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41. 题目: Molecular interference for surface sites as a hidden driver of coagulation impairment in wastewater-impacted drinking water production
文章编号: N26073004
期刊: Water Research
作者: Mengjie Liu, Baofeng Zhu, Nigel J D Graham, Wenzheng Yu
更新时间: 2026-07-30
摘要: The presence of effluent organic matter (EfOM) in drinking water sources, a consequence of unplanned potable reuse, challenges the efficacy of conventional coagulation processes. This study employs a multi-scale analytical approach to reveal that EfOM does not simply increase organic loading but triggers a molecular-level interference with natural organic matter (NOM) for active sites on floc surfaces, manifested as preferential adsorption of EfOM components. Through integrated application of FT-ICR-MS, X-ray photoelectron spectroscopy, floc characterization, and contact angle measurements, we demonstrate that EfOM components, particularly lipid- and protein-like molecules, exhibit preferential adsorption onto reactive surface hydroxyl groups on aluminum flocs, thereby inhibiting the removal of aromatic, high-molecular-weight NOM fractions. This competitive adsorption enriches floc surfaces with hydrophilic C–O and COOH groups, elevating electrostatic repulsion and impairing inter-floc bridging, ultimately yielding smaller, less-settleable flocs. As a result, finished water contains a more diverse organic portfolio. It shows significant enrichment in heteroatomic (N, S, P) species characterized by high unsaturation and a low oxidation state, which are molecular features that have been previously linked in the literature to enhanced disinfection byproduct formation potential. Our study elucidates the mechanistic pathways linking molecular interference to impaired treatment performance, and underscores the need to develop advanced treatment strategies to mitigate downstream water quality risks.

42. 题目: Discriminating Winter-Drought and Summer-Flood Regimes Using CDOM Optical Proxies: A Proof-of-Concept Analysis in Poyang Lake, China
文章编号: N26073003
期刊: Water Research
作者: Qi Huang, Lizhen Liu, Lamees Shah, Yongming Wu, Tianxiang Wang, George Arhonditsis
更新时间: 2026-07-30
摘要: Freshwater lake ecosystems are increasingly exposed to hydro-climatic extremes, with profound implications for water quality and carbon cycling. However, rapid diagnostic tools capable of resolving the collective impacts of these extremes remain limited. Here, we test the hypothesis that the optical properties of chromophoric dissolved organic matter (CDOM) provide a sensitive and integrative proxy for distinguishing the two hydro-climatic states. Using Poyang Lake (China) as a model system, we characterized CDOM dynamics under two contrasting coupled hydro-climatic states -winter extreme drought (January 2015) and summer extreme flood (July 2016) -through combined absorbance and fluorescence spectroscopy coupled with parallel factor analysis (PARAFAC). Three fluorescent components were resolved, including two humic-like fractions (microbial-derived C1 and terrestrial-derived C2) and one protein-like fraction (tryptophan-like C3). The winter extreme drought state was associated with CDOM of lower molecular weight, reduced aromaticity, and a stronger terrestrial signature relative to the summer extreme flood state. Building on these contrasts, we developed a Fisher’s linear discriminant model integrating four optical indices -S (275-295), FI (370), SR, and C1:C3- which achieved perfect classification accuracy under leave-one-out cross-validation in discriminating between the two distinct coupled hydro-climatic states (winter extreme drought vs. summer extreme flood). Together, these findings establish a proof-of-concept framework demonstrating that CDOM optical properties can serve as rapid, high-resolution indicators of site-specific hydro-climatic regimes. This approach provides a scalable pathway for monitoring hydro-climatic extremes and their biogeochemical consequences in freshwater systems.

43. 题目: Photoreactivity of dissolved organic matter drives abiotic vivianite formation at sediment–water interfaces
文章编号: N26073002
期刊: Water Research
作者: Shang Yang, Andong Hu, Ruiyuan Wang, Wei Yu, Xiaofeng Wu, Yuefei Huang, Shungui Zhou, Bing Li, Guangqian Wang
更新时间: 2026-07-30
摘要: Vivianite serves as a stable phosphorus sink in anaerobic sediments, playing a decisive role in mitigating internal phosphorus-loading and governing global P geochemical cycling. Typically concentrated at organic-rich sediment–water interfaces, vivianite formation is traditionally viewed through microbial ferric iron reduction, where dissolved organic matter (DOM) acts as a metabolic carbon source or an electron shuttle. However, these paradigms overlook the intrinsic semiconductor-like properties of DOM. Here, we demonstrate a previously unrecognized abiotic pathway whereby a DOM-mediated photoelectric process drives ferric iron reduction and vivianite formation. Ferrous iron rapidly accumulated to 31.74 ± 0.36 mg L-1 within 24 h, and vivianite eventually accounted for 32.7% of the precipitated phosphorus. Mechanistically, light-excited DOM generates transient reducing equivalents that promote ferric iron reduction and phosphate release, while concomitant reactive oxygen species (ROS) consume part of the reducing power and contribute to DOM self-transformation, thereby regulating reaction kinetics. This light-driven mineralization scales systematically with DOM concentration and light intensity, confirming that the photogenerated electrons provide a previously overlooked abiotic route for vivianite formation. Unlike traditional microbially-driven models that rely on organic carbon bioavailability, this light-triggered abiotic pathway bypasses metabolic constraints and directly links solar energy flux to benthic phosphorus immobilization. Our findings reveal that at sunlit sediment–water interfaces enriched in chromophoric DOM, this photoelectric mechanism represents a previously overlooked but critical driver for internal phosphorus cycling, providing a new theoretical basis for predicting and managing phosphorus fate under changing photic conditions.

44. 题目: Sunlight-driven activation of periodate by excited triplet humic acid for efficient microcontaminant abatement
文章编号: N26073001
期刊: Water Research
作者: Bin Zhang, Qiuling Lu, Wenjun Zhang, Haonan Lu, Jun Ma, Tao Yang, Tiangang Luan
更新时间: 2026-07-30
摘要: Humic acid (HA) may inhibit the degradation of contaminants by quenching reactive species in some traditional advanced oxidation processes (AOPs). However, our study found that HA can remarkably enhance the degradation of contaminants by the sunlight-activated periodate (PI) system in practical applications. Herein, a HA-boosted sunlight-activated PI system for contaminant degradation was systematically investigated. The results showed that 2 mgC/L HA increased the degradation efficiency of naproxen (NAP) by about 2.4-fold in the sunlight/PI system. Increased HA or PI concentration enhanced NAP degradation by the sunlight/PI/HA system. Quencher, fluorescence and nitrogen experiments proved that hydroxyl radical (HO•) and ozone (O3) were the main reactive species for the degradation of NAP. Radical probe and O3 experiments confirmed that the increase of pH decreased the quantum yield of PI photolysis, resulting in the decrease of average O3 concentration and the steady-state concentration of HO•, thereby lowering the degradation of NAP. The contributions of HO• and O3 to NAP degradation were determined to be from 65.4% to 81.1% and from 19.3% to 28.1% at pH 4.0–9.0, respectively. The situation of PI decline in different systems proved that the triplet excited state of HA (3HA*) rather than HA•– was the key intermediate species for the accelerated activation of PI, and PI was eventually converted into iodate. The accelerated activation of PI with increasing HA concentration was attributed to the elevated steady-state concentration of 3HA*. Additionally, the applicability of the sunlight/PI/HA system was verified by the degradation of seven different micropollutants. Suwannee River natural organic matter (SRNOM) was also demonstrated to exhibit similar enhancing effects on PI activation as HA under sunlight exposure. Cl– and HCO3– inhibited the degradation of NAP in view of the conversion of HO• into chlorine-containing and carbonate radicals. This work provides a novel insight into improving the solar-photoactivated PI process for water treatment.

45. 题目: Elevated CO2 impacts mercury migration in Chinese paddy soils: Critical roles of pH, dissolved organic matter and the biological pump
文章编号: N26072914
期刊: Journal of Hazardous Materials
作者: Taiting Ding, Zixuan Hu, Xueying Zong, Fuxun Ai, Ying Yin, Hongyan Guo
更新时间: 2026-07-29
摘要: Elevated CO₂ (eCO₂) alters soil biogeochemistry, yet its impact on mercury (Hg) dynamics in low-background paddy soils remains poorly understood. Here, we investigated Hg transformation in 11 Chinese paddy soils under eCO₂ (approximately 600 ppm) using open-top chambers. The results revealed a striking decoupling paradox: while grain methylmercury (MeHg) concentrations often decreased due to growth dilution, the total MeHg accumulation surged significantly (e.g., +656.8% in Yanbian), driven by a biomass-stimulated biological pump. Mechanistically, eCO2 induced rhizosphere acidification and promoted local oxidation. Crucially, Random forest modeling identified tyrosine-like dissolved organic matter (C4) as the dominant predictor for root MeHg uptake, suggesting that protein-like DOM quality may be an important, albeit statistically inferred, modulator of MeHg bioavailability in the rhizosphere. Consequently, eCO₂ accelerates Hg mobilization from clean soils into the food web. Current concentration-based indices (Target Hazard Quotient) mask this intensified flux. These findings highlight that future climate scenarios may activate latent soil Hg risks, necessitating a shift toward flux-based risk assessment frameworks.

46. 题目: Fluorescence signatures track bidirectional DOM-POM interconversion across a mangrove estuarine salinity gradient
文章编号: N26072913
期刊: Marine Chemistry
作者: Lu Yan, Zhihan Yang, Xianjun Xie, Kang Peng, Yamin Deng, Yiqun Gan, Qinghua Li, Yanpeng Zhang
更新时间: 2026-07-29
摘要: Understanding how dissolved organic matter (DOM) and particulate organic matter (POM) are coupled across estuarine mixing zones is central to resolving carbon and nutrient processing in mangrove wetlands. Here we tracked DOM and POM composition and their phase exchange along a salinity gradient in Dongzhai Harbor (Hainan, China) using excitation-emission matrix fluorescence spectroscopy with PARAFAC, complemented by fluorescence indices and partial least squares structural equation modeling (PLS-SEM). Fluorescence intensities of both DOM and POM declined with increasing salinity, consistent with freshwater-seawater mixing and dilution. Four PARAFAC components were resolved in each phase, spanning terrestrial/marine humic-like signals. Terrigenous humic components (C1-C3) decreased seaward, whereas the marine/autochthonous component (C4) increased, indicating a source transition across the mixing gradient. Optical metrics further suggested higher photoreactivity and biodegradability for DOM relative to POM, with implications for nutrient regeneration. Importantly, phase exchange was asymmetric, with a stronger apparent POM-to-DOM linkage than the reverse pathway, suggesting that particulate reworking may replenish the DOM pool, whereas DOM-to-POM transfer may temporarily reduce the immediate bioavailability of dissolved fluorescent components. PLS-SEM supported significant hydrochemical controls on both organic matter composition and DOM-POM exchange pathways. Overall, our fluorescence-based tracking highlights estuarine mixing as a coupled physical-biogeochemical filter that regulates the phase distribution and reactivity of organic matter in mangrove-dominated estuaries.

47. 题目: Extracellular electron transfer improves the regeneration of iron-bound organic carbon in flooding soil
文章编号: N26072912
期刊: Geochimica et Cosmochimica Acta
作者: Yuewei Yang, Jialu Sun, Yun Zhang, Xin Yu, Side Yang, Penghui Li, Xiaojing Li, Shungui Zhou
更新时间: 2026-07-29
摘要: Soil organic carbon (SOC) is protected by combining with iron (Fe) minerals, which supports the stability of soil carbon pool. However, in flooding soils, the microbial dissimilatory Fe reduction can enhance the activation of Fe minerals and the decomposition of Fe-bound organic carbon (Fe-OC). In this study, we found that exposure to enhanced extracellular electron transfer (EET) promoted the reductive dissolution of Fe minerals and the subsequent regeneration of stable Fe mineral, accompanied by the depolymerization metabolism of Fe-OC and microbial reformation. Previously depolymerized SOC was converted into microbial derivatives and combined with the regenerated stable Fe minerals, while increasing the contribution of the “direct Fe protection” pathway (17.2 ± 2.1%) and the “microbial processing” pathway (43.5 ± 7.8%) to Fe-OC. Finally, exposure to enhanced EET increased Fe-OC by 23 ± 4%, mainly related to stable Fe minerals. Here, artificially induced electron transfer is proposed as a strategy to extend the stable carbon pool in soil, though we acknowledge that field-scale scalability, energy costs, and net carbon balance over complete flooding-drainage cycles require further investigation before practical application.

48. 题目: Glomalin-related soil protein in colluvial soils as a proxy for reconstructing millenary changes in landscape and soil health
文章编号: N26072911
期刊: Catena
作者: Axel Werner, Lourdes López-Merino, Joeri Kaal, Cruz Ferro-Vázquez, Oscar Serrano
更新时间: 2026-07-29
摘要: Glomalin-related soil protein (GRSP) is an operationally defined soil organic matter pool that includes a heat shock protein linked to arbuscular mycorrhizal fungi (AMF) living in symbiosis with most vascular plants and plays a key role in soil health. However, the potential of GRSP as a palaeoecological proxy remains unexplored. We analysed the GRSP content in a North-western Iberian colluvial soil profile encompassing the last 14,000 years. We aimed to 1) identify whether GRSP is preserved, and 2) investigate whether GRSP could be used as a palaeoecological proxy after comparing its record with palynological and pedoanthracological records that account for landscape change. The results showed shifting trends in GRSP content and its immunoreactivity with age suggesting that long-term changes in GRSP along the colluvial soil archive might be driven by factors other than post-burial degradation kinetics. Changes in GRSP content at millennial scales were related to changing landscape composition as reconstructed by palynology and anthracology. GRSP content was larger than average when vegetation consisted in mature woodland formations. On the other hand, GRSP decreased during phases of vegetation change: first, from the birch open formation to the oak woodland at the Pleistocene/Holocene climate transition; and second, from the oak woodland to a heathland due to Late Holocene anthropogenic impact. While the GRSP record in this colluvial soil alone cannot provide information regarding changes in the composition of vegetation, it delivers a broad overview of major landscape shifts related to large climate- and human-induced changes in vegetation. Hence, GRSP analysis can be a time- and cost-efficient proxy for identifying long-term landscape changes that impacted soil ecosystem's health in colluvial soils. The results obtained highlight the need of further GRSP research on other environmental archives, including lake and mangrove sediments, as well as peat, colluvial and seagrass soils.

49. 题目: Spatial heterogeneity and controls of sedimentary organic carbon distribution in different types of coastal wetland
文章编号: N26072910
期刊: Catena
作者: Tianyi Nie, Kai Zhou, Fan Zhang, Xiaohui Zhai, Wenpeng Li, Huawei Wang, Chengpeng Sun, Zhenjun Kang, Xupeng Hu, Wenfeng Ning, Yifan Qi, Jiuzhou Chen, Xinxin Li
更新时间: 2026-07-29
摘要: Large-scale assessment of sedimentary organic carbon (SOC) storage in blue carbon ecosystems provides valuable benchmarks, yet averaging over regional heterogeneity in data synthesis can bias upscaling. To better understand the regional heterogeneity in SOC distribution and its controls across different coastal wetland types in subtropical China, Shenzhen was selected as a regional model with four coastal wetland types based on geomorphology: coastal mangrove, semi-enclosed mangrove, spotted mangrove, and tidal flats. The results showed distinct contents and distribution patterns in soil texture, bulk organic carbon properties, and the lignin-phenol organic biomarker across wetland types. Varied organic carbon sources primarily controlled SOC in coastal mangrove sediments, but soil texture became the primary factor in spotted mangrove and tidal flat sediments. In semi-enclosed mangrove, sources, vegetation, and soil texture jointly affected SOC characteristics. The SOC storage in mangrove ecosystems was reassessed at 28.0 Gg C, which is 1.5–2 times the previous estimates. The SOC storage in tidal flats was first assessed at 4.7 Gg C. The spatial heterogeneity underscores the importance of regionally balanced data when upscaling to large-scale assessment, especially given the geomorphologically diverse wetland types.

50. 题目: Advancing soil organic matter and mineral characterization by mid-infrared spectroscopy using spectral subtraction
文章编号: N26072909
期刊: Geoderma
作者: Marcus Schiedung, Andrew J Margenot, Stefan Dultz, Mike C Rowley
更新时间: 2026-07-29
摘要: The composition of soil organic matter (OM) and mineral phases is essential for soil functions. Diffuse reflectance Fourier transform mid-infrared (DRIFT-MIR) spectroscopy allows rapid characterization of soils, but its effectiveness is often limited by the complex interactions and interferences between OM and mineral phases. This study systematically evaluated spectral subtraction after OM removal by thermal dry oxidation (loss on ignition (LOI)), chemical wet oxidation using sodium hypochlorite (NaOCl), and hydrogen peroxide (H2O2). We derived sample specific subtraction factors to determine the mineral- and OM-enhanced spectra of each sample. Six soil samples with contrasting textures (clay, loam and sand) and organic carbon content (0.8–6.8%) as well as the presence of inorganic carbon (up to 0.5% carbon) were analyzed. Our results showed that LOI at 550°C for 60 min was most effective for removing OM (>98% of initial organic carbon). In contrast, NaOCl and H2O2 resulted in lower OM removal (72–95% of initial organic carbon) and created artifacts in the mineral- and OM-enhanced spectra. In a spiking test, milled and dried summer wheat root litter was added to a model mineral soil composed of six phyllosilicate clay minerals, calcium carbonate and goethite. For LOI and NaOCl, dehydroxylation and oxidation reactions of the mineral phase were clearly traceable, but LOI proved most suitable for recovering the original OM and mineral spectral signatures. Our study shows that spectral subtraction is an efficient approach to disentangle OM and mineral spectra composition from complex soil matrices by DRIFT-MIR. We provide guidance on how spectral subtraction can be applied to different soil types to rapidly investigate OM dynamics and mineral composition.

51. 题目: Full-volatility characterization of ROC emissions from industrial coatings reveals a mass–hazard decoupling driven by emerging toxicants
文章编号: N26072908
期刊: Journal of Hazardous Materials
作者: Zhihao Zhang, Di Wang, Jingnan Hu, Dongting Wei, Wendong Ge, Jinmin Zhao, Jiangtao Xing
更新时间: 2026-07-29
摘要: Industrial volatile chemical products (VCPs), particularly those used in industrial coating applications, have emerged as major sources of reactive organic carbon (ROC) emissions with implications for atmospheric chemistry and human health. However, coating-related ROC emissions remain poorly constrained, limiting assessment of their environmental and health impacts. Here, we characterized full-volatility ROC emissions from representative industrial coating processes across gas and particle phases and estimated China’s national ROC emissions from downstream coating processes at approximately 5.31 Tg yr⁻¹ in 2019. Volatile organic compounds (VOCs) dominated the characterized ROC mass in the high-volatility range, with aromatics (35.6%) and cyclic alkanes (20.4%) as major hydrocarbon groups, whereas oxygenated and functionalized organics increased at lower volatility ranges. However, emission mass alone did not reflect health relevance. Species prioritized by quantitative lifetime cancer risk (LCR) and hazard index (HI) assessment represented approximately 22.6% of the characterized ROC mass but dominated the calculated risk indicators. The top two cancer-risk contributors, 1,2-dichloroethane and trichloroethylene, accounted for 96.3% of the summed LCR while representing only 5.07% of the characterized ROC mass. In addition, a recurrently detected emerging-pollutant subset, including polycyclic aromatic hydrocarbons (PAHs), phthalates, phenolic antioxidants, and cyclic siloxanes, represented only ∼0.22% of the characterized ROC mass but was prioritized by complementary toxicity screening. These findings indicate a pronounced mismatch between emission mass and health hazard in coating-related ROC emissions, suggesting that conventional mass-based VOC metrics may underestimate health-relevant risks. A hazard-prioritized, tiered management framework is therefore proposed to support risk-oriented mitigation and more comprehensive full-volatility ROC regulation.

52. 题目: Activation of periodate driven by the synergistic interaction between inherent soil Fe and organic matter for adiazine degradation: Mechanisms, soil-type effects, and soil property changes
文章编号: N26072907
期刊: Journal of Hazardous Materials
作者: Yue Zhang, Caixia Yan, Yabing Chen, Yuyan Liu, Mingjun Ding, Peng Wang, Haofeng Liu, Minghua Nie
更新时间: 2026-07-29
摘要: Periodate (PI) has been extensively utilized for the degradation of recalcitrant organic pollutants in aqueous environments. In contrast, its application in soil remediation is still limited. The critical unknowns notably encompass whether, how, and to what extent inherent soil constituents activate PI. Here, we firstly demonstrate that inherent soil components, particularly Fe species and soil organic matter (SOM), can effectively activate PI without external catalysts. Using adiazine (ADZ) as a model, PI-mediated oxidation was systematically evaluated in 10 representative soils. Correlation analyses identified free Fe oxides (Fef) as the dominant PI activators, accounting for 79.06% of the overall ADZ degradation and driving the formation of reactive species (RS), including 1O2 (dominant), •IO3, •IO4, and •OH. SOM exhibited a component-dependent dual effect, promoting ADZ degradation in SOM-poor soils (33.77%) but inhibiting it in SOM-rich soils (−18.87%). Specifically, soluble microbial by-product-like and humic acid-like components facilitated RS generation, whereas aromatic protein and fulvic acid-like components suppressed RS generation by competing for PI. Spectroscopic analyses confirmed that PI treatment preserved soil structural integrity with only minor alterations. 11 transformation products and 3 degradation pathways were identified, and ecotoxicity analysis and phytotoxicity tests demonstrated reduced post-remediation toxicity and recovery of plant growth. Cl−, NO3−, and humic acid had no significant impact, whereas low concentration Fe3+ and Mn2+ enhanced oxidation. Overall, this study elucidates how inherent Fe oxides and SOM regulate PI activation in soils, providing a theoretical basis for optimizing in-situ PI oxidation for antibiotic-contaminated soils.

53. 题目: Risks of mercury release from disturbance of blue carbon ecosystems
文章编号: N26072906
期刊: Earth-Science Reviews
作者: Fan Zhang, Jingrou Hu, Ana Carolina Ruiz-Fernández, Christian J Sanders, Xinxin Li, Ruotong Chen, Kunshan Bao, Bigyan Neupane, Aidah Baloch, Yanhui Zheng, Oscar Serrano
更新时间: 2026-07-29
摘要: Blue carbon ecosystems (BCEs) function as dual repositories of organic carbon and legacy contaminants. While BCEs are recognized carbon sinks, their role as mercury (Hg) sinks and the risk of their conversion into sources due to human and climatic disturbances remain unexplored. This review synthesizes current knowledge on the drivers and risks of contaminant remobilization from threatened BCEs, with a primary focus on mercury. We explore how natural and human disturbances influence Hg storage, release, and bioavailability, while evaluating the risks posed to ecosystems and human health. Through a three-level meta-analysis, we show that physical disturbance remobilizes approximately 54% (95% CI: 8% to 77%) of sediment-bound metals from coastal sediments. Applying this fraction to published BCE Hg stock and loss-rate data, we derived a first-order estimate of 26 (95% CI: 3.9 to 40.8) Mg of total mercury (THg) released annually from BCE degradation and loss worldwide, a flux that offsets approximately 60% of annual BCE Hg burial capacity. The proportion of this bulk THg flux subsequently converted to bioavailable methylmercury (MeHg) depends on local redox conditions and microbial activity, and remains an important uncertainty. We organized the biogeochemical cascade linking sediment disturbance to ecological exposure into two temporally overlapping phases, an immediate physical and chemical release and a delayed biogeochemical exchange, and identified compound disturbance amplification as a critical but previously unrecognized mechanism by which sequential stressors produce non-additive Hg release. Additionally, we identified global BCE-derived Hg risk hotspots through a five-dimensional, evidence-weighted framework applied to 17 UN M49 sub-regions, classifying East Asia, Latin America and the Caribbean, Sub-Saharan Africa, and three Pacific Island sub-regions as Tier 1 high-risk priorities where multiple risk dimensions converge. These findings reframe BCE conservation as simultaneously a carbon, contaminant, and food-security imperative, underscoring the need for legacy-Hg governance alongside atmospheric emission controls under the Minamata Convention.

54. 题目: The unseen architects: Unraveling soil faunal necromass contribution to soil carbon sequestration
文章编号: N26072905
期刊: Soil Biology and Biochemistry
作者: Md. Zulfikar Khan, Carlos A Aguilar-Trigueros, Sten Anslan
更新时间: 2026-07-29
摘要: Given the sheer scale of faunal life present in soils, the remains of these organisms in their afterlife represent an important pool of soil organic matter (SOM). Recently, Lejoly et al. (2026) highlighted the importance of faunal contributions in SOM, including inputs from this “faunal necromass”, and calls for explicit measurement of this carbon pool. While we agree with this call, however, we raise the issue that no methods have been developed to explicitly quantify it. This oversight not only limits the measurement of this carbon pool, but also biases estimates of fungal necromass. That is, the widely used chitin-derived glucosamine as a fungal necromass biomarker is found in both fungal and faunal dead tissues. This “chitin conundrum” creates a major limitation for estimating of necromass-derived soil carbon pools dynamics. Integrating compound-specific isotope analysis, metaproteomics, high-resolution mass spectrometry and faunal-specific molecular markers with experimental soil food-web approaches could resolve this limitation and reveal the true role of soil fauna in carbon cycling dynamics.

55. 题目: Sulfur-driven hidden carbon flux enables reductive dechlorinating in sulfur-metabolism biofilm
文章编号: N26072904
期刊: Chemical Engineering Journal
作者: Zhou-Yang Li, Han-Bing Xiao, Min Li, Xue-Ning Zhang, Kun Zheng, Ai-Jie Wang, Yi-Lu Sun
更新时间: 2026-07-29
摘要: The co-occurrence of nitrate and chlorinated phenols in industrial wastewater presents a significant challenge for simultaneous removal under carbon-limited conditions. This study evaluates a sulfur-metabolism biofilm reactor for the concurrent removal of nitrate and 2,4,6-trichlorophenol (2,4,6-TCP) without external organic carbon as electron source. A 180-day continuous-flow operation demonstrated efficient nitrate reduction (>90%) and effective 2,4,6-TCP dichlorination (∼80%) to 2,4-dichlorophenol (2,4-DCP) and 4-chlorophenol (4-CP). Batch experiments revealed that increasing nitrate concentrations enhanced 2,4,6-TCP dechlorination rates. 16S rRNA gene sequencing and qPCR indicated the enrichment of sulfur-oxidizing bacteria (e.g., Thiobacillus) and potential dechlorinators (e.g., Chloroflexota), along with elevated levels of dehalogenation gene (cprA). Metagenomic analysis suggested that sulfur oxidizers mediate CO2 fixation and downstream central carbon metabolism. This process may generate low-molecular-weight metabolites such as formate and butyrate, which could serve as electron donors for potential dechlorinators (Chloroflexota). Follow-up nitrate-resupplemented batch tests confirmed that formate and butyrate accumulation was nitrate-dependent and declined upon 2,4,6-TCP addition, indicating their consumption during reductive dechlorination. These findings revealed a syntrophic linkage between autotrophic denitrifiers and organohalide-respiring bacteria, thereby facilitating simultaneous nitrogen elimination and transformation of recalcitrant organics under carbon-limited conditions. This study highlights a promising strategy for sustainable treatment of mixed contaminants via sulfur-metabolism biofilm.

56. 题目: Biomass-burning smoke water-soluble organic matter reverses ferrihydrite colloid-inhibited mobility of Cd2+ through saturated porous media via interface fractionation and selective binding
文章编号: N26072903
期刊: Chemical Geology
作者: Bin Wang, Nan Yang, Kunyu Wen, ZhiWei Chen, Boyun Zheng, Yanbin Ma, Li Zhang, Zhichong Qi
更新时间: 2026-07-29
摘要: Biomass burning events release large amounts of pyrogenic dissolved organic matter (BBS-WSOM) into terrestrial ecosystems, where it interacts with iron oxides and trace metals. However, how the molecular heterogeneity of BBS-WSOM governs colloid-facilitated metal transport remains poorly constrained. Here, we combined column transport experiments with multispectral analysis to elucidate how BBS-WSOM modulates the co-mobility of ferrihydrite (Fh) colloids and Cd2+ in saturated porous media. We found that humic-like components with higher aromaticity and hydrophobicity were preferentially retained on sand surfaces, whereas protein-like components remained largely in the aqueous phase. Protein-like components were the primary agents responsible for Cd2+ complexation, thus facilitating Cd2+ mobility. Although Fh colloids alone suppressed Cd2+ transport, the presence of BBS-WSOM not only neutralized this suppression but further enhanced Cd2+ mobility in the ternary system (Cd2+ + Fh + WSOMs) compared to the binary system (Cd2+ + WSOMs). This counterintuitive enhancement arose from molecular fractionation at the Fh-water interface: Fh preferentially adsorbed humic-like components, enriching the aqueous phase with protein-like components that bound Cd2+ more effectively. These findings reveal that the trade-off between humic-like and protein-like components within pyrogenic DOM critically controls the direction and magnitude of colloid-mediated metal transport. Our study provides mechanistic insights into how wildfire-derived or burning-derived DOM alters subsurface Cd geochemistry, with implications for the coupled cycling of carbon, iron, and trace metals in fire-impacted terrestrial environments.

57. 题目: Insights into iron-enhanced denitrification coupled with antibiotic resistant genes control in biochar-based biofiltration systems
文章编号: N26072902
期刊: Water Research
作者: Chen Wang, Lecheng Wei, Peijin Cheng, Xuan Fan, Xiangyang Xu, Liang Zhu
更新时间: 2026-07-29
摘要: In biofiltration (BF) systems, biochar can enhance pollutant removal by promoting biofilm formation. Its abundant pore structure can also sequester antibiotics away from microbial cells, thereby reducing its bioavailability and accumulation of antibiotic resistance genes (ARGs). However, dense biofilms favor horizontal ARG transfer, especially among denitrifying bacteria, which are prone to stress under low influent C/N conditions. In this study, a strategy combining iron minerals was proposed to alleviate the ARG accumulation in BF systems. Compared with magnetite, goethite and siderite released Fe2+ through microbial dissimilatory iron reduction and chemical dissolution respectively, thereby driving iron‑autotrophic denitrification and enhancing the activity of electron‑transfer mediators (cytochrome c and Fe-S proteins). As a result, the level of nitrosative stress was reduced with significant downregulation of related genes (hmp, hcp, norR, and etc.), which was a driving force for conjugative transfer of ARGs. Specifically, the excessive accumulation of tryptophan and shortage of methionine were thus alleviated, which contributed to the regulation of global repressor gene expression and the mitigation of ARG conjugative transfer. With the combination of goethite or siderite in BF systems, the abundance of resistance genome in biofilm exhibited a reduction of 52.68 ± 3.80% and 41.26 ± 4.20%, respectively, which could effectively reduce the environment-ecological risk of antibiotic and ARGs.

58. 题目: Iron as a driver of organic carbon fate in permafrost regions
文章编号: N26072901
期刊: Nature Geoscience
作者: S Opfergelt, E M Herndon, C Bryce, A J Barker, C Hirst
更新时间: 2026-07-29
摘要: Iron (Fe) and its biogeochemical interactions with organic carbon (OC) exert critical controls over carbon storage and water quality across Arctic and sub-Arctic landscapes. Permafrost thaw affects Fe–organic carbon interactions by exposing thawed material and driving shifts in hydrologic regimes. Here we propose a conceptual framework describing how Fe–OC interactions respond to permafrost thaw and the implications for global carbon cycling. The framework builds on current understanding of hydrologically driven processes that are altered by permafrost thaw, including microbial Fe reduction that influences OC decomposition and carbon emissions; Fe cycling through redox transformations and sulfide oxidation; dissolution and reprecipitation of Fe–OC assemblages; and Fe export to river networks. We put forward four testable hypotheses—on topics from Fe supply to its role in soil OC storage and transfer to rivers—to advance understanding of the coupled environmental controls on pore-scale reactions (that is, microscale reactions at mineral–water–microorganism interfaces) that are central to global Fe–OC cycling. Our framework highlights how soil-profile- and landscape-scale processes, such as hydrologic connectivity and redox dynamics, regulate pore-scale Fe–OC reactions.

59. 题目: Inefficient sinking and burial of phytoplankton-derived organic carbon in a large shallow eutrophic lake: The case of Lake Taihu and beyond
文章编号: N26072815
期刊: Organic Geochemistry
作者: Yanhong Xu, Jiali Pang, Guangwei Zhu, Yuxin He, Jinglu Wu, Yongge Sun
更新时间: 2026-07-28
摘要: The impact of eutrophication-induced phytoplankton blooms on organic carbon (OC) burial in lake systems largely depends on OC loss within the water column and surface sediment, a process that remains poorly constrained, particularly in shallow lakes. In this study, phytoplankton-related n-heptadecane (n-C17) is introduced to quantify the sinking and burial efficiencies of phytoplankton-derived OC in Lake Taihu, East China, a typical large shallow eutrophic lake. The results show that only 2.3 ± 2.2% of primary productivity can be buried in the sediments in the bloom season due to low sinking (27.2 ± 2.2%) and burial (8.5 ± 8.1%) efficiencies. Inherently high bioavailability of phytoplankton-derived OC and elevated temperatures collectively lead to low sinking efficiency in Lake Taihu, even within shallow lakes. Extended oxygen exposure in large shallow lakes accelerates microbial decomposition, resulting in the massive OC loss during transport from the water body to surface sediments and further leading to an inefficient OC burial in large shallow lakes. By synthesizing published data, we demonstrate that lake morphology predominantly regulates how eutrophication affects OC burial across global lakes. Compared to small and deep ones, large subtropical shallow lakes usually have inefficient OC burial. Our findings advance our understanding and prompt a reassessment of the contribution of lake eutrophication to the global carbon cycle, and the method developed here could be used in the field of limnology with respect to the assessment of OC burial.

60. 题目: Carboxyl-Fe and phosphonate-Fe interactions control the redistribution of organic phosphate during ferrihydrite transformation
文章编号: N26072814
期刊: Chemical Geology
作者: Xiaofan Pan, Zhenzhen Zhao, Xin Huang, Ning Deng
更新时间: 2026-07-28
摘要: Transformation of poorly crystalline ferrihydrite (Fh) into crystalline phases is a critical process controlling mineral stability and element cycling. However, the molecular mechanisms by which organic phosphorus (OP) compounds influence Fh transformation remain unclear. Here, we investigated the effects of three representative OPs with distinct functional groups—triethyl phosphate (TEP), 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC), and 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP)—on Fh transformation. Results showed that TEP, containing only a phosphate group, showed negligible adsorption and minimal effect, whereas PBTC and HEDP strongly bound to Fh via carboxyl and phosphonate groups, respectively, significantly slowing transformation. Synchrotron-based FTIR indicated that PBTC predominantly bound to Fh through strong Fe-carboxyl interactions, while HEDP mainly formed Fe-phosphonate complexes on Fh surfaces. The stronger carboxyl-mediated surface complexation of PBTC resulted in persistent association with the solid phase throughout the transformation process. In contrast, HEDP exhibited dynamic redistribution during Fh transformation, characterized by initial release followed by re-immobilization. Geochemical modeling showed that the complexation of HEDP with aqueous Fe3+ favored the incorporation of Fe3+-HEDP complexes into growing secondary mineral phases, leading to HEDP refixation. These results reveal that OP functional groups govern both Fe mineral stability and OPs fate, providing mechanistic insights into organic ligand-mediated Fe mineral evolution.