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1. 题目: Regulatory effects of nano-carbon on poplar growth and rhizosphere soil organic carbon accumulation
文章编号: N25042310
期刊: Environmental Research
作者: Xiaomei Huo, Mengjie He, Jun Qiao, Jianguo Zhao, Bin Yang
更新时间: 2025-04-23
摘要: The positive effects of nano-carbon on plant growth and soil C sequestration within the rhizosphere have been widely recognized. Nevertheless, information is seriously deficient in understanding the underlying mechanisms based on microbial communities and carbon cycle functional genes. Here, metagenomic sequencing was employed to explore different responses of poplar seedling growth and organic carbon fractions to nano-carbon fertilizers at concentrations of 0 ml/kg (CK), 5 ml/kg (NC-5), 10 ml/kg (NC-10) and 20 ml/kg (NC-20). We observed that, after 120 days of nano-carbon fertilizers treatments, the growth indexes (height and biomass) of poplar were significantly increased by 53-173 %, and C fractions in the rhizosphere soil were significantly increased by 1.6-8.2 % with the NC-5 treatment having a greater impact on organic carbon components than the NC-10 and NC-20 treatments. Compared to CK, the additions of nano-carbon fertilizers significantly increased the content of total nitrogen (TN), nitrate nitrogen (NN), and available potassium (AK) in the rhizosphere soil and decreased the pH, and improved stochastic processes in microbial communities, which elevates the abundance of microbes involved in carbon fixation (e.g., Proteobacteria, Actinobacteria) and carbon-cycling genes. In addition, network complexity and stability of microbes were significantly enhanced by nano-carbon treatments. Structural equation model indicated that microbial community assembly processes directly alter rhizosphere SOC accumulation. Carbon functional genes influenced by microbial structure have positive effects on biomass of poplar and SOC contents. Our observations provide key evidence for evaluating how nano-carbon fertilizers may influence functional changes in C cycle that are mediated by microbial synergy.

2. 题目: Silicon-enriched rice straw biochar and silicon fertilizer mitigate rice straighthead disease by reducing dimethylarsinic acid accumulation
文章编号: N25042309
期刊: Plant and Soil
作者: Yang Yang, Zhong Tang, AXiang Gao, Chuan Chen, Peng Wang, Fang-Jie Zhao
更新时间: 2025-04-23
摘要:

Background and aims

Rice is prone to accumulating both inorganic arsenic (iAs) and organic arsenic species, such as dimethylarsinic acid (DMA). DMA is the primary causative agent of rice straighthead disease, a physiological disorder that leads to substantial yield losses. In this study, we investigated whether rice straw-derived biochar with different silicon (Si) contents and Si fertilizer can alleviate rice straighthead disease and decrease DMA accumulation in rice grains.

Methods

Low- and high-Si biochars were produced from straw of a low-silica rice mutant lsi2 and its wild type (WT), respectively, by carbonization at a temperature of 450 °C. Pot experiments were conducted to investigate the effects of rice straw-derived biochar and a powdered Si fertilizer on As speciation in soil porewater at different rice growth stages and DMA accumulation in rice grains.

Results

The Si content of the high- and low-Si biochars differed substantially (127.4 g kg⁻¹ for WT and 47.8 g kg⁻¹ for lsi2 biochar), with approximately 18% Si bioavailability following biochar application. Both biochar and Si fertilizer application alleviated straighthead disease and decreased DMA levels in grain by 24–58.2%, with the high-Si biochar outperforming other treatments.

Conclusions

The beneficial effects of the biochar on mitigating straighthead disease were primarily attributed to their Si content and the capacity to maintain prolonged Si availability in soil porewater. Additionally, supplementation with Si during the booting stage of rice proved particularly effective in maintaining Si availability, reducing DMA uptake, and alleviating straighthead disease.

3. 题目: Formation Mechanisms of Carcinogenic N-nitrosamines from Dissolved Organic Matter Derived from Nitrogen-containing Microplastics During Chloramine Disinfection
文章编号: N25042308
期刊: Water Research
作者: Run Zhou, Kecheng Zhu, Zhuo Gao, Xuemin Feng, Qian Hu, Lingyan Zhu
更新时间: 2025-04-23
摘要: The high occurrence of microplastics (MPs) in water treatment facilities may complicate the source-control of disinfection by-products. Herein, we reported that the carcinogenic N-nitrosamines, such as N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA), were generated during monochloramine disinfection of water in which nitrogen-containing microplastics (N-MPs, such as polyamide and polyacrylonitrile) were present. The precursors of NDMA and NDEA were mainly derived from the dissolved organic matter released from N-MPs (N-MP-DOM), which were characteristic of a significantly higher proportion of polar and non-cationic fractions, favouring the N-nitrosamine formation. The results of excitation-emission-matrix spectra and orbitrap-mass spectrometry indicated that the polar components were mainly CHON and highly hydrogen-saturated molecules (H/C ≥ 1.5) (such as protein-like substrates), which are potential precursors of N-nitrosamines. Further mass difference network analysis revealed that the reactions of amine and nitro/nitroso groups in the precursors made predominant contribution to the generation of N-nitrosamines. Two potent NDMA precursors bearing a (CH₃)₂N-R structure were identified based on the diagnostic fragments (e.g., 45.0578 Da and m/z 58.0651) and in silico fragmentation tool (MetFrag2.2) in MS² spectra. Our findings provide valuable insights into understanding the potential risks of N-MPs due to monochloramine disinfection in water treatment systems.

4. 题目: The photoactivity of complexation of DOM and Fe(Ⅱ)/Mn(Ⅱ) in aquatic system: Implication on the photodegradation of MCLR
文章编号: N25042307
期刊: Journal of Environmental Chemical Engineering
作者: Haishuo Wang, Xinke Tian, Zhichun Li, Jie Zhang, Shiyin Li, Heyong Huang
更新时间: 2025-04-23
摘要: Lake eutrophication leads to the excessive proliferation of cyanobacteria in aquatic environments, resulting in microcystin-LR (MCLR) concentrations exceeding regulatory limits. The associated environmental risks and health concerns attract widespread attention. As one of the most active chemical substances in aquatic environments, dissolved organic matter (DOM) plays a critical role in the phototransformation of MCLR. In environments where Fe(II) and Mn(II) coexist, the phototransformation process of MCLR may be influenced. Among fulvic acid (FA), humic acid (HA), cyanobacteria-derived DOM (CDOM), and reed leaf-derived DOM (RDOM), FA has the highest apparent reaction rate constant for MCLR at 0.03567 h^-1. Using isopropanol, furfuryl alcohol, and sorbic acid as quenchers, the contributions of different photochemically produced reactive intermediates(PPRIs) to MCLR photodegradation follow the order: ³DOM⁎ > ·OH > ¹O₂. As pH increases, changes in the conformation and charge distribution of DOM and MCLR suppress MCLR photodegradation. The addition of Fe(II) or Mn(II) enhances the photodegradation of MCLR by DOM. Electron paramagnetic resonance tests and radical quenching experiments indicate that the introduction of Fe(II)/Mn(II) increases ·OH production. The enhanced ·OH promotes MCLR photodegradation more effectively than the suppression caused by Fe(II)/Mn(II) quenching of ³DOM⁎. Product analysis reveals that demethylation, hydroxylation, decarbonylation, decarboxylation, denitration, and bond cleavage are the main pathways of MCLR photodegradation. These findings provide valuable insights into the migration and transformation of MCLR in complex environments, contributing to a deeper understanding of the fate of pollutants in natural water systems, particularly in the presence of metal ions.

5. 题目: Plant functional type control on soil microbial activity and carbon source utilization in permafrost peatland
文章编号: N25042306
期刊: Plant and Soil
作者: Jing Xue, Yifei Zhang, Shujie Wang, Yu Du, Dongxu Wang, Hao Zhang, Yanyu Song, Xianwei Wang, Xiaoxin Sun
更新时间: 2025-04-23
摘要:

Background and aims

Climate warming can lead to changes in plant functional types (PFTs) in permafrost peatlands, which can subsequently affect soil properties and microbial functional structures. Although the effects of PFTs changes on soil microorganisms in various ecosystems have been documented, these effects are not well understood in permafrost peatlands.

Methods

This study investigated the impact of removing different PFTs (sedges, evergreen shrubs, deciduous shrubs, and mosses) on soil properties and microbial functional structures (microbial activity, microbial diversity, and carbon source utilization) in a permafrost peatland.

Results

Variations in PFTs lead to changes in soil properties and microbial functional structures. Removal of shrubs and mosses increased soil dissolved organic carbon (DOC) content by 26% and inorganic nitrogen content by 28%, the soil microbial activity and diversity were significantly enhanced, and microbes preferred amino acids and carboxylic acids as carbon sources compared to the natural control (N). In contrast, the moss treatment (M) with shrubs and sedge removed had 30% lower soil DOC and 50% lower inorganic nitrogen content, as well as a significant reduction in microbial activity and diversity, with microorganisms preferring to utilize polymers as a carbon source.

Conclusion

These results indicate that peatland microorganisms are sensitive to changes in PFTs over short time scales, with a particularly rapid response to specific plant functional groups such as sedges. These findings highlight the critical role of PFTs as drivers of microbial functional structures and suggest that future vascular plant expansion may alter peatland microbial functional structures and carbon cycling in the context of climate change.

6. 题目: Molecular Insights into Dissolved Organic Matter Post Electrokinetic-Persulfate Treatment: Heteroatom Induced Resistance
文章编号: N25042305
期刊: Journal of Hazardous Materials
作者: Xinxu Niu, Jian Liu, Shaohua Chen, Bin Jiang, Jianzhi Huang
更新时间: 2025-04-23
摘要: The application of electrokinetic-enhanced in situ chemical oxidation remediation of contaminated sediments has attracted increasing attention. However, the molecular changes in dissolved organic matter (DOM) during these remediation processes remain unexplored. To address the gap, we explored the molecular transformation of DOM subjected to electrokinetic (EK)-persulfate treatment. The findings revealed that DOM transitioned from a reduced to an oxidized state, marked by the removal of low O/C molecules and the formation of high O/C molecules. Heteroatom-containing molecules accumulated and constituted the dominant fraction among the resistant molecules post-treatment. N-containing and Cl-containing molecules displayed elevated N/C and Cl/C ratios during the treatment, decomposing into smaller and nitrogen-rich or Cl-rich molecules, while S-containing molecules exhibited a decrease in S/O ratios. Oxygen addition reaction and dealkyl group reaction were identified as the two most common transformation pathways, contributing to the increased oxidation and resistance of DOM molecules. This study deepens our understanding of DOM transformation using EK-persulfate treatment and aids in assessing the potential risks associated with resistant molecules in its practical application.

7. 题目: Modified slow sand filter amended magnetic corncob biochar and zero-valent iron for arsenic removal from drinking water
文章编号: N25042303
期刊: Environmental Earth Sciences
作者: Taimoor Khan, Qasim Ali, Imdad Ullah, Shams Ali Baig, Dilawar Farhan Shams, Xinhua Xu, Muhammad Danish
更新时间: 2025-04-23
摘要:

The toxicity of arsenic (As) in drinking water poses a significant risk to public health, and its effective removal is essential to reduce the associated risks. Modified slow sand filter (SSF) has emerged as a promising decentralized water treatment method in developing countries due to its user friendliness, economic viability, and environment-friendly properties. The present study investigated the total arsenic removal efficiency and turbidity reduction in laboratory-scale SSF columns designed for a 60-day filtration period. For this purpose, SSF columns were modified with magnetic corncob biochar (MCCB) and zero-valent iron (ZVI) layers in different ratios. The characterization tests, including Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), and X-ray Diffraction (XRD), were conducted before and after the filtration. Results revealed that the MCCB surface was porous with a honeycomb-like structure before adsorption, containing cave-like holes favourable for arsenic removal. Similarly, the ZVI surface exhibited a tabular and thread structure. The EDS results confirmed the presence of Fe in the MCCB and ZVI, indicating the magnetic properties of both adsorbents. Notably, maximum As removal efficiency of 80% was observed in SSF(b) with a 10 cm MCCB layer after 60 days, whereas SSF(d) with a 10 cm ZVI layer achieved 99% within just 10 days of filtration. In addition, SSF columns containing ZVI layers achieved a maximum turbidity removal of 98% and 99% after 10 days of filtration, while SSF(b) with a 10 cm MCCB layer reached a turbidity removal of 99.9% after 60 days. Statistical analyses indicated that these differences were significant (p < 0.05), demonstrating the superior efficacy of the ZVI-based SSF for arsenic removal and the strong performance of MCCB in turbidity reduction. Overall, SSF-amended MCCB and ZVI demonstrated effective removal of As and turbidity. The study suggests that the designed SSFs are durable and user-friendly filter made of locally avaible low-cost materials for water filtration.

8. 题目: Cropping History and Cropland Abandonment Period Influenced Levels of Soil Organic Carbon, Distribution of Aggregates and Aggregate Associated Carbon
文章编号: N25042302
期刊: Land Degradation & Development
作者: Sinesihle Mcengwa, Siphamandla Nyambo, Vusi Erick Mbanjwa, Dimpho Elvis Elephant
更新时间: 2025-04-23
摘要: Knowledge gaps remain regarding soil organic carbon (SOC) storage and aggregate dynamics under varying cropland abandonment periods, particularly within the context of degraded and low-SOC soils. This study aimed to assess the influence of cropping history and the period of cropland abandonment period on SOC, aggregate distribution, and aggregate associated carbon in the Eastern Cape, South Africa. Two abandoned cropland sites, namely 2 LUC (abandoned since 2021) and 6 LUC (abandoned since 2017), were examined. Soil samples were collected at depth intervals of 0–10 cm, 10–20 cm, and 20–30 cm. The samples were analyzed for soil texture, pH, organic carbon, humic and fulvic acids, exchangeable Ca, Mg, and K, wet and dry aggregate distribution, mean weight diameter (MWD), and aggregate associated organic carbon. Dry and water stable microaggregates plus individual particles dominated in 2 LUC, while 6 LUC showed an even distribution of large and small macroaggregates, along with microaggregates plus individual particles. Wet and dry MWD were significantly higher in 6 LUC across all depths. Macroaggregate associated organic carbon did not differ significantly between the sites and depths, whereas microaggregate associated organic carbon was consistent between sites but decreased with depth from 0–10 cm to 10–20 cm. The results highlight the complex interaction between soil structure, aggregate stability, and carbon content, suggesting that a combination of factors such as cropping history, soil disturbance, and biological activity shape aggregate characteristics, in addition to the effects of SOC. Additionally, the duration of cropland abandonment plays a key role in overcoming the legacy effects of prior land use.

9. 题目: Improved identification of chlorinated disinfection byproducts by the sequential elution and absorption mode
文章编号: N25042301
期刊: Journal of Hazardous Materials
作者: Rong Qin, Yiming Feng, Shasha Zhuo, Qing-Long Fu
更新时间: 2025-04-23
摘要: Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) has been extensively employed to characterize the chemodiversty of dissolved organic matter (DOM) including chlorinated disinfection byproducts (Cl_n-DBPs). However, little is known about the combined effects of the sequential solid phase extraction (SPE) and absorption mode of Fourier transform data processing on the identification of Cl_n-DBPs. In this study, the identification of Cl_n-DBPs by the sequential SPE extraction and absorption mode were systematically compared using a typical swimming pool water. The sequential SPE extraction was more effective in extracting DOM molecules including Cl_n-DBPs than the traditional extraction, yielding 48.2 % ± 2.1 % and 87.3 % ± 3.8 % more DOM molecules and Cl_n-DBPs molecules, respectively. Moreover, a total of 274 nitrogenous Cl_n-DBPs were identified by the sequential SPE extraction with 80 more than that by the traditional SPE. The absorption mode improved the resolution and the signal-to-noise values of DOM peaks by factors of 1.87–1.98 and 1.52–1.60, respectively. The number of resolved Cl-related mass doublets within 2 mDa mass difference in the absorption mode was 537 more than that in the magnitude mode. Overall, the combination of sequential elution and absorption modes facilitated the detection of more molecules of DOM and Cl_n-DBPs compared to traditional SPE in magnitude mode, with an increase of 92.7 % ± 2.1 % and 121.7 % ± 5.6 %, respectively. These results have highlighted the great potential of the sequential elution combined with absorption mode in improving the identification of Cl_n-DBPs and their precursors, facilitating the application of FT-ICR MS in the nontargeted analysis of emerging contaminants including Cl_n-DBPs at the molecular level.

10. 题目: Urbanization enhances soil nitrogen mineralization mainly by increasing particulate organic nitrogen fractions in urban park greenspaces: A case study in Hangzhou, China
文章编号: N25042219
期刊: Applied Soil Ecology
作者: Bo Fan, Yuye Shen, Yan Wang, Liming Yin, Kumuduni Niroshika Palansooriya, Yongfu Li, Bing Yu, Scott X Chang, Yanjiang Cai
更新时间: 2025-04-22
摘要: In addition to the direct input of inorganic nitrogen (N), the supply of plant-available N driven by soil organic N mineralization is crucial for the development of urban greenspaces, which are essential components of urban ecosystems. Soil N mineralization may vary with urbanization, but the responses of soil N mineralization to different urbanization intensities remain controversial. In this study, we investigated the responses of urban park soil (planted with trees, shrubs or grasses) N mineralization to different urbanization intensities (low, medium and high) in Hangzhou, China. To further evaluate the relative importance of soil organic N fractions in explaining variations in N mineralization, we analyzed the responses of soil particulate organic N (PON) and mineral-associated organic N (MAON) to different urbanization intensities, as well as their relationships with N mineralization. Our results indicated that soil N mineralization increased with increasing urbanization intensity, likely due to increases in soil organic carbon concentration, clay content, microbial biomass and activity under high urbanization intensity. Notably, compared to soil MAON, the increase in soil PON induced by urbanization was more pronounced, and its relationship with soil N mineralization was stronger. Furthermore, soil N mineralization and its relationships with soil organic N fractions varied substantially among different vegetation types. These findings suggest that researchers and urban planners should evaluate the N supply mineralized from soil organic N fractions, particularly PON fractions, to optimize N and vegetation management strategies in urban greenspaces under different urbanization intensities.

11. 题目: Microbial effect on soil organic carbon accumulation and stabilization is lithology-depend in subtropical coniferous forest
文章编号: N25042218
期刊: Applied Soil Ecology
作者: Tao Yang, Liang Dong, Haoran Zhang, Chenghao Zheng, Jinxing Zhou, Xiawei Peng
更新时间: 2025-04-22
摘要: Lithology plays a crucial role in controlling the soil carbon (C) pool in forest ecosystems. The dynamics of soil organic C (SOC) are significantly influenced by the composition and function of the soil microbial community. However, the mechanisms by which lithology influences SOC and the involvement of microbes in this process remain unclear. To assess both the accrual and stability of SOC, we analyzed its content and physical composition by fractionating it into labile particulate organic C (POC) and stable mineral-associated organic C (MAOC). The study was conducted in two representative plantation coniferous forests developed on karst (limestone) and non-karst (shale) soils, with the aim of elucidating potential microbial regulatory mechanisms underlying lithology-mediated differences in SOC dynamics. Our findings revealed that SOC concentration was significantly higher in karst soils compared to non-karst soils at both depths, primarily due to the greater accumulation of MAOC, while lithology had a different effect on POC between topsoil and subsoil. Interestingly, the ratio of MAOC to POC was higher in karst soils compared to non-karst forests only in subsoils. These results imply the crucial role of lithology on SOC accrual and stability in coniferous forests. Soil nutrients stoichiometry, pH and exchangeable calcium ions (Ca2+) have exerted influence over microbial community composition, whereas microbial biodiversity and life history strategies only affected by soil nutrients. Additionally, structural equation modeling analyses revealed that lithology exerts a stronger influence on SOC than tree species, as lithology affects soil nutrient availability, thereby indirectly regulating the microbial impact on SOC accumulation. Nonetheless, both tree species and lithology significantly influence Ca2+, which indirectly promote SOC accumulation by enhancing the stability of SOC pool. Collectively, our study highlights the key role of lithology in SOC stability and accrual, providing a lithology-dependent linkage between microbial communities and the soil C pool.

12. 题目: Distribution and Source Identification of Sediment Organic Carbon of the Coastal Wetlands Around Bohai Sea
文章编号: N25042217
期刊: Wetlands
作者: Xiaoyao Li, Mengyi Wang, Wanxin Tian, Gang Xu, Zhaona Ding
更新时间: 2025-04-22
摘要:

Coastal wetlands are significant global carbon (C) sinks, but the characteristics and sources of organic carbon (OC) are far from understood due to the difficulties in assessing the different sources of the OC. In this study, sediments from eight reed wetlands around the Bohai Sea were collected. Sediment organic carbon (SOC), total nitrogen (TN) and the stable carbon/nitrogen isotope compositions (δ¹³C, δ¹⁵N) were analyzed to quantify the contributions of different sources to SOC. The results indicated that the SOC content ranged from 0.15% to 4.90%, with an average of 1.16%. The δ¹³C ranged from - 27.10‰ to - 21.70‰ (mean: - 24.76‰) and the δ¹⁵N varied from 1.19‰ to 6.58‰ (mean: 3.16‰), suggesting that the SOC were predominantly derived from reed detritus. Three major sources of the SOC were identified: reed detritus, terrestrial and marine OC. Using the IsoSource model, the reed detritus contribution were calculated as 67.5%, 43.5%, and 51.8% to the SOC of the Liaodong Bay wetlands (LDBW), Bohai Bay wetland (BHBW) and Laizhou Bay wetland (LZBW), respectively. Terrestrial OC accounted for an average of 16.5%, 33.9%, and 40.2% of the SOC in LDBW, BHBW, and LZBW, respectively. In contrast, marine OC contributed 16.0%, 22.7%, and 8.1% to the SOC in the same regions. For LZBW and LDBW, the reed detritus was the main source of SOC of the restored wetland whereas the terrestrial or marine derived OC became increasingly significant in tidal wetlands. Our results suggested that vegetation played a crucial role in carbon sequestration of coastal wetlands, therefore the wetland restoration project for vegetation improvement management need to be strengthened in the future. These findings provide a scientific basis for future monitoring of the organic carbon of the coastal wetlands.

13. 题目: Multi-Phase mobilization and degradation pathway of natural organic matter within alluvial-lacustrine aquifer sediments
文章编号: N25042216
期刊: Journal of Hydrology
作者: Wenkai Qiu, Yao Du, Wenhui Liu, Xinyu Liu, Yamin Deng, Teng Ma, Yanxin Wang
更新时间: 2025-04-22
摘要: Alluvial-lacustrine sediments are crucial organic matter pools in the subsurface, fueling biogeochemical processes in aquifers through the release of dissolved organic matter (DOM). However, little is known about the detailed mobilization and degradation pathways of organic matter from sediments to groundwater. Here, we examined porewater bridging sediments and groundwater and characterized the fluorescence properties and molecular composition of DOM in porewater with varying binding strengths to sediments. Results showed that bound water DOM primarily contained polycyclic aromatics, polyphenols, and highly unsaturated compounds with high O/C ratios and humification indices. Free water DOM, by contrast, was rich in aliphatic compounds with high H/C ratios and biological indices. Unique molecular formulae analysis revealed that in bound water, CHO + nN polyphenolic compounds were consumed, and highly unsaturated CHO + 2 N compounds were produced; in free water, highly unsaturated CHO + 2 N compounds were consumed, and CHO + 1 N aliphatic compounds were produced. This molecular fractionation of organic matter is likely controlled by abiotic diffusion and adsorption as well as by biotic microbial activity, with the former dominating in bound water and the latter in free water. This may relate to the stable double-layer structure in bound water and the increased exposure to electron acceptors in free water. Together, these dual mechanisms produce a high proportion (>50 %) of biodegradable DOM in free water, potentially explaining the geogenic enrichment of ammonium in local aquifers. Our results highlight the strong influence of local mobilization and degradation processes on the molecular characteristics of DOM, bearing significant environmental implications for the evolution of groundwater quality.

14. 题目: Mechanisms of chemical polymers and microbial residues in affecting organic matter stabilization under varying carbon/nitrogen ratios during composting
文章编号: N25042215
期刊: Chemical Engineering Journal
作者: Penghui Jia, Yimei Huang, Xiangyu Wang, Zhaolong Zhu, Yanxing Dou, Qian Huang, Simin Zha, Aowei Wang
更新时间: 2025-04-22
摘要: The stability of organic matter in compost is crucial for its high-value utilization, but the mechanisms of composting conditions affecting the stabilization remain unclear. Chemical polymers and microbial residues represent two critical components of the stable organic carbon pool, with the carbon/nitrogen (C/N) ratio being a key composting condition. In this 40-day composting study with C/N ratios of 25, 30, and 35, chemical polymers were characterized spectroscopically, while four microbial residue types—bacterial necromass C, fungal necromass C, extracellular polymeric substances (EPS)-protein, and EPS-polysaccharides—were quantitatively analyzed. Humification index (HI) was used to assess organic matter stability, and key microbial groups, enzyme activities, and small organic molecules were also investigated. Compared to a C/N ratio of 35, HI increased by 46.1% at a C/N ratio of 25, chemical polymers were significantly enhanced, EPS-protein and EPS-polysaccharides content increased by 59.2% and 14.3%, respectively, while bacterial necromass C content decreased by 48.0%. The contribution of chemical polymers on HI was more pronounced at a C/N ratio of 25, whereas the contribution of microbial residues diminished. C/N variation regulated HI mainly by affecting chemical polymers and bacterial necromass. The C/N ratio of 25 stimulated the growth of r-strategy microorganisms, increasing hydrolase activity and small organic molecules, which indirectly promoted chemical polymers synthesis. However, intensified microbial competition for resources resulted in bacterial necromass consumption, thereby directly reducing its content and contribution. These findings provide a new perspective for understanding the mechanism in the process of organic stabilization in composting regulated by C/N ratio.

15. 题目: Synthesizing ZIF-8 functionalized biochar by in situ reuse of residual Zn from chemical activation for enhanced tetracycline hydrochloride adsorption removal
文章编号: N25042214
期刊: Journal of Environmental Chemical Engineering
作者: Jianying Liu, Qian Zeng, Yao Chen, Zhongde Dai, Wenju Jiang, Lu Yao, Junfeng Zheng, Dengrong Sun, Yanping Wu, Lin Yang
更新时间: 2025-04-22
摘要: In this study, an innovative method for synthesizing ZIF-8 functionalized biochar (ZIF-8@BC) by repurposing residual Zn of chemical activation was proposed. The approach simultaneously achieves biochar functionalization and high-value reuse of waste activators. The results revealed that ZIF-8 was successfully synthesized using the residual Zn (ZnCl₂ & ZnO). The integration of ZIF-8 resulted in a highly porous structure in ZIF-8@BC, increasing its specific surface area and exponentially enhancing tetracycline hydrochloride (TCH) adsorption capacity. Under optimized conditions, the ZIF-8@BC3-2-500/2 exhibited a high surface area of 1200 m²/g and a pore volume of 0.85 cm³/g, coupled with the rich-N containing functional groups, helping it achieve an equilibrium adsorption capacity of TCH at 177.63 mg/g. The Langmuir model described the adsorption behavior of TCH better, yielding a maximum capacity of 288.85 mg/g. Mechanistic analysis indicated chemisorption driven by π-π interactions and hydrogen bonding, with a multi-stage process involving film diffusion, intraparticle diffusion, and equilibrium. Furthermore, ZIF-8@BC3-2-500/2 demonstrated broad applicability, adsorbing methylene blue (598.5 mg/g) and Cu²⁺ (241.2 mg/g) efficiently, highlighting its potential for multi-pollutant wastewater treatment.

16. 题目: Chemodiversity and molecular traits of dissolved organic matter driven by cascade reservoirs regulations in the upper Yangtze River
文章编号: N25042213
期刊: Journal of Environmental Management
作者: Lunhui Lu, Yiwei Guan, Wenjuan Ouyang, Yan Xiao, Yufei Bao, Dianchang Wang, Zhe Li
更新时间: 2025-04-22
摘要: Dissolved organic matter (DOM) plays a fundamental role in biogeochemical cycles within riverine ecosystems. However, the construction and impoundment of dams disrupt the natural biophysical gradients in rivers, potentially leading to alterations and turnover of DOM compositions. This research investigated the composition and chemodiversity of DOM in the cascade reservoirs along the upper Yangtze River. Our findings reveal that DOM in the cascade reservoirs are predominantly composed of lignin-like, lipid-like, and protein-like compounds. The DOM chemodiversity exhibited a significant decrease during the flood season, but recovered during the dry season. Additionally, a general decline in DOM chemodiversity was observed along the longitudinal gradient in the cascade reservoirs. The molecular traits of DOM results indicated high bioavailability and lability of DOM molecules during the flood season. A random forest analysis identified physicochemical indicators as the most important factor influencing DOM chemodiversity. During the flood season, the selected variables were mostly strongly correlated with DOM molecular traits and categories. Specifically, Qin and Qout showed significant negative correlations with easily degradable compounds such as carbohydrates and lipids, as well as with molecular traits. Conversely, during the dry season, few physicochemical indicators and hydrological parameters show significant correlations with proteins and aromatic compounds. Structural equation model further demonstrated that hydrological parameters exert a strong positive influence on DOM molecular categories. This study provides a foundational framework for further evaluation cascade damming effects on DOM biogeochemical processes.

17. 题目: MnSO4-modified woodchip biochar “dual fixation” mechanism: functional group-electron synergistic stabilization of heavy metals and carbon structure
文章编号: N25042212
期刊: Journal of Environmental Chemical Engineering
作者: Jianhua Li, Gaoyuan Gu, Jianing Zhang, Yuanfei Wang, Chong Peng, Yun Li, Shuyi Yang, E Tao
更新时间: 2025-04-22
摘要: To solve the problem of soil carbon loss due to mineralization of soil organic carbon caused by heavy metal pollution. In this study, MnSO₄-modified biochar prepared by impregnation pyrolysis successfully reduced the mobility of copper (Cu) and lead (Pb) in the soil, inhibited the mineralization of soil organic carbon, and thus reduced CO₂ emissions. The loading of MnSO₄ and MnS particles promoted the carbon sequestration of biochar from 44% to 53%, synchronizing the stabilized carbon content of the material with the soil organic carbon content. Combined with experimental and DFT calculations, the loading of MnSO₄ and MnS increased the active sites on the surface of the biochar with a significant increase in the energy gap. The -COOH and S^2- groups were combined with Cu and Pb, and the residual contents of Cu and Pb were increased from 9% and 8% to 33% and 23%, respectively. Furthermore, the mineralization rate of soil organic carbon decreased from 0.5 mg‧g^-1‧d^-1 and 0.48 mg‧g^-1‧d^-1 to 0.38 mg‧g^-1‧d^-1 and 0.35 mg‧g^-1‧d^-1, respectively. The binding of MSC with Cu and Pb reduced carbon activity near the reaction site, prevented the oxidative degradation of the carbon skeleton by forming a stable residue state complex with Cu and Pb, and achieved the synergistic effect of heavy metal stabilization and carbon sequestration simultaneously. The MnSO₄-modified biochar of the present study provides new insights into the synergistic stabilization of heavy metals and carbon sequestration.

18. 题目: Stability of Reactive Iron-Bound Organic Carbon During Sulfidization of Iron Oxides: Insights From Methane-Seep Sediments
文章编号: N25042211
期刊: Geophysical Research Letters
作者: Yu Hu, Kai Li, Johan C Faust, Jörn Peckmann, Dong Zhang, Linying Chen, Qianyong Liang, Duofu Chen, Dong Feng
更新时间: 2025-04-22
摘要: The association of organic carbon (OC) to reactive iron oxides (Fe_R), forming OC-Fe_R complexes, represents a significant OC sink in marine sediments. However, the impact of diagenetic processes, such as sulfate reduction and iron sulfide formation, on the stability of OC-Fe_R in marine sediments remains poorly understood. Here, we compare sulfidic sediments from three cores taken at methane seeps with a non-sulfidic sediment record from a nearby site. Our results show that an overall 6.3% decrease in OC-Fe_R is associated with a 42% reduction in Fe_R during the transformation from iron oxides to iron sulfides, suggesting that OC-Fe_R is resistant to sulfidization. We observed highly ¹³C-depleted OC-Fe_R in the sulfidic sediments, likely due to the interaction between OC and Fe_R during anaerobic oxidation of methane. Our findings highlight the stability of OC-Fe_R in natural sulfidic sediments, offering new insights into the role of OC-Fe_R in continental margin sediments.

19. 题目: The components and aromaticity of dissolved organic matter derived from aquatic plants determine the CO2 and CH4 emission potential
文章编号: N25042210
期刊: Water Research
作者: Kun Wang, Wanchang Ding, Xiaosong Yang, Weiwei Lü, Haoyu Ren, Xia Jiang
更新时间: 2025-04-22
摘要: Lakes are integral to the carbon cycle through the processing of dissolved organic matter (DOM). However, the specific contributions of various aquatic plants to carbon emissions during their decomposition remain inadequately understood. In this study, decomposition experiments were performed on three aquatic plants—algae, Phragmites australis (PA), and Potamogeton crispus L. (PC)—using advanced techniques, including FT-ICR-MS and metagenomics, to investigate the mechanisms of carbon dioxide (CO₂) and methane (CH₄) emissions. The results indicate that algae exhibit a substantial potential for CO₂ emissions, with emissions reaching up to 2,193 μmol·g^–1. Conversely, PA contributes the highest CH₄ emissions, reaching up to 2,397 μmol·g^–1. Factors such as the protein-like content and aromaticity of DOM molecules significantly influence emission levels. DOM with lower aromaticity undergoes easier decomposition in the first 6 days, leading to increased CO₂ production. Elevated C/N and C/P ratios in plants enhance the abundance of methanogenic bacteria and genes. Surplus carbon will be mineralized under anaerobic conditions, giving rise to mineralization of organics to CH₄. These findings elucidate the mechanisms underlying CO₂ and CH₄ emissions during the decomposition of different aquatic plants and provide valuable insights for lake water environment management.

20. 题目: Biochar suppresses Clubroot disease in Chinese cabbage by improving soil nutrient conditions and recruiting beneficial microorganisms
文章编号: N25042209
期刊: Applied Soil Ecology
作者: Jisheng Wang, Sichun Li, Huimiao Yin, Muhammad Riaz, Xinwei Liu, Mengyang Zhang
更新时间: 2025-04-22
摘要: Clubroot, a fungal disease transmitted through soil, can significantly reduce both the productivity and quality of Chinese cabbage. Biochar is regarded as an effective soil amendment for enhancing stress resistance in plants, but there are still few studies on its use for the prevention and control of cabbage clubroot. This study involved field experiments to evaluate the effects of different biochar application rates on the soil microenvironment, cabbage quality, and clubroot incidence. Rice straw was pyrolyzed at 400 °C to produce biochar, which was then applied at rates of 0 t/hm2 (CK), 24 t/hm2 (BC1), 48 t/hm2 (BC2), and 96 t/hm2 (BC3). The results showed that biochar effectively inhibited the development of clubroot in Chinese cabbage. Moreover, when the application rate of biochar was 96 t/hm2, the disease suppression rate reached 90 %. The 96 t/hm2 application rate not only enhanced the health of cabbage but also significantly increased the soluble protein and vitamin C contents by 56.5 % and 337.6 %, respectively. Concurrently, the soil pH rose by 1.1 units, indicating a positive shift in soil conditions. Furthermore, biochar application led to a consequential notable increase of 97.9 %–452.0 % in soil nutrient content. In addition, qPCR and amplicon sequencing techniques revealed that biochar significantly reduced the abundance of Plasmodiophora brassicae, the causative agent of clubroot disease, while simultaneously promoting the recruitment of potentially beneficial microbes, including Sphingomonas, Gaiella, Penicillium, and Olpidium. In summary, biochar enhances the resistance of Chinese cabbage to clubroot disease by improving soil pH, nutrientavailability, and promoting beneficial microorganisms. These findings offer valuable insights into the role of biochar in enhancing agricultural productivity and sustainability.