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13201. 题目: Linking landscape heterogeneity with lake dissolved organic matter properties assessed through absorbance and fluorescence spectroscopy: Spatial and seasonal patterns in temperate lakes of Southern Andes (Patagonia, Argentina)
文章编号: N19060803
期刊: Science of The Total Environment
作者: Claudia Queimaliños, Mariana Reissig, Gonzalo L. Pérez, Carolina Soto Cárdenas, Marina Gerea, Patricia E. Garcia, Daniel García, María C. Diéguez
更新时间: 2019-06-08
摘要: Hydrological connectivity between terrestrial and aquatic systems is influenced by landscape features. Topography, vegetation cover and type, lake morphometry and climate (seasonality, precipitation) drive the timing, concentration and quality of allochthonous dissolved organic matter (DOM) inputs to lakes, influencing lake metabolism. The impact of climate changes on terrestrial-aquatic linkages depends on regional trends and ecosystems properties. We examined how landscape heterogeneity affects lake DOM in pristine temperate headwater lakes located in sharp bioclimatic gradients at the leeward side of the southern Andes (Patagonia, Argentina), and predicted their potential responses to forecasted changes in regional climate. We assessed DOM properties of deep and shallow lakes spotted along precipitation and altitudinal gradients which reflect on vegetation heterogeneity. Lake DOM (concentration, and chromophoric and fluorescent properties) was related to terrestrial bioclimatic conditions, addressing also DOM bio- and photodegradation processes. Co-effects of climate and vegetation determined the quantity and quality of allochthonous DOM inputs. Higher terrestrial signs showed up at the wettest extreme of the gradient and during the rainy season, being attributable to higher hydrological land-water connectivity, and dense vegetation cover. Under drier conditions, DOM displayed higher photobleaching signs at spatial and temporal scales. The ratio between non-humic and terrestrial humic substances indicated that DOM biodegradation dominates in shallow forested lakes and photodegradation prevails in deep ones, whereas coupled photo- and biological processing shaped the DOM pool of high altitude lakes. Overall, DOM optical metrics captured landscape heterogeneity. Under the forecasted climate changes for Patagonia (decreasing precipitation and increasing temperature), piedmont lakes may experience lower hydrological connectivity, lower terrestrial inputs and, enhanced photobleaching usually associated with longer water residence time. In high altitude lakes, terrestrial DOM inputs are expected to increase due to the upward expansion of native deciduous forests, thus becoming more similar to lakes located lower in the landscape.
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13202. 题目: Increasing the ability of a green roof to provide ecosystem services by adding organic matter and earthworms
文章编号: N19060802
期刊: Applied Soil Ecology
作者: My Dung Jusselme, Charlotte Pruvost, Eric Motard, Stéphanie Giusti-Miller, Sophie Frechault, Vanessa Alphonse, Clarisse Balland-Bolou-Bi, Isabelle Dajoz, Philippe Mora
更新时间: 2019-06-08
摘要: The aim of this study was to increase the ecosystem services provided by a green roof by ameliorating the biological and chemical properties of a commercial green roof substrate through the addition of earthworms and compost. We conducted a mesocosm (120 × 80 × 33 cm) experiment with a plant community comprising Hylotelephium maximum,Centaurea jacea, Lotus corniculatus, Koeleria glauca, and Dianthus carthusianorum. Two substrates were compared (i) a low complexity commercial green roof substrate with no alterations and (ii) a high complexity substrate with a layer of locally produced vermicompost and earthworms (Lumbricus terrestris) placed on top of the commercial substrate. The mesocosms were placed on the roof of a 20 m high building and at ground level.Results show that the percent of vegetative cover on both substrates was lower in the roof mesocoms than on those placed at ground level. This is explained by climatic conditions, such as higher light intensity at roof level. The substrate with earthworms and vermicompost had significantly higher enzyme activity, microbial biomass, and metabolic activity. This resulted in more available nitrogen and phosphorus for plants, increased the plant biomass, floral nectar volume and sugar concentration which resulted in the flowers receiving more diverse and abundant insect pollinators. This is the first time that adding earthworms and compost to a green roof substrate has been shown to have a significant effect on plant growth and plant-pollinator interactions. These findings will help in designing green roof systems that are more efficient at preserving ecosystem services in urban areas.

13203. 题目: Aggregation of TiO2 and Ag nanoparticles in soil solution – Effects of primary nanoparticle size and dissolved organic matter characteristics
文章编号: N19060801
期刊: Science of The Total Environment
作者: Lisa Zehlike, André Peters, Ruth H. Ellerbrock, Laura Degenkolb, Sondra Klitzke
更新时间: 2019-06-08
摘要: The colloidal stability of nanoparticles NP in soil solution is important to assess their potential effects on ecosystems. The aim of this work was to elucidate the interactions between initial particle size di, particle number concentration (N0) as well as the characteristics of dissolved organic matter (DOM) for stabilizing Ag NP and TiO2 NP.In batch experiments using time-resolved dynamic light scattering (DLS), we investigated the aggregation of TiO2 NP (79 nm, 164 nm) and citrate-stabilised Ag NP (73 nm, 180 nm) in Ca2+ solution (2 mM) and two soil solutions, one extracted from a farmland and one from a floodplain soil (each containing 2 mM Ca2+).Our results demonstrate that the initial particle size and the particle number concentration affected aggregation more strongly in the presence of DOM than without DOM. The composition of DOM also affected aggregate size: NP formed larger aggregates in the presence of hydrophilic DOM than in the presence of hydrophobic DOM. Hydrophilic DOM showed a larger charge density than hydrophobic DOM. If Ca2+ is present, it may bridge DOM molecules, which may lead to greater NP destabilization. The results demonstrate that DOM interaction with NP may not only vary for different DOM characteristics (i.e. charge density) but may also be influenced by the presence of multivalent cations and different NP material; thus the effect of DOM on NP colloidal stability is not uniform.
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13204. 题目: Chemical composition of downward fluxes in the Cretan Sea (Eastern Mediterranean) and possible link to atmospheric deposition: A 7 year survey
文章编号: N19060718
期刊: Deep Sea Research Part II: Topical Studies in Oceanography
作者: C. Theodosi, Z. Markaki, F. Pantazoglou, A. Tselepides, N. Mihalopoulos
更新时间: 2019-06-07
摘要: To better assess the role of atmospheric deposition on seawater productivity in the Eastern Mediterranean 200 sinking particulate matter samples have been collected at two different depths in the water column (500 and 1715 m from the surface) during a seven-year period (1999–2005). The samples were analysed for various nutrients and elements of both natural and anthropogenic origin such as nitrogen (N), phosphorus (P), Organic Matter, CaCO3, Si, Al, Ca, V, Cr, Mn, Fe, Ti, Ni, Cu, Zn, Cd and Pb. Moreover, sediment traps data were #compared with atmospheric deposition to assess possible transfer mechanisms of material from the atmosphere to the water column. The amount of dissolved inorganic nitrogen (DIN) deposited via atmosphere was higher up to a factor of 6 compared to the dissolved organic nitrogen (DON) collected at the sediment traps, indicating significant external N deposition. On the other hand, atmospheric dissolved inorganic phosphorus (DIP) deposition accounted for only 60% of the P measured at upper sediment traps indicating less significant role of the atmosphere for P compared to N. Atmospheric dust was found to be transferred almost quantitatively from the atmosphere to the deeper water layers, indicating significant impact of vertical mass transfer. The rapid vertical mass transfer during spring can be attributed to the formation of big aggregates with atmospheric dust particles, which settle quite fast. During summer and autumn mass transfer is hindered due to the stratification of the water column and low primary productivity.

13205. 题目: Effects of contrasting biochars on the leaching of inorganic nitrogen from soil
文章编号: N19060717
期刊: Journal of Soils and Sediments
作者: Ying Feng, Xing Yang, Bhupinder Pal Singh, Sanchita Mandal, Jia Guo, Lei Che, Hailong Wang
更新时间: 2019-06-07
摘要: Purpose: The use of excessive nitrogen (N) fertilizers usually causes soil N leaching, eutrophication, and water pollution. Nevertheless, biochars may play an important role in decreasing N losses from soil to waterways. The objectives of this study were to explore the effect of contrasting biochars on the leaching of key inorganic N species during the N transformation processes in a biochar-amended soil. Materials and methods: A column leaching experiment was carried out through a soil treated with 2% (w/w) application rate of dead pig-derived biochar (DPB), ultrasonic-modified dead pig-derived biochar (UPB), or Platanus orientalis branch-derived biochar (POB). The DPB contained 5% N, which was much greater than that in the POB (1% N). The amount of ammonium and nitrate N (NH4+-N and NO3-N) in the leachate samples from the soil treated with different biochars were collected and analyzed periodically. Results and discussion: After 20 weeks of incubation, the cumulative NH4+-N leaching loss from the control treatment was 1.87, 2.00, and 2.07 times greater than that from the POB-, DPB-, and UPB-treated soils (P < 0.05). Biochar application reduced NH4+-N leaching from the soil, likely because of NH4+ ion retention and adsorption on biochar surface areas and pore spaces. The cumulative NO3-N in the leachate from the biochar-amended soil was significantly lower than that of the untreated control, in the order of POB < UPB = DPB < untreated control. With the application of DPB and UPB, the cumulative inorganic N (especially NO3-N) leaching loss was significantly higher by up to 50%, compared with the POB treatment (P < 0.05). The suppression of nitrate leaching may be due to microbial N immobilization, resulting from the addition of different biochars. It is apparent that the ultrasonic modification process of DPB caused no further inhibition of inorganic N leaching from the soil via incorporating the UPB. Conclusions: Despite the relatively high N concentration in the DPB, 2% of DPB dosage reduced inorganic N leaching from the amended soil. Therefore, regardless of the biochar N concentrations, biochars could be used to improve N fertilizer use efficiency by reducing N leaching loss from soils.

13206. 题目: Hydrological and ecological controls on autochthonous carbonate deposition in lake systems: a case study from Lake Wuliangsu and the global perspective
文章编号: N19060716
期刊: Geophysical Research Letters
作者: Dayang Sun, Yuxin He, Jinglu Wu, Weiguo Liu, Yongge Sun
更新时间: 2019-06-07
摘要: Based on ~150‐year of sedimentary records, we identify that autochthonous carbonate deposition in Lake Wuliangsu, in the upper reaches of the Yellow River, was independent of both hydrological and ecological variations before 1965, influenced by hydrological changes due to agricultural activities during 1965–1990, and slightly impacted by higher productivity under the eutrophication process after 1990. By comparing with data from lakes across the globe, we find that lake size and lake stratification control the contribution of recycled organic carbon to autochthonous carbonate deposition. Continuous mixing and aeration in shallow lakes facilitate the transformation of organic carbon into 29–45% of sedimentary carbonate, different from large and deep lakes (2–25%). Organic carbon recycling in lakes remains generally stable or decreases under the pressure of lake eutrophication, requiring further investigations on whether more organic carbon will be buried in the carbonate form.

13207. 题目: Removal of sulfamethoxazole (SMX) in sulfate-reducing flocculent and granular sludge systems
文章编号: N19060715
期刊: Bioresource Technology
作者: Lin-Qing Qiu, Liang Zhang, Kai Tang, Guanghao Chen, Samir Kumar Khanal, Hui Lu
更新时间: 2019-06-07
摘要: This study investigated sulfamethoxazole (SMX) removal and fate in sulfate-reducing up-flow sludge bed (SRUSB) reactors inoculated with sulfate-reducing bacteria (SRB) granules and flocs. The resilience of SRB granules and flocs against varying pHs and hydraulic retention times (HRTs) was also examined. SRB granules and flocs efficiently removed SMX from wastewater, which was significantly higher than the aerobic sludge. SRB granules achieved significantly (p < 0.05) higher SMX removal (∼13.3 μg/g suspended solids (SS)-d) than the SRB flocs (∼11.2 μg/g SS-d) during 150-day of SRUSB reactors operation. The SMX removal by both granules and flocs was mainly attributed to biodegradation. Sorption also contributed to SMX removal, in which aromatic protein-like substances of extracellular polymeric substances played important role in SMX removal. In addition, SRB granules showed higher resilience than SRB flocs against varying pHs and HRTs. Thus, SRB-mediated biological process, especially SRB granules, could be a promising biotechnology to remove SMX from wastewaters.
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13208. 题目: In situ biochar capping is feasible to control ammonia nitrogen release from sediments evaluated by DGT
文章编号: N19060714
期刊: Chemical Engineering Journal
作者: Yaoyao Zhu, Baoqing Shan, Jianyin Huang, Peter R. Teasdale, Wenzhong Tang
更新时间: 2019-06-07
摘要: Evaluation of in situ capping with biochar (BC) to control ammonia nitrogen (NH4+-N) release from the sediments of Baiyangdian Lake, the largest freshwater lake in northern China, was performed after 10 months of field and mesocosm experiments. The concentration of NH4+-N in pore water and its resupply from native sediments and capped sediments were determined using the technique of diffusive equilibrium in thin films (DET) and the technique of diffusive gradients in thin films with CMI-7000 cation ion exchange membrane (CMI-DGT) binding layer. The results showed a low concentration of NH4+-N in pore water and a low resupply from the sediment or capping materials after BC capping. The concentration of bioavailable NH4+-N measured by DGT of the top 4 cm layer in BC capping layer was only 12.8%−29.2% of the native sediments. Flux DET-NH4+-N, could be reduced from 12.74 to 3.44 mg·m−2·d−1 and Flux DGT-NH4+-N was further reduced from 13.38 to 1.59 mg·m−2·d−1. The calculated concentration gradient at the sediment-water interface following the capping treatment was lower than the control. These results implied that BC capping reduced the release of NH4+-N from the sediments. The low resupply from the sediments was further demonstrated by the smaller ratio of CDGT to CDET (R) in the BC capping layer, which their average values were 0.48, 0.59, 0.68 in the BC capping layer, BC/soil layer and native sediments, respectively. The physical, chemical and microbiological effects were attributed to inhibit the NH4+-N release from sediments by the BC capping.
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13209. 题目: Combined process of visible light irradiation photocatalysis-coagulation enhances natural organic matter removal: Optimization of influencing factors and mechanism
文章编号: N19060713
期刊: Chemical Engineering Journal
作者: Nan Wang, Xing Li, Yanling Yang, Yi Shang, Xiaoxuan Zhuang, Hang Li, Zhiwei Zhou
更新时间: 2019-06-07
摘要: Photocatalysis or coagulation process has been separately studied for the removal of natural organic matter (NOM) from surface water, and the reaction mechanism of organic fractionations of treated effluent has been clarified. Although coagulation-based process has been extensively studied for NOM removal, few attempts have been made based on a combined process that can not only efficiently degrade NOM, but also enhance the coagulation performance. The hypothesis is that a combination of photocatalysis and coagulation process in a single unit might potentially enhance NOM removal efficiency. This is because the nano-photocatalyst can serve as both pre-oxidant and flocculation core. Herein, a combined process of visible light photocatalysis prior to coagulation is conducted, with the transformation efficiency of the organics fractionations revealed. The as-prepared nano-sized photocatalyst consisting of Bi2O3-TiO2 (molar Bi/Ti ratio 0.04:1) had a stronger visible light absorption ability. Compared to coagulation alone, the combined photocatalysis-coagulation process greatly improved NOM removal, with synergistic effect, while the pre-photocatalysis reduced the required dosage of polyaluminium chloride (PACl) coagulant and increased the optimal pH of solution. A mathematical model optimized by response surface methodology of the combined process was developed that produced a good correlation between predicted and experimental values. The optimal conditions were calculated as follow: 2.0 g/L photocatalyst, a photocatalytic reaction time of 10 min 18 sec, 0.04 mM PACl coagulant, and a pH of 4.2. These conditions particularly enhanced removal of acidic hydrophobic substance, humic-/protein-like substances and fractions with molecular weight between 3 and 44 kDa. The XRD spectra and SEM images of the produced flocs identified that these flocs consisted of a core of photocatalyst, which could contribute to an effective flocculation and enhanced NOM removal.
图文摘要:

13210. 题目: Sulfur isotopic composition of gas-phase organic sulfur compounds provides insights into the thermal maturation of organic-rich rocks
文章编号: N19060712
期刊: Geochimica et Cosmochimica Acta
作者: Alon Amrani, Yoav Oved Rosenberg, Alexander Meshoulam, Ward Said-Ahmad, Courtney Turich, Nathalie Luu, Tracey Jacksier, Artur Stankiewicz, Shimon Feinstein, Avital Shurki
更新时间: 2019-06-07
摘要: Volatile and gas phase organic sulfur compounds (VOSCs) are important components in subsurface reservoir fluids and despite their relatively low concentrations, can provide important information about organic matter origin, diagenetic transformation, thermal maturation, and oil and gas generation, expulsion, and migration. We present an approach for the utilization of VOSC concentration and compound specific S isotopes ratio (δ34S) data as a new geochemical tool to study natural gas origin and formation. We studied the formation pathways of VOSCs, their δ34S values, and interaction with an organic-rich sedimentary rock (or ‘source rock’) from the Ghareb Formation (Type II-S kerogen) deposited in an upwelling marine environment. The immature source rock was subjected to laboratory controlled thermal maturation. We used a semi-open, non-isothermal pyrolysis system heated between 200 and 440 °C, and analyzed the molecular composition and compound specific δ34S values of the evolved gases at various thermal maturity stages. Formation of VOSCs commenced at 206°C, a temperature generally associated with less thermally mature systems, and typically before the onset of oil generation for similar organic-rich source rocks, allowing study of low thermal maturity conditions (∼0.3 %Roe). Overall, the VOSCs obtained had δ34S values similar to the bulk kerogen values (mostly within 4‰). However, thiol (or mercaptan) δ34S values closely followed those of H2S (Δ34Sthiols-H2S = -1±1‰) throughout the experiment. Quantum chemistry calculations (ab-initio) for the S isotopic exchange between H2S and thiols were close to the experimental observations. This suggests that thiols rapidly attained equilibrium with H2S despite their very short residence time in the system (minutes to hours). Furthermore, throughout the experiment, the concentrations of the six different thiols were found to be proportional to the coexisting, concentration ratio of [H2]/[H2S]. The proportionality factors of the 6 different thiols strongly correlate with reported heats of formation (ΔHf°), further supporting the notion that the generation of thiols in the system rapidly reached equilibrium. At pyrolysis temperatures up to 350°C, δ34S and concentration values of other VOSCs produced in the gas phase, including sulfides and thiophenes, probably represent generation from S-containing moieties in kerogen and bitumen with limited interaction with co-existing H2S. The reaction of hydrocarbons and H2S to produce VOSCs is inversely correlated with thermal stability, i.e. thiols > sulfides > thiophenes. Therefore, the δ34S values, concentrations and distributions of VOSCs can be utilized as a proxy for reaction extent and formation mechanism of petroleum and H2S, including primary generation by thermal maturation, or potentially other processes such as migration and thermochemical sulfate reduction. This work demonstrates a novel and useful geochemical tool to study the source and fate of natural gas in the subsurface.

13211. 题目: Controls on volatile fatty acid concentrations in marine sediments (Baltic Sea)
文章编号: N19060711
期刊: Geochimica et Cosmochimica Acta
作者: Clemens Glombitza, Matthias Egger, Hans Røy, Bo Barker Jørgensen
更新时间: 2019-06-07
摘要: Volatile fatty acids (VFA) are key intermediates in the degradation pathway of organic matter (OM) in marine sediments. They are products of fermentation and are utilized as substrates in the terminal steps of microbial OM mineralization, such as sulfate reduction and methanogenesis. We studied the distribution of formate, acetate, propionate and butyrate concentrations in the pore water throughout 100-m deep sedimentary sequences in the Baltic Sea. The sediments included both sulfate and methane zones and were retrieved during the Integrated Ocean Drilling Program Expedition 347. VFA concentrations were consistently low throughout the sulfate and methane zones, ranging from few hundred nanomolar to about hundred micromolar, thus pointing to efficient microbial utilization in the terminal OM mineralization steps in both zones. Concentrations of formate followed a different depth trend than the other three VFAs suggesting a different mechanistical control of the formate turnover. Calculations of the Gibbs energy reveal that acetoclastic methanogenesis is exergonic (up to -30 kJ (mol CH4)-1) throughout the sulfate zone and suggest that methanogens can potentially coexist with sulfate reducers in the sulfate zone while sharing acetate as a substrate. In the deeper methane rich sediments, the energy yield of acetoclastic methanogenesis is generally very low (less negative than -10 kJ (mol CH4)-1). The uniformly low acetate concentrations in the methane zone suggest its active microbial turnover but the pathway from acetate to methane still remains unclear. Interestingly, acetoclastic sulfate reduction still yields at least -20 kJ (mol sulfate)-1 in the methane zone and, thus, sulfate reducers may utilize acetate as electron donor in the methane zone, which is in agreement with the earlier findings of sulfate reducers in methanogenic sediments.

13212. 题目: Linking chromophoric organic matter transformation with biomarker indices in a marine phytoplankton growth and degradation experiment
文章编号: N19060710
期刊: Marine Chemistry
作者: Michael R. Shields, Thomas S. Bianchi, Christopher L. Osburn, Joanna D. Kinsey, Kai Ziervogel, Astrid Schnetzer, Gabrielle Corradino
更新时间: 2019-06-07
摘要: The production and transformation of marine chromophoric dissolved organic matter (CDOM) provides a window into the marine biological pump as it is present at all depths and can be measured both in the field and via satellite. However, outside of lignin for terrestrial DOM, few studies have linked marine CDOM characteristics with biomarker indices. In this study, we quantified five fluorescent components of marine CDOM and base-extractable particulate organic matter (BEPOM) in a growth and degradation experiment using a natural plankton assemblage, and compared those results to bacterial abundances, hydrolytic enzyme activities, and amino acid concentrations and associated diagenetic indices. Rotating glass bottles containing plankton were sampled initially (day 0), during the mid-exponential (day 13) and stationary (day 20) growth phases, and again following a dark degradation period that lasted 42 days. Protein-like fluorescence (tryptophan-like and tyrosine-like) was correlated with the total amino acid concentrations for both the DOM and BEPOM through all phases of the incubation. However, tryptophan-like fluorescence showed a stronger correlation for aromatic amino acids. The concentration of particulate organic carbon changed significantly during each phase of the experiment and this substrate correlated with hydrolytic enzyme activities and bacterial abundance. This heterotrophy diagenetically altered the POM during the stationary phase and ultimately resulted in the increased production of more humic-like CDOM after degradation in the dark. Results from this study indicate that CDOM formation and cycling may play a prominent role in the ocean's nitrogen cycle.

13213. 题目: A mechanistic model of photochemical transformation and degradation of colored dissolved organic matter
文章编号: N19060709
期刊: Marine Chemistry
作者: J. Blake Clark, Patrick Neale, Maria Tzortziou, Fang Cao, Raleigh R. Hood
更新时间: 2019-06-07
摘要: Photochemical degradation (PD) of colored dissolved organic matter (CDOM) is a key transformational process for both natural and anthropogenic DOM. A fully mechanistic model is presented that can simulate laboratory incubations of the controlled PD of marsh and estuarine derived CDOM. The model was designed and optimized to recreate the loss of absorbance for marsh low tide and estuarine samples, representing high molecular weight allochthonous and mid molecular weight estuarine CDOM. In the model, high specific absorbance fractions representative of marsh and estuarine CDOM are transformed into a low specific absorbance fraction representative of coastal ocean CDOM as well as non-colored fractions. The various transformations in the model have maximum apparent quantum yields (at 284 nm) that range from 3.22 × 10−8 ± 1.75 to 56.05 ± 21.5 [mmol C (mol photons)−1], with non-colored DOM/inorganic carbon production outpaced by inter-molecular organic carbon transformations. Model performance was tested using an independent incubation data set whereby experimental results of photobleaching of spectral absorbance at 300 nm were recreated with a Willmott model skill of 0.98 and mean percent error of −3.66%. The production of the low molecular weight photodegraded end member ranged from 0.52 to 4.86 μmol C L−1 h1.
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13214. 题目: Black carbon in a glacier and snow cover on the northeastern Tibetan Plateau: Concentrations, radiative forcing and potential source from local topsoil
文章编号: N19060708
期刊: Science of The Total Environment
作者: Yang Li, Shichang Kang, Jizu Chen, Zhaofu Hu, Kun Wang, Rukumesh Paudyal, Jingshi Liu, Xiaoxiang Wang, Xiang Qin, Mika Sillanpää
更新时间: 2019-06-07
摘要: Black carbon (BC), which consists of the strongest light-absorbing particles (LAP) in snow/ice, has been regarded as a potential factor accelerating the melting of glaciers and snow cover over the Third Pole. During the winter and summer of 2016, snow, ice and topsoil were sampled from the Laohugou basin located on the northeastern Tibetan Plateau. Concentrations of BC in Laohugou Glacier No. 12 (LG12) and snow cover in this basin (LSC) varied broadly (21.7–2700.1 and 89.6 to 6326.2 ng g−1, respectively), indicating large spatiotemporal variability in wet, dry and post depositional conditions. Further, internally mixed BC in snow grains enhanced the albedo reduction (15.0–26.3%) more than externally mixed BC in LG12 and LSC. Dust played a more important role than BC in accelerating the melting of LG12, whereas these components played comparable roles in accelerating the melting of LSC. In total, externally mixed BC and dust reduced the albedo by 0.075–0.423, with an associated mean radiative forcing (RF) of 97.5 ± 41.5 Wm−2 in LSC. This level was lower than those in the ablation zone (354.1 ± 81.2 Wm−2) and accumulation zone (145.6 ± 76.7 Wm−2) of LG12 because of discrepancies in LAP concentrations, solar zenith angles and incoming shortwave radiation. Furthermore, we observed that topsoil containing abundant BC was transported along the slope from the debris to the LG12 surface ice, and topsoil in this region could be lifted by strong mountain-valley winds and then deposited on snow/ice surfaces, which affected the LAP concentrations. Therefore, this study is important for understanding the role of BC and dust in the melting of snow/ice in the northeastern Tibetan Plateau.
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13215. 题目: Variations of physical and chemical properties in relation to erythromycin mycelial dreg dewaterability under heat-activated persulfate oxidation conditioning
文章编号: N19060707
期刊: Science of The Total Environment
作者: Yanxiang Zhang, Huiling Liu, Xiaohu Dai, Chen Cai, Jing Wang, Yunpeng Shen, Peng Wang
更新时间: 2019-06-07
摘要: Erythromycin mycelial dreg (EMD) resulting from erythromycin (ERY) production process may be used as a nutrient resource. However, it has a high moisture content, which makes handling operations complicated. In this study, the EMD dewaterability under heat-activated persulfate (PS) oxidation conditioning was investigated. The variations of physical and chemical properties of EMD were further investigated to uncover the underlying mechanism of EMD dewaterability. Results indicated that EMD dewaterability was worse under single heat process, but significantly improved under heat-activated PS oxidation process. Heat-activated PS oxidation conditioning was capable to increase zeta potential, reduce median particle size, alter EMD flocs morphology, and disrupt mycelial cells. Concurrently, heat-activated PS oxidation conditioning resulted in the decrease of protein in tightly bound (TB) extracellular polymeric substances (EPS) and total EPS, and the decrease of fluorescing constituents (tryptophan protein, tyrosine protein and tryptophan amino acid) in EPS. Furthermore, a possible mechanism was proposed for heat-activated PS oxidation conditioning.

13216. 题目: High-resolution three-dimensional mapping of soil organic carbon in China: Effects of SoilGrids products on national modeling
文章编号: N19060706
期刊: Science of The Total Environment
作者: Zongzheng Liang, Songchao Chen, Yuanyuan Yang, Yue Zhou, Zhou Shi
更新时间: 2019-06-07
摘要: Soil organic carbon (SOC) is a key factor in soil fertility and structure and plays an important role in the global carbon cycle. However, SOC causes a large uncertainty in Earth System Models for predicting future climate change. The GlobalSoilMap (GSM) project aims to provide global digital soil maps of primary functional soil properties at six standard depth intervals (0–5, 5–15, 15–30, 30–60, 60–100, and 100–200 cm) with a grid resolution of 90 × 90 m. Currently, few SOC national products that meet the GSM specifications are available. This study describes the three-dimensional spatial modeling of SOC maps according to GSM specifications. We used 5982 soil profiles collected during the Second National Soil Survey of China, along with 16 environmental covariates related to soil formation. The results were obtained by parallel computing over tiles of 100 × 100 km, and the predictions for the tiles were subsequently merged into a single SOC map for the whole of China per standard GSM depth interval. For each standard GSM depth interval, SOC contents and their uncertainties were predicted and mapped at a spatial resolution of approximately 90 m using bootstrapping. Southwestern and northeastern China had higher SOC contents than the rest of China did, whereas northwestern China had a lower SOC content. The range of the coefficient of determination for the six depth intervals ranged from 0.35 to 0.02, and the mean SOC content was 17.86–8.67 g kg−1. Both these values decreased strongly with increasing soil depth. Cropland SOC content was lower than that of forest and grassland. The results of variable importance show that SoilGrids data were the best predictors for defining the soil-landscape relationship during regression modeling for SOC. These SOC maps can provide a data source for environmental modeling, a benchmark against which to evaluate and monitor SOC dynamics, and a guide for the design of future soil surveys.
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13217. 题目: Effective removal by coagulation of contaminants in concentrated leachate from municipal solid waste incineration power plants
文章编号: N19060705
期刊: Science of The Total Environment
作者: Xu Ren, Ximeng Xu, Yu Xiao, Weiming Chen, Kai Song
更新时间: 2019-06-07
摘要: Municipal solid waste (MSW) incineration is widely used in China. Concentrated leachate, containing high concentrations of pollutants, is an important type of secondary pollution produced in MSW incineration power plants and requires proper treatment. In this study, various coagulants were used to treat concentrated leachate from a nanofiltration (NF) membrane that treated leachate from an MSW incineration plant. The optimal coagulation condition was determined in this study. Under the optimal condition, removals of chemical oxygen demand, light absorbing substances (at 254 nm), total nitrogen, color and turbidity were 68.42%, 69.01%, 44.14%, 92.31% and 87.44%, respectively. Much of the refractory organic matter with relatively high molecular weight, aromaticity and humification degree was removed, and effluent had a lower molecular weight than raw NF concentrated leachate. Study also found that some parts of high molecular weight compounds from NF CL were removed by coagulation process, but the change of distribution of molecular weight was not outstanding. The NF concentrated leachate, both before and after coagulation, contained a large amount of chloride. Hence, a follow-up study should be conducted to find an effective additional processing that can remove organic matter using the high concentration of chloride in the NF concentrated leachate coagulation effluent. This study provides a theoretical basis for the treatment of concentrated leachate from MSW incineration power plants.
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13218. 题目: Comparing three Australian natural organic matter isolates to the Suwannee river standard: Reactivity, disinfection by-product yield, and removal by drinking water treatments
文章编号: N19060704
期刊: Science of The Total Environment
作者: Kalinda Watson, Maria José Farré, Nicole Knight
更新时间: 2019-06-07
摘要: Water treatments that provide efficient removal of organic and inorganic disinfection by-product (DBP) precursors across variable natural organic matter (NOM) sources are desirable. Treatments that effectively remove inorganic DBP precursors such as bromide, which significantly shift the speciation of DBP formation towards more toxic DBPs, are of particular interest and have been less investigated.This study characterised NOM isolated from three major drinking water sources in Southeast Queensland (SEQ), Australia, and compared it to the International Humic Substances Society (IHSS) Suwannee River NOM isolate (SR) in terms of DBP precursor removal treatments and DBP formation. Each NOM isolate was used to make synthetic water samples with otherwise identical water quality parameters, that were treated with enhanced coagulation (EC) or EC followed by; anion exchange (MIEX® resin), powdered activated carbon (PAC), granular activated carbon (GAC) or silver impregnated activated carbon (SIAC), to investigate the removal of DBP precursors (bromide and DOC), minimisation of DBPs, as well as the change in specific chlorine demand. EC/SIAC treatment was the most effective method of DBP control studied, due to the efficient simultaneous NOM and bromide adsorption of the SIAC (99 ± 1% bromide removal regardless of NOM source). This treatment also resulted in >92% removal of each of the measured DBPs across all NOM sources, with the exception of DBAN and 1,1-DCP, which achieved >80% removal across all NOM sources. Increases in tribromomethane (TBM) and dibromoacetonitrile (DBAN) formation were observed after all other treatment/NOM-isolate combinations, due to increased Br:DOC ratio after treatment, whereas chlorinated DBPs were generally well-controlled by all treatment/NOM-isolate combinations. Differences in reactivity of the individual NOM isolates were found to be related to both the origin of the isolate and the treatment employed, however, bromide removal capacity for each treatment was independent of NOM source.
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13219. 题目: Post-agricultural restoration: Implications for dynamics of soil organic matter pools
文章编号: N19060703
期刊: CATENA
作者: Olga Kalinina, Alexander Cherkinsky, Oleg Chertov, Sergey Goryachkin, Irina Kurganova, Valentin Lopes de Gerenyu, Dmitry Lyuri, Yakov Kuzyakov, Luise Giani
更新时间: 2019-06-07
摘要: In order to bridge the gap of knowledge in respect of soil organic matter (SOM) dynamics of post-agricultural Luvisols during restoration, the study focused on alteration processes of functionally different SOM pools, 14C ages, and C turnover rates in a chronosequential approach. The study comprises three Luvisol chronosequences of 37 years (North), 120 years (Middle), and 42 years (South) across a climate gradient of the temperate broad-leaved forests of European Russia. Restoration led to SOM accumulation within both active (free particulate organic matter (POM) and occluded POM and passive (clay fraction) pools, and as a result, in gains of total organic carbon (C). Accumulation of new C was confirmed by increasing ∆14C signatures of occluded POM and clay fractions. After 22 years of restoration, ∆14C signatures progressed from negative to positive values for the occluded POM fraction, whereas they showed a similar development but remained negative for the clay faction. This highlights the fact that the incorporation of new C into the passive pool takes place, but that it occurs at a slower rate compared to that of the active pool. The 14C age of occluded POM fraction declined from 600 to 1200 years before present (BP) in arable sites to about 200 years BP after 22 years of restoration and thereafter. The 14C age of the clay fraction decreased from 1670 to 2660 years BP in arable soils to 750 years BP in 22 year abandoned site, 450–310 years BP in 32–66 year abandoned sites, and 200–370 years BP in near-natural forests. This decline of the 14C age reveals a change of the proportions between old and young C within the passive pool caused by management and the development of an ecosystem towards a steady state. Recovery of C was accompanied by initially increasing and then decreasing turnover rates of SOM, both again, much more pronounced in the active pool. These dynamics trace an initial ecosystem disturbance after abandonment, which slows down with time. Although C recovery and adjusted turnover rates of SOM progressed towards a new steady state of ecosystem; full restoration was not achieved within the chronosequential time scale of 120 years.

13220. 题目: Soil organic carbon density and its driving factors in forest ecosystems across a northwestern province in China
文章编号: N19060702
期刊: Geoderma
作者: Jin-Hong Guan, Lei Deng, Jian-Guo Zhang, Qiu-Yue He, Wei-Yu Shi, Guoqing Li, Sheng Du
更新时间: 2019-06-07
摘要: Forest soils are an important component of the global carbon cycle, as they sequester and store much more organic carbon than other terrestrial ecosystems. Thus, reliable information on the forest soil organic carbon (SOC), along with the factors that influence it, is crucial from the perspective of regional carbon budgets and climate modeling. Gansu Province in northwestern China is characterized by complex climatic gradients and diverse forest types, suggesting a large variability in the spatial distribution of SOC, yet the SOC stock in this region has not been comprehensively investigated because of insufficient soil profile data. Our study covered the entire forest area in the province via a regional-scale sampling campaign, and provided soil organic carbon density (SOCD) data obtained from 112 natural forests and 100 plantations. Influencing factors including forest type, forest stand age, soil type, litter carbon, climate, and topography were evaluated in both natural forests and plantations. The results indicated a SOC stock of 433.4 ± 13.2 Tg C and a SOCD value of 175.3 ± 33.0 Mg C ha−1 for the 0–100 cm layer at the regional scale. Specifically, the SOC stock and the forest area-weighted average SOCD in natural forests were estimated at 349.0 ± 16.5 Tg C and 207.3 ± 23.2 Mg C ha−1, which were about quadruple and double, respectively, of the values for the plantations. Regardless of natural forests and plantations, SOCD increased with both stand age class and elevation and decreased with mean annual temperature (MAT). SOCD also increased with mean annual precipitation (MAP) for natural forests with elevation <2500 m and for all plantations. The overall importance to SOCD of the explanatory variables increased with increasing soil depth in natural forests while decreased with increasing soil depth in plantations. Forest type, stand age, soil type, MAT, MAP, elevation, litter carbon, slope, and aspect explained 58 and 65% of the total variation in the SOCD at 100 cm depth in natural forests and plantations, respectively. In natural forests, the most important explanatory variable for the uppermost 30 cm was soil type, while it was MAT for the whole 100 cm; in plantations, the most prominent factors were forest type and elevation, regardless of the soil depth. These suggest that environmental changes will likely have different effects on SOCD in natural forests and plantations.

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