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61. 题目: Photo–biodegradation drives organic matter-mediated carbon–nitrogen–sulfur cycling in the reservoir's surface-layer: A multi-index analysis
文章编号: N25120419
期刊: Environmental Research
作者: Haoyang Wang, Xinyu Lao, Khan M G Mostofa, Si-Liang Li, Cong-Qiang Liu, Jie Yuan, Jie Zhang, Fu-Jun Yue
更新时间: 2025-12-04
摘要: The synergistic regulation of dissolved organic matter (DOM) dynamics and coupled carbon-nitrogen-sulfur (C-N-S) cycling in the surface waters of cascade reservoirs by photochemical and microbial processes remains poorly understood. This study systematically examined DOM dynamics under both sunlight and dark conditions during consecutive 30-day experiments using unfiltered and filtered water from two reservoirs (Dongfeng and Yaoqiaoyu). Analyses included three-dimensional fluorescence (excitation-emission matrix, EEM) coupled with parallel factor analysis (EEM-PARAFAC), isotope techniques (δ¹⁵N–NO₃^– and δ¹⁸O–NO₃^–), and SO₄²⁻ measurements. Results revealed that sunlight-induced DOC decoupling arises from DOM release via phytoplankton photorespiration and its simultaneous photodegradation, evidenced by an increasing DOC trend in unfiltered samples under high-temperature conditions. This DOC release was further supported by the detection of three newly generated tyrosine-like, phenylalanine-like, and protein-like substances characterized using the EEM-PARAFAC model. Microbial respiration-induced DOC changes in darkness reflected differential microbial utilization of unstable versus recalcitrant DOM fractions and exhibited reservoir specificity. During late sunlight exposure (days 15–30) under optimal temperature conditions (air temperature: 20.0–26.9 °C), sustained phytoplankton-mediated fresh DOM production, combined with simultaneous photodegradation, resulted in minimal DOC losses. This process decouple DOC dynamics, leading to a substantial increase in DOC accompanied by extensive mineralization of its organic sulfur components to SO₄²⁻. NO₃⁻ transformation fluctuations were modulated by the phytoplankton assimilation and nitrification coupling processes, as supported by δ¹⁵N–NO₃^– and δ¹⁸O–NO₃^–. Based on these findings, we developed an integrated C–N–S cycle conceptual model that elucidates how light-dark cycles jointly drive DOM turnover by regulating phytoplankton photosynthesis, respiration, photodegradation, and microbial metabolism. Finally, this study clarifies the composition and transformation mechanisms of DOM in reservoir surface waters, providing concrete, process-based insights into how reservoirs, acting as ‘reactors,’ respond to and influence C–N–S cycles under climate change.

62. 题目: Enhanced fluoxetine removal from water via Fe/Cu-doped biochar-activated percarbonate under sunlight and aeration
文章编号: N25120418
期刊: Journal of Environmental Chemical Engineering
作者: Yang Wu, Zhi-hao Li, Xi-xi Lu, Zi-xuan Lin, Chang-ping Yu
更新时间: 2025-12-04
摘要: Fluoxetine (FLX), a widely prescribed antidepressant, is frequently detected in aquatic environments, raising significant ecological and environmental concerns. This study presents a sustainable strategy for FLX removal based on a biochar-supported advanced oxidation process (AOP). A bimetallic Fe/Cu-doped biochar (Fe@Cu-BC), derived from lignocellulosic waste and exhibiting a high specific surface area (646.42 m² g⁻¹), was synthesized and applied as a green catalyst to activate sodium percarbonate (SPC). By coupling natural sunlight and aeration, the Fe@Cu-BC/SPC system promoted the generation of reactive oxygen species (•OH and O₂^•⁻), leading to rapid and near-complete degradation of FLX. The degradation kinetics were well described by a modified pseudo-first-order model, and transformation products (TPs) were identified to elucidate possible degradation pathways. Despite the high FLX removal efficiency, the limited reduction in total organic carbon (TOC) suggests the need for additional post-treatment for complete mineralization. Overall, this work highlights the potential of converting agricultural and packaging wastes into multifunctional heterogeneous catalysts for emerging contaminant remediation, offering a cost-effective and environmentally friendly solution for pharmaceutical-containing wastewater treatment.

63. 题目: Constructing ferrihydrite confined in 3D boron-doped network biochar: simultaneous adsorption and oxidation of As(III) and tetracycline
文章编号: N25120417
期刊: Journal of Cleaner Production
作者: Yujiang Huang, Tong Hu, Sichen Li, Wenjun Zhou
更新时间: 2025-12-04
摘要: The concurrent remediation of metal and antibiotic co-contamination in soil/water is an urgent yet challenging task, particularly for developing green technologies that enable spontaneous degradation amidst competitive adsorption. Here, a bifunctional Fh/B@BC composite with rich exogenous defects and Fe-OH dual sites on separate planes was fabricated via dispersing ferrihydrite (Fh) in 3D Boron-doped biochar (B@BC, specific surface area ≈569 m2/g) to effectively co-remove As(III) and tetracycline (TC). Under dark, ambient air conditions, Fh/B@BC spontaneously co-removed over 92 % of aqueous TC and As(III), with 62.3 % of TC mineralization and 49.5 % of As(III) oxidation to less toxic As(V). DFT calculations and experimental results revealed that As(III) was adsorbed via inner-sphere complexation and Fe-As co-precipitation, meanwhile TC was mainly degraded by formed 1O2 via defects-mediated O2 activation, transforming into significantly less toxic products. The exogenous BC2O and BCO2 defects, and heterojunction structure boosted electron transfer, initiating successive 2e− oxygen reduction to generate 1O2, meanwhile BC2O, BCO2, and suboxide BOx donated electrons, promoting Fe(II) generation and TC degradation. The segregated BC redox sites and As(III) anchor on Fh (Fe-OH) improved site utilization of Fh/B@BC, and the negatively charged carbon enhanced Fe-C interfacial catalysis and Fe-As co-precipitation. Furthermore, the multi-plane site distribution of Fh and B@BC separates the adsorptions/oxidation of TC and As(III) to avoid competitive adsorption and ferrolysis on Fh/B@BC. Overall, this study synchronously overcame the reactivity dilemma faced by biochar and Fe minerals, inspiring the material design for green co-contamination remediation in redox-dynamic conditions like fluctuating aquifers and paddy soils.

64. 题目: Soil organic matter decomposition in semi-arid mangrove stands (New Caledonia)
文章编号: N25120416
期刊: Catena
作者: Sarah Louise Robin, François Baudin, Claude Le Milbeau, Andrea C Alfaro, Cyril Marchand
更新时间: 2025-12-04
摘要: Organic matter (OM) dynamics in mangrove forests have been studied extensively in terms of the capacity of their soils to store organic carbon. While δ13C, δ15N, and C/N values for mangrove soils and sources are well reported, other indicators of OM maturity and composition are lacking. In this study, soil OM decomposition processes were investigated for a semi-arid bay head mangrove forest in New Caledonia. Mangrove tissues and 20-cm soil cores were collected in monospecific stands of Avicennia marina and Rhizophora stylosa. The isotopic compositions of the samples were assessed, along with their molecular compositions (lignin-derived phenols and neutral carbohydrates). Rock-Eval analysis was also performed on the samples to investigate OM characteristics. Results showed that stable isotope ratios and Rock-Eval parameters followed similar vertical trends beneath both species indicating the influence of depth on OM state. However, the more anoxic conditions beneath R. stylosa limited OM decomposition as shown by the lower TpS2 values (indicator of OM thermal stability). Neutral carbohydrates and, surprisingly, lignin-derived phenols, were lost at higher rates than bulk organic carbon beneath both mangrove species. Selective degradation of individual compounds was observed, and species-dependent variations associated with the redox conditions and the OM sources were identified. We suggest that lignin was degraded, even in anoxic environments, because of the amount of labile lignocellulosic components in the soil. These findings enhance our understanding of OM dynamics in mangrove ecosystems, shedding light on the mechanisms underlying carbon cycling and their implications for global carbon storage and ecosystem management.

65. 题目: Conservation tillage and wheat straw managements improve soil organic carbon sequestration via calcium-mediated microbial communities and aggregate stability in Calcaric Cambisols
文章编号: N25120415
期刊: Journal of Environmental Management
作者: Zixuan Han, Shengping Li, Aurore Degré, Huizhou Gao, Fengjun Zheng, Xiaojun Song, Angyuan Jia, Xueping Wu
更新时间: 2025-12-04
摘要: Conservation tillage improves soil organic carbon (SOC) management by balancing microbial decomposition and physico-chemical protection. Minerals stabilize SOC, but how tillage practices affect calcium (Ca) speciation and its role in microbial–mineral–organic matter interactions in calcareous soils remains unclear. Thus, a 22-year tillage experiment and soil incubation were conducted to investigate Ca-mediated SOC sequestration and mineralization. Conservation tillage, including no-tillage with straw mulch (NTS) and subsoil tillage with straw mulch (STS), increased SOC storage by 9.9–14.3 % at 0–20 cm soil depth by promoting organo-Ca associations, compared to conventional tillage without straw return (CTN) and reduced tillage without straw return (RTN). Moreover, NTS and STS increased aggregate stability and macroaggregate proportion, reducing total SOC mineralization, as macroaggregates had lower SOC mineralization than microaggregates. In aggregates, increased exchangeable Ca was linked to higher particle- and mineral-associated SOC and lower SOC mineralization, showing positive (p < 0.01) and negative (p < 0.001) relationships, respectively. Compared to CTN and RTN, long-term NTS and STS not only promoted the transformation of CaCO3 to exchangeable Ca, but also increased microbial biomass, especially the proportion of Gram-negative and arbuscular mycorrhizal fungi. Mechanistically, higher Ca2+ reshaped bacterial communities and promoted the microbial by-product binding to the minerals to form stable organo-Ca complexes, which was supported by the positive correlations between Ca2+, microbial composition and SOC content (PLS-PM, p < 0.01). Overall, conservation tillage increased Ca availability for carbon binding by mediating microbial structures, thereby promoting aggregate protection and SOC stability in Calcaric Cambisols.

66. 题目: Interplay and selectivity of selected pharmaceuticals and organic contaminants adsorption onto magnetic biochar: Mechanistic insights
文章编号: N25120414
期刊: Journal of Environmental Management
作者: Yurim Kim, Jaegwan Shin, Changgil Son, Deokhwan Kim, Hojung Rho, Kangmin Chon, Min Jang, Yeomin Yoon, Byung-Moon Jun
更新时间: 2025-12-04
摘要: Biochar (BC) is widely recognized as an effective adsorbent owing to its porous structure, while magnetic biochar (MBC) offers the added advantage of easy separation and enhanced performance. However, few studies have systematically investigated competitive adsorption among multiple contaminants under environmentally relevant conditions. The adsorption characteristics of nine selected organic contaminants onto raw biochar and magnetic biochar were compared under varying conditions (pH, ionic strength, and organic substances). MBC exhibited superior adsorption capacity because of its increased surface area from 6.5 (BC) to 1,101 m2 g−1. Ketoprofen (KP), antipyrine (AP), and propranolol hydrochloride (PH) were selected as representative anionic, neutral, and cationic contaminants, respectively, to investigate the competitive adsorption behavior of MBC. MBC showed higher adsorption for KP and PH compared to AP, mainly through electrostatic interactions, π–π stacking, and hydrogen bonding. The adsorption mechanisms for KP and PH predominantly followed monolayer chemisorption, which was best described by pseudo-second-order kinetic and Langmuir isotherm models, indicating spontaneous (ΔG = −4.4 to −12.1 kJ·mol-1) and exothermic (ΔH = −33.7 to −35.0 kJ·mol-1) processes. X-ray photoelectron spectroscopy analyses further supported electron donor–acceptor and electrostatic interactions, which occurred between the functional groups of MBC and the adsorbed contaminants, as evidenced by binding energy shifts in C1s, O1s, and Fe2p spectra. The competitive effects of background ions and organic substances emphasize the multifunctional adsorption capacity of MBC. Importantly, MBC maintained high reusability over multiple adsorption-desorption cycles, highlighting its practical application potential for contaminant removal.

67. 题目: Characteristics of organic phosphorus in sediments from lakes: Regeneration for eutrophication or a geological record in the Anthropocene?
文章编号: N25120413
期刊: Water Research
作者: Xiaojie Bing, Yuanrong Zhu, Huihui Ma, Juan Jiang, Yue Li, Qihao Zhou, Yidan Tan, Yuyao Wang, Qingshuai Song, Sailan He, Fengchang Wu
更新时间: 2025-12-04
摘要: Organic phosphorus (Po) plays a pivotal role in watershed biogeochemical cycling and lake eutrophication, but its potential as an indicator of Anthropocene stratigraphic change remains insufficiently understood. This study integrates carbon and nitrogen isotope analyses with 31P NMR spectroscopy of representative plants, soils, and sediment profiles to elucidate the compositional characteristics, depositional history, and anthropogenic linkages of Po in an alpine meadow lake (Yamdrok Lake, YH) and a temperate forest oligotrophic lake (Sihailongwan Lake, LW), and further compares these systems with Dianchi Lake (DC), a eutrophic lake in China. Sedimentary Po concentrations spanned 165.5-531.1 mg kg⁻¹ (LW) and 34.1-87.4 mg kg⁻¹ (YH), dominated by monoester phosphates (79.2 and 87.4% of total Po, respectively). Terrestrial C3 vegetation drove Po accumulation in LW, particularly inositol phosphates, while authigenic and aquatic plant sources prevailed in YH. Oligotrophic sediments exhibited prolonged degradation half-lives of Po compounds (DNA phosphate: 88-170 yr; inositol phosphates: 130-179 yr), 4-5-fold longer than in hypereutrophic systems (e.g., DC), where algal-mediated internal phosphorus cycling sustains recurrent blooms. Critically, stratigraphic C/labile mono-P ratios emerged as a novel proxy, capturing century-scale anthropogenic perturbations (e.g., deforestation, urbanization) and aligning with Anthropocene demarcation criteria. These findings redefine sedimentary Po dynamics, highlighting its dual role as both a driver of eutrophication feedback and an archive of human-environment interactions in freshwater systems.

68. 题目: Mechanisms underlying enhanced simultaneous removal of tetracycline and nitrate by Paracoccus denitrificans immobilized on biochar
文章编号: N25120412
期刊: Bioresource Technology
作者: Wenjie Xu, Meng Jiang, Weizi Zhang, Xi Hong, Jin Xu, Jiangpeng Xue, Ming Tang
更新时间: 2025-12-04
摘要: Tetracycline (TC) and nitrate (NO3−-N) co-contamination poses significant threats to aquatic ecosystems. In this study, an effective strain, identified as Paracoccus denitrificans XW1, was isolated and immobilized on wheat straw biochar for simultaneous TC and NO3−-N removal. Results demonstrated a significant enhancement in TC and NO3−-N removal by biochar-immobilized XW1 (IB), with IB exhibiting 1.29 to 8.90-fold greater TC removal and 1.03 to 2.57-fold higher NO3−-N removal than free XW1 cells (FB) across varied environmental conditions. Mechanistic studies revealed that the enhanced TC removal was predominantly adsorption-dependent, whereas NO3−-N elimination was primarily driven by biochar-facilitated biodegradation. Over five reuse cycles, IB sustained enhanced NO3−-N removal (38.56% to 94.76%) but exhibited gradual TC decline (67.22% to 12.80%) from adsorption saturation, while FB rapidly lost TC degradation capacity within two cycles. Biochar promoted antioxidant enzyme production to mitigate oxidative stress induced by TC. Meanwhile, biochar stimulated extracellular polymeric substances (EPS) secretion, particularly humic acid-like substances, which concurrently enhanced TC adsorption and facilitated denitrification. Transcriptomics analyses further revealed that biochar upregulated genes associated with the tricarboxylic acid (TCA) cycle, ATP-binding cassette (ABC) transporters, and quorum sensing in XW1, consequently enhancing energy metabolism, enzymatic detoxification, and bacterial cooperation. This synergy enabled the efficient simultaneous bioremediation of TC and NO3−-N. This work provides a sustainable biochar-microbe agent for complex water remediation.

69. 题目: Distinct roles of Fe-based amendments in Cu/Zn passivation during composting: Microbial community shifts, resistance gene suppression and humic acid formation
文章编号: N25120411
期刊: Journal of Environmental Management
作者: Yingchao Zhang, Tianhuan Chen, Jun Ma, Qi Chang, Ruxue Wang, Xuli Gong, Hongmei Sun, Hongqiong Zhang, Laizhou Song
更新时间: 2025-12-04
摘要: This study explored the effects and mechanisms of three Fe-based amendments (Fe(0), Fe2O3, and Fe3O4) on Cu and Zn passivation during composting of chicken manure (CM) and wine grape pomace (WGP). All amendments enhanced humic acid (HA) formation, with Fe2O3 showing the strongest effect. Cu passivation efficiency followed Fe(0) (91 %) > Fe2O3 (74 %) > Fe3O4 (69 %), while Zn passivation ranked Fe2O3 (39 %) > Fe(0) (30 %) > Fe3O4 (30 %). Fe(0) promoted Cu immobilization by enriching core bacteria (e.g., Gallicola, Corynebacterium) and suppressing Cu-resistance genes (cus, pco), whereas Fe2O3 facilitated Zn stabilization mainly through HA–Zn2+ complexation and reduction of the czc gene. Although Fe3O4 exhibits lower passivation efficacy on Cu and Zn compared to Fe2O3, it still enhances the conversion of certain functional groups and promotes mineral formation. Additionally, mineral production also contributed to Cu passivation. Fe(0) increased by 55 % through releasing Fe2+ and participating in the sulfidation reaction between Cu and S, leading to the formation of Cu2Fe2S3. Random forest analysis further indicated that Gallicola (7 %–10 %) was the key contributor to Cu passivation, while HA (7 %–10 %) played the dominant role in Zn passivation. These findings highlight the distinct roles of Fe-based amendments in metal immobilization, offering viable strategies for improving the environmental safety and resource efficiency of composting.

70. 题目: Impact of extracellular polymeric substances from Skeletonema costatum on the combined toxicity of microplastics and antibiotics in estuarine environment
文章编号: N25120410
期刊: Marine Pollution Bulletin
作者: Jie Lai, Jianhuang Su, Zongling Li, Yan Zheng, Dinglin Hou, Zifeng Zhou, Jiabao Zhu, Bin Lin, Peiyong Guo
更新时间: 2025-12-04
摘要: Estuarine ecosystems act as major sinks for land-derived pollutants entering the marine environment, and the co-occurrence of microplastics and antibiotics, along with their potential ecological effects on estuarine microalgae, has become an increasingly prominent marine environmental issue. However, little is known about the role of extracellular polymeric substances (EPS) from estuarine microalgae on the joint toxicity of microplastics and antibiotics. This study investigated the protective role of EPS in the typical estuarine diatom Skeletonema costatum by comparing physiological responses with and without EPS under combined stress from polypropylene (PP) and polyethylene (PE) microplastics and the antibiotic sulfamethazine (SM2). To further elucidate the regulatory mechanisms through which microalgal EPS responds to co-stress, changes in EPS composition under combined stress were investigated. The results showed that microalgal with EPS exhibited varying degrees of oxidative stress under combined exposure, whereas high-concentration treatments may inhibit SOD production due to cell death. EPS removal compromised the algal resistance, leading to severe chlorophyll a damage, a significant reduction in the DNA synthesis preliminary phase (G0/G1), and a notable increase in the apoptotic cells (Sub-G1). The protein and polysaccharide contents in tightly bound EPS were considerably reduced by combined stress. This study reveals that EPS plays a crucial protective role in microalgae under combined pollution stress by regulating its composition and physicochemical properties. These findings provide a theoretical basis for accurately assessing the ecological risks of emerging contaminants in estuarine environments and offer important guidance for developing pollution control strategies based on biological processes in estuarine environments.

71. 题目: Restoration age enhances soil organic carbon sequestration primarily through plant-derived carbon in a coastal wetland
文章编号: N25120409
期刊: Plant and Soil
作者: Qixue Cao, Xiaojie Wang, Mingliang Zhao, Qianqian Zhao, Xiaojing Chu, Lianjing Wang, Weimin Song, Xiaoshuai Zhang, Guanxuan Han
更新时间: 2025-12-04
摘要: Aims Plant- and microbial-derived carbon (C) are the primary sources of soil organic carbon (SOC) in coastal wetlands, yet their contributions across vegetation restoration chronosequences remain poorly understood. Methods Using biomarker approaches, we investigated the dynamics of total lignin phenols (VSC) and microbial necromass C (MNC) in SOC over a 20-year restoration chronosequence (0, 4, 8, 11, and 20 years) in the Yellow River Delta of China. Results Restoration age significantly increased VSC contributions to SOC (1.9%–7.1%) but had limited effects on MNC, which averaged 28.64%—lower than anticipated. The contents of VSC, MNC, vanillyl phenols, syringyl phenols, cinnamyl phenols, fungal necromass C (FNC) and microbial biomass C (MBC) were positively correlated with SOC content. However, Bacterial necromass C (BNC) showed no significant correlation with SOC. Plant coverage and soil C/N ratio were the main drivers of C source changes, showing significant positive and negative linear relationships with VSC and MNC content, respectively. Structural equation modeling revealed that plant-derived C was the strongest positive predictor of SOC. In contrast, microbial-derived C exhibited a weak but statistically significant negative path coefficient, possibly due to reduced necromass accumulation efficiency or rapid microbial turnover under certain restoration conditions. Conclusions Although both VSC and MNC had a positive response to restoration age, increasing plant-derived C affected by plant cover and biomass is the main driver of enhanced SOC sequestration in coastal wetlands, compared to microbial-derived C.

72. 题目: Long‐Term Reclamation of Sandy Land Enhances Deep Soil Carbon Storage and Stability via Mineral‐Associated Organic Carbon Accumulation
文章编号: N25120408
期刊: Land Degradation & Development
作者: Qingqi Wang, Jing Tian, Xu Feng, Wai Yu, Xiaoting Han, Gehong Wei, Honglei Wang
更新时间: 2025-12-04
摘要: The long‐term impacts of intensive agricultural reclamation on the turnover and stabilization of soil organic carbon (SOC) in desert ecosystems remain poorly understood, particularly throughout deep soil profiles. Using a paired‐site approach in northwest China, we investigated how the conversion of sandy land to cropland following 15 years of reclamation shaped the vertical distribution (0–200 cm) and composition of SOC fractions, focusing on particulate (POC) and mineral‐associated organic carbon (MAOC). Our results show that over 60% of total SOC stock is stored below 60 cm depth, with deep‐soil carbon increasing significantly from 18.4 t ha −1 in natural land to 27.2 t ha −1 following reclamation, underscoring the critical role of subsoil carbon sequestration in arid regions under land‐use change. Reclamation fundamentally shifted SOC composition from POC dominance to MAOC dominance, with subsoil MAOC increasing by up to 133.9%, indicating enhanced stability. A strong correlation between microbial necromass carbon (MNC) and MAOC in the topsoil suggests a predominantly microbial‐mediated pathway for MAOC formation in surface layers. MAOC correlated negatively with aliphatic‐C and positively with polysaccharide‐C, collectively pointing to microbial transformation and subsequent mineral stabilization as key processes in MAOC formation. Key factors including total nitrogen, available nitrogen, clay content, and soil moisture were identified as primary predictors of MAOC accumulation, with depth‐dependent influences. These findings demonstrate that long‐term reclamation markedly promotes MAOC accumulation and carbon sequestration capacity in deep soil, while clarifying associated biological and physicochemical stabilization mechanisms. These insights into SOC persistence under land‐use change are crucial for developing sustainable soil management and climate‐adaptive agriculture in drylands.

73. 题目: Millennial- to centennial-scale record of organic carbon accumulation and its periodic occurrence in the Yellow Sea since the last deglaciation
文章编号: N25120407
期刊: Palaeogeography, Palaeoclimatology, Palaeoecology
作者: Yuying Zhang, Limin Hu, Yazhi Bai, Lina Jin, Hyung Jeek Kim, Na Li, Song Zhao, Jun Ye, Yonghua Wu, Xiao Wu, Xiting Liu, Xun Gong, Houjie Wang
更新时间: 2025-12-04
摘要: Organic carbon (OC) burial in marginal seas play a crucial role in the global carbon cycle. The South Yellow Sea (SYS), a typical semi-enclosed shelf sea, exhibits intense land-sea interactions and high sensitivity to sea-level fluctuations and climate changes, which shape a distinctive OC burial regime. However, systematic investigations of OC burial in the SYS across different timescales since the last deglaciation remain limited. We present a comprehensive analysis of core H12 (~16.6 ka BP) from the SYS, integrating grain size, OC contents, stable carbon isotopes (δ13Coc), n-alkane biomarkers and OC burial fluxes. Our results reveal a substantial input and effective preservation of terrestrial higher plants during the low sea-level period, coinciding with a higher terrestrial OC accumulation rate (OCterr-MAR) and prevalent herbaceous plants-derived organic matter. Following sea-level rise, the OCterr contribution fell sharply (from 68 % to 34 %), although a distinct OCterr-MAR peaked at ~8 ka BP probably driven by an abrupt cooling event. Under high sea-level and relative stable hydrodynamic conditions, high-resolution OC variability exhibited 1000-yr and 350-yr cycles. The millennial-scale variation of OC burial is likely associated with solar forcing, while the centennial-scale periodicity in the late Holocene is probably ascribed to the intensity of the regional current vortex system, regulated by monsoon and ocean circulation dynamics. These findings further clarify the OC burial regime in marginal seas controlled by rapid sea-level rise and sedimentary hydrodynamic forcing, and highlight the sensitivity of millennial-to centennial-scale OC dynamics to climatic variability.

74. 题目: Evaluating the effectiveness of thiourea-modified biochar derived from wheat straw for Cd, Ni, and Zn adsorption in soil.
文章编号: N25120406
期刊: Environmental Science and Pollution Research
作者: Leila Gholami, Ghasem Rahimi
更新时间: 2025-12-04
摘要: In recent years, researchers have focused on developing innovative biochar modification techniques to enhance adsorption efficiency and reduce the mobility and bioavailability of heavy metals. However, few studies have investigated the application of modified biochar in heavy metals-contaminated soils, with most research focusing on aqueous solutions. In Iran, the potential of biochar as an effective adsorbent for removing heavy metals from contaminated soils, especially acidic soils, has been largely overlooked. The effectiveness of biochar is influenced by both the type of biomass used and the method of modification. Additionally, there is a significant gap in current literature regarding the research on thiourea as a potential modification agent for biochar. This study focused on the characteristics of thiourea-modified wheat straw biochar (TWB) and its effects on the adsorption isotherms and kinetics of heavy metals (Cd, Ni, and Zn) in acidic soil. The biochar was produced from wheat straw in an oxygen-free furnace at a temperature of 550 °C for 3 h, with a heating rate of 25 °C per min. To enhance the adsorption efficiency, thiourea was used to modify the wheat straw biochar (WB). The findings revealed that the thiourea modification reduced the carbon content but increased the nitrogen, hydrogen, sulfur, oxygen levels, specific surface area, cation exchange capacity (CEC), and pH compared to unmodified biochar. Adsorption isotherms and kinetics analyses indicated that the Langmuir model best described the adsorption of heavy metals in soil treated with both TWB and WB, while the pseudo-second-order model more accurately represented the adsorption kinetics. The results indicated that the adsorption of Cd, Ni, and Zn in soil treated with 8% TWB was significantly higher than in the control, achieving levels of 6164.45, 4684.47, and 4233.58 mg kg-1, respectively. This study demonstrated that TWB enhances the adsorption of heavy metals due to its advantageous properties, which include an optimal pH, high CEC, a variety of functional groups, a large specific surface area, and a porous structure. Therefore, thiourea-modified wheat straw biochar serves as an effective, economical, and environmentally friendly adsorbent for immobilizing heavy metals and reducing their bioavailability in acidic contaminated soils.

75. 题目: Binding affinities of arsenic to environmental dissolved organic matter: Behavior differences of hydrophilic/phobic fractions and environmental implications
文章编号: N25120405
期刊: Science of the Total Environment
作者: Ning-Xin Wang, Yi-Han Cheng, Yu-Lai Wang, Li-Juan Zhang, Jin Xu
更新时间: 2025-12-04
摘要: The As binding properties of environmental water-soluble organic matter (WSOM) fractions from the Chaohu Lake Basin were investigated following their separation and extraction based on polarity. Specifically, the hydrophilic component (HPI-WSOM) constituted 8.7 % to 59.2 %, the transitional component (TPI-WSOM) made up 19.1 % to 74.1 %, and the hydrophobic component (HPO-WSOM) represented 17.2 % to 37.5 % of the bulk WSOM dissolved organic carbon (DOC) content. The experimental approach involved measuring As concentrations both inside and outside a dialysis bag during complexation equilibrium. The equilibrium times and strengths were analyzed, and the findings revealed that WSOM derived from aquatic plants, which had the highest percentage of HPO, required the longest time to reach equilibrium, suggesting a more extended period was necessary to achieve balance. The adsorption efficiency (AE) of As was assessed by examining the influence of the DOC to As concentration ratio (Fc) on As complexation. A strong linear correlation was observed between AE and Fc (with R2 values ranging from 0.85 to 0.99), indicating a reliable prediction of As speciation and, consequently, its bioavailability in natural waters. The binding capacity of As to different environmental WSOM, as well as the hydro-philic/phobic fractions, was quantified using the conditional distribution coefficient (Kd). Sedimentary WSOM exhibited the highest Kd values, while that from farmland soil showed the lowest, with this trend positively correlating with the combined percentage of HPI and TPI DOC concentration percent in the samples. The results also highlighted the key role of TPI fractions in the complexation process.

76. 题目: Eliminating the influence of free iron oxides on the prediction of organic matter in red soils using Vis-NIR reflectance spectroscopy
文章编号: N25120404
期刊: Geoderma
作者: Nuo-Xi Qiu, Xian-Li Xie, Lang Guan, An-Bo Li, Jie Liu, Ming Liu, Yu-Guo Zhao
更新时间: 2025-12-04
摘要: Free iron oxides (Fed) in red soils negatively affect the accuracy of organic matter (OM) prediction using visible and near-infrared (390–1000 nm) spectroscopy. Based on a typical red soil sample set (n = 36, including both Fed- and OM-removed samples), this study investigated the spectral characteristics of Fed and OM, and applied the maximum overlapping discrete wavelet transform (MODWT) to extract wavelengths associated with Fed spectral features across different wavelet components. We evaluated whether removing the extracted Fed spectral features from the red soil spectra could improve the accuracy of OM prediction by using three datasets: (A) regional-scale, laboratory-measured dry soil spectral dataset; (B) field-scale, laboratory-measured moist soil spectral dataset; and (C) field-scale, unmanned aerial vehicle-measured soil spectral imaging dataset. Three calibration algorithms—partial least squares regression (PLSR), linear support vector machine (LSVM), and random forest (RF)—were employed for OM prediction. Compared with raw spectra as a baseline, preprocessing via Fed spectral feature removal improved the prediction accuracy of OM in red soils for all datasets and algorithms tested. The average percentage improvement across all datasets is 19.63 % in RMSEval-ori and 93.80 % (absolute values increased by 0.21 averagely) in R2val-ori. The results confirm that wavelet-decomposed Fed spectral feature removal preprocessing improves the accuracy of OM spectral prediction in red soils, and demonstrate the transferability of the feature extraction parameters across different application scenarios.

77. 题目: Chemical characterization of dissolved organic matter in a hurricane-impacted estuary: linking chromophores, lignin phenols, amino acids and mass spectrometry-based compositions
文章编号: N25120403
期刊: Estuarine, Coastal and Shelf Science
作者: Mohammad Al Mukaimi, Huda Alaskar, Ge Yan, Karl Kaiser
更新时间: 2025-12-04
摘要: Hurricane Harvey brought unprecedented precipitation over an urbanized watershed, causing extensive flooding and delivering a significant pulse of terrigenous material to Galveston Bay. This study employs a comprehensive suite of techniques, including optical spectroscopy, chemical analyses of lignin phenolds and enantiomeric amino acids, and mass spectrometry, to characterize the sources, compositions and transformations of dissolved organic matter (DOM) in response to this extreme weather event. The results revealed distinct temporal shifts in DOM composition, initially dominated by terrigenous, aromatic-rich constituents shortly after the storm. These compositions transitioned to a more diverse mixture of degraded terrestrial material and phytoplankton-derived autochthonous DOM, driven by extensive microbial processing and the secondary input of bacterial organic matter. This dynamic evolution demonstrates the rapid response of estuarine systems to extreme disturbances, with indications that the bay's ecosystem can recover from episodic events, although the impacts of repeated or sequential disturbances remain uncertain. The integration of optical, chemical, and mass spectral analyses provided complementary insights into DOM dynamics, highlighting the value of using multiple characterization tools. While chromophoric DOM (CDOM) features and concentrations of biochemicals offered robust indicators of DOM composition, mass spectrometry data further elucidated specific transformation pathways. This comprehensive approach revealed key links between microbial community activity and DOM composition, reflecting preferences for certain DOM components and the influence of nutrient and light conditions. These findings emphasize the profound impacts of extreme weather events on estuarine carbon cycling and biogeochemical dynamics, offering critical insights into the resilience of coastal systems amid increasing climate variability.

78. 题目: Methane Biogeochemical Turnover Constrains Arsenic transformation in Groundwater Systems: Organic Molecular Signatures and Microbial Functional Networks
文章编号: N25120402
期刊: Water Research
作者: Xianjun Xie, Enyu Li, Honglin Jiang, Kunfu Pi, Lu Yan, Shuai Shen
更新时间: 2025-12-04
摘要: Arsenic (As) contamination of groundwater is primarily driven by microbially mediated redox processes and the dynamic evolution of dissolved organic matter (DOM). The influence of cycled methanogenesis and methane oxidation processes on As species transformation in geogenic As-contaminated groundwater, however, remain mechanistically elusive. In this study, quantitative relationships among DOM molecular characteristics, microbial functional networks, and As speciation were established using sediment microcosm experiments, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), and metagenomic sequencing. The results indicate that rates of methanogenesis and methane oxidation are regulated by thermodynamic properties of DOM. Labile DOM promoted As(III) mobilization at a rate of 1.04 μg kg⁻¹ d⁻¹ through methyl-related metabolism. Remarkably, enhanced methane oxidation further elevated the As(III) generation rate to 3.30 μg kg⁻¹ d⁻¹, underscoring the accelerating effect of methane cycling on As release. In contrast, humified DOM decoupled the geochemical linkage between iron and As. Microbial succession governed the redox transitions, as the proliferation of methanogens substantially increased methane production (up to 7.23 mg kg⁻¹ d⁻¹), while methanotrophs enhanced oxidation rates from 94.99 to 190.76 mg kg⁻¹ d⁻¹. This microbial progression coupled sulfate and As(V) reduction through the up-regulation of key functional genes (dsrAB, arsC). Energy conversion during DOM biodegradation governs As migration stages. These findings highlight the interactive constraints on As speciation dynamics by molecular characteristics of DOM and microbial functional networks during methane biotransformation processes in groundwater systems. This research provides new mechanistic insights into As biogeochemical cycling in geogenic contaminated groundwater.

79. 题目: Can agroforestry–conservation agriculture integration improve soil organic matter (SOM) quality? An FTIR–spectroscopic investigation
文章编号: N25120401
期刊: Soil and Tillage Research
作者: null Bharti, Sovan Debnath, Asha Ram, Avijit Ghosh, Susheel Kumar Singh, Bijoy Chanda, Naresh Kumar, Inder Dev, Tufleuddin Biswas, Sushil Kumar, Amit Kumar Singh, Badre Alam, Rajendra Prasad, Ayyanadar Arunachalam
更新时间: 2025-12-04
摘要: Agroforestry and conservation agriculture both mimic natural ecosystems and can jointly enhance sustainability and soil resilience by augmenting carbon sequestration and soil organic matter (SOM). Despite this complementarity, efforts to integrate these practices into a synergistic system that can improve SOM composition and humification indices remain limited. Here, we assessed the effects of agroforestry systems and croplands (in upland and lowland ecologies) on SOM quality in the degraded semi-arid land in Central India at 0–20 and 20–40 cm soil depths. Systems included a long-term teak (Tectona grandis)-based agroforestry (AF (T)) and agroforestry integrating conservation agriculture with sorghum–chickpea (CAF (S–C)) or maize–linseed (CAF (M–L)) rotations. SOM quality was characterized by Fourier-transform infrared (FTIR) spectroscopy that focused on the humification indices of fulvic acid (FA) and humic acid (HA). Results revealed dissimilarities in the abundance of carbon (C)- and oxygen (O)-functional groups between humic and fulvic acids . For example, conservation agroforestry systems exhibited broader spectral signatures and a greater presence of –COOH groups, hydrogen bonding (–OH), –OH deformation, and C–O stretching vibrations of polysaccharides (1037–1162 cm−1) and phenolics (3700–3620 cm−1) as well as an increase in lignin-origin phenolic compounds (1370 cm−1), indicating more advanced SOM decomposition and humification than conventional agroforestry and croplands. Humification indices followed the trend: conservation agroforestry > agroforestry > cropland. Variations between CAF (S–C) and CAF (M–L) further suggest that crop choice modulates these effects. Our findings demonstrate that transitioning cropland to agroforestry enhances soil humification, and that combining agroforestry with conservation agriculture can accelerate these improvements even over short timescales.

80. 题目: Fluorescence as an Indicator of Dissolved Organic Matter Sources in 31 Subtropical Urban Lakes at the Lower Yangtze River
文章编号: N25120314
期刊: ACS ES&T Water
作者: Ping Jiang, Yang Wang, Y Jun Xu, Huaiwei Sun, Liuqing Zhang, Xing Li, Chen Ye, Bingjie Ma, Siyue Li
更新时间: 2025-12-03
摘要: To explore the relationship between the fluorescence properties of dissolved organic matter (DOM) and trophic states in aquatic systems, this study analyzed 488 water samples from 31 subtropical shallow lakes in central China over a cool-dry and a warm-wet season using excitation–emission matrix parallel factor analysis (EEM-PARAFAC) and machine learning. The lakes had variable trophic states ranging from oligotrophic to hypereutrophic. The results show that autochthonous DOM dominated in these lakes and that its contribution was significantly lower in the warm-wet season than in the cool-dry season. Tryptophan-like C1 was more abundant in the cool-dry season (21.72%) than in the warm-wet season (19.96%), while tyrosine-like C2 and terrestrial humic-like C4 were more abundant in the warm-wet season (29.30% and 18.10%) than in the cool-dry season (27.69% and 16.67%). Trophic states were strongly associated with the presence of microbial humic-like and tryptophan-like DOM components, as well as the Freshness index (β:α). Based on these findings, we conclude that the DOM fluorescence characteristics are reflective of trophic states in these subtropical shallow lakes. More studies on the linkage of DOM characteristics─trophic states are needed in other ecoregions and deep lakes.