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1. 题目: A Critical Review of the Contradictory Roles of Algogenic Organic Matter in Microalgae Coagulation-Flocculation: Effects of Composition, Properties, and Mechanisms
文章编号: N25071608
期刊: Water Research
作者: Lili Li, Shaozhe Cheng, Zimin Wang, Wen Zhang, Xuezhi Zhang, Haiyang Zhang
更新时间: 2025-07-16
摘要: Coagulation is a widely used pretreatment for algae-water separation, offering significant potential to enhance removal efficiency and reduce downstream processing costs. However, algogenic organic matter (AOM), a complex mixture of algae-derived organic compounds, plays contradictory roles in coagulation. Depending on its properties, AOM can either promote or deteriorate coagulation, posing challenges for process optimization. This review critically evaluated how AOM influences coagulant demand and floc characteristics, with a particular focus on its composition and properties. Evidence shows that low concentrations of high-molecular weight (MW) proteins and polysaccharides enhance coagulation through bridging mechanisms. This enhances the capture of algal cells, forming larger flocs while reducing coagulant demand. In contrast, low-MW AOM components, or excessive AOM concentrations, compete with algal cells for coagulant binding sites. This compromises coagulation efficiency, resulting in smaller flocs that exhibit reduced removal performance. Furthermore, AOM derived from different cellular compartments exerts distinct effects on algal coagulation. Soluble organic matter from intracellular (IOM) and extracellular (EOM) sources typically impair coagulation efficiency and increase coagulant consumption. In contrast, organic matter bound to the algal cell surface, specifically extracellular polymeric substances (EPS), enhances coagulation efficiency and reduces coagulant requirements. Strategies to mitigate AOM’s negative effects are discussed in detail, including optimizing coagulation parameters, developing novel coagulants to enhance flocculation, and integrating pretreatment techniques (e.g., pre-oxidation and adsorption) aimed at reducing AOM concentration or altering its characteristics. Key challenges remain, including inconsistent AOM analytical approaches and the lack of mechanistic clarity. Future research should focus on improving AOM extraction methods, identifying species- and stage-specific components, and elucidating key mechanisms underlying AOM behavior during coagulation. By linking AOM properties to its functional role, this review provides a foundation for improving algae coagulation strategies and supporting effective algal bloom control.

2. 题目: Engineered biochar amended co-composting for greenhouse gas mitigation, nitrogen conservation, and eco-efficiency assessment
文章编号: N25071607
期刊: Journal of Environmental Chemical Engineering
作者: Yanyan Huang, Xu Yang, Jianhong Li, Hailong Wang, Hongzhu Yang, Tingting Yang, Dongming Zhang, Xianghui Zhang, Wenhui Lin, Caiwang Cheng, Paramsothy Jeyakumar, Ronghua Li, Qinghuo Lin
更新时间: 2025-07-16
摘要: Greenhouse gas (GHG) emissions during aerobic composting are unavoidable, but effective additives can significantly reduce emissions. Hence, this study intended to investigate the influence of different engineered biochar, modified with various materials (MgO, NaOH, Na₂SiO₃, and HNO₃), on GHG emissions, bacterial community structure, and eco-efficiency during the co-composting process of chicken manure (CM) and bagasse. Six treatments were established, including a control (CK, a mixture of CM and bagasse), as well as treatments incorporating biochar (BC), MgO-biochar (MOBC), NaOH-biochar (SHBC), Na₂SiO₃-biochar (SSBC), and HNO₃-biochar (NABC), respectively. These treatments underwent aerobic composting for 35 days. The findings show that engineered biochar significantly reduced GHG emissions compared to CK. Specifically, MOBC achieved a substantial 66.31% reduction in cumulative NH₃ emissions, while SHBC recorded the lowest cumulative N₂O emissions. Furthermore, after composting, the MOBC treatment resulted in a significant increase of 75.72% in amino acid nitrogen and an even more pronounced increase of 1516.02% in amino sugar nitrogen. In contrast, the SSBC treatment led to increases of 66.81% in amino acid nitrogen and 253.53% in amino sugar nitrogen. The Mantel test revealed that the combination of Luteimonas, Persicitalea, and Taibaiella bacteria significantly influenced the levels of NH₄⁺-N and organic nitrogen. Regarding GHG emissions and nitrogen retention, the eco-efficiency analysis demonstrated that MOBC exhibited superior performance, suggesting its potential as an effective material for enhancing the eco-efficiency of the co-composting process.

3. 题目: Differential adsorption and degradation of organic phosphorus by different interlayer cationic clay minerals in water-sediment system
文章编号: N25071606
期刊: Journal of Environmental Chemical Engineering
作者: Fazhi Xie, Jiwei Zhou, Sainan Sun, Haibin Li, Chunshan Xu, Hongwei Liu, Zhi Yang, Bingxin Liu, Haiyang Zhang, Shan Li
更新时间: 2025-07-16
摘要: The sediment-phosphorus nexus in lakes critically mediates global carbon cycling and ecological succession. While existing studies predominantly investigate inorganic phosphorus (IP) dynamics, mechanistic insights into the sediment-water interface biogeochemical processes governing organic phosphorus (OP) fractions remain elusive. Herein, we selected montmorillonite (Mt) containing different interlayer cations (Al³⁺ and Fe³⁺, Al/Fe-Mt) as representative sediments, and phytate as the representative OP, to investigate the migration and transformation behavior of phytate at the interface of Al/Fe-Mt and water. Specifically, Al/Fe-Mt had differential adsorption and degradation effects on phytic acid, where Al-Mt could spontaneously adsorb phytic acid and remove it faster, achieving an adsorption capacity 4.4 times that of Fe-Mt. Interestingly, Mt catalyzed the phytate and caused the cleavage of phosphate ester bonds to produce small molecules, suggesting Mt in aquatic environment not only served as a primary medium for OP storage and migration, but also played a pivotal role in OP degradation and transformation via its surface structure and the chemical properties of its interlayer cations. This research offers fresh perspectives on the function of clay minerals in the phosphorus (P) cycling process in lakes, and strategies for regulating P loading in aquatic systems.

4. 题目: Deep Carbon: A Multiscale Feature‐Time Fusion Approach for Field Level Digital Soil Organic Carbon Mapping
文章编号: N25071605
期刊: European Journal of Soil Science
作者: Ayan Das, Manoj K Mishra, Somsubhra Chakraborty, Bimal K Bhattacharya, Rucha Dave, Dileep Kumar, Khushvadan Patel, Raj Setia, David C Weindorf
更新时间: 2025-07-16
摘要: Soil organic carbon (SOC) plays a key role in soil health and ecosystem services. This study introduces Deep Carbon, a modelling framework that integrates static and time‐series environmental covariates for high‐resolution SOC prediction at the field scale. Time‐series data were encoded using a stacked long short‐term memory (LSTM) neural network to extract temporal patterns of dynamic features. These encoded time‐series representations were combined with static covariates and used as inputs to train machine learning models at multiple spatial resolutions (5 km to 10 m). Individual predictions at each scale were then fused using a partial least squares regression (PLSR) model to generate SOC maps at 10 m resolution. The best accuracy was observed at 5 km scale (R2 = 0.75; RMSE = 0.30% in log scale), while the fused 10 m prediction yielded a testing R2 of 0.58 and RMSE of 0.44%. Fusion modelling identified 30 and 250 m resolutions as the most influential predictors. The approach successfully captured both high‐ and low‐frequency SOC variations and demonstrated good transferability when tested on new observations from 2022. This multi‐scale feature‐time fusion approach uses legacy ground samples and satellite data to enable scalable and accurate digital SOC mapping.

5. 题目: Accumulation mechanism of iron-bound organic carbon in soil amended with straw and biochar
文章编号: N25071604
期刊: Journal of Environmental Chemical Engineering
作者: Yafeng Han, Xin Zhang, Zongwei Wang, Zhaoyong Shi, Lirong Sun, Dayong Guo, Xugang Wang
更新时间: 2025-07-16
摘要: Iron oxides play a crucial role in regulating the stabilization of soil organic carbon. Crop straw and biochar are recognized as effective materials for improving soil quality, especially carbon storage. However, their impacts on iron-bound organic carbon (Fe-OC) remain poorly understood. To address this knowledge gap, we conducted a soil incubation experiment using wheat–maize straw and its derived biochar as exogenous carbon sources. Results showed that straw and biochar increased Fe-OC by 0.80 g·kg⁻¹ and 1.42 g·kg⁻¹, respectively, compared to the control treatment. Spectral analyses revealed that, compared with straw and the control, biochar significantly increased the values of SUVA₂₅₄, SUVA₂₆₀ and humification index (HIX) of dissolved organic carbon (DOC). These three parameters were positively correlated with Fe-OC (R = 0.99, R = 0.99, R = 0.91, P < 0.05), suggesting that the increased aromaticity, hydrophobicity and humification degree of DOC promoted Fe-OC accumulation. Furthermore, compared to straw application, biochar significantly increased fungal necromass carbon (FNC), while decreasing microbial (MNC) and bacterial necromass carbon (BNC). Random forest analyses confirmed that FNC was the most important contributor to the changes in Fe-OC (%IncMSE=6.43, P < 0.01), and Ascomycota was the only phylum exhibiting a significant positive correlation with FNC. Given that Ascomycota belongs to Y-strategy fungi and fungal necromass exhibits a greater affinity for mineral surfaces than bacterial necromass, our result suggested the proliferation of Ascomycota enhanced by biochar effectively promoted FNC accumulation, which in turn facilitated the stabilization of Fe-OC. This finding is critically important for developing effective carbon management strategies aimed at mitigating soil carbon losses and global warming.

6. 题目: Evolution of soil organic matter pools during Martian regolith terraforming, with a focus on organo-Fe (oxyhydr)oxide interactions
文章编号: N25071603
期刊: Environmental Research
作者: Beatrice Giannetta, Antonio G Caporale, Danilo Olivera de Souza, Paola Adamo, Claudio Zaccone
更新时间: 2025-07-16
摘要: The poor fertility of Martian regolith, due to its lack of organic matter (OM) and nitrogen (N), limits its suitability as a plant substrate. While compost amendment enhances short-term fertility, the mechanisms underlying long-term OM stabilization, particularly through interactions with iron (Fe) minerals, remain poorly understood. This study explores OM fractionation and Fe mineral transformations in Mojave Mars Simulant (MMS-1), both pure (R100) and amended with compost (R70C30), across two consecutive cropping cycles (potato followed by Vicia faba).Following Vicia faba cultivation, total C increased 12-fold in R70C30 (18.8 g kg^-1) compared to R100 (1.6 g kg^-1), with a 140% increase in amended and 90% in pure regolith relative to post-potato levels. Both particulate organic matter (POM) and mineral-associated organic matter (MAOM) also increased substantially: POM-C rose 7-fold, while MAOM-C increased by 947%, suggesting the formation of organo-mineral complexes. MAOM also exhibited a 447% rise in total N and the lowest C/N ratio (∼9), consistent with more microbially processed and stabilized OM.Fe speciation via Fe K-edge X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) revealed compost-driven enrichment of ferrihydrite and hematite, with distinct mineral profiles across POM and MAOM fractions. EXAFS further identified lepidocrocite and magnetite, phases undetected by XANES, highlighting the complementary role of reactive and crystalline Fe minerals in stabilizing OM in mineral matrices.These findings underscore the potential of organic amendments and leguminous crops to promote biologically functional, nutrient-rich substrates from Martian regolith simulants, offering critical insights for in situ resource utilization in space agriculture.

7. 题目: Biochar-based downflow Fixed-Bed adsorption systems for water Treatment: Process Optimization, Reusability, and Techno-Economic evaluation
文章编号: N25071602
期刊: Separation and Purification Technology
作者: Oussama Baaloudj, Fausto Langerame, Rocco Iunnissi, Gianluigi Buttiglieri, Daniele Del Buono, Samia Khadhar, Laura Scrano, Vincenzo Trotta, Monica Brienza
更新时间: 2025-07-16
摘要: Adsorption processes have emerged as promising solutions for water treatment, particularly when utilizing bioderived materials, due to their environmental sustainability. Nevertheless, a key challenge of this approach lies in the regeneration of spent materials. This study investigates the possibility of using biochar in a fixed-bed adsorption system for water treatment, focusing on its potential reuse following an environmentally friendly regeneration process and evaluating its feasibility for large-scale applications. Rapid small-scale column tests were conducted to optimize process parameters for removing sulfamethoxazole while using a high concentration to prove the concept and evaluate process efficiency. Under optimal conditions, the column maintained its operational capability after treating 33 L, achieving a saturation time of up to 130 h. The adsorption behavior was explored using kinetic models, analyzing breakthrough curves to reveal dynamic performance. The Clark model demonstrated the highest degree of fit to the data, making it a reliable tool for predicting adsorption efficiencies. The reusability of the adsorbent was evaluated through a sustainable regeneration approach, enabling effective reusability for up to 5 cycles. The applicability of the proposed treatment method was further validated on real water samples, demonstrating a significant reduction in turbidity and the concentration of detected substances in the samples. Finally, a techno-economic assessment estimated a treatment cost of €0.89/m³, supporting the economic feasibility of the approach. This research highlights the efficiency and scalability of the proposed process as a viable, cost-effective water treatment solution for large-scale applications.

8. 题目: UV aging and soil organic matter co-regulate the adsorption of organophosphate flame retardants on PVC and PS: Kinetics and mechanisms
文章编号: N25071601
期刊: Journal of Hazardous Materials
作者: Xinying Gong, Junyi Ma, Yang He, Yuxin Dong, Yuanjun Tong, Jiayu Mao, Mao Li, Dongmei Wang, Zhengjun Gong
更新时间: 2025-07-16
摘要: As widely used plastic additives, organophosphate flame retardants (OPFRs) widely coexists with microplastics (MPs) in agricultural soil, where MPs could act as carriers, increasing their environmental risk. However, the combined effects of UV aging and soil dissolved organic matter (DOM) on OPFR adsorption to MPs remains unclear. This study investigated the adsorption kinetics and mechanisms of six OPFRs on polyvinyl chloride (PVC) and polystyrene (PS). Results showed that OPFR adsorption positively correlated with their hydrophobicity (logK_ow), dominated by hydrophobic interaction and partition. Kinetic studies indicated chemisorption governed adsorption, following pseudo-second-order kinetics. Upon UV aging, PVC exhibited increased affinity for polar/medium-polar OPFRs (triethyl phosphate, tributyl phosphate, and tris(2-butoxyethyl) phosphate), attributed to hydrophilic microzones formation, while PS preferentially adsorbed non-polar OPFRs (triphenyl phosphate and tris(2-ethylhexyl) phosphate) due to increased surface roughness and abundant binding sites. For soil DOM, it competitively inhibited OPFRs adsorption via hydrogen bonding on PVC but enhanced the OPFRs adsorption on PS through π-π interactions, acting as a molecular bridge. These findings highlight the critical role of polymer type, UV aging, and DOM in regulating OPFRs fate in soil. This will enhance our understanding of the environmental risks caused by the combined pollution resulting from MPs in soil environment.

9. 题目: Characterization of chromophoric dissolved organic matter and UV-VIS spectra of Almada River blackwaters, Northeastern Brazil.
文章编号: N25071518
期刊: Environmental Monitoring and Assessment
作者: Marcelo Friederichs Landim de Souza, Carolina Santos Silva de Almeida, Daniela Mariano Lopes da Silva
更新时间: 2025-07-15
摘要: Blackwater rivers draining forested areas rich in organic soils are globally relevant because they mobilize large quantities of terrestrial dissolved organic carbon (DOC) and colored dissolved organic matter (CDOM) downstream, and export disproportionately large amounts of these compounds by drainage area to the ocean. This study investigated the optical properties and sources of CDOM in the lower portion of the Almada River watershed, located in the Eastern Brazil Basin between latitudes 14° 35'S and 14° 46'S and longitudes 39° 17'W and 39° 03'W, a region increasingly affected by deforestation. Water samples were collected during six campaigns from June 2022 (dry season) to January 2023 (rainy season) at seven sites along the river. Fluorescent CDOM (FDOM) and UV-VIS absorption spectra were analyzed to infer CDOM characteristics and composition. DOC and specific absorbance at 254 nm (SUVA254) were also estimated. Results revealed that humic-like DOM predominates throughout the basin. Lower concentrations of FDOM, DOC, and aromatic compounds downstream evidence the microbial degradation and photooxidation along the river course. Elevated FDOM and α254 near a tributary confluence point to distinct CDOM sources likely associated with a lagoon-connected channel, a large riparian wetland, and possibly a landfill leachate. Seasonal variations showed increased CDOM quantity and aromaticity during the rainy season, attributed to enhanced leaching from forest soils, despite ongoing deforestation. This work is the first study conducted to evaluate CDOM characteristics in the region and contributes to a better understanding of DOM dynamics in tropical blackwater rivers, which are recognized as major contributors to global DOC fluxes.

10. 题目: Declining soil organic matter stability over the last 150 years in coral island ecosystems revealed by chemical molecular composition
文章编号: N25071517
期刊: Catena
作者: Xianglong Xi, Shenglan Liang, Libin Wu, Liqiang Xu, Renjun Zhou, Xiaodong Liu
更新时间: 2025-07-15
摘要: Coral islands, widespread in tropical regions worldwide, have great carbon storage potential due to favorable climatic conditions for vegetation growth. However, the role of soil organic matter (SOM) in this process remains unclear. Understanding the stability of the SOM of coral islands is critical for combating climate change. Here, the sources, composition, and stability characteristics of SOM in two typical coral island soil profiles were analyzed using multi-method analyses. The stable isotope mixing model revealed a significant alteration in SOM sources from seabird guano to plant humus, reflecting the evolutionary process of island ecosystems. Results from the Fourier transform infrared spectroscopy and 13C nuclear magnetic resonance showed that the functional groups and chemical composition of SOM varied during different historical periods. The average proportion of carboxyl carbon decreased from 14.49 % to 8.30 %, while that of alkoxyl carbon increased from 43.45 % to 51.90 %. Pyrolysis analysis provided molecular fingerprints of SOM, where the average lignin content rose rapidly from 0 % to 12.31 % within 0–15 cm. This indicated a decrease in the contribution of guano to SOM, along with an increase in the contribution of plant sources. Combining the above results, structural equation modeling suggests that the guano- and plant-derived composition of SOM play a positive and unfavorable role in its stabilization. The source and composition of SOM and environmental conditions are critical determinants of soil carbon pool stability on coral islands. This study provides additional insights for thoroughly assessing SOM stability and maintaining soil carbon storage on coral islands under climate change.

11. 题目: Modified ultrafiltration membrane to improve organic matter conversion in anaerobic digestion of kitchen waste: Performance and separation mechanism
文章编号: N25071516
期刊: Journal of Environmental Chemical Engineering
作者: Boru Gao, Yiheng Xue, Shaokang Li, Jinjin Yang, Mengmeng Dou, Xiang Li
更新时间: 2025-07-15
摘要: The low organic matter conversion efficiency during the anaerobic digestion of kitchen waste is one of the major technical bottlenecks limiting its deep resource utilization. In this study, a polysulfone (PSF) membrane modified by ferric oxide hydrate (HFO)/carboxylated carbon nanotubes (CNTs) nanocomposite was applied to extract humic acid (HA) from biogas slurry produced during the anaerobic digestion of kitchen waste. The modified ultrafiltration membrane demonstrated an increase in water flux from M-0 (285.7 L m^-2 h^-1) to 489.5 (L m^-2 h^-1), with the HA rejection rate improving from 85% to 98.6%. The flux recovery ratio of M-4 increased by 30.4%, while irreversible fouling was reduced by 35.3%. The extended Derjaguin-Landau-Verwey-Overbeek theory was used to verify the fouling resistance of the membrane. Theoretical calculations revealed that electron cloud rearrangement can take place between HFO and CNTs, forming the heterojunction. The HFO/CNTs heterojunction exhibited stronger adsorption with PSF (E_ads= -1.3658 eV) compared to CNT alone (E_ads=-0.2836 eV). Additionally, the electron flow was more abundant in the HFO/CNTs/PSF system, which further promoted the dispersion of nanoparticles in the casting solution. The enhancement of the HA rejection rate was primarily attributed to the modification of the membrane surface charge characteristics. The HA extraction ultrafiltration system was constructed based on real biogas slurry. The concentration of HA increased by 15-20 times compared to its concentration in the biogas slurry through the system. This study provided an effective method for the deep resource utilization of organic matter during anaerobic digestion and a valuable insight for the practical application of ultrafiltration membranes in engineering projects.

12. 题目: Urbanization intensifies deterministic selection of pathogenic bacteria in river networks: Nitrogen-driven niche partitioning and cross-scale risk forecasting through DOM-bacteria interplay
文章编号: N25071515
期刊: Environmental Research
作者: Kun Shi, Jiafeng Zhang, Yuting Zhao, Shilei Zhou
更新时间: 2025-07-15
摘要: Urbanization modifies the composition of dissolved organic matter (DOM) and nitrogen nutrients, profoundly affecting river microbial communities. However, the mechanisms driving pathogenic and non-pathogenic bacteria remain unclear. In this study, we analyzed the river system in Shijiazhuang, a northern Chinese megacity, using high-throughput sequencing, spectroscopy, and machine learning to explore how DOM and nitrogen influence bacterial communities. Results show that downstream urban rivers have elevated nitrogen levels (TN = 8.85±2.14mg·L^-1). DOM fluorescence peaks here, showing low humification and strong autochthonous characteristics (FI > 1.9, HIX < 4). Both pathogenic (Shannon = 5.34) and non-pathogenic bacteria (Shannon = 6.43) reach maximum diversity downstream, with species replacement driving community differences. Nitrogen is the key factor increasing deterministic selection pressure on pathogenic bacteria from 1.51% upstream to 25.76% downstream. Midstream urban sewage contributes 41.39% - 89.26% to downstream pathogenic bacteria. In winter and downstream, bacterial networks become more complex. DOM explains up to 60.22% of downstream pathogenic bacterial variation. Protein-like DOM (C3) promotes summer pathogen proliferation but inhibits winter diversity. This study highlights nitrogen's role in pathogen niche differentiation and DOM's spatiotemporal regulation of bacterial interactions, providing a framework for health risk warnings in urbanized rivers.

13. 题目: Unravelling sequence-dependent molecular transformation pathways of dissolved organic matter in chemical cleaning wastewater during combined Fenton oxidation and activated carbon adsorption processes
文章编号: N25071514
期刊: Separation and Purification Technology
作者: Zhuojun Huang, Yang Wang, Qiqi Zhao, Chun Zhang, Chunyan Yang, Chuanting Zhou, Xiaodan Zhao, Zhen Zhou
更新时间: 2025-07-15
摘要: This study investigates the molecular transformations of dissolved organic matter (DOM) in industrial wastewater by combining Fenton oxidation and powdered activated carbon (PAC) adsorption processes. Industrial effluents, particularly those rich in refractory DOM, pose significant challenges for treatment and reuse. Using chemical cleaning wastewater (CCW) as a model sample, the study evaluates the impact of two coupling sequences—Fenton-PAC and PAC-Fenton—on DOM removal and transformation. The molecular-level behavior of DOM is explored using high-resolution mass spectrometry to analyze chemical changes, which reveals that each process sequence leads to distinct molecular pathways, significantly influencing the oxidation state, size, and heteroatom content of the remaining DOM. In the PAC-Fenton process, less-adsorbed substances, primarily lipids and proteins/peptides, undergo preferential mineralization or oxidation by Fenton treatment. This results in their transformation into CRAM/lignin-like compounds. In contrast, during the Fenton-PAC process, oxygen addition, dealkylation, and decarboxylation drive the depolymerization of DOM in CCW, producing smaller molecules such as amino sugars and carbohydrates. These smaller molecules exhibit weaker subsequent adsorption affinity. The findings demonstrate that the PAC-Fenton process achieves superior removal of complex DOM and incurs over 50% lower chemical costs compared to the Fenton-PAC approach, enhancing cost-efficiency. Moreover, these results provide valuable insights into optimizing industrial wastewater treatment strategies, contributing to enhanced environmental sustainability.

14. 题目: Exports of organic matter, phosphorus and nitrogen from Sichuan Basin: A critical region regulating water quality of the Upper Yangtze River, China
文章编号: N25071513
期刊: Journal of Hydrology
作者: Xiaoxiao Wang, Yanhong Wu, Mingliang Luo, Konstantina Katsanou, Jochen Wenninger, Roland Bol
更新时间: 2025-07-15
摘要: The Chinese Yangtze River is a crucial nexus for nutrient cycling between the Qinghai-Tibet Plateau and the East China Sea, but it faces significant water quality challenges due to enhanced nutrient inputs from its sub-basins. The nutrient exports from the Sichuan Basin a geographical region with intense human activities in southwest China, are foreseen to have significant impacts on the water quality of the Upper Yangtze River. To investigate the nutrient exports from the Sichuan Basin and their effects, we analysed daily data on Total Nitrogen (TN), Total Phosphorus (TP), and Chemical Oxygen Demand (COD, proxy representing organic matter) collected from 58 monitoring stations on rivers across the Sichuan Basin during 2021–2023. The results indicated that the Sichuan Basin contributed approximately 50% of the increased TN, TP, and COD in the Upper Yangtze River. The Minjiang and Qujiang Rivers rank highest in the Sichuan Basin for TN, TP exports and COD exports, respectively. Hotspots of TN and TP levels were primarily concentrated in the the western basin, while COD hotspots were mainly located in the eastern basin. The spatial analysis identified urbanization and agricultural activities as the primary drivers of nutrient distribution patterns in the Sichuan Basin. These findings underscore the need for targeted policies and strategies to enhance the controlling TN and TP losses from urban and farming areas in the rainy seasons within the catchments of the Minjiang and Tuojiang Rivers is critical for achieving sustainable water quality improvements in the Upper Yangtze River. Moving forward, the implementation of integrated pollution management strategies, supported by real-time monitoring and machine learning-based predictive modeling, is imperative in the Sichuan Basin to address the challenges of water quality deterioration driven by climate change.

15. 题目: Anion exchange membrane fouling in electrodialysis: Mechanistic insights from organic matter fractionation
文章编号: N25071512
期刊: Separation and Purification Technology
作者: Sohail Farooq, Jordan J Oak, Sampson Achagwe Antwi, Samantha Kemp, Xue Jin
更新时间: 2025-07-15
摘要: Electrodialysis (ED) is an emerging technique for nutrient recovery from anaerobic digestate; however, fouling of anion exchange membranes (AEMs) by organic matter remains a significant operational challenge. This study systematically investigated the fouling behavior of six organic fractions, obtained through sequential membrane filtration and resin adsorption, differentiated by molecular size and chemical functionality.Our results indicate that Fractions 1 and 2, comprising particulate (>0.45 µm) and large colloidal organics (>100 kDa), primarily caused external fouling, which was partially reversible, with 10–14 % of accumulated organic matter removed via electrodialysis reversal (EDR). In contrast, Fractions 3 and 6, consisting of dissolved organics (<100 kDa) and hydrophilic base/neutral components, respectively, led to severe internal fouling. Membrane resistance increased significantly from 1.6 Ω·cm² (pristine AEMs) to 15 Ω·cm² and 12 Ω·cm² after exposure to Fractions 3 and 6, respectively, resulting in nearly double the energy consumption compared to the synthetic control. Surface characterization using SEM-EDS, zeta potential, contact angle, and AFM analysis confirmed the irreversible nature of this fouling, driven by the deep infiltration of organic constituents into the membrane matrix.These findings provide clear evidence that specific organic fractions, particularly low molecular weight organic acids and hydrophilic base/neutral compounds, are primarily responsible for irreversible AEMs fouling. The results highlight the need for targeted pretreatment strategies to selectively remove these fractions prior to ED. This study advances the mechanistic understanding of dissolved organic matter (DOM)-induced membrane fouling and supports the development of more robust operational and material design strategies for sustainable nutrient recovery from complex waste streams.

16. 题目: Estimating cropland soil organic carbon stock in Erhai Lake basin: Contribution of temporal-spatial-spectral information
文章编号: N25071511
期刊: Soil and Tillage Research
作者: Xinran Ji, Bo-Hui Tang, Liang Huang, Guokun Chen, Weipeng Le, Dong Fan
更新时间: 2025-07-15
摘要: Traditional soil organic carbon (SOC) prediction methods exhibit significant uncertainty when applied to croplands in plateau lake basins, which are characterized by complex terrain, fragmented plots, and diverse cropping structures. In this study, we endeavored to overcome the limitations of traditional methods in predicting SOC content in the ecologically fragile and agriculturally vital plateau lake basins. This study effectively integrates dispersed soil data, spatial features, and temporal-spatial variations into seven categories of soil-forming factors by combining multi-source remote sensing data and a soil-pedogenic model. Furthermore, to extract the temporal-spatial-spectral (TSS) features of soil-forming factors and calculate the weights of input variables by integrating the convolutional neural networks, long short-term memory networks, and attention mechanism (CNN-LSTM_A), thereby enhancing the predictive accuracy and interpretability of SOC content. Finally, based on two periods of measured topsoil (0–20 cm) sample data, we constructed a precise estimation framework for interannual variations in cropland SOC stocks in the plateau lake basin. The results showed that CNN-LSTM_A outperformed six comparison models in both prediction accuracy and temporal transferability: reducing the RMSEmean and MAEmean by 1.6796–1.9558 g kg−1 and 0.7835–1.2400 g kg−1, increasing the R2mean, RPIQmean, and CCCmean by 0.0970–0.1273, 0.3863–0.5778, and 0.0773–0.1100, respectively. Additionally, the results confirmed that long-term crop growth information indirectly reflects the SOC accumulation process, contributing to improved prediction accuracy. From 2007–2016, the spatial heterogeneity of cropland SOC content in the Erhai Lake basin was jointly driven by vegetation and topography, with vegetation being the more influential factor. Higher SOC content was observed in regions on the western and northern sides of Erhai Lake, exhibiting certain temporal dynamics. During this period, cropland SOC content exhibited an overall increasing trend, with significant increases concentrated in the northern basin. However, due to a reduction in cropland area, total SOC stocks showed a decreasing trend (4.366 Tg C and 4.136 Tg C). Specifically, 0.475 Tg C was indirectly lost due to land use changes, while areas of unchanged cropland directly contributed a gain of 0.245 Tg C due to increasing SOC content. This research not only provides critical data support for ecological management and sustainable agricultural development in the Erhai Lake basin but also offers scientific backing for ecological protection and broader-scale carbon cycling studies in other ecologically fragile areas.

17. 题目: Effects of cultivation time on soil physical, chemical properties, soil organic carbon, total nitrogen stocks and dioxide carbon emission in Southeast of Chad
文章编号: N25071510
期刊: Catena
作者: Mouaromba Wavel, Mabicka Obame Rolf Gael, Musadji Neil-Yohan, Adoum Abdramane, Ngon Ngon Gilbert François, Etame Jacques
更新时间: 2025-07-15
摘要: This study aimed to examine the effects of agricultural activities on soil physico-chemical, SOC, TN stocks and CO2 emissions as a function of cultivation duration. The study was carried out in southeastern Chad, focusing on three localities near the city of Am-Timan: Darasna (North-East), Madina and Goz-Mabile (West). These sites have been intensively cultivated for flood recession sorghum production under glyphosate use for 25 35 and 50 years, respectively. Six soil profiles were collected and a total of 144 samples were obrained-36 per site. Soil samples were collected randomly from each plot at 0–10 cm, 10–20 cm, 20–30 cm, 30–40 cm, 40–50 cm and 50–60 cm in triplicate per experimental unit. The results indicated that soil pH in the study area was slightly alkaline and influenced by cultivation duration, with the highest pH observed after 25 years of cultivation. Additionnally, soil bulk density and texture were affected by the duration of agricultural practices. The highest bulk density was recorded after 25 years of cultivation, while lower bulk densities were observed after 35 and 50 years of farming cropping, highlighting the impact of cultivation time on soil compactionr. A decline in SOC and TN stocks was evident with more than 25 years of cultivation, along with an increase in CO2 emissions, particularly in the topsoil (0–20 cm) and subsurface (20–40 cm). Reducing cultivation duration may enhance soil fertility by improving soil physicochemical, as well as soil organic matter, ultimately contributing to increase crop yields and climate change mitigation.

18. 题目: Impact of seasonal hydrologic cycle-induced organic phosphorus processing on phosphorus dynamics in groundwater
文章编号: N25071509
期刊: Journal of Hydrology
作者: Binyu Wang, Yao Du, Jiawen Xu, Hao Tian, Yiqun Gan, Yanxin Wang
更新时间: 2025-07-15
摘要: The accumulation of geogenic phosphorus (P) in groundwater is a pressing global environmental issue. Although the degradation of P-containing dissolved organic matter (P-DOM) significantly influences geogenic P enrichment, the seasonal variations of P-DOM and their effects on geogenic P dynamics remain unclear. To address this knowledge gap, we analyzed the optical and molecular characteristics of DOM and P-DOM, coupled with hydrogeochemistry and carbon isotopes across dry, normal, and wet seasons, in a geogenic P-affected aquifer system within the central Yangtze Plain. The results showed that the concentrations of total dissolved phosphorus (TDP) and dissolved inorgnaic phosphorus (DIP) in groundwater progressively increased from the dry season to wet seasons. During the dry season, the humification degree of DOM was higher, with DIP enrichment mainly associated with the transformation of highly unsaturated compounds and polyphenols. In the normal season, enhanced leaching introduced some highly unsaturated compounds into groundwater, during which a significant negative correlation was observed between DIP concentrations and highly unsaturated compounds and polycyclic aromatics. During the wet season, the freshness of DOM markedly increased, while the percentage of P-DOM reaches its minimum. At this stage, DIP enrichment was mainly associated with highly unsaturated compounds. Rainfall-induced leaching and sediment disturbance from lake backflow introduced aromatic compounds into the groundwater. Simultaneously, the intensified interaction between surface water and groundwater allowed lake water to bring oxidizing agents into groundwater, thereby altering environment conditions conducive to P-DOM degradation and ultimately increasing groundwater P concentrations. Additionally, compounds positively correlated with DIP concentration showed increased H/C and decreased O/C ratios across seasonal variations, confirming greater P-DOM degradation during this period. This study provides a new temporal perspective on the geochemical behavior of P in groundwater, emphasizing the significant influence of seasonal variations on P cycling.

19. 题目: Nitrogen-induced soil acidification mitigates the negative effects of nitrogen addition on SOC stability
文章编号: N25071508
期刊: Soil and Tillage Research
作者: Xinsheng Zhang, Shibing Jia, Chengming You, Hongwei Xu, Yaling Yuan, Jiao Li, Sining Liu, Bo Tan, Zhenfeng Xu, Jordi Sardans, Josep Peñuelas
更新时间: 2025-07-15
摘要: While nitrogen (N) deposition is a well-established driver of soil organic carbon (SOC) stability, quantitative syntheses assessing its global-scale impacts remain surprisingly limited. This study conducted a meta-analysis of 4418 observations from 131 independent studies to investigate how SOC, particulate organic carbon (POC), and mineral-associated organic carbon (MAOC) response to N addition. Our findings showed that N addition increased SOC (6.53 %), POC (12.59 %) and MAOC (3.45 %) pools. Nevertheless, the POC:SOC ratio increased by 5.46 %, whereas the MAOC:SOC ratio decreased by 2.2 %, indicating that N addition reduced SOC stability. Under N addition, soil acidification was categorized into three levels based on the magnitude of soil pH decline: non-acidified [≥ 0], mildly acidified [-0.5–0] and severely acidified [≤ -0.5]. Soil acidification inhibited the positive responses of SOC and POC to N addition. With increasing acidification, both SOC and POC declined progressively. In contrast, Soil acidification generally promoted the accumulation effect of N addition on MAOC, as the 4.21 % increase in MAOC under mild acidification exceeded the 0.25 % loss under severe acidification. Furthermore, the MAOC:SOC ratio steadily increased under N-addition treatments, indicating that N-induced soil acidification contributed to SOC stability. Overall, our study demonstrated that N-induced soil acidification mitigated the negative effects of N addition on SOC stability by regulating the POC and MAOC response to N addition. These findings underscore the crucial role of soil acidification in regulating SOC dynamics under N addition and offer new insights into the interactions between soil C and N.

20. 题目: Microbial electrotrophs-driven molecular transformations of dissolved organic matter in paddy soil
文章编号: N25071507
期刊: Journal of Environmental Management
作者: Rong Tang, Xiaoshan Luo, Wenjie He, Xixi Cai, Lingyan Huang, Lihua Zhou, Yong Yuan
更新时间: 2025-07-15
摘要: Microbial electrotrophs are key players in biogeochemical cycles, but the impact of electrotrophic communities on the diverse chemical composition and properties of dissolved organic matter (DOM) molecules in paddy soils has not been comprehensively explored. Herein, we investigated the response of DOM molecules in paddy soil-based microcosms to electrotrophic communities using microbial electrosynthesis systems (MESs), high-resolution mass spectrometry, and genome-centric metagenomics techniques. Compared to the open-circuit control, the closed-circuit system exhibited a 2.6-fold increase in dissolved organic carbon concentration after 120 days of incubation in the MESs, with aromatic and tannin molecular abundances rising by 3.5-fold and 4.4-fold, respectively. These results indicate that electrotrophic activity enhances both the structural complexity and aromatization (humification degree) of soil DOM. Functional annotation revealed significant enrichment of the reductive tricarboxylic acid (rTCA) cycle and Calvin–Benson–Bassham (CBB) cycle, demonstrating active CO2 assimilation by electrotrophs into complex organic compounds. Electrotrophic genera such as Pseudomonas, Hyphomicrobium, Phenylobacterium, Achromobacter, Geobacter, Anaeromyxobacter, and Magnetospirillum were substantially enriched under the closed-circuit conditions, with relative abundances increasing from 0.02-0.72 % to 1.65–13.68 %. These microbes likely facilitated DOM stabilization by coupling extracellular electron uptake with CO2 fixation, thereby transforming labile organic carbon into more stable molecular structures. These findings elucidate the impact of electrotrophic bacteria in regulating the DOM transformation, providing a deeper understanding of the transformation mechanisms of DOM in paddy soils.