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41. 题目: Impact of fire exclusion and aspect on soil carbon fractions in Afromontane grasslands, Cathedral Peak, South Africa
文章编号: N24071211
期刊: European Journal of Soil Science
作者: Lindokuhle X Dlamini, Elmarie Kotzé, Mathieu Thevenot, Gregor T Feig, Olivier Mathieu, Jean Lévêque
更新时间: 2024-07-12
摘要: Despite the importance of South Africa's Afromontane grasslands for ecosystem services (water supply and biodiversity), soil organic carbon (SOC) research remains limited. These grasslands evolved with fire, and fire exclusion leads to native plant afforestation. This study investigated SOC fractions and origin to understand the impact of fire‐exclusion‐driven afforestation and aspect on SOC storage in Afromontane grasslands. This study in Cathedral Peak Research Catchments, initiated in the 1940s, compared an afforested fire‐excluded site (AF) to a periodically burnt (accidental fires, 2–5 years interval) grassland (PB) within the same catchment (Catchment‐IX). Additionally, it compared a south‐facing periodically burnt grassland (Catchment‐IX) to a north‐facing biennially burnt grassland (Catchment‐VI). Soil samples collected at soil‐depth increments (0–5, 5–10, 10–15, 15–20, 20–30, 30–60 and 60–100 cm) revealed that, within Catchment IX, PB had more topsoil SOC stocks and microbial activity than AF but similar active carbon (C) concentrations. As expected, δ13C values revealed that SOC in PB originates from C4 grasses, whilst it mostly originates from C3 plants in AF. The south‐facing slope (Catchment‐IX) had more SOC stocks, microbial activity and active C compared to the north‐facing slope (Catchment‐VI). Fire‐exclusion‐driven afforestation changed SOC input from roots to litter, thus reducing SOC storage. Cooler south‐facing slopes are better C reservoirs. Afromontane grasslands show greater potential for C sequestration than afforested systems.

42. 题目: Aquatic processing enhances the loss of aged carbon from drained and burned peatlands
文章编号: N24071210
期刊: Global Change Biology
作者: Jennifer C Bowen, Alison M Hoyt, Xiaomei Xu, Muhammad Nuriman, Gusti Z Anshari, Putri Juliandini Wahyudio, Lihini I Aluwihare
更新时间: 2024-07-12
摘要: Water-logged peatlands store tremendous amounts of soil carbon (C) globally, accumulating C over millennia. As peatlands become disturbed by human activity, these long-term C stores are getting destabilized and ultimately released as greenhouse gases that may exacerbate climate change. Oxidation of the dissolved organic carbon (DOC) mobilized from disturbed soils to streams and canals may be one avenue for the transfer of previously stored, millennia-aged C to the atmosphere. However, it remains unknown whether aged peat-derived DOC undergoes oxidation to carbon dioxide (CO2) following disturbance. Here, we use a new approach to measure the radiocarbon content of CO2 produced from the oxidation of DOC in canals overlying peatland soils that have undergone widespread disturbance in Indonesia. This work shows for the first time that aged DOC mobilized from drained and burned peatland soils is susceptible to oxidation by both microbial respiration and photomineralization over aquatic travel times for DOC. The bulk radiocarbon age of CO2 produced during canal oxidation ranged from modern to ~1300 years before present. These ages for CO2 were most strongly influenced by canal water depth, which was proportional to the water table level where DOC is mobilized from disturbed soils to canals. Canal microbes preferentially respired older or younger organic C pools to CO2, and this may have been facilitated by the use of a small particulate organic C pool over the dissolved pool. Given that high densities of canals are generally associated with lower water tables and higher fire risk, our findings suggest that peatland areas with high canal density may be a hotspot for the loss of aged C on the landscape. Taken together, the results of this study show how and why aquatic processing of organic C on the landscape can enhance the transfer of long-term peat C stores to the atmosphere following disturbance.

43. 题目: Soil carbon management and enhanced rock weathering: The separate fates of organic and inorganic carbon
文章编号: N24071209
期刊: European Journal of Soil Science
作者: David A C Manning, Antonio Carlos de Azevedo, Caio F Zani, Arlete S Barneze
更新时间: 2024-07-12
摘要: Soil carbon (C) management has been promoted as one of the few readily available strategies to mitigate the rising concentration of atmospheric CO2 and its associated impacts on climate change. One of these carbon management strategies is enhanced rock weathering (ERW) which involves adding crushed silicate rocks to the soil. These rocks weather and remove atmospheric CO2 by converting it into bicarbonate in solution. The approach requires careful interpretation of the differences between soil organic carbon (SOC) and soil inorganic carbon (SIC) and their measurement, with implications for land management and C credit accounting. In this Opinion, we emphasise the distinct nature and fates of SOC and SIC, advocating for their separate management, particularly in C credit schemes. It is imperative that protocols for soil C management explicitly recognise the difference between SOC and SIC to prevent any ambiguity. Farmers should be able to claim credits for increases in SOC alongside and independently of any claim for credits for ERW (i.e. SIC). Despite the potential of ERW for C removal, we emphasise that further research is needed to improve the measurement and monitoring of SIC and to understand ERW's potential implications for SOC turnover and greenhouse gas emissions.Highlights Enhanced Rock Weathering increases dissolved inorganic carbon (bicarbonate). Soil organic carbon (SOC) may be influenced by Enhanced Rock Weathering. Carbon credit via Enhanced Rock Weathering is separate from credit linked to soil organic carbon. Soil organic matter and enhanced rock weathering both have roles to play for carbon credits.

44. 题目: Abrupt shift in the organic matter input to sediments in Lake Liangzi, a typical macrophyte-dominated shallow lake in Eastern China, and its response to anthropogenic impacts
文章编号: N24071208
期刊: Science of the Total Environment
作者: Yongdong Zhang, Ning Liu, Weizhen Lei, Huan Fu, Zhengwen Liu
更新时间: 2024-07-12
摘要: Understanding the historical variations in organic matter (OM) input to lake sediments and the possible mechanisms regulating this phenomenon is important for studying carbon cycling and burial in lake systems; however, this topic remains poorly addressed for macrophyte-dominated lakes. To bridge these gaps, we analyzed bulk OM and molecular geochemical proxies in a dated sediment core from Lake Liangzi, a typical submerged macrophyte-dominated lake in East China, to infer changes in OM input to sediments over the past 169 years due to the intensification of human activities in the catchment. A relatively primitive OM input pattern was observed in ca. 1841–1965, during which the lowest hydrogen index (HI), short-chain -alkane abundance, and -C/-C alkane indicated minimal input from phytoplankton, whereas the high Paq (proxy of aquatic macrophyte input) and long-chain -alkane abundance suggested dominant and subordinate inputs from submerged and emergent macrophytes, respectively. OM input transitioned during ca. 1965–1993, with the highest Paq and lowest long-chain -alkane abundance, indicating an increase of submerged macrophyte input and concurrent decline of emergent macrophyte input, probably caused by hydrological regulation practices and land reclamation in the 1960s, respectively. A further shift in OM input was observed since ca. 1993, characterized by the beginning of an increase in phytoplankton input, as indicated by the greater HI, short-chain -alkane abundance, and -C/-C alkane in sediments. Moreover, a lower Paq and higher abundance of long-chain -alkanes indicated a decline in input from submerged macrophytes and an elevated input from terrestrial plants. The increase in αβ-hopane abundance and homohopane index value indicated that petroleum-sourced OM was first introduced into the sediments. The causes of these OM input changes included nutrient influx associated with domestic and industrial discharge, aquaculture within the lake, and widespread deforestation and land clearance in the catchment.

45. 题目: Lipid biomarkers and stable isotopes uncover paleovegetation changes in extremely species-rich forest-steppe ecosystems, Central Europe
文章编号: N24071207
期刊: Environmental Research
作者: Mohammad Tahsin Karimi Nezhad, Pavel Šamonil, Pavel Daněk, Jakub Jaroš, Michal Hájek, Petra Hájková, Stanislav Jabinski, Travis.B. Meador, Jan Roleček
更新时间: 2024-07-12
摘要: The historical development of the vegetation of semi-dry grasslands in Central Europe is not satisfactorily understood. Long-term continuity of open vegetation or, conversely, deep-past forest phases are considered possible sources of the current extreme species diversity of these ecosystems. We aimed to reveal the trajectory of paleovegetation development in these ecosystems through detailed analysis of terrestrial soil geoarchives. We measured the bulk soil carbon and nitrogen contents, lipid molecular distribution, and compound-specific stable carbon and hydrogen isotopic signatures of mid- and long-chain -alkanes extracted from soil and modern plant material tissues (i.e., deciduous and leaves and grass/herbaceous species).

46. 题目: Impact of low molecular weight organic acids on heavy metal(loid) desorption in biochar-amended paddy soil
文章编号: N24071206
期刊: Environmental Geochemistry and Health
作者: Qiuxiang Huang, Wenzhe Chen, Jinyan Gao, Fande Meng, Yongbing Cai, Yan Wang, Guodong Yuan
更新时间: 2024-07-12
摘要:

Low molecular weight organic acids (LMWOAs) are important soil components and play a key role in regulating the geochemical behavior of heavy metal(loid)s. Biochar (BC) is a commonly used amendment that could change LMWOAs in soil. Here, four LMWOAs of oxalic acid (OA), tartaric acid (TA), malic acid (MA), and citric acid (CA) were evaluated for their roles in changing Cd and SB desorption behavior in contaminated soil with (S1-BC) or without BC (S1) produced from Paulownia biowaste. The results showed that OA, TA, MA, and CA reduced soil pH with rising concentrations, and biochar partially offset the pH reduction by LMWOAs. The LMWOAs reduced Cd desorption from the soil at low concentrations but increased Cd desorption at high concentrations, and CA was the most powerful in this regard. The LMWOAs had a similar effect on Sb desorption, and CA was the most effective species of LMWOAs. Adding BC to the soil affects Cd and Sb dynamics by reducing the Cd desorption but increasing Sb desorption from the soil and increasing the distribution coefficient (Kd) values of Cd but lowering the Kd values of Sb. This study helped understand the effects of LMWOAs on the geochemical behavior of Cd and Sb in the presence of biochar, as well as the potential risks of biochar amendment in enhancing Sb desorption from contaminated soil.

47. 题目: Metagenomic insights into microbial variation and carbon cycling function in crop rotation systems
文章编号: N24071205
期刊: Science of the Total Environment
作者: Yinglei Zhang, Jinping Chen, Mingxue Du, Yihao Ruan, Yongchao Wang, Jiameng Guo, Qinghua Yang, Ruixin Shao, Hao Wang
更新时间: 2024-07-12
摘要: The decomposition and utilization of plant-derived carbon by microorganisms and carbon fixation are crucial pathways for enhancing soil organic carbon (SOC) storage. However, a gap remains in our understanding of the impact of microorganisms on the decomposition of plant-derived carbon and their capacity for carbon fixation in crop rotation systems. Based on a 12-year experiment with wheat–maize (WM), wheat–cotton (WC), and wheat–soybean (WS) rotations, the microbial communities and carbon cycle function were investigated. The results indicated that WS rotation significantly increased SOC content compared to WM and WC. In addition, a significant increase was observed in microbially available carbon and microbial biomass carbon in the WS soil compared with those in the others. Further analysis of the microbial community factors that influenced SOC content revealed that WS rotation, in contrast to WM rotation, enhanced the diversity and richness of bacteria and fungi. Analysis of microbial carbon decomposition functions revealed an increase in starch, lignin, and hemicellulose decomposition genes in the WS soil compared to the others. The changes in carbon decomposition genes were primarily attributed to six bacterial genera, namely , , , , , and , as well as four fungal genera, namely , , , and , which were significantly influenced by the crop rotation systems. In addition, microbial carbon fixation-related genes such as , , , , and were significantly enriched in WS. Species annotation of differential carbon fixation genes identified 18 genera that play a role in soil carbon fixation variation within the crop rotation systems. This study highlights the impact of crop rotation systems on SOC content and alterations in specific microbial communities on carbon cycle function.

48. 题目: The molecular binding sequence transformation of soil organic matter and biochar dissolved black carbon antagonizes the transport of 2,4,6-trichlorophenol
文章编号: N24071204
期刊: Science of the Total Environment
作者: Jin Zhang, Zhikang Zhou, Lingjun Zeng, Chen Wang, Ruixia Han, Xinlei Ren, Wenbing Wang, Minghui Xiang, Shuai Chen, Hui Li
更新时间: 2024-07-12
摘要: Dissolved organic matter (DOM) and dissolved black carbon (DBC) are significant environmental factors that influence the transport of organic pollutants. However, the mechanisms by which their molecular diversity affects pollutant transport remain unclear. This study elucidates the molecular binding sequence and adsorption sites through which DOM/DBC compounds antagonize the transport of 2,4,6-trichlorophenol (TCP) using column experiments and modelling. DBC exhibits a high TCP adsorption rate ( = 5.32 × 10 mol∙L∙min) and conditional stability constant ( = 5.19–5.74), indicating a strong binding affinity and antagonistic effect on TCP. This is attributed to the high relative content of lipid/protein compounds in DBC (25.65 % and 30.28 %, respectively). Moreover, the small molecule lipid compounds showed stronger TCP adsorption energy (E = −0.0071 eV/−0.0093 eV) in DOM/DBC, combined with two-dimensional correlation spectroscopy model found that DOM/DBC antagonized TCP transport in the environment through binding sequences that transformed from lipid/protein small molecule compounds to lignin/tannin compounds. This study used a multifaceted approach to comprehensively assess the impact of DOM/DBC on TCP transport. It reveals that the molecular diversity of DOM/DBC is a critical factor affecting pollutant transport, providing important insights into the environmental trend and ecological effects of pollutants.

49. 题目: Chitosan-sunflower meal biochar hydrogel incorporated with green synthesized NiO nanoparticles for enhanced catalytic reduction of anthropogenic water pollutants
文章编号: N24071203
期刊: Environmental Science and Pollution Research
作者: Abhipsa Mahapatra, Pravin Kumar Kar, Subhraseema Das
更新时间: 2024-07-12
摘要:

Anthropogenic activities have been one of the crucial driving factors for water pollution globally, thereby warranting a sustainable strategy for its redressal. In this study, we have developed a hydrogel-biochar nanocomposite for catalytic reduction of water pollutants. To begin with, green synthesis of nickel oxide nanoparticles (NiO NPs) was accomplished from waste kinnow peel extract via the environmentally benign microwave method. The formation of NiO NPs was affirmed from different analytical techniques namely ultraviolet-visible (UV-Vis), Fourier transform infrared (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and energy-dispersive spectroscopy (EDS). The FESEM images revealed spherical nature of NiO NPs. The average particle size was found to be 15.61 nm from XRD data. A novel hydrogel-biochar nanocomposite comprising the green NiO NPs, sunflower meal biochar and chitosan was prepared (Cs-biochar@ NiO) and explored as a nanocatalyst towards catalytic reduction of pollutants such as 4-nitrophenol, potassium hexacyanoferrate (III) and organic dyes methyl orange (MO), Congo red (CR), methylene blue (MB) in the presence of a reducing agent, i.e. NaBH4. Under optimized conditions, the reduction reactions were completed by 120 s and 60 s for 4-NP and potassium hexacyanoferrate (III) respectively and the rate constants were estimated to be 0.044 s–1 and 0.110 s–1. The rate of reduction was found to be faster for the dyes and the respective rate constants were 0.213 s–1 for MO, 0.213 s–1 for CR and 0.135 s–1 for MB. The assessment of the nanocatalyst in the reduction of binary dye systems depicted its selectivity towards the anionic dyes CR and MO. The nanocatalyst displayed effective reduction of dyes in real-water samples collected from different sources. Taken altogether, this study validates the design of sustainable hydrogel-biochar nanocatalyst for the efficient reduction of hazardous anthropogenic water pollutants.

Graphical

50. 题目: Decoupling of carbon burial from productivity in the northeast Indian Ocean
文章编号: N24071202
期刊: Science of the Total Environment
作者: Rajeev Saraswat, Rinu Fathima, Mohd Salman, Thejasino Suokhrie, S M Saalim
更新时间: 2024-07-12
摘要: The concentration of atmospheric carbon dioxide (CO) is a crucial climate parameter as it has far-reaching implications on global temperature. The oceans are a significant sink for CO. Biologically mediated carbon sequestration, in the form of both inorganic (CaCO) and organic carbon (C), and its subsequent burial in marine sediments play a vital role in regulating atmospheric CO. Understanding the distribution of carbon in marine sediments under different environments can help predict the fate of excess CO in the future. We studied the factors affecting the basin scale variation in carbon burial in the climatically sensitive northeast Indian Ocean, by using the data [CaCO, C, C/Nitrogen, and isotopic ratio (δC, δN) of organic carbon] from a total of 718 surface sediments. The entire continental shelf and slope contain <10 % CaCO. The highest CaCO is in the deepest parts of the central northeast Indian Ocean, away from the mouth of major river systems. Despite of the high productivity, the low C on the continental shelf is attributed to the well-oxygenated coarse-grained sediments. The lowest C is found in the well-oxygenated deeper central northeast Indian Ocean. Interestingly, the highest total carbon is in the deeper central and equatorial regions, far away from the highly productive marginal marine regions. Our study reveals that the grain size, terrigenous dilution, dissolved oxygen, and water masses strongly influence carbon accumulation in the northeast Indian Ocean, with only secondary influence of the productivity.

51. 题目: Preparation of biomass-derived porous biochar for efficient removal of iodized X-ray contrast media in water: Adsorption performance and underlying mechanism
文章编号: N24071201
期刊: Separation and Purification Technology
作者: Qiang Tan, Zhonglin Chen, Jimin Shen, Pengwei Yan, Jing Kang, Binyuan Wang, Yizhen Cheng, Shengxin Zhao, Yang Shen, Yabin Li
更新时间: 2024-07-12
摘要: Hydrophilic Iodized X-ray contrast medias (ICM) are difficult to separate from water. Here, a novel porous biochar (MBC) with a high specific surface area (1435.1 m g) was prepared by one-step pyrolysis, which showed excellent adsorption capacity for Iodized X-ray contrast media, including diatrizoic acid (95.1 mg g), iohexol (297.8 mg g), and iopamidol (298.9 mg g). The optimal pyrolysis temperature for MBC was 700 ℃, and the ratio of sodium hydroxide to sodium carbonate was 1:3. Adsorption kinetic was well fitted by the pseudo-second-order model. Adsorption isotherm was best fitted to the Freundlich model. Adsorption thermodynamics suggested that ICM adsorption was spontaneous and endothermic. Material characterizations demonstrated that good adsorption performance of MBC for ICM mainly depended on pore filling, π-π interaction. The density functional theory (DFT) showed that H-bonding between oxygen-containing functional groups on MBC and ICM further promoted adsorption. Recycling experiments showed that MBC had good reusability. The study indicated that one-step pyrolysis synthesis of alkaline substance pretreatment biochar could be a promising adsorbent for water purification.

52. 题目: Nitrogen fertilisation reduces the contribution of root-derived carbon to mineral-associated organic matter formation at low and high defoliation frequencies in a grassland soil
文章编号: N24071105
期刊: Plant and Soil
作者: Bahareh Bicharanloo, Milad Bagheri Shirvan, Timothy R Cavagnaro, Claudia Keitel, Feike A Dijkstra
更新时间: 2024-07-11
摘要:

Background and aims

Rhizodeposition is organic matter released by living plant roots that can be transformed by microbes into particulate organic matter (POM), but that can also become more stable through the adsorption of organic matter onto soil minerals (mineral-associated organic matter, MAOM), thereby playing an important role in mitigating climate change. We examined how root-derived carbon (C) as a proxy for rhizodeposition contributed to POM and MAOM formation in a grassland affected by nitrogen (N) fertilisation and defoliation frequency, and to what degree rhizodeposition was incorporated into microbial biomass.

Methods

We applied N fertiliser (0 vs. 40 kg N ha−1 yr−1) and defoliation frequencies (3–4 vs. 6–8 clipping events year−1, simulating low and high grazing intensity) for three years, then used a 13CO2 pulse labelling technique to examine the incorporation of rhizodeposition into microbial biomass, POM and MAOM fractions.

Results

With N fertilisation, rhizodeposition contributed less to the formation of MAOM compared to the formation of POM, while defoliation frequency decreased the contribution of rhizodeposition into both POM and MAOM, particularly with N fertilisation. Although the MAOM fraction was relatively rich in N (C: N ratio of 10.5 vs. 13.5 for POM), our results suggest that adding inorganic N promoted the formation of POM more than of MAOM from rhizodeposition.

Conclusion

A large proportion of rhizodeposition was taken up by microbes that eventually could contribute to POM and MAOM formation. Our results provide insightful information regarding the stabilisation of rhizodeposition into different soil organic matter pools.

53. 题目: Mechanistic insight into microbial interaction and metabolic pattern of anammox consortia on surface-modified biofilm carrier with extracellular polymeric substances
文章编号: N24071104
期刊: Bioresource Technology
作者: Na-Na Han, Jia-Hui Yang, Nian-Si Fan, Ren-Cun Jin
更新时间: 2024-07-11
摘要: The extremely slow growth rate of anaerobic ammonia oxidation (anammox) bacteria limits full-scale application of anammox process worldwide. In this study, extracellular polymeric substances (EPS)-coated polypropylene (PP) carriers were prepared for biofilm formation. The biomass adhesion rate of EPS-PP carrier was 12 times that of PP carrier, and EPS-PP achieved significant enrichment of BY63. The 120-day continuous flow experiment showed that the EPS-PP carrier accelerated the formation of anammox biofilm, and the nitrogen removal efficiency increased by 10.5 %. In addition, the abundance of Kuenenia in EPS-PP biofilm was 27.1%. Simultaneously, amino acids with high synthesis cost and the metabolites of glycerophospholipids related to biofilm formation on EPS-PP biofilm were significantly up-regulated. Therefore, EPS-PP carriers facilitated the rapid formation of anammox biofilm and promoted the metabolic activity of functional bacteria, which further contributed to the environmental and economic sustainability of anammox process.

54. 题目: Changes in macroaggregate stability as a result of wetting/drying cycles of soils with different organic matter and clay contents
文章编号: N24071103
期刊: Geoderma
作者: María Jesús Melej, Sara E Acevedo, Cristina P Contreras, Carolina V Giraldo, Tessa Maurer, Francisco J Calderón, Carlos A Bonilla
更新时间: 2024-07-11
摘要: The wetting–drying (WD) cycles, caused by natural or anthropogenic processes such as rainfall or irrigation, can affect many soil properties. Among these properties, soil aggregate stability has been introduced as a convenient soil health indicator because of its relation to the soil’s primary particles (sand, silt, and clay) and organic matter content (OM). However, previous studies have shown erratic effects depending on soil type and WD cycle setup when measuring aggregate stability. Therefore, this study aimed to characterize the soil primary particles composition and organic matter (OM) content of macroaggregates and measure the effects of WD cycles on aggregate stability. A series of soils with distinctive properties, such as OM and clay contents from five different USDA textural classes (loam, sandy loam, silty clay loam, silty loam, and clay loam) were used. Particle size distribution, OM, and mass fraction were measured in three aggregate size classes (2–1 mm, 1–0.5 mm, and 0.5–0.25 mm), and isolated aggregates were exposed to 3, 6, and 12 wetting and drying cycles. The main results indicate that soils with a high OM content have macroaggregates with finer particles, and the OM in soils is linearly related to the macroaggregate OM content. For 2–1 mm aggregates, a statistically significant reduction (p < 0.05) of water-stable aggregates compared to the control sample (0 cycles) was observed for every cycle, with reduction values between 4.8–7.3 %. An increase was observed only between 6–12 cycles (1.84 %). Additionally, statistically significant reductions were observed after the first three cycles in 1–0.5 mm aggregates and the first six in 0.5–0.25 mm aggregates. Finally, the macroaggregates were more resistant to the WD cycles when their clay and OM contents increased or the soil pH decreased. This study provides high-resolution results of macroaggregate particle size distribution and OM. It relates them to the effects of WD cycles in water-stable aggregates and soils with different land uses.

55. 题目: Evaluating erosion risk models in a Scottish catchment using organic carbon fingerprinting
文章编号: N24071102
期刊: Journal of Soils and Sediments
作者: C Wiltshire, J Meersmans, T W Waine, R C Grabowski, B Thornton, S Addy, M Glendell
更新时间: 2024-07-11
摘要:

Purpose

Identification of hotspots of accelerated erosion of soil and organic carbon (OC) is critical to the targeting of soil conservation and sediment management measures. The erosion risk map (ERM) developed by Lilly and Baggaley (Soil erosion risk map of Scotland, 2018) for Scotland estimates erosion risk for the specific soil conditions in the region. However, the ERM provides no soil erosion rates. Erosion rates can be estimated by empirical models such as the Revised Universal Soil Loss Equation (RUSLE). Yet, RUSLE was not developed specifically for the soil conditions in Scotland. Therefore, we evaluated the performance of these two erosion models to determine whether RUSLE erosion rate estimates could be used to quantify the amount of soil eroded from high-risk areas identified in the ERM.

Methods

The study was conducted in the catchment of Loch Davan, Aberdeenshire, Scotland. Organic carbon loss models were constructed to compare land use specific OC yields based on RUSLE and ERM using OC fingerprinting as a benchmark. The estimated soil erosion rates in this study were also compared with recently published estimates in Scotland (Rickson et al. in Developing a method to estimate the costs of soil erosion in high-risk Scottish catchments, 2019).

Results

The region-specific ERM most closely approximated the relative land use OC yields in streambed sediment however, the results of RUSLE were very similar, suggesting that, in this catchment, RUSLE erosion rate estimates could be used to quantify the amount of soil eroded from the high-risk areas identified by ERM. The RUSLE estimates of soil erosion for this catchment were comparable to the soil erosion rates per land use estimated by Rickson et al. (Developing a method to estimate the costs of soil erosion in high-risk Scottish catchments, 2019) in Scottish soils except in the case of pasture/grassland likely due to the pastures in this catchment being grass ley where periods of surface vegetation cover/root network absence are likely to have generated higher rates of erosion.

Conclusion

Selection of suitable erosion risk models can be improved by the combined use of two sediment origin techniques—erosion risk modelling and OC sediment fingerprinting. These methods could, ultimately, support the development of targeted sediment management strategies to maintain healthy soils within the EU and beyond.

56. 题目: Compositions and sources of fluorescent water-soluble and water-insoluble organic aerosols
文章编号: N24071101
期刊: Science of the Total Environment
作者: Hao Ma, Dandan Liu, Junjun Deng, Jiaming Zhao, Qiang Zhang, Zhimin Zhang, Wei Hu, Libin Wu, Pingqing Fu
更新时间: 2024-07-11
摘要: Brown carbon (BrC), the light-absorbing component of organic aerosols, plays a significant role in climate change and atmospheric photochemistry. However, the water-insoluble fractions of BrC have not been extensively studied, limiting the assessment of the overall climate effects of BrC. In this study, water-soluble and -insoluble organic carbon (i.e., WSOC and WIOC) in wintertime aerosols in Hefei were subsequently fractionated, and their fluorescence properties were comparatively investigated with the excitation–emission matrix method. WIOC contributing 57.1 % was the major component of organic carbon. WSOC with the largest contribution from humic-like regions exhibited a redshift compared to WIOC. Three humic-like substances (HULIS) with different oxidation degrees and one protein-like substances (PRLIS) were identified as the major fluorescent components by the parallel factor analysis. WSOC had more highly oxygenated HULIS, whereas low-oxygenated HULIS dominated WIOC. Nighttime WIOC contained more less-oxygenated species. The positive matrix factorization analysis suggested that biomass burning (43 %) was the largest source of both fluorescent WSOC and WIOC. Coal combustion contributed much more to fluorescent WIOC (40 %), whereas secondary formation contributed more to fluorescent WSOC (12 %). During aerosol pollution episodes, the increase in fluorescence efficiency was much greater for WIOC (25 %) than for WSOC (12 %), and WSOC and WIOC experienced a redshift and blueshift in emission wavelength, respectively. WSOC had more highly oxygenated HULIS, while WIOC had more less-oxygenated HULIS in aerosol episodes than the non-episodic periods. In addition, aerosol pollution was accompanied by the increased contributions of biomass burning and coal combustion to both fluorescent WSOC and WIOC, while the decreased relative contribution of secondary formation to fluorescent WSOC. Our findings highlighted the different fluorescence properties, compositions and sources of fluorescent WSOC and WIOC, providing a comprehensive view of BrC aerosols.

57. 题目: Metagenomic analysis reveals the mechanisms of biochar supported nano zero-valent iron in two-phase anaerobic digestion of food waste: microbial community, CAZmey, functional genes and antibiotic resistance genes
文章编号: N24071025
期刊: Journal of Environmental Management
作者: Miao Yu, Hailin Shao, Pan Wang, Lianhai Ren
更新时间: 2024-07-10
摘要: The mechanisms of biochar supported nano zero-valent iron (BC/nZVI) on two-phase anaerobic digestion of food waste were investigated. Results indicated that the performance of both acidogenic phase and methanogenic phase was effectively facilitated. BC/nZVI with the amount of 120 mg/L increased methane production by 32.21%. In addition, BC/nZVI facilitated direct interspecies electron transfer (DIET) between and methanogens. Further analysis showed that BC/nZVI increased the abundance of most CAZymes in acidogenic phase. The study also found that BC/nZVI had positive effects on metabolic pathways and related functional genes. The abundances of and in acidogenic phase were increased by 151.75% and 36.26%, respectively, and the abundances of and associated with DIET were also increased. Furthermore, BC/nZVI mainly removed , , , , , , , , , and from this system, and reduced the antibiotic resistance genes for antibiotic inactivation resistance mechanisms.

58. 题目: Organic particles and high pH in food waste anaerobic digestate enhanced NH4+ adsorption on wood-derived biochar
文章编号: N24071024
期刊: Science of the Total Environment
作者: Yunyun Zheng, Nanthi Bolan, Sasha N Jenkins, Bede S Mickan
更新时间: 2024-07-10
摘要: Biogas residues (i.e., digestate) are rich in NH that has great agricultural value but environmental risk if not recycled. Biochar can be an effective adsorbent retaining NH from digestate. However, it remains unclear how the unique composition of digestate affects the capacity and mechanisms of NH adsorption on biochar. This study examined the mechanisms and driving factors of NH recovery from digestate containing different molecular-weight organic particles by using wood-derived biochar with or without HO modification. Four solutions were prepared, including pure NH, synthetic NH with multiple cations mimicking digestate solution, supernatant of digestate with small organic particles and dissolved organic matter, and digestate mixture containing supernatant and large organic particles. The results showed that compared with pure NH solution, the adsorbed NH was 42% lower in the synthetic NH solution with multiple cations but was 2.2 time higher in the supernatant of digestate on two biochars following 48-h adsorption. Modified biochar did not change NH adsorption in pure NH solution despite higher specific surface area than raw biochar, but it increased the adsorption of NH in digestate solutions with high pH (e.g., 4.03 vs. 3.37 mg N g for modified and raw biochar, respectively, in the supernatant of digestate). Compared with the supernatant, the large organic particles in digestate mixture significantly but slightly decreased NH adsorption on modified but not raw biochar. The desorption rate of NH on the biochar was up to 74%–100%, and it was not supressed by the adsorption of organic particles in digestate. The findings here demonstrate the dominant role of electrostatic attraction in NH adsorption, the important role of high pH and organic particles in digestate in facilitating NH adsorption on biochar, and the suitability of the wood-derived biochar in recovering NH from digestate and releasing N for agricultural application.

59. 题目: Study of humic-like substances of dissolved organic matter using size exclusion chromatography and chemometrics
文章编号: N24071023
期刊: Journal of Environmental Management
作者: Sylvain Faixo, Romain Capdeville, Sofiane Mazeghrane, Mathieu Haddad, Gilberte Gaval, Etienne Paul, Florence Benoit-Marquié, Jean-Christophe Garrigues
更新时间: 2024-07-10
摘要: The study of dissolved organic matter (DOM) presents a significant challenge for environmental analyses and the monitoring of wastewater treatment plants (WWTPs). This is particularly true for the tracking of recalcitrant to biodegradation dissolved organic matter (rDOM) compounds, which is generated during the thermal pretreatment of sludge. This study aims to develop analytical and chemometric methods to differentiate melanoidins from humic acids (HAs), two components of rDOM that require monitoring at various stages of wastewater treatment processes due to their distinct biological effects. The developed method implements the separation of macromolecules through ultra-high-performance liquid chromatography size-exclusion chromatography (U-HPLC SEC) followed by online UV and fluorescence detection. UV detection was performed at 210, 254, and 280 nm, and fluorescence detection at six excitation/emission pairs: 230/355 nm, 270/355 nm, 240/440 nm, 270/500 nm, 330/425 nm, and 390/500 nm. Chromatograms obtained for each sample from these nine detection modes were integrated and separated into four molecular fractions: >40 kDa, 20–40 kDa, 10–20 kDa, and <10 kDa. To enhance analytical resolution and normalize the data, ratios were calculated from the areas of chromatographic peaks obtained for each detection mode. The results demonstrate the utility of these ratios in discriminating samples composed of HAs, melanoidins, and their mixtures, through principal component analysis (PCA). Low molecular weight fractions were found to be specific to melanoidins, while high molecular weight fractions were characteristic of HAs. For the detection modes specific to melanoidins, UV absorbance at 210, 254, and 280 nm were predominantly present in the numerators, with tryptophan-like fluorescence emissions in the denominators. Conversely, fluorescence emissions largely represented both numerators and denominators for HAs. This online method also enables the discrimination of pseudo-melanoidins, compounds revealing a nitrogen deficiency in their chemical structures.

60. 题目: Functionally-designed metal salt and ball milling co-modified sludge biochar for adsorptive removal of trace level sulfamethoxazole: Behavior, characterization, mechanism and DFT study
文章编号: N24071022
期刊: Journal of Environmental Chemical Engineering
作者: Rui Mu, Shufang Qian, Yongfei Ma, Zhikang Deng, Jiayi Tang, Zulin Zhang
更新时间: 2024-07-10
摘要: Sulfamethoxazole (SMX) is a representative sulfonamides that has been widely detected in various waters, and posing adverse effects on ecological safety and human health even at trace level. Various metal salts of ZnCl, MnCl and MgCl were applied to activate the special biochar derived from sludge (SBC), and ZnCl functionalized SBC (ZnSBC) exhibited the optimal removal capacity for SMX. Then, ball milling coupled with ZnCl was used to co-functionalize SBC to produce BZnSBC for further improving its adsorption ability. The maximum adsorption ability of BZnSBC (6.05×10 μg/g) for SMX was 8.27 times that of SBC, and it exhibited the optimum adsorption performance in the pH rang of 3–5. The outstanding elimination effect of SMX by BZnSBC (its elimination rates ranged from 90.7 % to 98.1 % in diverse real waters) was attributed to its high anti-interference to a wide range of pH, salts and humic acid concentrations. Characterization, adsorption experiments, models fitting together with DFT calculation demonstrated that π-π conjugation, pore filling, H-bonding and Zn-O complexation were the primary driving forces for SMX binding to BZnSBC. NaOH could efficiently regenerate the used BZnSBC and its adsorption capacity was 99.8 % of the original one in the fifth cyclic experiment. Also, BZnSBC performed favorable safety in view of the low leaching risk of Zn despite of pH, salts and humic acid concentrations range.

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