81. 题目: Combined land-use and street view image model for estimating black carbon concentrations in urban areas
期刊: Atmospheric Environment
作者: Xiansheng Liu, Hadiatullah Hadiatullah, Xun Zhang, Jürgen Schnelle-Kreis, Xiaohu Zhang, Xiuxiu Lin, Xin Cao, Ralf Zimmermann
摘要: In this study, we developed a novel land-use street view image random forest (LUSRF) model to estimate the equivalent black carbon (eBC) concentration based on land-use random forest (LURF) and street view imagery (SVI) models and compared their accuracy and precision in the urban city of Augsburg, Germany. The variables of the LUSRF model were constructed by combining LURF and SVI model variables (i.e., land-use, street scene, and meteorological factors). Stratified cross-validation (CV) was used to validate the model performance. Based on R2 and IA (Index of Agreement), LUSRF has superiority (average-R2: 0.73, average-IA: 0.91) compared to the LURF (average-R2: 0.52, average-IA: 0.81) and SVI model (average-R2: 0.68, average-IA: 0.89) in the urban city of Augsburg during the observed period. The main driving factors of the LUSRF model for BC estimation were different in heating and non-heating periods (i.e., elevation, the proportion of moving cars, and relative humidity for the non-heating period; and elevation, the proportion of building, and relative humidity for the heating period), which improves the estimation accuracy of eBC concentration and its sources. The model verification in other areas (i.e., suburban and small towns) further proved that the model has certain generalizability. Overall, the LUSRF model will provide insight for epidemiological studies in urban areas as a personal exposure assessment.
82. 题目: Factors that affect physicochemical and acid-base properties of compost and vermicompost and its potential use as a soil amendment
期刊: Journal of Environmental Management
作者: R. López, J. Antelo, A.C. Silva, F. Bento, S. Fiol
摘要: Composting and vermicomposting have attracted attention in relation to both waste management and the potential to produce organic amendments that could improve soil quality. The main differences between compost depend on the feedstock, the production process, and the degree of maturity. In the present study, samples of compost of different origin (food and green waste, livestock waste, algae waste, urban waste or sewage sludge) or subjected to different composting methods (traditional or using earthworms) were collected for analysis. Additionally, samples collected at various stages of the composting process were compared (raw material, 15 and 30 days of composting, and final compost). Different analysis and techniques were used to establish the chemical composition, physicochemical and acid-base properties of compost samples and the organic matter extracts. The correlations obtained (between the abundance of acid groups in different extracts of the compost or between the cation exchange capacity and the C/N atomic ratio) would allow for predicting the compost behaviour based on certain characteristics, and a reduction in the number of parameters determined experimentally, thus facilitating comparisons between different compost. In addition, the potential value of the compost as amendment was tested with a Haplic Cambisol from a mining area. The application of compost increased the pH, the organic matter and nutrient content, and promoted seed germination and root growth.
83. 题目: Modeling Photosynthesis and Exudation in Subtropical Oceans
期刊: Global Biogeochemical Cycles
作者: Zhen Wu, Stephanie Dutkiewicz, Oliver Jahn, Daniel Sher, Angelicque White, Michael J. Follows
摘要: Marine phytoplankton contributes nearly half of the total primary production on Earth through photosynthesis. Parameterizations of algal photosynthesis commonly employed in global biogeochemical simulations generally fail to capture the observed vertical structure of primary production. Here we examined the consequences of decoupling photosynthesis (carbon fixation) and biosynthesis (biomass building) with accumulation or exudation of excess photosynthate under energy rich conditions in both regional and global models. The results show that the decoupling of these two processes improved the simulated vertical profile of primary production, increased modeled primary production over 30% globally and over 40% in subtropical oceans, improved simulated meridional patterns of particulate C:N:P and increased modeled surface pool of labile/semi-labile DOC. More generally, these results highlight the importance of exudation, which results from the decoupling of photosynthesis and biosynthesis, as a major physiological process affecting ocean biogeochemistry.
84. 题目: Probing changes in humus chemical characteristics in response to biochar addition and varying bulking agents during composting: A holistic multi-evidence-based approach
期刊: Journal of Environmental Management
作者: Hong-tao Liu, Hao-nan Guo, Xiao-xia Guo, Shubiao Wu
摘要: Despite the various benefits of humus, the changes in its chemical characteristics during composting in response to biochar addition and varying bulking agents remain to be further explored. In this study, three treatments were conducted, in which swine manure, bulking agent, and biochar were mixed at ratios of 4:1:0, 8:1:0, and 8:1:1. Fourier transform infrared spectroscopy (FTIR), carbon nuclear magnetic resonance spectroscopy (13C-NMR), three-dimensional excitation-emission matrix fluorescence spectroscopy (3D-EEM), and near-edge X-ray absorption fine structure (NEXAFS) were employed to characterize the chemical and structural properties of humus from multiple perspectives. The 3D-EEM spectra in this study showed a larger increase in humic acids (HAs) content (56%) and HAs to fulvic acids ratio (128%) during composting, indicating stronger humification in biochar-amended treatment. FTIR, 13C-NMR, and NEXAFS all confirmed the essential properties of HA as the core agronomic functional substance with rich aromatic and carboxyl groups, and that its aromaticity increased gradually during composting. In addition, 13C-NMR demonstrated that biochar addition and a relatively higher bulking agent ratio aided an increase in the carboxyl C proportion in HA after composting. In particular, NEXAFS revealed that biochar addition promoted the diversification of C, N, and O species in HA, with the emergence of quinone C and O-alkyl C as the main representatives. This work suggests that biochar addition and a relatively high bulking agent ratio could enhance humification and improve the agronomic function of humus.
85. 题目: The more straw we deep-bury, the more soil TOC will be accumulated: when soil bacteria abundance keeps growing
期刊: Journal of Soils and Sediments
作者: Jiaqi Li, Xuhong Ye, Jing An, Xinxin Jin, Qingfeng Fan, Hongtao Zou, Yulong Zhang
摘要: Background Maize straw deep burying into 20–40-cm layer before covering soil and plowing ridge is a useful practice to enhance soil carbon pool and make soil bacteria rich. Purpose Now, we hope to bury much more straw to reuse the huge number of them until catching the soil environmental carrying capacity in fertility, like soil organic carbon and enzyme activities. But the reasonable straw amount to return back has not been determined. Methods Focusing on the actual output quantity of China maize straw, we designed a 7-year-term field experiment with 4 different straw deep-burying amounts of 0 t ha–1 (CK), 6 t ha–1 (SR1), 12 t ha–1 (SR2), and 18 t ha–1 (SR3). We clarified the reaction of straw amount to soil bacterial community and enzyme activities, by soil fertility, qPCR (quantitative real-time polymerase chain reaction), and Illumina high-throughput sequencing. Results According to the result, using 18 t ha–1 straw got the most enzyme activities of urease, cellulase, invertase, and dehydrogenase, more than others 4.71–332.38%. The 16S rRNA gene abundance of the sample with 18 t ha–1 straw has a significant rise compared to 0 t ha–1 (32.47%) and 6 t/ha (29.52%). Three domination bacteria of Proteobacteria, Actinobacteria, and Acidobacteria were sensitive to the straw using amount, and their relative abundance increased as straw amount enhancing. The microbial diversity changes finally increased the corn yield. Conclusion Therefore, the more straw we used, the more abundance soil bacteria and the soil TOC we would get, in the condition of straw amount under 18 t ha–1 by deep-burying method. So we should put much more straw into soil rather than abandonment.
86. 题目: Use of an ultraviolet light-activated persulfate process to degrade humic substances: effects of wavelength and persulfate dose
期刊: Environmental Science and Pollution Research
作者: Yiming Fang, Hiroshi Sakai
摘要: Natural organic matter (NOM), commonly found in surface and ground waters, form disinfection by-products in drinking water. Generally, advanced oxidation processes (AOPs) featuring hydrogen peroxide are used to treat water; however, sulfate radical recently has been used to treat recalcitrant organics, because it is associated with a higher oxidation potential and more effective removal than hydroxyl radicals. Hence, in this research, we evaluated persulfate oxidation efficiency in terms of reductions in humic substance levels and investigated the degradation mechanism. The results showed that ultraviolet-activated persulfate effectively treated humic substances compared with hydrogen peroxide and direct irradiation. Treatment was dose and wavelength dependent; higher persulfate concentrations or shorter UV wavelengths were more effective for treating humic substances as high concentration sulfate radicals were created. The degradation mechanism was similar to that of hydrogen peroxide. Aromatic and chromophore components were more susceptible to degradation than were lower molecular weight components, being initially decomposed into the latter, reducing UV254 absorbance and the SUVA254. Lower molecular weight materials were eventually degraded to end products: NPOC levels fell. And we also treated the inflow of a drinking water treatment plant with persulfate, and humic substances were effectively removed.
87. 题目: Comparison of spatiotemporal carbon, nitrogen, and phosphorus burial in two plateau lacustrine sediments: implication for N and P control
期刊: Environmental Science and Pollution Research
作者: Xiaolei Wang, Hao Yang, Bin Xue, Mingli Zhang, Benjun Yang, Changchun Huang
摘要: The long-term accumulation, burial and release of nutrients, such as carbon (C), nitrogen (N), and phosphorus (P) in lacustrine sediments are responsible for the global lake eutrophication. Interpretation of the spatiotemporal sedimentary record of nutrients (C, N, and P) in contrasting trophic level of lakes is helpful for understanding the evolutionary process of water eutrophication. Based on the radiochronology of 210Pbex and 137Cs, a comparative study of spatial and temporal concentrations, burial of total organic carbon (TOC), total nitrogen (TN), and total phosphorus (TP), the sources of organic matter were conducted using sediment cores from two plateau lakes Dianchi (DC) and Fuxian (FX) of SW China. Results showed that concentrations and burial of C, N, and P in sediments of DC, a shallow hypertrophic lake with the maximum depth of 5.8 m, were both higher than those in FX, an oligotrophic deep lake with the maximum depth of 155.0 m. For both lakes the molar ratio of TOC/TN increased in the sediments moving from north to south. The values of TOC/TN molar ratios increased over time in DC and were higher than in FX. The extremely high values of TOC/TN appeared in the central and southern parts of FX, indicating the impacts of accumulation effect and sediment focusing in the deeper region and indirect supplement from the Lake Xingyun (XY), an adjoining lake connected with FX via the Gehe River. Time-integrated sources identification in DC indicated the contribution of allochthonous sources was dominant over the past few decades, which contributed to the increased trophic level of the lake. The comparison of relationships of carbon accumulation rates (CAR), nitrogen accumulation rates (NAR), and phosphorous accumulation rates (PAR), the ratios of N/P and the utilizations of N and P fertilizer between DC and FX implied that both of N and P inputs should be limited for reducing the trophic level, but N control was predominant in comparison with P for both lakes. The results indicated that caution is required in plateau lakes to limit transition from oligotrophic to eutrophic in these lakes.
88. 题目: Exogenous fulvic acid enhances stability of mineral-associated soil organic matter better than manure
期刊: Environmental Science and Pollution Research
作者: Yang Zhang, Xiaojia Zhang, Jiong Wen, Yanan Wang, Nan Zhang, Yuehui Jia, Shiming Su, Cuixia Wu, Xibai Zeng
摘要: Mineral-associated soil organic matter (MAOM) is seen as the key to soil carbon sequestration, but its stability often varies with types of exogenous organic materials. Fulvic acid and manure are ones of the exogenous organic materials used for the improvement of degraded soil. However, little is known about if and how fulvic acid and manure affect the stability of MAOM. Using a field experiment of four fertilization treatments (no fertilization, mineral fertilizers, fulvic acid, and manure) and a comprehensive meta-analysis using relevant studies published prior to January 2020, we investigated effects of exogenous fulvic acid and manure applications on four MAOM stability indexes: association intensity, humus stabilization index, iron oxide complex coefficient, and aluminum oxide complex coefficient. Exogenous fulvic acid and manure applications increased soil organic carbon fractions by 26.04–48.47%, MAOM stability by 12.26–387.41%, and complexed iron/aluminum contents by 16.12–20.01%. Fulvic acid application increased MAOM stability by promoting mineral oxide complexation by 20.33% and manure application improved MAOM stability via increasing humus stabilization by 21–25%. Association intensity was positively correlated with contents of soil carbon fractions and the metal oxide complex coefficients were positively correlated with iron/aluminum oxide contents. Moreover, stable-humus exerted significantly positive direct and indirect effects on association intensity and humus stabilization index, while amorphous iron/aluminum content had significantly negative influences on metal oxide complex coefficients. The meta-analysis verified that long-term fulvic acid application improved MAOM stability more so than manure application in acidic soils. We recommend that strategies aiming to prevent land degradation should focus on the potential of fulvic acid as a soil amendment because it can significantly increase MAOM stability.
89. 题目: Effect of diurnal temperature range on bioleaching of sulfide ore by an artificial microbial consortium
期刊: Science of The Total Environment
作者: Xiaodi Fang, Shuiyu Sun, Xiaojian Liao, Shoupeng Li, Siyu Zhou, Qiaowei Gan, Liuting Zeng, Zhijie Guan
摘要: Temperature is considered to be one of the main factors affecting bioleaching, but few studies have assessed the effects of diurnal temperature range (DTR) on the bioleaching process. This study investigates the effects of different bioleaching temperatures (30 and 40 °C) and DTR on the bioleaching of metal sulfide ores by microbial communities. The results showed that DTR had an obvious inhibitory effect on the bioleaching efficiency of the artificial microbial community, although this effect was mainly concentrated in the early and middle stages (0–18 days) of exposure, gradually decreasing until almost disappearing in the late stage (18–24 days). Extracellular polymeric substance (EPS) analysis showed that DTR did not change the composition of the EPS matrix (humic acid-like substances, polysaccharides and protein-like substances), but had a significant effect on the generative behavior of EPS, inhibiting the secretion of EPS during the early and middle stages of the bioleaching process. However, the continual increase in EPS secretion in the bioleaching system gradually reduced the adverse effects of DTR on mineral dissolution. X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Scanning electron microscopy- energy dispersive spectrometry (SEM-EDS) analysis of the bioleached residue showed that DTR had no obvious effect on the mineralogical characteristics of sulfide ore. Therefore, in industrial sulfide ore bioleaching applications, in order to accelerate the artificial microbial community start-up process, temperature control measures should be increased in the bioleaching process to reduce the adverse effects of DTR on mineral dissolution.
90. 题目: Exploring relations between plant photochemical quantum parameters and unsaturated soil water retention for biochars and pith amended soils
期刊: Science of The Total Environment
作者: Himanshu Kumar, Suriya Prakash Ganesan, Huang Sang, Lingaraj Sahoo, Ankit Garg, Sreedeep Sekharan, Anthony K. Leung
摘要: Sustainable biomaterials such as natural fibers and biochars have been increasingly used in green infrastructures such as landfill covers for its dual-advantages of climate change mitigation and waste management. The existing studies did not systematically discuss the comparison on how biochar (stable carbon) and fiber (likely degradable), influence plant growth and water retention abilities in unsaturated soils. Also, the effect of photochemistry in the amended soils has rarely been investigated. This study addresses the limitations of previous investigations by exploring plant parameters such as photochemical yield, stomatal conductance, root area index, and unsaturated soil hydraulic parameters, including soil water retention curves (SWRC) of amended soils. Pot experiments were conducted in an environmentally controlled greenhouse. Two biochars from different plant-based feedstocks (Eichhornia crassipes, Prosopis juliflora) and one natural fiber (coir pith fiber) were mixed with soil at 5% and 10% application rate (by weight). Grass species of Axonopus compressus was planted to study the effects of different amendment materials and its corresponding plant responses during an applied drought period. The test results show that biochar amended soils increased the shoot growth by up to 100−200%. The stomatal conductance of the grass leaves increased by 54%−101% during the drought period for both biochars and coir amended soil. Furthermore, at low suction, the coir had a high-water retention capacity than the biochars, explaining the observed higher stomatal conductance values. Importantly, it was discovered that the plant photochemical quantum yield responses associated with plant wilting was found to be between 1500 and 1800 kPa for all the soil treatments. The study concludes with a newly developed mathematical expression based on the measurements of plant parameters and soil suction. The new equation could be used to optimize the irrigation frequency in order to apply any informed measures to maintain green infrastructures.
91. 题目: Long-term partial substitution of chemical fertilizer with green manure regulated organic matter mineralization in paddy soil dominantly by modulating organic carbon quality
期刊: Plant and Soil
作者: Peidong Xu, Ji Wu, Hui Wang, Shang Han, Jun Zhu, Qingling Fu, Mingjian Geng, Hongqing Hu, Qiaoyun Huang
摘要: Purpose The purpose of this study was to investigate the response characteristics and potential mechanisms of soil organic matter (SOM) mineralization to the ten years partial substitution of chemical fertilizer with green manure in paddy soil. Methods The mineralization of SOM in paddy soil treated with no fertilizer, complete chemical fertilizer, and chemical fertilizer partially substituted with increasing amount of green manure was investigated by incubation experiments. The CO2 released during the incubation was determined by gas chromatography. The chemical structure and pool of soil organic carbon was analyzed by nuclear magnetic resonance and acid hydrolysis, respectively. Soil microbial communities and the abundance of organic carbon hydrolase genes were analyzed by high-throughput sequencing and quantitative polymerase chain reaction, respectively. Random forest analysis was used to analyze the roles of related factors in the mineralization of SOM. Results The mineralization of SOM was significantly suppressed by chemical fertilizer, but the suppression was alleviated or reversed by the partial substitution of chemical fertilizer with increasing amount of green manure. The quality of soil organic carbon showed a similar tendency to the mineralization of SOM. Fertilization treatments, especially those with green manure, significantly increased soil organic carbon quantity and the activity of organic carbon hydrolases. Fertilization treatments also significantly changed the composition of microbial communities, but had no significant influence on the abundance of the genes encoding hydrolases. Conclusion Long-term partial substitution of chemical fertilizer with green manure regulated organic matter mineralization in paddy soil dominantly by modulating organic carbon quality.
92. 题目: Performance of different pretreatment methods on alleviating reverse osmosis membrane fouling caused by soluble microbial products
期刊: Journal of Membrane Science
作者: Gen-Qiang Chen, Yin-Hu Wu, Pin-Sheng Fang, Yuan Bai, Zhuo Chen, Yu-Qing Xu, Yun-Hong Wang, Xing Tong, Li-Wei Luo, Hao-Bin Wang, Zi-Wei Zhang, Nozomu Ikuno, Hong-Ying Hu
摘要: Soluble microbial products (SMP) are one of the main causes of reverse osmosis (RO) membrane fouling in wastewater reclamation, and coagulation and adsorption are commonly used to prevent such fouling. However, the mechanism by which typical coagulants and adsorbents affect the RO membrane fouling caused by SMP remains unclear. In this study, two bacterial strains isolated from fouled RO membranes in a full-scale wastewater reclamation plant were used to produce SMP. Both bacterial strains were found to generate high SMP yield (0.23–0.25 g/g), which caused severe RO membrane fouling. Coagulation by polyaluminum chloride (PACl) and ferric chloride (FeCl3) and adsorption by granular activated carbon (GAC) were applied as pretreatment methods to alleviate the membrane fouling caused by SMP. Compared with PACl, FeCl3 performed better in removing SMP, decreasing fluorescence intensity, and reducing molecular weight (MW). GAC preferentially adsorbed protein and humic substances in SMP and unselectively and efficiently removed fluorescent compounds; however, it could only remove a limited amount of the high-MW compound. The RO membrane fouling potential of treated SMP was investigated, and FeCl3 and GAC were found to effectively alleviate the fouling. In addition to a decrease in the dissolved organic carbon content of SMP, a decrease in specific fluorescence intensity, MW, and polysaccharide content caused by coagulation or adsorption could result in lower RO membrane fouling.
93. 题目: Quantification of soil organic carbon at regional scale: Benefits of fusing vis-NIR and MIR diffuse reflectance data are greater for in situ than for laboratory-based modelling approaches
作者: Michael Vohland, Bernard Ludwig, Michael Seidel, Christopher Hutengs
摘要: Benefits of fusion approaches for visible to near (vis-NIR) and mid-infrared (MIR) chemometric modelling have been studied to some extent for laboratory-based soil studies, but little is known about the usefulness and limitations for in situ studies. Objectives were to compare laboratory-based and in situ vis-NIR and MIR partial least squares (PLS) and bagging-PLS regression approaches and to explore the potentials of combining both types of spectral data for the quantification of soil organic carbon (SOC). We applied different established low-level (spectra concatenation, outer product fusion approach) and high-level (averaging of vis-NIR and MIR modelling results) data fusion methods. The studied set comprised a total of 186 soil samples collected in Saxony-Anhalt and northern Saxony, Central Germany. One subset (Querfurt Plateau) covered 90 finely-textured soils originating from the Chernozem soil region, another (Düben Heath) with 96 samples was characterized by a wider pedological variety. Vis-NIR and MIR diffuse reflectance spectra were measured in situ on the soil surface and in the laboratory on pre-treated (dried and finely ground) soil material with the ASDFieldSpec4 and the Agilent 4300 Handheld FTIR instruments. We found a regionally stratified approach to be beneficial for accurate estimations for both laboratory and in situ data. For laboratory spectra, MIR outperformed vis-NIR data in both regions (Querfurt Plateau: r2 = 0.85 vs. 0.65, RMSE = 0.11 (in % SOC) vs. 0.17; Düben Heath: 0.77 vs. 0.69 (r2) and 0.27 vs. 0.40 (RMSE)). Ranking for in situ data was the same, but accuracies decreased markedly. With MIR, r2 amounted to 0.58 and RMSE was 0.20 for the Querfurt Plateau (vis-NIR: r2 = 0.26, RMSE = 0.27); for Düben Heath, r2 was 0.60 and RMSE was 0.39 for MIR data, while vis-NIR resulted in an r2 of 0.53 and an RMSE of 0.43. For the studied samples, which had medium to low water contents (0.68 to 16.8 wt%, median at 5.4 wt%), we found accuracies with both spectral datasets to be similarly affected by in situ conditions. Model ensemble averaging based on bagging-PLS regression was the most efficient approach to improve SOC estimation accuracies with in situ spectral data, whereas model averaging was in general of little effect for laboratory data. Improvements were most marked for the in situ data of the Düben Heath region, where r2 increased to a value of 0.77 and RMSE decreased to 0.28. Low-level data fusion methods did not yield any improvements compared to model ensemble averaging. For the latter, we identified averaging with weights derived sample-wise from uncertainties in the bootstrap-based modelling as being most accurate, but with little benefits compared to a simple (unweighted) averaging of vis-NIR and MIR estimates. Our results suggest that already a simple averaging procedure has the potential to advance multi-sensor applications integrating vis-NIR and MIR data for in situ or on-site soil spectroscopy. This applies especially to regions with heterogeneous soil conditions, tied to spectral variablity, as this increases the probability of complementary vis-NIR and MIR information and their prospective fusion.
94. 题目: Carbon and nitrogen isotope constraints on source and variation of particulate organic matter in high-latitude agricultural rivers, Northeast China
期刊: Journal of Cleaner Production
作者: Sen Xu, Fu-Jun Yue, Si-Liang Li, Hu Ding, Sheng Xu, Yun-Chao Lang, Cong-Qiang Liu
摘要: The stored organic matter (OM) in the humus-rich black soils of Northeast China is highly susceptible to permafrost thaw and agriculturally induced erosion processes, playing a disproportionate role in the global carbon cycle. However, the perturbations of global change and anthropogenic activities on riverine export of particulate organic carbon (POC) in the high-latitude agricultural areas remain poorly constrained. In the present study, the characteristics of particulate organic matter (POM) and the erosional flux of POC from the rivers draining Northeast China was studied. The elemental (POC%, PON% and C/N ratio) and isotopic (δ13C and δ15N) compositions of POM in suspended particulate matter (SPM) from the rivers in Northeast China (the Songhua River (SRB) and Liao River basins (LRB)) were analyzed. The results showed that during the wet season, the δ13C and δ15N values of POM in SPM were −25.8 ± 1.2‰ and 6.6 ± 2.2‰ respectively. Elemental and isotopic characteristics of the SPM samples and potential sources indicated that the sources of POM differed significantly among different sampling periods and sites. During the wet season, Soil OM was the primary POM contributor. Compared to the SRB, autochthonous OM made relatively larger contributions to POM in the LRB. During the dry season, for the SPM samples mainly from the LRB, the δ13C and δ15N values of POM were −22.7 ± 4.3‰ and 3.1 ± 2.4% respectively, suggesting that effluent detritus was the predominant source. The flux and yield of SPM revealed the seasonal and spatial variations of physical erosion rate that controls POC export. Seasonally, up to 61% of the annual SPM load and 58% of the annual POC flux of the SRB occurred in May and August due to thawing processes and increasing precipitation. Spatially, the lower reaches of the SRB had the highest SPM yield and contributed more than half of the annual SPM load of the SRB, likely attributable to the high intensity of agricultural activities. Globally, the POC% in SPM and POC yield of the SRB were larger than a series of the world's largest rivers under a given SPM condition, suggesting the high sensitivity of terrestrial OM export to erosion. These findings highlight the perturbation and mobilization of terrestrial OM in Northeast China under intensive agricultural activities and ongoing global climate change.
95. 题目: Effects of Three Commonly Used Herbicides in Maize on Short-Term Soil Organic Carbon Mineralization
期刊: Water, Air, & Soil Pollution
作者: Burak Koçak, Sahin Cenkseven
摘要: Toxicological effects of herbicides on the non-target microorganisms in the soil that play important roles in degrading organic matter, nutrient cycling, and decomposition should be considered if they were applied at higher concentrations. This study was conducted to reveal the toxicity of three modern herbicides (dicamba + tritosulfuron; DT, isoxinutole + thlencarbuone-methyl + cyprosulfamide; ITC and nicosulfuron; N) on soil carbon mineralization for short term. Recommended concentration (25 g/day for DT1, 30 ml/day for ITC1, and 125 ml/day N1), its 5 (DT5, ITC5, and N5), and 10 (DT10, ITC10, and N10) folds of herbicides were applied on a clay soil with no pesticide application history. Soil + herbicide mixes and soil without herbicide as control were incubated under constant temperature (28 °C) and moisture (80% of soil field capacity) for 42 days. In general, all doses of herbicides were significantly decreased soil carbon mineralization in short term (P < 0.05). Cumulative carbon mineralization was declined for 3.4% by DT1, for 15.0% by DT5, for 22.4% by DT10, for 13.7% by ITC1, for 14.2% by ITC5, for 18.6% by ITC10, for 4.7% by N1, for 10.0% by N5, and for 21.0% by N10, respectively, compared to control. Significant decreases were observed in the rates of carbon mineralization except DT1 and N1. Results suggested that higher doses of these herbicides negatively affected on soil microbial respiration.
96. 题目: High-Resolution Modeling and Apportionment of Diesel-Related Contributions to Black Carbon Concentrations
期刊: Environmental Science & Technology
作者: Sofia D. Hamilton, Robert A. Harley
摘要: Exposure to diesel-related air pollution, which includes black carbon (BC) as a major component of the particulate matter emitted in engine exhaust, is a known human health hazard. The resulting health burden falls heavily on vulnerable communities located close to major sources including highways, rail yards, and ports. Determination of source contributions to the overall pollution burden is challenging due to collinearity in the exhaust composition profiles for relevant sources including heavy-duty diesel trucks, railroad locomotives, cargo-handling equipment, and marine engines. Additionally, the impact of each source depends not just on the magnitude of emissions but on its location relative to receptors as well as on meteorology. We modeled source-resolved BC concentrations in West Oakland, California, at a high (150 m) spatial resolution using the Weather Research and Forecasting model. The ability of the model to predict hourly and 24 h average BC concentrations is evaluated for a 100-day period in summer 2017 when BC was measured at 100 sites within the community. We find that a community monitoring site is representative of population-weighted average BC exposure in the community. Major contributing sources to BC in West Oakland include on-road diesel trucks (44 ± 5%) and three off-road diesel sources: ocean-going vessels (19 ± 1%), railroad locomotives (16 ± 2%), and harbor craft such as tugboats and ferries (11 ± 1%).
97. 题目: Incorporation of hydrogen from ambient water into the C-bonded H pool during litter decomposition
期刊: Soil Biology and Biochemistry
作者: Arnim Kessler, Katharina Kreis, Stefan Merseburger, Wolfgang Wilcke, Yvonne Oelmann
摘要: Aridity was observed to affect the C-bonded stable H isotope ratios (δ2Hn values) of aboveground plant organic matter but not δ2Hn values of associated soil organic matter (SOM). Instead, δ2Hn values of SOM correlated spatially with long-term mean δ2H values of local rainfall. To explain this discrepancy, we investigated if and to which degree C-bonded H was replaced by ambient water-H during leaf litter decomposition in laboratory microcosms. In a four-week incubation of leaf litter (Fagus sylvatica l. - beech, Acer pseudoplatanus l. - maple) with two H-isotopically labeled waters (δ2Hiw: +50‰, +250‰), we found a small incorporation of isotopically labeled H into the C-bonded H pool (<5% of total C-bonded H) in beech litter. For the leached, more reactive total organic matter in solution (TOM), we estimated that 8–9% of C-bonded H was replaced by the isotope label during incubation. We suggest that the small incorporation of H from ambient water can be attributed to microbial processes. However, the small incorporation of H from ambient water during microbial processing would not be sufficient to overprint the aridity signal present in plant organic matter and shift δ2Hn values of SOM towards those of long-term rainfall. This supports the suggestion, that SOM originates from belowground sources including roots and microorganisms, which inherently show δ2Hn values related with those of long-term rainfall.
98. 题目: Black carbon over a high altitude Central Himalayan Glacier: Variability, transport, and radiative impacts
期刊: Environmental Research
作者: K. Sandeep, A.S. Panicker, Alok Sagar Gautam, G. Beig, Naveen Gandhi, Sanjeev S, , H.C. Nainwal
摘要: Ambient equivalent black carbon (BC) measurements spanning from June to October have been carried out over an adjoining location of Satopanth and Bhagirath-Kharak Glaciers (3858m, amsl) of Central Himalaya during the year 2019. Hourly BC varied from 12 ng m−3 to 439 ng m−3 during the entire period of observation. Monthly averaged BC values showed the highest concentration during June (230.96 ± 85.46 ng m−3) and the lowest in August (118.02 ± 71.63 ng m−3). The decrease in BC during monsoon months is attributed to limited long-range transport and rapid wet scavenging processes. Transport model studies indicate a higher retention time of tracer in Uttarakhand, Punjab, Haryana, and adjacent polluted valley regions with increased biomass burning (BB) incidences. The high rate of BC influx during June, September, and October was attributed to transport from the polluted Indo-Gangetic Plain (IGP) region, wildfires, and vehicular emissions in the valley region. Higher equivalent brown carbon (BrC) influx is linked to BB, especially wood-burning, during intense forest fires at slopes of mountains. Data obtained from limited BC observations during the 2011–19 period showed no significant BC influx change during post-monsoon. The strong correlation between BC mass and BB affirms the dominant role of BB in contributing BC to the Glacier region. Increased TOA forcing induced by surface darkening and BC atmospheric radiative heating indicate an additional warming and possible changes of the natural snow cycle over the glacier depending on the characteristics and extent of debris cover.
99. 题目: Evaluation of influential factors in microwave assisted pyrolysis of sugarcane bagasse for biochar production
期刊: Environmental Technology & Innovation
作者: Mari Selvam S., Balasubramanian Paramasivan
摘要: Microwave assisted pyrolysis (MAP) is an efficient technology for the production of biochar. However, its large-scale application is limited due to lack of process optimization resulting in lower yield. Identification of significantly influencing parameters is essential for efficient optimization. Thus, in present study, screening of factors like the feedstock amount, feedstock size, moisture content, catalyst dosage, microwave power and exposure time using half fractional factorial screening design was done to identify the most influencing factor affecting sugarcane bagasse biochar yield. The formulated linear model was found to be significant with a regression coefficient (R2) of 0.9365. Half normal plot and the Pareto chart analysis showed the MAP to be mostly influenced by the feedstock amount, microwave irradiation time, feedstock size and microwave power. Maximum biochar yield of 44.46% was obtained with 10 g feedstock (0.015 cm) at 720 W after 20 min, which would be optimized further to improvise the process efficiency.
100. 题目: Deep winter intrusions of urban black carbon into a canyon near Santiago, Chile: A pathway towards Andean glaciers
期刊: Environmental Pollution
作者: Nicolás Huneeus, Rémy Lapere, Andrea Mazzeo, César Ordóñez, Nicolas Donoso, Ricardo Muñoz, José A. Rutllant
摘要: Black carbon transport from the Santiago Metropolitan Area, Chile, up to the adjacent Andes Cordillera and its glaciers is of major concern. Its deposition accelerates the melting of the snowpack, which could lead to stress on water supply in addition to climate feedback. A proposed pathway for this transport is the channelling through the network of canyons that connect the urban basin to the elevated summits, as suggested by modelling studies, although no observations have validated this hypothesis so far. In this work, atmospheric measurements from a dedicated field campaign conducted in winter 2015, under severe urban pollution conditions, in Santiago and the Maipo canyon, southeast of Santiago, are analysed. Wind (speed and direction) and particulate matter concentrations measured at the surface and along vertical profiles, demonstrate intrusions of thick layers (up to 600 m above ground) of urban black carbon deep into the canyon on several occasions. Transport of PM down-valley occurs mostly through shallow layers at the surface except in connection with deep valley intrusions, when a secondary layer in altitude with return flow (down-valley) at night is observed. The transported particulate matter is mostly from the vicinity of the entrance to the canyon and uncorrelated to concentrations observed in downtown Santiago. Reanalyses data show that for 10% of the wintertime days, deep intrusions into the Maipo canyon are prevented by easterly winds advecting air pollutants away from the Andes. Also, in 23% of the cases, intrusions proceed towards a secondary north-eastward branch of the Maipo canyon, leaving 67% of the cases with favourable conditions for deep penetrations into the main Maipo canyon. Reanalyses show that the wind directions associated to the 33% anomalous cases are related to thick cloud cover and/or the development of coastal lows.