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321. 题目: Fractionation of levofloxacin and ofloxacin during their transport in NOM-goethite: Batch and column studies
文章编号: N22110105
期刊: Environmental Pollution
作者: Xiaopeng Qin, Xiaofei Zhong, Bin Wang, Guangcai Wang, Fei Liu, Liping Weng
更新时间: 2022-11-01
摘要:

Adsorption and transport of levofloxacin (LEV) and ofloxacin (OFL) enantiomers in a matrix containing goethite and natural organic matter (NOM) were investigated using batch and column experiments. In batch studies, competition and enantioselectivity were observed in the adsorption of LEV and OFL. Enantioselectivity upon adsorption was investigated by comparing changes in the enantiomer fraction (EF) (the ratio of LEV to the sum of LEV and OFL remaining in the solution) after and before adsorption. At pH < 7, there was hardly any selectivity in adsorption of OFL and LEV to goethite. At pH > 7, OFL showed a stronger adsorption than LEV to goethite, and this preference remained when NOM samples of Leonardite humic acid (LHA) and Elliott Soil fulvic acid (ESFA) were added. However, when Suwannee River NOM (SRNOM) was added, the preference was reversed, and LEV was adsorbed more strongly. In single systems, the presence of different types of NOM increased adsorption of LEV and OFL, especially LEV. In column studies, preloaded NOM decreased the transport of LEV and OFL through goethite-coated sand. The EF values in the effluent increased with retention time and reached the largest values (0.59–0.72) at around 1.5 pore volume (PV), and then decreased again, reaching a stable value at 5.0–30.0 PV. Both batch and column experiments showed that, fractionation of LEV and OFL occurred during adsorption and transport in the presence of NOM-goethite complexes, which would eventually affect their environmental fate.

322. 题目: NOM fractionation by HPSEC-DAD-OCD for predicting trihalomethane disinfection by-product formation potential in full-scale drinking water treatment plants
文章编号: N22110104
期刊: Water Research
作者: Meritxell Valenti-Quiroga, Pepus Daunis-i-Estadella, Pere Emiliano, Fernando Valero, Maria J Martin
更新时间: 2022-11-01
摘要:

Chlorination is a common method for water disinfection; however, it leads to the formation of disinfection by-products (DBPs), which are undesirable toxic pollutants. To prevent their formation, it is crucial to understand the reactivity of natural organic matter (NOM), which is considered a dominant precursor of DBPs. We propose a novel size exclusion chromatography (SEC) approach to evaluate NOM reactivity and the formation potential of total trihalomethanes-formation potentials (tTHMs-FP) and four regulated species (i.e. CHCl3, CHBrCl2, CHBr2Cl, and CHBr3). This method combines enhanced SEC separation with two analytical columns working in tandem and quantification of apparent molecular weight (AMW) NOM fractions using C content (organic carbon detector, OCD), 254-nm spectroscopic (diode-array detector, DAD) measurements, and spectral slopes at low (S206-240) and high (S350-380) wavelengths. Links between THMs-FP and NOM fractions from high performance size exclusion chromatography HPSEC-DAD-OCD were investigated using statistical modelling with multiple linear regressions for samples taken alongside conventional full-scale as well as full- and pilot-scale electrodialysis reversal and bench-scale ion exchange resins. The proposed models revealed promising correlations between the AMW NOM fractions and the THMs-FP. Methodological changes increased fractionated signal correlations relative to bulk regressions, especially in the proposed HPSEC-DAD-OCD method. Furthermore, spectroscopic models based on fractionated signals are presented, providing a promising approach to predict THMs-FP simultaneously considering the effect of the dominant THMs precursors, NOM and Br.

323. 题目: Particulate and mineral-associated organic carbon fractions reveal the roles of soil aggregates under different land-use types in a karst faulted basin of China
文章编号: N22110103
期刊: Catena
作者: Xiaoyu Peng, Yong Huang, Xingwu Duan, Hua Yang, Jiaxin Liu
更新时间: 2022-11-01
摘要:

Soil aggregation has been recognized as the main mechanism of organic carbon (C; OC) stabilization, and OC dynamics within aggregates are closely linked to soil OC (SOC) sequestration. To unravel the roles of different-sized aggregates and the associated OC fractions in SOC accumulation, SOC stocks (SOCS), aggregate distributions, and OC fractions within aggregates were measured under five typical land-use types (cropland, grassland, shrubland, plantation forest, and natural forest) in a karst faulted basin, China. Land-use type had distinct effects on SOCS in the topsoil (0–10 cm) and along the soil profile (0–60 cm), and the primary factors influencing SOCS varied with the soil horizons. Plantation forest had the highest SOCS (51.2 Mg C ha−1) in the topsoil, whereas the SOCS in shrubland (182.7 Mg C ha−1) was distinctively higher than those of other land-use types across the soil profile. Soil microbial biomass C and mean weight diameter were the major factors driving SOCS variation in the topsoil layer and the entire soil profile, respectively. OC content within macroaggregates (>0.25 mm) was significantly positively correlated with the SOC content of bulk soil, whereas only the mass proportion of large macroaggregates (>2 mm) showed a positive relationship with SOC. Additionally, mineral-associated OC (MAOC) was the dominant fraction of SOC and was abundant in macroaggregates. However, particulate OC (POC) within aggregates was relatively enriched in the topsoil and microaggregates. Considering the decomposition and distribution characteristics of OC fractions in different-sized aggregates, we suggest that the POC/MAOC ratios of macro- and microaggregates could respectively reflect aggregate capacity to sequestrate MAOC and POC across different land-use types. Overall, shrubland is the optimal land-use type for rocky desertification control in the karst fault basin, due to the protection of POC and MAOC within different-sized aggregates.

324. 题目: Combined effects of photoaging and natural organic matter on the colloidal stability of nanoplastics in aquatic environments
文章编号: N22110102
期刊: Water Research
作者: Yanghui Xu, Qin Ou, Xiaoming Li, Xintu Wang, Jan Peter van der Hoek, Gang Liu
更新时间: 2022-11-01
摘要:

The transport and fate of nanoplastics (NPs) in aquatic environments are closely associated with their colloidal stability, which is affected by aging and natural organic matter (NOM) adsorption. This study systematically investigated the combined effects of photoaging and NOM (e.g. humic acids, HA; and a model protein, bovine serum albumin, BSA) on the aggregation kinetics of NPs (polystyrene, PS) in NaCl and CaCl2 solutions. Our results showed that photoaged NPs adsorbed less HA than pristine NPs due to weaker hydrophobic and π-π interactions. In return, HA showed weaker impacts on NPs’ stability after photoaging. Differently, photoaged NPs absorbed more BSA than pristine NPs due to stronger hydrogen bonding and electrostatic attraction. Thus, the inhibitory effects of BSA on the aggregation kinetics of NPs were enhanced after photoaging. Regarding the effects of NOM on the aging of NPs, our results showed that HA competed with NPs for photons and underwent photo-degradation. Subsequently, the destruction/reconstruction of adsorbed HA increased (in NaCl) or decreased (in CaCl2) the stability of NPs. Notably, light radiation-induced flocculation of BSA molecules, which wrapped and integrated NPs and lead to their destabilization. Overall, this study provided new insights into the aggregation behavior of NPs in aquatic systems, which have significant implications for predicting the transport and fate of NPs in complex real-world environments.

325. 题目: Application of predictor variables to support regression kriging for the spatial distribution of soil organic carbon stocks in native temperate grasslands
文章编号: N22110101
期刊: Journal of Soils and Sediments
作者: Yuqiang Li, Xuyang Wang, Yun Chen, Xiangwen Gong, Caiping Yao, Wenjie Cao, Jie Lian
更新时间: 2022-11-01
摘要:

Purpose

As the main component of terrestrial carbon pool, soil organic carbon (SOC) is vital to soil fertility and biogeochemical cycle. Quantifying the spatial distribution of regional SOC stocks (SOCS) provides critical support for climate change and food security decisions. Our aim was to explore the optimal interpolation method to improve the accuracy of spatial prediction of SOCS in temperate grasslands.

Materials and methods

To support such research, we performed soil sampling to depths of 0 to 20 and 20 to 30 cm throughout the Hulun Buir grassland of Inner Mongolia. We compared prediction of the spatial patterns of SOCS using regression kriging (RK) and ordinary kriging (OK). We used topographic factors, climate variables, satellite data (the normalized-difference vegetation index (NDVI)), and soil texture as predictors in the RK method.

Results and discussion

SOCS was significantly positively correlated with precipitation, NDVI, topographic variables, and clay content, but negatively correlated with temperature and sand content. NDVI explained more than 40% of the SOCS spatial variation and was the dominant factor. Geostatistical analysis showed strong and moderate spatial dependence of SOCS in the 0–20- and 20–30-cm soil layers, respectively. The RK and OK soil pools to a depth of 30 cm were 607.28 and 559.46 Tg, respectively.

Conclusion

Compared with OK, the RK method improved the SOCS prediction accuracy by 20.4, 30.1, and 23.9% for soil depths of 0–20, 20–30, and 0–30 cm, respectively. Our findings suggest that OK may be acceptable where the environmental conditions are homogeneous, but that RK performs better in heterogeneous areas.

326. 题目: The remediation of di-(2-ethylhexyl) phthalate-contaminated sediments by water hyacinth biochar activation of calcium peroxide and its effect on cytotoxicity
文章编号: N22103106
期刊: Environmental Research
作者: Chang-Mao Hung, Chin-Pao Huang, Shu-Ling Hsieh, Ya-Ting Chen, Chiu-Wen Chen, Cheng-Di Dong
更新时间: 2022-10-31
摘要:

The presence of di-(2-ethylhexyl) phthalate (DEHP) in the aquatic systems, specifically marine sediments has attracted considerable attention worldwide, as it enters the food chain and adversely affects the aquatic environment and subsequently human health. This study reports an efficient carbocatalytic activation of calcium peroxide (CP) using water hyacinth biochar (WHBC) toward the efficient remediation of DEHP-contaminated sediments and offer insights into biochar-mediated cellular cytotoxicity, using a combination of chemical and bioanalytical methods. The pyrolysis temperature (300–900 °C) for WHBC preparation significantly controlled catalytic capacity. Under the experimental conditions studied, the carbocatalyst exhibited 94% of DEHP removal. Singlet oxygen (1O2), the major active species in the WHBC/CP system and electron-rich carbonyl functional groups of carbocatalyst, played crucial roles in the non-radical activation of CP. Furthermore, cellular toxicity evaluation indicated lower cytotoxicity in hepatocarcinoma cells (HepG2) after exposure to WHBC (25–1000 μg mL−1) for 24 h and that WHBC induced cell cycle arrest at the G2/M phase. Findings clearly indicated the feasibility of the WHBC/CP process for the restoration of contaminated sediment and contributing to understanding the mechanisms of cytotoxic effects and apoptotic of carbocatalyst on HepG2.

327. 题目: Enhanced removal of fluoroquinolone antibiotics by peroxydisulfate activated with N-doped sludge biochar: performance, mechanism and toxicity evaluation
文章编号: N22103105
期刊: Separation and Purification Technology
作者: Zhihuang Fang, Shirong Zhao, Gang Xue, Xiaonuan Wang, Peizhe Sun, Yang Yu, Zilin Zhou, Qi Wang, Yajie Qian
更新时间: 2022-10-31
摘要:

N-modified sludge-derived biochar (N-SDBC) was prepared and then used for activation of peroxydisulfate (PDS) to degrade fluoroquinolone antibiotics (FQs). Seven commonly used FQs were degraded by N-SDBC/PDS effectively, with the rate constants from 0.131 min-1 to 0.505 min-1. Scavenging experiments combined with electron paramagnetic resonance (EPR) confirmed that 1O2 was the dominated reactive species, and the radicals SO4•- and OH played minor roles. In-depth study revealed that the graphite-N and Fe0 on the surface of N-SDBC were the main active sites for PDS activation. The elevated N precursors and calcination temperature enhanced the yields of graphite-N and Fe0. Products analysis indicated enrofloxacin degradation by 1O2 with the fragmentation of the piperazine ring, the disconnection of the quinolone ring, decarboxylation, and defluorination. The toxicity assessment by Escherichia coli and ECOSAR showed that the biological toxicity of ENR could be reduced after treating by N-SDBC/PDS. The application in surface water and wastewater samples demonstrates the efficiency of FQs removal by N-SDBC/PDS.

328. 题目: Biochar decreases and nitrification inhibitor increases phosphorus limitation for microbial growth in a wheat-canola rotation
文章编号: N22103104
期刊: Science of the Total Environment
作者: Prem Pokharel, Scott X Chang
更新时间: 2022-10-31
摘要:

Agricultural management practices affect microbial populations and ecoenzymatic activities; however, the effect of these practices on ecological stoichiometry relating the elemental ratio of resources to microbial biomass is poorly understood. In a 2-year field study, we assessed the effects of biochar and nitrapyrin (a commonly used nitrification inhibitor (NI)) on the ecological stoichiometry and microbial nutrient limitation in a wheat (Triticum aestivum L.)-canola (Brassica juncea L.) rotation. This study used a 3 × 2 factorial design that included two treatments: (i) biochar with three levels: no biochar addition (BC0), and biochar added at 10 (BC10) and 20 t ha−1 (BC20), and (ii) NI with two levels: without (NI0) and with NI (NI1). Soil microbial biomass carbon (C), nitrogen (N) and phosphorus (P) were increased by biochar application, regardless of the application rate, but were not affected by NI application. Biochar increased and NI decreased β-1,4-glucosidase, β-1,4-N-acetyl glucosaminidase and acid phosphatase (P < 0.05) with subsequent changes in ecoenzymatic stoichiometry. Ecoenzymatic stoichiometry analysis showed microbial P limitation relative to N in the studied area irrespective of the treatment, with contrasting effects of biochar (decreasing) and NI (increasing) on the vector angle of ecoenzymatic stoichiometry (P = 0.037 and 0.043, respectively). Biochar applied at 20 t ha−1 decreased the threshold elemental ratio of C:P at which microbial growth switches between nutrient and C limitations, suggesting a shift towards C relative to nutrient (P) limitation. This study concludes that biochar produced from manure compost can be useful in increasing microbial growth by alleviating P limitations in a wheat-canola rotation.

329. 题目: Ball milling Fe3O4@biochar cathode coupling persulfate for the removal of sulfadiazine from water: effectiveness and mechanisms
文章编号: N22103103
期刊: Journal of Environmental Chemical Engineering
作者: Taiqing Wei, Yang Meng, Dan Ai, Chi Zhu, Bo Wang
更新时间: 2022-10-31
摘要:

This study used biochar as the substrate of the electrodes, and a simple synthetic process (ball milling) was adopted to prepare the Fe3O4@biochar cathode enhanced coupled system of electrochemistry-potassium persulfate to achieve the efficient removal of sulfadiazine. Studies showed that the cracking temperature of biochar and the iron-to-carbon mass ratio determined the catalytic performance of cathodes. In addition, ball milling increased the surface functional groups of biochar and promoted the dispersion of Fe3O4 on biochar, leading to increased active sites on the Fe3O4@biochar cathode surface. It was found that SDZ and TOC removal rates reached 95.3% and 86.9% in the coupled system of electrochemical-persulfate with SDZ concentration of 10 mg/L, initial pH0 of 7, PDS concentration of 4 mM, current density of 30 mA/cm2, and electrode plate spacing of 4 cm. Also, this system showed excellent removal of sulfadiazine in actual water bodies. The quenching experiments and electron paramagnetic resonance spectra revealed that free radicals and non-radicals were involved in removing sulfadiazine, with free radicals (SO4•−) being the dominant pathway. Four main degradation pathways were proposed based on the intermediates of sulfadiazine. In conclusion, Fe3O4@biochar cathode enhanced coupled system of electrochemical-persulfate could be regarded as an efficient cleaning technology to provide a method for the removal of intractable organic pollutants.

330. 题目: Atmospheric Black Carbon Loadings and Sources over Eastern Sub-Saharan Africa Are Governed by the Regional Savanna Fires
文章编号: N22103102
期刊: Environmental Science & Technology
作者: Leonard Kirago, Örjan Gustafsson, Samuel M Gaita, Sophie L Haslett, H Langley deWitt, Jimmy Gasore, Katherine E Potter, Ronald G Prinn, Maheswar Rupakheti, Jean de Dieu Ndikubwimana, Bonfils Safari, August Andersson
更新时间: 2022-10-31
摘要: Vast black carbon (BC) emissions from sub-Saharan Africa are perceived to warm the regional climate, impact rainfall patterns, and impair human respiratory health. However, the magnitudes of these perturbations are ill-constrained, largely due to limited ground-based observations and uncertainties in emissions from different sources. This paper reports multiyear concentrations of BC and other key PM2.5 aerosol constituents from the Rwanda Climate Observatory, serving as a regional receptor site. We find a strong seasonal cycle for all investigated chemical species, where the maxima coincide with large-scale upwind savanna fires. BC concentrations show notable interannual variability, with no clear long-term trend. The Δ14C and δ13C signatures of BC unambiguously show highly elevated biomass burning contributions, up to 93 ± 3%, with a clear and strong savanna burning imprint. We further observe a near-equal contribution from C3 and C4 plants, irrespective of air mass source region or season. In addition, the study provides improved relative emission factors of key aerosol components, organic carbon (OC), K+, and NO3, in savanna-fires-influenced background atmosphere. Altogether, we report quantitative source constraints on Eastern Africa BC emissions, with implications for parameterization of satellite fire and bottom-up emission inventories as well as regional climate and chemical transport modeling.

331. 题目: Potential influence of fine aerosol chemistry on the optical properties in a semi-arid region
文章编号: N22103101
期刊: Environmental Research
作者: Pengfei Tian, Naiyue Zhang, Jiayun Li, Xiaolu Fan, Xu Guan, Yuting Lu, Jinsen Shi, Yi Chang, Lei Zhang
更新时间: 2022-10-31
摘要:

The current understanding regarding the potential influence of aerosol chemistry on the optical properties does not satisfy accurate evaluation of aerosol radiative effects and precise determination of aerosol sources. We conducted a comprehensive study of the potential influence of aerosol chemistry on the optical properties in a semi-arid region based on various observations. Organic matter was the main contributor to the scattering coefficients followed by secondary inorganic aerosols in all seasons. We further related aerosol absorption to elemental carbon, organic matter, and mineral dust. Results showed that organic matter and mineral dust contributed to >40% of the aerosol absorption in the ultraviolet wavelengths. Therefore, it is necessary to consider the absorption of organic matter and mineral dust in addition to that of elemental carbon. We further investigated the potential influence of chemical composition, especially of organic matter and mineral dust on the optical parameters. Mineral dust contributed to higher absorption efficiency and lower scattering efficiency in winter. The absorption Ångström exponent (AAE) was mostly sensitive to organic matter and mineral dust in winter and spring, respectively; it was relatively high (i.e., 1.68) in winter and moderate (i.e., 1.42) in spring. Unlike in the other seasons, mineral dust contributed to higher mass absorption efficiency in winter. This work reveals the complexity of the relationship between aerosol chemistry and optical properties, and especially the influence of organic matter and mineral dust on aerosol absorption. The results are highly important regarding both regional air pollution and climate.

332. 题目: Evidence from molecular marker and FT-ICR-MS analyses for the source and transport of dissolved black carbon under variable water discharge of a subtropical Estuary
文章编号: N22103002
期刊: Biogeochemistry
作者: Weiqiang Zhao, Hongyan Bao, Dekun Huang, Jutta Niggemann, Thorsten Dittmar, Shuh-Ji Kao
更新时间: 2022-10-30
摘要:

Dissolved black carbon (DBC) is the largest known refractory organic carbon pool in the ocean. However, processes in estuaries connecting rivers (a significant DBC source) and oceans are underexplored. We carried out two sampling campaigns in the Jiulong River estuary (JRE) and conducted a dissolved organic matter (DOM) mixing experiment. DBC was quantified by the benzenepolycarboxylic acid (noted as DBC-BPCA) method and characterized with Fourier transform ion cyclotron resonance mass spectrometry (noted as DBC-FT). The molecular formulae of DBC-FT in the JRE were also compared with that in soil and atmospheric deposition. Overall, DBC-BPCA was removed during seaward dispersion. Soil- and deposition-derived molecules were identified in the DBC-FT of the JRE, confirming deposition inputs to estuarine DBC for the first time. The salinity-dependent decrease in the intensity normalized modified aromatic index (AImod) of DBC-FT and in DBC-BPCA revealed that DBC composition and concentration were primarily controlled by mixing. However, photodegradation and particle adsorption/flocculation may play a role in removing DBC depending on the concentration of total suspended matter (TSM). The two campaigns showed that high discharge increased both riverine input and estuarine output of DBC. However, the removal patterns of DBC-BPCA were minimally influenced by discharge. We further estimated that approximately 20% DBC-BPCA was lost in this estuary annually. Future studies should investigate the transformation of DBC in coastal bays and the open ocean where the residence time is longer and the transparency of bulk water is higher.

333. 题目: Lack of nitrogen fertilizer rate effects on soil carbon and nitrogen supply capacity: evidence from a 10-year trial
文章编号: N22103001
期刊: Plant and Soil
作者: Allison Bailey, Ken Janovicek, Paul Voroney, Bill Deen, Joshua Nasielski
更新时间: 2022-10-30
摘要:

Background and aims

The long-term effects of annual fertilizer nitrogen (N) applications on soil organic carbon (SOC) has important implications for cropping system productivity and climate change mitigation. To understand the impacts of N fertilizer on SOC and other soil properties in a corn-based cropping system, a 10-year (2009–2018) study was initiated in Elora, Ontario, Canada.

Methods

Corn was grown every year and crop management was held constant aside from the N rate applied. Plots received one of six long-term N rates (range: 30 to 260 kg-N ha-1). SOC (0–20 cm) was measured in every plot at the start and end of the study.

Results

N fertilizer rate increased both grain yield (range: 5.6 to 11.0 Mg ha-1) and residue biomass (range: 5.0 to 7.6 Mg ha-1). Harvest index also increased significantly with N application (range: 0.49 to 0.55). Assuming a fixed harvest index would have overestimated residue returns. SOC increased by a similar amount after 10 years in all N rate treatments (mean: 4.5 Mg-C ha-1). Soil N supply capacity assessed at the end of the experiment was also unaffected by long-term N rate as measured by total soil N (0-20 cm), corn yield planted after trial conclusion (2019) and results from a 10-week incubation study.

Conclusions

N rate had no detectable effect on SOC, N supply capacity or aggregate stability after 10 years. While yield and residue C inputs did increase with N rate, assuming a constant harvest index of 0.5 would have overestimated actual residue C returns.

334. 题目: Hitchhiking into the Deep: How Microplastic Particles are Exported through the Biological Carbon Pump in the North Atlantic Ocean
文章编号: N22102916
期刊: Environmental Science & Technology
作者: Luisa Galgani, Isabel Goßmann, Barbara Scholz-Böttcher, Xiangtao Jiang, Zhanfei Liu, Lindsay Scheidemann, Cathleen Schlundt, Anja Engel
更新时间: 2022-10-29
摘要: Understanding residence times of plastic in the ocean is a major knowledge gap in plastic pollution studies. Observations report a large mismatch between plastic load estimates from worldwide production and disposal and actual plastics floating at the sea surface. Surveys of the water column, from the surface to the deep sea, are rare. Most recent work, therefore, addressed the “missing plastic” question using modeling or laboratory approaches proposing biofouling and degradation as the main removal processes in the ocean. Through organic matrices, plastic can affect the biogeochemical and microbial cycling of carbon and nutrients. For the first time, we provide in situ measured vertical fluxes of microplastics deploying drifting sediment traps in the North Atlantic Gyre from 50 m down to 600 m depth, showing that through biogenic polymers plastic can be embedded into rapidly sinking particles also known as marine snow. We furthermore show that the carbon contained in plastic can represent up to 3.8% of the total downward flux of particulate organic carbon. Our results shed light on important pathways regulating the transport of microplastics in marine systems and on potential interactions with the marine carbon cycle, suggesting microplastic removal through the “biological plastic pump”.

335. 题目: Dynamics of soluble soil organic matter in Mediterranean maize-based forage system under organic and mineral fertilization
文章编号: N22102915
期刊: Catena
作者: Giovanna Seddaiu, Maria Vittoria Pinna, Alberto Agnelli, Chiara Cappai, Giuseppe Corti, Clara Ella Demurtas, Antonio Pulina, Pier Paolo Roggero
更新时间: 2022-10-29
摘要:

In Nitrate Vulnerable Zones (NVZ), the impact of animal effluent management on soil fertility is essential. A three-year study was carried out in a NVZ (Arborea, Central-western Sardinia, Italy), aiming to analyze the effect of different fertilization systems on soluble and total soil organic matter (SOM) within a silage maize-hay crop cropping system on sandy soil (Oxyaquic Xeropsamment). Four types of fertilization systems were compared: (i) cattle manure; (ii) cattle slurry; (iii) mineral; (iv) slurry + mineral. The water-extractable C and N content (WEC and WEN) from the topsoil (0–20 cm layer, the Ap1 horizon), the dissolved carbon (DC) and the dissolved nitrogen (DN) of the soil solution collected by disk lysimeters placed along the soil profiles, and the C content at the beginning and at the end of the experiment were determined.

The seasonal dynamics of WEC in the topsoil seemed mainly associated with the timing of the fertilizer distribution. In the topsoil, WEC was larger under slurry than under mineral treatment. The DC was rather low in the deeper soil layers and did not show any variation due to the fluctuations of fertilizer distribution that were seemingly influenced by the groundwater table. The fertilization systems influenced the soil C inputs and, in turn, the SOM content. Manure promoted a higher C stock in the deeper soil layers among the organic fertilizers. However, the hay crop added with manure and slurry showed lower crop residues and, thus, C input than that added with mineral fertilizer. This result suggests that the management of these organic fertilizers should carefully consider their impact on the overall productivity of the studied cropping system in Mediterranean NVZ to avoid a potential limitation for soil C accumulation in the long term.

336. 题目: Spatiotemporal pattern of ecosystem respiration in China estimated by integration of machine learning with ecological understanding
文章编号: N22102914
期刊: Global Biogeochemical Cycles
作者: Lang Han, Gui-Rui Yu, Zhi Chen, Xian-Jin Zhu, Wei-Kang Zhang, Tie-Jun Wang, Li Xu, Shi-Ping Chen, Shao-Min Liu, Hui-Min Wang, Jun-Hua Yan, Jun-Lei Tan, Fa-Wei Zhang, Feng-Hua Zhao, Ying-Nian Li, Yi-Ping Zhang, Li-Qing Sha, Qing-Hai Song, Pei-Li Shi, Jiao-Jun Zhu, Jia-Bing Wu, Zhong-Hui Zhao, Yan-Bin Hao, Xi-Bin Ji, Liang Zhao, Yu-Cui Zhang, Shi-Cheng Jiang, Feng-Xue Gu, Zhi-Xiang Wu, Yang-Jian Zhang, Li Zhou, Ya-Kun Tang, Bing-Rui Jia, Gang Dong, Yan-Hong Gao, Zheng-De Jiang, Dan Sun, Jian-Lin Wang, Qi-Hua He, Xin-Hu Li, Fei Wang, Wen-Xue Wei, Zheng-Miao Deng, Xiang-Xiang Hao, Xiao-Li Liu, Xi-Feng Zhang, Xing-Guo Mo, Yong-Tao He, Xin-Wei Liu, Hu Du, Zhi-Lin Zhu
更新时间: 2022-10-29
摘要: Accurate estimation of regional and global patterns of ecosystem respiration (ER) is crucial to improve the understanding of terrestrial carbon cycles and the predictive ability of the global carbon budget. However, large uncertainties still exist in regional and global ER estimation due to the drawbacks of modelling methods. Based on eddy covariance ER data from 132 sites in China from 2002 to 2020, we established Intelligent Random Forest (IRF) models that integrated ecological understanding with machine learning techniques to estimate ER. The results showed that the IRF models performed better than semiempirical models and machine learning algorithms. The observed data revealed that gross primary productivity (GPP), living plant biomass, and soil organic carbon (SOC) were of great importance in controlling the spatiotemporal variability of ER across China. An optimal model governed by annual GPP, living plant biomass, SOC, and air temperature (IRF-04 model) matched 93% of the spatiotemporal variation in site-level ER, and was adopted to evaluate the spatiotemporal pattern of ER in China. Using the optimal model, we obtained that the annual value of ER in China ranged from 5.05 to 5.84 Pg C yr-1 between 2000 and 2020, with an average value of 5.53 ± 0.22 Pg C yr-1. In this study, we suggest that future models should integrate process-based and data-driven approaches for understanding and evaluating regional and global carbon budgets.

337. 题目: Integrating Biochar, Bacteria, and Plants for Sustainable Remediation of Soils Contaminated with Organic Pollutants
文章编号: N22102913
期刊: Environmental Science & Technology
作者: Leilei Xiang, Jean Damascene Harindintwali, Fang Wang, Marc Redmile-Gordon, Scott X Chang, Yuhao Fu, Chao He, Bertrand Muhoza, Ferdi Brahushi, Nanthi Bolan, Xin Jiang, Yong Sik Ok, Jörg Rinklebe, Andreas Schaeffer, Yong-Guan Zhu, James M Tiedje, Baoshan Xing
更新时间: 2022-10-29
摘要: The contamination of soil with organic pollutants has been accelerated by agricultural and industrial development and poses a major threat to global ecosystems and human health. Various chemical and physical techniques have been developed to remediate soils contaminated with organic pollutants, but challenges related to cost, efficacy, and toxic byproducts often limit their sustainability. Fortunately, phytoremediation, achieved through the use of plants and associated microbiomes, has shown great promise for tackling environmental pollution; this technology has been tested both in the laboratory and in the field. Plant–microbe interactions further promote the efficacy of phytoremediation, with plant growth-promoting bacteria (PGPB) often used to assist the remediation of organic pollutants. However, the efficiency of microbe-assisted phytoremediation can be impeded by (i) high concentrations of secondary toxins, (ii) the absence of a suitable sink for these toxins, (iii) nutrient limitations, (iv) the lack of continued release of microbial inocula, and (v) the lack of shelter or porous habitats for planktonic organisms. In this regard, biochar affords unparalleled positive attributes that make it a suitable bacterial carrier and soil health enhancer. We propose that several barriers can be overcome by integrating plants, PGPB, and biochar for the remediation of organic pollutants in soil. Here, we explore the mechanisms by which biochar and PGPB can assist plants in the remediation of organic pollutants in soils, and thereby improve soil health. We analyze the cost-effectiveness, feasibility, life cycle, and practicality of this integration for sustainable restoration and management of soil.

338. 题目: Humification improvement by optimizing particle size of bulking agent and relevant mechanisms during swine manure composting
文章编号: N22102912
期刊: Bioresource Technology
作者: Minna Jiao, Xiuna Ren, Yifeng He, Juan Wang, Cuihuan Hu, Zengqiang Zhang
更新时间: 2022-10-29
摘要:

For purpose of clarifying the impact on particle size of bulking agents on humification and relevant mechanisms, different length (<2 cm, 2cm, 5cm, 10 cm) of branch and straw were blended with swine manure individually for 100 days aerobic composting. Results demonstrated that, 2 cm and 5 cm of branch and straw promoted the highest degradation of DOC by 41.49% and 58.42%, and increase the humic substances by 23.81% and 55.82% in maturity stage, respectively, compared with other treatments. As shown in microbial consequence, the maximum relative abundance of humus funguses increased by 99.55% and 99.92% at phylum, and 98.95% and 99.24% at genus in 2 cm and 5cm of branch and straw treatment, thus verifying the result in variation of humus content. In a word, particle size could result in obvious impact on humification, and the optimized size were about 2 cm and 5 cm of branch and straw.

339. 题目: A RUpture-Based detection method for the Active mesopeLagIc Zone (RUBALIZ): A crucial step toward rigorous carbon budget assessments
文章编号: N22102911
期刊: Limnology and Oceanography: Methods
作者: Robin Fuchs, Chloé M J Baumas, Marc Garel, David Nerini, Frédéric A C Le Moigne, Christian Tamburini
更新时间: 2022-10-29
摘要: Determining mesopelagic organic carbon budgets is essential to characterize the ocean's role as a carbon dioxide sink. This is because the biological processes observed in the mesopelagic zone are crucial for understanding the biological carbon pump. Yet, field assessments of carbon budgets are often unbalanced with the carbon demand exceeding its supply. This underlines either methodological issues in the budget calculations or incomplete knowledge of the mesopelagic carbon cycling with potentially missing sources. Carbon budgets are built by partitioning the ocean into vertical depth zones. Vertical boundaries are conventionally defined between 200 and 1000 m depth or using various thresholds. Such approaches lack consistent methodology preventing robust comparison of mesopelagic carbon budget from region to region. Here, using a statistical rupture detection method applied to conductivity–temperature–depth (CTD)-cast variables (fluorescence, O2 concentration, potential temperature, salinity, and density), we aim to provide independent estimates of mesopelagic boundaries. We demonstrate that the so-determined upper boundary is highly correlated with the knee points of the particulate organic carbon (POC) fluxes estimated by a power law and that over 90% of the POC flux attenuation occurs within our method boundaries. The identified zone therefore corresponds to the most active part of the conventional mesopelagic zone and we name it the “active mesopelagic zone” (AMZ). We find that the depths of the mesopelagic zone depend on the region considered. Our results demonstrate that the mesopelagic carbon budget discrepancy can vary up to four folds depending on the boundaries chosen and hence provide novel grounds to reassess existing and future mesopelagic carbon budgets.

340. 题目: Singlet Oxygen Seasonality in Aqueous PM10 is Driven by Biomass Burning and Anthropogenic Secondary Organic Aerosol
文章编号: N22102910
期刊: Environmental Science & Technology
作者: Sophie Bogler, Kaspar R Daellenbach, David M Bell, André S H Prévôt, Imad El Haddad, Nadine Borduas-Dedekind
更新时间: 2022-10-29
摘要: The first excited state of molecular oxygen is singlet-state oxygen (1O2), formed by indirect photochemistry of chromophoric organic matter. To determine whether 1O2 can be a competitive atmospheric oxidant, we must first quantify its production in organic aerosols (OA). Here, we report the spatiotemporal distribution of 1O2 over a 1-year dataset of PM10 extracts at two locations in Switzerland, representing a rural and suburban site. Using a chemical probe technique, we measured 1O2 steady-state concentrations with a seasonality over an order of magnitude peaking in wintertime at 4.59 ± 0.01 × 10–13 M and with a quantum yield of up to 2%. Next, we identified biomass burning and anthropogenic secondary OA (SOA) as the drivers for 1O2 formation in the PM10 aqueous extracts using source apportionment data. Importantly, the quantity, the amount of brown carbon present in PM10, and the quality, the chemical composition of the brown carbon present, influence the concentration of 1O2 sensitized in each extract. Anthropogenic SOA in the extracts were 4 times more efficient in sensitizing 1O2 than primary biomass burning aerosols. Last, we developed an empirical fit to estimate 1O2 concentrations based on PM10 components, unlocking the ability to estimate 1O2 from existing source apportionment data. Overall, 1O2 is likely a competitive photo-oxidant in PM10 since 1O2 is sensitized by ubiquitous biomass burning OA and anthropogenic SOA.

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