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161. 题目: Fabrication of Calcium-Loaded Biochar from Spent Coffee Grounds and Oyster Shells for Enhanced Phosphate Removal and Role of Site Energy Distribution
文章编号: N26050203
期刊: Journal of Environmental Chemical Engineering
作者: Xiaoyu Liu, Jiyue Ding, Yi Wang, Ke Cui, Qingyang Xu, Ning Zhang, Huachi Yu, Jingyi Chen, Qian Zhang, Pingke Yan, Zilin Meng
更新时间: 2026-05-02
摘要: Phosphorus is a vital nutrient for plant and animal growth, but its overabundance in water bodies causes eutrophication. In this study, spent coffee grounds and oyster shells were used as raw materials to prepare calcium-loaded biochar (OS@CGB) through a mechanochemical method combined with high-temperature calcination, and the resulting material was evaluated as an adsorbent for phosphate removal from water. Compared with pristine spent coffee ground biochar (CGB), the composite material prepared with oyster shell (OS) addition possessed more adsorption capacity, thereby providing a greater number of adsorption sites and a higher adsorption capacity. Adsorption kinetics followed a pseudo-second-order model, while the isothermal adsorption behavior was well described by the Generalized Langmuir model. Site energy distribution analysis suggested that the adsorption of phosphate first reacted with calcium oxide with high-energy sites, and then was fixed on the carbon matrix derived from waste coffee grounds. It is dominated by the precipitation reaction with calcium oxide, supplemented by the electrostatic interaction and surface complexation of the carbon matrix derived from waste coffee grounds. Coexisting cation and pH effect experiments further demonstrated that OS@CGB exhibited stable adsorption performance toward phosphate. Post-adsorption characterizations revealed that different calcium contents resulted in the formation of distinct phosphate precipitates. Moreover, phosphate release and plant growth experiments on the spent samples confirmed that OS@CGB exhibited a phosphate release capacity, and samples with higher release amounts promoted better plant growth. These findings suggest that OS@CGB is a promising, efficient, stable, and low-cost material for phosphate adsorption in environmental applications.

162. 题目: The broad-spectrum adsorption capability of ultrafine MgO biochar composites based on steam-exploded corn straw for the efficient removal of cationic heavy metals
文章编号: N26050202
期刊: Separation and Purification Technology
作者: Yanpeng Huang, Yuming Xu, Jingfan Yan, Fumin Chu, Siyu Jia, Dongmin Li, Sen Yang
更新时间: 2026-05-02
摘要: Cationic heavy metals are highly toxic and often coexist with large concentration gradients in wastewater, making their efficient removal particularly challenging. In this study, corn straw (CS) and steam-exploded corn straw (SCS) were employed as carrier materials to prepare MgO biochar composites (MgO/CS and MgO/SCS) via an impregnation-precipitation-pyrolysis method. After normalization based on MgO content, the adsorption capacity ratios of MgO/SCS to MgO/CS reached 1.95 for Pb²⁺, 1.37 for Cu²⁺ and 1.93 for Zn²⁺, clearly demonstrating the importance of carrier material. MgO/SCS exhibited excellent adsorption capacities for Pb²⁺ (1466 mg g⁻¹), Cu²⁺ (711 mg g⁻¹) and Zn²⁺ (635 mg g⁻¹), along with ultrafast adsorption kinetics (76.8% of the equilibrium adsorption capacity for Pb²⁺ can be achieved within 20 min) and strong tolerance toward acidic conditions and coexisting substances. Mechanistic analyses revealed that Pb²⁺ and Zn²⁺ adsorption was dominated by surface precipitation, whereas Cu²⁺ adsorption involved both precipitation and complexation. More importantly, 2 g L⁻¹ MgO/SCS can remove all cationic heavy metals from the electroplating, mining and smelting simulated wastewater, reducing residual heavy metal concentrations to levels far below the corresponding Chinese discharge standards. The superior performance and broad-spectrum adsorption capabilities of MgO/SCS, which are due to the localized alkaline microenvironments formed by ultrafine MgO nanoparticles, together with its cost-effectiveness, making it highly promising for industrial applications.

163. 题目: Mechanistic Insights into Humic Acid Degradation by Radical Synergy in an HOCl-Assisted Photocatalytic System
文章编号: N26050201
期刊: Journal of Environmental Chemical Engineering
作者: HwaYong Lee, HanBit Lee, JongHyeon Lee, HongSeok Choi, HwanHee Choi, YoungHee Kim
更新时间: 2026-05-02
摘要: Humic acid (HA), a major fraction of natural organic matter, is a key precursor of chlorinated disinfection by-products (DBPs) during drinking water treatment. In this study, a Hypochlorous acid (HOCl)-assisted TiO₂ photocatalytic system was developed to enhance HA degradation while suppressing trihalomethane (THM) formation. Under ultraviolet (UV) irradiation, the combined UV/HOCl/TiO₂ process exhibited substantially higher HA removal than UV/TiO₂ or UV/HOCl alone, achieving >93% removal at an HOCl concentration of 20 mg/L. Kinetic analysis revealed a transition from pseudo-first-order to pseudo-second-order behavior with increasing HOCl dosage, indicating a shift from oxidant-limited to radical-dominated reaction regimes. Probe-based experiments using p-Nitrosodimethylaniline (RNO) and tert-butanol (t-BuOH) quantitatively demonstrated that, under HOCl 10 mg/L UV/TiO₂ conditions, hydroxyl radicals (•OH) accounted for 73.4 ± 5.2% of HA oxidation, while chlorine-centered radicals (Cl•/Cl₂^•⁻) contributed 26.6 ± 5.2%. The combined system exhibited a synergy index of 1.92, confirming true non-additive radical interactions. The photocatalytic decomposition of HA was confirmed by FT-IR analysis, which revealed the preferential destruction of aromatic and chromophoric HA structures associated with DBP precursor reactivity. Notably, enhanced HA degradation was accompanied by THM concentrations remaining below 0.015 mg/L, demonstrating effective suppression of DBP formation. These results demonstrate that controlled radical synergy enables efficient HA removal while mitigating DBP risks in advanced water treatment.

164. 题目: Effect of 100-year-long-term crop rotation and organic fertilisation on top sandy soil layer properties and stability of soil organic matter
文章编号: N26050109
期刊: Agriculture, Ecosystems & Environment
作者: Edyta Hewelke, Aneta Perzanowska, Barbara Klik, Artur Pędziwiatr, Dariusz Gozdowski, Barbara Gworek, Łukasz Uzarowicz, Maja Radziemska, Wojciech Stępień
更新时间: 2026-05-01
摘要: An effect of a unique 100-year-long-term field experiment on sandy Luvisol soil processes, with different organic amendments applied, was used to determine key water and carbon soil resilience in the ploughing layer (0–20 cm), particularly in the context of soil functionality under changing environmental conditions. Four crop rotation systems were selected: control without organic fertilization (CON), with manure application (MAN), cultivation of legumes as one crop in a rotation system (LEG), and manure application and legume cultivation (MAN-LEG). The MAN-LEG significantly enhanced the soil's water retention capacity, increasing plant-available water by 6% (relative). In contrast, legume cultivation without manure resulted in a 2.5% rel. reduction in full water holding capacity. Soil water repellency remained low (Class 0–1), indicating favourable conditions for water infiltration and no adverse hydrophobic effects from organic matter inputs. Aggregate stability improved under organic fertilisation, particularly in the MAN-LEG system (7% rel.), as reflected by soil structure indicators. Labile organic carbon (POXC) increased markedly under organic treatments, with the highest values observed in MAN–LEG (approximately 2.5-fold compared to CON). Carbon indices, namely the Carbon Pool Index Index (CPI), Lability Index (LI), and the Carbon Management Index (CMI), consistently indicated improved carbon management status under organic amendments (CON

165. 题目: Substrate source and mineral protection synergistically govern the temperature response of lake sediment organic carbon
文章编号: N26050108
期刊: Geochimica et Cosmochimica Acta
作者: Beichen Wang, Xiaoxi Sun, Zhen Yang, Xinyi Li, Min Cai, Bingfu Yao, Li Liu, Tianran Sun, Jian Yang, Jibin Han, Xiying Zhang, Jianping Wang, Hongchen Jiang
更新时间: 2026-05-01
摘要: Lake sediments constitute a significant yet vulnerable component of the global carbon cycle. Nevertheless, the mechanisms controlling the temperature response of source-specific organic carbon (OC) remain unclear, limiting predictive capability of climate-carbon feedbacks. To address this, we investigated the decomposition of plant- and microbial-derived OC in Qinghai-Tibetan Plateau lake sediments via a 180-day microcosm incubation at 8 °C and 18 °C, integrating biomarker analysis, optical spectroscopy, and mass spectrometry. The results show that plant-derived OC forms the foundational component of the sediment OC pool, dominating total OC accumulation and exhibiting low temperature sensitivity, which facilitates its preservation under warming. In contrast, microbial-derived OC shows higher temperature sensitivity and is preferentially decomposed at elevated temperatures; its stability depends strongly on mineral protection, correlating positively with clay content, reactive calcium, and cation exchange capacity. We propose a synergistic framework wherein the substrate source establishes the baseline stability of sediment OC, while mineral protection modulates the temperature-sensitive microbial fraction. The overall OC response to warming is determined by the trade-off between these two mechanisms, implying a potentially diminishing climate-carbon feedback from lake ecosystems over time. This study provides a mechanistic basis for predicting OC fate in inland waters under warming.

166. 题目: Coupled Optical and Molecular Insights Into Dissolved Organic Matter Dynamics in Runoff From Patchy Slopes Co‐Covered by Vegetation and Biocrusts During Rainfall in Arid and Semiarid Regions
文章编号: N26050107
期刊: Land Degradation & Development
作者: Fei Wang, Guo Chen, Jianhang Lan, Lihong Jia, Qingwei Zhang, Fengbao Zhang, Jian Wang, Yu Pang, Ming Li, Ding He, Hao Wang
更新时间: 2026-05-01
摘要: Arid landscapes are shifting from biocrusts‐ or vascular plant‐dominated systems to mosaics where both coexist under climate change; yet, dissolved organic matter (DOM) dynamics in these transitional habitats remain poorly understood. Therefore, three types of runoff plots were set on slopes with biocrusts (BC), Bothriochloa ischaemum (L.) + biocrusts (BI BC ), and Artemisia sacrorum Ledeb. + biocrusts (AS BC ) in a typical semiarid region. The dynamics of DOM in surface runoff were analyzed by simulated rainfall experiments coupled with optical techniques and Fourier transform ion cyclotron resonance mass spectrometry (FT‐ICR MS). Overall, the DOM loss rates in the BI BC and AS BC were significantly reduced compared to the BC. Runoff from all runoff plots was dominated by the DOM with protein‐like components (34% to 96%). Runoff from the BC was characterized by a 1.48‐ to 2.08‐fold higher proportion of humic‐like components compared to BI BC and AS BC , accompanied by greater aromaticity and a higher degree of humification. DOM in runoff across all runoff plots was dominated by CHO compounds (52%), with highly unsaturated compounds as the primary constituents (52%). DOM in the runoff from the BC exhibited more stable molecular structures and stronger aromaticity, whereas those from the AS BC showed a higher proportion of multi‐heteroatomic components such as CHONP and CHONS. In conclusion, herbaceous vegetation and biocrusts form composite patches that regulate DOM transport and loss by modifying its quantity, composition, and stability. These processes have important implications for water quality and carbon cycling in arid landscapes. This study also highlights the synergistic value of integrating optical and molecular techniques to advance understanding of ecosystem‐scale DOM dynamics.

167. 题目: Microplastic-derived dissolved organic carbon affects soil organic carbon mineralization through shifts in microbial community composition
文章编号: N26050106
期刊: Soil Biology and Biochemistry
作者: Hongxin Dong, Shixiu Zhang, Yanmei Fu, Peng He, Biao Zhu, Lu-Jun Li
更新时间: 2026-05-01
摘要: Microplastics pollution constitutes a global environmental challenge. Although degradable microplastics can alter soil organic carbon (SOC) mineralization through the priming effect, the key drivers governing this process remain poorly understood, especially in the subsoil (>30 cm). Combining a meta-analysis, an incubation experiment, and a random forest model, we found that dissolved organic carbon (DOC) from microplastics decomposition affected the priming effect by regulating microbial growth. Specifically, the highly biodegradable polyhydroxyalkanoate promoted microbial growth by increasing the DOC released from microplastics decomposition, thereby enhancing SOC mineralization via a positive priming effect (462 to 1198 mg CO2–C kg−1 soil). Polylactic acid with low biodegradability reduced carbon availability through the sorptive protection of soil DOC, consequently decreasing SOC mineralization by 149 to 268 mg CO2–C kg−1 soil. In the subsoil, fungi primarily used the microplastics-derived DOC as carbon and energy source through enzyme-mediated nutrient mining, which represents the main driving mechanism for the strong positive priming effect. In the topsoil, the preferential absorption and assimilation of microplastics-derived DOC by bacteria promoted the microbial necromass accumulation, thus attenuating the priming effect through microbial and mineral carbon pumps. These findings highlight the role of carbon availability (particularly DOC) in topsoil and subsoil on the microplastics-induced priming effect, and underscore the necessity of incorporating soil carbon status into assessments of microplastics pollution impacts on global carbon budgets and soil health.

168. 题目: Waste control by waste: Preparation of functionalised lanthanum-modified magnetic red mud biochar for efficient phosphate adsorption in water bodies and environmental risk assessment
文章编号: N26050105
期刊: Separation and Purification Technology
作者: Yunrui Zhao, Bukai Song, Rubin Han, Bao-Jie He, Hui Luo, Zhaoqian Jing
更新时间: 2026-05-01
摘要: The current research is based on the preparation of novel lanthanum-modified magnetic biochar (La-MRBC) through the pyrolysis of industrial waste red mud (RM) and agricultural waste walnut shell (WS), followed by lanthanum modification, aimed at addressing the challenges of hazardous industrial waste disposal, water eutrophication, and the scarcity of phosphate resources. The synthesized La-MRBC demonstrated remarkable magnetic responsiveness (13.94 emu/g), while adsorption analysis revealed outstanding phosphate removal potential, with a maximum adsorption equal to 134.78 mg P/g, following pseudo-second-order kinetics and the Langmuir isotherm, suggesting a chemisorption-dominated monolayer adsorption. Mechanistic analysis demonstrated the involvement of inner-sphere complexation, precipitation, ligand exchange, and electrostatic attraction for achieving phosphate removal. La-MRBC significantly retained high adsorption efficiency under the influence of coexisting ions, while demonstrating remarkable recyclability with 18% efficiency loss after 5 cycles, and rapidly removing 99% of phosphate from actual domestic sewage within 15 min. The assessment of heavy metal leaching, along with their associated health risks, demonstrated negligible non-carcinogenic (HQ < 1) and carcinogenic risks (CR < 1E-6) to adults and children. This study presents a strategy for developing an environmentally friendly, high-performance magnetic adsorbent, introduces new approaches for hazardous industrial waste recycling, and demonstrates remarkable sustainability potential

169. 题目: Biochar and activated carbon catalytic thermal decomposition of polybrominated diphenyl ethers at low-temperature: Efficiency, mechanisms, and intermediate evolution tracking
文章编号: N26050104
期刊: Journal of Environmental Chemical Engineering
作者: Meihui Wen, Xiaodong Du, Peiwen Wu, Jiahao Liang, He Liu, Wenwei Lyu, Waseem Hayat, Xueqin Tao, Zhi Dang, Guining Lu
更新时间: 2026-05-01
摘要: Biochar (BC) and activated carbon (AC) are widely used adsorbents for polybrominated diphenyl ethers (PBDEs). However, regeneration of PBDE-loaded carbon adsorbents typically requires high temperatures, resulting in high energy consumption and potential formation of brominated dioxins. Developing low-temperature decomposition strategies for PBDEs during carbon regeneration is therefore important. This study found that catalytic thermal decomposition of PBDEs over BC and AC achieved efficient decomposition at low temperatures (150–300 °C), with inhibition of dioxin formation. All seven carbon materials enhanced BDE-47 degradation at 300 °C. Corn stalk BC exhibited the highest activity, achieving 98.20% degradation within 60 min and a 37-fold rate increase. Arrhenius analysis indicated BC increased the frequency factor, suggesting enhanced reaction probability. Structural characterization showed that the mesoporous structure of BC provides accessible reaction interfaces, while oxygen-containing functional groups facilitate radical formation. Product analysis revealed that these radicals likely alter reaction pathways, suppressing toxic higher-brominated dibenzofurans and reducing overall product toxicity. BC also enhanced decomposition of tri‑ to hepta‑brominated congeners, confirming the radical‑mediated mechanism and its broad applicability. These findings provide mechanistic insights into carbon-catalyzed low-temperature PBDEs decomposition, which is relevant to the treatment of PBDE-contaminated carbon materials and the control of PBDEs emissions during e-waste thermal treatment.

170. 题目: Radical-driven peroxydisulfate activation by Fe–Mn bimetallic N-doped biochar for fluoxetine defluorination and degradation: Mechanistic insights and toxicity evolution
文章编号: N26050103
期刊: Journal of Environmental Chemical Engineering
作者: Yuankun Liu, Yuanqi Cao, Gangyi Sun, Zhiwei Zhou, Xing Li, Zhonglin Chen
更新时间: 2026-05-01
摘要: Fluoxetine (FLX), a widely used antidepressant, has been increasingly detected in aquatic environments due to its high chemical stability and resistance to biodegradation, posing potential ecological risks. In this study, sludge was used as a precursor to synthesize a Fe–Mn bimetallic nitrogen-doped biochar (FeMn/NBC), enabling the resource utilization of solid waste, which was further applied for peroxydisulfate (PDS) activation to achieve efficient degradation and defluorination of FLX. The superior catalytic performance originated from the synergistic coupling between the N-doped carbon framework and Fe–Mn bimetallic active sites. Nitrogen doping enhanced adsorption and PDS activation, while the bimetallic configuration further improved radical generation efficiency, electron transfer, and catalyst stability. Under optimal conditions (FLX = 10 mg/L, PDS = 2 mM, FeMn/NBC-4 = 0.4 g/L), complete removal of FLX was achieved within 60 min. The system exhibited stable performance over a wide pH range, in the presence of coexisting anions, and in real water matrices, with low metal leaching. Quenching experiments indicated that SO₄•⁻ and •OH were the dominant reactive species. The redox cycling of Fe(II)/Fe(III) and Mn(II)/Mn(III) facilitated continuous PDS activation, while the nitrogen-doped carbon framework enhanced electron transfer. DFT calculations combined with LC–MS analysis revealed that SO₄•⁻ first oxidized FLX via electron transfer, followed by •OH weakening the stability of the C–F bond through electrophilic addition and inducing its cleavage. Toxicity evaluation indicated that the degradation intermediates exhibited reduced ecological risk. These findings provide new insights into the degradation and defluorination mechanisms of fluorinated pharmaceuticals.

171. 题目: Role of dissolved black carbon in facilitating sulfonamide antibiotics transformation by fungal laccase: Enzymatic kinetics, degradation mechanisms, and phytotoxicity evaluation
文章编号: N26050102
期刊: Journal of Environmental Chemical Engineering
作者: Gang Chu, Kexin Chang, Xinyue Hu, Zhihong Li, Shakeel Ahmad, Hongbo Peng, Jing Zhao, Bo Pan, Patryk Oleszczuk
更新时间: 2026-05-01
摘要: While biochar has garnered significant attentions for its potential in sustainable agriculture, however, the role of biochar-derived dissolved black carbon (DBC) in mediating enzymatic degradation of sulfonamide antibiotics by extracellular laccase (LA) remains poorly understood. Therefore, we systematically investigated the role of DBC on sulfonamide degradation driven by fungal LA. Combined with radical capture and fluorescence analysis, DBC-mediated reaction kinetics of sulfamethoxazole (SMX) and sulfamerazine (SMR) by LA were explored in oxygen-rich condition. Results showed that increasing DBC concentrations enhanced LA-driven catalytic oxidation of sulfonamides, accompanied by the conversion of phenolic moieties in DBC to generate semiquinone radicals and singlet oxygen (1O2) via single-electron-transfer pathway. The reactivity of semiquinone radicals in DBC was assessed to SMX and SMR degradation for the first time in LA-inactivation system, while LA-induced 1O2 generation contributed significantly to S–N bond cleavage of both sulfonamides in enzymatic reaction. The phytotoxicity experiment demonstrated that the root and stem lengths of pea seedlings were distinctly enhanced in the presence of DBC after LA application. The detoxified products including co-polymers through enzymatic degradation facilitated pea seedling cultivation. These results indicated DBC intervention contributed effectively to the detoxification of sulfonamides driven by fungal LA, and circumvented the ecological risks of antibiotics in farmland ecosystem. This work will provide an insight into the dual role of DBC in promoting exoenzyme-driven antibiotic degradation and boosting sustainable agriculture production.

172. 题目: Stable carbon isotopic tracing of organic matter transformation and soil CO2 sources across tropical sub-humid to semi-arid climates
文章编号: N26050101
期刊: Organic Geochemistry
作者: Amzad Hussain Laskar, Ranjan Kumar Mohanty, Rahul Kumar Agrawal, Ankur Kumar Dabhi, Sanjeev Kumar
更新时间: 2026-05-01
摘要: Soil organic carbon (SOC), one of the largest terrestrial carbon reservoirs, is formed as photosynthetically fixed CO2 is incorporated into soils via microbial decomposition. Stable carbon isotope ratio (δ13C) is an effective tracer of SOC transformation. This study investigates δ13C variations in plant materials, SOC and soil-respired CO2 (soil CO2) from agricultural and forest soils across semi-arid to sub-humid regions of Gujarat, western India. The analysis aims to quantify isotopic fractionation during litter and SOC decomposition at different stages of development and to assess how land-use practices influence soil carbon sequestration. Fractionation factors (ε) were calculated for the conversion of plant materials to SOC, and contributions of different organic matter pools to soil CO2 were quantified using an isotopic mixing model. The estimated ε ranged from −0.58 ‰ to −3.48 ‰, with no clear dependence on vegetation, land use or climate. Transformation from plant matter to surface SOC caused 93–99% carbon loss, with 13C enrichment of 10.30 ± 3.44, 7.18 ± 2.61, and 5.95 ± 3.59 ‰ in agricultural, dry deciduous and wet deciduous forests, respectively. Soil CO2 δ13C indicated mixing, with ∼76% from root respiration, ∼19% from fresh SOC, and ∼5% from older SOC. SOC δ13C reflects pre-agricultural C3 vegetation, despite current C4 cropping in an agricultural site, indicating minimal carbon sequestration in agricultural soils. Distinct δ13C signatures from different pools, arising during plant-to-SOC conversion and further decomposition enable quantitative estimation of contributions to the soil CO2 from various carbon pools. δ13C-based partitioning reveals limited sequestration under current land use practices in semi-arid tropics.

173. 题目: Particulate organic carbon exhibits greater vulnerability to short-term elevated CO2 than mineral-associated organic carbon in a cropland soil
文章编号: N26043008
期刊: Agriculture, Ecosystems & Environment
作者: Xiurui BAO, Xinyue ZHANG, Xue HAN, Hui JU
更新时间: 2026-04-30
摘要: The effects of elevated CO2 on particulate organic carbon (POM-C) and mineral-associated organic carbon (MAOM-C) remain unclear, as conflicting results arise from differences in CO2 enrichment levels and sampling times. Besides, the extent to which microbial processes mediate these pools under elevated CO2 remains largely unresolved. This study is based on a free-air CO2 enrichment (FACE) platform in a winter wheat field in North China, with two elevated CO2 treatments (+100 and +200 µmol/mol) and sampling across crop growth stages. It aims to elucidate the dynamics of POM-C and MAOM-C under elevated CO2 and their underlying microbial-driven mechanisms. Results showed that short-term exposure to + 200 µmol/mol CO2 significantly reduced POM-C by 13.8% while MAOM-C remained unchanged, indicating that POM-C is more vulnerable to elevated CO2 than MAOM-C. The divergent responses of POM-C and MAOM-C to elevated CO2 disrupted the negative correlation previously observed between these two carbon fractions. Our results demonstrate that microbial necromass C is responsible for as much as 49.4% of POM-C in croplands, a proportion substantially higher than the 30.1% observed in MAOM-C. Importantly, elevated CO2 enhanced the contribution of microbial necromass C to POM-C mainly at the filling stage, highlighting that this effect is stage-dependent rather than a general response throughout the season. These findings underscore the importance of distinguishing between the two SOC fractions and accounting for temporal variation when evaluating soil C responses under rising CO2.

174. 题目: Intercropping enhances soil aggregate stability and associated organic carbon via divergent microbial assembly and co-occurrence networks
文章编号: N26043007
期刊: Agriculture, Ecosystems & Environment
作者: Yazhen Chen, Wenqiong Jiang, Yuanying Peng, Yichen Xu, Haobo Xu, Juan Chen, Xiaozhou Huang, Jinsong He, Xiaohong Wu, Jun Wang, Jianbo Jia, Wende Yan
更新时间: 2026-04-30
摘要: Intercropping is widely promoted for sustainable agroecosystems, but its effects on soil aggregate stability, aggregate-associated soil organic carbon (SOC) and the underlying microbial mechanisms remain unclear in Camellia oleifera plantations. This study investigated the impact of intercropping with legume (Trifolium repens, CT) or grass (Lolium perenne, CL) on soil aggregates and microbial communities across two phenological stages. Compared with monoculture (CK), CT and CL markedly increased the mass proportion of large macroaggregate (> 2 mm) by 33.48% and 17.11% during the growing stage, with attenuated increments during the wilting stage. Correspondingly, soil aggregate stability (geometric mean diameter, GMD) was improved by 60.22% and 48.66% in the growing stage, and 25.60% and 19.36% in the wilting stage, respectively. CT persistently increased SOC in large macroaggregate by 27.93%–36.45%, which was higher than that in CL (22.44%–26.44%). High-throughput sequencing revealed that intercropping enhanced bacterial and fungal richness by 27.5%–52.4% and 101.0%–126.6% (p < 0.05), particularly during the wilting stage. Concurrently, intercropping strengthened microbial network complexity and stability, especially for fungi, as evidenced by higher average clustering coefficients (176.51%–386.04%) and negative-to-positive cohesion ratios (5.66%–23.48%). Intercropping shifted bacterial assembly toward stochastic processes while fungal assembly became more deterministic. Pathway modeling demonstrated that assembly-induced shifts in microbial diversity and interactions enhanced aggregate-mediated SOC protection in intercropping systems (GoF = 0.6857), with fungal community contributing more than bacterial community. These findings indicate that legume intercropping better improves soil structure and aggregate-associated SOC by reshaping microbial assembly patterns and enhancing network stability. Notably, appropriate management during the wilting stage is critical for optimizing microbial-mediated aggregate stability and SOC retention in C. oleifera agroecosystems, particularly under legume intercropping.

175. 题目: Atmospheric oxygen constraints on Southern Ocean productivity and drivers of carbon uptake
文章编号: N26043006
期刊: Nature Geoscience
作者: Yuming Jin, Britton B Stephens, Matthew C Long, Manfredi Manizza, Nicole S Lovenduski, Cynthia Nevison, Eric J Morgan, Ralph F Keeling
更新时间: 2026-04-30
摘要: Ocean net primary production fixes dissolved carbon into organic matter while producing O2, driving the biological carbon pump that contributes to ocean CO2 uptake. The Southern Ocean plays a critical role in carbon export, yet its productivity estimates remain highly uncertain due to limited observations. Here we constrain Southern Ocean (south of ~44° S) net primary production by linking Coupled Model Intercomparison Project Phase 6 (CMIP6)-modelled productivity to modelled air–sea O2 fluxes and applying O2 flux estimates derived from airborne O2/N2 observations. We find an annual net primary production of 6.5 ± 1.36 PgC yr−1, substantially higher than most CMIP6 model and satellite-based estimates, but consistent with Argo oxygen-based estimates. We show that CMIP6 models with underestimated productivity exhibit weak summer CO2 uptake, with some also showing excessive summer temperature-driven outgassing. Together, these models produce incorrect seasonal CO2 flux cycles with summer outgassing, whereas observation-based estimates indicate summer uptake. These errors may stem from inadequate model representation of ocean vertical mixing, which affects nutrient supply, stratification and heat redistribution. Our productivity estimates provide quantitative benchmarks that, combined with constraints from airborne CO2 observations and surface ocean pCO2 and temperature observations, reduce uncertainty in estimates of model-projected end-of-century Southern Ocean CO2 uptake by 53%.

176. 题目: Freezing-Enhanced Accumulation of ROS Generated by Fulvic Acid: Implications for As(III) Oxidation.
文章编号: N26043005
期刊: Environmental Science & Technology
作者: Wenxiu Qin, Wenwen Li, Jiamin Yang, Jinsong Liu, Guodong Fang, Youbin Si, Dongmei Zhou
更新时间: 2026-04-30
摘要: Humic substances (HS), as redox-active organic macromolecules, are capable of generating reactive oxygen species (ROS) through redox-active moieties such as quinones and phenolic groups. Despite extensive research having elucidated these redox processes in aqueous systems, there is a paucity of knowledge regarding the electron transfer pathways of these processes under freezing conditions, a common environmental scenario in temperate, polar, and high-altitude regions. Here, we demonstrated a previously unrecognized and environmentally significant pathway: freezing dramatically enhanced fulvic acid (FA)-mediated oxidation of As(III) in ice (from -5 to -18 °C), achieving 68% conversion within 96 h at -18 °C compared to negligible transformation in aqueous phases (4-25 °C). Mechanistic investigations revealed that this cryogenic acceleration was ascribed to a synergistic freeze-concentration effect and a kinetic decoupling of ROS generation from scavenging. In situ fluorescence imaging directly visualized ROS accumulation within ice grain boundaries, while complementary spectroscopic (EPR and 3D-EEM) and chromatographic (GPC) analyses revealed that freezing suppressed FA humification, thereby redirecting ROS from self-consumption toward As(III) oxidation. H2O2 and O2•- served as the dominant oxidants. These findings redefine our understanding of arsenic redox cycling in cold environments, highlighting cryogenic conditions as a critical period for geochemical and pollutant redox dynamics in the environment containing HS.

177. 题目: Long-term vegetation restoration enhances soil carbon sequestration along a 170-year chronosequence.
文章编号: N26043004
期刊: Journal of Environmental Management
作者: Ziyuan Liu, Jiwei Li, Jinyuan Yu, Zhenhao Wei, Shu Zhu, Zhouping Shangguan, Lei Deng
更新时间: 2026-04-30
摘要: Long-term agricultural cultivation accelerates soil erosion and exacerbates water and soil organic matter loss. Vegetation restoration is widely recognized as an effective strategy for improving soil carbon (C) sequestration. However, the effects of vegetation restoration following farmland abandonment on soil organic carbon stock (SOCS) and its fractions across soil profiles remain poorly understood. Here, we investigated the dynamics of SOCS, particulate organic carbon stock (POCS), mineral-associated organic carbon stock (MOCS) and their driving factors across a 0-100 cm soil profile over a 170-year chronosequence following farmland abandonment on the Loess Plateau of China. The results showed that 170 years of vegetation restoration increased SOCS and POCS by 41.5% and 81.2%, respectively. In the 20-100 cm layer, SOCS and POCS initially declined and began to increase after approximately 30 years of vegetation restoration. MOCS remained unchanged in the 0-60 cm layer, whereas increased in the 60-100 cm layer after vegetation restoration. The 40-60 cm layer served as a transitional zone, marking a shift in dominant sequestration mechanisms from POCS-dominated accumulation in the topsoil (0-40 cm) to MOCS-dominated stabilization in the subsoil (60-100 cm). SOCS and POCS were driven by plant-derived inputs, while MOCS was mainly controlled by soil physical properties and microbial activity. Our findings demonstrate that long-term vegetation restoration effectively enhances soil organic carbon and particulate organic carbon accumulation in surface soils while promoting the stabilization of mineral-associated organic carbon in subsoil, highlighting the importance of vegetation restoration for sustainable soil C management.

178. 题目: Impact of fire frequency and elevation on soil carbon fractions, nitrogen dynamics and physicochemical properties in Himalayan Chir Pine forests.
文章编号: N26043003
期刊: Journal of Environmental Management
作者: Jyoti Devi, D R Bhardwaj, Saurbh Shukla
更新时间: 2026-04-30
摘要: Given the rising vulnerability of forest carbon sinks to climate-intensified disturbances, this study evaluates how varying fire frequencies viz. High (HFZ), medium (MFZ) low (LFZ) and negligible fire zone (NFZ), and elevation gradients viz. Lower Shiwalik Chir pine forest (E1) and upper Himalayan Chir pine forest (E2) shape soil organic carbon fractions, nitrogen pools and physicochemical properties. Soil carbon fractions varied significantly with fire frequency, where very labile carbon (VLC) increased as fire frequency decreased and non-labile carbon (NLC) dominated high fire zones. Labile carbon in the NFZ and recalcitrant carbon in the HFZ significantly exceeded over other fire zones. LFZ exhibited higher carbon management index (CMI) and lability index (LI), whereas HFZ showed higher carbon pool index (CPI) and recalcitrance, underscoring the influence of fire regimes and elevation on soil carbon dynamics and forest productivity. Total nitrogen, ammoniacal nitrogen and nitrate nitrogen were significantly higher in upper Himalayan Chir pine forest ecosystems than in Shiwalik Chir pine forests, with the highest nitrogen concentrations generally recorded in mid-frequency fire zones (MFZ). Upper Himalayan Chir pine forests and low fire-frequency zones exhibited superior soil quality, characterized by higher nutrient concentrations (N, P, K, Mn) and organic carbon alongside lower bulk density, while fire-affected zones showed increased pH, K and electrical conductivity. These findings highlight that while frequent fires can promote carbon stabilization through recalcitrant carbon fractions, low-to-negligible fire regimes are essential for enhancing the lability index, soil fertility, active carbon pools and overall ecosystem productivity in Himalayan Chir pine forests.

179. 题目: Fertiliser use and carbon sequestration in agricultural soils
文章编号: N26043002
期刊: Agriculture, Ecosystems & Environment
作者: Nanthi Bolan, Xiaofei Lv, Yue Xu, Tilak Mondal, Shiv Bolan, Pete Smith, Grant A Campbell, Santanu Mukherjee, Grace Kelbel, Sreeni Chadalavada, Kadambot H M Siddique
更新时间: 2026-04-30
摘要: Current initiatives to sequester carbon (C) in soils as a strategy to mitigate climate change are gaining momentum in many countries. While agriculture makes a significant contribution to greenhouse gas (GHG) emissions, it also plays a critical role in regulating global soil C pools, as almost 40% of the global soils are used for food and fibre production. Fertiliser manufacture and use in agriculture is a major contributor to GHG emissions. Agricultural management practices including tillage, pest and disease control, fertiliser input and irrigation impact soil C stocks and C sequestration potential, so improving agricultural soil management practices can help in mitigating climate change. This review provides a bibliometric analysis and critical discussion on the impacts of fertiliser use on soil C sequestration through increased C inputs resulting from greater biomass production, and formation of soil organic matter (SOM). Depending on the fertility status of the soil, fertiliser use can lead to either an increase or a decrease in soil C storage. In both low and high fertility soils, fertiliser use can promote soil C stocks by enhancing the amount of C inputs (e.g., crop residues) resulting from higher biomass yields, and improving stoichiometric relations of crop residues restored to the soil, thereby accelerating the rate of formation of SOM. In high fertility soils, fertiliser input can also accelerate the rate of decomposition of SOM, thereby impacting net C storage in the soil in relation to increased biomass yield. Fertiliser management practices, yields and soil conditions vary across regions, highlighting that recommendations on fertiliser use in relation to climate change mitigation strategies need to account for these differences.

180. 题目: The role of Ce in humic acid retention by Fe minerals as a function of Ce concentration, pH, and redox conditions: Implications for soil organic carbon stabilisation
文章编号: N26043001
期刊: Chemical Geology
作者: Jie Yu, Jiang Yu, Pengxinyue Huang, Zhi Huang, Siwei Deng, Wei Li, Ian T Burke, Caroline L Peacock
更新时间: 2026-04-30
摘要: Soil organic carbon (SOC) stabilisation by Fe minerals is a major pathway for terrestrial carbon storage, yet redox fluctuations drive Fe mineral transformations that alter mineral–organic interactions. Cerium (Ce) is a highly redox-sensitive rare earth element and often adsorbs onto reactive Fe phases. Whether Ce adsorption influences Fe redox cycling and organic carbon retention in Fe–organic matter associations remains unclear. Here we investigate the effects of Ce, applied at environmentally relevant soil-solution concentrations, on dissolved organic carbon (DOC) release from ferrihydrite– and hematite–humic acid organo-minerals under controlled pH and redox conditions. Batch experiments show that Ce adsorption reduces DOC release across all tested conditions, with maximum decreases of 76 ± 3% in ferrihydrite–humic acid and 73 ± 1% in hematite–humic acid organo-minerals. Spectroscopic and microscopic analyses indicate that Ce-mediated DOC retention follows distinct mechanisms in different organo-mineral systems, supported by density functional theory calculations. For ferrihydrite–humic acid, Ce predominantly forms inner-sphere complexes on ferrihydrite surfaces, with spectroscopic and DFT results consistent with interfacial CeFe redox interactions. Under acidic or fluctuating redox conditions, this may help preserve mineral–organic associations by limiting ferrihydrite dissolution and DOC release. In contrast, for hematite–humic acid, Ce adsorption is dominated by ligand complexation with humic acid, while under alkaline conditions Ce-bearing nanoparticles may further enhance mineral–organic cohesion and reduce DOC release. These findings show that Ce enhances organic carbon retention through mineral-specific pathways in controlled Fe– organic matter model systems, with potential implications for SOC stabilisation in Fe-rich soils.