1. 题目: Decoding organic matter sources and controlling factors: A comparative study of lipid biomarker signatures from Northwest Himalayan lakes 文章编号: N25061513 期刊: Ecological Indicators 作者: Sunil Kumar, Soumyashree Behera, Sushma Prasad, Praveen K Mishra, Arshid Jehangir, Ambili Anoop 更新时间: 2025-06-15 摘要: Lipid biomarkers, including n-alkanes, C20 highly branched isoprenoids (HBI), and the pristane-to-phytane (Pr/Ph) ratio in sedimentary organic matter (OM), serve as key proxies for reconstructing past environmental conditions and assessing ecological dynamics in aquatic systems. This study examines surface sediment and vegetation samples from Manasbal Lake and compares the lipid biomarker signatures with previously published data from Renuka and Ahansar Lakes in the NW Himalaya. In Manasbal Lake, aquatic macrophytes exhibit Paq values > 0.4 and average chain length (ACL) values between 25.5 and 27.3, while terrestrial plants show Paq values < 0.4 and ACL values between 27.3 and 30.5.The surface sediments from Manasbal Lake show elevated ACL and terrestrial/aquatic ratio (TAR) values near the eastern inlet, indicating significant terrigenous input via runoff, while Paq > 0.5 in the eastern and western regions suggests enhanced autochthonous productivity and anthropogenic influence. A carbon preference index (CPI) > 1 supports the effective preservation of biogenic OM. The weak correlation between n-alkane distributions and sediment grain size suggests that OM deposition is independent of hydrodynamic sorting. Comparative analysis reveals that Manasbal and Ahansar lakes receive substantial terrestrial and aquatic OM contributions, whereas OM in Renuka Lake is largely microbial. The redox-sensitive Pr/Ph ratio suggests anoxic conditions favour OM preservation. The presence of C20 HBI isoprenoids highlights periphytic algal contributions in these aquatic systems. These findings underscore the utility of lipid biomarkers in tracing OM sources, intrabasinal distribution, and transformation. This data will help in developing strategies for protecting aquatic systems under anthropogenic and environmental pressures.
2. 题目: Inhibition by Dissolved Organic Matter of the Degradation of Purine Compounds by the Sulfate Radical 文章编号: N25061512 期刊: Water Research 作者: Shuangshuang Cheng, Rui Cui, Jinpeng Yu, Yujie Zhao, Xin Yang 更新时间: 2025-06-15 摘要: Dissolved organic matter (DOM) has been known to inhibit the degradation of compounds in advanced oxidation processes but quantitative understanding is lacking. Given the variable concentrations and properties of DOM in real aquatic systems, the concentration-dependent kinetics of compounds degradation were systematically investigated in the presence of 8 DOM isolates separately during UV/peroxydisulfate (UV/PDS) process. Due to the ubiquitous presence of purine compounds in aquatic environments, guanine was selected as a model purine compound. The concentration-dependent kinetics of guanine degradation exhibit consistent across all 8 DOM. The inhibition percentage (IP) exhibited an initial rapid enhancement with increasing DOM concentrations from ∼0 to 1.0 mgC L⁻¹, following by a gradual rise at higher DOM concentrations (∼2–5 mgC L⁻¹) among 8 DOM isolates. The elaborated kinetics model including radical oxidation and reverse-reduction process was then applied in this study, which successfully quantifies the contribution of guanine degradation. During UV/PDS process, the sum of and decreased with increasing DOM concentration among 8 DOM isolates. It shows minimal variation across different types of DOM at specific DOM concentrations. The contribution to (lack of) guanine degradation by reverse-reduction process (kq) shows an initial significant increase followed by a gradual decrease with increasing DOM concentrations. The kq values were found to differ significantly among 8 DOM isolates. The concentration of DOM ([DOM]1/2) at which the reverse reduction ratio is 50% were in the range of 0.14–0.88 mgC L−1 for 8 tested DOM. [DOM]1/2 values show negative correlations with specific absorbance at 254 nm (SUVA254) (R2 = 0.70) or total antioxidant capacity (TAC) (R2 = 0.92), indicating that the overall reactivity between guanine’s intermediate and DOM is mainly attributed to the aromatics and antioxidant moieties in DOM. The research findings have significant guiding implications for predicting the degradation rates of compounds in actual water and improving compounds removal efficiency.
3. 题目: Biogeochemical-Argo Floats Reveal Seasonality of the Biological Carbon Pump Influenced by the Lofoten Basin Eddy 文章编号: N25061511 期刊: Geophysical Research Letters 作者: D Koestner, S Clayton, P Lerner, A E Jones-Kellett, S L Walker 更新时间: 2025-06-15 摘要: The Lofoten Basin Eddy (LBE) is a persistent topographically constrained anticyclonic eddy in the Norwegian Sea. Considering its local, dynamically distinct state, we test the hypothesis that the LBE has unique biogeochemical signatures. Using satellite observations and a 12-year Biogeochemical-Argo float record, we constructed a climatological view of the annual biogeochemical cycle within and surrounding the LBE. The biological carbon pump influenced by the LBE was less effective than surrounding waters, particularly during late spring. Particulate organic carbon export out of the productive zone was hindered during summer and likely associated with enhanced respiration and slower particle sinking speeds. Enhanced export into the twilight zone was also observed and consistent with shoaling of deep mixed layers in early spring, production of large particles in late summer, and subduction in late autumn; however, these mechanisms appear to be accompanied by enhanced remineralization within the LBE influence zone, highlighting the biogeochemical complexity of eddies.
4. 题目: Enhanced denitrification performance via biochar-mediated electron shuttling in Pseudomonas guariconensis: mechanistic insights from enzymatic and electrochemical analyses 文章编号: N25061510 期刊: Environmental Pollution 作者: Anhang Li, Zeyu Wang, Changjie Shi, Nan Li, Mengwei Bai, Jiachao Yao, Dzmitry Hrynsphan, Haifeng Qian, Sihan Hu, Jun Wei, Jun Chen 更新时间: 2025-06-15 摘要: Nitrogen pollution constitutes a critical environmental challenge for aquatic ecosystems, where biological denitrification serves as a critical mechanism for nitrogen removal in wastewater treatment plants (WWTPs). Pseudomonas guariconensis, a key denitrifying bacterium in WWTPs, demonstrates stable symbiotic relationships with organic carbon substrates under operational conditions. This study investigated the biochar-mediated enhancement mechanism of denitrification performance using Pseudomonas guariconensis strain XYH-2. Experimental results revealed that 0.5 % (w/w) biochar addition significantly improved denitrification efficiency, elevating NO3−-N removal from 39 % to 94 % within 16 h while reducing N2O accumulation by 81.7 % (from 837 to 153 ppm). Electrochemical characterization and extracellular polymeric substances (EPS) analysis demonstrated biochar's role as an electron shuttle, evidenced by a 48.5 % increase in electron transfer system activity (ETSA) and enhanced redox currents. Notably, biochar stimulation elevated the activities of four key denitrifying enzymes: nitrate reductase (NAR, +75.6 %), nitrite reductase (NIR, +25.4 %), nitric oxide reductase (NOR, +33.3 %), and nitrous oxide reductase (N2OR, +159.4 %). Structural characterization revealed biochar-induced conformational modifications in N2OR that enhanced substrate binding affinity, particularly explaining the dramatic N2O mitigation. These findings provided mechanistic insights into biochar-bacteria synergism, proposing an effective strategy for optimizing denitrification processes in nitrogen-contaminated wastewater treatment systems.
5. 题目: Soil carbon and nitrogen changes due to soil particles redistribution caused by photovoltaic array 文章编号: N25061509 期刊: Frontiers in Environmental Science 作者: Feiyan Zhao, Zhongju Meng, Yang Liu, Peng Li, Guodong Tang 更新时间: 2025-06-15 摘要: There is an inevitable relationship between the size of soil particles and the distribution of organic matter. The soil texture in desert photovoltaic areas is poor, with variations in soil particle size and organic matter. This study explores the heterogeneity of soil particle size and organic matter distribution at different zonal scales, aiming to clarify the impact of photovoltaic array construction on microtopography and, consequently, on these indicators. This will facilitate precise vegetation restoration based on the distribution of nutrients within the region. Baced on the Kubuqi Desert photovoltaic area as the research area, the soil particle size in the 0–30 cm soil layer and the distribution of soil organic matter in the main particle size range (<250 μm, <500 μm) in this area were analyzed. Fine sand (particle size 100–250 μm) was the main component of the soil; the carbon and nitrogen stocks in the upper 0–30 cm of soil diminished linearly with escalating wind speed gradient, from 70.76 Mg C ha−1 to 53.82 Mg C ha−1 and from 13.96 Mg N ha−1 to 8.12 Mg N ha−1. The total carbon and nitrogen levels in the two soil particle sizes, together with their contribution to total soil organic carbon, diminished as the wind speed gradient intensified, with the reduction in organic carbon content becoming stronger. The organic carbon content of soil particles <250 μm accounted for 63.7%–98.6% of the total soil organic carbon, while that of particles 250μm–500 μm only accounted for 3.32%–33.34%. SOC was significantly higher in the 0–5 cm layer than in the 5–30 cm layer in all areas of the photovoltaic array. Wind causes changes in sand particle transport in PV arrays, and may also alter the microclimate environment leading to differences in soil decomposition cycling processes, which can exhibit uneven organic carbon and nitrogen distribution between particles. Our research demonstrates the internal distribution of soil carbon and nitrogen reserves in each region of the photovoltaic array, establishing a robust foundation for subsequent vegetation restoration and plant species selection in each region, thereby implementing the “photovoltaic + ecological” governance model.
6. 题目: Smart municipal wastewater treatment sludge management: Enhancement of biogas production from anaerobic digestion amended by optimized sludge-derived biochar 文章编号: N25061508 期刊: Science of the Total Environment 作者: Rahman Zeynali, Mohsen Asadi, Phillip Ankley, Hannah Mahoney, Markus Brinkmann, Bishnu Acharya, Kerry McPhedran, Jafar Soltan 更新时间: 2025-06-15 摘要: Improving anaerobic digestion (AD) efficiency at municipal wastewater treatment plants (MWTPs) is essential for enhancing renewable energy recovery and achieving sustainable sludge management, especially in cold climates where AD performance is often limited. This study introduces an integrated approach using phosphoric acid-activated sludge-derived biochar (ASBC), produced from thickened waste-activated sludge (TWAS), to enhance biogas production. The effects of ASBC particle size and concentration were evaluated using response surface methodology (RSM), while computational fluid dynamics (CFD) simulations were applied to optimize reactor mixing and minimize dead zones. The optimized condition (15 g/L ASBC, 500 μm particle size; R-500-15) resulted in the highest biogas yield of 285 mL/g volatile solids (VS), a 48 % increase compared to the control. Additionally, the methane content in biogas increased to 68 %, which was 9.6 % higher than the control sample (62 %). Microbial community analysis showed that the bacteria family Peptostreptococcaceae (known for anaerobic fermentation) and archaea family Methanomicrobiales (known for methane production) had increased relative abundances of 0.760 and 30.2 % relative to the control in this optimized ASBC treatment. CFD modelling confirmed that tailored intermittent mixing (60 rpm for 55 s every 5 min) effectively reduced reactor dead zones to 13 %, contributing to improved substrate distribution and microbial interaction. This work demonstrates a cost-effective and sustainable strategy to optimize AD performance using waste-derived biochar and hydrodynamic enhancement. The approach supports energy-positive wastewater treatment and aligns circular economy and climate action goals, offering valuable guidance for MWTPs seeking to improve operational efficiency and environmental performance.
7. 题目: Integrated Influence of Sulfide Modified Nanoscale Zero-Valent Iron on Selective Removal towards Algal Extracellular Polymeric Substances 文章编号: N25061507 期刊: Journal of Environmental Chemical Engineering 作者: Cheng-Cheng Ji, Shao-Kang Deng, Xin-Hua Xu, Li-Hua Cheng 更新时间: 2025-06-15 摘要: Microalgae-based bioremediation was an alternative to traditional biological wastewater treatment. However, its application was constrained by limited microalgal metabolic activity, slow growth rates in wastewater matrices, and excessive accumulation of extracellular polymeric substances (EPS) in effluent. This study demonstrated that sulfide-modified nano-zero-valent iron (SNZVI) integration into microalgae cultivation systems synergistically enhanced biomass production by 70.3% while reducing EPS content by 55.2%. Kinetic analysis demonstrated that controlled sulfidation (S/Fe=0.028) significantly improved dissolved organic carbon (DOC) removal, achieving a rate constant (k2) of 0.199 g (mg C)-1 h-1, as 1.65 times higher than that of NZVI. Additionally, it doubled the aromatic compound adsorption capacity (0.909 cm-1·L·g-1) and enhanced the conversion of polyphenolic-like substances in EPS transformation by 82%. Crucially, surface sulfur speciation (S2−/S22− molar ratio) exhibited a strong linear correlation (R2 0.95) with aromatic contaminant degradation rates. Meanwhile, the removal rates of UV254 (k1, k2) were related to the electron transfer resistance and double-layer capacitance of SNZVI determined by electrochemical tests, indicating that aromatic substances were more likely to accept electrons provided by SNZVI for conversion, indicating that aromatic substances were more likely to accept electrons provided by SNZVI for conversion. These findings established SNZVI as a dual-function enhancer, simultaneously boosting microalgal vitality and enabling electron-mediated EPS conversion. Our work provided a theoretical basis for the rational design of metal-based nanoparticles in future microalgae water treatment.
8. 题目: Enhancing Digestate-Based Bioponics through Ceramsite Addition with and without Biochar: Effects on Water Quality, Nutrient Recovery, Heavy Metal Removal, and Microbial Community Composition 文章编号: N25061506 期刊: ACS ES&T Engineering 作者: Sumeth Wongkiew, Suchana Amnuaychaichana, Kavisara Srithadindang, Waroton Paisuwan, Anawat Ajavakom, Chongrak Polprasert, Pongsak Lek Noophan, Nuta Supakata, Thammarat Koottatep, K C Surendra, Samir Kumar Khanal 更新时间: 2025-06-15 摘要: Digestate is a nutrient-rich substrate for bioponics, and ceramsite is a natural adsorbent for heavy metal (e.g., Cu and Zn) removal. This study primarily examined the potential of incorporating ceramsite with and without biochar into a digestate-based bioponic system for growing Green Oak lettuce. The amendment of digestate enhanced initial total nitrogen and phosphorus levels and organic matter while increasing the Cu and Zn levels in the bioponic water and plant biomass. The incorporation of ceramsite reduced organic matter and Cu and Zn levels in both water and plants, achieving higher efficiency when combined with biochar. The combination of ceramsite and biochar reduced Cu and Zn concentrations in bioponic water by 40.3% and 64.6%, respectively, compared to the digestate-only system, while ceramsite alone achieved 13.5% and 10.5% reductions, indicating a synergistic effect. Nitrogen and phosphorus recovery did not differ significantly among all conditions. Plant roots, digestate, ceramsite, and biochar harbored different microbial communities. In digestate-based bioponics, keystone microbes were identified in each medium, such as Bacillus (digestate), SH-PL14 (ceramsite), Prosthecobacter (biochar), and Ideonella (plant roots), indicating their key roles in organic degradation, heavy metal removal, and nutrient recovery. Microbial functional profiling using FAPROTAX revealed distinct roles, including aerobic ammonia oxidation in ceramsite and nitrate respiration and fermentation in biochar, supporting nitrogen cycling and organic degradation. Therefore, the use of ceramsite, with and without biochar, as an adsorbent offers a sustainable, nature-based solution for maintaining water quality and enhancing nutrient recovery in bioponics, leveraging digestate as a nutrient source.
9. 题目: Odor emissions and humification during composting of pig manure and cornstalks: Role of mixing proportions 文章编号: N25061505 期刊: Journal of Environmental Chemical Engineering 作者: Yixun Shi, Xuhan Gu, Jingchen Song, Hui Li, Cun Sun, Jiahui Wang, Jijin Li, Wen Liu, Guoxiang Bu, Hongbin Wang, Shuyan Li 更新时间: 2025-06-15 摘要: This study investigated odor (i.e. ammonia and hydrogen sulfide) emissions and humification in co-composting of pig manure and cornstalks. Effects of feedstock mixing proportions on composting performance were evaluated. Pig manure and cornstalks were thoroughly blended with the ratio of 3:1, 6:1 and 9:1 (wet weight), respectively. Results showed that the thermophilic stage was long enough in all treatments to satisfy maturity, non-phytotoxicity and sanitation requirements. Odor emissions especially ammonia emission aggravated with the decrease of cornstalks addition. In addition, matrix oxygen content was the main factor affecting odor emissions. The multiple nonlinear regression models could better simulate odor emissions than the linear ones. Pig manure and cornstalks mixed with 6:1 improved the humic acid/fulvic acid to 12.22 and strengthened the earlier lignin humification and later Maillard reaction to promote the composting humification and stability by the two-dimensional correlation spectroscopy of infrared spectrum. Additionally, mixing pig manure and cornstalks at a ratio of 3:1 improved the compost quality index and also mitigated NH3 and H2S emissions by 64% - 71% and 30% - 32%, respectively. Thus, comprehensive evolution of odor emissions, compost humification and stability, pig manure and cornstalks co-composted with the ratios of (3-6):1 were recommended to be applied in practice.
10. 题目: Hydrophilic Organic Compound Migration in Biochar-Amended Stormwater Filters with Dynamic Conditions and Varied Background Dissolved Organic Carbon Contents. 文章编号: N25061504 期刊: Environmental Science & Technology 作者: James Conrad Pritchard, Yeo-Myoung Cho, Stephanie Spahr, Richard G Luthy 更新时间: 2025-06-15 摘要: Urban stormwater runoff carries dissolved, hydrophilic urban pollutants into surface waters and aquifers, impairing human and aquatic health and threatening beneficial stormwater uses, such as augmentation of drinking water supplies. Black carbon-amended stormwater filters have been shown to remove dissolved metal and organic contaminants from urban stormwater runoff, and 1-dimensional intraparticle pore diffusion limited-sorption models have been validated for predicting filter performance under constant flow and influent conditions. However, as stormwater runoff is quite variable, it is important to understand how dynamic conditions and varied background dissolved organic carbon (DOC) affect the filter performance. This study investigates how dynamic flow and influent contaminant loading and variable background DOC conditions affect compound migration and transport modeling in biochar-amended stormwater filters through a series of four column experiments. Dynamic flow and influent contaminant loading conditions substantially affect contaminant migration, which is predicted by using a previously validated transport model with previously determined sorption and apparent intraparticle tortuosity parameters. Increased background DOC (from 3 mg C L-1 to 18 mg C L-1) accelerated contaminant migration. Fitting the transport model to observed breakthrough curves and equilibrium batch isotherm experiments reveals that increasing the DOC increases the intraparticle diffusion hindrance, reduces the sorption capacity of the carbon, and increases the linearity of the isotherms. Kinetic limitations of contaminant removal are shown to be exaggerated at higher DOC conditions by quantifying the impacts of DOC and contact time on filter performance. This study provides confidence in the robustness of the contaminant transport model predictions for simulating dynamic conditions and offers insight into the impact of dynamic conditions and background DOC on contaminant removal in biochar-amended stormwater filters.
11. 题目: Iron‐Organic Carbon Interactions in Wetlands: Implications for Wetland Carbon Preservation Under Global Changes 文章编号: N25061503 期刊: Global Change Biology 作者: Xiaojuan Feng, Yunpeng Zhao, Houquan Wang, Chengzhu Liu 更新时间: 2025-06-15 摘要: As a tremendous global carbon reservoir, wetlands play a pivotal role in mediating climate change. Organic carbon (OC) stored in wetlands is usually considered to be dominated by particulate organic carbon (POC) devoid of mineral protection. However, recent studies have revealed that reactive iron (Fe) (hydr)oxides are more abundant than previously recognized in wetlands and may stabilize up to 40% of soil organic carbon (SOC). Yet the significance of Fe‐OC interactions in wetland carbon preservation and their responses to global changes remain insufficiently understood. Here this review summarizes recent advances in three key aspects related to Fe‐OC interactions in wetlands: microbe‐ and plant‐mediated biogeochemical processes regulating the formation and accumulation of reactive Fe (hydr)oxides in wetland soils; characteristics of Fe‐OC interactions and their implications for wetland carbon preservation; and the response of Fe‐OC interactions to global changes including drainage and warming. We also highlight future research directions and potential strategies related to wetland Fe‐OC interactions, which warrant better recognition in the protection and restoration of wetland carbon reservoirs. These advances underscore that mineral protection by reactive metal oxides is an underappreciated mechanism of SOC preservation in wetlands, potentially improving our understanding of wetland carbon dynamics under global changes.
12. 题目: Black carbon structuring marine microbial activities and interactions: a micro- to macro-scale interrogation. 文章编号: N25061502 期刊: Environmental Science and Pollution Research 作者: Amira Saidi, Luca Zoccarato, Giovanni Birarda, Xavier Mari, Markus Weinbauer, Lisa Vaccari, Mauro Celussi, Francesca Malfatti 更新时间: 2025-06-15 摘要: Black carbon (BC) consists of partially combusted organic matter deriving from biomass and fuels burning. According to the IPCC's reports, BC emissions are the second-largest contributor to global warming after CO2. BC enters the marine system via dry deposition or river run-off. Once in the sea, BC has the potential to affect nutrient biogeochemical cycles. In a series of four incubation experiments (Adriatic Sea and Ligurian Sea) and a pilot study, we have challenged the microbes with heavy loads of BC (24 mg L-1) in order to study the short-term BC effect on microbial dynamics and activities. Upon BC amendment, heterotrophic prokaryotes increased in abundance while viruses decreased. At the microscale, microbes became attached to BC particles, very heterogeneous in shape and size and enriched in proteins over time; these findings were confirmed by Fourier transform-IR spectroscopy and atomic force microscopy. Enzymatic degradative activities, proteases, and alkaline phosphatases were suppressed in the BC treatments despite an enhancement in prokaryotic carbon production. The 16S rRNA gene amplicon sequencing analysis did not show a significant shift in the microbial communities. Despite this, indicator species analysis revealed that Arcobacter and Pseudoalteromonas genera were statistically associated with the BC treatment at 48 h, thus suggesting their adaptive strategies to utilize BC. Our findings reveal that BC has the potential to stimulate intense carbon flow through microbial activity in the sea. Future studies should take account of the contribution of anthropogenic carbon, BC, into the marine biogeochemical C cycle.
13. 题目: Downward movement of nitrate stimulates losses of soil organic carbon in deeper soil layers 文章编号: N25061501 期刊: Proceedings of the National Academy of Sciences 作者: Xiaotang Ju, Chong Zhang, Xue Tian 更新时间: 2025-06-15 摘要: Zhou et al. (1) recently reported the dynamics of soil organic carbon (SOC) in China’s upland croplands from 1980 to 2023, with significant SOC accumulation in the upper 0 to 60 cm soil layers but with co-occurring SOC depletion in the 60 to 100 cm subsoil layers, based on large-scale resampling campaign (site by site). They attributed the subsoil SOC losses primarily to accelerated decomposition driven by climate warming over the past four decades using model-based analysis. Results from our 15-y long-term field experiment (2006 to 2021) corroborate this pattern of vertical SOC divergence (2), i.e., the net accumulation of SOC stock in the upper 0 to 40 cm soil layers but net losses in the deeper 40 to 100 cm soil layers (Fig. 1A). We further propose that another important cause of these losses is the positive priming effect induced by the downward movement of nitrate, which stimulates SOC decomposition in deeper soil layers. Our long-term field experiment provides direct evidence supporting this mechanism.
14. 题目: From the top: surface-derived carbon fuels greenhouse gas production at depth in a peatland 文章编号: N25061409 期刊: Biogeosciences 作者: Alexandra Hedgpeth, Alison M Hoyt, Kyle C Cavanaugh, Karis J McFarlane, Daniela F Cusack 更新时间: 2025-06-14 摘要: . Tropical peatlands play an important role in global carbon (C) cycling, but little is known about factors driving carbon dioxide (CO2) and methane (CH4) emissions from these ecosystems, especially production in deeper soils. This study aimed to identify source material and processes regulating C emissions originating deep in three sites in a peatland on the Caribbean coast of Panama. We hypothesized that (1) surface-derived organic matter transported down the soil profile is the primary C source for respiration products at depth and that (2) high lignin content results in hydrogenotrophic methanogenesis as the dominant CH4 production pathway throughout the profile. We used radiocarbon isotopic values to determine whether CO2 and CH4 at depth are produced from modern substrates or ancient deep peat, and we used stable C isotopes to identify the dominant CH4 production pathway. Peat organic chemistry was characterized using 13C solid-state nuclear magnetic resonance spectroscopy (13C-NMR). We found that deep peat respiration products had radiocarbon signatures that were more similar to surface dissolved organic C (DOC) than deep solid peat. These results indicate that surface-derived organic matter was the dominant source for gas production at depth in this peatland, likely because of vertical transport of DOC from the surface to depth. Lignin, which was the most abundant compound (55 %–70 % of C), increased with depth across these sites, whereas other C compounds like carbohydrates did not vary with depth. These results suggest that there is no preferential decomposition of carbohydrates but instead preferential retention of lignin. Stable isotope signatures of respiration products indicated that hydrogenotrophic rather than acetoclastic methanogenesis was the dominant production pathway of CH4 throughout the peat profile. These results show that deep C in tropical peatlands does not contribute greatly to surface fluxes of carbon dioxide, with compounds like lignin preferentially retained. This protection of deep C helps explain how peatland C is retained over thousands of years and points to the vulnerability of this C should anaerobic conditions in these wet ecosystems change.
15. 题目: First Signs That National Cropland Organic Carbon Loss Is Reversing in British Topsoils 文章编号: N25061408 期刊: European Journal of Soil Science 作者: L Bentley, A Thomas, A Garbutt, B Williams, S Reinsch, I Lebron, M Brentegani, P Keenan, C Wood, S M Smart, P A Henrys, B J Cosby, B A Emmett, D A Robinson 更新时间: 2025-06-14 摘要: High rates of soil organic carbon (SOC) loss from cropland soils are well known, contributing to climate change and compromising soil and ecosystem health. Stabilising and reversing the loss of organic matter from cropland soils is a challenge for all nations to meet the United Nations Sustainable Development Goals. Sustainable land management (SLM) has been promoted as a mechanism of achieving this, but to date, there is no evidence of positive impacts at scale. Here we show the first signs of the reversal of soil carbon loss in cultivated topsoils in Great Britain, following a period of reported SLM uptake, using 40+ years of national soil monitoring from the UKCEH Countryside Survey. Following a prolonged historic decline at rates of −0.16 t ha−1 year−1, there was a significant increase in cropland topsoil SOC stocks (0–15 cm) from 2007 to 2019–22 with an accrual rate of 0.17 t ha−1 year−1, approximately 0.74 MtC year−1 nationally. We discuss reported management shifts in Great Britain in the corresponding period and identify a reduction in conventional tillage and reduced straw removal as potential drivers, but highlight additional evidence gaps worthy of consideration. This increase in topsoil SOC may represent net carbon sequestration or carbon redistribution (geographic or vertical) but nevertheless demonstrates that topsoil properties can be restored at scale and offers hope that a concerted effort by land managers can halt, and potentially reverse, SOC loss from cropland soils.
16. 题目: Microplastic Leachates in Farmland: Impact of Acid Rain on DOM Characteristics and Metal Release 文章编号: N25061407 期刊: Environmental Science: Processes & Impacts 作者: Yinghui Xu, Yifan Mao, Xuzhi Li, Mei Li, Ting Guo, Haibo Zhang, Yimin Cai 更新时间: 2025-06-14 摘要: Microplastics (MPs) in farmland soil may leach dissolved organic matter (DOM) and metal-based additives during rainfall and irrigation processes, potentially impacting agroecosystems. This study investigated the leaching characteristics of MPs commonly found in agricultural soils and irrigation water under varying acid rain conditions. The MPs leachates were analyzed for their physicochemical properties, three-dimensional fluorescence characteristics, and heavy metal release. The results revealed that most MPs leachates exhibited neutral to alkaline pH, likely due to the dissolution of inorganic fillers such as CaCO₃. Dissolved organic carbon (DOC) leaching varied by polymer types, with biodegradable MPs and PET-based MPs exhibiting significantly higher DOC concentrations than other MPs. Heavy metal analysis identified antimony (Sb) and zinc (Zn) as the dominant leached metals, particularly in Gr-carpet, C-Curtain, and G-cover. Evidence showing Sb concentrations in these MPs leachates exceed China’s drinking water safety thresholds by 5.76-26.7 times. Additionally, DOC release was pH-dependent, with neutral conditions enhancing organic matter release, whereas acidic conditions promoted metal leaching, particularly manganese (Mn) and Zn. Correlation analysis suggested that Sb and arsenic (As) interacted with MPs-derived organic additives and amide/phenol-like substances, indicating potential metal-organic complexation. This study systematically investigates the leaching characteristics of MPs under simulate acid rain conditions, which helps to better assess the environmental impact and potential risks of MPs.
17. 题目: Exotic plant invaders as ecosystem engineers: Impacts on blue carbon accumulation by altering carbon emissions and thermal responses 文章编号: N25061406 期刊: Limnology and Oceanography 作者: Guangliang Zhang, Junhong Bai, Jichen Qiu, Yuhao Xu, Yujia Zhai, Shengrui Wang 更新时间: 2025-06-14 摘要: Exotic plant invaders frequently function as ecosystem engineers, significantly influencing carbon cycling within native ecosystems. However, the impact of invasive species on carbon emissions and the thermal response of belowground soil organic carbon (SOC) decomposition has not been thoroughly examined. This gap in knowledge poses challenges for managing blue carbon sequestration in coastal salt marshes threatened by invasive plants. Here, we conducted both field investigations and microcosm experiments to assess the effects of a decade‐long invasion by Sporobolus alterniflorus on soil CO2 emissions, SOC decomposition rates, and their sensitivity to temperature variation (Q10). Our results showed that the CO2 emission and its Q10 from invaded soils were generally lower compared to native soils. Changes in soil pH, soil water content, and the ratio of dissolved organic carbon (DOC) to SOC attributable to plant invasion greatly affected CO2 emission, SOC decomposition, and Q10. Microcosm experiments verified the reduced SOC decomposition rates and Q10 values in invaded soils. Additionally, Q10 showed a significant negative correlation with the proportion of labile carbon in soils, supporting the carbon‐quality temperature hypothesis to explain the observed changes in Q10 after plant invasions. Overall, our findings suggest that decreased CO2 emissions and SOC decomposition rates are critical processes driving rapid SOC accumulation in coastal salt marshes following the invasion of S. alterniflorus. These results enhance our understanding of SOC sequestration dynamics in coastal blue carbon ecosystems in the context of exotic plant invasions.
18. 题目: Heteroatoms in Dissolved Organic Matter: Their Role in Adsorption and Dynamic Assembly on Activated Carbon 文章编号: N25061405 期刊: ACS ES&T Water 作者: Jian Liu, Shaohua Chen, Ying Xu, Mengyi Shi, Kai Zhang, Othman Al-Mashaqbeh, Jianzhi Huang 更新时间: 2025-06-14 摘要: The properties of dissolved organic matter (DOM) can significantly affect its adsorption response to activated carbon (AC). Despite extensive studies, the key molecular properties of DOM that govern its adsorbability and assembly behavior on the AC surface remain poorly understood. Here, we investigated DOM-AC interactions using three different secondary effluent organic matter samples through a combination of Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and machine learning (ML). The results showed that heteroatoms (N/S) were the key factors influencing DOM molecular adsorbability on AC, with N/S-containing molecules showing preferential adsorption compared to N/S-free molecules. Furthermore, analysis of temporal molecular behavior revealed a two-stage sequential molecular fractionation process: N-containing molecules exhibited rapid preferential adsorption in the initial stage, while S-containing molecules became preferentially adsorbed in the subsequent phase. This sequential molecular behavior might involve a transition from bare AC-DOM dominated adsorption to DOM-DOM interaction dominated adsorption. These molecular-level insights advance our understanding of DOM-AC interactions and provide new criteria for optimizing AC-based water treatment processes.
19. 题目: Reaction Sequence of the UV/H2O2 System on the Suwannee River Dissolved Organic Matter with Complex Molecular Composition 文章编号: N25061404 期刊: ACS ES&T Water 作者: Fanju Kong, Feiyan Fang, Weiming Chen 更新时间: 2025-06-14 摘要: Hydroxyl radicals (HO•) generated from ultraviolet radiation-activated hydrogen peroxide are highly reactive toward most organic matter and are commonly used to treat wastewater. However, dissolved organic matter (DOM) in municipal or industrial wastewater contains thousands of organic species; the sequence of reactions of HO• with many of them is not well understood, leading to ineffective consumption of oxidants in practice. We use Fourier transform ion cyclotron resonance mass spectrometry to investigate the reaction sequence of HO• with DOM and elucidate the mechanisms of its oxidative degradation by HO•. Early in the reaction, we found that HO• preferentially removed highly unsaturated DOM with a low degree of oxidation (618 species, accounting for 64.2% of total low-oxygen DOM species in SRNOM), whereas later in the reaction, HO• removed high-oxygen (but still highly unsaturated) DOM (1539 species, accounting for 62.9% of total high-oxygen DOM species in SRNOM) but more slowly. In the early stages, DOM was removed through pathways such as hydroxylation, carboxylation and dealkylation; later, DOM was removed mainly through dehydroxylation and decarboxylation. We provide a theoretical basis for using advanced oxidation processes dominated by HO• to degrade complex DOM from wastewater.
20. 题目: Long-term agroforestry enhances soil organic carbon pools and deep soil carbon sequestration in the Indian Himalayas 文章编号: N25061403 期刊: Frontiers in Environmental Science 作者: Swarnashree Barman, Ranjan Bhattacharyya, Charan Singh, A C Rathore, Vibha Singhal, D R Biswas, Nayan Ahmed, Shrila Das, Sandeep Kumar, S L Jat, T K Das, Soora Naresh Kumar, Avijit Ghosh, Fazal Ullah, Hosam O Elansary, Muhammad Nazim, Adil A Fickak, Mohamed A Rashwan, Ihab Mohamed Moussa 更新时间: 2025-06-14 摘要: Despite agroforestry has large potential for soil organic carbon (SOC) sequestration, limited information is available on SOC pools and deep SOC sequestration as affected by agroforestry systems. Potential of long-term (15 years) agroforestry systems to store SOC was assessed in the foot hills of the north western Indian Himalayas. The study was carried out during 2009–2023 and soil samples were taken from four depths, viz. 0–15, 15–30, 30–45, 45–60 cm in Bhimal (Grewia optiva L.) and Mulberry (Morus alba L.) based agroforestry system under cowpea-toria based cropping systems and turmeric as ground storey crop. Results showed that in surface soil (0–15 cm), plots with mulberry + cowpea (Vigna unguiculata L.)-toria (Brassica campestris L.) (T7) had maximum C stock (21.35 Mg C ha−1) which was similar to mulberry + turmeric (Curcuma longa L.) (T6) plots. In deep soil layer (30–60 cm), plots under T7 had 33.52 Mg C ha-1 which was significantly higher than farmers’ practice cowpea-toria (T4). The results revealed that M. alba L. based agroforestry practices had 33%, 18% and 8% higher labile C concentration than (cultivated fallow land) (T9), T5 and T4 plots, respectively, in 0–15 cm soil depth. Recalcitrant C was maximum in T7 (4.49 g kg−1) plots. In the 0–30 cm layer, C accumulation rate ranged from 0.27 Mg C ha−1yr−1 to 0.99 Mg C ha−1y−1. Maximum C accumulation was found in T7 plots which was 160% and 135% higher than the farmers’ practise T4 plots and sole mulberry plantation (T5) plots. In the surface soil (0–15 cm), the treatment T7 had approximately 33% higher carbon management index (CMI) value compared with the farmers’ practise T4 plots. Thus, adopting M. alba L. based agroforestry practices has great potential for improving higher carbon stock in deep soil layer and can be recommended for sustainable management practices in the region, and it also could be considered as a strategy to restore degraded land, which is vital for food security, livelihood enhancement, and overall preserving the environmental services.
