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161. 题目: Redox‐Active Organic Matter in a Boreal Peatland Demonstrates Resistance to Global Climate Change
文章编号: N26032701
期刊: Global Change Biology
作者: Jessica E Rush, Jason K Keller, Cassandra A Zalman, Zachary S Schwartz, Eve‐Lyn S Hinckley
更新时间: 2026-03-27
摘要: Redox‐active organic matter (RAOM) reduction is an important control on carbon cycling in boreal peatlands, suppressing methane production via its energetic favorability. However, the effects of global climate change drivers—notably, warming and elevated atmospheric carbon dioxide (CO 2 )—on the relationship between RAOM and production of greenhouse gases remains unknown, constituting an important knowledge gap. Here, we leveraged an experimental boreal peatland in northern Minnesota (USA) that has been subjected to a gradient of warming (+0 to +9°C) and elevated CO 2 (+500 ppm) for almost 10 years. To understand in situ effects of field treatments on RAOM, we equilibrated a homogenized peat substrate and peat from the bog along the depth profile for 1 month in the field. Elevated CO 2 did not have a significant effect on RAOM reduction ( p > 0.05) in either peat type. Increased experimental temperatures stimulated RAOM reduction in the homogenized peat substrate ( p < 0.05), but there were no effects of warming on RAOM reduction in peat from the bog ( p > 0.05). To better understand indirect effects of the treatments, we also measured the potential for RAOM reduction in peat from each treatment under standardized laboratory conditions. The amount of reduced RAOM was variable at 10–20 cm (~15–70 μmoles e − /g dw peat) and there were no clear patterns of warming or elevated CO 2 effects on RAOM reduction. We compared these findings to measurements conducted in 2016 and found similar microbial processing of the RAOM pool among treatments and a slight decrease in potential RAOM pools over time at three depths (10–20 cm p = 0.60; 75–100 cm and 175–200 cm p < 0.05). Collectively, our findings suggest an unexpected conclusion: peatland RAOM reduction may be resistant to warming and elevated atmospheric CO 2 .

162. 题目: Source-specific carbon dioxide production and acetoclastic methanogenesis upon anaerobic degradation of dissolved organic matter
文章编号: N26032615
期刊: Geochimica et Cosmochimica Acta
作者: Yongqiang Zhou, Jiayi Wu, Lei Zhou, Yunlin Zhang, Kyoung-Soon Jang, Liwei Zhang, José R Paranaíba, Christopher C Keneally, Justin D Brookes, David P Hamilton, Erik Jeppesen
更新时间: 2026-03-26
摘要: Lakes receive and process diverse sources of dissolved organic matter (DOM), which contribute differently to the production of carbon dioxide (CO2) and methane (CH4) within the system. Here, we isolated DOM from soil, algae, submerged macrophytes, and sewage, then tracked their anaerobic fate for 56 days with high-frequency isotope and ultrahigh-resolution mass spectrometry analyses. Biolabile macrophyte-, sewage-, and algal-DOM lost approximately 80% of DOC within 56 days, leading to CO2 concentrations of up to 1422 µmol L−1 and CH4 concentrations of up to 1.59 µmol L−1 for the macrophyte-DOM group. These concentrations were 6 to 9-fold higher than those found for soil-DOM and 30 to 90-fold higher than their initial levels. The calculated carbon isotope fractionation factor (αC) decreased from initial values of 1.05–1.10 to 1.03–1.04 by day 56, and δ13C-CH4 rose to −40‰, indicating the immediate dominance of the acetoclastic methanogenic pathway. Extreme gradient boosting models identified δ13C-DOC as a key predictor of both CO2 and CH4 concentrations. Degradation of 1 mg algal DOC yielded 47 µmol CO2 and 0.04 µmol CH4, surpassing soil-derived yields by 7- and 4-fold, respectively. By quantifying yield coefficients and identifying δ13C-DOC as a key predictor, we move beyond qualitative patterns; the immediate onset of acetoclastic methanogenesis across all sources provides a mechanistic framework for modeling emissions from mixed DOM pools in natural systems

163. 题目: Roles of dissolved organic matter, Cl−, and NO3− in the photodegradation of β-estradiol in seawater
文章编号: N26032614
期刊: Marine Pollution Bulletin
作者: Diyi Liu, Lu Liu, Ping Yin, Yan Tian, Jing Zhang
更新时间: 2026-03-26
摘要: 17β-Estradiol (E2), a typical endocrine-disrupting chemical, is widely detected in various aquatic environments, including rivers, lakes, groundwater, estuaries, and coastal waters, posing significant ecological and health risks. Photodegradation is a key pathway for the transformation and removal of E2 from aquatic systems. This study investigated the effects of dissolved organic matter (DOM) from different sources and common inorganic anions (Cl− and NO3−) on E2 photodegradation under simulated solar irradiation. The results indicated that the excited triplet state of DOM (3DOM*), generated upon light absorption, was the key reactive species driving E2 photodegradation. Among the DOM sources examined, humic acid exhibited the strongest promotive effect on E2 photodegradation. Correlation analysis confirmed that terrestrial humic-like components within seawater DOM were the primary contributors to 3DOM* formation. Seawater DOM from nearshore areas exhibited higher steady-state concentrations of 3DOM* owing to greater terrestrial input. Both Cl− and NO3− effectively accelerated E2 photodegradation, and the E2 degradation rate increased with their concentrations. In contrast, the coexistence of Cl−, NO3−, and DOM inhibited E2 photodegradation. In DOM-dominated systems, the main transformation pathways of E2 involved oxidation and hydrolysis reactions on the phenolic ring. This study elucidates the effects of DOM source and water chemical composition on E2 photodegradation, which is crucial for accurately predicting its environmental fate and ecological risks. Moreover, the findings provide valuable insights into the photochemical transformation of other emerging organic contaminants.

164. 题目: Constructing a Z-scheme heterojunction on leather waste-derived biochar supporting graphitic carbon nitride for highly-efficient photocatalysis toward water decontamination
文章编号: N26032613
期刊: Chemical Engineering Journal
作者: Liming Zhao, Rui Dai, Yuling Tang, Xin Cheng, Jianfei Zhou, Bi Shi
更新时间: 2026-03-26
摘要: Simultaneous management of hazardous solid waste and remediation of organic-contaminated water presents critical environmental challenges. While photocatalysis offers a sustainable solution, developing robust, cost-effective catalysts through waste upcycling remains underexplored. This work demonstrates the successful fabrication of a novel all-solid-state heterojunction photocatalyst, g-C3N4/BC/Cr2O3, via a facile in-situ pyrolysis strategy utilizing hazardous leather waste, i.e., chrome shavings, as a dual-source precursor. This unique approach simultaneously achieved the carbonization of collagen fibers into conductive biochar (BC) and the transformation of intrinsic toxic Cr(III) into photoactive Cr2O3 nanoparticles, which were intimately anchored with graphitic carbon nitride (g-C3N4). The synthesized composite exhibits a significantly narrowed bandgap of 2.48 eV and extended visible-light responsiveness up to 624 nm, attributable to the synergistic coupling effects among the constituents. A robust direct Z-scheme charge transfer pathway is established, mediated by BC interlayer acting as a highly conductive solid-state electron shuttle. This architecture effectively suppresses the recombination of photogenerated carriers, thereby endowing the composite with exceptional photocatalytic activity toward methylene blue (MB) degradation, achieving a rate 4.1 times higher than that of pristine g-C3N4. Mechanistic investigations identify superoxide radicals ( ) as the primary reactive species, synergistically assisted by holes (h+) and hydroxyl radicals (•OH). g-C3N4/BC/Cr2O3 further demonstrates remarkable cyclic stability, negligible metal leaching, and versatile efficacy against a broad spectrum of refractory organic dyes. This study not only reports a high-performance and eco-friendly photocatalyst but also pioneers a “waste-to-wealth” paradigm for upcycling industrial wastes into advanced functional materials for water purification.

165. 题目: Synergistic effect of β-cyclodextrin-functionalized biochar -based bacterial agent on soil lead/cadmium passivation and plant growth promotion
文章编号: N26032612
期刊: Chemical Engineering Journal
作者: Jianbang Zhu, Qiwen An, Mengning Wang, Irina B Ivshina, Xu Sun, Jiaqi Liu, Bohao Jing, Yongtao Zhou, Siyue Han, Jianhua Qu, Ying Zhang
更新时间: 2026-03-26
摘要: This study engineered a novel bacterial agent based on phosphate-solubilizing bacteria immobilized on β-cyclodextrin-functionalized and phosphorus-doped biochar (β-PBC@PSB), for synergistic remediation of soil contaminated with lead (Pb) and cadmium (Cd). Batch adsorption experiments revealed exceptional Pb(II)/Cd(II) adsorption capacities (396.81/187.01 mg/g) via integrated precipitation, electrostatic attraction, and biomineralization. Soil experiments demonstrated that 1% β-PBC@PSB reduced bioavailable Pb/Cd (DTPA-Pb/Cd was 90.5/0.83 mg/kg) while converting their labile fractions to residual species (residual Pb increased by 10.37% and residual Cd increased by 11.02%). Pot experiments confirmed significant cucumber growth promotion (fresh weight increased by 173%) with reduced metal accumulation (74% decrease in root Pb and 59.7% decrease in root Cd), attributed to enhanced photosynthesis and suppressed oxidative stress. The amendment concurrently improved soil functionality: available phosphorus rose by 47%, acid phosphatase activity intensified, and microbial restructuring enriched beneficial genera. β-PBC@PSB still possessed excellent immobilization performance after 20 wet-dry/freeze-thaw cycles, with DTPA-extractable Pb/Cd only slightly increasing to 99.6/0.95 mg/kg (wet-dry cycles) and 95.6/0.94 mg/kg (freeze-thaw cycles), demonstrating long-term stability. This multifunctional material provides an effective strategy for passivating heavy metals, restoring soil health, and ensuring crop safety in farmland ecosystems.

166. 题目: Dual role of lignin related compounds: forming chromophoric dissolved organic matter (CDOM)−like spectra and quenching CDOM’s fluorescence spectra
文章编号: N26032611
期刊: Water Research
作者: Chi Zhou, Zhuo Wang, Hanmei Zhao, Xu Zhang
更新时间: 2026-03-26
摘要: Elucidating the molecular structure of chromophoric dissolved organic matter (CDOM) remains a central challenge in its research. Investigating the spectral changes of lignin derivatives during their transformation provides insights into the molecular basis that dictate CDOM’s optical behavior. Photolysis of lignin-related compounds (LRCs), such as coniferyl aldehyde (Coni) and sinapaldehyde (Sina), yields products with spectral signatures closely resembling those of CDOM. The specific UV absorbance at 254 nm (SUVA254), spectral slope (S₃₀₀–₇₀₀), and E2:E4 ratio (A250/A365) of the irradiated Coni and Sina were 3.98 and 3.20 L·mgC-1 m-1, 0.0153 and 0.0176 nm⁻¹, and 4.38 and 7.02, respectively. All these values closely match those of Suwannee River natural organic matter (3.25 L·mgC-1 m-1; 0.0152 nm-1; 4.58). The fluorescence quantum yields at excitation wavelengths of 375 nm (1.5-3.0 × 10-3) and 440 nm (1.3-2.9 × 10-3) were comparable to those of CDOM isolates. On the other hand, Coni and Sina quenched the fluorescence of CDOM possibly through both static and dynamic processes. Terrestrial CDOM was more readily quenched than aquatic CDOM, and the quenching efficiency was higher for untreated CDOM than for sodium borohydride-reduced CDOM. LRCs preferentially quenched fluorophores with a relatively long lifetime and caused a hypsochromic shift in the CDOM spectra. The fluorescence quenching efficiency for CDOM in water/organic solvent (isopropanol and tetrahydrofuran) mixed solutions gradually decreased with an increasing volume ratio of the organic solvent, indicating that the conformation of CDOM or the accessibility of fluorophores changes with solvent polarity.

167. 题目: Organic fertilizers reduce N2O and NH3 emissions by regulation soil nitrogen pool and microbiome
文章编号: N26032610
期刊: Journal of Environmental Management
作者: Xinyao Fan, Yi Wang, Wenqi Liang, Xu Ma, Wenming Zhang, Chenxu Yu
更新时间: 2026-03-26
摘要: Organic fertilizers are generally considered beneficial towards maintaining long term soil health, yet they could elevate N2O and NH3 emissions which raise concerns regarding air pollution and climate change. In this study, four types of organic fertilizers (raw sheep manure, RSM; composted sheep-manure organic fertilizer, OF; biochar-amended organic fertilizer, CharOF; sterilized OF, SOF) were applied onto three kinds of soils in microcosm cultivation to explore their effects on N2O and NH3 emissions and the underlining mechanisms. The results showed that traditional organic fertilizers (RSM and OF) significantly increased N2O and NH3 emissions from the soils, whereas CharOF reduced by as much as 23.0% in N2O and 18.4% in NH3 from that of RSM/OF peaks. Both OF and SOF significantly increased soil total nitrogen (TN) and organic nitrogen (Org-N), while CharOF significantly improved soil NO3--N, NH4+-N and microbial biomass nitrogen (MBN). Metagenomic sequencing showed that RSM and OF significantly increased denitrification genes norB and narI, dissimilatory nitrate reduction genes nasA, napA and nirB, and mineralization gene ureC, while CharOF slightly suppressed denitrification genes nirS and narI, dissimilatory nitrate reduction genes nasA/B, napA, nirB and NR, and mineralization gene ureC. RDA analysis revealed that NO3--N, NH4+-N, MBN and pH were the environmental factors affecting NC relevant genes and gas emissions. PLS-PM model revealed that soil nitrogen pool correlated stronger to the NH3 and N2O emissions than that of nitrogen cycle (NC) relevant genes. This study provides a theoretical foundation for the promotion of low-pollution fertilization practices in green agriculture, and contributes to the advancement of agricultural sustainability. Additionally, it offers fresh perspectives on organic fertilizer production and its role in enhancing socio-economic systems for public benefits.

168. 题目: Dissolved nitrogen and phosphorus trigger Euglena sanguinea blooms via Burkholderiaceae enrichment and extracellular polymeric substance stimulation
文章编号: N26032609
期刊: Journal of Environmental Management
作者: Fang Yu, Huiyun Feng, Zengliang Yu, Jingang Jiang, Shaoqiu Li, Jingjing Meng
更新时间: 2026-03-26
摘要: As representative landscape water bodies, urban park ponds are typically shallow and hydrologically isolated, making them highly susceptible to algal blooms. This study focused on recurrent summer-autumn blooms of Euglena sanguinea in Hefei Binhu Forest Park. These blooms form thin, red, oil-slick-like surface scums that severely suppress aquatic photosynthesis. We investigated phytoplankton community succession and its drivers by collecting surface biofilm, mid-depth water, and bottom sediment samples from three representative ponds during the 2024 bloom season. Results revealed extensive E. sanguinea blooms in July-August, with surface cell density reaching 9.86 × 106 cells/L (42% of total) and biomass attaining 98.61 mg/L (94% of total). This bloom peak coincided with a 2.5-fold increase in surface dissolved total nitrogen (DTN) and phosphorus (DTP). Concurrently, the surface biofilm exhibited a peak extracellular polymeric substance (EPS) concentration of 43.92 mg/L and a film-forming rate of 90.73%, structurally supported by the predominance of large algal-bacterial aggregates (>64 μm), which accounted for nearly 80% of the particulate composition. The bounding EPS (BEPS), rich in tryptophan-like proteins, corresponded with peak biofilm hydrophobicity. Critically, this nutrient-enriched microenvironmental transformation selected for a low-diversity, high-dominance microbiome. Burkholderiaceae dominated the August biofilm (23%), contrasting sharply with sediment communities (dominated by Steroidobacteraceae, 7%) and post-bloom October biofilms (dominated by Sporichthyaceae, 21%). Mechanistic path analysis revealed that DTN and DTP stimulated bloom expansion not by directly promoting algae, but by enriching Burkholderiaceae and stimulating EPS production. These findings elucidate a microbially mediated pathway linking nutrient enrichment to E. sanguinea bloom formation, challenging the conventional direct nutrient-bloom paradigm. The study provides mechanistic blueprint for targeted, microbiome-informed management of urban landscape water blooms.

169. 题目: Changes of intracellular and extracellular organic matter in Microcystis colonies after ultrasonic stress and during recovery cultivation
文章编号: N26032608
期刊: Journal of Environmental Management
作者: Jia Liang, Zhipeng Duan, Lei Liu, Chao Xing, Xiao Tan, Jun Sun, Yangxue Xu, Rui Zhu
更新时间: 2026-03-26
摘要: Cyanobacterial harmful algal blooms (CyanoHABs) impair aquatic ecosystem and restrict water utilization. Ultrasound is an effective method for controlling Microcystis blooms. However, this treatment may trigger the release of extracellular and intracellular organic matter to the environment, potentially causing secondary pollution. In this study, Microcystis colonies were treated with an ultrasonic generator (35 kHz, 0.035 W cm-3) for 0-600 s to assess their immediate responses, including changes in colony morphology, EPS, and DOM release. Additionally, the treated cyanobacteria were cultivated at different temperatures to determine the variation patterns of EPS and released DOM during recovery growth. The results indicated that ultrasound-induced cavitation and reactive oxygen species might decrease the easily degradable tyrosine-like substances in EPS, weakening cell adhesion and collapsing large colonies into small ones (<50 μm, p < 0.05). Ultrasound over 60 s promoted DOM release, from which amino acid-like substances could potentially provide nitrogen for protein synthesis in damaged cyanobacterial cells. While the 30s-treated algae improved their stress resistance by enhancing the production of humic-like substances under nitrogen deficiency. Higher temperatures (>25 °C) might promote the metabolism and viability of ultrasonically treated Microcystis, increasing EPS and chromophoric DOM (CDOM) secretion. This study emphasized the necessity of optimizing ultrasonic parameters and monitoring the accelerated recovery of treated Microcystis blooms, especially under high temperatures. The findings of this study will facilitate the practical application of ultrasound-based CyanoHABs control techniques and the management of aquatic environmental quality.

170. 题目: Proxy-based high-resolution inventory of black carbon emissions in Taiwan: Insights into spatiotemporal variations in urban cities and non-urban areas
文章编号: N26032607
期刊: Journal of Environmental Management
作者: Sultan F I Abdillah, Sheng-Jie You, Ya-Fen Wang
更新时间: 2026-03-26
摘要: Black carbon (BC) is a major short-lived climate pollutant (SLCP) that contributes substantially to global warming and adverse health outcomes, particularly in densely populated regions. Although several regional black carbon emission inventories exist, their coarse spatial resolution limits the ability to assess urban-level disparities and to support city-level mitigation planning. To address this gap, this study develops the first long-term, proxy-based, high-resolution BC emission inventory for Taiwan, covering the period 2000-2024. Chung Yuan Christian University-BC (CYCU-BC) inventory database was developed with a 1 km × 1 km and annual resolutions. CYCU-BC estimation results indicated a pronounced long-term decline in national BC emissions decreasing from approximately 17,124 t/y (95%CI: 8,924 - 25,377 t/y) in the early 2000s to about 4,290 t/y in the early 2020s, driven primarily by transportation (82.6%), agriculture (9.6%), and residential sectors (2.5%). Inter-comparisons and Monte Carlo analysis indicated good agreement with established regional inventories with differences ranging from -38.6% to +9.9% and uncertainty of 23% - 25%. More than 70% of total BC emissions were consistently concentrated within urban agglomeration city clusters, while non-urban areas exhibited substantially lower emissions with distinct sectoral contributions and emission dynamics. By resolving black carbon emissions at the city scale over multiple decades, this study provides a robust scientific basis for targeted mitigation strategies. It also supports integrated climate-health policy design in rapidly urbanizing regions. Together, these findings highlight the critical role of high-resolution emission inventories in mitigating SLCPs.

171. 题目: Geostaionary satellite observations reveal diurnal dynamics of particulate organic carbon in optically complex lakes
文章编号: N26032606
期刊: Journal of Hydrology
作者: Kun Xue, Ronghua Ma, Minqi Hu, Menghua Wang, Yang Cheng, Lide Jiang, Zehui Huang
更新时间: 2026-03-26
摘要: Diurnal dynamics of particulate organic carbon (POC) play a critical role in lake carbon cycling but remain poorly quantified at regional scales. Using hourly observations from the Geostationary Ocean Color Imager (GOCI) (08:16–15:16, UTC + 8; 500 m spatial resolution), we examined POC variability across 52 lakes in the middle and lower reaches of the Yangtze and Huai River (MLYHR) basin in China (2011–2021). Four diurnal POC metrics, including the daily mean values of POC (POCmean), the coefficient of variation of POC (POCcv), relative difference between afternoon and morning POC (dPOC), and centroid of hourly POC (cPOC), showed substantial spatial and temporal variability. Both POCmean and POCcv peaked in summer and autumn, with maximum values in September (5.60 mg/L), and declined during winter and spring. Negative dPOC values (–6.48 ± 15.39%) were found in 73.96% of pixels, indicating afternoon-dominated POC conditions, and cPOC was tightly clustered at 11.49 ± 0.17 h (UTC + 8). The Fuzzy C-Means clustering method identified three distinct diurnal POC patterns: Type 1 (decreasing), Type 2 (increasing), and Type 3 (midday peak). Interannual analyses suggested post-2014 trend shifts in diurnal POC metrics, with metric-dependent uncertainty. Driver analysis revealed that temperature and solar radiation primarily control diurnal POC dynamics, while wind influences POCcv by modulating the vertical movement and mixing of POC. Structural equation modeling highlighted distinct mechanisms underlying each diurnal pattern, particularly for dPOC and cPOC. These findings can provide a basis for optimizing lake carbon flux models by incorporating daytime diurnal POC dynamics, and highlight the necessity of incorporating diurnal-scale processes into environmental monitoring and policy frameworks.

172. 题目: Functional differentiation of DOM is coupled with nitrogen cycling in large reservoirs along an altitudinal gradient: Antagonism between condensed aromatics and carbohydrates is associated with retention and removal
文章编号: N26032605
期刊: Journal of Hydrology
作者: Chen Li, Wei Wu, Hang Chen, Lei Ren, Sheng Xu, Zeyu Xiao, Na Zhang, Yuxuan Shi
更新时间: 2026-03-26
摘要: Understanding how the chemodiversity of dissolved organic matter (DOM) regulates nitrogen biogeochemical cycling in plateau reservoirs is critical for developing adaptive nitrogen management strategies under dual natural and anthropogenic stresses. This study investigates the potential DOM molecular mechanisms mediating nitrogen cycling across large reservoirs situated at high-(2400–2800 m), mid-(2000–2400 m), and low-elevation (1600–2000 m) zones in the upper Yellow River, northeastern Tibetan Plateau. By integrating spectroscopy, FT-ICR MS, and dual-isotope tracing, we observed a sharp elevational shift in nitrogen sources, transitioning from soil-dominated inputs (45.4%) at high elevations to manure and sewage dominance (44.4%) at low elevations. While nitrification remained the primary turnover pathway, its controlling factors shifted from evaporation-driven natural processes at high elevations to agricultural and anthropogenic inputs at lower altitudes. Specifically, we demonstrate that the antagonistic interplay between condensed aromatics and carbohydrates potentially influences the balance between nitrogen retention and removal. As DOM composition shifts from allochthonous/recalcitrant to autochthonous/labile with decreasing altitude, three distinct functional regimes emerge: (1) a high-elevation “Nitrogen Locking Effect,” where soil-derived condensed aromatics inhibit denitrification, causing nitrate accumulation; (2) a mid-elevation zone maintaining a “Dynamic Balance” between nitrogen accumulation and loss; and (3) a low-elevation “Nitrogen Pumping Effect,” where sewage-derived carbohydrates fuel assimilation and denitrification to drive rapid nitrogen depletion. These findings highlight the role of DOM molecular components in regulating nitrogen cycles and provide a mechanistic framework for deciphering nitrogen fate in fragile plateau ecosystems.

173. 题目: Temporal dynamics of microbial residues and their role in soil organic carbon sequestration across a chronosequence of Chinese fir plantations in subtropical China
文章编号: N26032604
期刊: Catena
作者: Junjie Lei, Feifei Xie, Yuanying Peng, Xiaocui Liang, Peng Dang, Xiaoyong Chen, Wende Yan
更新时间: 2026-03-26
摘要: Microbial residue carbon (MRC) is crucial for soil organic carbon (SOC) sequestration, yet its temporal dynamics during plantation development and successive rotation remain unclear. This study investigated SOC fractions, microbial living biomass, and microbial residues to estimate the contribution of MRC to SOC in 8-, 16-, 24-, and 34-year-old second-generation Chinese fir plantations, with a 106-year-old original plantation serving as the control. The results revealed that SOC content increased with stand age, exceeding the control level at the 34-year-old stand. Soil microbial living biomass and MRC content exhibited a decline-then-increase trend with stand age, remaining below the control. The contribution of MRC to SOC decreased with stand age and was significantly higher in the 8-year-old stand than in the control, averaging 30.7% of the SOC. Although SOC fractions and microbial parameters were higher in the topsoil, the contribution of MRC to SOC was greater in the subsoil. Notably, soil fungi accounted for 14.3% of the microbial living biomass, yet their residues accounted for 84.9% of the MRC. The positive association between mineral-associated organic carbon and fungal residues was markedly stronger than that for bacterial residues. Random forest and mixed-effect analyses indicated that MRC accumulation was primarily regulated by microbial living biomass and soil carbon and nitrogen, rather than by plant growth metrics. Path analysis further confirmed the strongest direct influence of soil microbial living biomass on MRC accumulation. Our findings elucidate the dynamics of MRC accumulation and its role in long-term SOC sequestration during plantation development in subtropical China.

174. 题目: Soybean integration increases pore connectivity and particulate organic matter while reducing shrinkage in saline Fluvo-aquic soil: An X-ray CT study
文章编号: N26032603
期刊: Soil and Tillage Research
作者: Tianyu Ding, Zichun Guo, Yueming Chen, Shenzhong Tian, Jianli Liu, Xinhua Peng
更新时间: 2026-03-26
摘要: Saline Fluvo-aquic soils are characterized by poor structure, low organic matter, and pronounced shrink-swell, which collectively constrain crop productivity. While legumes are widely promoted for saline soil rehabilitation, their impacts on three-dimensional pore structure, particulate organic matter (POM), and shrinkage remain insufficiently quantified. We evaluated six distinct rotations in the Yellow River Delta using X-ray computed tomography (CT) to quantify and visualize pore structure and POM (fresh vs. decomposed) distributions in the 0–20 cm layer, alongside shrinkage indices and the coefficient of linear extensibility (COLE). In both alfalfa-based and non-alfalfa systems, soybean-based systems significantly increased connected porosity (by 111%–136%), connection probability (by 39.9%–40.6%), fresh POM (by 65.0%–73.9%), and decomposed POM (by 35.1%–71.8%) compared to non-soybean systems (P < 0.05). In addition, relative to the wheat–maize treatment, the wheat–maize/soybean and wheat/alfalfa–maize/soybean treatments significantly reduced COLE by 29.1% and 17.6%, respectively (P < 0.05). Across treatments, lower COLE co-occurred with higher POM (fresh, decomposed) and greater pore connectivity (P < 0.05). These results demonstrate that integrating legumes, especially soybean, improves soil structure and mitigates shrinkage in saline Fluvo-aquic soil. Our findings provide a practical, low-input pathway for optimizing cropping system design to enhance structural functionality and agricultural productivity of coastal saline agroecosystems.

175. 题目: Contrasting responses of bacterial-mediated soil organic phosphorus transformations to varying rates of nitrogen addition in a Cunninghamia lanceolata plantation
文章编号: N26032602
期刊: Applied Soil Ecology
作者: Xiang Zhang, Qiong Zhao, Li-Man Wei, Lin-Hui Wu, Xiang-Min Fang, Yong-Hong Ma, Fu-Sheng Chen
更新时间: 2026-03-26
摘要: Global atmospheric nitrogen (N) deposition is intensifying. Importantly, the rate of this deposition exhibits pronounced spatiotemporal variability. Yet how varying rates of N deposition reshape soil organic phosphorus (P) transformations through bacterial pathways remains unresolved. In a subtropical Chinese fir (Cunninghamia lanceolata) plantation subjected to 10 years of N addition at two levels (N50: 50 kg N ha−1 year−1 and N100: 100 kg N ha−1 year−1), we quantified phosphomonoesterase and phytase activities, functional gene abundances, and bacterial network architecture. Low N addition (N50) elevated acid phosphatase activity by 47.6%, increased available P by 20.5%, and enhanced microbial biomass C and P, without eroding phosphatase gene abundance, thereby sustaining organic P mineralization. In contrast, high N addition (N100) suppressed phytase activity by 56.3%, reduced microbial biomass P by 55.4%, and markedly decreased total bacterial (16S-rRNA), phoC, and phoD gene copies, while restructuring bacterial networks toward reduced complexity and functional redundancy. Despite similar acidification under both N regimes, only N100 induced significant inorganic N accumulation, suggesting that N saturation rather than pH decline drove functional collapse of microorganisms in N100 treatment. Our findings reveal a threshold-dependent bacterial regulation of P cycling, whereby maintaining N inputs below this ecological inflection point is essential for preserving P availability and the functional stability of plantation soils under accelerating N deposition.

176. 题目: Soil nutrients and organic carbon changes in 20-year repeated soil monitoring in hybrid aspen plantations on former agricultural lands
文章编号: N26032601
期刊: Forest Ecology and Management
作者: Natalia Vysotska, Reimo Lutter, Arvo Tullus, Tea Tullus, Reeno Sopp, Alar Astover, Hardi Tullus
更新时间: 2026-03-26
摘要: Afforestation of former agricultural lands is promoted to mitigate climate change. Yet, long-term effects of afforestation on soil quality remain insufficiently studied in Northern Europe. We evaluated changes in soil organic carbon (SOC), total nitrogen (Ntot), pH, and plant-available macro- and micronutrient (P, K, Ca, Mg, Cu, Mn) concentration in a 20-year period from early (5-year) to late (25-year) stand development period in hybrid aspen (Populus tremula × P. tremuloides) plantations on abandoned agricultural lands in Estonia. Soil samples were collected from 49 permanent plots when stands were 5, 15, and 25 years old in the A- and B-horizons. Linear mixed-effects models were applied to identify key stand- and soil-related predictors of change. Between 5 and 25 years, the A-horizon acidified by 0.3 pH units, while SOC (13.7%), Ntot (10.1%), Mg (17.0%), Cu (92%), and Mn (16.6%) increased. In the B-horizon, pH declined by 0.2 units, while Ntot (86%), Cu (192%), and Mn (35%) increased. Most changes occurred during early stand development (5–15 years), while pH, SOC, and Ntot stabilized between 15 and 25 years. Although A-horizon P remained stable, its decline with increasing height growth suggests faster-growing stands drew more heavily on this reserve. Initial soil property values dominated long-term trajectories in both horizons. Repeated soil monitoring over 20 years in hybrid aspen plantations revealed stabilization of SOC and nutrients.

177. 题目: Modeling Variability in Vertical Profiles of Particulate Organic Carbon Flux
文章编号: N26032514
期刊: Geophysical Research Letters
作者: Katherine Taylor, Raffaele Ferrari, B B Cael
更新时间: 2026-03-25
摘要: The vertical flux of particulate organic carbon (POC) from the surface to the deep ocean regulates the ocean carbon uptake, with implications for the Earth's carbon cycle. It is debated in the literature what functional form best describes the attenuation of this flux with depth. The wide scatter found in measurements of the flux has impeded progress on this question. A theoretical model is proposed, which treats this scatter as key information rather than noise. Based on the evidence that the POC flux data follow a lognormal distribution, the model predicts the vertical POC flux profile as a function of three parameters: log-mean and log-standard deviation of the POC export flux, and a depth scaling term consistent with previous functional forms. The model captures the large variability observed in individual POC flux profiles and illustrates that large POC flux events contribute substantially to the vertical transfer of POC.

178. 题目: Valorization of Chinese medicine residues into activated biochars to efficiently dislodge enrofloxacin from aquatic environments: mechanistic insights
文章编号: N26032513
期刊: Journal of Environmental Chemical Engineering
作者: Ze Zhong, Jiachen Chen, Mingliang Sun, Kai Luo, Yuqi Li
更新时间: 2026-03-25
摘要: Enrofloxacin (ENR) is a highly lipophilic and hydrophobic antibiotic that is resistant to degradation in aquatic environments, which can result in serious environmental pollution. In this study, biochars were prepared from Chinese medicine residues of Pueraria lobata (PBC) and Leonurus japonicus (LBC), and potassium hydroxide (KOH)-activated biochars (KPBC and KLBC) were subsequently obtained to remove ENR from aquatic environments. The results indicated that KOH activation markedly increased specific surface areas to 2296.09 m2·g−1 of KPBC and 3210.09 m2·g−1 of KLBC, compared with 3.10 m2·g−1 of PBC and 1.59 m2·g−1 of LBC. Batch adsorption experiments revealed that KPBC and KLBC had maximum adsorption capacities of 594.6 and 743.9 mg·g−1, respectively. Meanwhile, KPBC and KLBC maintained high adsorption stability under different ionic conditions, in the existence of humic acids and in actual water environments and also showed excellent reusability across multiple regeneration cycles. The adsorption processes could be fitted well by using pseudo-second-order kinetic and Freundlich isotherm models. In addition, thermodynamic analysis showed that the adsorption was spontaneous and dominated by physical interactions. The adsorption mechanisms could be mainly attributed to pore filling, π-π interactions, electrostatic attraction, hydrogen bonding and surface complexation by characteristic analysis of activated biochars. In summary, KOH-activated biochars derived from P. lobata and L. japonicus residues offer a green, efficient and promising adsorbent for the ENR removal from aquatic environments.

179. 题目: Molecular-level Removal Mechanism of Manganese Dioxide Oxidation of Sulfamethoxazole Mediated by Hydrochar-Derived Dissolved Organic Matter
文章编号: N26032512
期刊: Water Research
作者: Jiaxing Lu, Yapu Han, Bo Sun, Yue Cao, Sihan Zhang, Qiang Kong, Jian Zhang
更新时间: 2026-03-25
摘要: Biochar-derived dissolved organic matter (DOM) could enhance organic pollutants removal efficiently by manganese dioxide (MnO2). Nevertheless, existing studies have centered chiefly on the effect of pyrochars-derived DOM on organic pollutants removal by MnO2, while study on the corresponding effects of hydrochars-derived DOM (HDOM) is lacking. Herein, this study systematically investigates the capacity and molecular-level mechanism by which HDOM, produced from various feedstocks at different hydrothermal temperatures, enhances MnO2 degradation of sulfamethoxazole (SMX). Results demonstrated that Acorus calamus (AC) HDOM had higher SMX removal compared to Phragmites australis (PA) HDOM, and SMX removal increased with the decrease of hydrothermal temperature. AC160 HDOM had the highest SMX removal (67.87%) and reaction rate (4.40×10−3 L mol−1 min−1), and the SMX removal increased with HDOM concentration enhanced and pH decreased. Mass spectrometry proved that aliphatic compounds rather than polyphenols are the important composition that governed the SMX removal in MnO2/HDOM coupled system. Molecular reaction network analysis found the higher aromatic molecules transformed into lower aromaticity species mainly by oxygen addition pathway during HDOM transformation, which increased O/C ratio. The highest CHOS proportion in AC160 HDOM contributed to the higher electron-donating capacity and enhanced electron transfer between MnO2 and HDOM. This promoted Mn(IV)/Mn(III) oxidation and lattice oxygen activation, thereby boosting •O2⁻ and •OH production and achieving the highest SMX removal. These findings provide a better understanding of molecular-level mechanism and environmental behavior of HDOM in Mn-rich systems during organic pollutant oxidation.

180. 题目: Soil organic carbon in arid and humid grasslands of China: Spatial heterogeneity, driving factors, and future changes
文章编号: N26032511
期刊: Science of the Total Environment
作者: Zihan Kan, Mingming Wang, Jiyuan Liu, Shihang Zhang, Wei Hang, Boyi Song, Yongxing Lu, Hao Guo, Xing Guo, Jungang Yang, Xiaoying Rong, Ye Tao, Xiaobing Zhou, Yuanming Zhang
更新时间: 2026-03-25
摘要: Grassland ecosystems play a crucial role in the global carbon cycle, yet the spatial patterns and drivers of soil organic carbon density (SOCD) across aridity gradients remain insufficiently understood. Here, we used the Carbon Density Dataset of China's Terrestrial Ecosystems (2010s) and applied random forest models to simulate SOCD at two soil depths (SOCD0–20 cm and SOCD0–100 cm) in arid and humid grasslands. We further quantified the contributions of environmental drivers and projected future SOCD dynamics under Shared Socioeconomic Pathways (SSPs). Results showed that SOCD was lower in arid than in humid regions, but due to their vast extent, arid regions contained larger total soil carbon stocks. The 0–20 cm layer accounted for approximately 50% of the SOCD in the 0–100 cm profile. In arid regions, SOCD0–20 cm was mainly controlled by mean annual temperature and soil moisture, while SOCD0–100 cm depended on clay content and total nitrogen. In humid regions, SOCD0–20 cm was strongly influenced by temperature and NDVI, whereas SOCD0–100 cm was regulated by clay and nitrogen. Under future SSP scenarios, SOCD is projected to decline in arid regions but increase in humid regions, indicating an enhanced carbon sink potential. SOCD0–20 cm showed higher variability and lower stability than SOCD0–100 cm. These findings clarify the spatial heterogeneity and depth-dependent controls of grassland SOCD and provide a scientific basis for region-specific soil carbon management, contributing to China's “dual carbon” goals and sustainable grassland policies.