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681. 题目: Mineral Stabilization Slows Losses of Peatland Carbon Following Long‐Term Drainage for Agriculture
文章编号: N26071005
期刊: Global Change Biology
作者: Katy J Faulkner, Katerina Georgiou, David A Coomes, Philippa Ascough, Anna Basford, Rodney G O Burton, Romy Copley, Emma Keerberg, Alanie Lapina, Kimber Moreland, Christopher Evans, Ross Morrison, Adam F A Pellegrini
更新时间: 2026-07-10
摘要: Cultivated peatlands are a major CO 2 emission source, but the processes that regulate the decomposition of drained peat are debated, especially as drained peat becomes increasingly shallow. Many cultivated peatlands are underlain by a mineral soil layer. Surface subsidence, oxidation and tillage reduce the peat thickness, which intermixes peat with minerals as peat is lost. A key question is whether this mixing can reduce emissions by making soil organic carbon (SOC) more stable by transforming particulate organic carbon (POC)—which dominates the carbon stock in deep drained peatlands and is readily accessible to microbial decomposers—into mineral‐associated organic carbon (MAOC), which is less accessible to decomposers. To explore this question, we surveyed ten sites across the East Anglian Fens in England, a once extensive (~3900 km 2 ) peatland landscape that has been drained for cultivation since the mid‐seventeenth century. We used variation in cultivation to establish a peat loss gradient to evaluate how topsoil SOC (0–40 cm) and its forms change as peat is lost. As the peat was lost, the soils became rich in minerals (rising from 46% to 88% silt+clay content), resulting in an initial 11‐fold rise in newly‐formed MAOC, but a monotonic decline and near‐total loss of POC. POC turnover times were 3158 ± 62 years, indicative of peat, and POC was always older than MAOC; consequently, microbially‐processed peat along with gradual contributions of recently fixed carbon were sources of MAOC. A four‐month laboratory incubation showed that the MAOC:POC ratio was negatively correlated with respiration. We conclude that long‐term carbon retention via MAOC formation has the potential to reduce carbon loss from degraded, mineral‐mixed peatlands. However, because this MAOC pool is itself vulnerable to loss under continued agricultural drainage, this mechanism is expected to slow rather than halt long‐term soil carbon loss from drained peatlands.

682. 题目: Impact of Salinity on Straw Conversion Into Different Soil Organic Carbon Fractions: Evidences From a 13 C ‐Labeling Incubation Experiment
文章编号: N26071004
期刊: Land Degradation & Development
作者: Wenjun Xie, Cailing Shi, Jing Zhang, Haibo Zhang, Yanhong Dong, Lei Xu, Yinglu Tao, Yue Wu, Gaoqi Li, Lichang Zhang
更新时间: 2026-07-10
摘要: Although straw is widely used to ameliorate saline soils, the impact of salinity on straw conversion into soil organic carbon (SOC) fractions remains unclear. Our aim was to explore how soil salinity affected straw conversion into SOC. A 180‐day soil incubation with 13 C‐labeling maize straw was conducted to investigate straw conversion into free particulate organic carbon (fPOC), occluded particulate organic carbon (oPOC), and mineral‐associated organic carbon (MAOC) under different salinity levels. Four soil salinity levels were arranged: 3 (LS), 5 (MS), 10 (HS), and 15 g kg −1 (SS), and 5.0% of 13 C‐labeling straw was added to each treatment. Straw conversion into fPOC was significantly positively associated with salinity level, while straw‐derived oPOC and MAOC significantly decreased with increasing salinity ( p < 0.05). This clearly indicated that high salinity could favor fPOC accumulation, but lower the capability of soil carbon sequestration. Meanwhile, C/N ratio of SOC significantly decreased with salinity rising ( p < 0.05), reflecting that the composition of SOC pool was obviously affected by salinity. Furthermore, soil dehydrogenase, cellulase, and β ‐glucosidase activities decreased significantly with salinity rising ( p < 0.05), suggesting that salinity inhibited microbially derived SOC formation during straw decomposition. Overall, our findings first discover the specific influence of soil salinity on straw conversion into SOC, which can provide a more comprehensive understanding of the capability of soil carbon sequestration under different saline conditions.

683. 题目: Dominant Microbial, Aggregate, and Mineral Pathways of SOC Quantity and Lability: Insights From SOC Functional Groups
文章编号: N26071003
期刊: European Journal of Soil Science
作者: Mengrou Li, Xianfeng Zhang, Xiuli Xin, Wenliang Yang, Anning Zhu
更新时间: 2026-07-10
摘要: Organic amendments are widely used to restore soil carbon (C) in Mollisols of croplands, yet how microbial‐, aggregate‐, and mineral‐associated processes are related to soil C quantity and lability remains unclear. Here, we conducted a 3‐year field experiment in Mollisols of Northeast China to evaluate manure, biochar, and their co‐application effects on soil organic carbon (SOC), easily oxidizable organic C (EOC), SOC functional group composition, microbial network properties, aggregate‐associated C, and mineral‐associated C. Across the 3 years, biochar increased SOC, manure enhanced EOC, and co‐application increased both. These divergent C responses were accompanied by changes in SOC functional groups, with manure enriching carbohydrate‐derived labile fractions and biochar increasing SOC hydrophobicity. Random forest analysis identified hydrophobicity, Aryl C, and Carboxyl C as key predictors of SOC, whereas O‐alkyl and Di‐O‐alkyl C best explained EOC variation. Microbial co‐occurrence network properties were statistically associated with SOC hydrophobicity and Di‐O‐alkyl C, while macroaggregate‐associated C and mineral‐associated C fractions were positively linked to SOC hydrophobicity. Partial least squares path modeling further suggested that SOC accumulation was associated with increases in Aryl C and Carboxyl C, with stronger positive contributions from macroaggregate formation than microbial network properties. In contrast, microbial co‐occurrence network complexity showed a negative correlation with O‐alkyl and Di‐O‐alkyl C, indicating a potential linkage between network structure and labile C dynamics. Overall, our findings show that manure‐biochar co‐application achieved concurrent increases in SOC and EOC, accompanied by greater aggregate‐ and mineral‐associated C fractions and lower microbial co‐occurrence network size. This integrated evidence highlights manure‐biochar co‐application as a practical strategy for improving both soil C storage and labile C availability in Mollisols.

684. 题目: Organic matter controls rare earth element hyper-enrichment in Pacific deep-sea bioapatite
文章编号: N26071002
期刊: Geochimica et Cosmochimica Acta
作者: Xijiao Liao, Dengfeng Li, Simon W Poulton, John R Reinfelder, David Chew, Yu Fu, Yongjia Liang, Zhengkun Li, Jinzhou Peng, Xiaoming Sun
更新时间: 2026-07-10
摘要: Bioapatite is a predominant sink for rare earth elements (REE) in global deep-sea sediments, where the REE accumulate either via organic matter remineralization or Fe–Mn (oxyhydr)oxide dissolution. While the sequestration of REE into bioapatite has been extensively documented, the mechanistic pathways governing REE transfer from these carrier phases to bioapatite during diagenesis remain poorly constrained. This limits understanding of REE hyper-enrichment in deep-sea sediments, and impacts the reliability of REE signatures in bioapatite as palaeoceanographic tracers. In this study, we elucidate the mechanisms of REE hyper-enrichment from marine porewaters into bioapatite in the presence of Fe–Mn (oxyhydr)oxides and organic matter, using a combination of adsorption experiments integrated with micro-X-ray absorption fine structure (μ-XAFS), X-ray absorption near edge structure (XANES), and extended X-ray absorption fine structure (EXAFS) analyses. Results demonstrate that bioapatite can rapidly adsorb REE from a simulated porewater environment (equilibrium time <1 h) via the formation of stable inner-sphere complexes. XANES and EXAFS evidence further reveals that these complexes are strongly coordinated by PO43− groups, as exemplified by Y3+ with well-defined coordination shells: Y–O (2.37 Å), Y-P1 (3.50 Å), and Y-P2 (3.71 Å), which maintains long-term REE retention in bioapatite. Furthermore, we show that organic matter regulates REE cycling through coupled direct and indirect pathways: (1) enhancing short-term REE adsorption onto bioapatite through complexation with CO and O–H bonds, accounting for 79–94% of initial REE uptake; and (2) indirectly promoting long-term REE sequestration by driving the reductive dissolution of Fe–Mn (oxyhydr)oxides, which enhances the REE supply to porewaters for subsequent adsorption by bioapatite. We therefore propose that organic matter plays a central role in controlling REE hyper-enrichment by coupling REE sources (organic matter and Fe–Mn (oxyhydr)oxides) with long-term retention in bioapatite during early diagenesis. This explains the spatial variability in REE enrichment observed across Pacific sediments, and establishes a refined framework for evaluating the early diagenetic alteration of REE signatures.

685. 题目: Enhancing CO2 adsorption in beach-cast seaweed-derived biochar by fast pyrolysis temperature tuning and simple water-washing
文章编号: N26071001
期刊: Journal of Environmental Chemical Engineering
作者: Yu Zhang, Kelly Hawboldt, Stephanie MacQuarrie
更新时间: 2026-07-10
摘要: Beach-cast brown seaweed is rapidly accumulating along coastlines worldwide, overwhelming ecosystems, disrupting marine life, and creating serious challenges for coastal communities and tourism. Despite the scale of this growing problem, it remains an underused biomass that could be converted into valuable carbon materials, offering a way to address an increasingly urgent environmental issue. This study investigated pyrolysis with simple water washing to enhance the physicochemical properties and CO2 adsorption performance of seaweed-derived biochar. A central composite design was applied to evaluate the effects of pyrolysis temperature (258–600 °C) and solids residence time (1–29 min) on product distribution and biochar characteristics. Pyrolysis temperature was identified as the dominant factor impacting biochar yield, carbonization, and pore development. Subsequent water washing removed inorganic mineral deposits and improved access to previously blocked micropores, leading to enhanced CO2 capture performance. As a result, washed biochars produced at 500–600 °C achieved CO2 adsorption capacities of 2.18–2.42 mmol/g at 273 K and 100 kPa without chemical activation. The results demonstrate that temperature-controlled pyrolysis combined with water washing provides a simple and eco-friendly strategy for converting problematic beach-cast seaweeds into effective carbon capture materials while supporting coastal biomass valorization.

686. 题目: Biochar and Green Compost Used in Cascade: The Link Between Circular Horticulture and Soil Improvement
文章编号: N26070906
期刊: European Journal of Soil Science
作者: Bart Vandecasteele, Jarinda Viaene, Rianne Visser, Amine Lataf, Ann Cuypers, Dries Vandamme
更新时间: 2026-07-09
摘要: Carbon‐rich biomass such as compost or biochar can be used for a variety of soil applications including C sequestration or targeted improvement of soil cation exchange capacity, organic carbon (C) and pH. The use of exogenous organic matter rich in C is expected to increase, increasing the risk of biomass shortages. Use of materials in cascade is one strategy to avoid competition for C‐rich biomass. Green composts and wood‐based biochars are examples of renewable materials, most often applied directly to soils, that can also be used as bulk replacement for peat in horticultural substrates. After use in cultivation, these horticultural substrates can again be used as a soil improver, either directly or after further processing into compost or biochar. Three cases were studied: (1) the sequential use of biochar in a horticultural cascade, (2) comparison of green composts vs. spent horticultural substrates as organic soil improver, and (3) comparison of wood‐based biochars with biochars made from either spent horticultural substrates or various sources of biomass as organic soil improver. For Case 1, the use of biochar in cascade, starting with growing media containing 10% v/v wood‐based biochar, showed an added value for exogenous organic matter used as soil improvers: the addition of wood‐based biochar in the growing medium resulted in a higher C content in the spent horticultural substrates. The high C/P ratio was maintained in the spent growing media, even after composting or conversion into biochar. In Case 2, spent growing media containing green compost had a higher added value as soil improver and source of stable C than the pure green compost: these materials had a higher C content and higher biological stability and thus a lower oxygen uptake rate and/or C mineralization rate than pure green compost. Their microbial biomass remained high, at levels comparable to green compost. For Case 3, biochars produced from spent growing media clearly differed from biochars made from wood, bark, or straw‐like fibers in terms of nutrients, organic and inorganic C content, and short‐term biological stability. In particular, the biochars made from spent growing media had a higher acid‐buffering capacity due to their higher inorganic C content. Biochars from spent growing media may have a lower biological stability when produced at 400°C–450°C in comparison to biochars produced at higher temperatures, as well as biochars produced from wood. A high risk of N immobilization was observed in the biochars produced from spent growing media, similar to the wood‐based biochars and the biochars produced from bark or straw‐like fiber. In conclusion, this study indicated that (a) using biochar in a horticultural cascade resulted in exogenous organic matter for use as soil improver with a higher C content and biological stability, (b) using green compost in a horticultural cascade resulted in exogenous organic matter with a higher C content and higher C stability than for pure green compost and (c) converting spent growing media with green compost into biochar results in biochars with higher acid‐buffering capacity but lower organic C content and biological stability than for biochars produced from wood. This study provided specific insights into the added value of organic soil improvers from the horticultural cascade.

687. 题目: Food Waste Derived Biochar via Pyrolysis: Properties, Contaminant Sequestration Mechanisms, and Environmental Applications.
文章编号: N26070905
期刊: Environmental Research
作者: Muhammad Waqas, Abdul-Sattar Nizami, Osman Atilla Arikan, Dilek Beyazli, Ali Temiz, Javed Nawab, Muhammad Naqvi, Mohammad Rehan
更新时间: 2026-07-09
摘要: The novel technique of biochar production from food waste (FW) through pyrolysis is a proactive step towards materialising the circular economy. This review provide a detail insights on the successful utilisation of FW for biochar production and its subsequent environmental applications, along with efficiencies and mechanisms in the removal of various pollutants from wastewater. The chemical transformation during FW pyrolysis assists the resultant biochar with unique physiochemical characteristics, including structure formation, porosity, alkalinity, functional groups, polarity, cation exchange capacity and carbon structure that contribute to the efficient removal of pollutants. Based on the organic-rich nature, detailed discussions have been made on how FW could be an ideal feedstock for pyrolysis as compared to other bio-waste. Moreover, the impacts of pyrolysis temperatures on the characteristics, variations in the removal efficiencies and interactions of biochar with pollutants have been discussed. The suitability of FW biochar for environmental applications is its stability for subsequent usage without losing activity and production of secondary pollutants or by-products, as compared to other technologies. However, despite the promising benefits, FW to biochar technology is still in infancy and prone to several challenges, including scalability due to intrinsic heterogeneity, high moisture that sometimes requires an additional step of drying and grinding and variations in the physicochemical characteristics that impact the economic feasibility, scalability and end-use marketability. Hence, detailed studies on techno-economic analysis in integration with advances in FW to biochar production, applications as adsorbent, stability, and reusability after treatment to fully explore the comparison with other available similar materials.

688. 题目: Responses of Soil Carbon Release to Freeze–Thaw Cycles Mediated by Carbon Availability at Regional and Global Scales
文章编号: N26070904
期刊: Global Change Biology
作者: Siyu Wang, Shuqi Qin, Yan Yang, Leiyi Chen, Luyao Kang, Yuanhe Yang
更新时间: 2026-07-09
摘要: Soil freeze–thaw cycles (FTCs) are widespread across mid‐ to high‐latitude and high‐altitude regions, with particularly high frequency in permafrost areas where they can enhance soil carbon release and potentially accelerate climate warming. However, the response of soil carbon release to FTCs and its determinants at the regional scale remain unclear due to the lack of direct experimental evidence. Here, based on topsoil samples along a 1000‐km transect across the Tibetan permafrost region, we conducted a freeze–thaw microcosm experiment (5 cycles of 1‐day freezing and 3‐day thawing) to investigate patterns and predictors of FTC‐induced soil carbon dioxide (CO 2 ) release. The results revealed that FTCs significantly increased soil CO 2 release by 20% ± 2% relative to the thaw‐only control across all cycles. This response was primarily driven by soil carbon availability rather than microbial properties. Soils with higher carbon availability, as indicated by initially (prior to FTCs) larger soil organic carbon content and less mineral‐protected carbon, as well as greater post‐thaw increases in dissolved organic carbon, released more CO 2 under FTCs. Such an effect of carbon availability was further confirmed at the global scale. Although FTCs altered the microbial community composition, notably leading to an increase in the proportion of r ‐strategists, microbial properties played a minor role in influencing the CO 2 release. These results demonstrate the crucial role of soil carbon availability in affecting responses of CO 2 release to FTCs, highlighting the need for models to explicitly characterize pulsed CO 2 release associated with substrate availability to better predict permafrost carbon‐climate feedback.

689. 题目: Declines in organic matter persistence with increased soil carbon.
文章编号: N26070903
期刊: Nature Communications
作者: Guang Zhao, Chao Liang, Zhihua Liu, Nan Cong, Zhoutao Zheng, Edith Bai, Juntao Zhu, Bo Zhao, Yixuan Zhu, Mengke Cai, Xiaoqing Duan, Hui Wang, Jianbei Huang, Yangjian Zhang, Susan Trumbore
更新时间: 2026-07-09
摘要: The persistence of soil organic matter (SOM) is critical for predicting carbon-climate feedbacks, yet how increasing soil organic carbon (SOC) relates to long-term SOM persistence across environmental gradients remains unclear. Soil radiocarbon, SOM physicochemical composition, and microbial carbon use efficiency (CUE) are analyzed along a precipitation-driven gradient integrated with global datasets. Here we show, as SOC content increases, its persistence as reflected by radiocarbon signatures declines at both the transect and global scales. This pattern indicates that higher SOC soils are increasingly dominated by younger, faster-cycling carbon rather than older, stabilized pools. Plant carbon inputs strongly predict SOM persistence and are associated with younger, less persistent SOC. While microbial CUE increases with SOC, higher CUE does not necessarily enhance long-term stabilization. Our findings suggest that SOC content alone provides limited insight into long-term soil carbon persistence and highlight the importance of explicitly representing plant carbon inputs and microbially mediated persistence in Earth system models.

690. 题目: Quantification and characterization of soil organic carbon with different environmental gradients for the high altitude wetlands of Indian Himalaya.
文章编号: N26070902
期刊: Environmental Geochemistry and Health
作者: Narayan P Anugraha, D Ganguly, A Paneer Selvam, Kakolee Banerjee, M Harikrishna Prasad, Lakpa Tamang, Sushmita Chettri, Anupriya Soni, Rajesh Joshi, Ajay Kumar Gupta, Prakash Chhetri, Ramachandran Purvaja
更新时间: 2026-07-09
摘要: Himalayan High-altitude wetlands (HAWs) are productive but ecologically fragile ecosystems that store carbon and influence regional biogeochemical cycles. Despite their ecological importance, these wetlands remain poorly studied. This study quantifies and characterizes soil organic carbon (SOC) across three distinct HAWs, two in Sikkim (Tsomgo and Hanspokhri) and one in Ladakh (Tso Moriri), with the aim of identifying the environmental factors governing SOC distribution and quality. Soil samples were analyzed for organic carbon content, physicochemical parameters (moisture, bulk density, texture, and pH), glomalin-related soil protein, and major nutrients to evaluate their collective influence on carbon dynamics. Soil moisture, bulk density, texture, and pH emerged as the main controls on SOC concentration and stability. The maximum carbon stock within the top 30 cm was observed in the ecologically undisturbed Hanspokhri Lake (301 Mg C ha-1), followed by Tsomgo Lake (135 Mg C ha-1) and Tso Moriri Lake (17 Mg C ha-1). Variations in carbon lability among the wetlands reflect the contrasting climatic and geomorphic settings between the eastern and western Himalayas. Furthermore, the strong association between soil nutrients and both labile and non-labile SOC fractions suggests a close coupling between nutrient dynamics and carbon cycling, which is key to wetland soil functioning. These results underscore the significance of high-altitude wetlands as carbon sinks and highlight SOC lability and stability as useful indicators of wetland health, with direct relevance for conservation planning.

691. 题目: 1,3-Dichloro-5,5-dimethylhydantoin (DCDMH)-Driven Sludge Pretreatment for Organic Carbon Valorization: Mechanistic Insights into Controlled Oxidative Disruption and Hormesis-Mediated Metabolic Reshaping.
文章编号: N26070901
期刊: Environmental Science & Technology
作者: Yufen Wang, Xiaofeng Luo, Ya Ji, Tingting Zhu, Yingxin Zhao, Yindong Tong, Bing-Jie Ni, Yiwen Liu
更新时间: 2026-07-09
摘要: Organic carbon valorization via anaerobic sludge fermentation is intrinsically constrained by biopolymer recalcitrance and methanogenic diversion. We introduced 1,3-Dichloro-5,5-dimethylhydantoin (DCDMH) pretreatment leveraging controlled oxidative disruption and microbial metabolic regulation to boost short-chain fatty acid (SCFA) production. At optimal dosage (0.025 g/g TSS), SCFA yield increased by 192.1%, driven by enhanced substrate liberation and biochemical conversion. Molecular docking and 2D-COS FTIR analyses collectively indicate that the N-Cl moiety of DCDMH preferentially oxidized hydrophobic proteins within extracellular polymeric substances, while the derived HClO could penetrate cells to damage intracellular components. This dual action disrupted structural integrity, accelerating macromolecular substrate release and conversion, and enriching stress-tolerant hydrolytic/acidogenic bacteria. Sustained HClO release established oxidative stress wherein reactive oxygen species (ROS) functioned as metabolic signals beyond mere damage indicators. Moderate intracellular ROS stress stimulated substrate acidogenesis while suppressing methanogenic carbon sinks, and enhanced the gene abundances associated with antioxidant defenses and acidogenic pathways. Crucially, this work reveals for the first time the hormetic effect of DCDMH-derived HClO on acidogenic metabolism, providing a new insight into the application of chlorine-containing disinfectants in related fields.

692. 题目: Molecular Drivers of Contrasting Photoreactivity in Extracellular versus Intracellular Organic Matter from Chlorophyta and Cyanobacteria
文章编号: N26070716
期刊: Environmental Science & Technology
作者: Shiqin Mao, Ruijun Lv, Gaoqi Zheng, Ziwen Nie, Fan Luo, Yong Chen
更新时间: 2026-07-07
摘要: Algal organic matter (AOM) is a critical precursor for aquatic photochemical reactions, yet how molecular composition relates to the contrasting photoreactivity of extracellular and intracellular organic matter (EOM/IOM) remains insufficiently understood. This study systematically analyzed the photoreactivity of EOM and IOM derived from representative Chlorophyta and Cyanobacteria. Integrating optical spectroscopy and ultrahigh-resolution mass spectrometry (FT-ICR MS), we characterized the molecular features associated with their photosensitization capacity. EOM, dominated by humic-like substances, functions as a more effective photosensitizer with reactive species (RS) quantum yields up to 22.5-fold higher than protein-like IOM. At the taxonomic level, Chlorophyta-EOM outperformed Cyanobacteria-EOM, whereas Cyanobacteria-IOM exhibited pigment-mediated reactivity. NaBH4 reduction coupled with FT-IR and 2D-COS suggested that EOM photoreactivity was more sensitive to borohydride-sensitive chromophoric moieties, whereas IOM appeared less affected by borohydride treatment. FT-ICR MS revealed EOM contained relatively lignin/CRAM-like and unsaturated molecular features, while irradiated IOM evolved into more saturated and recalcitrant residues, indicative of photochemical aging. These findings provide molecular-level insights into the divergent environmental fates of algal fractions, highlighting EOM as an important contributor to oxidative self-purification, while irradiation of IOM was associated with photochemical aging and the formation of more saturated residual molecular signatures.

693. 题目: Unlocking the Hidden Carbon Pool: Refractory Organic Matter Drives Superior Chain Elongation in Sludge Alkaline Fermentation Liquid
文章编号: N26070715
期刊: Water Research
作者: Dingkang Qian, Ziming Xu, Mengjiao Yuan, Zhen Li, Qian Zhu, Ming Peng, Jianyu Gong, Jiakuan Yang, Jingping Hu, Huijie Hou
更新时间: 2026-07-07
摘要: Converting waste activated sludge (WAS) into medium-chain fatty acids (MCFAs) via chain elongation (CE) offers a promising route for sludge valorization. In two-stage sludge CE systems, primary fermentation is typically optimized to maximize the short-chain fatty acid (SCFA) pool for downstream MCFA production; however, whether retained refractory dissolved and undissolved organic matter (rDOM and rUOM) also contributes to CE remains unclear. Here, we evaluated the roles of rDOM and rUOM in ethanol-driven CE using sludge alkaline fermentation liquid (SAFL) and thermal-alkaline pretreatment fermentation liquid (STAPFL) as feedstocks. Although SAFL contained fewer SCFAs after primary fermentation than STAPFL (3.25 vs. 3.60 g COD/L), it yielded 44% more MCFAs during CE (11.56 vs. 8.03 g COD/L). Integrated physicochemical and molecular analyses indicated that this advantage arose from greater retention of refractory organics during primary alkaline fermentation and their continued mobilization during downstream CE. Filtration experiments and COD-based estimation indicated a much greater total apparent COD contribution from retained rUOM and rDOM in SAFL than in STAPFL (2.16 vs. 0.15 g COD/L). FT-ICR-MS and metagenomic analyses further suggested compositional transformation of retained refractory organics and stronger functional potential for coordinated hydrolysis, acidogenesis, and CE in SAFL, which together supported continued precursor supply and higher MCFA production. These results indicate that downstream MCFA production in real sludge fermentation liquids depends not only on the initial soluble SCFA pool, but also on the continued mobilization of retained refractory carbon during CE. This study advances understanding of retained refractory carbon utilization during ethanol-driven CE in two-stage sludge fermentation for MCFA production.

694. 题目: Elevated hydrostatic pressure promotes organic carbon mineralization in reservoir sediments
文章编号: N26070714
期刊: Water Research
作者: Yan Zhang, Shangbin Xiao, Defu Liu, Wenjun Yang, Huiqun Cao, Jia Liu, Chenghao Wang, Li Zhu, Shijian Li, Shiping Lai, Xinghui Xia
更新时间: 2026-07-07
摘要: Sediment organic carbon mineralization is a key biogeochemical process regulating the balance between organic carbon decomposition and preservation in aquatic systems. Reservoir impoundment substantially alters the hydrostatic pressure regime experienced by sediments, yet its impacts on sediment organic carbon mineralization remain poorly understood. Here, using a custom-built hydrostatic pressure simulation system, we show that increasing hydrostatic pressure (0.1-2.1 MPa) significantly accelerates sediment organic carbon mineralization. In non-sterilized sediment-water incubations, the apparent organic carbon mineralization rate (CMR) at 2.1 MPa was 1.45-, 2.01-, and 1.72-fold higher than at 0.1 MPa on day 3, 6, and 9, respectively. In water-only incubations, the stimulatory effect was even stronger initially, with the CMR at 2.1 MPa reaching 4.59-fold higher than at 0.1 MPa on day 10, but declined rapidly over time. In sterilized sediment-water incubations, overlying-water DOC at 2.1 MPa was 1.26-fold higher than at 0.1 MPa, indicating that hydrostatic pressure can enhance DOC release even when microbial activity is suppressed. These findings reveal hydrostatic pressure as an overlooked control on sediment organic carbon mineralization and suggest that pressure-driven carbon transformation may be relevant to assessments of organic carbon burial efficiency and greenhouse-gas production potential in deep reservoirs.

695. 题目: Differential degradation pathways of organic matter driven by coastal fronts: Implications for carbon burial efficiency in the Beibu Gulf.
文章编号: N26070713
期刊: Journal of Environmental Management
作者: Qibin Lao, Chunqing Chen, Guangzhe Jin, Xuan Lu, Chao Wang, Fajin Chen
更新时间: 2026-07-07
摘要: Coastal fronts create critical transition zones where intensified physical-biological coupling regulates aquatic biogeochemical cycles and ecosystem services. However, mechanistic insights of organic matter (OM) dynamics in response to frontal processes, along with their associated carbon sequestration and potential eco-environmental effects, remain poorly constrained due to a paucity of field observations. This study conducted a systematic investigation of dissolved OM (DOM) characteristics across seasonal cruises, integrating satellite remote sensing data, particulate OM (POM) and physicochemical parameters profiling to elucidate frontal controls on OM dynamics. Our findings demonstrated front-dependent modulation of OM processing pathways. In the high-intensity northern frontal zone, enhanced vertical mixing supplied abundant nutrients, stimulating phytoplankton growth. The dominant OM processing pathway therefore involves the phytoplankton production and subsequent degradation of fresh POM, releasing abundant labile DOM into the water column. By contrast, in the low-intensity eastern frontal zone, despite substantial DOM input via the West-Guangdong Coastal Current (with >40% of the annual input occurring in winter), weak frontal intensity failed to supply adequate nutrients to sustain autochthonous production, shifting the system toward direct microbial degradation of DOM as the primary removal process. These findings demonstrate that frontal activity serves as a hotspot for the dynamic processing of both POM and DOM in the water column, providing insights into how frontal dynamics influence coastal carbon cycling and highlighting the potential vulnerability of carbon sinks under future climate change.

696. 题目: Cadmium pollution alters the priming effect of biochar application on soil organic carbon mineralization.
文章编号: N26070712
期刊: Journal of Environmental Management
作者: Meng Na, Mengqin Xiang, Yunfeng Wu, Dengzhi Wu, Shangqi Xu, Lei Wang, Jihai Zhou, Johannes Rousk
更新时间: 2026-07-07
摘要: Biochar has high potential to reduce cadmium (Cd) bioavailability in polluted soils. While effective in Cd remediation, biochar amendment can stimulate native soil organic carbon (SOC) mineralization via the priming effect, resulting in soil C release. However, it remains unclear whether Cd pollution alters the impact of biochar application on SOC mineralization, and how microbes modulate biochar-induced priming effect in Cd-polluted soils. To address these questions, a 120-day laboratory experiment was conducted by applying two types of biochar derived from C4 crop residues to C3 paddy soils under Cd pollution (0, 4 and 8 mg kg-1). In unpolluted soils, sorghum biochar, with higher C availability and C:nitrogen (N) ratios, triggered stronger positive priming of SOC mineralization than sugarcane biochar. This process was mediated by bacterial groups, where higher N-degrading gene abundances and associated enzyme activities promoted N-mining from soil organic matter (SOM). Low Cd pollution reduced priming responses, resulting in an overall negative priming. This result coincided with increased DOC and mineral N, which mitigated microbial resource demand from SOM. Under high Cd, sorghum biochar induced a positive cumulative priming at the late stage, whereas sugarcane biochar triggered an overall negative priming. This could be because higher labile C in sorghum biochar sufficiently activated microbes to produce enzymes which co-metabolized SOM, a process driven by fungal groups and persistent C-degrading genes. These findings highlight a double-edged sword effect that biochar remediation of highly Cd-polluted soils has the potential to trigger soil C emissions.

697. 题目: Low carbon lightweight panels reinforced with biochar and simulated for passive thermal regulation in smart buildings.
文章编号: N26070711
期刊: Environmental Science and Pollution Research
作者: Mahapara Abbass, Sana Abass Wani, Arti Chouksey, Shalom Akhai
更新时间: 2026-07-07
摘要: The rising demand for carbon-neutral construction materials has driven research into alternatives to conventional cement-based panels. This study develops lightweight, low-carbon geopolymer panels reinforced with biochar derived from agricultural residue. By partially substituting sand with biochar, the panels exhibit enhanced thermal insulation while maintaining adequate mechanical and durability properties. Experimental investigations confirmed improvements in thermal conductivity, chloride resistance, and acid durability up to an optimum biochar content of 10-15%. Additionally, dual-domain numerical simulations demonstrated the panels' dimensional stability under transient heat transfer and thermal stress conditions, indicating their ability to passively regulate indoor temperature. The findings establish biochar-geopolymer composites as a scalable, sustainable pathway for smart building envelopes, aligning with circular economy principles and climate-resilient construction practices.

698. 题目: Sensitivity of ultrafine particle and black carbon simulations to model resolution and emission data in urban environment with a focus on Barcelona
文章编号: N26070710
期刊: Environmental Pollution
作者: Pablo Olivares Lopez, Lya Lugon, Oriol Jorba, Karine Sartelet
更新时间: 2026-07-07
摘要: Under the new Ambient Air Quality Directive, monitoring of ultrafine particles as particle number (PN) and black carbon (BC) is required due to their health impacts, making their improved representation in air quality models particularly relevant. This study investigates the influence of spatial resolution and anthropogenic emission inventories on the simulation of PN, BC, and regulated pollutants (NO2, O3, PM10, PM2.5) at urban background sites in Europe, with particular focus on Barcelona (Spain). Simulations were performed with the WRF/CHIMERE/SSH-aerosol system over three nested domains at 15, 5, and 1 km horizontal resolution. Over Spain, at 5 and 1 km resolutions, the European-scale EMEP inventory (10 km spatial resolution) and the Spanish high-resolution bottom-up emission inventory HERMESv3 BU (1 km spatial resolution) were evaluated. The choice of emission inventory exerts a control on model performance, particularly for NO2, BC and PN. At 5 km resolution, HERMESv3 reduces the systematic underestimation of pollutant concentrations compared to EMEP. While increasing resolution from 15 km to 5 km improves urban gradients, further refinement to 1 km does not substantially improve statistical performance at the urban background station of Barcelona; however, it enhances the representation of spatial heterogeneities and sharpens intra-urban gradients, especially for NO2, BC, and PN. The modelling framework and methodology implemented enable the simulation of emerging pollutants, such as BC and PN, with a statistical performance comparable to that achieved for regulated pollutants.

699. 题目: Ecological division of labor between abundant and rare taxa drives soil Cd remediation via Bacillus licheniformis-loaded biochar
文章编号: N26070709
期刊: Journal of Hazardous Materials
作者: Zheng Lin, Runtong Huang, Shunan Zhang, Xiantao Fang, Weimin Sun, Lei Wang, Rui Du, Shuai Xiao, Yun Zhang, Zhimin Xu
更新时间: 2026-07-07
摘要: Cadmium (Cd) contamination in agricultural soils threatens food security and calls for sustainable remediation. Biochar-microbe composites are a promising option, yet the respective ecological roles of abundant and rare microbial taxa in Cd immobilization and plant uptake remain poorly resolved. Here, a bacteria-loaded biochar (BLB) was prepared from FeCl₃-modified kitchen-waste biochar and Bacillus licheniformis. Spectroscopic and microscopic analyses indicated that bacterial colonization introduced biogenic nitrogenous groups (C-N, N-H) and promoted the formation of surface iron oxyhydroxides, which together favored stable inner-sphere complexation (e.g., Fe/Mn-O-Cd and COO-Cd). In pot experiments, BLB reduced exchangeable Cd by 51.7% and shoot Cd concentration by more than 70% relative to the control, while improving the growth of lettuce (Lactuca sativa). These outcomes were accompanied by distinct, taxon-associated patterns in the rhizosphere and root microbiomes. Abundant taxa were primarily associated with nutrient supply and plant biomass, consistent with a growth-dilution effect on tissue Cd. Rare taxa were correlated with the transformation of Cd into more stable fractions and with co-occurrence network stability, in line with a putative role as biochemical specialists. BLB application coincided with a shift toward deterministic assembly of root endophytes, in which enrichment of Pseudomonadaceae was linked to reinforced Casparian strips and reduced Cd translocation. Structural equation modeling confirmed a tripartite synergistic mechanism comprising rhizosphere detoxification, microbial niche differentiation, and internal plant interception. These findings highlight that manipulating the abundant-rare microbial guilds via functionalized biochar is a potent strategy for achieving both soil remediation and safe crop production.

700. 题目: Insights into the effects of Fe3O4-modified biochar on anaerobic co-digestion of food waste and corn stover: Roles of electron transfer regulation and microbial community shaping
文章编号: N26070708
期刊: Journal of Environmental Chemical Engineering
作者: Yinping Hou, Ziyi Yang, Fangyuan Wang, Wangtao Dong, Yu Chen, Hongrui Ma, Chengtao Li, Peng Zhang
更新时间: 2026-07-07
摘要: Anaerobic digestion (AD) of food waste (FW) is frequently hindered by volatile fatty acid (VFA) accumulation, inefficient electron transfer, and poor stability, severely limiting methane recovery. This study targeted these bottlenecks by optimizing the carbon-to-nitrogen (C/N) ratio via co-digestion (co-AD) with corn stover (CS), and further strengthened syntrophic metabolism using Fe3O4-modified biochar (Fe3O4-BC). At the optimal FW/CS ratio of 6:4 (C/N = 25.94), the synergistic index reached 1.17 ± 0.02, with a maximum methane yield of 411.58 ± 7.26 mL/g VS. Among the composites prepared at 300 ℃, 500 ℃ and 700 ℃, Fe3O4-BC500 exhibited the most significant promoting effect on co-AD. The cumulative methane production increased by 32.65% while the lag time (λ) was shortened by 49.76%. This was attributed to its abundant quinone redox-active groups, which efficiently facilitated interspecies electron transfer, accelerated VFA metabolism, and thereby improved the system stability. It Electrochemical assays confirmed its higher electron exchange capacity (1.23 mF/g) and electron transport system activity (1.01 ×10−2 μg/(mg·h)). Fe3O4-BC500 effectively stimulated microbial activity and enhanced the functional capacity of methanogens. Dehydrogenase (DHA) activity and Coenzyme F420 levels increased by 24.79% and 48.10%, respectively. It facilitated the enrichment of electroactive bacteria (Syntrophobacter, Syntrophomonas) and acetoclastic methanogen Methanosaeta, thus promoting direct interspecies electron transfer and steering methanogenesis toward a more efficient pathway. This work provides a mechanistic and practical strategy for designing redox-active biochar to boost electron transfer efficiency and stabilize co-AD of organic wastes.