is essential to minimize wetland exploitation and implement strategies to curb Fe oxide loss and crystallization, thereby enhancing the stability of these critical carbon pools.

90. 题目: Occurrence characteristics and ecological risks of fluorescent whitening agents in water bodies around a landfill
文章编号: N25120805
期刊: Journal of Hazardous Materials
作者: Xuejing Yang, Mengfei Su, Yifei Wang, Yu Guo, Bo Yao, Shuwen Yan, Yonghui Han, Jiansheng Cui
更新时间: 2025-12-08
摘要: The occurrence and ecological risks of fluorescent whitening agents (FWAs) in landfill leachate and surrounding water bodies were reported in this study. Both traditional and emerging FWAs were prevalent in the target samples, but at the ng L⁻¹ levels. The total FWA concentrations exhibited a gradual decreasing trend along the groundwater flow direction. Although the landfill is a potential source of ionic FWAs, it has effectively restricted the diffusion of these contaminants into surrounding aquatic environment. Our analysis revealed that the relative proportions of dissolved organic matter (DOM) components (C1, C2, C3) could serve as reliable indicators of the extent to which water bodies are impacted by the adjacent landfill. In other words, the greater the landfill's influence on the water body, the lower the percentage of C1 and the higher the percentages of C2 and C3 in the water's DOM, and vice versa. The ecological risk assessment revealed that all of the groundwater and surface water samples reached high-risk levels, with six ionic FWAs contributing more than 85% of the total RQsum values at most of the monitoring sites, and five of these ionic FWAs were identified as high toxicity priority contaminants. These findings underscore the need for greater attention to the environmental impacts of ionic FWAs, especially their significant effects on surface water, while also suggesting that agricultural plastic waste and residential laundry wastewater discharges may have a greater influence on surrounding water bodies than landfill leachate, warranting prioritized investigation.

91. 题目: Complementary mechanism of the Fenton and biological aerated filter in treating refractory dissolved organic matter from landfill leachate
文章编号: N25120804
期刊: Journal of Environmental Management
作者: Yonggan Li, Jiayi Li, Wenxia Wang, Zhenguo Chen, Yongxing Chen, Xiaojun Liang, Xiaojun Wang
更新时间: 2025-12-08
摘要: The Fenton and biological aerated filter (BAF) combined process have outstanding advantages in treating refractory and complex organic wastewater. However, the transformation of dissolved organic matter (DOM) in the actual wastewater treatment plant by Fenton and BAF, especially the complementary mechanism of the two processes in removing DOM at the molecular level, has rarely been reported. In this study, we evaluated the performance of a full-scale Fenton and BAF combined process for treating biochemical effluent (BE) from landfill leachate and analyzed the transformation of DOM and the complementary effects of the two processes at the molecular level using Fourier transform ion cyclotron resonance mass spectrometry. The removal efficiency of chemical oxygen demand in BE by the combined process can reach 96.78 %. The sulfur-containing refractory compounds were degraded into sulfur-free compounds by desulfonation after Fenton treatment. The Fenton can preferentially remove DOM components with high aromaticity (modified aromaticity index (AImod) = 0.257) and low O/C (intensity-weighted average value (wa) of the O/C = 0.358), producing macromolecular organic substances with low aromaticity (AImod = 0.234) and high O/C (O/Cwa = 0.524). The subsequent BAF process can complementarily remove the products of Fenton, thereby improving the overall treatment efficiency. Desulfonation (8.0 %) and oxygen addition (42.4 %) are the main paths leading to DOM transformation in the Fenton unit, while the BAF unit mainly removes Fenton products through decarboxylation (40.5 %). This study provides a more comprehensive understanding of the complementary role of the Fenton and BAF processes in effectively treating refractory organic wastewater.

92. 题目: Impact of anaerobic time on aerobic granular sludge performance: Insights from extracellular polymeric substances and microbial community perspectives
文章编号: N25120803
期刊: Journal of Environmental Management
作者: Yangzhi Yang, Yueqiao Wang, Hengwei Zhang, Gonglei Wang, Shuai Wang, Jixiang Yang, Jinsong Guo, Fang Fang
更新时间: 2025-12-08
摘要: Structural stability is a key challenge for aerobic granular sludge (AGS) technology. This study investigated the effects of anaerobic feeding time (40, 60, and 80 min) on AGS performance under an anaerobic-aerobic operational mode, and elucidated the underlying mechanisms from the perspectives of extracellular polymeric substances (EPS) characteristics and microbial community. The results demonstrated that AGS exhibited the highest stability when the anaerobic time was 60 min. Fourier-transform infrared and X-ray photoelectron spectroscopy results indicated that enhanced performance was attributed to EPS with strong hydrophobicity and gel-forming capacity due to elevated hydrogen bonding. A high abundance of EPS-secreting and slow-growing bacteria further supported sludge integrity. In addition, random forest and variance partitioning analyses identified EPS properties and microbial community as the primary factors of performance. This study revealed a potential mechanism by which anaerobic time regulates AGS stability through coordinated effects on EPS and microbial succession, offering valuable theoretical support for process optimization.

93. 题目: Combining cyanobacteria biocrust and biochar for immobilization of Cd in the collected soil surrounding tailing areas in semi-arid northwest China
文章编号: N25120802
期刊: Plant and Soil
作者: Zhe Wang, Ruihong Liu, Fenghui Sun, Weida Wang, Qinghong Jiang, Haili Shang, Chunli Zheng
更新时间: 2025-12-08
摘要: Background and aims Soil heavy metal pollution around tailings in arid and semi-arid regions may pose a greater threat to the ecological environment, especially caused by cadmium (Cd). It is urgent to develop in-situ passivation remediation technology. This research assessed the efficiency of the integration of biochar application and artificial cyanobacteria inoculation for the immobilization of Cd2+. Methods Through soil incubation experiments, the effects of cyanobacterial biocrust-biochar on soil physicochemical properties, the bioavailability and fractions of Cd2+, the fluorescence characteristics of extracellular polymeric substances (EPS), the microbial community composition and Cd resistance gene abundance were systematically analyzed. Results After 45 d of inoculation, cyanobacteria biocrust-biochar not only increased soil pH, cation exchange capacity (CEC), organic carbon (OC), available nitrogen (AN), EPS content and the abundance of Cd resistance-related genes, but also effectively reduced Cd2+ bioavailability and migration efficiency. The proportion of acid-soluble Cd in the soil decreased by 24.92%, whereas the residual Cd fraction increased by 42.68% compared to the control (CK). The combined application of the two amendments achieved the highest efficiency in immobilizing Cd2+. Cyanobacteria biocrust-biochar can immobilize Cd2+ in soil by regulating EPS secretion, promoting Cd-resistant gene expression, and improving soil physicochemical properties, thereby achieving synergistic Cd2+ stabilization. Conclusions These findings demonstrate that the combination of biochar amendment and cyanobacteria inoculation technology shows great potential as a passivation approach for remediating soil contaminated with Cd.

94. 题目: Rhizosphere affects the accrual of aggregate-associated soil organic carbon and its fractions across four dominant tree species in Northeast China
文章编号: N25120801
期刊: Plant and Soil
作者: Qianru Ji, Haitong Liu, Junrui Han, Xiangnan Fan, Wenjie Wang, Huimei Wang
更新时间: 2025-12-08
摘要: Background and Aims The rhizosphere plays a critical role in the formation and stabilization of soil aggregates, as well as soil organic carbon (SOC) dynamics. This study aimed to investigate how rhizosphere influences SOC and its fractions at the aggregate scale. Methods We collected rhizosphere soil samples across four dominant tree species (Fraxinus mandshurica, Larix gmelinii, Betula platyphylla, and Pinus sylvestris) in Northeast China. Results F. mandshurica had the highest SOC stocks, 1.67 times higher than L. gmelinii, which had the lowest SOC stocks. Across all tree species, rhizosphere soil generally contained higher SOC content than non-rhizosphere soil in most aggregate size classes, except for large macroaggregates. The SOC content varies with the aggregate size class. Microaggregates had the highest SOC content in the rhizosphere and non-rhizosphere soil. Both particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) were predominantly concentrated in microaggregates. The rhizosphere soil of F. mandshurica had the highest MAOC content (14.96 g/kg) among the four tree species and the lowest POC/MAOC ratio (0.77). Correlation analysis revealed a stronger relationship between SOC content in rhizosphere aggregates and rhizosphere SOC content than in non-rhizosphere. The POC/MAOC ratio in small macroaggregates was the strongest factor driving variations in aggregate-associated SOC and its fractions. Conclusion Rhizosphere obviously influenced SOC and its fractions at the aggregate level and enhanced SOC sequestration across all tree species.

95. 题目: MnO2 Structural Polymorph-Mediated Interaction with Dissolved Organic Matter: Underlying Protection and Transformation Mechanisms
文章编号: N25120609
期刊: Environmental Science & Technology
作者: Zhiqiang Wang, Zihan Shi, Tiantian Xu, Yaru Zhu, Haokai Zhao, Wanyi Xie, Bowen Qi, Chi Zhang, Kecheng Zhu, Hanzhong Jia
更新时间: 2025-12-06
摘要: MnO₂ plays an important role in protecting/transforming dissolved organic matter (DOM). However, the diversity of MnO₂ solid-phase speciation challenges the analysis of DOM–mineral interactions. Herein, the adsorption, protection, and transformation of DOM by MnO₂ polymorphs were investigated. Our findings showed that MnO₂ with a large specific surface area adsorbs more DOM; however, the protection of DOM is primarily related to the phase structure of MnO₂. Compared to the tunnel-structured α- and β-MnO₂, the physical entrapment within the layers provided by δ-MnO₂ is more conducive to maintaining the stability of DOM. Additionally, δ- and α-MnO₂ can generate a large amount of reactive oxygen species (ROS), such as hydrogen peroxide, hydroxyl radical, and superoxide, facilitating the transformation of DOM into low-molecular-weight (m/z 100–333) lignin or inorganic carbon. By contrast, β-MnO₂ exhibited negligible ROS production, instead oxidizing DOM through Mn⁴⁺ redox to generate midmolecular-weight (m/z 334–566) lignin, proteins, and lipids, and high-molecular-weight (m/z 567–800) lignin and lipids. Our results demonstrate that the MnO₂ crystal structure exerts a dominant regulatory influence on DOM protection, whereas the abundance of Mn⁴⁺ and ROS determines the transformation of DOM. These findings provide critical insights into the understanding of DOM fate in the environment.

96. 题目: Molecular-level determination of chloride-induced shifts in DOM transformation in UV/H2O2 and UV/PDS systems
文章编号: N25120608
期刊: Separation and Purification Technology
作者: Zhepei Gu, Feiyan Fang, Xiaoyu Wang, Qibin Li
更新时间: 2025-12-06
摘要: High chloride (Cl⁻) concentrations in wastewater complicate the transformation of dissolved organic matter (DOM) during advanced oxidation processes (AOPs). This study investigated the impact of Cl⁻ on the transformation of Suwannee River natural organic matter (SRNOM), a highly unsaturated and aromatic DOM certified reference material, in ultraviolet-activated hydrogen peroxide (UV/H₂O₂) and ultraviolet-activated peroxydisulfate (UV/PDS) systems. The inhibitory effect of Cl⁻ on DOM removal was more significant in the UV/PDS system; at 56.4 mM Cl⁻, total organic carbon removal decreased by 22.81 %. Ultrahigh-resolution mass spectrometry showed that Cl⁻ promoted the formation of highly oxygenated, highly unsaturated, and phenolic (HO-HUPh) compounds while suppressing their further degradation to aliphatic (Ali) species. This effect occurred in both systems but was stronger in the UV/PDS system because Cl⁻ shifted the dominant reactive species from SO₄^•− to reactive chlorine species (RCS, e.g., Cl₂^•−), whereas hydroxyl radicals remained dominant in the UV/H₂O₂ system. Reactive chlorine species enhanced oxygen addition to DOM but impeded decarboxylation and dealkylation, leading to the accumulation of HO-HUPh intermediates. The UV/PDS system also generated more potentially toxic chlorinated organic byproducts than the UV/H₂O₂ system (558 vs. 406 molecular formulas). These findings provide a basis for optimizing AOPs for chloride-rich wastewater.

97. 题目: The effect of microplastics on the adsorption of ofloxacin and Cu (II) by sawdust biochar
文章编号: N25120607
期刊: Separation and Purification Technology
作者: Zhen Li, Weinan Liu, Fanbin Meng, Xiaona Wu, Zhongfei Xu, Yiyi Wang, Lidong Wang
更新时间: 2025-12-06
摘要: Microplastics (MPs) as well as antibiotics and heavy metals are typical pollutants in the aquatic and soil environment. In this study, the effects of polystyrene (PS) or polyethylene terephthalate (PET) on adsorption behaviors and mechanisms of biochar (BC) for ofloxacin (OFL) and coexistent Cu(II) were investigated. The adsorption kinetics of OFL and Cu(II) reached equilibrium within 24 h, fitting the Elovich model. The adsorption quantities of OFL increased at low concentrations in the present of PS/PET but decreased at high concentrations due to site competition, while Cu(II) adsorption slightly increased. Aged PS/PET significantly enhanced adsorption by generating active sites. The influence of pH, humic acid and real water environment on the adsorption of OFL and Cu(II) were also studied. According to fourier transformation infrared spectrum and density functional theory, PS/PET act as both adsorbates and adsorbents in the system. The complex of BC/PS/PET-Cu(II)-OFL was formed. Benzene ring and CO on MPs were the main functional groups influencing the adsorption of OFL and Cu(II). Electrostatic interaction, hydrophobic interaction, hydrogen bonding, π–π interaction, pore filling and complexation were key mechanisms for adsorption. This study provides new perspectives on adsorption behaviors and interaction mechanisms between ternary pollutants.

98. 题目: Mechanistic insights into the sediment accumulation and fractionation of PAHs: Role of sedimentary organic carbon and an assessment of environmental implications
文章编号: N25120606
期刊: Water Research
作者: Weijie Liu, Xinli Xing, Xingchen Liu, Andrew J Sweetman, Gaigai He, Shibin Qin, Peng Li, Li Liu, Xiaoshui Li, Shihua Qi
更新时间: 2025-12-06
摘要: Increasing anthropogenic activities and carbon aging processes pose a significant global concern to understanding the accumulation mechanisms of polycyclic aromatic hydrocarbons (PAHs) in sediments, especially regarding the overlooked role of nonextractable residues (NERs). Herein, we investigated the accumulation patterns of three PAHs fractions (bioavailable-BPAHs, extractable -EPAHs, and NERs), hydrodynamic conditions, and organic matter sources of sediment across different types lakes. This study reveals a previously overlooked potential relationship among anthropogenic factors, hydrodynamic condition, sedimentary organic carbon (SOC) profiles, and PAH fractions based on the mantel’s test and structural equation model (SEM). A significant feature influencing the occurrence of EPAHs and NERs was attributed to SOC fractions, especially for sedimentary labile (LOC) and recalcitrant organic carbon (ROC) pools. LOC mainly controlled the EPAH distributions, while ROC may further accelerate the sedimentary accumulation of NERs. The quantitative structure activity relationship (QSAR) modelling further suggested that a strong positive relationship between hydrophobic PAH and the proportion of EPAHs was attributed to molecular reactivity and mobility based on high Egap, increased entropy, and van der Waals interactions. However, the formation of NERs was primarily driven by molecular polarity (μ, α) and electrophilic potential (qC⁺). The inclusion of BPAHs into PAH-based risk calculations and subsequent sediment management strategies is recommended, improving our understanding of the environment significance of the three PAHs fractions. Overall, this study provided a mechanistic insight into the fate of PAHs in sediment by carbon cycling processes and molecular-scale interactions.

99. 题目: Effects of nitrogen addition on SOC in alpine grasslands of the Qinghai-Tibetan Plateau and adjacent mountain regions: a meta-analysis
文章编号: N25120605
期刊: Frontiers in Environmental Science
作者: Yadong Yang, Tao Wang, Kangshun Wang, Sen Zhang, Lingzhi He, Qiangshun Wu
更新时间: 2025-12-06
摘要: AimsNitrogen (N) deposition has emerged as a major driver of ecological change in alpine grasslands of the Qinghai-Tibetan Plateau under global climate change. To predict the ecological consequences of increasing nitrogen deposition, nitrogen addition experiments have been widely employed as a key methodological approach to simulate this process. However, the effects of nitrogen addition—considering its rate, duration, and form—on carbon (C) dynamics in these ecosystems remain inconsistent across studies. Understanding these effects is critical for predicting global carbon stocks and guiding sustainable grassland management.MethodsWe conducted a meta-analysis of 57 peer-reviewed studies (794 observations) to quantify the response of alpine grassland C dynamics to N addition.ResultsN addition significantly increased plant-derived carbon inputs, increasing aboveground biomass by 42.7%, belowground biomass by 16.2%, and dissolved organic carbon (DOC) by 10.7%. The soil organic carbon (SOC) content increased by 3.6% overall. Conversely, soil respiration decreased by 5.1%, whereas the microbial respiration rate increased by 21.9%. The addition of nitrogen decreased the soil pH by 0.20 units and the soil C/N ratio by 1.7%. The soil ammonium (NH4+) and nitrate (NO3-) contents decreased by 20.1% and 52.1%, respectively. The microbial biomass nitrogen (MBN) increased by 14.5%, whereas the microbial biomass carbon (MBC) decreased by 2.8%. The soil fungal-to-bacterial ratio (F/B) decreased by 31.0%.ConclusionThese results indicate that shifts in microbial community structure drive SOC dynamics in alpine grasslands. Short-term N addition (≤5 years; ≤30 kg N ha-1 yr-1) enhances SOC through increased plant biomass and microbial C sequestration. However, long-term additions promote C loss via soil acidification and a critical shift in the microbial community, notably a decreased fungal-to-bacterial ratio. To sustain alpine ecosystem function, N addition rates should not exceed 10 kg N ha-1 yr-1. Future research should prioritize interactions between N deposition status and soil acidification/microbial function in high-altitude regions.

100. 题目: Enhancement of nitrobenzene degradation by co-pyrolysis biochars in sulfide-mediated aqueous environment:adsorption and reduction contribution
文章编号: N25120604
期刊: Environmental Research
作者: Yadong Yang, Tao Wang, Kangshun Wang, Sen Zhang, Lingzhi He, Qiangshun Wu
更新时间: 2025-12-06
摘要: In-situ reductive remediation is promising for groundwater treatment due to the natural abundance and stability of sulfides. This study developed co-pyrolysis biochars from wormwood (W) and lobster shells (L) to enhance sulfide-driven nitrobenzene (NB) reduction. The biochars were produced at varying W:L ratios (1:0, 3:1, 1:1, 1:3 and 0:1) and pyrolyzed under 700°C. The co-pyrolyzed W1L1 (W: L ratio = 1:1) significantly enhanced the reduction removal capacity of NB compared to biochar from single biomass, achieving 99.2% NB removal (sulfide: 2 mM, pH: 9) with the pseudo-first-order kinetic constant (k_obs= 0.021 h^-1) for the reduction reaction stage. The enhancement mechanism involves: (i) NB pre-adsorption via microporosity and π–π interactions, (ii) The synergistic contributions—wormwood provided adsorption sites, while lobster shells introduced graphitic nitrogen (facilitating electron transfer) and oxygen-containing groups (promoting sulfide activation). (iii) The enhancement in electron transfer ability due to the high electrochemical surface area (0.123 cm²) and low charge transfer resistance (R_ct = 150.8 Ω). Furthermore, the applicability of co-pyrolysis biochar in NB removal was demonstrated across varied reaction conditions and groundwater environmental factors. The reduction pathway of NB proceeded via a three-step, two-electron transfer process, ultimately yielding aniline, with nitrosobenzene detected as an intermediate. These findings establish co-pyrolysis biochars as sustainable materials for in-situ NB remediation.