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321. 题目: Dissolved organic matter composition and mineral surface chemistry modulate organic retention and formation of mineral associated organic matter
文章编号: N26081604
期刊: Geoderma
作者: Zongtang Yang, Lars Thomsen, Feike A Dijkstra, Georg Guggenberger, Balwant Singh
更新时间: 2026-08-16
摘要: The interaction between dissolved organic matter (DOM) and minerals governs OM stabilisation in soils. Heterogeneous composition of DOM and diverse mineral surface characteristics in soils make it challenging to determine reaction mechanisms at mineral-organic interfaces. To determine the role of DOM and mineral characteristics in the formation of mineral associated organic matter (MAOM), we conducted adsorption experiments using four DOM extracts from pine, Eucalyptus, pasture and wheat residues and six minerals (i.e., kaolinite, montmorillonite, goethite, birnessite, ferrihydrite and allophane) with contrasting charge characteristics, structural order and specific surface area. Poorly crystalline and amorphous minerals generally adsorbed larger amounts of DOM than crystalline oxides and phyllosilicates. The adsorption sequence of functional groups differed with mineral surface chemistry, but C=C/C=O, C-O-C and C-O groups were consistently the most abundant adsorbed moieties. Adsorption involved both mineral-organic and organic-organic interactions, with the latter appearing with increased OM loading, yielding different mineral-OM assemblages depending on OM loading and mineral characteristics. Carboxylic, aromatic and aliphatic organic components predominantly adsorbed on the surfaces of ferrihydrite, allophane, goethite, and kaolinite, whereas quinone and phenolic organic components were preferentially adsorbed on birnessite and montmorillonite. Variations in the molecular composition within DOM also modulated adsorption behaviour at mineral-organic interfaces. The adsorption capacity of wheat DOM on mineral surfaces was lower than that of the other DOM due to its less abundance of reactive functional groups. Our results provide a mechanistic basis for understanding how DOM composition and mineral surface properties regulate the formation of MAOM under acidic conditions.

322. 题目: Zn isotope fractionation during sorption on alumina mediated by humic acid
文章编号: N26081603
期刊: Geochimica et Cosmochimica Acta
作者: Wenxian Gou, Xiaoyu Li, Ying Chen, Lan Jiang, Zhaofeng Zhang, Yi Huang
更新时间: 2026-08-16
摘要: Dissolved organic matter (DOM) is ubiquitous in surface environments, yet its influence on Zn stable isotope fractionation at mineral–water interfaces remains poorly constrained, impeding a thorough understanding of Zn isotope behavior in natural systems. This study uses humic acid (HA) as an operational analogue of DOM to investigate HA effects on Zn isotope fractionation during sorption onto γ-alumina. High-precision Zn isotope analyses, combined with X-ray diffraction, transmission electron microscopy, and X-ray absorption fine-structure spectroscopy, reveal that the HA effect is pH-dependent and closely associated with molecular-scale Zn surface speciation. Under acidic conditions, Zn is retained as ≡AlOZn inner-sphere complexes, and HA has little effect on either Zn surface speciation or isotope fractionation. At circumneutral to alkaline pH, however, HA suppresses Zn-Al layered double hydroxide (LDH) formation and redirects Zn toward ≡AlOZn inner-sphere complexation, increasing Zn isotope fractionation from near zero in HA-free systems to 0.44 ± 0.03‰ in HA-rich systems. This increase is consistent with the greater bonding reorganization required to form tetrahedral ≡AlOZn complexes from aqueous Zn than to incorporate Zn into octahedral Zn-Al LDH structures. The HA-based findings may capture, to a first order, DOM effects in systems dominated by carboxyl and phenolic hydroxyl groups, as salicylic acid substitution experiments indicate that organic ligands with similar O-bearing functional groups exert similar controls on interfacial Zn isotope fractionation. These results define a mechanistic end-member constraint for DOM-Al oxide interactions and their role in Zn isotope systematics in organo-mineral and soil–river weathering systems.

323. 题目: Production, Biodegradation, and Recalcitrance of Organic Carbon from Cultivated Saccharina latissima in Norway
文章编号: N26081602
期刊: Environmental Science & Technology
作者: Luiza Neves, Sebastian Aker, David Aldridge, Deni Ribičić, Anders Brunsvik, Ole Jacob Broch, Jorunn Skjermo, Murat Van Ardelan
更新时间: 2026-08-16
摘要: Particulate (POC) and dissolved (DOC) organic carbon released during macroalgae cultivation has been shown to lead to carbon burial and export to the open ocean and deep sea. The recalcitrant portion of the DOC (RDOC) is a critical contributor to carbon sequestration and a major knowledge gap. We investigate the production and bioavailability of DOC released from Saccharina latissima, a primary cultivar in Europe, with a focus on RDOC quantification. DOC release rates were 0.5–1.4 mg C g(dw)−1 h–1 within 24 h, and concentrations stabilized after 187 days of biodegradation, at 37–79% (mean 58%) from initial levels. The kelp released 920 (17%) unique compounds, including large quantities of sulfur-containing molecules (CHOS, CHONS). Increasing recalcitrance was observed in kelp and control treatments, despite small variations in CRAM molecules. Microbial biodegradation generated 1,805 (34%) new molecules, including 1,207 in the recalcitrant DOM fraction. Island of Stability (IOS) analysis revealed an intensity-weighted abundance of 0.2% RDOC in kelp treatments, with persistence on geological time scales. Beyond its biomass applications, macroalgae cultivation enables scalable CO2 sequestration in the oceans through RDOC production from continuous release and degradation of DOC and POC during grow-out, in itself a value-added product.

324. 题目: Mechanistic insights into enhanced permanganate activation by biochar derived from aluminum sludge: Critical roles of persistent free radicals and alumina
文章编号: N26081601
期刊: Environmental Research
作者: Zhongquan He, Yin Wei, Haonan Chen, Junyu Wu, Cheng Han, Xilei Jia, Junfeng Wang, Weiwei Hou, Chuanliang Zhao, Lanlan Liang, Liwei Yang
更新时间: 2026-08-16
摘要: Permanganate (Mn(VII)) is widely used as the oxidant in water treatment, yet its relative stability limits its reactivity toward refractory organic contaminants. In this study, we proposed a novel “waste-to-value” strategy by pyrolyzing aluminum sludge from water treatment plants to alumina-biochar composite catalysts (Al2O3@BCs), aimed at enhancing Mn(VII) activation for the degradation of phenolic pollutants. The Al2O3@BC pyrolyzed at 600°C exhibited the highest catalytic performance, achieving 100% phenol (PE) degradation within 15 min. During the Mn(VII) activation process, Al2O3@BC exhibited a dual-function mechanism by simultaneously promoting Mn(III) generation and enhancing the oxidation potential of Mn(VII). The carbon-centered persistent free radicals (PFRs) on the biochar in Al2O3@BC significantly promoted the reduction of Mn(VII) to reactive Mn(III), while the alumina in Al2O3@BC improved the oxidation potential of Mn(VII) from 0.46 V to 0.54 V. These two pathways contributed comparably to PE degradation. Density functional theory (DFT) calculations revealed that the Mn(VII) was reduced to reactive Mn(III) by electron donation from PFRs, in which the type of carbon-centered PFRs exhibited the highest Mn(VII) reduction activity. The Al2O3@BC catalyst exhibited excellent resistance to environmental matrix interference and efficiently degraded various organic contaminants during actual water purification. Furthermore, the continuous-flow system and quantitative analysis based on life cycle assessment (LCA) revealed that the Mn(VII)/Al2O3@BC system possesses significant environmental advantages and technical feasibility. This study highlights the sustainable utilization potential of aluminum sludge and offers new insights into the activation mechanism of Mn(VII) in water treatment.

325. 题目: Molecular fractionation and transformation of dissolved black carbon on hematite facets: implications for sunlight-driven photodegradation of antibiotics in aquatic environments
文章编号: N26081516
期刊: Bioresource Technology
作者: Jinxi Xie, Honglong Zhang, Ming Chen, Shengjun Wu
更新时间: 2026-08-15
摘要: Dissolved black carbon (DBC), the mobile and reactive fraction released from biochar, can adsorb onto iron oxides and alter their photochemical reactivity, thereby influencing the photochemical transformation of coexisting organic pollutants. However, how DBC molecular composition, which varies with pyrolysis temperature, governs its interactions with different hematite facets, and how these interactions in turn affect organic pollutant photodegradation remains unclear. Herein, hematite nanocrystals exposing {001}, {100}, and {012} facets, and two DBCs pyrolyzed at 300 ℃ and 500 ℃ (DBC300 and DBC500), were employed to investigate DBC molecular fractionation and transformation, and their impacts on sunlight-driven tetracycline hydrochloride (TCH) photodegradation. FT-ICR MS analysis showed that the intrinsic molecular composition of DBC primarily determined its molecular fractionation and transformation, whereas hematite crystal facets mainly regulated the extent of these processes. DBC300 underwent adsorption coupled with more extensive molecular transformation, whereas DBC500 was dominated by adsorption-driven molecular fractionation. Distinct facet-dependent behaviors were observed, with {001}-dominated hematite nano-plates favoring adsorption-driven molecular fractionation, {100}-dominated hematite nano-rods exhibiting the highest surface area-normalized adsorption density, and {012}-exposed hematite nano-cubes showing the greatest potential for molecular transformation. Photodegradation experiments showed that DBC adsorption substantially inhibited TCH photodegradation on all hematite nanocrystals. Although the retained low-molecular-weight aromatic fractions slightly enhanced light harvesting, adsorbed high-MW and oxygen-rich DBC fractions primarily inhibited hematite photochemical reactivity by suppressing interfacial charge transfer and altering reactive intermediate generation. These findings highlight the role of mineral-organic interactions in regulating contaminant fate in iron-rich aquatic environments and reveal the emerging challenges associated with biochar applications.

326. 题目: Astragalus Membranaceus Residue-Derived Biochar Supporting Atlantibacter hermannii XJ08 for Synergistic Multimetal Immobilization and Soil Quality Improvement
文章编号: N26081515
期刊: ACS ES&T Engineering
作者: Kailu Zhang, Jianshan Huang, Han Hu, Lixue Qiu, Fuxing Wu, Lixun Zhang
更新时间: 2026-08-15
摘要: Soil contamination by Cd and Pb poses significant risks to ecological security and human health. Herein, a series of modified biochar (AMBC) were synthesized from Astragalus membranaceus residues, and subsequently employed as carriers of Atlantibacter hermannii XJ08 to construct biochar-microbe composites for soil remediation. Among the tested materials, brown sugar-modified AMBC (BS-AMBC) showed the highest microbial loading capacity (9.2 × 107 CFU·g–1) and superior Cd and Pb adsorption performance. The BS-AMBC@A. hermannii XJ08 composite effectively reduced DTPA-extractable Cd and Pb concentrations to 0.26 mg·kg–1 and 68 mg·kg–1, respectively. Notably, > 56% of labile fractions (water-soluble/acid-soluble) were transformed into stable oxidizable and residual forms, indicating persistent metal immobilization. In addition, the composite significantly improved soil quality, increasing soil organic matter, cation exchange capacity, and available nitrogen/phosphorus/potassium to 22.3 g·kg–1, 30.4 cmol·kg–1, and 122/44.0/235 mg·kg–1, respectively. Urease, phosphatase, and dehydrogenase activities were markedly elevated by 243%, 527%, and 685%, respectively. Microbial community analysis further revealed the enrichment of functional taxa (e.g., Cytobacillus) associated with heavy metal immobilization, alongside the regulation of key metabolic pathways involved in biogeochemical cycling. This study demonstrates a sustainable approach for valorizing medicinal plant residues into high-performance biochar-microbe composites, offering an effective strategy for the ecological restoration of multimetal contaminated soils.

327. 题目: Laboratory combustion-induced transformation of pyrogenic dissolved organic matter from vegetation and its impact on disinfection byproduct formation
文章编号: N26081514
期刊: Water Research
作者: Jingyi Zeng, Meng Jiao, Kathleen Murphy, Carlos Afonso, Marie Hubert-Roux, Yingying Xiang, Jean-Philippe Croué
更新时间: 2026-08-15
摘要: Wildfires can threaten the drinking water quality by introducing pyrogenic dissolved organic matter (PyDOM) into watersheds. However, the role of flammable vegetation distributed across forest strata, especially lower-stratum fuels, in shaping PyDOM composition and its consequences for source water remains unclear. Five representative French forest plant species—oak (canopy), pine (canopy), heather (understory), gorse (shrub) and fern (herb)—were combusted at 550°C to generate PyDOM. Compared with DOM extracted from unburned plants, PyDOM showed 5.2 to 59.8-fold higher relative abundances of condensed aromatic molecular features (CAs), accompanied by a decrease in dissolved organic carbon (DOC) content and an increase in inorganic ion concentrations, including halides. Notably, PARAFAC modelling isolated two hydroxybenzoic acid-like components (m- and o- isomers) with spectral properties matching reported pure organic compounds. These components were predominantly present in PyDOM extracted from gorse, with the lowest abundance observed in burned fern and heather. Combustion-induced changes in DOM were highly vegetation-dependent. PyDOM from heather, oak, and pine contained greater CA abundances than that from other plants. Increased precursors of halogenated organic formulas (HOCs) were mainly observed in burned oak and pine. Chlorination of PyDOM enhanced the formation of brominated and nitrogenous DBPs, likely correlated to elevated levels of black nitrogen (BN) and bromide. Nitrogenous DBPs accounted for over 50% of identified DBPs in both PyDOM from gorse and heather. Our findings indicate how vegetation across forest strata interacts with high-temperature combustion to potentially reshape DOM composition and DBP formation potential relevant to forested source waters.

328. 题目: Topographic and Climatic Determinants of Soil Organic Carbon Across Landscapes: A Meta‐Analysis
文章编号: N26081513
期刊: Land Degradation & Development
作者: Vishal Sharma, Syed Hujjat ul Baligah, Tajamul Islam Shah, Shahid Shuja Shafai, Owais Bashir, Syed Sheraz Madhi, S Naresh Kumar, Ayyandar Arunachalam, Shabir Ahmed Bangroo
更新时间: 2026-08-15
摘要: The soil is the greatest natural store of organic carbon, holding between 1500 to 1550 Pg C of organic carbon at the top 100 cm of the soil globally—roughly twice the carbon pool in the atmosphere. The spatial distribution of this stock is controlled by a complex chain of controls: topographic position regulates the hydrological redistribution, microclimate and erosion at the landscape scale and climatic variables, such as mean annual temperature (MAT), mean annual precipitation (MAP), aridity index and seasonality of precipitation, determine the envelope of the topographic effects at the regional and continental scale. Although the primary literature is growing at a very fast rate, no quantitative synthesis has to date concurrently evaluated the complete set of topographic variables, such as slope gradient, aspect, elevation, topographic curvature and the topographic wetness index (TWI), alongside the influences of climate and processes of soil carbon fractionation. This meta‐analysis screened 1339 peer‐reviewed studies (1964–2024) following PRISMA 2020 guidelines; of these, 26 reported extractable correlation coefficients and were included in the quantitative meta‐analysis (slope: k = 15; elevation: k = 11). The study addresses the following questions: (i) to quantify the mean effect sizes and between‐study heterogeneity of topographic and climatic controls on SOC; (ii) to specify the moderating variables that justify the extreme heterogeneity ( I 2 > 98%) and (iii) to define the critical gaps in the research. Fisher r ‐to‐ z meta‐analysis showed that slope gradient has a borderline‐significant positive mean effect on SOC ( μ̂ = 0.238; 95% CI: 0.001–0.474; k = 15; I 2 = 98.1%; p = 0.049) and a non‐significant effect of altitude on SOC ( μ̂ = 0.130; 95% CI: −0.178–0.437; k = 11; I 2 = 98.7%; p = 0.409). Wide heterogeneity of the two analyses indicates dominant expression of moderating roles of ecosystem type, land use, soil texture and mineralogy. The topographic aspect has the strongest topographical dominance: the northward slopes accrete 1.9–3.2 times more SOC compared to southward counterparts at the same altitude. TWI—an index that combines terrain location stance and hydrological connection—emerges as the most effective terrain predictor of SOC in digital soil mapping (DSM) models and explains 15%–38% of the landscape‐scale variance in SOC. The current particulate organic carbon (POC) versus mineral‐associated organic carbon (MAOC) fractionation model shows that erosional summit locations selectively lose labile POC and depositional foot‐slope locations accrue high levels of MAOC by means of organo‐mineral complexation with Fe/Al oxides. In the IPCC AR6 warming scenarios (1.5°C–2.0°C) the change in SOC stocks is expected to be an 8%–12% reduction in the global stocks of the soils in fine‐textured foot‐slope and coarse‐textured summit soils. Such findings offer a quantitative basis of digital soil mapping, land‐use planning and the 4 per mille carbon sequestration programme, which are directly related to the national carbon accounting under NDC schemes in concert with SDG 13 and SDG 15.

329. 题目: Overlooked sulfur moieties in leaf litter drive the divergent fates of Cu and Cd during DOM humification
文章编号: N26081512
期刊: Journal of Hazardous Materials
作者: Xinchao Zhang, Lexuan Wang, Chaoyue Tai, Meng Gong, Yuanyuan Pei, Lin Gu, Chenxi Liu, Hanlin Zhang
更新时间: 2026-08-15
摘要: Early humification of leaf litter generates dynamic dissolved organic matter (DOM) that regulates heavy-metal mobility at soil–water interfaces, yet the role of sulfur-containing moieties under oxygen-limited conditions remains unclear. Here, FT-ICR MS and fluorescence spectroscopy were used to track DOM evolution and its interactions with Cu(II) and Cd(II). Fresh DOM was dominated by protein-like component, associated with aliphatic N/S species, whereas humified DOM was enriched in humic-like components correlated with aromatic and lignin-like sulfur molecules. The progressive humification increased the Cu(II) complexation constant (logKM) from 3.46 to 5.38, which was attributed to the accumulation of reduced sulfur species (O/S < 5) in the aromatic humic matrix. These groups acted as redox-active centers, promoting Cu(II) reduction to Cu(I) (up to 82.4%) and subsequent desulfurization, with a tendency toward Cu2S sedimentation and irreversible immobilization in quartz-column simulations. By contrast, Cd(II) showed moderate affinity (logKM≈3.0–3.4) and mainly targeted protein-like sites. Molecular and transport analyses showed that Cd(II) mainly interacted with oxidized S/O sites and promoted condensation, whereas fresh DOM favored Cd retention and humified DOM enhanced Cu immobilization. These results reveal humification-driven differences in metal fate and inform predictions of heavy-metal stability and ecological risk at soil–litter interfaces.

330. 题目: DOM-mediated interaction of DOM-enzyme-pollutants affected the toxicity of combined aged tire wear particles (aged-TWPs) and polyfluoroalkyl substances (PFASs) in soil under successive extreme weather stress
文章编号: N26081511
期刊: Journal of Environmental Management
作者: Xin Wang, Yulian Ma, Xinyu Yang, Yue Sun, Wenzhuo Sui, Yunhong Pu, Qianzhi Zeng, Yaxuan Wu, Bowen Yang, Xinran Su, Shuang Li, Linna Shi, Shengnan Shi, Zheng Gong
更新时间: 2026-08-15
摘要: Extreme weather stress is posing growing threats to ecosystems, as they directly disturb soil moisture and affect the toxicity of pollutants, thereby increasing ecological risks. This study investigated how successive extreme climate stress (heatwave, heatwave-drought, and flood) affected the toxicity of co-exposed aged tire wear particles (aged-TWPs) and polyfluoroalkyl substances (PFASs). Results revealed that the combined contamination (COM) significantly altered bacterial diversity and community composition, with the responses varying across the three successive extreme weather stress. Under three extreme weather stress, compared to the control group, the COM did not significantly induce the oxidative stress and cellular membrane damage caused by the individual contamination. The COM increased the aromaticity, hydrophobicity, and humification degree of dissolved organic matter (DOM), particularly under flood stress. The terrestrial esters within DOM significantly shifted the bacterial community. Under three extreme weather stress, the COM increased activities of selected C/N/P cycling enzymes. Interaction of DOM-Enzyme-Pollutants analysis confirmed that DOM, particularly from COM under flood stress, counteracted pollutants-induced conformational loosen of extracellular enzymes in C/N/P cycles and restored enzyme activities. This study provided novel insights into effects of co-exposure of PFASs and aged-TWPs on soil ecosystem under successive extreme weather stress.

331. 题目: Integrating soil organic carbon loss into building life cycle assessment and urban planning: implications for urban sustainability practice
文章编号: N26081510
期刊: Journal of Environmental Management
作者: Gerasimos Christoforatos, Kim Pickering, Louis A Schipper
更新时间: 2026-08-15
摘要: Urban expansion depletes soil organic carbon (SOC) stocks through topsoil disturbance, removal, and sealing, contributing to carbon emissions and climate change. However, SOC considerations are largely absent from urban sustainability practice. This study integrates SOC loss into two distinct assessment domains—urban planning and building life cycle assessment (LCA)—to evaluate its magnitude at both the urban and building levels and investigate potential pathways to mitigate it. At the urban level, a business-as-usual urban expansion scenario for Auckland, New Zealand, is modelled and compared with a SOC-aware alternative that prioritizes development on low-SOC soils. The SOC-aware scenario was found to conserve 14.6% of SOC (0.092 MtCO2-eq), equivalent to 20-46% of the national embodied impact reduction target for the construction sector, demonstrating the significance of SOC-aware planning. At the building level, SOC loss is introduced as a potential LCA module, examining four residential typologies—apartment, townhouse, double-storey detached, and single-storey detached—to evaluate its magnitude relative to conventional embodied impacts. The results indicate that SOC loss can account for up to 70.9% of conventionally assessed embodied impacts in extreme cases (for single-storey detached house built on Organic Soils), while remaining a substantial contributor in all other cases—on average representing 0.9%, 4.6%, 9.3%, and 21.5% of conventional embodied impacts for apartment, townhouse, double-storey detached, and single-storey detached houses, respectively. Overall, integrating SOC loss into decision-relevant assessments reveals its substantial magnitude and offers an opportunity to reduce it, while underscoring the need for improved soil characterization in areas zoned for urban expansion.

332. 题目: DOM evolution and microbial function during anaerobic digestion under supplementing Fenton sludge: A comparative study
文章编号: N26081509
期刊: Journal of Environmental Chemical Engineering
作者: Minhui Cai, Ruize Xia, Zheng Wang, Jun Li, Qing Zhou, Yan Li, Wentao Li, Aimin Li
更新时间: 2026-08-15
摘要: Certain Fe(III) compounds are utilized to stimulate dissimilatory iron reduction (DIR), thereby accelerating the transformation of dissolved organic matter (DOM) during anaerobic digestion. The effects of four specific Fe(III) compounds—Fenton sludge (FS), ferrihydrite, Fe2O3, and Fe(OH)3—on DOM evolution and microbial function dynamics during anaerobic digestion were investigated in this study. Batch experiments revealed that the FS exhibited superior performance in DIR efficiency and DOM transformation compared to other Fe(III) compounds, which is attributed to its relatively low crystallinity that enhances bioavailability and the higher predicted relative abundance of pilA gene, which is consistent with enhanced extracellular electron transfer. Combined size exclusion chromatography and fluorescence excitation emission matrix analysis demonstrated that the FS effectively degraded and transformed medium molecular weight humic-like substances. Furthermore, pathway analysis confirmed that the FS augmented acidification efficiencies, triggered by elevated activity of the propionate CoA-transferase pathway. Five genera, including Paludibacter, Macellibacteroides, Bact-08, TM7a, and Clostridium sensu stricto 12, were identified as keystone genera via network analysis. These genera maintained the bacterial community’s functional stability through their potential involvement in the DIR process and regulation of organic matter metabolism. Overall, these findings highlight FS as a promising Fe(III) source that drives efficient DIR-coupled DOM transformation, suggesting its potential for the resource recovery of Fenton sludge.

333. 题目: National Evidence of Depth‐Dependent Stabilization and Controls of Soil Organic Carbon in Dryland Croplands
文章编号: N26081508
期刊: Global Change Biology
作者: Yuchen Wei, Xin Zhao, Wenting Feng, Hongyong Sun, Jinfeng Chang, Hong Chen, Ji Chen, Xiaowei Guo, Di He, Feng Liu, Alain F Plante, Zhou Shi, Zhaoliang Song, Raphael A Viscarra Rossel, Lewis Walden, Enli Wang, Mingming Wang, Liujun Xiao, Su Ye, Shuai Zhang, Hangxin Zhou, Zhongkui Luo
更新时间: 2026-08-15
摘要: Soil organic carbon (SOC) underpins agricultural sustainability and the terrestrial carbon cycle, yet its vertical distribution and stabilization across soil depth remain poorly constrained at large spatial scales. Here, we present a nationwide, depth‐resolved dataset of SOC and mineral‐associated organic carbon (MAOC)—the more persistent SOC fraction—from 365 dryland cropland sites across China, sampled to 2 m depth. Contrary to the classic model of exponential SOC decline, 46% of profiles exhibited uniform or increasing SOC and MAOC with depth, highlighting a substantial role of subsoil carbon. MAOC accounted for more than half of total SOC in most layers, but its relative contribution declined below 1 m, challenging the assumption that subsoil carbon is inherently more stable. Clay + silt content was the strongest predictor for SOC, MAOC, and MAOC/SOC across depths, while vegetation productivity, a proxy for carbon inputs, was positively associated with all three. The influence of clay + silt on MAOC accumulation weakened with depth, and the positive interaction between vegetation productivity and clay + silt weakened or diminished from surface soils to deeper layers. These patterns indicate a transition from joint regulation by carbon inputs and mineral surfaces in surface soils toward an increasingly input‐limited regime in deeper layers, as inferred from the depth‐dependent changes in the relative importance of vegetation productivity and fine particle content. National mapping estimated ~19.9 Pg SOC stored within the 0–2 m layer in China's dryland croplands, with 75% below 0.3 m and 60% stabilized as MAOC. These results provide a benchmark for depth‐explicit SOC accounting and highlight the importance of aligning carbon inputs with soil mineralogy to enhance whole‐profile carbon stabilization and climate mitigation.

334. 题目: Evaluating the Molecular Compound Heterogeneity of Dissolved Organic Matter (DOM) during Coupled Release-Diffusion Kinetic Processes in Soil
文章编号: N26081507
期刊: Environmental Science & Technology
作者: Wenxia Wang, Rong Li, Qianting Ye, Peng Liao, Zhifang Xiao, Shuling Chen, Zhenqing Shi
更新时间: 2026-08-15
摘要: Soil dissolved organic matter (DOM) leaching critically regulates subsoil carbon stocks, yet how molecular heterogeneity governs the coupled release-diffusion kinetics remains elusive. Here, we employed a novel column system with in situ porewater samplers and Fourier transform ion cyclotron resonance mass spectrometry to resolve DOM molecular behaviors at unprecedented resolution. By establishing the compound-specific interfacial release preference index and apparent diffusive mass-transfer coefficient, coupled with interpretable machine learning algorithms, we revealed strong molecular-level selectivity in both processes: the O/C ratio and oxygen content predominantly controlled interphase release, while the aromaticity index and double bond equivalent governed intrapore diffusion. These findings challenge the simplification of bulk dissolved organic carbon in current soil carbon turnover models and provide estimated molecular parameters essential for mechanistically predicting subsoil carbon stability under changing climate conditions.

335. 题目: Freeze–Thaw Cycles Greatly Affect the Conjugative Transfer of Antibiotic-Resistant Genes: Effects of the Secretion of Extracellular Polymeric Substances
文章编号: N26081506
期刊: Environmental Science & Technology
作者: Zhengmao Li, Jianmei Qin, Lei He, Chenyi Nie, Fuyang Liu, Yanghui Hou, Meiping Tong
更新时间: 2026-08-15
摘要: Freeze–thaw (FT) cycle, a ubiquitous and important physical process in natural environments, may influence the horizontal gene transfer (HGT) process of antibiotic-resistant genes (ARGs), yet its impact and underlying mechanisms remain unclear. This study investigated the impact and mechanisms of FT cycles on ARG conjugative transfer among intra- and interspecies under different solution ionic strength conditions. The results showed that despite ionic strengths and species pairs, different FT treatment cycles induced diverse influences on ARG conjugation frequency with inhibition effect of 1 FT cycle (decreased by 3.5–76-fold) and facilitation effect of 2 and 3 FT cycles (promoted by 2–27-fold). The reduced conjugation frequency after 1 FT treatment cycle is mainly attributed to energy deficiency caused by the starvation process during FT treatment. The enhanced cell–cell adhesion induced by the increased hydrophobicity and secretion of bacterial extracellular polymeric substances (EPS) facilitated the formation of conjugative pilus, primarily promoting the ARG conjugative transfer process after 2 and 3 FT treatment cycles. The results of our study clearly show that FT cycles (intensified by the ongoing climate change) exhibit profound influence on the dissemination of ARGs, which helps understand and predict ARG risks in different natural environments.

336. 题目: Air-Mass Influence, Radiation, and Melt-Season Dynamics Jointly Shape Dissolved Organic Matter Composition and Radiocarbon Age in Glacier Outflows on the Tibetan Plateau
文章编号: N26081505
期刊: Environmental Science & Technology
作者: Chen Huang, Mo Wang, Xiaolong Zhang, Frank-Thomas Koch, Christoph Gerbig, Hongxing Jiang, Baiqing Xu, Gerd Gleixner
更新时间: 2026-08-15
摘要: Glacier melt increasingly delivers bioavailable yet radiocarbon-depleted dissolved organic matter (DOM) to headwaters, but controls on DOM molecular composition and radiocarbon signatures remain unclear for the Tibetan Plateau. We coupled ultrahigh-resolution mass spectrometry with Δ14C measurements for 30 samples from 16 glacier outflows, including three ablation-season time series across contrasting climatic settings. DOC concentrations were uniformly low, but DOM composition was highly heterogeneous. Multivariate analyses identified longitude and shortwave radiation as primary regional correlates, while marked differences among neighboring outlets indicated strong local controls. Seasonal DOM patterns varied by site: at the monsoon-influenced Rongbuk Glacier on the northern slope of Mount Everest, DOM shifted from lipid-rich to more lignin-, tannin-, and aromatic-enriched compositions as inorganic deposition indicators increased, consistent with enhanced allochthonous influence; however, Δ14C became more modern over the season. In contrast, the westerly-influenced, high-radiation Xiongcai Glacier showed comparatively stable DOM composition but elevated and dynamic peptide-like signals. Across the Δ14C subset (n = 23), Δ14C correlated negatively with lipid-like contributions, revealing an underappreciated “old-but-potentially labile” component. These results show that regional climate, local catchment setting, and melt-season progression jointly govern the export of mixtures of young and old, labile and compositionally complex DOM.

337. 题目: Increasing Biochar Yield in Pyrolysis by Adding Ash
文章编号: N26081504
期刊: Environmental Science & Technology
作者: Jannis Grafmüller, Michael Tobler, Philipp Vögelin, Thomas D Bucheli, Hans-Peter Schmidt, Nikolas Hagemann
更新时间: 2026-08-15
摘要: Wood ash additives increase biochar yield in pyrolysis via catalysis by alkali and alkaline earth metals. However, it remains unclear how ash and biomass properties govern the magnitude of this catalytic effect. Here, we pyrolyzed pelleted and ash-amended woody and gramineous biomasses at 500–550 °C. At pilot scale, 5% (w/w) amendment of different ashes increased dry and ash-free biochar yield (ydaf) by 13–37% and carbon yield (yC) by 2–33% for woody feedstocks and decreased yields by 5–6% for grass or straw. Accordingly, mixing grass with softwood at increasing ratios reduced the effects of added ash. The yield increase depended on biomass type rather than on the intrinsic ash content of the biomass, as positive effects were observed even for woody feedstocks with a relatively high ash content, unlike gramineous biomass. Yield increases observed for different added ashes did not correlate with ash properties, pending further investigation. Toxic hexavalent chromium from ash additives was not detected in biochar, suggesting its reduction to nontoxic Cr(III) during biochar production. At industrial scale, ydaf increased by 11% and yC by 6% through adding 4% ash to landscaping wood, demonstrating the scalability of wood ash use. Adding ash to woody feedstock increased biochar production, pyrolysis economy, and carbon sink potential.

338. 题目: Heterotrophic integration enhances structural resilience of anammox granules through extracellular polymeric substance interface remodeling
文章编号: N26081503
期刊: Environmental Research
作者: Jinyan Wang, Shenbin Cao, Xing Li, Xiaoyan Fan, Rui Du
更新时间: 2026-08-15
摘要: Structural resilience of granular sludge is essential for maintaining stable partial denitrification–anammox (PDA) performance under long-term operational disturbances, yet the mechanisms governing resilience in mixed-trophic granules remain poorly understood. Here, heterotroph-integrated PDA granules were systematically compared with independently cultivated partial denitrification (PD) and anammox (AMX) granules to elucidate how heterotrophic integration influences granule stability. The integrated system established stable metabolic coupling, achieving a nitrate-to-nitrite transformation ratio (NTR) of 91.6% with concurrent ammonium removal. More importantly, after 70 operational cycles, the mean diameter of PDA granules decreased by 17.4%, compared with 29.2% for AMX granules, while the 0.5–1.0 mm fraction remained dominant. PDA sludge also displayed the highest aggregation rate constant (8.45 h-1), indicating rapid structural recovery. Multiscale analyses suggested that these improvements were associated with extracellular polymeric substance (EPS) interface remodeling rather than increased EPS production alone. Heterotrophic integration promoted a tightly bound and compositionally balanced EPS matrix, with the T-EPS fraction reaching 86.1%, together with diversified protein secondary structures and an O/N-rich surface. These features potentially strengthened hydrogen bonding, hydrophobic interactions, polymer bridging, and other non-electrostatic cohesive forces. Concurrently, mixed-trophic community assembly increased microbial richness and established complementary interactions between heterotrophic denitrifiers and anammox bacteria. Collectively, these results support a proposed framework linking microbial community assembly, EPS interface remodeling, and structural resilience. This work identifies extracellular interface regulation as a potential strategy for improving biomass retention and operational robustness in low-carbon anammox-based wastewater treatment.

339. 题目: Soil organic carbon patterns and carbon‑iron binding at different slope positions on eroded slopes in subalpine regions
文章编号: N26081502
期刊: Catena
作者: Meihua Sheng, Peng Wang, Qinqing Yang, Ziye Xu, Zhuojun Li, Shenghao Ai
更新时间: 2026-08-15
摘要: Soil erosion resulting from mountain excavation remains an important factor contributing to soil organic carbon (SOC) loss in subalpine regions. After an extensive period of ecological restoration, the slope continues to experience serious soil loss. As a result, the storage and stability of SOC in the eroded slope are being severely compromised. However, the studies of soil carbon loss, carbon‑iron binding, and carbon fractions patterns caused by changes in slope position remains constrained. Here we quantified the soil erosion and SOC concentration at different slope positions of eroded area in the Qinghai-Tibet Plateau. We investigated the influence of soil aggregates, iron oxides, and enzyme activities on the preservation and decomposition of organic carbon, as well as the migration and transformation of particulate organic carbon (POC), mineral-associated organic carbon (MAOC) and iron-bound organic carbon (Fe-OC) during soil erosion. We show that the middle slope experiences the most severe erosion-induced carbon loss across the entire slope, where enzymatic activity remains active. The POC concentration of the slope is 55% lower than the MAOC concentration. Despite the loss occurs both in MAOC and POC due to intensified slope erosion, the mineral protection is still an important way to preserve SOC at eroded slopes in subalpine regions. Furthermore, the increase of small particle size aggregates (proportion of aggregates 2–0.25 mm) within the soil may reduce the carbon‑iron binding. While the activities of hydrolase and oxidase increased instead in the middle slope, which exhibits the highest erosion potential and the lowest aggregate stability, thereby accelerating the turnover of POC and Fe-OC. Soil water content, soil pH, small aggregate content and enzyme activities are critical indicators affecting the SOC sequestration and transformation on subalpine cut slopes.

340. 题目: A Review of Atmospheric Black Carbon Research Progress in China
文章编号: N26081501
期刊: Atmospheric Environment
作者: Qi Zhou, Shunyao Wang, Shujun Bie, Junjie Cai, Yingjun Chen, Yuan Cheng, Xiang Ding, Jianwei Gu, Jie Li, Weijun Li, Dantong Liu, Jiaying Liu, Yue Liu, Jing Shang, Xiao Tang, Rui Tang, Yingze Tian, Jiandong Wang, Shuxiao Wang, Jing Wei, Yi Wei, Yaxin Xiang, Caiqing Yan, Fenfen Zhang, Zhouyang Zhang, Gan Zhang, Qiang Zhang, Yan Zhang, Guangcai Zhong, Mei Zheng
更新时间: 2026-08-15
摘要: Black carbon (BC) is an atmospheric pollutant that adversely affects air quality, global climate, and human health. As an important BC source region, China has achieved substantial emission reductions over the past decade through stringent clean air policies, offering a unique opportunity to study changes of BC sources and properties under rapid emission changes. Concurrently, BC research in China has progressed rapidly, shifting from studying emission sources toward atmospheric processes and health impacts. This review focuses on five key topics in BC research, including ambient concentrations, emission sources, atmospheric aging, mixing state, and health effects. Ground observation networks and gridded datasets have shown a significant decrease in BC concentrations due to clean air policies, particularly in Northern and Eastern China. Emission inventories and source apportionment studies consistently identified fossil fuel combustion as the dominant BC source in China. Laboratory, field, and modeling studies have advanced understanding of BC aging and mixing state. The health evidence from China has linked BC exposure to respiratory, cardiovascular, and neurological diseases. The rapid expansion and heterogeneity of datasets underscore the urgent need for measurement standardization and cross-regional dataset comparison. In addition, this review calls for stronger integration of measurement and modeling to better study BC sources, aging, and mixing states, and highlights the need for assessing source-specific health impacts and understanding how atmospheric aging modifies BC toxicity.