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221. 题目: Temporal effects of precommercial thinning on dissolved organic carbon leaching in pine–oak mixed forests
文章编号: N26083105
期刊: Catena
作者: Qian Wang, Menglin Su, Zi'’ao Liang, Xiangfu Wang, Shuiqiang Yu, Weifeng Wang
更新时间: 2026-08-31
摘要: As a critical process in hydrological and biogeochemical cycles, soil leaching transports dissolved organic carbon (DOC) from terrestrial to aquatic ecosystems. Precommercial thinning (PCT), an important silvicultural practice of forest management, affects forest biogeochemical cycling, particularly DOC leaching. However, the effects of PCT on DOC leaching dynamics over recovery time remain poorly understood. To clarify the temporal effects and mechanisms of PCT, we investigated DOC leaching across a PCT recovery sequence namely, PCT in 2010 (T2010), PCT in 2018 (T2018), and the unthinned control (CK) in a pine–oak secondary forest. The results revealed that soil DOC leaching fluxes increased initially (T2018: 18.64 ± 0.43 kg C ha−1 yr−1) but recovered to non-PCT levels (CK: 16.54 ± 0.57; T2010: 17.86 ± 0.32 kg C ha−1 yr−1), with a similar intensifying effect observed for the litter DOC leaching flux (T2018: 248.08 ± 4.62; CK: 200.40 ± 4.95; T2010: 198.77 ± 3.11 kg C ha−1 yr−1). Mechanistically, PCT reshaped the soil physical structure by modulating bulk density and capillary-to-noncapillary porosity ratio, thereby reducing water leaching flux. Simultaneously, the PCT recovery sequence promoted soil DOC concentrations by reducing soil sorption capacity and enhancing soil organic carbon accumulation driven by greater litter inputs and microbial biomass. These findings demonstrate that PCT alters forest hydrological and biogeochemical cycles, thereby affecting soil DOC export. This study enhances the understanding of PCT impacts on forest carbon and water dynamics, providing empirical evidence for optimizing PCT strategies to balance forest carbon sequestration and DOC inputs in aquatic ecosystems.

222. 题目: Blocking the “Trojan Horse” effect: Humic acid alleviates the combined toxicity of amino-modified nanoplastics and tetracycline to microalgae by inhibiting heteroaggregation and oxidative stress
文章编号: N26083104
期刊: Journal of Environmental Management
作者: Gopi Narayanan, Xiangyi Guo, Mohmmed Talib, Gopala Krishna Darbha, Saiyong Zhu, Daohui Lin, Jonathan Y S Leung
更新时间: 2026-08-31
摘要: Given the ever-increasing accumulation of nanoplastics in aquatic environments worldwide, there is concern that plastic pollution will lead to ecological disasters due to the transfer of man-made pollutants, such as antibiotics, into aquatic life by nanoplastics. However, the intensity of this “Trojan Horse” effect may be influenced by natural organic matter that can interact with nanoplastics and antibiotics, possibly affecting their biological impacts. Thus, this study assessed how humic acid (HA, 10 mg L−1) modulates the combined effects of amino-modified polystyrene nanoplastics (NH2PS, 25 mg L−1) and tetracycline (TC, 5–15 mg L−1) on microalga Chlorella vulgaris following 96 h exposure. Results showed that exposure to TC and NH2PS, especially in combination, elicited various adverse effects on microalgae (e.g., membrane disintegration, mitochondrial dysfunction, growth retardation and impaired synthesis of photosynthetic pigments) due to elevated oxidative stress resulting from heteroaggregation between pollutants and algal cells. This adsorption of TC onto NH2PS created a carrier-enhanced delivery system that amplified cellular internalization of both pollutants, leading to persistent disruption of cellular homeostasis. Importantly, HA could ameliorate these toxic effects on microalgae as physicochemical characterization revealed that HA competitively reduced TC adsorption onto NH2PS surfaces and enhanced pollutant dispersion stability, thereby reducing the oxidative and membrane damage caused by direct contacts with pollutants. Overall, this study provides a mechanistic understanding of how natural organic matter mitigates the “Trojan Horse” effect of nanoplastics with antibiotics, suggesting that the ecological impacts of nanoplastics may be less severe than anticipated under realistic conditions. Such insights are crucial for refining ecological risk assessment and guiding nanoplastic pollution management.

223. 题目: Machine learning reveals reservoir regulation of riverine sedimentary organic matter and its climatic implications
文章编号: N26083103
期刊: Water Research
作者: Sibo Kang, Lei Huang, Hongzhu Wang, Yongde Cui, Wenjuan Gao, Chen He, Quan Shi, Chen Zhao, Ding He, Kai Wang
更新时间: 2026-08-31
摘要: Reservoirs play a pivotal role in riverine water resource management, while their influence on the cycling processes of riverine carbon remains to be further explored, constraining our comprehension of ecological impacts of reservoirs on terrestrial ecosystems. Here, we developed a machine learning (ML) model to characterize the dynamic of sedimentary organic matter (SOM) in the Yangtze River, one of the world’s largest rivers under the influence of the Three Gorges Reservoir (TGR), one of the world’s largest reservoirs. The TGR exhibited lower organic carbon (OC) and dissolved organic carbon (DOC) concentrations than the midstream of the Yangtze River (MYR), with mean values of 0.90 ± 0.20% and 1.58 ± 0.37 mg L-1, respectively, compared with 1.34 ± 0.45% and 2.60 ± 0.58 mg L-1 in the MYR. These differences suggested enhanced microbial processing and carbon elimination within the reservoir. Our ML model further revealed that the TGR promoted the in situ burial of heteroatom-poor, low-aromaticity organic matter (OM), while facilitating the downstream transport and subsequent deposition of microbially reworked, highly recalcitrant OM in the MYR. Combining with greenhouse gas (GHG) emission data from TGR to MYR, we found that this dynamic of SOM is involved severely in the decline of CO2 (∼60%) and CH4 (∼24%) emissions in the middle and lower reaches of the Yangtze River. This study highlights the potential of ML in the assessment of ecological impacts of reservoirs, and suggests that reservoirs contribute to GHG mitigation in downstream river systems.

224. 题目: Molecular evidence for algal bloom decay as a critical window for bacteria-mediated DOM transformation toward more refractory forms
文章编号: N26083102
期刊: Water Research
作者: Ziwei Zhang, Huanjun Zhang, Yi Li, Wangkai Fang
更新时间: 2026-08-31
摘要: Algal blooms profoundly alter the sources and composition of dissolved organic matter (DOM) in eutrophic lakes, with bacterial processes playing a central role in DOM transformation. However, how algal bloom succession reshapes bacteria-mediated DOM transformation and further influences the molecular fate of DOM remains unclear. Here, we integrated Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), paired mass distance (PMD)-based reactomics, and high-throughput sequencing to characterize DOM transformations and their microbial driving mechanisms across the pre-outbreak, outbreak, and decay stages of a natural algal bloom in a eutrophic lake. Across bloom succession, DOM molecular richness peaked during the outbreak stage, whereas molecular phylogenetic dispersion, aromaticity, and recalcitrance increased toward the decay stage, alongside reduced potential bioavailability. Relative to other stages, bacterially active DOM during the decay stage showed the highest relative intensity of biologically refractory DOM (i.e., tannin-like, condensed aromatic-like, and lignin-like compounds), along with higher aromaticity and unsaturation. PMD-based reactomics revealed the strongest reaction signatures during the outbreak stage, dominated by categories annotated as oxygenases acting on paired donors and acyltransferases, consistent with rapid DOM turnover. By contrast, decay-enriched reaction signatures, including categories annotated as intramolecular oxidoreductases, carbon–nitrogen lyases, and racemases/epimerases, suggested selective molecular transformation of DOM, potentially favoring molecular persistence. These findings highlight the algal decay stage as a critical window for bacteria-mediated DOM transformation toward more refractory forms, providing molecular-level evidence for microbial regulation of organic carbon persistence in eutrophic lakes.

225. 题目: Plastic-derived Dissolved Organic Matter Release from Agricultural Mulch Films: Impacts of Solar UV Weathering
文章编号: N26083101
期刊: Water Research
作者: Shahin Ahmed Sujon, Emma M Payne, Kyle J Moor
更新时间: 2026-08-31
摘要: Plastic mulch film coverings are increasingly used in sustainable agriculture production to better use water resources. As mulches weather in fields in contact with rainfall or irrigation water, they have potential to release a complex mixture of organic chemicals, often called plastic-derived dissolved organic matter (plastic-DOM). Photodegradation is a potentially important pathway for plastic-DOM generation, yet little is known about the quantities of plastic-DOM released from commercial biodegradable mulches during use. To address this unknown, we investigated the release of plastic-DOM from agricultural mulch films during ultraviolet (UV) weathering over growing season relevant timescales (months). We quantified the amount of plastic-DOM released from polyethylene (PE) and biodegradable mulches as a function of weathering conditions (in air or water) and time. We further assessed the composition of the mulch film plastic-DOM generated during weathering using fluorescence excitation-emission matrices (EEMs), which revealed formation of humic-like fluorescence signals in plastic-DOM from biodegradable mulch films with UV weathering. Results advance understanding on the quantities and composition of plastic-DOM released from mulches throughout the growing season, as a first step to estimate plastic-DOM’s impact on receiving soils, groundwaters, and surface waters.

226. 题目: Spectral preprocessing and machine learning models for prediction of subarctic climate woodland soil organic carbon and total nitrogen using Vis-NIR spectroscopy
文章编号: N26083009
期刊: Journal of Soils and Sediments
作者: Zhengxiang Xu, Qikai Lu
更新时间: 2026-08-30
摘要: Purpose Woodlands in subarctic climates are important for global carbon storage and sequestration, contributing significantly to climate stabilization. Accurate estimation of soil organic carbon (SOC) and total nitrogen (TN) is essential for managing these ecosystems. Methods This study applied visible and near-infrared (Vis-NIR) spectroscopy to predict subarctic climate woodland SOC and TN, where the performance of different spectral preprocessing and machine learning models were evaluated. To preprocess the spectrum, standard normal variates (SNV), normalization (NOR), multiplicative scatter correction (MSC), Savitzky-Golay smoothing with first derivative (SG1), and Savitzky-Golay smoothing with second derivative (SG2) were adopted. Meanwhile, partial least squares regression (PLSR), random forest (RF), support vector regression (SVR), extreme gradient boosting (XGBoost), light gradient boosting machine (LightGBM) and one-dimensional convolutional neural network (1D-CNN) were employed to model the relationship between Vis-NIR spectra and soil properties. A total of 1,368 soil samples collected from subarctic woodland of Finland and Sweden were used in the study. Results Experimental results demonstrated that Vis-NIR exhibits strong potential for estimating SOC and TN. Different spectral preprocessing approaches produced diverse results, with SG1 and SG2 outperforming the others. All machine learning models achieved satisfactory predictions, while the highest validation accuracies for both SOC (R2 = 0.949) and TN (R2 = 0.950) were achieved by the combination of SG1 and SVR. Conclusions This study offers both a theoretical reference and a practical framework for applying Vis-NIR spectroscopy combined with machine learning to support the monitoring and management of soil carbon and nitrogen in subarctic woodlands.

227. 题目: Vertical stratification of microbial necromass carbon and soil organic carbon fractions during natural secondary succession in temperate forests
文章编号: N26083008
期刊: Plant and Soil
作者: Gaoqiang Zhu, Guancheng Liu, Miao Wang, Xiaochun Wang, Liming Yin, Chao Liang, Yajuan Xing, Qinggui Wang
更新时间: 2026-08-30
摘要: Background and aims Natural secondary succession after clear-cutting is an important pathway for restoring forest soil organic carbon (SOC). However, how SOC fractions and microbial necromass carbon (MNC) vary among soil layers during succession remains unclear. Methods We investigated four natural secondary forests representing 20, 32, 47, and 61 years after clear-cutting and an undisturbed primary forest (> 200 years). Soil samples were collected from 0–10, 10–20, and 20–30 cm depths to quantify SOC, particulate organic carbon (POC), mineral-associated organic carbon (MAOC), MNC, and its contribution to SOC. Results SOC, POC, and MAOC increased significantly with succession across soil layers. POC contributed more to SOC at 0–10 cm, whereas MAOC contributed more at 10–30 cm. Fungal necromass carbon (FNC), bacterial necromass carbon (BNC), and MNC contents were significantly higher at 0–10 cm than at 20–30 cm across successional stages. The relationship between MNC and POC tended to weaken with depth, whereas the MNC–MAOC relationship varied among soil layers. The regulation of SOC fractions exhibited soil depth-dependence. At 0–10 cm, forest succession indirectly influenced SOC fractions by altering soil abiotic properties and thereby regulating microbial biomass and MNC accumulation. In contrast, at 10–30 cm, SOC fractions were directly regulated by soil abiotic properties. Conclusions MNC stratification was closely associated with depth-dependent SOC accumulation during secondary succession. These findings suggest that forest management should prioritize natural secondary succession and consider depth-specific necromass accumulation and SOC stabilization when enhancing forest soil carbon sequestration.

228. 题目: Biochar and hydrochar for saline soil amelioration and rice seedling growth promotion
文章编号: N26083007
期刊: Journal of Soils and Sediments
作者: Shuoding Xiao, Yu Xie, Jingru Yi, Yumei Huang, Weijie Yan, Sile Liu, Cheng Yi, Zongnan Li, Zhichao Xiang, Zhi Zhou, Wei Luo
更新时间: 2026-08-30
摘要: Purpose This study aimed to evaluate the effectiveness of biochar (BC), KOH/ Fe2(SO4)3-modified biochar (MBC), hydrochar (HTC), and modified hydrochar (MHTC) in ameliorating coastal saline-alkali soil properties and promoting rice seedling growth, and to explore the underlying mechanisms. Methods A pot experiment was conducted under simulated saline conditions. Treatments included a control (CK), BC, MBC, HTC, and MHTC, each applied at 2% (w/w). Rice seedlings were cultivated for 30 days. Soil physicochemical properties, enzyme activities, plant growth parameters, nutrient uptake, and ion homeostasis were analyzed. Results Compared with CK, all amendments significantly reduced soil electrical conductivity and sodium (Na⁺) content, while increasing soil organic carbon, cation exchange capacity, and the proportion of water-stable aggregates. Soil enzyme activities (urease, sucrase, catalase) were markedly enhanced. The amendments decreased Na⁺ accumulation and the Na⁺/K⁺ ratio in plants, improved nutrient (N, P, K) uptake, and increased seedling biomass. The synergistically modified material, MHTC, demonstrated the most comprehensive improvements across all measured parameters. Conclusions The synergistic KOH/Fe2(SO4)3 modification strategy significantly enhanced the functionality of carbon-based materials. MHTC effectively alleviated salt stress, improved soil properties, activated soil enzymes through integrated physicochemical and biochemical mechanisms, thereby substantially enhancing rice seedling growth. This study provides a promising novel material and strategy for the sustainable amelioration of saline-alkali soils.

229. 题目: Decrease of soil total and organic phosphorus with ectomycorrhizal tree dominance in a subtropical mountainous forest
文章编号: N26083006
期刊: Journal of Soils and Sediments
作者: Mi Yang, Mengzhen Lu, Long Chen, Qiuxiang Tian, Xiaorong Wang, Zhiyang Feng, Zhongfeng Sun, Feng Liu
更新时间: 2026-08-30
摘要: Aims Arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) plants differ in phosphorus (P) uptake strategies and litter quality, but the covariant relationship between tree mycorrhizal dominance and soil total phosphorus (TP) and its fractions along the natural gradient remains unclear. This study aims to elucidate the association between tree mycorrhizal symbiosis and soil P dynamics. Methods We established 35 plots across an AM and ECM tree dominance gradient. Soil P fractions were determined using the modified Hedley method. Plant traits, litter quality, soil properties, and microbial communities were analyzed to identify driving mechanisms. Results Soil TP, organic P (Po), and primary mineral P (HCl-Pi) decreased significantly with increasing ECM tree dominance. TP content was negatively related to the basal area of trees and the thickness of forest floor, and positively correlated with community-weighted-mean litter P content. Reduced TP was mainly driven by stronger aboveground P translocation and lower litter P input. Declines in Po and HCl-Pi were attributed to covaried with elevated mineralization and dissolution potential linked to soil enzymes, phosphorus-solubilizing microorganisms (PSM), and low pH. Conclusions Increasing ECM dominance was associated with decreased TP and Po pools in the soil, accompanied by increased acid phosphatase activity and increased abundance of PSMs recruited by ECM fungi. This study elucidates how mycorrhizal tree dominance synergistically changes with soil P fractions transformation and microbial P-activating functional groups in weathered subtropical forest soils.

230. 题目: Observed associations between recovery of soil organic matter, nitrogen, and potassium and microbial community reassembly along a 30-year vegetation restoration chronosequence in eroded subtropical red soils
文章编号: N26083005
期刊: Plant and Soil
作者: Cheng Lin, Yiqun Wu, Yang Xiao, Xiangzhou Zheng
更新时间: 2026-08-30
摘要: Background and Aims Vegetation restoration rehabilitates eroded subtropical red soils, but long-term dynamics of soil fertility and microbial community recovery remain unclear. This study evaluated changes across a 30-year restoration chronosequence. Methods Using a space-for-time substitution design (0, 12, 20, and 30 years) in a severely eroded region of southern China, we measured soil physicochemical properties, microbial diversity, community assembly, and predicted functions. Results After 30 years, soil organic matter increased by 435% (to 22.03 g/kg), total nitrogen by 343% (0.62 g/kg), and available potassium by 461% (95.33 mg/kg). Bacterial ACE diversity rose from 518.7 to 1123.7, and fungal from 59.3 to 364.1. Community composition shifted from oligotrophic taxa (e.g., Candidatus Eremiobacterota) in degraded soil to copiotrophic taxa (e.g., Planctomycetota, Bryobacter) and symbiotic fungi (e.g., Glomeromycota, Basidiomycota) in later stages. Redundancy analysis identified available potassium and phosphorus as key factors for bacterial reassembly, while pH and total phosphorus associated more with fungal communities. Functional predictions indicated higher relative abundance of ASVs with predicted nitrogen-fixation versus denitrification capacities after long-term restoration. Correlation analysis revealed significant associations between bacterial phyla and soil nutrients. Conclusion Long-term vegetation restoration was associated with the rebuilding of soil fertility and a shift toward diverse, functionally structured microbial communities dominated by copiotrophic and symbiotic taxa. Although causal inference is precluded by the space-for-time substitution design with one site per restoration stage, our findings reveal observational associations between vegetation restoration and the recovery of soil organic matter and key nutrients within this specific chronosequence.

231. 题目: Root Fe plaque mediates microbial Fe cycling: trade-off effects on soil organic carbon preservation and mineralization in flooded paddy soil
文章编号: N26083004
期刊: Plant and Soil
作者: Yuyao Luo, Jianbo Chen, Chengshuai Liu, Manjia Chen, Xinyu Li, Zixian Wang, Jiangtao Qiao, Fei Huang, Hui Tong
更新时间: 2026-08-30
摘要: Background and aims Root iron (Fe) plaque is a key interface between the rhizosphere and soil that critically influences organic carbon cycling. However, the mechanisms through which Fe plaque drives carbon preservation and mineralization, as well as its role in rhizosphere-mediated carbon emissions, remain poorly understood. Methods We quantified Fe plaque abundance, carbon-degrading enzyme activity, CO2 and CH4 emission rates, Fe-bound soil organic carbon (Fe-SOC), microbial community structure, and functional gene abundance to investigate SOC transformation in a pre-induced Fe plaque treatment (IP) and a non-pre-induced control (CK) under flooded paddy soil conditions. Results Fe plaque significantly increased soil CO2 and CH4 emissions by 27.4% and 31.2% (p < 0.01), respectively. Geobacter-related Fe-reducing bacteria (FeRB) copy numbers were 32.5% and 19.9% (p < 0.05) higher in rhizosphere soil and roots of the IP treatment than in CK, respectively. Carbon-degrading enzyme activities were also elevated by 13.7%-37.2% in IP. Fe-SOC showed a phase-dependent pattern, increasing to 2.86 g kg−1 during the first 3 days in IP, significantly higher than CK (p < 0.01), but subsequently decreasing by 62.3% from days 3 to 28. These results indicate an early Fe-associated carbon-preservation response followed by later destabilization of Fe-associated carbon and enhanced carbon mineralization under increasingly reducing conditions. Conclusion Fe plaque acted as a phase-dependent regulator of SOC dynamics rather than a permanent carbon sink. Enhanced initial plaque formation was associated with short-term Fe-associated carbon retention, but prolonged flooding promoted Fe-SOC destabilization and greater carbon mineralization. These findings highlight the need to consider redox-dependent Fe–C cycling when evaluating SOC storage and greenhouse-gas emissions in paddy soils.

232. 题目: Adsorption Performance and Mechanism of Ni(II) by EDTA-Catalyzed Mg/Al Hydroxide-Modified Biochar
文章编号: N26083003
期刊: Water, Air, & Soil Pollution
作者: Weiping Sima, Jiang Qu, Qibin Xu, Hengjun Tang, Lin Wang
更新时间: 2026-08-30
摘要: With the acceleration of industrialisation, heavy metal pollution has become an increasingly severe problem. Among various heavy metals, nickel ions not only disrupt ecological balance but also pose a significant threat to human health. Consequently, developing efficient methods for removing nickel ions from wastewater has become a key focus in environmental research. To address this challenge, this study successfully synthesised magnesium–aluminium layered double hydroxide-modified biochar (MBC) using ethylenediaminetetraacetic acid (EDTA) as a catalyst and distiller's grains as raw material. Subsequently, the adsorption characteristics of MBC towards Ni(II) and its underlying mechanism were thoroughly analysed. Experimental results indicate that under reaction conditions of pH 6.0, a biochar dosage of 1.25 g/L, and initial Ni(II) concentrations ranging from 25 to 150 mg/L, MBC exhibits optimal adsorption performance for Ni(II). The adsorption capacity of MBC for Ni(II) reaches 78.10 mg/g, achieving a removal rate as high as 97.62%. These results clearly demonstrate that Mg–Al layered double hydroxide (LDH)-loaded biochar exhibits outstanding removal performance for Ni(II). By fitting adsorption kinetics and isotherm models, we confirmed that Ni(II) adsorption onto biochar conforms to pseudo-second-order kinetics and Langmuir isotherm models. Furthermore, adsorption mechanisms were investigated in depth using characterisation techniques such as Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS). Results confirmed that MBC adsorption of Ni(II) primarily occurs through the synergistic effects of surface coordination, electrostatic interactions, complexation, ion exchange, and π-electron interactions. Collectively, these findings provide crucial theoretical support for the application of modified biochar in treating heavy metal-contaminated wastewater.

233. 题目: Depth-dependent differentiation of plant- and microbial-derived carbon formation pathways drives soil organic carbon responses to straw incorporation and asymmetric warming in paddy soils
文章编号: N26083002
期刊: Plant and Soil
作者: Pan Hou, Qiaogang Yu, Qi Shen, Zhaoming Chen, Qiang Wang, Jun Zhou, Xiaofang Zhu, Lijun Gao, Kangqi Lei, Jingwen Gao, Junwei Ma, Feng Wang
更新时间: 2026-08-30
摘要: Background and Aims Asymmetric warming and straw incorporation are key drivers of soil organic carbon (SOC) in paddy soils, yet their combined effects on plant- and microbial-derived carbon (C) across soil depths remain unclear. We examined how these factors regulate SOC across depths. Methods A four-year straw × warming experiment was conducted in a rice–wheat paddy. In topsoil (0–20 cm) and subsoil (20–40 cm), lignin phenols and amino sugars were measured as biomarkers of plant- and microbial-derived C, together with phospholipid fatty acids and C-acquiring enzymes. Random forest analysis identified predictors of each C pool. Results Straw incorporation increased topsoil SOC by 8.8% while warming reduced it by 6.1%, with a significant interaction offsetting the warming-induced loss; subsoil SOC was unaffected by straw but rose 6.2% under warming. In the topsoil, straw raised total lignin phenols and microbial necromass C by 24.1% and 26.6%, with fungal necromass C increasing more than bacterial. In the subsoil, warming raised lignin phenols by 23.3% via suppressed oxidative decomposition and microbial necromass C by 12.4%, mainly through a 53.4% increase in bacterial necromass C. The SOC/total nitrogen ratio and fungal biomass were the top topsoil predictors, versus oxidative enzymes and bacterial biomass in the subsoil. Conclusion Straw incorporation sustains topsoil SOC by promoting fungal necromass that offsets warming-induced lignin loss, whereas asymmetric warming raises subsoil SOC by suppressing lignin decomposition and stimulating bacterial necromass. Both plant- and microbial-derived C pathways should therefore be integrated into SOC models for paddy systems under future climate.

234. 题目: Four Decades of Straw and Manure Application Differentially Alter DOM Composition and Transport Risk in a Vertisol
文章编号: N26083001
期刊: Water, Air, & Soil Pollution
作者: Xin Yang, Yanfeng Zhang, Min Xia, Peixuan Wang, Zhibin Guo, Lin Jin, Linchuan Zhan, Daozhong Wang, Keke Hua
更新时间: 2026-08-30
摘要: Dissolved organic matter (DOM) loss from agricultural systems undermines soil carbon sequestration and water quality. While organic amendments are vital for soil fertility and crop productivity, their effects are highly amendment-specific. Critically, the quantitative relationship between long-term amendment types and the chemical composition of DOM-which governs its environmental mobility-remains poorly defined. Here, we quantified Dissolved Organic Carbon (DOC) concentration, DOM optical properties and fluorescent components in surface runoff and leachate from a 41-year field experiment on a Vertisol. Over three consecutive years, DOM from six fertilization regimes [no fertilizer (CK), mineral fertilizer (NPK), and NPK with low straw (NPK + LS), high straw (NPK + HS), pig manure (NPK + PM), or cattle manure (NPK + CM)] was characterized using excitation-emission matrix fluorescence with parallel factor analysis (EEM–PARAFAC). Contrasted with NPK, manure amendments markedly increased DOC concentrations and altered its composition. DOM in surface runoff increased by 25.4–44.7%, accompanied by a 16–28% rise in protein-like (C3) fluorescence. In leachate, DOC concentrations rose by 51.9–58.5%, while humic-like (C4) fluorescence nearly doubled (increases of 94.3–105.7%). Moreover, E2/E3 values were significantly reduced by 7.17–20.48% in surface runoff and 14.71–29.66% in leachate, whereas HIX (humification index) and BIX (bioavailability index) were increased by 35–90% and 44–65% in both pathways. Our study reveals manure, particularly cattle manure, poses a greater risk for DOM loss by increasing its concentration in leachate and runoff and altering its chemical properties compared to straw return. Straw return is therefore recommended as a sustainable strategy to reduce DOM pollution risk and enhance agricultural resilience to extreme precipitation.

235. 题目: Residual Disinfectant Controls The Biostability of Drinking Water Independent of The Concentration of Assimilable Organic Carbon
文章编号: N26082906
期刊: ACS ES&T Water
作者: Apoorva Goel, Timothy M LaPara, Raymond M Hozalski
更新时间: 2026-08-29
摘要: Assimilable organic carbon (AOC), residual disinfectant, and temperature were investigated as predictors of biological stability in 18 drinking water distribution systems (DWDSs). Surface water-supplied DWDSs exhibited significantly higher (p < 10–4) AOC concentrations (median = 50 μg/L; range = < LOD to 720 μg/L) compared to groundwater-supplied systems (median = 16 μg/L; range = < LOD to 156 μg/L). AOC levels were significantly higher (p < 10–4) during the summer months (August 2024 to October 2024) in surface water-supplied DWDSs than during the fall (October 2024 to December 2024). In contrast, AOC concentrations in groundwater-supplied DWDSs were similar during the summer and fall. Multivariate statistical analyses showed that residual disinfectant concentration was the strongest predictor of biostability, despite AOC concentrations in some systems being higher than the suggested threshold for biostability (50 μg/L) in disinfected DWDSs. Notably, decreases in AOC concentrations corresponded with increases in bacterial concentrations (measured as 16S rRNA gene copies) in systems where the residual disinfectant concentration was negligible at the distal location. This study, therefore, demonstrates that residual disinfectant concentration is a better predictor of biostability within DWDSs than AOC, even when AOC concentrations are significantly higher than the previously suggested threshold for biostability.

236. 题目: Effect of Biomass-Derived Biochar on Reactive Rejuvenated Styrene–Butadiene–Styrene-Modified Bitumen During Multiple Aging and Rejuvenation Cycles
文章编号: N26082905
期刊: ACS Sustainable Chemistry & Engineering
作者: Xiangjie Niu, Song Xu, Yiwen Zhang, Zihao Zeng, Zhilong Cao, Lei Fang, Hongyan Ma, Yan Yuan
更新时间: 2026-08-29
摘要: Reactive rejuvenation can restore the bitumen phase and reconstruct the styrene–butadiene–styrene (SBS) phase in aged SBS modified bitumen (SMB). However, reactive rejuvenated SMB still undergoes repeated aging during service. To enhance the aging resistance of reactive rejuvenated SMB, biomass-derived biochar was incorporated into the reactive rejuvenator to develop a biochar-modified reactive rejuvenator (BRR). The effect of biomass-derived biochar on reactive rejuvenated SMB during multiple aging and rejuvenation cycles (MARC) was investigated through physical property test, rheological test, toughness test, SARA fraction analysis, fluorescence microscopy test, and molecular dynamics simulations. Results show that BRR can restore the compositional balance of the bitumen phase and reconstruct the SBS phase in aged SMB, but its rejuvenation efficiency gradually declines with increasing MARC cycles. The large specific surface area and porous structure of particulate biochar absorb and stabilize light fractions in rejuvenated SMB, thereby weakening their dispersion and solubilization effects on heavy fractions and increasing the relative proportion of heavy fractions. This strengthens the rutting resistance of reactive rejuvenated SMB at the expense of its deformation resistance and low-temperature cracking resistance. Biochar can improve the aging resistance of rejuvenated SMB by protecting the bitumen phase rather than the SBS phase. This protection is attributed to its ability to absorb and stabilize light fractions in rejuvenated SMB, which reduces their loss during multiple aging cycles and retards the transition of the bitumen phase toward a gel-like colloidal structure.

237. 题目: Interfacial Unlocking by Functionalized Artificial Humic Acid Enables Sustainable Low-Temperature Pyrolytic Remediation of Petroleum-Contaminated Soil
文章编号: N26082904
期刊: Environmental Science & Technology
作者: Haohao Bian, Shunyu Yin, Jiamin Qi, Qunying Wang, Xiaona Ren, Xiaoyan He, Yidong Cai, Zhiguo Guo, Junmei An, Davronbek Bekchanov, Xintai Su, Changchun Ge
更新时间: 2026-08-29
摘要: Pyrolytic remediation of petroleum-contaminated soil (PCS) often requires high temperatures, which increase energy demand, limit resource recovery, and impair post-treatment soil functionality. This high-temperature dependence reflects not only the cracking resistance of heavy hydrocarbons, but also strong oil–soil interfacial locking that restricts their release and conversion. Here, we tested whether targeted interfacial regulation could lower remediation severity in PCS by using functionalized artificial humic acid (FAHA) as an interface-active mediator. Potassium citrate and lignin directed the molecular evolution of artificial humic acid, while Fe complexation introduced additional reactivity during pyrolysis. Under optimal conditions, FAHA2 at 0.5 wt % lowered the remediation threshold from 480 to 390 °C. Multiscale analyses suggested that FAHA reorganized the oil–mineral interface, weakened direct mineral–petroleum interactions, and facilitated lower-temperature release of interfacially constrained petroleum fractions. During pyrolysis, FAHA-bound Fe likely evolved from Fe–S-associated with Fe–O-rich coordination environments that could further facilitate hydrocarbon conversion. Compared with direct high-temperature pyrolysis, the FAHA-assisted pathway better preserved soil functionality and showed a lower estimated gross process-carbon burden under the defined accounting boundary. These results highlight sequential interfacial–thermochemical coupling as a design principle for more sustainable remediation of interface-dominated contaminated matrices.

238. 题目: Small Suspended Particulate Organic Carbon from Kelp Farming: A Neglected Pathway for Microbially Persistent Carbon Retention
文章编号: N26082903
期刊: Environmental Science & Technology
作者: Hongmei Li, Xiuting Feng, Shengkang Liang, Jianfu Man, Wei Shao, Shengrong Huang, Zhenwei Yan, Ding He, Yongyu Zhang
更新时间: 2026-08-29
摘要: Seaweed farming is increasingly recognized for its potential role in ocean carbon dioxide removal, yet the fate of small suspended particulate organic carbon (sPOC, 0.7–20 μm) released during macroalgal growth remains poorly constrained. Here, we investigated sPOC production, transformation, and microbial persistence in Sanggou Bay, China, one of the world’s most intensive Saccharina japonica cultivation systems. During the farming season, sPOC concentrations increased by 103.4% and 117.0% in surface and bottom waters, respectively, relative to the nonfarming period, accompanied by shifts in sPOC molecular composition toward kelp-derived signatures. In situ mesocosm experiments showed increasing sPOC release with kelp development, reaching 13.4–63.5 μmol L–1 over 64 h across growth stages. The 180-day microbial incubations revealed that 18.1–55.6% of kelp-derived sPOC was retained in three microbially persistent carbon pools: recalcitrant sPOC (R-sPOC; 7.6–27.3%), recalcitrant dissolved organic carbon (4.6–9.7%), and bicarbonate-associated inorganic carbon (5.9–18.6%). Residual R-sPOC exhibited molecular characteristics associated with enhanced microbial resistance, with formula-level evidence of direct kelp release and microbial transformation (48.2% and 51.8%, respectively). These findings identify sPOC as a neglected, mechanistically distinct carbon-retention pathway in seaweed farming and provide a basis for assessing its potential contribution to longer-term blue carbon sequestration.

239. 题目: Ecological Restoration of the Soil-Like Function in the Bauxite Residue: Natural Microbiomes Mediated Molecular Transformation of Dissolved Organic Matter
文章编号: N26082902
期刊: Environmental Science & Technology
作者: Yifan Jiang, Luyuan Chen, Hongjun Dong, Qishuang Li, Wenwei Zhao, Feng Zhu, Jun Jiang, Yufei Zhang, Shiwei Huang, Shengguo Xue
更新时间: 2026-08-29
摘要: Soilization of bauxite residues offers a scalable route for long-term carbon management and ecological restoration. However, the microbial processes that transform exogenous organic inputs into stable soil-like carbon pools remain poorly resolved. Here, we combined cross-ecosystem meta-analysis, machine-learning prediction, native synthetic community (SynCom) construction, 13C-labeled straw microcosms, field validation, Fourier transform ion cyclotron resonance mass spectrometry, and genome-resolved metagenomics to unravel microbiome-mediated carbon transformation at the dissolved organic matter (DOM) molecular scale. Our meta-analysis revealed that alkaline industrial wastes retained soil-like DOM signatures but were enriched in microbial humic- and protein-like components, indicating active yet incomplete carbon processing. Guided by these patterns, native SynCom inoculation increased 13C incorporation into total organic carbon (TOC) and dissolved organic carbon (DOC), enlarged biodegradable and adsorbable DOC fractions, and shifted DOM from recalcitrant aromatic pools toward oxygenated carbohydrate-, tannin-, and phenolic-like molecular classes. Genome-resolved analyses linked this transformation to complementary polymer degradation and nutrient-cycling functions across fungal and bacterial guilds, including enriched carbohydrate-active enzymes in straw-carbon-utilizing metagenome-assembled genomes. Null model and thermodynamic analyses further showed that microbial communities were constrained by homogeneous selection, whereas DOM molecules were diversified through variable selection and redox-dependent transformation. Field-scale validation confirmed that SynCom promoted TOC and DOC accumulation and humic-like, high-density DOM fractions under alkaline conditions. Together, these findings establish a mechanistic framework in which functional microbiomes couple plant carbon depolymerization, DOM molecular diversification, and mineral-interactive carbon stabilization, providing a microbiome-guided strategy for carbon sequestration and soilization in the bauxite residue.

240. 题目: Estimation Accuracy Obviously Increased of Soil Organic Carbon Content Based on Habitat Patches Scale Using Interpretable Machine Learning in Southwest China
文章编号: N26082901
期刊: Land Degradation & Development
作者: Wei Zhou, Jieyun Xiao, Haotian Liu, Lu Xu, Keming Wang
更新时间: 2026-08-29
摘要: Although machine learning models have been successfully applied to estimate soil organic carbon (SOC), the lack of interpretability research has resulted in the absence of mechanistic explanations for these models. Therefore, in this study, we adopted the following workflow: first, we divided the whole study area into several subregions using land cover types and habitat patch types based on cluster analysis, and then the model driving features of SOC estimation were selected using the recursive feature elimination (RFE) technique. Second, we compared the estimation accuracy and stability of three machine learning models, and explored the optimal feature combinations and model architecture. Finally, the Shapley additive interpretation (SHAP) model was introduced to interpret the selected SOC content estimation model to verify its reliability. The results showed that the divided modeling framework based on habitat patch type achieved the best performance in SOC content estimation: the maximum increase in R 2 reached 27%, and RMSE decreased by 20% (Habitat Patch 3 vs whole study area). The optimal model combination based on RFE‐RF demonstrated good estimation accuracy across the four habitat patches, with R 2 values of 0.36, 0.49, 0.62, and 0.59, and RMSE values of 22.04, 9.59, 11.67, and 14.57, respectively. Meanwhile, we analyzed the impacts of each input feature on the model prediction from both global and local perspectives. The results showed that DEM, precipitation, and air temperature were the key factors influencing the estimation of SOC content. The SHAP model successfully revealed the relationship between feature variables and SOC, effectively compensating for the limitations of the machine learning model in terms of interpretability.