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61. 题目: Stabilization of dredged sediments containing humic acid with nano-modified ordinary Portland cement-sulphoaluminate cement
文章编号: N25010707
期刊: Journal of Soils and Sediments
作者: Desheng Li, Lei Lang, Meng Dong, Zhen Hu
更新时间: 2025-01-07
摘要:

Purpose

Ordinary Portland cement-sulphoaluminate cement (CSC) with mass ratio of 1:1 was used to stabilize dredged sediments (DS) containing humic acid (HA), and nano-modification was adopted to further improve the stabilization efficiency. A series of strength and microstructural tests were conducted to clarify the strength development and associated micro-mechanisms of CSC-stabilized DS (CSDS).

Methods

Three types of nanoparticles including nano-SiO₂ (NS), nano-MgO (NM), and nano-Al₂O₃ (NA) were incorporated as nano-modifiers in single and composite forms. Unconfined compressive strength (UCS) tests were conducted to investigate the strength development of nano-modified CSDS under effects of CSC content, HA content, water content and nano-modification. X-ray diffraction (XRD), thermogravimetry (TG), and scanning electron microscopy (SEM) tests were also performed to clarify the micro-mechanisms affecting the strength development of nano-modified CSDS.

Results

Incorporating suitable nanoparticles can significantly improve the strength-gaining properties of CSDS, and optimum dosages of single NS, NM, and NA were respectively 4%, 5%, and 4%. Compared with single nano-modification, the composite nano-modifier NS/NA with mass ratio of 3:7 exhibited the best efficiency. Adding 4% optimum NS/NA can improve the 7d-, 28d-, and 90d-UCS of CSDS by 25.2%, 31.4%, and 31.4%, respectively. The cementitious products C-S-H gel, C-A-H gel, and ettringite were mainly responsible for the strength development of nano-modified CSDS.

Conclusions

Nano-modification is an effective approach to improve the stabilization efficiency of CSC on DS containing HA, and composite nano-modifier NS/NA with mass ratio of 3:7 exhibited best efficiency.

62. 题目: The response of soil organic carbon sequestration to organic materials addition in saline-alkali soil: from the perspective of soil aggregate structure and organic carbon component
文章编号: N25010706
期刊: Plant and Soil
作者: Liuyu Zhang, Mengmeng Chen, Yutong Zong, Zeqiang Sun, Yuyi Li, Xiaodong Ding, Shirong Zhang
更新时间: 2025-01-07
摘要:

Background and aims

Promoting soil organic carbon (SOC) sequestration is the key to improving soil quality. Adding organic materials is a common practice to promote SOC sequestration. However, the mechanism of SOC sequestration in saline-alkali soil with different organic materials addition is still unclear.

Methods

Field experiment was conducted: (1) Control, no fertilization; (2) NPK, only mineral fertilizer addition; (3) OF, NPK plus 2000 kg C ha^-1 addition of organic fertilizer; (4) MS, NPK plus 2000 kg C ha^-1 addition of maize straw.

Results

Compared with NPK treatment, the mean weight diameter (MWD) in OF and MS treatments was increased by 23.08% and 11.54%, respectively, which was due to the reduction of exchangeable sodium saturation percentage. Exchangeable calcium and magnesium were positively correlated with MWD, and their contents in OF treatment were 6.89-32.05% higher than those in MS treatment. Meanwhile, MWD was positively correlated with SOC stock, and small macro-aggregates contributed the most to SOC. Compared with NPK treatment, the ratio of mineral-associated organic carbon to particular organic carbon in MS and OF treatments were increased by 34.06% and 80.88%, respectively. Exchangeable magnesium and calcium could bind with polysaccharide, carboxyl and phenol to form complex under organic materials addition. Hence, SOC stock in OF and MS treatments was increased by 14.18% and 6.38% compared to NPK treatment, respectively.

Conclusion

The addition of organic materials improved the stability of aggregate structure and SOC pool in saline-alkali soil, thereby promoting SOC sequestration, in which organic fertilizer showed better effect.

Graphical

63. 题目: Unleashing the potential of biomass-doped sludge biochar: Promotion of persulfate activation by biochar-derived dissolved organic matter
文章编号: N25010705
期刊: Separation and Purification Technology
作者: Yuxuan Yang, Yubo Cui, Ke Zhao, Hongjie Sun, Wanjun Zhang, Peijing Kuang, Xu Ma, Kongyun Zhu, Kedong Ma
更新时间: 2025-01-07
摘要: This study explores the enhancement of sludge-derived biochar (SBC) performance through a synergistic coupling of zinc chloride (ZnCl₂) activation (ZnAC) and biomass doping for advanced oxidation processes (AOPs). ZnAC significantly increased the specific surface area (SSA), porosity, and functional group (FG) diversity of SBC, leading to improved adsorption and degradation capabilities for pollutants. Biomass doping further enhanced pollutant removal efficiency, with varying effects based on biomass type, as demonstrated by the order CM@SBC > CS@SBC > CH@SBC. The results reveal that ZnAC modifies biochar’s microstructure, increasing porosity while hindering graphite carbon formation, whereas biomass doping promotes graphitization and diversifies FGs. Key functional groups, such as quinones, were identified as critical for persulfate (PS) activation, catalyzing the production of reactive oxygen species (ROS) like 1O₂. Furthermore, biochar-derived dissolved organic matter (BDOM) played a pivotal role, with its quinone-rich structure and high content of pyrrole and pyridine nitrogen enhancing PS activation. The catalytic mechanism confirmed that 1O₂ is generated primarily through quinone group catalysis and ̇O₂^- conversion, highlighting the role of BDOM in pollutant degradation. This research provides a comprehensive understanding of biochar modification mechanisms and offers insights into optimizing its application in sustainable environmental remediation.

64. 题目: Biochar-mediated remediation of low-density polyethylene microplastic-polluted soil-plant systems: Role of phosphorus and protist community responses
文章编号: N25010704
期刊: Journal of Hazardous Materials
作者: Qi-Lu Zhuang, Hai-Yan Yuan, Min Sun, Huan-Guang Deng, Eric Fru Zama, Bao-Xian Tao, Bao-Hua Zhang
更新时间: 2025-01-07
摘要: While the prevalent utilization of plastic products has enabled social advancement, the concomitant microplastics (MPs) pollution presents a serious threat to environmental security and public health. Protists, as regulators of soil microorganisms, are also capable of responding most rapidly to changes in the soil environment. The amelioration mechanisms of biochar in the soil-plant systems polluted by low-density polyethylene microplastics (LDPE-MPs) and the response of protist communities in the soil-plant systems polluted by MPs remain unclear. In this field experiment, the same concentration of biochar (2%) was applied to remediate different concentrations (1% and 10%) of LDPE-MPs pollution in cherry radish soil. The main results indicate that, when compared with the treatment of applying biochar to address high-level LDPE-MPs polluted soil (BP2), the remediation of low-level LDPE-MPs polluted soil by biochar (BP1) led to a 62.02% reduction in soil available phosphorus. Meanwhile, the abundance of phoD and the activity of alkaline phosphatase increased by 127.75% and 22.57% respectively. Moreover, in contrast to BP2, the root biomass and phosphorus content of cherry radish in BP1 increased by 52.80% and 42.86% respectively. For protist communities, their structure, niche width, and assembly were altered. The interaction between biochar and LDPE-MPs influenced phosphorus cycling, and protists were closely associated with these processes. Therefore, soil phosphorus cycling indicators and protist community may be important indicators for biochar amelioration on soil MPs pollution. The study highlights the importance of considering these factors for better farmland management in the context of MPs pollution, which is significant for sustainable agriculture and environmental protection.

65. 题目: Micro-biochar coated on coarse fiber by in situ growth for efficient indoor PM2.5 and ozone removal
文章编号: N25010703
期刊: Separation and Purification Technology
作者: Junchao Xu, Yiming Xie, Wuwang Han, Qingdong Yao, Li Lv, Yunfei Zhang, Huaqiang Chu, Fuping Qian
更新时间: 2025-01-07
摘要: Indoor particulate matter, with an aerodynamic diameter smaller than 2.5 µm, known as PM2.5, significantly imperils human health, necessitating effective removal strategies. However, conventional air purification technologies often struggle to achieve a balance between high efficiency and low resistance. Employing coarse fibers with electrostatic-assisted air filtration (EAA) technology offers a potential solution for this problem. However, the inferior dielectric properties of coarse fibers lead to low electric field strength after polarization. In this work, we introduce a novel approach to address this issue by coating a biochar thin layer in situ on polyethylene terephthalate (PET) to fabricate composite fibers, resulting in a material with a relative dielectric constant as high as 3.45. The simulation results indicate that this coated micro biochar layer significantly enhances the effective electric field within the PET fiber. When applied in an EAA filtration system, the composite material achieved a remarkable removal efficiency of 98.65 % for 0.3 μm particles at a flow rate of 0.4 m/s, and 91.42 % for ozone. Furthermore, the biochar layer’s thickness, at approximately 2 μm, constitutes only 10^-3 of the inter-fiber gap in PET, maintaining the composite material’s resistance within the range of 8 to 54 Pa across various velocities. Consequently, the composite quality factor (CQF) of the material significantly exceeds that of PET fibers. In conclusion, the composite fiber material presents a highly promising avenue for achieving efficient, low-resistance indoor air purification.

66. 题目: Sustainability transformation of coal chemical wastewater treatment through carbon capture processes
文章编号: N25010702
期刊: Journal of Environmental Chemical Engineering
作者: Yang Li, Chunrong Wang, Rongfei Feng, Jianming Huang, Yu Wang, Hui Li
更新时间: 2025-01-07
摘要: Organic matter in wastewater is a high-energy material that can be recovered and used for energy generation. As such, carbon capture technologies are proposed as an important means to increase energy recovery and help wastewater treatment systems become energy self-sufficient or even carbon neutral. However traditional coal chemical wastewater treatment has become a major bottleneck limiting the sustainable development of the new coal chemical industry, which needs to be upgraded and transformed to achieve the goal of energy self-sufficiency. This article presented a summary and analyzed of the characteristics of organic matter in typical coal chemical wastewater, a detailed review of carbon capture technologies that have been maturely applied to municipal wastewater, to established a link between coal chemical wastewater and carbon capture technologies. A chemically enhanced-high load membrane bioreactor was proposed as a means of efficiently recovering organic material from coal chemical wastewater. Furthermore, mass balance calculations and economic analyses were conducted on organics in order to evaluate the viability of this methodology. The aim of this study is to provide valuable reference material for coal chemical wastewater treatment to achieve energy self-sufficiency.

67. 题目: Coastal redox shifts over the past 167 years and preservation of total organic carbon and total nitrogen
文章编号: N25010701
期刊: Marine Pollution Bulletin
作者: Yang-Guang Gu, Hai-Song Li, Hong Su, Richard W Jordan, Rui-Ze Liang, Shi-Jun Jiang
更新时间: 2025-01-07
摘要: This study reconstructs the environmental history of Xincun Lagoon over the past 167 years using sediment core XCW, employing Cu/Zn as a proxy for redox changes. Time-series analysis of Cu/Zn ratios reveals a significant decline (linear regression slope = −0.00082, p < 0.001; Mann-Kendall τ = −0.601, p < 0.001), indicating a steady reduction in redox potential and oxygen levels throughout the study period. This trend is attributed to anthropogenic activities, eutrophication, and climate-induced changes. Additionally, correlation analysis highlights strong linear relationships between Cu/Zn ratios and both total organic carbon (TOC) and total nitrogen (TN), emphasizing the role of redox conditions in the preservation of TOC and TN in lagoon sediments. The study also identifies a shift in organic matter sources from predominantly marine to a mix of marine and terrestrial inputs after 1990. These findings offer new insights into the interplay between redox dynamics and sedimentary processes, advancing our understanding of the lagoon's environmental evolution.

68. 题目: Magnetic nanoparticle modified moss Biochar: A novel solution for effective removal of enrofloxacin from aquaculture water
文章编号: N25010622
期刊: Journal of Environmental Management
作者: Ruonan Yang, Zhonghua Li, Chompoonuch Pitakrattanawong, Lei Zhu, Bingzhi Li, Longxiang Fang, Limin Fan, Chao Song, Shunlong Meng
更新时间: 2025-01-06
摘要: The presence of residual antibiotics in water constitutes a potential threat to aquatic environments. Therefore, designing environmentally friendly and efficient biochar adsorbents is crucial. Aquaculture by-product moss (bryophyte) was transformed into biochar, which can eliminate antibiotics from wastewater through adsorption. This study successfully fabricated moss biochar (BC) and magnetically modified moss biochar (MBC), and explored their adsorption performance for enrofloxacin (ENR). Characterization analyses revealed that the specific surface area, total pore volume, and the quantity of functional groups of the MBC were significantly larger than those of the BC. The Langmuir isotherm model suggests that the maximum adsorption capacities of BC and MBC for ENR are 7.24 mg g⁻1 and 11.62 mg g⁻1. The adsorption process conforms to a pseudo-second-order kinetic model. Studies carried out at different temperatures disclose the spontaneous and endothermic thermodynamic characteristics of the system. Under neutral conditions, the adsorption efficiency attains its peak. The existence of various coexisting ions in water exerts a negligible influence on the adsorption process; furthermore, when the concentration of humic acid (HA) ranges from 0 to 20 mg/L, the removal rate remains above 90%. In actual water samples, the antibiotic removal rate can be as high as 96.84%. After three cycles of reuse, the structure of MBC remains unchanged while maintaining a high removal efficiency. The primary mechanisms for antibiotic adsorption by MBC involve electrostatic interactions, hydrophobic interactions, pore-filling effects, hydrogen bonding, and π-π interactions. This reusable magnetic moss biochar provides a promising research direction for effectively eliminating antibiotics from water sources.

69. 题目: Density functional theory calculation for understanding the roles of biochar in immobilizing exchangeable Al3 + and enhancing soil quality in acidic soils
文章编号: N25010621
期刊: Ecotoxicology and Environmental Safety
作者: Debo He, Xinyi Liu, Dongni Hu, Ping Lei, Jinbo Zhang, Zhixin Dong, Bo Zhu
更新时间: 2025-01-06
摘要: Soil acidification poses a significant threat to agricultural productivity and ecological balance. While lime is a common remedy, it can have limitations, including nutrient deficiencies and potential soil compaction. Therefore, exploring alternative and sustainable amendments is crucial. This study investigated the efficacy of biochar as a substitute for lime in reducing soil acidification and improving soil quality. Through incubation experiments, we compared the effects of biochar and lime on soil properties. Additionally, we employed density functional theory (DFT) calculations to elucidate the mechanisms underlying biochar's ability to immobilize exchangeable Al3+. Furthermore, we conducted 15N double-labeled incubation experiments to examine the impact of biochar on soil nitrogen (N) transformation in acidic conditions. Our results indicated that biochar was as effective as lime in enhancing soil quality and mitigating acidification. Soils developed from the Jurassic Shaximiao Formation (J2s) purple mudstone with 3 % biochar addition exhibited a 31.15 % and 17.43 % increase in total N compared to soils treated with 0.1 % and 0.2 % lime, respectively. Similarly, soils developed from the Cretaceous Jiaguan Formation (K2j) purplish red sandstone with 1 % and 3 % biochar addition showed a 38.75 % and 64.30 % increase in soil organic carbon compared to soils treated with 0.2 % lime. DFT calculations revealed that biochar's functional groups exhibited a stronger affinity for immobilizing exchangeable Al3+ than other soil cations. This preferential adsorption was attributed to the stronger interaction and higher bond dissociation energy between biochar functional groups and Al3+. These findings collectively highlight the potential of biochar as a sustainable and effective amendment to reduce Al toxicity in acidic soils, thereby promoting soil quality and sustainable agricultural and ecological practices.

70. 题目: Short-term warming supports mineral-associated carbon accrual in abandoned croplands
文章编号: N25010620
期刊: Nature Communications
作者: Zhenrui Zhang, Hui Gao, Xiaoxia Gao, Shurui Huang, Shuli Niu, Emanuele Lugato, Xinghui Xia
更新时间: 2025-01-06
摘要:

Effective soil organic carbon (SOC) management can mitigate the impact of climate warming. However, the response of different SOC fractions to warming in abandoned croplands remains unclear. Here, categorizing SOC into particulate and mineral-associated organic carbon (POC and MAOC) with physical fractionation, we investigate the responses of POC and MAOC content and temperature sensitivity (Q₁₀) to warming through a 3-year in situ warming experiment (+1.6 °C) in abandoned croplands across 12 sites in China (latitude: 22.33–46.58°N). Our results indicate that POC content remains unchanged while MAOC content significantly increases under warming. POC and MAOC content changes are mainly influenced by root biomass and microbial necromass carbon changes, respectively. The Q₁₀ of MAOC is significantly lower than that of POC regardless of the warming or control treatment, suggesting that MAOC represents the most persistent and least vulnerable carbon fraction within SOC. Collectively, the sequestration of stable soil carbon can be enhanced in abandoned croplands under short-term warming.

71. 题目: Molecular fractionation during coprecipitation of dissolved black carbon with Fe(III): Preferential carbon sequestration for redox active molecules
文章编号: N25010619
期刊: Chemical Engineering Journal
作者: Leiye Sun, Tianming Wang, Bo Li, Jiayan Wu, Linqing Liu, Jieyu Liu, Sheng Liu, Pingxiao Wu, Yihao Li, Zhi Dang, Nengwu Zhu
更新时间: 2025-01-06
摘要: Coprecipitation with Fe(III) is a vital geochemical process for controlling mineral–water distribution of dissolved black carbon (DBC), which inevitably causes molecular fractionation. Nevertheless, the effect of molecular fractionation induced by coprecipitation on redox activity of DBC remain unclear. Here, we explore the molecular composition of DBC before and after coprecipitation with Fe(III) using Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS), and examine the change of redox activity using electrochemical method. Based on our results, coprecipitation with Fe(III) has the potential to sequester DBC in Fe minerals by forming DBC-ferrihydrite complexes. However, the sequestration was incomplete (no more than 50%). DBC components with high molecular weight, O content, unsaturation, and aromaticity (e.g., condensed aromatics, tannins, and lignins) were preferentially sequestered during coprecipitation, whereas nonaromatic components (e.g., lipids, proteins/aliphatics, and carbohydrates) were retained in the aqueous phase, indicating that molecular fractionation occurred between the coprecipitate products and the aqueous phase. Coprecipitation at a lower initial C/Fe molar ratio resulted in more significant fractionation phenomenon and a higher fractionation degree. Moreover, coprecipitation with Fe(III) caused a downward tendency in the redox activity of the residual DBC, and this decline was positively correlated with the fractionation degree. The DBC molecules that determine redox activity were also observed to be preferentially sequestered during coprecipitation. Hence, carbon sequestration caused through coprecipitation of DBC with Fe(III) exhibited preferential selectivity for the redox active components. These results promote our understanding of the effects of coprecipitation process with Fe(III) on the biogeochemical features, behaviors, and implications of DBC in the environment.

72. 题目: Heating-Induced Redox Property Dynamics of Peat Soil Dissolved Organic Matter in a Simulated Peat Fire: Electron Exchange Capacity and Molecular Characteristics
文章编号: N25010618
期刊: Environmental Science & Technology
作者: Peijie Yang, Ying Wang, Xiangwei Tian, Yifan Cui, Tao Jiang, Guangliang Liu, Yanwei Liu, Yingying Guo, Ligang Hu, Jianbo Shi, Qinghua Zhang, Yongguang Yin, Yong Cai, Guibin Jiang
更新时间: 2025-01-06
摘要: Peatlands store one-third of the world’s soil organic carbon. Globally increased fires altered peat soil organic matter chemistry, yet the redox property and molecular dynamics of peat-dissolved organic matter (PDOM) during fires remain poorly characterized, limiting our understanding of postfire biogeochemical processes. Clarifying these dynamic changes is essential for effective peatland fire management. This study demonstrates temperature-dependent dynamic changes in the electron exchange capacity (EEC) of PDOM by simulating peat soil burning, significantly affecting microbial iron reduction. At low fire temperatures (200–250 °C), the EEC remains constant by releasing more phenolic moieties to enhance the electron-donating capacity (EDC). Higher temperatures (500 °C) diminish 90% of the EEC by consuming phenolic–quinone moieties. Pyrolytic PDOM (pyPDOM) contributes to 40% of the EEC of peat soil, with this contribution declining at higher temperatures. Phenolic–quinone moieties remain the primary redox-active moieties in pyPDOM. Fourier transform ion cyclotron resonance mass spectrometry analysis shows that postfire EDC depends more on phenolic types than abundance, with monophenol-like molecules (C < 12) being more significant than polyphenol-like (C ≥ 12). Quinone moieties in pyPDOM are associated with high-oxygen condensed aromatics, and their depletion reduces the electron-accepting capacity, weakening its electron shuttle effect in microbial iron reduction. Our findings enhance the understanding of the changes in PDOM redox properties during fires.

73. 题目: Time-resolved fluorescence measurements of dissolved organic matter (DOM) as a function of environmental parameters in estuarine waters
文章编号: N25010617
期刊: Environmental Science and Pollution Research
作者: Warren J de Bruyn, Dhivya Manickam, Aaron W Harrison, Catherine D Clark
更新时间: 2025-01-06
摘要:

Fluorescent lifetimes of dissolved organic matter (DOM) and associated physicochemical parameters were measured over 14 months in an estuary in Southern California, USA. Measurements were made on 77 samples from sites near the inlet, mid-estuary, and outlet to maximize the range of physicochemical variables. Time-resolved fluorescence data were well fit to a triexponential model with an intermediate lifetime component (τ₁: 1 to 5 ns), a long lifetime component (τ₂: 2 to 15 ns), and a short lifetime component (τ₃: < 1 ns). The amplitude of the short-lived component dominated all measurements (60–70%). However, fractional contributions to steady-state fluorescence were dominated by the intermediate and long-lived components at most wavelengths. Lifetimes varied as a function of both excitation and emission wavelength suggesting structural differences in DOM fluorophores. Lifetimes decreased from the estuary inlet to the outlet and were positively correlated with absorbance and DOC concentrations and negatively correlated with salinity and spectral slope. Quenching experiments with halide ions demonstrated that fluorophores are quenched by heavy ions and that different fluorophores are quenched at different rates. However, concentrations of ions in seawater are not high enough for quenching to completely account for observed lifetime changes across the estuary. The observed variation in lifetimes between sites is instead primarily attributed to structural changes associated with DOM processing. Higher lifetimes are associated with less processed material at the inlet site.

74. 题目: An efficient fungi-biochar-based system for advancing sustainable management of combined pollution
文章编号: N25010616
期刊: Environmental Pollution
作者: Ying Xia, Minghui Deng, Tao Zhang, Junjun Yu, Xinda Lin
更新时间: 2025-01-06
摘要: Heavy metal (HM) contamination poses significant global environmental threats, impacting ecosystems, public health, and sustainable development. Fungi, as eco-friendly alternatives to chemical treatments, have the potential to reduce HM bioavailability in contaminated soils while promoting plant growth. However, current fungal remediation methods face limitations in efficiency, long-term effectiveness, and the ability to address combined contamination, particularly with naturally occurring strains. Herein, we developed a Trichoderma reesei-Laccase (LAC)-Biochar coupling system (TLBS), based on the structural and electrostatic analyses of LAC’s metal-chelated active site (T1 Cu), for the sustainable remediation of combined pollutants, including HMs. In the TLBS, genetically engineered T. reesei produces a mutated LAC with enhanced binding capability for HMs (Ni and Cd). The TLBS enables high-efficiency remediation through three steps. First, lignin-derived biochar serves as both a supportive carrier and an inducer, initiating LAC expression. Second, natural mediators are released due to the interaction between biochar and T. reesei, and LAC is activated by environmental HMs and natural mediators. Finally, TLBS achieved significant reductions in the available concentrations of Ni (93.63%) and Cd (89.68%) and efficiently remediated multiple organic pollutants (71.41–96.79%), including antibiotics and pesticides. Furthermore, the synergistic interaction among TLBS components ensures long-term remediation effects in environments rich in agricultural biomass, making it ideal for eco-friendly farming practices. This in situ amendment strategy, utilizing only green, biodegradable lignocellulosic wastes and environmentally friendly fungi, offers new pathways for the sustainable management of combined contamination and the improvement of human health.

75. 题目: Microbial mediation of soil organic carbon fractions and its feedback to long-term climate change
文章编号: N25010615
期刊: Plant and Soil
作者: Xinqi SiMa, Rui Fang, Zhenhua Yu, Yansheng Li, Xiaojing Hu, Haidong Gu, Caixian Tang, Judong Liu, Junjie Liu, Xiaobing Liu, Guanghua Wang, Ashley Franks, Kuide Yin, Jian Jin
更新时间: 2025-01-06
摘要:

Aims

Understanding the long-term effects of elevated atmospheric CO₂ (eCO₂) and warming on soil organic carbon (SOC), along with the microbial mechanisms involved, is important for predicting SOC stability in the context of future climate change.

Methods

Open-top chambers were used to simulate an increase in the atmospheric CO₂ concentration to 700 ppm (eCO₂) and an air temperature of 2 °C above the ambient temperature (warming) in a six-year experiment to examine the effects of eCO₂ and warming on the SOC fractions and bacterial community diversity. Maize plants were grown in four major farming soils, namely, Phaeozem, Kastanozem, Fluvisol and Acrisol.

Results

Six years of eCO₂ did not increase the SOC concentration in any soil but altered the distribution of the SOC fractions. In comparison, eCO₂ and warming decreased fine particulate organic C (fPOC) but increased the mineral-associated organic C (MOC) concentrations in Phaeozem and Kastanozem. In comparison, eCO₂ and warming significantly decreased the MOC in Fluvisol and tended to increase it in Acrisol. For Phaeozem, Kastanozem and Acrisol, fPOC was negatively correlated with MOC (p < 0.05). Warming altered the bacterial community composition in Kastanozem, Acrisol and Fluvisol. The increased abundance of Aquicella in Fluvisol under eCO₂ and warming was associated with accelerated MOC decomposition.

Conclusions

Long-term eCO₂ and warming might not alter the SOC stock but affect the bacterial community, accelerating C turnover among different SOC pools. The decrease in the MOC fraction of Fluvisol raises concerns about the SOC sustainability of this soil under climate change.

76. 题目: Extractable organic matter from PM2.5 inhibits cardiomyocyte differentiation via AHR-mediated m6A RNA methylation
文章编号: N25010614
期刊: Journal of Hazardous Materials
作者: Xiaoxiao Li, Shoushuang Zhao, Mengya Zhai, Yuqin Ma, Bin Jiang, Yan Jiang, Tao Chen
更新时间: 2025-01-06
摘要: An ever-increasing body of research has established a link between maternal PM2.5 exposure and congenital heart diseases in the offspring, but the underlying mechanisms remain elusive. We recently reported that activation of the aryl hydrocarbon receptor (AHR) by PM2.5 causes aberrant m⁶A RNA methylation, leading to cardiac malformations in zebrafish embryos. We hypothesized that PM2.5 can disrupt heart development by inducing m⁶A methylation changes through AHR in mammals. In this study, we observed that extractable organic matters (EOM) from PM_2.5 significantly impaired cardiomyocyte differentiation in embryonic rat cardiomyoblasts H9c2. Importantly, EOM exposure reduced global m⁶A methylation levels, which was reversed by AHR inhibition. Moreover, AHR, activated by EOM directly promoted the transcription of the demethylase, FTO, leading to global m⁶A hypomethylation. Specifically, AHR-induced FTO overexpression decreased the m⁶A methylation levels of Nox4 mRNA, resulting in NOX4 overexpression and subsequent oxidative stress in EOM samples. We then demonstrated that oxidative stress contributes to the inhibition of cardiomyocyte differentiation by EOM through suppression of Wnt/β-catenin signaling. In summary, our findings indicate that AHR activation by PM_2.5 directly enhances the expression of the demethylase, FTO, which increases NOX4 expression by reducing its m⁶A methylation. The oxidative stress caused by NOX4 overexpression inhibits Wnt/β-catenin signaling, thereby compromising cardiomyocyte differentiation.

77. 题目: Advancing micro-nano supramolecular assembly mechanisms of natural organic matter by machine learning for unveiling environmental geochemical processes.
文章编号: N25010613
期刊: Environmental Science: Processes & Impacts
作者: Ming Zhang, Yihui Deng, Qianwei Zhou, Jing Gao, Daoyong Zhang, Xiangliang Pan
更新时间: 2025-01-06
摘要: The nano-self-assembly of natural organic matter (NOM) profoundly influences the occurrence and fate of NOM and pollutants in large-scale complex environments. Machine learning (ML) offers a promising and robust tool for interpreting and predicting the processes, structures and environmental effects of NOM self-assembly. This review seeks to provide a tutorial-like compilation of data source determination, algorithm selection, model construction, interpretability analyses, applications and challenges for big-data-based ML aiming at elucidating NOM self-assembly mechanisms in environments. The results from advanced nano-submicron-scale spatial chemical analytical technologies are suggested as input data which provide the combined information of molecular interactions and structural visualization. The existing ML algorithms need to handle multi-scale and multi-modal data, necessitating the development of new algorithmic frameworks. Interpretable supervised models are crucial owing to their strong capacity of quantifying the structure-property-effect relationships and bridging the gap between simply data-driven ML and complicated NOM assembly practice. Then, the necessity and challenges are discussed and emphasized on adopting ML to understand the geochemical behaviors and bioavailability of pollutants as well as the elemental cycling processes in environments resulting from the NOM self-assembly patterns. Finally, a research framework integrating ML, experiments and theoretical simulation is proposed for comprehensively and efficiently understanding the NOM self-assembly-involved environmental issues.

78. 题目: Divergent responses of soil aggregate-associated organic carbon fractions and carbon flow pathways to land-use changes in karst ecosystems: Insights from δ13C signature
文章编号: N25010612
期刊: Catena
作者: Xiai Zhu, Youxin Shen, Xia Yuan, Ashutosh Kumar Singh, Liya Jin, Bin Yang, Chuang Yuan, Xiaojin Jiang, Wenjie Liu
更新时间: 2025-01-06
摘要: Land-use changes accompanying revegetation improve the sequestration of soil organic carbon (SOC) by accelerating aggregate formation. However, the intrinsic mechanisms of long-term C flow and sequestration following land-use changes in karst ecosystems remain largely unclear. We examined variations in aggregate-associated OC fraction and C flow pathways across four karst land uses (cropland, grassland, shrubland, and forestland). Result showed that agricultural cultivation disrupted soil aggregates and contributed to SOC depletion. Aggregate stability, labile and recalcitrant OC stocks generally increased along the vegetation restoration. The OC contents of bulk soils exhibited a strong positive correlation with the OC contents and mass proportions of macro- and micro-aggregates. Proportions of labile organic carbon (LOC) to SOC in the topsoil reduced with decreasing aggregate sizes, with being reshaped C pool by increasing LOC fraction in cropland. The δ13C values of bulk soil decreased with the sequence of vegetation restoration, indicating a decreasing turnover rate and C loss as land cover shifts from grass to forest. The δ13C was enriched as aggregate size decreased, with maximum value (−14.59 ‰) in the silt + clay fraction under grassland at the soil depth of 10–20 cm. Soil aggregate-associated C flow pathways predominantly occurred from macroaggregates to microaggregates and silt + clay size classes. This indicates that litter C input was incorporated into macroaggregates that were formed initially, while old SOC was often deposited in silt + clay fractions. Cropland demonstrated a greater intensity of C flows in topsoil compared to other land-use types, reflecting the fast turnover rate and loss of C under cropland soils. These results highlight that long-term soil labile and recalcitrant OC pools and C stabilization mechanisms at aggregate level are largely affected by land use. Appropriate land-use associated with grass and forest restoration maybe a promising way for enhancing SOC sequestration in karst areas.

79. 题目: Elevated methylmercury production in seasonally inundated sediments: Insights from DOM molecular composition
文章编号: N25010611
期刊: Journal of Hazardous Materials
作者: Xian Zhou, Tianrong He, Yongguang Yin, Tao Jiang, Pan Wu, Jiang Liu, Yongmin Wang, Deliang Yin, Enxin Liu, Siyi Ma, Qing Xie
更新时间: 2025-01-06
摘要: Seasonally inundated areas (SIA) within aquatic systems are characterized by elevated methylmercury (MeHg) production. Nevertheless, the response characteristics of dissolved organic matter (DOM) quality in SIA sediments, including its molecular compositions and structure, and their impacts on the MeHg production are not yet fully understood. This research gap has been addressed through field investigations and microcosm experiments conducted in a metal-polluted plateau wetland. The results revealed that DOM_SIA had lower levels of chromophoric DOM concentrations, protein-like fractions, molecular complexity, and debris size while exhibiting higher humic-like fractions, molecular weight, COO- groups, and bioavailability than DOM in permanently inundated areas (PIA). Compared with DOM_PIA, DOM_SIA was more easily biodegraded, and exhibited a higher adsorption capacity while lower binding affinity for Hg(Ⅱ). Moreover, MeHg synthesis by Desulfomicrobium escambiense was 29.6-fold higher in DOM_SIA than that in DOM_PIA, and DOM_SIA amendment also resulted in a higher MeHg production in the sediment. The PLS-PM model demonstrated that DOM compositions positively showed high contributions to MeHg levels in sediment porewater (0.51), while binding affinity had a negative pattern (-0.83), but adsorption capacity had a lower contribution (0.09). These findings provide an updated explanation for the elevated MeHg level in the SIA of aquatic systems, which are closely related to the adaptive response of DOM molecular composition and structure in the sediment.

80. 题目: Synchrony dynamics of dissolved organic carbon in high‐mountain streams: Insights into scale‐dependent processes
文章编号: N25010610
期刊: Limnology and Oceanography
作者: Lluís Gómez‐Gener, Nicola Deluigi, Tom J Battin
更新时间: 2025-01-06
摘要: In high‐mountain landscapes, organic carbon (OC) is often limited and heterogeneously stored in poorly developed soils, snow, ground ice, and glaciers. Climate change influences the dynamics of OC mobilization to—and processing into—the recipient streams. Dynamics vary from seasonal (e.g., snow melt in spring) to daily (e.g., ice melt in summer) depending on the location of the streams within the catchment. Capturing the temporal richness of stream biogeochemical signals has become a reality with the advent of high‐resolution sensors. In this study, we applied wavelet analysis to high‐frequency discharge (Q) and dissolved organic carbon (DOC) measurements from nine streams in the Swiss Alps to investigate the persistence of synchrony in Q (SQ) and DOC (SDOC) among streams, and their response to drainage network position, climate, and land cover gradients across different time scales. Our findings revealed that SQ and SDOC decayed non‐linearly over the first ~ 5 km and stabilized from this point onwards, indicating that localized controls influenced synchrony within single basins, but drivers operating at regional scale acted as synchrony stabilizers. We also showed that short‐term (0–10 d) SQ and SDOC were strongly influenced by the distance between streams and network connectivity. In contrast, catchment‐related properties (i.e., altitude or land cover) were more important drivers of SQ and SDOC dynamics at longer time scales (> 50 d). However, the degree to which local catchment properties controlled synchrony patterns at the longest timescales depended both on response variables (i.e., Q vs. DOC) and land cover (i.e., vegetation vs. glacier). Elucidating the most prominent timescales of SDOC is relevant given the hydrological alterations projected for high‐mountain regions. We show that glaciers impose a unique seasonal regime on DOC concentration, potentially overriding the effects of other local hydrological or biogeochemical processes during downstream transport. Consequently, SDOC dynamics in high‐mountain streams may change as glaciers shrink, thereby altering downstream opportunities for biogeochemical transformations.