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1. 题目: Nonlinear responses of soil organic carbon to biochar application rates in rice paddies: a data synthesis and future challenges
文章编号: N26101918
期刊: Journal of Soils and Sediments
作者: Husna Israt Pia, Nuri Baek, Seo-Woo Park, Eun-Seo Shin, Tae-Yeon Lee, Hyun-Jin Park, Jin-Hyeob Kwak, Han-Yong Kim, Tong Li, Yanjiang Cai, Woo-Jung Choi
更新时间: 2026-10-19
摘要: Purpose Data synthesis examining soil organic carbon (SOC) responses to increasing biochar (BC) application rates remains limited. This study investigated the linearity of SOC increases across various BC application rates using complied literature data. Methods Datasets were compiled covering BC application rates of 2.25–60 t ha⁻¹, with different feedstock types and pyrolysis temperatures (200–600 °C). The SOC gains (Cindex) resulting from BC application relative to the control and the Cindex increment per ton of BC applied (Unit Cindex) were computed. The linearity of the response of SOC to BC application rates was assessed via regression analyses. Cindex variations across BC application rates and pyrolysis temperature were assessed using Response Surface Methodology (RSM) modeling. Results BC increased SOC content (Cindex: 33.7%) and stock (24.9%) relative to the control; however, this increment exhibited a nonlinear response to application rates. Specifically, the Unit Cindex decreased as application rates increased, suggesting that the capacity of a unit mass of BC to enhance SOC diminishes at higher application rates due to SOC (including BC-derived C) loss. Furthermore, SOC in BC-amended soils decreased by up to 36% during rice growth season compared to the initial levels. The RSM modeling indicated that optimal BC application rates vary with pyrolysis temperature. Conclusion To accurately assess the SOC sequestration potential of BC, it is essential to integrate the SOC loss mechanisms into soil management strategies. Our findings provide a baseline for developing efficient BC management practices that maximize C persistence in paddy environments.

2. 题目: Submicroscale and Molecular Insights into Labile Organic Matter Transformation and Sequestration at Newly Formed Iron Minerals–Water Interfaces during O2-Mediated Fe(II) Oxidation
文章编号: N26101917
期刊: Environmental Science & Technology
作者: Li Li, Hanyue Zhang, Shiwen Hu, Yan Du, Xiaohui Xue
更新时间: 2026-10-19
摘要: Abiotic Fe(II) oxidation and subsequent precipitation are key pathways for controlling labile organic matter (OM) dynamics in O2-perturbed subsurface environments, yet the underlying coupling mechanisms remain poorly understood. Herein, OM transformation and sequestration during O2-mediated heterogeneous Fe(II) oxidation were evaluated at neutral pH across various C/Fe ratios. Increasing C/Fe ratios impeded Fe(II) oxidation but enhanced the level of reactive oxygen species (ROS) generation. Despite efficient sequestration, the OM immobilization efficiency varied with C/Fe ratios, with a minor fraction of OM being oxidized by ROS. Higher C/Fe ratios promoted ferrihydrite formation but inhibited its transformation into lepidocrocite, forming mineral-organic composites constituted by Fe–O cores and edge-/corner-sharing Fe–Fe shells. A direct visualization at submicroscale revealed heterogeneous spatial distributions of different organo functional groups on newly formed Fe mineral surfaces, reflecting OM selective immobilization. Newly formed Fe minerals preferentially immobilized high-molecular-weight compounds and those with more oxygenated or highly unsaturated structures, with stronger molecular fractionation at higher C/Fe ratios. Molecular-level analysis revealed that a lower C/Fe ratio promoted the conversion of phenols to quinones, aromatic ring opening, and carboxylation of aromatic substituents but inhibited polymerization of phenolic substances. Collectively, these findings deepen our knowledge of heterogeneous Fe mineral formation coupled with OM sequestration and transformation, advancing our understanding of Fe and C geochemical cycling in oxic soils and sediments.

3. 题目: Agglomeration-Induced Deactivation of Metal Oxide-Based Catalysts by Dissolved Organic Matter in Heterogeneous Fenton Systems
文章编号: N26101916
期刊: ACS ES&T Engineering
作者: Qiaoxin Li, Yehua Chen, Wenxiao Zheng, Jianyu Pan, Xin Luo, Tsung-Yi Chen, Zhi Dang, Chunhua Feng
更新时间: 2026-10-19
摘要: Heterogeneous Fenton processes are promising for wastewater treatment, yet their performance often deteriorates in dissolved organic matter (DOM)-rich waters. DOM inhibition has conventionally been attributed to reactive-species scavenging and active-site coverage. Here, we identify DOM-induced catalyst agglomeration as an additional deactivation pathway in metal oxide-based heterogeneous Fenton systems. DOM adsorbs onto catalyst surfaces through complexation, alters surface charge, and weakens interparticle electrostatic repulsion, thereby promoting rapid agglomeration and reducing the accessible catalytic surface area. At 30 mgC L–1 DOM, pH 4.0, and 25 °C, the hydrodynamic diameter of ferrihydrite increased from ∼220 nm to over 1300 nm, accompanied by a decrease in specific surface area from 118.1 to 62.8 m2 g–1. Similar DOM-induced inhibition was observed across six metal oxide catalysts, different DOM types, and real water matrices. Immobilizing ferrihydrite on a porous carbon substrate effectively suppressed particle migration and agglomeration, which enabled stable catalytic performance for over 30 h during continuous-flow treatment of landfill leachate. These findings extend the conventional understanding of DOM inhibition from chemical interference to catalyst-state destabilization and highlight particle stability as an important criterion for designing heterogeneous Fenton catalysts for practical water treatment.

4. 题目: Selective Destabilization of Mineral-Protected Organic Carbon Accompanies Iron Reduction across a Coastal Wetland Salinity Gradient
文章编号: N26101915
期刊: Environmental Science & Technology
作者: Xiaojin Hu, Jingyuan Yue, Zhen Hu, Huijun Xie, Jian Zhang, Kai Xue
更新时间: 2026-10-19
摘要: Climate-driven seawater intrusion is intensifying salinization in coastal wetlands, but its consequences for the stability of sediment organic carbon (OC) remain poorly constrained. Here, we combined field observations along a natural salinity gradient with spectroscopic and mineralogical analyses, mineral sorption–desorption experiments, and manipulative incubations to examine the stability of mineral-protected OC. Salt-marsh sediments contained 9.23% less OC than freshwater sediments, with a disproportionate difference in reactive iron-bound OC (FeR-OC). Across the 36 independent field plots, FeR-OC represented 9.80–22.95% of total OC, while the FW–SM FeR-OC difference was numerically equivalent to 64.28% of the corresponding bulk-OC difference. This disproportionate response was associated with a shift from reactive Fe(III)-bearing phases toward Fe(II)-rich products, as well as a weakening of mineral protection, supported by spectroscopic, mineralogical, and geochemical evidence. In salt-marsh incubations, molybdate addition decreased FeR-OC mobilization by 39.51%, identifying a molybdate-sensitive contribution consistent with the sulfate-reduction branch. Together, these results support an iron-unlocking pathway in sulfate-rich coastal wetlands, in which Fe reduction weakens mineral protection and mobilizes previously stabilized OC. This mechanism identifies iron-mediated mineral protection as an important geochemical vulnerability of blue carbon under increasing seawater influence, while the subsequent mineralization, export, or recapture of mobilized OC remains unresolved.

5. 题目: Remobilization risk of Cd in aged pig manure biochar under rice rhizosphere influence: Evidence from six-season cultivation
文章编号: N26101914
期刊: Journal of Environmental Management
作者: Xiao-qing Zhang, Fei-mei Chen, Ze-ning Yu, Rong-liang Qiu, Xin-xian Long
更新时间: 2026-10-19
摘要: Biochar is widely used to immobilize cadmium (Cd) in contaminated paddy soils; however, the long-term stability of biochar-adsorbed Cd under rice rhizosphere influence remains poorly understood, raising concerns about its potential secondary release. Herein, we investigated the remobilization behavior and speciation evolution of Cd from Cd-loaded pig manure biochar (Cd-PMB) using a six-season rice pot experiment, combined with a sequential simulated aging procedure designed to decouple the contributions of soil solution chemistry, root exudates, and oxidative processes. Two rice cultivars with contrasting Cd accumulation capacities were employed. Total Cd in Cd-PMB decreased by 84.3%–89.2% after six seasons, with >50% of the loss occurring during the first season, driven predominantly by cation exchange and rhizosphere acidification. Speciation analysis revealed that the ion-exchangeable Cd fraction was almost completely released (>95%) irrespective of planting treatment, while physically adsorbed and hydrogen-bonded Cd were preferentially remobilized under rhizosphere influence. Notably, complexed Cd exhibited a dual-phase dynamic, which initially increased by 8.1%–19.3% through secondary complexation onto newly formed carboxyl sites and subsequently declined during prolonged aging as these sites underwent protonation and oxidative degradation, as confirmed by Fourier‐transform infrared and X‐ray photoelectron spectroscopy analyses and further supported by significant Pearson correlations between COOH/ C O 3 2 − and Qcom-Cd (r = 0.801, p < 0.05). The simulated aging experiments confirmed that soil solution, root exudates, and oxidative aging synergistically promote Cd release from distinct binding pools. Our findings demonstrate that biochar-adsorbed Cd undergoes substantial, binding form–dependent remobilization during aging, posing a secondary risk that necessitates explicit consideration in long-term safety assessments of biochar-amended soils.

6. 题目: Trace Amines Scavenge Terpenoid-Derived Criegee Intermediates at Air–Liquid Interfaces to Form Atmospheric Organic Nitrogen
文章编号: N26101913
期刊: Environmental Science & Technology Letters
作者: Xiangyu Zhang, Yuya Tamura, Eiji Tamayose, Junting Qiu, Shinichi Enami, Kenichi Tonokura, Xinming Wang
更新时间: 2026-10-19
摘要: Organic nitrogen (ON) represents a chemically diverse fraction of atmospheric aerosols that profoundly modulates particle aging, toxicity, and light absorption. However, the exact kinetic pathways and timing of interfacial ON formation remain poorly constrained. Utilizing surface-sensitive mass spectrometry, we experimentally demonstrate that ambient, trace-level amines (5–40 ppt) can efficiently scavenge terpenoid-derived stabilized Criegee intermediates (SCIs) at the air–liquid boundary, successfully outcompeting interfacial hydration. Crucially, we elucidate a complete kinetic hierarchy for ON evolution across three sequential generations: SCIs, α-hydroxyalkyl-hydroperoxides (α-HH), and functionalized aldehydes all react with amines to converge on identical ON products. The reaction rates follow the strict order of SCI > α-HH > functionalized aldehyde, bypassing conventional bulk-phase carbonyl condensation via rapid nucleophilic attack and spontaneous H2O2 elimination. Rather than predicting global yields, our data explicitly identify a rapid, nonphotolytic entry point for ON formation that current condensed-phase schemes miss. Incorporating this bounded SCI–amine pathway into future multiphase mechanisms will significantly improve parametrizations of aerosol nitrogen chemical aging and ON-linked light absorption.

7. 题目: Iron-modified Calcinated Coconut Fiber Biochar for Simultaneous Removal of Copper and Zinc: Optimization, Production Cost Assessment, and Machine Learning Modeling
文章编号: N26101912
期刊: Water, Air, & Soil Pollution
作者: Xuan Thanh Bui, Thuy Trang Khuat, Phacharapol Induvesa, Nguyen Thuy Chung
更新时间: 2026-10-19
摘要: This study developed and evaluated an iron modified biochar (AcBC) from coconut fiber in Ben Tre, Vietnam, for the adsorption of Cu2⁺ and Zn2⁺. Characterization (SEM–EDS, BET, XRD, FTIR) showed that mineral rich coconut fiber pyrolyzed without inert gas undergoes strong surface mineralization, forming crystalline silicates that block pores and functional groups, resulting in raw biochar (RBC) with low surface area, limited porosity, and few active sites. After iron salt co precipitation with NaOH, AcBC exhibited major improvements, including a nearly 20- fold increase in surface area form 5 to 100 m2/g, well developed mesopores, and the return of functional groups. Silicate minerals also contributed to adsorption by providing active sites and supporting iron oxide and iron silicate formation. AcBC achieved about twenty percent higher removal efficiency and maximum capacities of 34.75 mg/g for Cu2⁺ and 29.69 mg/g for Zn2⁺, more than double those of RBC. To systematically describe the adsorption mechanisms, four kinetic models (pseudo-first-order, pseudo-second-order, Weber-Morris intraparticle diffusion, and Boyd) and four isotherm models (Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich) were utilized. Crucially, tree-based machine learning interpreted via SHAP analysis successfully quantified the mechanisms; Extreme Gradient Boosting accurately predicted adsorption capacity R2 > 92%, identifying specific surface area, % Si, and % O as the most important material properties, while that of cation descriptors relative atomic mass, effective ionic radius and first order hydrolysis constants. With low cost production, simple synthesis, and strong performance, AcBC represents a practical and scalable option for treating heavy metal contaminated wastewater in developing regions.

8. 题目: Decadal Biochar Legacy Stabilizes Paddy Soil Carbon by Reshaping Redox-Driven Reactive Oxygen Species Dynamics
文章编号: N26101911
期刊: Environmental Science & Technology
作者: Wendan Luo, Yalan Chen, Zequn Liu, Hengyi Fu, Mengmeng Zhao, Shishu Zhu, Ke Sun, Baoshan Xing
更新时间: 2026-10-19
摘要: Biochar (BC) displays great potential in stabilizing soil organic carbon, yet its decadal legacy for carbon preservation under redox oscillations remains unclear. The study comprehensively investigated how decadal BC (D-BC) application restrained carbon mineralization of paddy soil via reshaping reactive oxygen species (ROS) dynamics. In situ fluorescence imaging and quantification results showed that D-BC soil inhibited hydroxyl radical (•OH) generation by 22.3% than fresh BC (F-BC) input soil, but elevating hydrogen peroxide (H2O2) and superoxide (O2•–) accumulation by 36.2% and 25.4% during redox oscillation, respectively. This resulted from its weakened microbial iron reduction and the lower reactivity of Fe(II), which significantly limited Fenton reactions. In contrast, a shift in the microbial community to redox-adapted taxa, lower catalase activity, and enriched dissolved inorganic carbon collectively facilitated the biogenic origin of H2O2 in D-BC soil. Scavenging and correlation analyses revealed that reduced •OH generation led to net suppression in CO2 emission from D-BC soil by >30% via upregulating the enzymatic latch, while enhanced H2O2 accumulation imposed oxidative stress on carbon-degrading microbes. Laboratory verifications confirmed the roles of surface oxidation and persistent free radical attenuation of aged BC in ROS redistribution. The failure of decadal straw (D-Straw) return to reproduce these phenomena suggested that the decadal BC legacy stemmed from a particular redox impact, rather than exogenous carbon input alone. The findings uncovered a new mechanism of BC-induced carbon stability, advancing understanding of the carbon cycle within redox-dynamic zones.

9. 题目: Mechanisms of biochar derived from chicken manure or rice straw that effectively immobilizes cadmium do not apply to sewage-sludge biochar
文章编号: N26101910
期刊: Journal of Hazardous Materials
作者: Fei Huang, Kai-Ming Liang, Jun-Chun Li, Zhi-Wen Hu, Long-Yong Lin, Yi-Rong Deng
更新时间: 2026-10-19
摘要: In order to explore immobilization characteristic and its possible mechanism of various feedstocks-based biochars, deriving from chicken manure (CMB), rice straw (RSB) and sewage sludge (SSB), the effect of three biochars on speciation transformation of Cd in soil was compared, and soil properties, microbial community diversity were also examined. The treatment of CMB and RSB reduced significantly the content of acid-extractable Cd by 53.62% and 41.18%, respectively, but this available fraction was increased by 23.44% after SSB treatment. Simultaneously, CMB and RSB treatment significantly increased the soil pH, CEC, TOC, AN, AP, TK, microbial biomass carbon, dehydrogenase, phosphatase, catalase and urease enzyme activity, while SSB treatment slightly increased AP and TK content, only decreased urease enzyme activity. Lower bacterial alpha diversity was observed at the initial sampling of day 0, whereas treatment differences in bacterial Shannon diversity were not significant at day 225, it suggested that their effects on microbial alpha diversity were dependent on sampling stage and microbial kingdom. Partial least squares modelling (PLS-PM) speculated that CMB and RSB treatment decreased available Cd through direct effect of biochar and indirect effect of soil, whereas SSB treatment elevated available metal by indirect effect. This increase might be due to the decrease of urease activity indirectly affected by SSB, thus decelerating Cd precipitation and enhancing available Cd. These results deepen our understanding on the degree of immobilization and underlying mechanisms for Cd in soil that is critical for evaluating the application of effective biochar treatments.

10. 题目: Optical properties of colored dissolved organic matter and their importance in the hypersaline Arabian Gulf to assess the status of the ecosystem and its influence on the northwestern Indian Ocean biogeochemistry: a review
文章编号: N26101909
期刊: Environmental Monitoring and Assessment
作者: Turki Al-Said, N V H K Chari, Rakhesh Madhusoodhanan
更新时间: 2026-10-19
摘要: This review summarizes the existing knowledge on the sources, composition, transformation, and biogeochemical importance of dissolved organic matter (DOM) in aquatic environments, based on observations of its optically measurable fraction, known as chromophoric dissolved organic matter (CDOM). Optical methods, including UV–visible absorption and fluorescence spectroscopy, spectral radiometry, and hyperspectral satellite remote sensing, provide valuable information on the distribution and dynamics of DOM, which are closely linked to physical transport, microbial transformations, and photochemical degradation in coastal and marine environments. The Arabian Gulf (AG) represents a distinct marine environment characterized by shallow bathymetry, hypersalinity, large seasonal temperature variability, semienclosed circulation, restricted water exchange, and relatively long residence times. These conditions, together with intense solar radiation, osmotic stress, limited terrestrial freshwater inputs, and increasing anthropogenic pressures, can strongly influence the sources, composition, and transformation of DOM. Within this dynamic environment, DOM may undergo transformations driven by seasonal biological production, benthic–pelagic interactions, sedimentary processes, and anthropogenic inputs, followed by further biological and photochemical processing. The formation of Persian Gulf water (PGW) mass in the AG and its export through the Strait of Hormuz into the subsurface waters of the northern Arabian Sea as a density-driven outflow may influence oxygen minimum zone (OMZ) dynamics and contribute to carbon biogeochemical cycling in the northern Indian Ocean. Despite the importance of these processes, significant knowledge gaps remain regarding the sources, composition, transformation, and fate of CDOM and its role in carbon cycling in the AG. Consequently, integrated in situ and remote sensing approaches for characterizing CDOM are essential to improve our understanding of DOM dynamics and carbon biogeochemical processes in the AG and in the northern Indian Ocean, particularly in the context of ongoing environmental and global climate change.

11. 题目: Comparative Phenol Adsorption by KOH-modified Biochar and Hydrochar: Synthetic Water, Real HTC Liquid, and Multi-criteria Assessment
文章编号: N26101908
期刊: Water, Air, & Soil Pollution
作者: Afshin Maleki, Nader Marzban, Nader Amini, Hee-Jeong Choi, Serveh Fathi, Zakaria Vahabzadeh, Shadi Kohzadi, Kazem Godini
更新时间: 2026-10-19
摘要: Hydrothermal carbonization (HTC) produces an aqueous by-product containing dissolved organic matter, including phenolic and aromatic constituents, that must be managed before discharge or reuse. In this study, biochar (BC), hydrochar (HC), and their KOH-modified forms (BC–KOH and HC–KOH) were compared for phenol removal from synthetic solutions and for apparent phenol-response reduction in real HTC process liquid. After an initial screening step, the modified materials were examined with respect to solution pH, adsorbent dose, adsorption kinetics, equilibrium behavior, temperature response, co-existing ion effects, real-matrix treatment, and regeneration. A supplementary multi-criteria decision-support framework based on TOPSIS, VIKOR, and Pareto screening was used to summarize the most application-relevant performance indicators. BC–KOH was identified as the most effective adsorbent under the tested conditions. Under baseline screening conditions, phenol removal reached 89.7% for BC–KOH and 81.5% for HC–KOH. In real HTC process liquid, BC–KOH achieved 75.7% apparent phenol-response reduction and 38.7% COD reduction, compared with 66.6% and 32.1%, respectively, for HC–KOH. The kinetic data were best described by the pseudo-second-order model, while Weber–Morris and Boyd analyses indicated contributions from both film diffusion and intraparticle diffusion. Freundlich gave the lowest AICc for both equilibrium datasets; this preference was clear for BC–KOH, whereas Langmuir and D–R remained within ΔAICc < 2 of Freundlich for HC–KOH. The equilibrium evidence therefore supports non-uniform surface affinity most strongly for BC–KOH and more cautiously for HC–KOH. Kd-based apparent temperature-response indicators showed that phenol uptake increased moderately with temperature, and regeneration tests showed better adsorption-performance retention under alkaline desorption than under acidic desorption. Overall, BC–KOH was identified as the more promising adsorbent for phenol removal in synthetic water and for selective apparent phenol-response reduction in HTC-derived aqueous streams. However, the real-matrix results should be interpreted as standard-method-based apparent phenol response rather than compound-specific phenol quantification, and adsorption should be considered as part of an integrated treatment strategy rather than a stand-alone solution for complete COD removal.

12. 题目: Synergistic effects of biochar and organic fertilizer on the regulation of microbial carbon and nitrogen metabolism in paddy soil to reduce net greenhouse gas emissions
文章编号: N26101907
期刊: Journal of Environmental Management
作者: Xiaoqiang Cao, Zhennan Zang, Jilong Liu, Guolong Zhan, Guoxin Shi, Lingling Zhang
更新时间: 2026-10-19
摘要: Biochar and organic fertilizer have been widely applied to improve soil carbon sequestration and mitigate greenhouse gas (GHG) emissions in rice production systems. However, the synergistic mechanisms through which these amendments regulate microbial carbon/nitrogen (C/N) metabolism, net GHG emissions, and crop productivity in dry direct-seeded rice (DDSR) systems remain insufficiently understood. In this study, a two-year field experiment was conducted with combined treatments of organic fertilizer substitution (0% and 20%) and biochar application (0, 5, and 10 t/hm2) to evaluate their integrated effects on GHG emissions, soil properties, rice yield, and microbial functional genes involved in C/N cycling. Biochar and organic fertilizer significantly reduced CH4 and N2O emissions, leading to lower global warming potential (GWP), greenhouse gas emission intensity (GHGI), and net greenhouse gas emissions (NGHGE), while simultaneously increasing rice yield. The combined application of 20% organic fertilizer substitution with 5 t/hm2 biochar achieved the optimal performance, increasing yield by 11.64%–15.44% and reducing GWP and GHGI by 7.58%–16.56% and 17.21%–27.72%, respectively. Metagenomic analysis revealed that the combined application modified microbial community structure while regulated microbial C/N metabolism by reshaping key functional pathways. The enhancement of Calvin-Benson-Basham (CBB) pathway was related to the increased abundance of PRK and prkB under biochar conditions; meanwhile, reduced abundances of aclA, aclB, and ccsA were associated with suppressed reductive tricarboxylic acid (rTCA) cycle. Concurrently, denitrification and nitrification pathways showed positive correlations with increased abundances of nirK, norB, and nosZ. Redundancy analysis (RDA) and mantel analyses indicated that soil organic carbon (SOC), pH, ammonium nitrogen (NH4+-N), and nitrate nitrogen (NO3−-N) were the primary drivers shaping microbial functional gene structure. Overall, the synergistic application of biochar and organic fertilizer effectively coordinated carbon sequestration, emission reduction, and yield enhancement, providing a feasible strategy for low-carbon and sustainable management of DDSR.

13. 题目: Fire removes preexisting pyrogenic organic matter from the ecosystem through the mechanisms of both direct combustion and increasing mineralizability
文章编号: N26101906
期刊: Biogeochemistry
作者: Mengmeng Luo, Kara Yedinak, Keith Bourne, Thea Whitman
更新时间: 2026-10-19
摘要: Pyrogenic organic matter (PyOM) produced during fires plays an important role in the global carbon (C) cycle due to its low microbial availability and resulting high persistence. However, PyOM can be combusted or chemically altered in subsequent fires. To explore the effects of subsequent fire on PyOM, we used a mass loss calorimeter to simulate reburning by delivering realistic heat fluxes to jack pine (Pinus banksiana Lamb.) PyOM produced at 350 °C. We tested three heat flux profiles (High, Low, and Control) and three burial depths (Surface, 1 cm, and 5 cm) arranged in a full-factorial design, with the “high” heat flux profile consisting of heating for 4.72 h with a peak of 85 kW m−2 and “low” heating for 2.5 h with a peak of 45 kW m−2. We found that both variables affected the C remaining after the simulated reburn (p < 0.05), with greater C losses at higher heat fluxes and shallower exposure depths. Consistent with our predictions, treatments with high heat exposure (HFHigh + Surface, HFHigh + 1 cm, HFLow + Surface) showed increases in pH and decreases in total dissolved organic carbon (DOC) and mineralized C after the simulated reburn. Counter to our predictions, treatments with intermediate reburn conditions (HFHigh + 5 cm and HFLow + 1 cm) caused decreases in pH and increases in DOC, mineralized C, modelled decomposable C, and modelled C decomposition rate (p < 0.05), compared to the unburned controls. These findings highlight that, despite its high persistence in fire-free conditions, PyOM can also be readily combusted and altered in subsequent fires, with important implications for changing fire regimes and the global C cycle.

14. 题目: Biochar Synthesis from Watermelon Rind Waste: Characterization of Physicochemical and Adsorption Properties
文章编号: N26101905
期刊: Water, Air, & Soil Pollution
作者: Ahmed M Kamil, Anitha C Kumar, Jephin K Jose, Sabu Thomas
更新时间: 2026-10-19
摘要: In recent years, sustainable and cost-efficient wastewater treatment technology has been pursued using biomass-based adsorbents. This study investigates the conversion of watermelon rind into biochar (WRB), comparing its yields, physicochemical properties, and adsorption capacities across three pyrolysis temperatures at two residence times. The biochar produced from watermelon rind was 37.5%, 32.6%, and 30.6% at 400, 500, and 600 °C, respectively, at a residence time of 1 h. When the residence time was extended to 3 h, the yields decreased to 33.9%, 29.8%, and 25.9%, respectively. Proximate analysis presents increased fixed carbon and reduced volatile content. Ultimate analysis, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR) spectra expose structural differences exhibiting higher aromatic content at elevated pyrolysis temperatures, while pyrolysis-induced loss of functional groups like hydroxyl (O–H) and carboxyl (-COOH) bonds diminished biochar adsorption properties. The biochar produced at 400 °C in 1 h exhibited the highest adsorption capacity. The effects of initial concentration of safranine dye (SMS), contact time, pH, and temperature on adsorption efficiency were measured through batch adsorption experiments. The experimental results were fitted using the Langmuir isotherm (qmax = 34.965 mg g−1) and pseudo-second-order model. The adsorption process is found to be spontaneous and endothermic. The results suggest that biochar can be used as an effective, economical, and eco-friendly adsorbent in the removal of cationic dyes in our experiment and has great potential in terms of large-scale treatment of wastewater.

15. 题目: Predominance of Externally Mixed Black Carbon Over the Tibetan Plateau During the Asian Summer Monsoon
文章编号: N26101904
期刊: Geophysical Research Letters
作者: Shaowen Zhu, Biao Luo, Nan Ma, Pengfei Yu, Zheng Yang, Min Tang, Junwen Liu, Weiwen Wang, Yaqing Zhou, Juan Hong, Yunfei Wu, Liang Ran, Zhaoze Deng, Zhixuan Bai, Jiandong Wang, Weiwei Hu, Shan Huang, Jianchun Bian, Qiaoqiao Wang, Hang Su, Yafang Cheng
更新时间: 2026-10-19
摘要: The mixing state of black carbon (BC) strongly influences its lifetime and radiative forcing over the Tibetan Plateau (TP). Previous observations, mostly conducted during the non‐monsoon season, suggested that thickly coated BC dominates due to long‐range transport from South Asia. Here we report near‐surface BC mixing state measurements during the 2021–2023 summer monsoons at seven sites across the central–southern TP. We find that BC predominantly exists as bare/thinly‐coated state (externally mixed), with fractions of 73.2%–93.7%, much higher than earlier reports (20%–60%). This mainly arises from suppressed transport from South Asia during the monsoon season and intrinsically slow coating‐growth over the TP. The prevalence of externally mixed BC implies weaker absorption enhancement and CCN activity. These results underscore the need to represent seasonal variability of BC mixing state over the TP in climate models.

16. 题目: Petagram‐Scale Dissolved Organic Carbon Stocks in Alaskan Permafrost Soils
文章编号: N26101903
期刊: Geophysical Research Letters
作者: Yongni He, Songfan He, Jack A Hutchings, Mikhail Kanevskiy, Yongge Sun, Xiaowen Zhang
更新时间: 2026-10-19
摘要: The pan‐Arctic permafrost region hosts vast amounts of soil organic carbon, a pool increasingly susceptible to climate‐driven changes. Dissolved organic carbon (DOC) is a key component of this carbon pool. However, its stocks and fluxes remain poorly understood due to limited measurements and challenges of tracking subsurface fluxes across landscapes. Through continuous leaching experiments on Alaskan soil samples, we established a statistical relationship between the percentage of leached soil carbon as DOC (DOC yield) and soil total organic carbon content (TOC) ( y = 5.11× −0.43 , R 2 = 0.59). After validating this relationship against literature data, we applied it to estimate effective permafrost soil DOC stocks in Alaska, yielding 1.72 (1.01−2.66) Pg C for the 0–3 m depth interval and 0.53 (0.24−1.00) Pg C for the active layer. Our results highlight the importance of the permafrost soil DOC pool, and the robust quantification method offers insights for future pan‐Arctic DOC release assessments.

17. 题目: Global grassland productivity and carbon storage benefit from functional diversity under climate change
文章编号: N26101902
期刊: Proceedings of the National Academy of Sciences of the United States of America
作者: Stephen Björn Wirth, Christoph Müller, Friedhelm Taube, Jens Heinke, Britta Tietjen, Susanne Rolinski
更新时间: 2026-10-19
摘要: Functional diversity plays an important role for ecosystem services of managed grasslands such as their gross primary productivity (GPP) and soil organic carbon (SOC) stocks. Yet vegetation models assessing functional diversity have been limited to small spatial scales. We used the Lund-Potsdam-Jena managed land (LPJmL) competitor stress-tolerant ruderal (CSR) model to assess the role of functional diversity for managed grassland GPP and SOC under climate change at the global scale. LPJmL-CSR simulates functional diversity using plant functional types representing different ecological strategies based on functional traits connected to CSR strategies. Our simulation experiments assumed low and high functional diversity levels and moderate and strong climate change scenarios. Results show that functional diversity plays an important role for GPP and SOC stocks already under moderate climate change. Strong loss of functional diversity prohibits communities’ adaptation to climate change, resulting in loss of GPP and SOC. Spatial patterns of GPP and SOC stocks show substantial differences between the low and high functional diversity scenarios dependent on regional conditions. These results are consistent with empirical findings and support the importance of functional diversity as insurance against climate change. The results of our global-scale model assessment show that enhancing functional diversity could be crucial for maintaining grassland productivity and thus human well-being under global change. In combination with empirical findings, they underpin the need for management practices that support functional diversity of managed grasslands.

18. 题目: Sea level-induced oyster reef accretion causes minimal net carbon burial change
文章编号: N26101901
期刊: Nature Geoscience
作者: Antonio B Rodriguez, Justin T Ridge, Molly C Bost, Naomi Nice, Eve Eisemann, Yasamin Sharifi, Joshua D Himmelstein, F Joel Fodrie
更新时间: 2026-10-19
摘要: Nature-based infrastructure, such as oyster reefs and salt marshes, is increasingly being promoted as effective breakwaters to protect communities from storm waves and as carbon burial hotspots to mitigate greenhouse gas emissions. The function of oyster reefs as breakwaters and carbon sinks is commonly supported by information extracted from extant reefs <10 years old; however, both services depend on sediment accumulation, which operates over decadal to millennial timescales. Here we show that the rate of sea-level rise (SLR) drives eastern oyster reef vertical accretion and carbon burial. As relative SLR increased after 1800 CE to the modern rate of ~2.4 mm yr−1, intertidal reefs accreted vertically and accumulated sediment three times faster than during the previous 18 centuries when SLR was ~0.9 mm yr−1. Reef accretion rates were driven by the flux of shell and organic-rich sediments to the subsurface; however, none of the 25 reefs sampled functioned as net carbon sinks because the organic carbon buried was offset by the CO2 emitted during shell formation. Our results suggest that, as SLR accelerates, the vertical growth of healthy reefs has the potential to rapidly respond, with reefs becoming larger sources of CO2 but maintaining their effectiveness at damping waves. The ongoing deterioration of estuarine conditions needed to sustain healthy oyster reefs cautions against projecting these ecosystem service trade-offs into the future.

19. 题目: Removal of Cadmium and Lead From Aqueous Solutions by Biosulfur-modified Rice Husk Biochar: Adsorption Characteristics and Mechanisms
文章编号: N26101812
期刊: Water, Air, & Soil Pollution
作者: Youngkyu Hong, Jinwook Kim, Dongju Lee, Sungchul Kim
更新时间: 2026-10-18
摘要: Biological desulfurization of landfill gas generates biosulfur (BS) as a by-product, highlighting the need for effective resource-recovery strategies. In this study, BS was incorporated into rice husk biochar (BC) to produce biosulfur-modified biochar (BCBS), and its adsorption behavior toward Cd2⁺ and Pb2⁺ in aqueous solution was compared with that of unmodified BC. The optimal BCBS preparation condition was mixing BC with BS in deionized water for 1 h, resulting in a sulfur content of 48.6%. Elemental analysis, SEM–EDS, FTIR, XRD, and XPS were used to characterize BCBS and investigate the adsorption mechanisms before and after metal uptake. Both metals exhibited rapid initial adsorption, and the kinetic data were better described by the pseudo-second-order model, suggesting the importance of surface-mediated interactions without confirming a single chemisorption mechanism. The maximum Langmuir adsorption capacities of BCBS were 13.9 mg g⁻1 for Cd2⁺ and 102.0 mg g⁻1 for Pb2⁺, approximately 5.0 and 15.5 times higher, respectively, than those of BC. FTIR and XPS analyses indicated that sulfur-containing surface components, including sulfide- and sulfate-related species, contributed to metal binding, whereas XRD revealed no detectable crystalline Cd- or Pb-bearing precipitates. These findings demonstrate that biologically recovered sulfur can be effectively recycled as a biochar-modifying material through a simple water-based process, producing a promising adsorbent for Cd2⁺ and Pb2⁺ removal from aqueous systems.

20. 题目: Perturbation of dissolved organic matter reactivity by tributary inflows in a large reservoir unveiled by reactomics and explainable machine learning
文章编号: N26101811
期刊: Journal of Hydrology
作者: Qiaoqiao Li, Hai Huang, Mingxing Cao, Yixuan Ye, Yuhan Jiang, Hua Ma
更新时间: 2026-10-18
摘要: River confluences serve as biogeochemical hotspots in watersheds, yet the molecular-level mechanistic linkage between tributary-induced perturbations in dissolved organic matter (DOM) and their functional consequences for ecosystem processes remains poorly quantified. Here, we integrated ultrahigh-resolution mass spectrometry, reactomics (inference of reactivity potential networks from periodic mass difference analysis), and explainable machine learning across four confluences in the Three Gorges Reservoir (TGR). We demonstrate that despite tributaries delivering chemically distinct DOM pools, which distinguish urban-derived, protein-like molecules from terrestrial, aromatic compounds, their mixing with the mainstem is predominantly conservative. In contrast, functional profiling revealed that tributary DOM possesses higher intrinsic reactivity potential, with oxidoreductase pathways dominating the reaction network. A discharge-weighted mixing model confirmed overall conservatism in reactivity potential: measured values deviated from conservative predictions by less than ± 5%. We identified a critical exception: a low-discharge tributary created a disproportional reactivity potential hotspot, underscoring that even minor inputs can drive non-conservative processes. Explainable machine learning (SHAP) showed that higher O/C and NOSC values were associated with greater DOM reactivity potential, while higher S/C values were associated with lower reactivity potential. These three features together accounted for > 90% of feature importance, and the site-grouped cross-validated R2 (3 folds) of the XGBoost model ranged from 0.72 to 0.73 across the four reaches (mean = 0.73). Our findings, based on this synoptic survey, establish a framework that links molecular traits to DOM reactivity potential, providing predictive insights for managing carbon cycling and water quality in regulated river systems.