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261. 题目: Catchment-driven trend of dissolved organic matter characteristics in the Hailar River, China
文章编号: N24091714
期刊: Applied Geochemistry
作者: Sen Chai, Xin Zhang, Fei Xie, Xingjun Zhou, Changwei Lü
更新时间: 2024-09-17
摘要: The association of dissolved organic matter (DOM) with natural watershed backgrounds and anthropogenic activities is crucial for environmental assessment and sustainable development of basins. This study investigated the catchment-driven trend of DOM characteristics in the Hailar River basin, China. The results identified three fluorescent components through EEM-PARAFAC models: a terrestrial humic-like component (C1), a humic-like component related to microbial activity (C2), and a UVA humic-like component (C3), which were influenced by Cl and HCO derived from rock weathering. The contents of water-extractable organic carbon (WEOC) extracted from soils surrounding the watershed significantly correlated with the concentrations of DOC and COD. Furthermore, COD exhibits heightened sensitivity to precipitation and temperature fluctuations, revealing the synergistic effects of environmental factors and natural background. The hydrochemical composition and DOM characteristics are predominantly influenced by their origins from the Greater Khingan forests, indicating a catchment-driven trend of DOM in the studied river. What's more, COD in Hailar river basin was mainly controlled by refractory dissolved organic matter (RDOM). This research underscores the need for context-specific environmental standards rather than a “one-size-fits-all” approach and offers scientific insights and methodologies for the rational assessment of water quality and aquatic ecosystem health in similar riverine systems.

262. 题目: Tidal scale dissolved inorganic and particulate organic carbon dynamics in a tropical estuary
文章编号: N24091713
期刊: Marine Chemistry
作者: Mohammad Atif Khan, Sanjeev Kumar, Rajdeep Roy, Satya Prakash, Aneesh Lotliker, Sanjiba Kumar Baliarsingh
更新时间: 2024-09-17
摘要: Dissolved inorganic carbon (DIC) and particulate organic carbon (POC) dynamics in the world's estuaries have been studied extensively at monthly, seasonal, and annual time scales with particular focus on their concentrations and export fluxes to the coastal oceans. However, given the dynamic nature of the estuaries, the effect of tidal and diel cycles on the processes modulating DIC and POC dynamics remains obscure. To decipher the biogeochemical processes at tidal scale, DIC and POC concentrations and their carbon and nitrogen isotopic compositions were measured across the salinity gradient at every high and low tide for nine consecutive days (14–23 October 2019) in the Mahanadi estuary, a tropical estuary at the east coast of India. Showing contrasting differences across salinity gradient in DIC, POC and their isotopic compositions, DIC and POC were significantly different during high and low tide in the mixing zone only during spring duration. This showed the effect of spring-neap tidal cycle owing to water level fluctuations and mixing intensity in the estuarine mixing zone. Linear least-squares regression models indicated carbonate and/or silicate weathering by biogenic CO to be the probable DIC source in the freshwater region of the estuary. Deviations of observed DIC concentrations and δC from the conservative mixing values suggested pronounced alteration of DIC source signature in the mixing zone. A process-based model approach aimed at delineating possible biogeochemical processes affecting DIC dynamics indicated calcite dissolution during low tide and calcite precipitation during high tide to be dominant processes in the mixing zone. Additionally, signatures of more than one simultaneous biogeochemical process modulating the DIC dynamics were also observed. POC pool in the mixing zone was largely influenced by its removal through rapid remineralization during both high and low tides. Graphical plots also showed that POC in the mixing zone and at the saline location was significantly affected by processes such as degradation, whereas it was only slightly affected in the freshwater region of the estuary. δC, along with the C/N ratio of POM, indicated that C3 plants and/or their derived soil were the major source of POM in the freshwater, whereas the higher contribution of riverine POM and marine phytoplankton was observed in the mixing zone and saline location, respectively.

263. 题目: Nutrient-loaded seagrass litter experiences accelerated recalcitrant organic matter decay
文章编号: N24091712
期刊: Science of the Total Environment
作者: Songlin Liu, Hongxue Luo, Stacey M Trevathan-Tackett, Jiening Liang, Lifeng Wang, Xia Zhang, Yuzheng Ren, Zhijian Jiang, Yunchao Wu, Chunyu Zhao, Xiaoping Huang
更新时间: 2024-09-17
摘要: High coastal nutrient loading can cause changes in seagrass chemistry traits that may lead to variability in seagrass litter decomposition processes. Such changes in decomposition have the potential to alter the carbon (C) sequestration capacity within seagrass meadows (‘blue carbon’). However, the external and internal factors that drive the variability in decomposition rates of the different organic matter (OM) types of seagrass are poorly understood, especially recalcitrant OM (i.e. cellulose-associated OM and lignin-associated OM), thereby limiting our ability to evaluate the C sequestration potential. It was conducted a laboratory incubation to compare differences in the decomposition of litter collected from seagrass meadows with contrasting nutrient loading histories. The exponential decay constants of seagrass litter mass, cellulose-associated OM and lignin-associated OM were 0.009–0.032, 0.014–0.054 and 0.009–0.033 d, respectively. The seagrass litter collected from meadows with high nutrient loading exhibited greater losses of mass (25.0–41.2 %), cellulose-associated OM (2.8–18.5 %) and lignin-associated OM (9.6–31.2 %) than litter from relatively low nutrient loading meadows. The initial and temporal changes of the litter nitrogen (N) and phosphorus (P) concentrations, stoichiometric ratios of lignin/N, C/N, and C/P, and cellulose-associated OM content, were strongly correlated with the losses of litter mass and different types of OM. Further, temporal changes of litter C and OM types, particularly the OM and labile OM concentrations, were identified as the main driving factors for the loss of litter mass and loss of different OM types. These results indicated that nutrient-loaded seagrass litter, characterized by elevated nutrient levels and diminished amounts of recalcitrant OM, exhibits an accelerated decay rate for the recalcitrant OM. These differences in litter quality would lead to a reduced contribution of seagrass litter to long-term C stocks in eutrophic meadows, thereby weakening the stability of C sequestration. Considering the expected changes in seagrass litter chemistry traits and decay rates due to long-term nutrient loading, this study provides useful information for improving C sequestration capabilities through effective pollution management.

264. 题目: Going deep on marine lipid metabolism.
文章编号: N24091711
期刊: Science
作者: Florence Schubotz
更新时间: 2024-09-17
摘要: Marine algae account for almost half of global carbon fixation. A substantial proportion of this photosynthetic biomass is exported to the deep ocean through the biological carbon pump (see the figure). As algal biomass sinks through the water column, it is slowly degraded by diverse microorganisms (1). Ultimately, only a fraction reaches the seafloor, where it becomes buried over geologic timescales (2). Although studies have uncovered the microbial networks associated with sinking particle degradation (3), the processes that transform organic material as it descends remain poorly understood. On page 1182 of this issue, Behrendt et al. (4) report that cooperation between marine bacteria with distinct dietary preferences for lipid components of sinking organic matter can influence the transport efficiency of lipid carbon to the seabed. Understanding how microbial metabolism constrains the biological carbon pump is vital given its role as a regulator for atmospheric carbon dioxide (CO2) concentrations (2).

265. 题目: Simultaneously reducing methane emissions and arsenic mobility by birnessite in flooded paddy soil: Overlooked key role of organic polymerisation
文章编号: N24091710
期刊: Science of the Total Environment
作者: Weiwei Zhai, Ruihua Zhang, Xin Zhou, Yanyue Ma, Xiangbiao Zhang, Lijun Fan, Muhammad Zaffar Hashmi, Daoyong Zhang, Xiangliang Pan
更新时间: 2024-09-17
摘要: Flooding of paddy fields enhances methane (CH) emissions and arsenic (As) mobilisation, which are crucial issues for agricultural greenhouse gas emissions and food safety. Birnessite (δ-MnO) is a common natural oxidant and scavenger for heavy metals. In this study, birnessite was applied to As-contaminated paddy soil. The capacity for simultaneously alleviating CH emissions and As mobility was explored. Soil microcosm incubation results indicated that birnessite addition simultaneously reduced CH emissions by 47 %–54 % and As release by 38 %–85 %. The addition of birnessite decreased the dissolved organic carbon (DOC) contents and altered its chemical properties. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) results showed that birnessite reduced the labile fractions of proteins, carbohydrates, lignins, tannins, and unsaturated hydrocarbons, however, increased the abundance of condensed aromatic structures, suggesting the polymerisation of dissolved organic matter (DOM) by birnessite. The degradation of labile fractions and the polymerisation of DOM resulted in an inventory of recalcitrant DOM, which is difficult for microbes to metabolise, thus inhibiting methanogenesis. In contrast, birnessite addition increased CH oxidation, as the particulate methane monooxygenase () gene abundance increased by 30 %. The enhanced polymerisation of DOM by birnessite also increased As complexation with organics, leading to the transfer of As to the organic bound phase. In addition, the decrease in ferrous ion [Fe(II)] concentrations with birnessite indicated that the reductive dissolution of Fe oxides was suppressed, which limited the release of arsenite [As(III)] under reducing conditions. Furthermore, birnessite decreased As methylation and shaped the soil microbial community structure by enriching the metal-reducing bacterium . Overall, our results provide a promising method to suppress greenhouse gas emissions and the risk of As contamination in paddy soils, although further studies are needed to verify its efficacy and effectiveness under field conditions.

266. 题目: Nitrogen-sulfur co-doped magnetic biochar efficiently activates hydrogen peroxide for the degradation of sulfamethazine
文章编号: N24091709
期刊: Chemical Engineering Journal
作者: Linan Xu, Yifu Peng, Bin Zheng, Zhanqiang Fang
更新时间: 2024-09-17
摘要: To address the issue of low activation efficiency of magnetic biochar (MBC), this research synthesized nitrogen-sulfur co-doped magnetic biochar (NSMBC) using sawdust as the primary material via impregnation pyrolysis method. NSMBC effectively activated hydrogen peroxide and exhibited significant oxidation and degradation capabilities towards sulfamethazine (SMT), a sulfonamide antibiotic. The results demonstrate that under optimal conditions, NSMBC achieves a removal rate of 99.7 % for SMT within 2 h, with a reaction rate constant 8.5 times higher than that of MBC/HO system. Mechanistic investigations unveiled that hydroxyl radicals (·OH) were the primary agents responsible for the degradation of sulfamethazine within the NSMBC/HO system, contributing to 83.26 % of the removal efficiency. Furthermore, the nitrogen-sulfur co-doping facilitates the increase in Fe(II) content, augmentes the defect density, and enriches the number of oxygen-containing functional groups, thereby enhancing the utilization efficiency of HO and consequently boosting the activation performance of magnetic biochar. Notably, the NSMBC/HO system demonstrated excellent degradation efficiency towards various antibiotics, exhibiting potent broad-spectrum activity. Minimal influence on the NSMBC/HO system was observed under conditions of coexisting natural organic matter and anions, rendering it suitable for practical application in the treatment of aquaculture wastewater and providing a novel technology for the application of magnetic biochar in actual water pollution control scenarios.

267. 题目: Biochar coupled with multiple technologies for the removal of nitrogen and phosphorus from water: A review
文章编号: N24091708
期刊: Journal of Environmental Management
作者: Yaping Zhang, Bing Wang, Masud Hassan, Xueyang Zhang
更新时间: 2024-09-17
摘要: Water eutrophication caused by nitrogen (N) and phosphorus (P) has become a global environmental issue. Biochar is a competent adsorbent for removing N and P from wastewater. However, compared with commercial activated carbon, biochar has relatively limited adsorption capacity. To broaden the field scale application of biochar, biochar coupled with multiple technologies (BC-MTs) (such as microorganisms, electrochemistry, biofilm, phytoremediation, etc.) have been extensively developed for environmental remediation. Nevertheless, due to the fluctuations and differences in biochar types, coupling methods, and wastewater types, various techniques show different removal mechanisms and performance, hindering the promotion and application of BC-MTs. A systematic review of the research progress of BC-MTs is highly necessary to gain a better understanding of the current research status and progress, as well as to promote the application of these techniques. In this paper, the application of pristine and modified biochar in adsorbing N and P in wastewater is critically reviewed. Then the removal performance, influencing factors, mechanisms, and the environmental applications of BC-MTs in wastewater are systematically summarized. In addition, the cost analysis and risk assessment of BC-MTs in environmental applications are conducted. Finally, suggestions and prospects for future research and practical application are put forward.

268. 题目: Humic acid enhances the co-transport of colloids and phosphorus in saturated porous media
文章编号: N24091707
期刊: Chemosphere
作者: Changxi Wang, Simin Yao, Renkuan Liao, Jirka Šimůnek
更新时间: 2024-09-17
摘要: Phosphorus (P) has been widely recognized as a substance that is difficult to transport due to its tendency to become easily fixed in the soil. However, many reports demonstrate that groundwater P pollution is rising in humus-rich areas. Research is urgently needed to confirm (or reject) the hypothesis that increased P pollution is related to humus, as there is currently limited quantitative research on this topic. In this study, we conducted a series of batch equilibrium adsorption-desorption experiments and column experiments to quantify the effects of montmorillonite colloids (MCs) and humic acids (HCs, the main components of humus) on the P transport behavior. The results indicate that P's adsorption and desorption behavior on MCs can be well simulated using the Langmuir and Temkin models ( > 0.91). Compared to the non-HC treatments, HCs significantly increased MCs' P adsorption and desorption capacity 5.18 and 7.21 times, respectively. Moreover, HCs facilitated the transport ability of the MC-P mixture through the saturated quartz sand column. In a 0.1 M NaCl solution, the MC-P mixture is nearly completely adsorbed on the surface of quartz sand, with a penetration rate of only 0.5%. In contrast, the HC-MC-P mixture can evidently penetrate further at a rate of 26.1%. The transport parameters fitted using HYDRUS-1D further indicated that the presence of humic acids significantly decreased the deposition coefficients of colloids, thereby enhancing the co-transport of colloids and P through the quartz sand porous medium. The potential mechanism of P pollution in humus-rich areas is likely enhanced by the formation of an HC-colloid-P mixture, which greatly increases the adsorption amount of P on colloids and enhances the electrostatic and spatial repulsion between colloids as well as between colloids and quartz sand. It reduces the aggregation and adsorption of colloids, ultimately transferring P into groundwater through colloid-facilitated co-transport. The findings of this study clarified the relationship between the transport of P, colloids, and HCs, which provides a theoretical basis for explaining the P pollution mechanism in humus-rich areas.

269. 题目: Divergent response of upper layer soil organic and inorganic carbon to biotic and abiotic factors in afforestation by aerial seeding in desert, China
文章编号: N24091706
期刊: Catena
作者: Tengfei Yu, Qi Feng, Yidan Yin, Tuo Han, Weiyu Chen, Meng Zhu, Chenguang Zhao, Jing Zhao
更新时间: 2024-09-17
摘要: In arid lands, soil inorganic carbon (SIC) is as important as soil organic carbon (SOC), and both of was governing by climate, vegetation, soil properties and human activities. However, there has been limited focus on the relative importance of abiotic and biotic factors in governing content of SOC and SIC in desert. To address this gap, we determine the variations of upper layer (0–20 cm) SOC and SIC content and their controlling factors following the nearly 40 years afforestation by aerial seeding in the edge of the Tengger Desert, China. The results showed that upper layer SIC was rapidly increased in the first 10 years and subsequently stabilized at 2.0 g kg, when it was about twice of SOC. The correlation and random forest analysis indicated that soil physicochemical properties, including clay and silt content, calcium, available kalium, electrical conductivity, total nitrogen and phosphorus, have higher correlation with SOC than the other properties. In contrast, calcium and bacterial richness indexes (ACE and Chao1) were found to be crucial in determining the variation of SIC. Similarly, the structural equation model and variance partitioning analysis illustrated that soil physicochemical properties and microbial diversity have different effects on SOC and SIC. Furthermore, the linear mixed-effects model determined that soil physicochemical properties and microbial diversity have relative effects of 70.38 % and 29.62 % on variation of SOC, and of 19.91 % and 80.09 % on variation of SIC, respectively. In conclusion, our study demonstrates the divergent response of SOC and SIC to biotic and abiotic factors, and underscores the significance of bacterial richness in determining SIC in desert with enriched calcium and alkali. Our findings provide an improved understanding between soil carbon and biotic factors after plantation in desert.

270. 题目: Transport and retention mechanisms of highly suspended biochar in aquifer media
文章编号: N24091705
期刊: Bioresource Technology
作者: Chongkai Zhao, Xueyu Lin, Xiaosi Su, Jinlong Qian, Shengyu Zhang
更新时间: 2024-09-17
摘要: Biochar-based in-situ reaction zones are promising methods for groundwater remediation. However, the transport and retention of biochar in aquifer media remain unclear. Herein, biochar with high suspensibility was developed through nitrogen doping. A linear regression was used to analyze the relationship between particle size, concentration, time, and suspension rate. Seepage column experiments were conducted to investigate the transport and retention mechanisms of biochar in the aquifer medium. The ratio of biochar particle size (d) to medium particle size (D) affected the permeability coefficient. At a 3.0 g/L injected concentration, hydraulic conductivity decreased within 3.3 × 10 ≤ d/D ≤ 8.4 × 10. Within 9.7 × 10 ≤ d/D ≤ 1.9 × 10, hydraulic conductivity first increased and then decreased. Within 2.5 × 10 ≤ d/D ≤ 5.7 × 10, hydraulic conductivity slightly increased and then stabilized. This study confirms that nitrogen-doped biochar is an excellent remediation material for in-situ reaction zone.

271. 题目: Organic matter the major sink of redox-sensitive trace elements in Upper Devonian black shale
文章编号: N24091704
期刊: Chemical Geology
作者: Omid H Ardakani, Michael G Gadd, Makram Hedhli, Duane Petts, Gavin Jensen
更新时间: 2024-09-17
摘要: The Bakken Formation is a hydrocarbon-rich, metalliferous shale with subordinate sandstone and limestone that was deposited in the Williston Basin in Canada and the USA. Deposition of the Bakken Formation spanned the Devonian-Carboniferous boundary – a key interval in Earth's history representing profound biotic and geochemical changes in the terrestrial and marine realms, leading to deposition of metal-rich shales in the lower part of the sequence. Most studies of metal enrichment in the Bakken Formation have focused solely on the bulk rock litho-geochemistry, with little attention given to the organic matter, mineralogical, and diagenetic controls on metal sequestration and distribution.

272. 题目: Improved humification and Cr(VI) immobilization by CaO2 and Fe3O4 during composting
文章编号: N24091703
期刊: Bioresource Technology
作者: Li Chen, Zhigang Yi, Yaoning Chen, Yuanping Li, Hongjuan Jiang, Jun Wang, Yanrong Chen, Yaoqin Nie, Mengwei Luo, Qianruyu Wang, Wei Zhang, Yanting Wu
更新时间: 2024-09-17
摘要: The current research studied how FeO nanomaterials (NMs) and CaO affect humification and Cr(VI) immobilization and reduction during the composting of oil-tea Camellia meal and Cr-contaminated soil. The results showed that FeO NMs and CaO successfully construct a Fenton-like reaction in this system. The excitation-emission matrix-parallel factor (EEM-PARAFAC) demonstrated that this Fenton-like treatment increased the generation of humic acids and accelerated the humification. Meantime, RES-Cr increased by 5.91 % and Cr(VI) decreased by 16.36 % in the treatment group with CaO and FeO NMs after 60 days. Moreover, the microbial results showed that FeO NMs and CaO could promote the enrichment of Cr(VI) reducing bacteria, e.g., , , and , and promote Cr(VI) reduction. This study gives a novel view and theoretical reference to remediate Cr(VI) pollution through composting.

273. 题目: Sources and transport of organic matter in the Ganges-Brahmaputra-Meghna River system of Bengal Basin, Bangladesh
文章编号: N24091702
期刊: Marine Pollution Bulletin
作者: Md Hafijur Rahaman Khan, Jianguo Liu, Ananna Rahman, Yun Huang, Long Tan, Shengfa Liu, Zhong Chen
更新时间: 2024-09-17
摘要: This study aimed to understand the sources and transport mechanism of organic matter (OM) in the Ganges-Brahmaputra-Meghna (GBM) river system in Bangladesh. We conducted analyses of total organic carbon (TOC), total nitrogen (TN), their stable isotopes (δC and δN), and sediment grain size. The results reveal a heterogeneous mixture of OM derived from terrestrial plants, aquatic environments, and anthropogenic sources. The Brahmaputra River exhibited higher concentrations of TOC and TN, with δC and δN values indicating that the OM is primarily sourced from C plants. Conversely, the Ganges River demonstrated lower TOC levels and higher isotopic values, reflecting significant anthropogenic inputs. The Lower Meghna showed a mixture of terrestrial and marine sources. Variations in the TOC/TN ratios across the river system underscore the complex interplay between natural and anthropogenic factors. Additionally, sediment grain size plays a crucial role, with finer sediments in the Brahmaputra River associated with increased OM concentrations, while coarser sediments in the Ganges River correlate with lower TOC and TN levels.

274. 题目: Effects of exogenously added humic acid on the fate of aminoglycoside antibiotics and humification process during aerobic compost
文章编号: N24091701
期刊: Chemical Engineering Journal
作者: Guoxu Ao, Zhaoxuan Wang, Yueqi Shi, Hongzhi Ling, Shanshan Sun, Wenxiang Ping
更新时间: 2024-09-17
摘要: Efficient elimination of antibiotics, particularly aminoglycosides, and Antibiotic resistance genes (ARGs) from agricultural and livestock waste, as well as enhancing the level of humification, remains a major challenge in the pursuit of high-value utilization of agricultural waste. Here, the roles of bacteria and fungus in the dissipation of aminoglycoside antibiotics, ARGs and the enhancement of humification with the addition of humic acid (HA) to compost systems were investigated. Compared to the control, the contents of humus (HS) and HA were increased by 41.3 and 143.3 %, respectively, and the content of fulvic acid (FA) was decreased by 74.1 % with HA addition. Interestingly, the abundance of aminoglycoside ARGs was decreased significantly ( < 0.05) as well as the abundance of functional genes involved in oxidative stress response and type IV secretion system (T4SS). The bacterium related to carbon cycle, and the fungi Ascomycota and Basidiomycota associated with ligocellulose degradation were significantly enriched ( < 0.05). Structural equation models revealed that the decrease in aminoglycoside ARGs abundance was attributed to bacteria promoting HA synthesis, thereby inhibiting the multiplication of aminoglycoside ARGs and ultimately mitigating oxidative damage to microbial cells. These findings shed light on the mechanism by which HA removes aminoglycoside ARGs, and provide valuable insights into enhancing the biosafety of compost products.

275. 题目: Eutrophication constrains driving forces of dissolved organic carbon biodegradation in metropolitan lake systems
文章编号: N24091418
期刊: Science of the Total Environment
作者: Xiaokang Tian, Menglin Liu, Zhengtong Li, Xinyu Gao, Ruoxi Yang, Maofei Ni, Y Jun Xu, Yang Wang, Chen Ye, Danni Yuan, Siyue Li
更新时间: 2024-09-14
摘要: Dissolved organic carbon (DOC) components can be highly variable in aquatic ecosystems, and play a pivotal role in the global carbon cycles. To comprehend potential effects of nutrient enrichment on portion of DOC biodegradability (%BDOC), we conducted an extensive investigation on 26 urban lakes in a major metropolitan area in subtropical China in a small gradient of trophic levels from mesotrophic to light and middle eutrophic. In addition to field measurements on lake ambient conditions and laboratory analysis of DOC characteristics, we conducted a 28-day temperature-controlled incubation experiment, in which %BDOC of lake waters was determined. In the mesotrophic waters, %BDOC ranged from 0.6 to 41.4 % (11.2 ± 8.9 %). The %BDOC levels spanned from 5.2 to 20.2 % (10.7 ± 4.0 %) in the light eutrophic waters, and the %BDOC ranged from 2.7 to 35.0 % (13.7 ± 8.4 %) in the middle eutrophic waters. We found a significant change in DOC chemical composition across the study lakes characterized by shifting of trophic levels. Although the experiment found significant changes in the factors that can influence %BDOC, a significant difference was not observed in %BDOC among the three trophic levels. The %BDOC was primarily influenced by the inherent DOC concentration and aromaticity, with eutrophication leading to the varied driving factors of %BDOC in lake systems. We show that most of the lake water DOC was stable. The findings indicate the intricate interplay between biological metabolism and nutrient availability governing %BDOC dynamics in urban lake ecosystems.

276. 题目: Immediate and prolonged effects of snow coverage alteration on soil carbon dynamics and microbial activity: A meta-analysis
文章编号: N24091417
期刊: Geoderma
作者: Jia Hua, Qiaoqi Sun, Petra Marschner
更新时间: 2024-09-14
摘要: Snow distribution has been altered over the past decades under global warming, with a significant reduction in duration and extent of snow cover and an increase in unprecedented snowstorms across large areas in cold regions. The altered snow conditions are likely to have immediate (in winter) and carry-over or legacy (which an extended effect might continue in the following spring, summer and autumn) impacts on soil processes and functioning, but a quantification of the legacy effect of snow coverage alternation is still lacking. Furthermore, studies investigating the effect of snow cover changes on soil respiration, soil carbon pools and microbial activity are increasing, but contrasting results of different studies makes it difficult to assess the overall effect of snow cover changes and the underlying mechanisms, thus a systematic and comprehensive -analysis is required. In this study, we synthesized the results from 60 papers based on field snow manipulation experiments and conducted a -analysis to evaluate immediate and prolonged effects on eight variables related to soil carbon dynamics and microbial activity to snow coverage alternation. Results showed that snow removal had no significant effect on soil respiration, but increased dissolved organic carbon (DOC) (11.5%) and fungal abundance (32.0%). By contrast, snow addition significantly increased soil respiration (16.3%) and microbial biomass carbon (MBC) (6.6%). Snow addition had immediate and prolonged impacts on soil carbon dynamics and microbial activity lasting from winter to the following autumn, whereas an effect of snow removal on total organic carbon (TOC) and DOC was detectable only in the following spring. Snow depth, ecosystem and soil types determined the extent of the impact of snow treatments on soil respiration, DOC, MBC and microbial biomass nitrogen (MBN). Our findings provide critical insights into understanding how changes in snow coverage affect soil respiration and microbial activity. We suggest future field-based experiments to enhance our understanding the effect of climate change on soil processes and functioning in the winter and the following seasons.

277. 题目: Emerging multiscale insights on microbial carbon use efficiency in the land carbon cycle
文章编号: N24091416
期刊: Nature Communications
作者: Xianjin He, Elsa Abs, Steven D Allison, Feng Tao, Yuanyuan Huang, Stefano Manzoni, Rose Abramoff, Elisa Bruni, Simon P K Bowring, Arjun Chakrawal, Philippe Ciais, Lars Elsgaard, Pierre Friedlingstein, Katerina Georgiou, Gustaf Hugelius, Lasse Busk Holm, Wei Li, Yiqi Luo, Gaëlle Marmasse, Naoise Nunan, Chunjing Qiu, Stephen Sitch, Ying-Ping Wang, Daniel S Goll
更新时间: 2024-09-14
摘要:

Microbial carbon use efficiency (CUE) affects the fate and storage of carbon in terrestrial ecosystems, but its global importance remains uncertain. Accurately modeling and predicting CUE on a global scale is challenging due to inconsistencies in measurement techniques and the complex interactions of climatic, edaphic, and biological factors across scales. The link between microbial CUE and soil organic carbon relies on the stabilization of microbial necromass within soil aggregates or its association with minerals, necessitating an integration of microbial and stabilization processes in modeling approaches. In this perspective, we propose a comprehensive framework that integrates diverse data sources, ranging from genomic information to traditional soil carbon assessments, to refine carbon cycle models by incorporating variations in CUE, thereby enhancing our understanding of the microbial contribution to carbon cycling.

278. 题目: Synchronous reinforcement azo dyes decolorization and anaerobic granular sludge stability by Fe, N co-modified biochar: enhancement based on extracellular electron transfer
文章编号: N24091415
期刊: Journal of Hazardous Materials
作者: Longyi Lv, Bingbing Yin, Duoying Zhang, Wenbo Ji, Jinsong Liang, Xiaoyang Liu, Wenfang Gao, Li Sun, Zhijun Ren, Guangming Zhang, Ruijun Zhang
更新时间: 2024-09-14
摘要:

Anaerobic digestion (AD) treatment of azo dyes wastewater often suffers from low decolorization efficiency and poor stability of anaerobic granular sludge (AnGS). In this study, iron and nitrogen co-modified biochar (FNC) was synthesized based on the secondary calcination method, and the feasibility of this material for enhanced AD treatment of azo dye wastewater and its mechanism were investigated. FNC not only formed richer conducting functional groups, but also generated Fe²⁺/Fe³⁺ redox pairs. The decolorization efficiency of Congo red and AD properties (e.g., methane production) were enhanced by FNC. After adding FNC, the content of extracellular polymeric substances (EPS) and the ratio of proteins remained stable under the impact of Congo red, which greatly protected the internal microbial community. This was mainly contributed to the excellent electrochemical properties of FNC, which strengthened the microbial extracellular electron transfer and realized the coupled mechanism of action: On the one hand, an electron transfer bridge between decolorizing bacteria and dyes was constructed to achieve rapid decolorization of azo dyes and mitigate the impact on methanogenic bacteria; On the other hand, the stability of AnGS was enhanced based on enhanced extracellular polymeric substances secretion, microbial community and direct interspecies electron transfer (DIET) process. This study provides a new idea for enhanced AD treatment of azo dyes wastewater.

279. 题目: Sequential carbonization of pig manure biogas residue into engineered biochar for diethyl phthalate removal toward environmental sustainability
文章编号: N24091414
期刊: Waste Management
作者: Min Wang, Xiangzhou Yuan, Changyin Zhu, Haiying Lu, Jiangang Han, Rongting Ji, Hu Cheng, Jianming Xue, Dongmei Zhou
更新时间: 2024-09-14
摘要: Manure biogas residue has attracted increasing attention in waste recycling but faces substantial challenges because of its low carbon content, high ash content, and high heavy metal content. A novel sequential carbonization approach was proposed for recycling biogas residue; this approach consisted of pre-pyrolysis, activation with Ca(OH), and then activation with KOH. Pig manure-derived biogas residue was upcycled into engineered biochar (EB) with a high yield (26 %) and showed excellent performance in removing a typical plasticizer, diethyl phthalate (DEP). The proportion of carbon content greatly increased from 18 % (biogas residue) to 67 % (EB); however, the ash content decreased from 50 % (biogas residue) to 24 % (EB). The concentration of heavy metals decreased, and Zn had the largest decrease from 713 mg kg to 61 mg kg ( < 0.001). The sorption of DEP onto EB was rapid and reached equilibrium within 20 h. The developed specific surface area of EB was 1247 m/g and provided abundant sorption sites for DEP; additionally, the sorption quantity reached 309 mg/g. The sorption capacity was dominated by surface adsorption. The oxygen-containing functional groups, graphene structure, porous structure, and hydrophobicity of EB contributed to the pore filling, hydrogen bonding, π–π stacking, and partitioning processes. Furthermore, the EB showed excellent practical application potential and great cycling stability. A sequential carbonization strategy was proposed to upcycle manure biogas residue into the EB for DEP removal; moreover, this strategy can aid in the attainment of environmental sustainability, including sustainable waste management and environmental pollution mitigation.

280. 题目: Recovery of Phosphate From Aqueous Solution by Mg/Ca-Modified Biochar Derived From Dewatered Dry Sludge and Waste Almond Shells and Its Potential Application
文章编号: N24091413
期刊: Water, Air, & Soil Pollution
作者: Dong Yang, Jia-li Cui, Chao-neng Ning, Feng Zhang, Jing-yi Gao
更新时间: 2024-09-14
摘要:

Phosphorus is an essential element of ecosystems, supporting the growth of plants and animals; however, its excessive presence in water can lead to eutrophication. In this study, the phosphate adsorbent SA2:8 Mg/Ca was prepared by loading calcium and magnesium onto sludge and almond shell. Various characterization methods were used to analyze biochar, and the phosphorus removal effect of SA2:8 Mg/Ca under different conditions was evaluated. The results showed that the phosphate removal rate of the adsorbent was more than 70% in the range of pH 4 ~ 12, and the adsorption performance was significantly affected by HCO₃⁻ and SO₄²⁻, though the removal rate remained over 50%. The adsorption process conforms to the pseudo-second-order model, and the isothermal adsorption model aligns more closely with the Langmuir model. Increased temperature was favorable for phosphate adsorption. The theoretical maximum adsorption capacity of SA2:8 Mg/Ca was 78.27 mg/g. Thermodynamic analysis confirmed that the adsorption process was spontaneous. The main mechanisms of adsorption include electrostatic interaction, ion exchange, Lewis acid–base interaction, and chemical precipitation. Additionally, the P-laden biochar exhibited excellent potential for application: it can be used as a catalyst to improve the efficiency of persulfate catalytic degradation of ofloxacin. The removal rate of OFX in water by the SA2:8 Mg/Ca-PS system was 81.4%.

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