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101. 题目: Spectroscopic insights into the mechanisms driving spatial heterogeneity of dissolved organic matter in complex slope systems with patchy habitats in arid and semiarid regions
文章编号: N26090317
期刊: Geoderma
作者: Jun-jie Zhang, Hao Wang, Yu-yan Yang, Qing-wei Zhang, Qiang Zhang, Jian Wang, Ming Li
更新时间: 2026-09-03
摘要: Soil erosion profoundly influences dissolved organic matter (DOM) dynamics and regional carbon cycling in arid and semiarid regions. Complex slope systems, consisting of ridge slopes and gully slopes with abrupt topography and patchy habitats, may regulate DOM spatial distribution, yet the underlying mechanisms remain unclear. This study examined the spatial heterogeneity and drivers of soil DOM in a typical complex slope system by optical techniques. Overall, DOM composition varied with landscape position. Stable and humified DOM dominated at summit and gully shoulder line, while less-decomposed DOM accumulated at middle ridge slope and gully slope, the active erosion zones. Among habitats (i.e., Bothriochloa ischaemum (L.) Keng + biological soil crusts (BSCs) (BIBSCs), Artemisia sacrorum Ledeb + BSCs (ASBSCs), and BSCs), BSCs showed the highest dissolved organic carbon (DOC) content, while BIBSCs contained the largest fraction of humic-like DOM. DOC was highest in the top soil horizon across all three habitats. The top soil horizon contained higher proportions of humic-like and plant-derived DOM, whereas the bottom soil horizon was enriched in protein-like and microbial-derived DOM. DOM molecular weight, aromaticity, and humification degree declined with soil depth. The spatial heterogeneity of DOM was primarily controlled by habitat type, landscape position, and soil depth, which together influenced litter input, root density, and BSCs traits. These findings elucidate the coupling between topography, habitat, and DOM dynamics, providing evidence for improving regional carbon cycle models in arid and semiarid landscapes.

102. 题目: Application of biochar in bioelectrochemical systems: performance enhancement mechanisms and application of artificial intelligence in system optimization
文章编号: N26090316
期刊: Journal of Environmental Chemical Engineering
作者: Shilong Li, Yue Shi, Xin Ning, Qiusheng Gao, Dongmin Yang, Liang Duan
更新时间: 2026-09-03
摘要: In the context of the increasing global demand for wastewater treatment, traditional processes are characterized by high energy consumption and low efficiency, and are difficult to achieve resource recovery. The bioelectrochemical system (BES) has emerged as one of the most promising technologies, and the efficiency of electron transfer is the core factor limiting its performance. Biochar possesses a high specific surface area, rich pore structure, and good electrical conductivity. It can be used as an efficient electron mediator and functional carrier to enhance the performance of BESs. This review elaborates on the four core mechanisms by which biochar enhances the performance of BESs, including pollutant adsorption and enrichment, reaction environment regulation, electron transfer enhancement, and pollutant synergistic degradation. Additionally, the specific content of big data integration is thoroughly discussed, and the application paths of artificial intelligence (AI) in biochar and BESs coupling systems are deeply explored. Finally, the practical challenges of the BES-biochar system in terms of cost control, secondary pollution, recycling and regeneration, data barriers, and model interpretability are analyzed, and targeted solutions are further proposed. This review aims to clarify the microscopic mechanism of biochar enhancing BESs, explore the AI and big data-driven coupling path for BES-biochar, and promote the large-scale implementation of biochar and BES technology.

103. 题目: Diagnosing global soil organic carbon mapping discrepancies with interpretable machine learning: A comparison of soil type linkage and digital soil mapping
文章编号: N26090315
期刊: Geoderma
作者: Gaosong Shi, Zeyu Song, Wenye Sun, Zhongwang Wei, Yanqi Liu, Naikang Xu, Jingyi Wang, Anne Gobin, Qingliang Li, Wei Shangguan, Yongjiu Dai
更新时间: 2026-09-03
摘要: Soil property maps are essential for characterizing soil spatial heterogeneity and are critical for supporting land surface modelling, agricultural management, and climate change research. However, substantial discrepancies among existing global soil property datasets often result from differences in mapping approaches, particularly between the conventional soil type-linkage (STL) approach and modern digital soil mapping (DSM). In this study, we use an interpretable machine-learning framework that integrates extreme gradient boosting, Shapley additive explanations, and partial dependence plots to investigate the consistency and environmental sensitivity of soil organic carbon content (SOC) predictions with environmental factors. We compare two representative global maps: the Global Soil Dataset for Earth System Modeling (GSDE), based on STL, and SoilGrids 2.0 (SG), generated using the DSM framework. The primary analysis focused on topsoil SOC (0–5 cm), with an additional 30–60 cm analysis used to examine whether the main tendencies persisted at a deeper interval in Southwest China. We assessed spatial differences between datasets and used legacy soil profile observations as a reference for evaluating broad product–profile agreement and SOC–environment consistency. The results indicate that while both datasets captured the general pattern of higher SOC in mountainous regions and lower SOC in the Sichuan Basin, their predictions diverged substantially in humid, high-elevation areas and across sharp topographic transitions. The profile-referenced comparison suggested that SoilGrids showed relatively stronger agreement with the legacy profile observations in both mean and variability, whereas GSDE tended to show lower central tendencies and reduced variance. Interpretability analyses identified temperature and precipitation as important predictors in the surrogate models, with clear threshold responses, and highlighted important interaction effects among climatic and topographic factors. These findings help diagnose potential contributors to disagreement between DSM- and STL-based gridded products and provide guidance for cautious dataset interpretation and regional-scale diagnostic assessment. Importantly, this interpretable machine-learning framework provides a process-oriented diagnostic perspective on how environmental controls and their interactions are differentially represented across global soil datasets.

104. 题目: Divergent associations of 18O‑based and stoichiometric CUE with soil organic carbon along elevational gradients
文章编号: N26090314
期刊: Geoderma
作者: Zihao Fan, Jizhen Chen, Xin Zhang, Yuxing Ou, Jiaze Li, Zhilin Huang
更新时间: 2026-09-03
摘要: Microbial carbon use efficiency (CUE) is a key parameter linking microbial core processes to soil organic carbon (SOC) storage. Although the 18O labeling method and the ecoenzymatic stoichiometry model have been widely used to estimate CUE, how CUE derived from these two methods varies along elevation gradients and its relationship with SOC remain poorly understood. In this study, we applied both methods to a local elevational transect in Shennongjia (800–2900 m) and a multi‑site synthesis encompassing 16 mountain ecosystems across Asia. At the multi‑site scale, 18O‑CUE increased with elevation but showed a non‑significant positive trend with SOC. Locally, 18O‑CUE exhibited a unimodal pattern peaking at mid‑elevations, and its relationship with SOC became significantly negative after accounting for climatic covariation. By contrast, CUEC: N showed no consistent elevational trend at either scale but was negatively associated with SOC in the multi‑site synthesis, with a directionally consistent trend locally. At the local scale, microbial community attributes (e.g., fungal Shannon diversity, F:B ratio) predominantly determined 18O‑CUE, whereas at the multi‑site scale, soil pH was the dominant factor. For CUEC: N, MAT was the predominant driver at the local scale, and at the multi‑site scale, soil pH indirectly regulated CUEC: N through its effect on EEAC: N. These findings demonstrate that the ecological meaning of CUE is method‑dependent, highlighting the importance of distinguishing the two metrics when predicting microbial‑mediated carbon sequestration and its feedbacks to global change.

105. 题目: Fe–Mn modified sludge-derived biochar for peroxymonosulfate activation toward efficient Acid Orange 7 degradation: Insights into performance and mechanism
文章编号: N26090313
期刊: Separation and Purification Technology
作者: Tao Hou, Bo Wang, Hong-Li Lu, Mei-Qi Ren, Shuai Wang, Dan Cui, Yong-Zhen Peng
更新时间: 2026-09-03
摘要: Addressing the dual challenges of recalcitrant azo dye contamination in wastewater and sewage sludge disposal, this study developed a sustainable waste-to-resource strategy based on Fe–Mn-modified sludge-derived biochar (FM-SBC). The catalyst was synthesized via a one-pot impregnation–pyrolysis method and employed as an efficient activator of peroxymonosulfate (PMS) for the degradation of Acid Orange 7 (AO7). The optimized FM-SBC, containing 13.3 wt% Fe and 0.5 wt% Mn, exhibited outstanding catalytic performance, achieving 99.6 ± 0.2% AO7 removal within 20 min (kobs = 0.208 ± 0.001 min−1) and a normalized removal rate of 9.6 ± 2.0 mg g−1 min−1. This performance significantly surpassed that of pristine SBC (73.2 ± 2.8% removal, kobs = 0.035 ± 0.003 min−1). Mechanistic investigations using XPS and quenching analyses revealed that Mn(III) promoted the reduction of Fe(III) to Fe(II), establishing a synergistic Fe/Mn redox cycle. Coupled with electron transfer from sp2-hybridized carbon domains, this synergy facilitated PMS activation via a 1O2-dominated non-radical pathway. Degradation intermediate analysis combined with ECOSAR prediction, indicated that all identified transformation products exhibited lower acute, chronic, developmental, and mutagenic toxicity than the parent AO7. Moreover, FM-SBC showed good reusability, retaining over 87.3% of its initial removal efficiency after six consecutive cycles, with low leaching rates of Fe (15.6%) and Mn (5.7%). Overall, this work demonstrates a cost-effective and environmentally sustainable approach for simultaneous sewage sludge valorization and efficient azo dye removal, highlighting the practical potential of Fe–Mn-modified sludge-derived biochar as a PMS-based catalyst for wastewater treatment.

106. 题目: FeSO4 combined with intermittent aeration promotes humification during rapeseed straw composting by sustaining Fe-ROS activity
文章编号: N26090312
期刊: Chemical Engineering Journal
作者: Yang Xu, Ting-Ting Wang, Zhao-Yong Sun, Yuxin Xiao, Min Gou, Yue-Qin Tang
更新时间: 2026-09-03
摘要: The recalcitrance of lignocellulosic structures in crop straw constrains compost humification. Reactive oxygen species (ROS) can oxidatively deconstruct lignocellulose and release humification precursors, whereas iron redox cycling may sustain ROS generation. Here, rapeseed straw composting was conducted under three treatments: continuous aeration without FeSO4 addition (CK), continuous aeration with FeSO4 addition (T1), and intermittent aeration with FeSO4 addition (T2). The effects on compost maturation, Fe-ROS dynamics, lignocellulose degradation, humification, and microbial succession were evaluated. Self-organizing map (SOM) analysis showed that T2 reached comparable maturity at 18 d, whereas CK and T1 reached this level at 35 d and 25 d, respectively. During the mid-to-late stages, T2 maintained higher Fe(II) levels and ROS activity, with H2O2 and •OH levels exceeding CK by 20.69–107.63% and 22.57–65.56%, respectively, and T1 by 7.97–33.80% and 13.38–58.14%, respectively, accompanied by enhanced lignocellulose degradation. Compared with CK, the Fmax values of humic-like C1 and humic-acid-like C4 in T2 increased by 16.19% and 35.57%, respectively. FT-ICR MS showed that T2 promoted DOM transformation toward higher unsaturation and aromaticity, with DBEw and AImodw reaching 7.57 and 0.19, respectively, accompanied by lignin-like and tannin-like humification products. In T2, intermittent aeration established a cyclic redox environment, sustaining Fe(II)/Fe(III) cycling via Fe(II)-mediated ROS generation under aerobic conditions and microbial Fe(III) reduction under oxygen-limited conditions. This cyclic environment further maintained ROS activity, enriching lignocellulose-degrading taxa (Thermobifida) and potential Fe-cycling taxa (Lysinibacillus and Geobacillus). Ultimately, the sustained ROS activity and the microbial activity accelerated lignocellulose deconstruction and promoted humification.

107. 题目: Agricultural Phosphorus Pollution Leads to a Two-Stage Release of Organic Matter in Sediments at the Bottom of Lake
文章编号: N26090311
期刊: Water Research
作者: Hankun Yang, Yun Xiao, Xingshe Zhu, Nigel J D Graham, Wenzheng Yu
更新时间: 2026-09-03
摘要: Agricultural non-point source phosphorus (P) pollution—primarily from phosphate fertilizers—significantly contributes to surface water P loading. Unlike existing findings that link P input to water eutrophication, this study identifies an additional critical pathway through which P threatens drinking water safety. The results of simulation experiments, described herein, showed that the phosphate entering surface water can lead to a two-stage, large-scale release of organic matter in the sediments. Phosphate rapidly displaces the organic matter in the upper layer of the sediments in the first stage, converting it into dissolved organic matter (DOM). Subsequently, phosphate can significantly alter the composition and function of the microbial community in the sediments during the second stage, thereby enhancing the decomposition of organic matter by microorganisms and causing a large release of organic matter from the sediment. Among them, the total organic carbon (TOC) of the supernatant increased by 1.5 ∼ 2 times, while that of the pore water decreased by 3.2 ∼ 4.3 times. Under the combined effects of chemical and microbial processes, the DOM concentration, aromaticity, average molecular weight, and humification degree in sediment-water systems all increased with rising initial P concentration and extended system operation time. In the context of drinking water supplies, these changes in surface water DOM led to an increase in the potential for the formation of disinfection by-products (DBPs) and the efficiency of DOM conversion into DBPs. After the addition of phosphate, the contents of trichloromethanes (THMs) and hydrofluoroacetic acids (HAAs) increased by 65% and 104% respectively. This study demonstrates that agricultural phosphate fertilizer pollution not only causes eutrophication but also leads to a decrease in water quality by releasing sediments organic matter. This process elevates DBPs formation risk, posing a threat to drinking water safety.

108. 题目: Recurrent climate dynamics and controls on organic matter during the late Pliensbachian and early Toarcian Jenkyns Event: Integrated palynological, geochemical, and mineralogical evidence from the Qiangtang Basin (eastern Tethys)
文章编号: N26090310
期刊: Palaeogeography, Palaeoclimatology, Palaeoecology
作者: Changjun Ji, Yinglie Li, Yan Wu, Zhenhan Wu, Yun Chen, Ning Yang
更新时间: 2026-09-03
摘要: The late Early Jurassic represents a critical interval in Earth history, characterized by global environmental and climatic instabilities that influenced paleoceanographic conditions and drove critical changes in faunal and floral communities. The most pronounced climatic shifts took place across the Pliensbachian/Toarcian (P/T) boundary, culminating during the early Toarcian Jenkyns Event. Both events correspond to severe shifts from icehouse to warm greenhouse climate states. In this study, an integrated multi-proxy approach of palynological, organic and inorganic geochemical, and mineralogical datasets from the Pliensbachian-Toarcian Qixiangcuo section, deposited under shallow marine shelf environments within the Southern Qiangtang Basin (Tibet), is employed to interpret paleoclimatic evolution and its control on organic matter accumulation. The late Pliensbachian–earliest Toarcian is marked by carbonate-dominated mineralogical composition and consistently low C-values, Ga/Rb, and elevated K2O/Al2O3, suggesting weak continental weathering and terrigenous input under arid to semi-arid climates. Palynofloral assemblages are dominated by xerophytic and megathermic conifer pollen, mainly of Cheirolepidiaceae and Pinaceae, with subordinate mesophytic components. This assemblage reflects a moisture-limited tropical climate driven by seasonal fluctuations in trade wind–monsoonal circulation. Across the Jenkyns Event, moderate chemical index of alteration (CIA) values, coincident with fluctuating trends in C-values, Sr/Cu, Rb/Al, and variations in clay minerals, quartz, and calcite contents, indicate alternating warm semi-arid to semi-humid climatic conditions along with modest continental weathering intensity, siliciclastic input, and oscillating hydrological conditions. This interpretation is further supported by palynofloral data, which displayed continued dominance of xerophytic conifers, punctuated by a short-lived contribution of mesophytic taxa and rare hygrophytic components, indicating episodic increases in precipitation and runoff. During the main stage of the Jenkyns Event, a temporary disappearance of dinoflagellate cysts (dinocysts) reveals a pronounced ecological stress corresponding to the dinocyst blackout event, likely driven by global warming and elevated seawater temperatures. Despite regional associations of organic carbon-rich sediments to the Jenkyns Event under enhanced anoxia, characterizing the Toarcian-Oceanic Anoxic Event (T-OAE), consistently low TOC contents at Qixiangcuo reflected limited organic matter production and burial due to semi-arid conditions and limited terrestrial organic matter supply, leading to limited primary productivity, well-established oxic conditions, and organic matter dilution. Regional to global comparisons with coeval strata in Europe and the eastern Tethys reveal significant spatial heterogeneity in paleoclimate evolution, attributed to paleogeographic position, atmospheric circulation, and latitudinal position within climatic belts. This study highlights the highly dynamic climatic evolution and regional contrasts across the Pliensbachian–Toarcian successions, which influenced sedimentation and controlled organic matter distribution.

109. 题目: Lithology and vegetation type heterogeneity influence soil organic carbon accumulation in Southwest China alpine karst
文章编号: N26090309
期刊: Journal of Soils and Sediments
作者: Haitao Li, Yonglin Wu, Chaoxiang Zhang, Xinran Liang, Xiaoyi Li, Zhihao Si, Fangdong Zhan, Yongmei He, Siteng He
更新时间: 2026-09-03
摘要: Purpose The unique lithology and vegetation types of karst ecosystems significantly affect the accumulation of soil organic carbon (SOC). However, the pathways by which lithology and vegetation influence SOC accumulation in high-altitude karst regions remain poorly understood. Methods We investigated two lithologies (limestone and dolomite) in the alpine karst region of southwest China, analyzing SOC composition and accumulation across a vegetation succession from grassland to shrubland, tree forest, and primary forest. Results The results show that lithology and vegetation significantly influenced soil properties and carbon-cycling enzyme activities. Dolomite soils had higher pH, total nitrogen (TN), total potassium (TK), and cellulase activity, while limestone soils exhibited higher total phosphorus (TP) and available phosphorus (AP). Primary forest showed the highest TP, AP, SOC, and mineral-associated organic carbon (MAOC) contents, with MAOC increasing along the succession gradient. Pyrolysis revealed aliphatics as the dominant soil organic matter (SOM) component in both lithologies. Random forest modeling indicated lignin and aliphatics as the primary predictors of SOC in limestone and dolomite, respectively. Correlation and hierarchical partitioning analyses indicated that β-glucosidase activity (31.04%) and dissolved organic carbon (DOC, 18.34%) were the primary factors explaining variation in SOC accumulation. Partial least squares path modeling (PLS-PM) showed vegetation primarily influences SOC via soil properties (path coefficient = 0.83), while lithology acts through SOM molecular composition (path coefficient = 0.39). Conclusion This study clarifies the distinct pathways through which lithology and vegetation influence SOC accumulation in alpine karst ecosystems, offering insights for carbon cycling understanding and sequestration strategies in fragile high-altitude regions.

110. 题目: Nature-based Solutions for the Remediation of Sulfentrazone-contaminated Soils: Integrating Macaúba Biochar, Microbial Inoculation, and Canavalia ensiformis
文章编号: N26090308
期刊: Water, Air, & Soil Pollution
作者: Tayna Sousa Duque, Fábio Ribeiro Pires, Caíque Menezes de Abreu, Iasmim Marcella Souza, Anderson Barbosa Evaristo, Simone Palma Favaro, José Barbosa dos Santos
更新时间: 2026-09-03
摘要: Persistent herbicide contamination of soils represents a challenge for sustainable agricultural systems, necessitating efficient remediation strategies. This study evaluated the effectiveness of Canavalia ensiformis associated with macaúba (Acrocomia aculeata) biochar and microbial inoculation for the phytoremediation of the herbicide sulfentrazone. The experiment was conducted under field conditions using a randomized complete block design (RCBD) with a 3 × 3 × 2 factorial arrangement, consisting of three sulfentrazone doses (0, 375, and 625 g a.i. ha⁻1), three remediation strategies (control, biochar, and biochar combined with microbial inoculation), and the presence or absence of C. ensiformis, with four replicates. Gas exchange, chlorophyll fluorescence, photosynthetic pigments, biomass production, and sulfentrazone residues in the soil were evaluated. Herbicide exposure reduced anthocyanin content by up to 44.6% and negatively affected photosynthetic and photochemical parameters at 40 days after sowing. However, physiological recovery was observed at 60 days, demonstrating the tolerance of C. ensiformis to the contaminant. The presence of the species reduced sulfentrazone residues by 74.56%, 80.14%, and 52.38% in the control, biochar, and biochar combined with microbial inoculation treatments, respectively. Considering herbicide doses, residue reductions reached 66.56% and 76.19% at 375 and 625 g a.i. ha⁻1, respectively. These results demonstrate that integrating plants, biochar, and microbial inoculation represents a promising strategy for the sustainable remediation of sulfentrazone-contaminated soils while promoting the valorization of residues from the macaúba production chain within a circular bioeconomy framework.

111. 题目: Fe/Mn Oxide-modified Rice Straw Biochar for Cd Immobilization in Farmland Soil: Performance, Redox Potential Response, and Mechanism
文章编号: N26090307
期刊: Water, Air, & Soil Pollution
作者: Zhigen Li, Zhixin Liu, Chia Chay Tay, Fan Huang, Yuanzhao Cao, Baowei Hu
更新时间: 2026-09-03
摘要: The issue of soil pollution in agricultural lands is intensifying, posing a significant threat to China’s agricultural output. Cadmium (Cd) pollution is a dominant problem as it can be easily taken by humans through food chains, which has had adverse effects on human health. In this study, the effects of biochar loading with Fe and Mn were examined on Cd immobilization from contaminated farmland soil. The Fe/Mn modified biochar (Fe/Mn@BC) was characterized and the results showed that modification enhanced the adsorption capacity of Fe/Mn@BC owing to more oxygen-containing groups and metal oxides crystals. After a 30d incubation experiment, the dissolved organic matter as well as pH, electrical conductivity, and cation exchange capacity increased under 5% Fe/Mn@BC. During 60d incubation experiment, the soil redox potential decreased to about -200 mv at the reduction phase and recovered to 482 and 197 mv for control and Fe/Mn@BC at oxidation phase respectively. Additionally, the application of Fe/Mn@BC immobilized more Cd as residual fraction during the last 20d oxidation period, which was consistent with the redox potential fluctuation. These results may provide evidence for the effectiveness of metal-modified biochar in remediating Cd in farmland soil.

112. 题目: H₂O₂-modified tyre biochar for phosphorus adsorption and fertiliser application
文章编号: N26090306
期刊: Plant and Soil
作者: Hend A Mohamed, Zed Rengel, Kadambot H M Siddique, Zakaria M Solaiman
更新时间: 2026-09-03
摘要: Background and aims Phosphorus (P) is an essential nutrient for global food production, and its depletion poses a major threat to agricultural sustainability. Concurrently, improper disposal of end-of-life tyres causes serious environmental risks. Converting waste tyres into functional biochar for P recovery offers a promising route to addressing both challenges by closing nutrient loops and valorising a problematic waste stream. This study investigated the potential of hydrogen peroxide (H₂O₂)-modified tyre-derived biochar (MTB) to enhance P adsorption from simulated P-rich wastewater and to enable its subsequent reuse as a slow-release fertiliser. Methods Untreated tyre biochar (PTB) was produced by pyrolysis and then oxidised with 10% H₂O₂ (1:10 w/w) at room temperature for 48 h to produce MTB. The P adsorption performance of PTB and MTB was tested at varying pH using batch experiments, with adsorption isotherms and kinetic models used to elucidate the removal mechanisms. A pot experiment with maize ( Zea mays L.) grown in nutrient‑poor soil amended with P‑loaded PTB vs P‑loaded MTB was conducted to evaluate fertiliser value. Results H₂O₂ modification significantly improved the biochar's surface properties, leading to higher P adsorption via chemisorption and electrostatic interactions. MTB achieved 99% P removal efficiency from the solution, compared to 20% for PTB. When applied to nutrient-poor soil, P‑loaded MTB increased maize shoot and root biomass by nearly threefold relative to P‑loaded PTB and unamended control, indicating enhanced P availability and nutrient use efficiency. Conclusion This study demonstrates that the H₂O₂-treated tyre biochar can effectively recover P from wastewater and act as a slow-release fertiliser, promoting plant growth and soil fertility to achieve both environmental and agronomic benefits. This dual application supports the development of circular waste management systems and sustainable agriculture.

113. 题目: Structure-informed prediction of organic matter thermodynamics from quantum chemistry and machine learning
文章编号: N26090305
期刊: Geochimica et Cosmochimica Acta
作者: Thomas P Sibille, Klaus-Holger Knorr, Oliver J Lechtenfeld, Maximilian P Lau
更新时间: 2026-09-03
摘要: Thermodynamic constraints shape the degradation and persistence of dissolved organic matter (DOM) in aquatic environments. Predicting the Gibbs energy of the oxidation half reaction per mole of carbon (ΔG°(Cox)) is therefore central to assessing the thermodynamic potential of organic matter degradation. A widely used approach is the linear relationship between nominal oxidation state of carbon (NOSC) and ΔG°(Cox), introduced by LaRowe and Van Cappellen, which provides a convenient and versatile single-proxy estimate. However, NOSC is a stoichiometric descriptor and assigns identical ΔG°(Cox) values to formulae that reflect structures differing by more than 90 kJ molC-1. This underlying diversity of structures can be isomeric, but can also reflect variation in molecular size, heteroatom composition, hydrogen abundance, and level of unsaturation. Here we present a structure-informed Random Forest model for ΔG°(Cox) trained on a curated set of over 3,500 quantum-chemically calculated DOM-relevant molecules spanning diverse elemental compositions and structures. The model was trained using formula-derived descriptors, including elemental ratios, molecular mass (Mr), double bond equivalence (DBE), heteroatom content, NOSC and others. Predictions are made at the molecular level and represent an average across potential isomers of a formula. It relies on ΔG°(Cox) data derived with the Becke three-parameter Lee-Yang-Parr density functional (B3LYP) and captures thermodynamic variability that the NOSC-based linear relationship systematically misses. As proof of concept, the model was applied to ultra-high resolution mass spectrometry (UHR-MS) data for four benchmark DOM reference materials, yielding ΔG°(Cox) distributions that are broader and multimodal compared to the NOSC-based estimates. These results demonstrate that machine learning models grounded in quantum chemical data provide a more differentiated thermodynamic representation of DOM formula space and support improved prediction of organic matter oxidation potential.

114. 题目: Co-evolution rhizosphere-microbe-mineral interfaces govern soil organic carbon stabilization and fertility
文章编号: N26090304
期刊: Applied Soil Ecology
作者: Sudhir Kumar Upadhyay, Antra Andotra, Prasann Kumar, Padmanabh Dwivedi, Devendra Jain
更新时间: 2026-09-03
摘要: The soil organic carbon (SOC) is the basis of climate regulation and soil fertility, and mineral-associated organic carbon (MAOC) is the most persistent fraction of it. Nevertheless, the rhizosphere processes underlying the development of MAOC are not well understood. Existing conceptualizations presuppose the disconnection of plant, microbial, and mineral processes, thereby restricting the predictive capabilities of dynamic environments. This review presents an integrative framework that conceptualizes root exudate-microbe-mineral interactions as co-evolving interfaces controlling SOC stabilization. Root exudates, which are made of various low and high-molecular-weight compounds, simultaneously control microbial metabolism and mineral surface reactivity through ligand exchange, dissolution-precipitation, and redox processes. These inputs are chemically assimilated by microbial processes, leading to the formation of biomass, extracellular polymeric substances, and necromass, which are important precursors of MAOC since they are enriched in reactive functional groups. The effectiveness of such transformations, which are governed by microbes' carbon-use efficiency and functional characteristics, determines whether carbon is stabilized or lost through respiration. Mineral surfaces also control the fate of carbon by adsorbing, bridging via cations, and co-precipitating carbon. In addition to exerting limitations, such as finite sorption capacity, and competitive binding. We emphasize mechanisms that have not been explored previously, such as transient organo-mineral interactions, competitive sorption, and mineral saturation thresholds. The rhizosphere is a dual-function zone where processes of stabilization and destabilization co-exist and therefore require integrated, process-based models to predict SOC dynamics.

115. 题目: Floc-mediated ozone microbubble enrichment enables reactive separation of dissolved organic matter
文章编号: N26090303
期刊: Journal of Environmental Chemical Engineering
作者: Yao Li, Jiyang Yao, Ming Tian, Xuan Wu, Pengkang Jin
更新时间: 2026-09-03
摘要: Ozone microbubbles (OMBs) have been reported to enhance ozone transfer and flotation separation, but their role after incorporation into coagulant-induced flocs remains insufficiently understood. This study investigated the interaction between OMBs and Al-organic flocs during hybrid ozonation-coagulation and its effect on dissolved organic matter (DOM) removal. Humic acid (HA) was used as a model DOM compound, and natural surface water was used for evaluation. During floc formation, OMBs were captured by Al-organic flocs, producing bubble-bearing ozone microbubble flocs (OMBF). Compared with freely dispersed OMBs, OMBF altered ozone accumulation/decay behavior and elevated redox conditions in the floc-associated region. Radical-probe and apparent hydroxyl-radical analyses further indicated stronger radical-related oxidation in OMBF, especially under weakly alkaline conditions. OMBF formation coupled HA oxidation with Al-mediated capture. Ozone-induced functionalization generated or exposed oxygen-containing groups, while hydrolyzed Al species incorporated part of the transformed HA-derived organics into the floc matrix. The dominant removal pathway was pH-dependent. At pH 6-7, Al-mediated complexation, bridging and floc growth were more favorable, whereas at pH 8 stronger radical-related oxidation promoted HA functionalization and urea-sensitive weak-interaction retention. OMBF retained 2.1-2.2 times higher secondary DOC capture capacity than air microbubble flocs and removed 65.0% DOC from natural surface water. These findings show that the integrated OMBF system improves DOM removal through the coupling of floc-associated ozone reactions, Al-mediated incorporation and subsequent separation.

116. 题目: Organic matter and greenhouse gas dynamics across contrasting hydrological states in intermittent rivers
文章编号: N26090302
期刊: Water Research
作者: Pan Huo, Tianyi Han, Jiayi Hou, Tianyi Zhang, Pengcheng Gao, Jinbo Li
更新时间: 2026-09-03
摘要: As intermittent rivers expand globally, understanding how contrasting hydrological conditions relate to organic matter (OM) characteristics and greenhouse gas (GHG) dynamics is important. We investigated CO₂ and N₂O dynamics across contrasting low-flow (LF) and high-flow (HF) campaigns in intermittent rivers. Pore-water GHG concentrations consistently exceeded those in overlying water, suggesting an important internal GHG pool. During the LF campaign, higher chlorophyll-a concentrations coincided with lower overlying-water CO₂ concentrations, whereas the HF campaign showed greater soil-OM contribution, higher DOC, a stronger humic-like/aromatic DOM signature, and higher dissolved CO₂. Multivariate RDA explained substantial joint CO₂–N₂O variation (adjusted R² = 0.720 in LF and 0.668 in HF); nutrients retained large unique fractions in both campaigns, while the OM-associated fraction was larger in HF. Metagenomic profiles linked pore-water CO₂ to multiple carbon-processing and respiratory functions. Pore-water N₂O was less clearly associated with broad microbial-community turnover but showed stronger relationships with substrate balance and denitrification-related functional composition. Higher N₂O coincided with lower WDOC/NO₃⁻-N; CLR-based analyses further showed significant associations between N₂O and denitrification-related gene profiles, with the relative representation of nosZ versus nirK/nirS decreasing as N₂O increased. These patterns were consistent with greater incomplete-denitrification potential under relatively low carbon availability. Across three thin boundary layer (TBL) model parameterizations, estimated CO₂ emissions were consistently higher in the HF campaign, whereas the direction of the N₂O flux contrast varied among models. These findings highlight distinct environmental and microbial associations of CO₂ and N₂O across contrasting hydrological states in intermittent rivers.

117. 题目: Buoyancy and polarity driven accumulation of dissolved organic matter in the sea surface microlayer during a phytoplankton bloom
文章编号: N26090301
期刊: Biogeosciences
作者: Jasper Zöbelein, Shubham Sawle, Gernot Friedrichs, Mariana Ribas-Ribas, Carola Lehners, Katharina Paetz, Maximilian Pflaum, Hannelore Waska
更新时间: 2026-09-03
摘要: . The sea surface microlayer (SML) is only 1–1000 µm thick but resembles a biologically and geochemically very active boundary that modulates the exchange of energy and matter between the ocean and atmosphere. Globally, the SML accumulates up to 200 Tg C yr−1 of organic matter, comparable to sedimentation rates on the oceans' seafloor. Yet, the mechanisms governing the accumulation and transformation of dissolved organic matter (DOM) in the SML remain poorly understood. Exposed to rapid changes of physical, biological, and photochemical conditions, the organic matter pool in the SML often shows heterogeneous distribution patterns, and a clear differentiation between SML and underlying water (ULW) is not always captured during in situ observations. In our mesocosm study, we initiated a phytoplankton bloom under controlled conditions, excluding physical influences like currents, waves, and precipitation. We tested three major hypotheses for DOM enrichment and compartmentalisation in the SML: enhanced in situ biogenic production and processing; physicochemical sorting by polarity and buoyancy; and selective degradation. Our results revealed that buoyancy-driven enrichment of DOM in the SML, fueled by local phytoplankton exudates and their subsequent breakdown, is key to DOM accumulation in the SML during and after phytoplankton blooms. Untargeted ultrahigh-resolution mass spectrometry, complemented by functional group analysis via Fourier-transform infrared spectroscopy, showed that carbohydrate-like compounds were particularly enriched in the SML. We also found evidence for accumulation of hydrophobic DOM of biogenic origin, such as lipid-like and protein-derived compounds, but a related polarity-driven compartmentalisation seems to play only a minor role. Moreover, no selective bio- and photodegradation patterns in the SML compared to the ULW took place. We conclude that under exclusively biogenic conditions, sugars and sugar-related compounds are the main drivers of SML compartmentalisation, and we suggest that phytoplankton-induced “carbo-slicks” could be the pioneer stage of a succession of SML organic geochemistry in natural environments.

118. 题目: Valorization of N-doped biochar into Fe-Cu loaded carbon catalyst from electroplating wastewater: Structure regulation, adsorption performance, and catalytic properties
文章编号: N26090219
期刊: Bioresource Technology
作者: Fangfang Ye, Xiaoying Jin, Jiajiang Lin, Zuliang Chen
更新时间: 2026-09-02
摘要: The efficient removal and resource recovery of high-concentration heavy metals like Fe3⁺ and Cu2⁺ from electroplating wastewater remains a critical challenge. Herein, a sustainable closed-loop “adsorption-transformation-upcycling” strategy was proposed. Initially, a nitrogen-doped and CaO-activated pinewood biochar (N-aPBC) was synthesized via synergistic modification. Systematic characterization revealed that N-aPBC features a high specific surface area (188.79 m2 g⁻1), a hierarchical porous architecture, and abundant nitrogen-containing functionalities. Adsorption experiments demonstrated superior performance for Fe3⁺ and Cu2⁺, yielding maximum capacities of 287.40 and 61.88 mg g⁻1, respectively. Mechanistic investigations indicated that the adsorption followed the pseudo-second-order kinetic model and Langmuir isotherm, suggesting monolayer chemisorption. The primary removal mechanisms involved surface complexation via N/O-functional groups, coupled with electrostatic attraction and ion exchange. N species and defects tuned surface polarity and electronic structure. Subsequently, the spent adsorbent was calcined to produce a functional material (Fe-Cu-NaB). Electrochemical analyses confirmed that Fe-Cu-NaB exhibited lower charge transfer resistance and enhanced electrocatalytic activity. Notably, Fe-Cu-NaB enhanced the oxidative degradation capacity, achieving high removal rates of 93.64% for ciprofloxacin (CIP) and 65.88% for total organic carbon (TOC) in swine wastewater. This work provides a high-performance adsorbent for heavy metal remediation and establishes a viable pathway for the high-value reutilization of spent adsorbents as efficient catalytic materials.

119. 题目: Allochthonous particulate organic carbon in blue carbon ecosystems: Implications for accounting, stability, and policy
文章编号: N26090218
期刊: Journal of Environmental Management
作者: Anirban Akhand, Inés Mazarrasa, Stacey M Trevathan-Tackett, K M G Mostofa, Abhra Chanda, Hongbin Liu, Hiroshi Sakugawa, Si-Liang Li, Cong-Qiang Liu, Catherine E Lovelock, Paul Lavery, Hilary Kennedy, Peter I Macreadie
更新时间: 2026-09-02
摘要: Blue carbon ecosystems (BCEs) store a significant amount of organic carbon (OC) in their soils, including OC sequestered by other ecosystems and transported into these ecosystems, referred to as allochthonous OC. This study reviews the state-of-the-art knowledge on the abundance and sources (including still unexplored ones) of allochthonous particulate organic carbon (POC) and reviews the ways allochthonous POC is managed under the current blue carbon policy frameworks for carbon benefits accounting in blue carbon restoration and conservation projects. Based on a review of 102 studies, we find that 56 ± 25% of the soil organic carbon (SOC) deposits in BCEs are allochthonous POC, most commonly identified as originating from terrestrial ecosystems, seston and macroalgae. Whether allochthonous POC should be included in blue carbon accounting is a matter of debate among the scientific community, due to the risks of overestimating carbon benefits and double-counting. Consequently, it is often excluded from voluntary carbon markets, but its inclusion can be justified given the role of BCEs in stabilising OC that may otherwise be remineralised. Based on existing knowledge, a deeper understanding of the stability and behaviour of different types of allochthonous POC under varying environmental conditions is needed to assess whether and to what extent these fractions can be counted toward carbon benefits.

120. 题目: Texture-associated DOM transformation links methane accumulation with arsenic mobilization in paddy soils
文章编号: N26090217
期刊: Journal of Hazardous Materials
作者: Chengcheng Jia, Shuqiong Kong, Min Cai, Yi Wang, Xiaguo Wei, Weiji Wu, Junxia Zhang, Haotian Song, Hongchen Jiang
更新时间: 2026-09-02
摘要: Arsenic (As)-contaminated paddy soils are important interfaces where methane (CH4) production and As mobilization occur concurrently, yet the role of soil texture in coupling these processes through dissolved organic matter (DOM) transformation and microbial activity remains unclear. Loam and silt paddy soils from the Jianghan Plain, China, were examined using geochemical analyses, DOM characterization, microbial profiling, metagenomics, quantitative PCR (qPCR), partial least squares path modeling (PLS-PM), and anaerobic microcosms. Loam soils contained less solid-phase As and Fe but more porewater As and Fe than silt soils. Their mean CH4 concentration was 8.7-fold higher (91.66 vs 10.59 μmol/kg). Loam porewater DOM showed greater humification and aromaticity, and humic-like components were positively correlated with As(III), whereas highly aromatic, polyphenolic, and highly unsaturated molecules were negatively correlated with CH4, suggesting preferential transformation of these compounds during CH4 emissions and As mobilization. Methanogenic and CH4-cycling archaea, including Methanobacterium, Methanosaeta, Methanosarcina, and Candidatus Methanoperedens, together with Fe/As-reducing taxa such as Geobacter, were more abundant in loam soils. Genes related to CH4 cycling and As metabolism were also detected. In microcosms, CH4 concentrations were 84.9% higher in loam soils and positively correlated with As(III) (R = 0.337, p < 0.001). Higher mcrA, ANME-mcrA, and arrA copy numbers and their positive intercorrelations further indicated greater functional potential for methanogenesis, anaerobic methane oxidation, and As reduction. Overall, soil texture indirectly regulates CH4 emissions and As mobilization by reshaping soil physicochemical conditions, DOM reactivity, and microbial functional niches.