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25201. 题目: Organic matter accumulation in the Upper Devonian Duvernay Formation, Western Canada Sedimentary Basin, from sequence stratigraphic analysis and geochemical proxies
文章编号: N18092710
期刊: Sedimentary Geology
作者: Nicholas B. Harris, Julia M. McMillan, Levi J. Knapp, Maria Mastalerz
更新时间: 2018-09-27
摘要: We present a model for organic carbon accumulation in the Upper Devonian Duvernay Formation of the Western Canada Sedimentary Basin, relating total organic carbon (TOC) concentrations to a high resolution geochemical and organic petrologic database and comparing these to a core-based sequence stratigraphic interpretation. Many previous source rock studies have suggested that organic matter is enriched in transgressive systems tracts or at maximum flooding surfaces, an observation that is commonly attributed to an assumed relationship between water depth and oxygen levels. Our data set enables us to associate total organic matter content and organic assemblages with particular systems tracts and to examine how the organic assemblages change across the basin, tested against proxies for redox conditions and bioproductivity to relate relative sea level to specific mechanisms for organic accumulation. The Duvernay Formation comprises three third-order depositional sequences, superimposed on a second-order late transgressive systems tract and early highstand systems tract. Sequences are composed almost entirely of transgressive systems tracts and highstand systems tracts, with a lowstand systems tract only at the base of the upper cycle that marks the second-order sea level turnaround. Depositional facies generally vary from bioturbated carbonate-rich siltstones to siliceous mudstones from the platform margins to basin center. Organic petrologic analysis records predominantly amorphous organic matter and solid bitumen, with much less abundant vitrinite and inertinite. Organic matter type indicated by Rock-Eval analysis shows that in most cases, high total organic carbon (TOC) content is associated with better quality organic matter (high hydrogen index) and vice versa, indicating more reducing conditions or higher bioproductivity were responsibility for organic enrichment. However, near carbonate reefs, hydrogen index is uncorrelated with TOC, indicating that here, dilution by carbonate minerals was the primary control on organic enrichment. Across most of the basin, highest TOCs are recorded just above the second-order maximum flooding surface. Secondary peaks in TOC are recorded above the maximum flooding surface in the upper third-order cycle and in the transgressive systems tract of lower third-order cycle. Low TOC values are recorded in the lowstand systems tract and in the middle and upper third-order transgressive systems tracts almost up to the maximum flooding surfaces.Throughout much of the basin, proxies for relative sea level, restriction of water masses (Mo/TOC), redox conditions (Mo/Al and S/Fe) and bioproductivity (biogenic silica) coincide. These relationships demonstrate that organic carbon accumulation resulted from influxes of nutrient-rich upwelled water during high sea level; thus, TOC values are highest in the upper part of transgressive systems tracts and lower highstand systems tracts. Anoxia typically developed as a result of bioproductivity and enhanced organic matter accumulation but was not itself a trigger for organic sedimentation. Near carbonate reefs, however, varying sea level regulated carbonate sedimentation rate and organic matter dilution, and bioproductivity had less impact on organic matter concentrations; thus, TOC was high when carbonate deposition was low during transgressions, which forced carbonate reefs to backstep, limiting carbonate sedimentation in deeper water area.

25202. 题目: Diversity of nitrogen fixing bacterial communities in the coastal sediments of southeastern Arabian Sea (SEAS)
文章编号: N18092709
期刊: Deep Sea Research Part II: Topical Studies in Oceanography
作者: Thajudeen Jabir, Yousuf Jesmi, Puthiya Veettil Vipindas, Mohamed Hatha AA
更新时间: 2018-09-27
摘要: The present study depicts diversity, abundance and activity of nitrogen (N₂) fixing bacterial communities in the coastal sediments of southeastern Arabian Sea (SEAS). The diversity of N₂ fixing bacterial community was determined by clone library analysis of nifH gene, the culturable N₂ fixing bacteria was determined by 16s rRNA and nifH gene analysis. The nitrogen fixation rate in the sediments was also estimated by acetylene reduction assay method. The nifH clone library analysis revealed that fifteen putative diazotrophs, belonging to alpha-, beta-, gamma-, delta-, epsilon- Proteobacteria and Firmicutes. The predominant operational taxonomic units (OTUs) among these were related to α-Proteobacteria (with 16% of total sequences); β-Proteobacteria (10% sequences); γ-Proteobacteria (29% sequences); δ-Proteobacteria (11% sequences); ε-Proteobacteria (21% sequences); Firmicutes (3% of sequences) and percent of some sequences remained unknown. The 16s rRNA gene based identification of culturable N₂ fixing bacteria revealed the presence of seven nitrogen fixing bacterial species namely Acinetobacter johnsonii, Rhizobium rosettiformans, Bacillus megaterium, B. circulans, B. flexus, B. oceanisediminis and B. subtilis. The observed N₂ fixation rate in the sediments ranged from 0.12 to 0.36 nmol N g⁻¹ h⁻¹. Canonical correspondence analysis (CCA) revealed significant influence of the environmental variables such as sediment type, total nitrogen (TN), total organic matter (TOM), total organic carbon (TOC), iron (Fe), manganese (Mn), total sulphur (TS), nitrite (NO₂) and nitrate (NO₃) on the diversity of N₂ fixing bacteria and N₂ fixation rate. The observations of the current study provide a better understanding of N₂ cycling in coastal sediments of the SEAS and sources of fixed nitrogen.

25203. 题目: Predator-induced changes in dissolved organic carbon dynamics
文章编号: N18092708
期刊: Oikos
作者: Romana Limberger, Julia Birtel, Hannes Peter, Núria Catalán, Daniel da Silva Farias, Rebecca J Best, Jakob Brodersen, Helmut Bürgmann, Blake Matthews
更新时间: 2018-09-27
摘要: The fate of dissolved organic carbon (DOC) is partly determined by its availability to microbial degradation. Organisms at upper trophic levels could influence the bioavailability of DOC via cascading effects on primary producers and bacteria. Here we experimentally tested whether the presence of fish in aquatic food webs can indirectly affect the composition of the DOC pool. We found that fish had strong positive effects on phytoplankton biomass that affected the dynamics of DOC composition. Specifically, fish increased protein-like, algae-derived DOC mid-experiment, concurrent with the strongest fish-induced increase in phytoplankton biomass. Fish also increased bacterial abundance, altered the community composition and diversity of bacteria, and temporarily increased DOC compounds with fluorescence properties indicative of microbially-reprocessed organic matter. Overall, our experiment revealed that fish can positively influence the substrate (algae-produced DOC) and the key players (bacteria) of the microbial carbon pump. Consequently, fish could contribute to carbon sequestration by stimulating both the production of bioavailable DOC and the microbial degradation of bioavailable to persistent DOC. We propose this as a novel mechanism whereby the loss of predators from global ecosystems could alter carbon cycling. This article is protected by copyright. All rights reserved.

25204. 题目: Carbonaceous components and major ions in PM10 from the Amazonian Basin
文章编号: N18092707
期刊: Atmospheric Research
作者: Danilo Custodio, Célia Alves, Yendry Jomolca, Pérola de Castro Vasconcellos
更新时间: 2018-09-27
摘要: Air pollution mainly resulting from deforestation and agricultural activities has become one of the major concerns in the Amazonian Basin. A detailed analysis of the PM₁₀ chemical composition is critical for devising pollution control measures and improving climate models. In this study, daily 24-h filter samples were collected and analyzed in different sites of the Amazon Basin between 2008 and 2016 (over 200 samples). The six sampling sites were classified into two groups, one in South Amazonia, a region with strong influence of land occupation, and another in a remote forest region to the North. The high mean concentrations of PM₁₀ and the occurrences of extreme events at the Southern site denote air pollution episodes. High correlations between the temporal trends of PM₁₀ and primary species linked to soil re-suspension and biomass burning highlight the contribution of these sources of air pollution in the region. Significant differences between PM₁₀ in the South and North regions were observed, for which levels of 72.6 ± 66.5 μg m⁻³ and 8.9 ± 4.2 μg m⁻³, respectively. The average concentrations of organic carbon (OC) and elemental carbon (EC) in the aerosol were 5.81 ± 4.18 μg m⁻³, 2.43 ± 1.65 μg m⁻³ and 5.17 ± 5.54 μg m⁻³, 0.51 ± 0.41 μg m⁻³, respectively, for the Southern and Northern Amazonia sampling sites. The aerosol was largely composed of inorganic species in Southern Amazonia, whose carbonaceous matter accounted for 16% of the gravimetrically measured PM₁₀. However, in the forest region, the contribution of carbonaceous species, mainly OC, accounted for >90% and remained more constant throughout the seasons. Na⁺ was the dominant water soluble ion in samples from the Southern region, followed by SO₄⁻², NO₃⁻, Ca²⁺ and K⁺. High levels of carbonate (CC) were also observed for these samples. For the Northern region, SO₄⁻² was the dominant soluble ion, followed by K⁺ and NH₄⁺. Some of these species exhibited a clear seasonal trend during the study period. This study provides a better understanding of the current state of air pollution in diversified Amazon basin sites.

25205. 题目: Resilience of benthic ecosystem C-cycling to future changes in dissolved oxygen availability
文章编号: N18092706
期刊: Deep Sea Research Part II: Topical Studies in Oceanography
作者: Carol M White, Clare Woulds, Greg L Cowie, Andrew Stott, Hiroshi Kitazato
更新时间: 2018-09-27
摘要: In marine sediments, the availability, cycling and burial of organic carbon (OC), the size and composition of the faunal community, and the availability of dissolved oxygen (DO) are closely coupled. In light of expected expansions in marine hypoxia and of oxygen minimum zones (OMZs) in particular, it is now necessary to de-convolve DO from the frequently co-varying factors OC concentration and faunal biomass, in order to understand the effect of changing dissolved oxygen (DO) concentrations on the magnitude and pattern of biological processing of organic carbon (OC). This is especially important on the continental slope, a significant location for C cycling and burial.In this study, stable isotope tracer experiments were conducted at three sites with contrasting ambient DO concentrations of 0.5, 2.8 and 21.2 μM (at depths of 530m, 812m and 1140m respectively) on the Indian continental margin. Experiments were conducted both at ambient DO concentrations, and also, for the first time, under manipulated DO concentrations both 5% above and below ambient. The ¹³C label was added as algal detritus, and traced through the processes of respiration, and uptake into bacterial biomass, and into metazoans and foraminifera.Total C biological processing under ambient DO conditions was similar across all three sites, suggesting that benthic communities are well adapted to local conditions, such that OC processing is optimised even at severely hypoxic sites.DO manipulation produced changes in the pattern of OC processing by the benthic community. Oxygen manipulations in both directions resulted in decreases in total community respiration, except at the most hypoxic site. Bacterial uptake, in contrast, increased in response to all DO manipulations. Faunal ¹³C uptake tended to increase with increased DO. At the most hypoxic site (0.5 μM) this was attributable to increased foraminiferal activity, whereas at the most oxygenated site (21.2 μM) it was the metazoans that showed increased biomass-specific ¹³C uptake. Similarly, decreases in DO tended to reduce faunal ¹³C uptake, with metazoans disproportionately affected where they were already living at the lower end of their DO tolerance (i.e. 2.8 μM). Thus, the taxa most affected by DO manipulation depended on antecedent DO conditions. The total capacity of the benthic community to process freshly deposited OC (i.e. respiration plus uptake by bacterial and different fauna) increased following upwards manipulation of DO at the 0.5 μM site, but was not adversely affected by downwards manipulation of DO. Thus, results suggest that benthic communities possess some functional resilience, and that future expansion of marine hypoxia, while impacting benthic ecosystem structure, may not have as marked an effect on biological C processing.

25206. 题目: Comparative effect of compost and technosol enhanced with biochar on the fertility of a degraded soil
文章编号: N18092705
期刊: Environmental Monitoring and Assessment
作者: Rubén Forján, Alfonso Rodríguez-Vila, Beatriz Cerqueira, Emma F. Covelo, Purificación Marcet, Verónica Asensio
更新时间: 2018-09-27
摘要: A large number of studies on the reclamation of mine soils focused on the problem caused by metals and did not explore in depth the issue of nutrients and vegetation after the application of organic materials. The aim of this study was to compare the effect of two treatments made of wastes and vegetated with Brassica juncea L. on the fertility of a settling pond mine soil. The first treatment was compost, biochar, and B. juncea (SCBP) and the second treatment was technosol, biochar, and B. juncea (STBP). This study evaluated the effect of the treatments on the soil nutrient concentrations and fertility conditions in the soil amendment mixtures, after 11 months of greenhouse experiment. Total carbon and nitrogen concentrations were higher in treatment SCBP than in treatment STBP after 7 months but, after 11 months, carbon concentration was higher in STBP. The used technosol could have forms of carbon more stable than compost, which could be released slower than in the compost-amended soils. Both compost and technosol mixed with biochar also increased the concentration of calcium, potassium, magnesium, and sodium in exchangeable form in the mine soil.

25207. 题目: Degradation of organic contaminants through activating bisulfite by cerium(IV): A sulfate radical-predominant oxidation process
文章编号: N18092704
期刊: Chemical Engineering Journal
作者: Hongyu Dong, Jie Chen, Liying Feng, Weixian Zhang, Xiaohong Guan, Timothy J. Strathmann
更新时间: 2018-09-27
摘要: In this study, the activation of bisulfite by cerium(IV) (Ce(IV)/HSO₃⁻ process) is proposed for the first time to degrade organic contaminants. Experiments show that carbamazepine (CBZ), a representative recalcitrant contaminant of emerging concern, is oxidized by Ce(IV)/HSO₃⁻ treatment at pH_ini 3.0–7.0 when O_2(aq) is present to promote HSO₃⁻ autoxidation. SO₄⁻, HO, and SO₅⁻ were identified as active oxidants of CBZ based on the ESR spectra and the results of alcohol quenching experiments. Quantitative analysis indicates that SO₄⁻ plays a major role, while HO and other species play minor roles in the degradation of CBZ in the Ce(IV)/HSO₃⁻ process. SO₄⁻ radicals are derived from the reaction of SO₅⁻ with HSO₃⁻ and the activation of hydrogen peroxomonosulfate (HSO₅⁻) by Ce(IV). Five degradation pathways of CBZ are proposed based on transformation products identified by UPLC-QToF-MS/MS, and proposed sites for radical attack are supported by the results of frontier electron density calculations. Elevated concentrations of Cl⁻, Fe(III), and humic acid (HA) inhibit CBZ degradation, while other non-target solutes have minimal effects on CBZ degradation in the Ce(IV)/HSO₃⁻ process. Finally, experiments demonstrating degradation of a suite of other organic contaminants suggests that the Ce(IV)/HSO₃⁻ system can be applied as a new advanced oxidation process for wastewater treatment.
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25208. 题目: Evaluation of chemical extractants to assess metals phytoavailability in Brazilian municipal solid waste composts
文章编号: N18092703
期刊: Environmental Pollution
作者: Verónica Asensio, Cassio H. Abreu-Junior, Fábio César da Silva, José Carlos Chitolina
更新时间: 2018-09-27
摘要: Municipal solid wastes (MSW) can be composted to become an organic fertilizer. However, besides plant nutrients, it can also contain high concentration of some toxic metals than can pollute agricultural soils, contaminate food, animals and human being. A greenhouse experiment was carried out for two purposes: i) to evaluate the concentrations of cadmium, copper, chromium, nickel, lead and zinc in four Brazilian MSW composts, and, ii) to know which is the best solution for extracting those metals in phytoavailable form from the composts. In order to evaluate the phytoavailability of metals, they were extracted with six chemical extractants: i) water, ii) 0.05 mol L⁻¹ Ca(NO₃)₂, iii) 0.1 mol L⁻¹ HCl, iv) 0.005 mol L⁻¹ DTPA at pH 7.3, v) 0.05 mol L⁻¹ CaCl₂ and vi) Mehlich 3 solution. In addition, lettuces were cultivated as a test plant in pots containing 1.8 kg of MSW compost as substrate. Fifty-six days later, lettuce plants were harvested. New lettuces were then planted for a second cycle, and then harvested after fifty-six days. Semi-total concentration of metals in composts and total in plants was also determined through an extraction with nitric-perchloric acid. Semi–total concentration of Cd and Pb exceeded the intervention limits from Brazil in the four studied composts, and lettuce plants were polluted by those two elements. Therefore, compost made of MSW must be characterized before being used for agricultural soils. Copper and nickel in phytoavailable were effectively extracted with the strongest chelating agents used, HCl and Mehlich 3, probably because most metal is bound to organic matter in the compost. Cadmium, chromium, lead and zinc were no efficiently extracted with any of the tested extractants.
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25209. 题目: Biochar application alleviates unbalanced nutrient uptake caused by N deposition in Torreya grandis trees and seedlings
文章编号: N18092702
期刊: Forest Ecology and Management
作者: Rui Zhang, Yuxin Zhao, Jianhong Lin, Yuanyuan Hu, Heikki Hänninen, Jiasheng Wu
更新时间: 2018-09-27
摘要: Foliar nitrogen: phosphorus (N:P) ratio is a valuable indicator of nutrient limitation in forest ecosystems. The ratio is currently dramatically affected by the increasing anthropogenic N deposition in China. Biochar, a soil amendment, has profound benefits for improving soil N and P availability. However, little is known about N and P uptake and nutrient balance of plants growing on biochar-amended soils under N deposition. Here, we conducted a two-year N addition and biochar application factorial experiment with Torreya grandis trees and seedlings, and the responses of concentrations of foliar N and P and the foliar N:P ratio were evaluated. N addition alone increased foliar N concentration, but did not change foliar P concentration, and thus increased foliar N:P ratio. Biochar application alone increased concentrations of both foliar N and P but did not cause any change in the N:P ratio. Most importantly, when applying N and biochar together, the concentration of foliar P increased and the foliar N:P ratio decreased, relative to each N treatment alone. This novel result suggests that biochar application can serve as an effective forest management tool, which can not only enhance the availability of N and P nutrients, but also alleviate the imbalanced uptake of nutrients indicated by the high foliar N:P ratios under increasing N deposition.

25210. 题目: Understanding the potential for selective natural organic matter removal by ion exchange
文章编号: N18092701
期刊: Water Research
作者: P. Finkbeiner, J. Redman, V. Patriarca, G. Moore, B. Jefferson, P. Jarvis
更新时间: 2018-09-27
摘要: Dissolved organic carbon (DOC) removal from a river water source was investigated using ion exchange (IEX), coagulation and membrane filtration. This research linked the variable charge characteristics of the organic compounds present in the source water with removal by IEX and coagulation. The raw water charge density fluctuated considerably (between 5.4 to 10.7 meq mg_DOC^-1) and controlled removal of the charge loading. Importantly, charge density was not correlated with the organic carbon concentration. The combined IEX and coagulation process reduced the specific DBP-FP (sDBP-FP) of the final water, with values as low as 18 μg mg_DOC^-1 for both haloacetic acids and trihalomethanes. IEX removed a particular fraction of NOM that 1) enhanced coagulation efficiency, providing increased removal of overall DOC; and 2) enabled coagulation to subsequently remove higher levels of specific components of NOM that have a high DBP-FP. The component of NOM removed by IEX that had a positive impact on coagulation was identified to be charged low molecular weight organic compounds of all hydrophobicity levels, resulting in a reduced specific DBP-FP compared to coagulation alone.
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25211. 题目: Different responses of soil organic carbon fractions to additions of nitrogen
文章编号: N18092614
期刊: European Journal of Soil Science
作者: H. Chen, D. Li, W. Feng, S. Niu, A. Plante, Y. Luo, K. Wang
更新时间: 2018-09-26
摘要: Carbon–nitrogen (C–N) interactions in terrestrial ecosystems regulate climate–C cycle feedbacks. How additions of N affect soil C sequestration and then regulate climate change, however, are not fully understood. Previous studies have assessed effects of N on bulk soil organic C (SOC) but have not yet carefully examined its effects on different SOC fractions, which determine how fast the N‐regulated C cycle feeds back to climate. Here we synthesized data from 36 studies with 296 observations by a meta‐analysis to evaluate the responses of SOC fractions to N additions. We hypothesized that additions of N might increase both labile and non‐labile C fractions. The SOC that was separated by density fractionation increased by 18.3% for free light fractions and by 3.0% for heavy density fractions without change in the occluded light fraction under N addition compared with the control. The SOC that was separated by aggregate fractionation increased by 4.4% for macroaggregate‐associated fractions and by 6.5% for aggregate mineral‐associated fractions without change in the microaggregate‐associated fraction under N additions. When bulk SOC was separated by chemical permanganate oxidation, the oxidizable fraction increased by 10.4%, whereas the unoxidizable fraction increased by 4.5%. The changes in different soil C fractions were related to the mechanisms of SOC stabilization. Because of the significant increases in non‐labile SOC fractions, our findings suggest that on a global scale, increased additions of N might promote SOC accumulation and slow down climate change in the long term. Our results will be useful in model development for better prediction of SOC sequestration under additions of N.

25212. 题目: A comparison study of in-situ coagulation and magnetic ion exchange (MIEX) as pre-treatments for ultrafiltration: Evaluating effectiveness of organic matters removals and fouling mitigation
文章编号: N18092613
期刊: Chemosphere
作者: Weiying Xu, Yingying Chen, Huikai Liang, Guoqing Sang, Dong Wei, Dongsheng Wang, Bin Du
更新时间: 2018-09-26
摘要: This work was designed to compare the effectiveness of in-situ coagulation and MIEX as pre-treatments prior to ultrafiltration (UF) to improve organic matter (OM) removal and mitigate membrane fouling. Three kinds of OMs, i.e. salicylic acid (SA), humic acid (HA) and bovine serum albumin (BSA) were employed. The experimental results show that coagulation-UF led to most effective removal of HA (almost 90%), while the SA was uncoagulated and least removable, with the rejection rate of about 55%. Conversely, MIEX present superior ability for removing SA, contributing to additional efficiency of 71.95–77.21% than UF alone. Proper dosage of Al-based coagulants could alleviate flux loss, especially in the cases of HA and BSA. Increasing coagulant dose resulted in continuous decrement of irreversible resistance (R_ir), which dominated the membrane fouling development by the SA water. For HA and BSA waters, alternatively, variations of R_r determined the flux declines. Floc compact degree was the decisive factor for R_r for coagulated SA; while for HA and BSA, R_r was most related to the floc size and foulant-foulant interaction. MIEX was most effective for alleviating flux loss when treating the hydrophilic SA with small molecules and for all the cases, MIEX exerted little influence on the R_r values.
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25213. 题目: Characterizing the roles of organic and inorganic foulants in RO membrane fouling development: The case of coal chemical wastewater treatment
文章编号: N18092612
期刊: Separation and Purification Technology
作者: Shu Wang, Kang Xiao, Xia Huang
更新时间: 2018-09-26
摘要: In this study, various fouling characteristics on the surface of a commercial reverse osmosis (RO) membrane were identified, in terms of different organic and inorganic components. Specifically, a practical secondary wastewater of coal chemical industry was used as the feed solution, and was fractionated into six hydrophobic/hydrophilic acid/base/neutral portions. RO membrane fouling behaviors at different stages were critically described using two characteristic parameters, i.e., initial flux decline rate and final steady-state flux. These parameters were quantified using Michaelis-Menten relation as a model fitting method. In general, the hydrophilic neutral (HIN) and hydrophobic neutral (HON) fractions had the fastest initial fouling rate and the lowest steady-state flux, mainly due to their high contents of polysaccharide. Among the organic constituents (polysaccharide/protein/humic acid), polysaccharide was the most responsible for rapid initial flux decline and low final steady-state flux, as proved by Kendall’s correlation. Among the inorganic constituents (Ca/Mg/Si), Si was found to exert the greatest influence on the final steady-state flux. This indicates that polysaccharide and Si played a combined role in determining the foulant layer permeability at the prolonged fouling stage, and a possible mechanism is that Si might alter the structure of polysaccharide gel layer. Further information on the fouling layers was systematically provided by means of Fourier transform infrared spectroscopy, confocal laser scanning microscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy with fractal dimension analysis.
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25214. 题目: Extracellular polymeric substances (EPS) modulate adsorption isotherms between biochar and 2,2′,4,4′-tetrabromodiphenyl ether
文章编号: N18092611
期刊: Chemosphere
作者: Guangxia Liu, Hongjie Sheng, Yuhao Fu, Yang Song, Marc Redmile-Gordon, Yan Qiao, Chenggang Gu, Leilei Xiang, Fang Wang
更新时间: 2018-09-26
摘要: Extracellular polymeric substances (EPS), chars and persistent organic pollutants (POPs) frequently coexist in the environment. However, a knowledge gap exists regarding their interactions. Therefore, we applied 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) as a model POP to investigate the influence of bovine serum albumin (BSA) and sodium alginate (SA) - representing protein and polysaccharide components of EPS - on POP adsorption to biochars. Surface activities of tested biochars were characterised using nuclear magnetic resonance, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The adsorption capacities of BDE-47 on biochars were significantly improved by both EPS analogues: BSA at concentrations of only 5 mg L⁻¹ and SA at 80 mg L⁻¹ at c_e = 1 S_w BDE-47 concentration. However, 80 mg L⁻¹ BSA decreased the BDE-47 adsorption capacities on biochars at the tested BDE-47 concentrations. Chemisorption and pore filling mechanisms appeared to dominate the adsorption process of BDE-47 on maize straw and wheat straw biochars. After adding BSA (or SA), a hydrophobic partition effect was found to best explain the adsorption process and linearity of adsorption was enhanced. These results progress our understanding of bioavailability and migration of POPs: especially relevant to the water industry and biochar/EPS facilitated removal of these contaminants.
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25215. 题目: Influence of physicochemical properties of various soil types on iodide and iodate sorption
文章编号: N18092610
期刊: Chemosphere
作者: Eva Duborská, Martin Urík, Marek Bujdoš, Michaela Matulová
更新时间: 2018-09-26
摘要: Studies that deal with iodine mobility in uncontaminated agricultural soils are scarce and unique. Therefore, in this article, we have evaluated the sorption behavior of two most abundant naturally occurring inorganic iodine species – iodide and iodate – in several soil types. Our results showed that the sorption process is extremely slow with equilibrium achieved after ten days. The sorption of both iodine species is well described by Freundlich isotherm. The affinity of iodine for all investigated soils in the observed concentration range is relatively low. Our results showed that besides iodine speciation, sorption efficiency is highly dependent on soil types and their characteristics. While in mineral soils with low organic carbon content iodide sorption is dominant, organic rich soils are more favorable for iodate sorption. Organic carbon, clay content, pH and the abundance of iron, aluminum and manganese oxides and hydroxides showed to be the most important soil properties controlling iodine sorption. Our results provide new insight into the complex iodine behavior and retention in soils. This is crucial for better understanding of iodine mobility and the ability to enter the food chain.

25216. 题目: Influence of algal organic matter on MS2 bacteriophage inactivation by ultraviolet irradiation at 220 nm and 254 nm
文章编号: N18092609
期刊: Chemosphere
作者: Yulin Wang, Elbashir Araud, Joanna L. Shisler, Thanh H. Nguyen, Baoling Yuan
更新时间: 2018-09-26
摘要: We determined the potential interference of extracellular algal organic matter (EAOM) and intracellular algal organic matter (IAOM) extracted from Microcystis aeruginosa on MS2 bacteriophage inactivation under UV irradiation at two wavelengths (220 and 254 nm). UV irradiation at 220 nm doubled the inactivation rate of MS2 in water containing EAOM than in organic-free phosphate buffered solution. In contrast, EAOM did not change MS2 inactivation by exposure to UV 254 nm. The presence of IAOM did not significantly influence MS2 inactivation by exposure to either UV 254 or UV 220 nm. To achieve 3 log₁₀ inactivation of MS2, UV254 nm required more than double the dose of UV220 nm (45 mJ/cm² vs. 20 mJ/cm²). Linear correlations between the reduction in infectivity and the reduction in genome copies detected by reverse transcription quantitative polymerase chain reaction suggested that genomic damage is the main mechanism responsible for MS2 inactivation in water containing algal organic matter (AOM) by exposure to UV irradiation. These findings suggest that the presence of AOM did not negatively influence MS2 inactivation by either 220 or 254 nm irradiation, and that a lower UV dose of 220 nm irradiation can be used to achieve the same level of inactivation in water containing AOM.

25217. 题目: Marine ammonification and carbonic anhydrase activity induce rapid calcium carbonate precipitation
文章编号: N18092608
期刊: Geochimica et Cosmochimica Acta
作者: S. Krause, V. Liebetrau, C.R. Löscher, F. Böhm, S. Gorb, A. Eisenhauer, T. Treude
更新时间: 2018-09-26
摘要: During Earth’s history, precipitation of calcium carbonate by heterotrophic microbes has substantially contributed to the genesis of copious amounts of carbonate sediment and its subsequent lithification. Previous work identified the microbial sulfur and nitrogen cycle as principal pathways involved in the formation of marine calcium carbonate deposits. While substantial knowledge exists for the importance of the sulfur cycle, specifically sulfate reduction, with regard to carbonate formation, information about carbonate genesis connected to the microbial nitrogen cycle is dissatisfactory. In addition to the established pathways for carbonate mineral formation, also the potential of microbial carbonic anhydrase, a carbonate-relevant, zinc-containing enzyme, is receiving currently increased attention. However, also in this field knowledge is scarce and fragmentary. Here we demonstrate microbial carbonate precipitation as a direct result of the interplay between the microbial nitrogen cycle and a microbially produced enzyme. Using Alcanivorax borkumensis as a model organism, our experiments depict precipitation of a peloidal carbonate matrix within days to weeks, induced by simultaneous ammonification and extracellular carbonic anhydrase activity. The precipitates show similar morphology, mineralogy, δ^44/40Ca, and δ ^88/86Sr to analogs of modern carbonate peloids. The obtained Sr/Ca partition coefficient D_Sr showed no clear deviation from inorganic carbonate phases, indicating that microbially mediated carbonate precipitation, indeed, follows the principles of physico-chemical precipitation. The observed relative enrichment of the precipitates in zinc might help to constrain zinc variations in natural carbonate archives. Our study demonstrates that ammonification, due to intense microbial organic matter degradation, and carbonic anhydrase may play a substantial role for calcium carbonate precipitation in paleo- and recent shallow marine environments.

25218. 题目: Visible-light-driven photocatalytic inactivation of bacteriophage f2 by Cu-TiO₂ nanofibers in the presence of humic acid
文章编号: N18092607
期刊: Journal of Environmental Sciences
作者: Rong Cheng, Mi Kang, Zhi-peng Shen, Lei Shi, Xiang Zheng
更新时间: 2018-09-26
摘要: Pathogenic viruses in drinking water are great threats to public health. Visible-light-driven photocatalysis is a promising technology for virus inactivation. However, the existing photocatalytic antiviral research studies have mostly been carried out in single-component systems, neglecting the effect of natural organic matter, which exists widely in actual water bodies. In this paper, electrospun Cu-TiO₂ nanofibers were prepared as photocatalysts, and their photocatalytic antiviral performance in the presence of humic acid (HA) was comprehensively studied for the first time. The properties of the reaction mixture were measured during the reaction. In addition, the safety, reliability and stability of photocatalytic disinfection in the mixed system were evaluated. The results showed that the virus removal efficiency decreased with the increase of the HA concentration. The type of reaction solution, such as PBS buffer solution or water, did not affect the removal efficiency noticeably. Under acidic conditions, the electrostatic forces between photocatalysts and viruses were strengthened, leading to higher virus removal efficiency. As the reaction time went on, the pH value in the solution increased first and then tended to be stable, the conductivity remained stable, and the dissolved oxygen increased first and then decreased. The safety test showed that the concentration of Cu ions released into the solution was lower than specified by the international standards. No photoreactivation was observed, and the addition of HA significantly reduced the reutilization efficiency of the photocatalysts.
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25219. 题目: Stable carbon isotope records of black carbon on Chinese Loess Plateau since last glacial maximum: An evaluation on their usefulness for paleorainfall and paleovegetation reconstruction
文章编号: N18092606
期刊: Palaeogeography, Palaeoclimatology, Palaeoecology
作者: Xu Wang, Linlin Cui, Shiling Yang, Jixuan Zhai, Zhongli Ding
更新时间: 2018-09-26
摘要: Stable carbon isotope composition of soil organic matter (δ¹³C_SOM) has been widely used to infer past environmental or vegetation (C₃/C₄) changes. However, as a carbonaceous product of incomplete burning of biomass, the carbon isotope signature of black carbon (BC) has received little study and a limited usage on this purpose. Moreover, the environmental or vegetation indication of BC carbon isotope composition (δ¹³C_BC) in sedimentary records remains ambiguous although the δ¹³C_BC is supposed to reflect carbon isotope composition of vegetation being burnt. This deserves site-specific studies. Here we analyzed δ¹³C_BC and δ¹³C_SOM on loess-paleosol samples from Lijiayuan and Yangling sections on Chinese Loess Plateau (CLP) spanning the last glacial maximum to decipher the environmental (or vegetation) meaning of δ¹³C_BC at each study site. Opposite changing patterns were observed on the δ¹³C_BC values for the two sections. The δ¹³C_BC at Yangling (in southern part of the CLP) varied from − 19.18‰ to − 21.93‰ (mean: − 20.62‰) with more positive values occurred during the middle Holocene than those during the LGM, demonstrating more C₄ plants occupied in the region during the warm-humid middle Holocene. This is consistent with the changing pattern widely-documented in δ¹³C_SOM records over the CLP during the same period. By contrast, the δ¹³C_BC at Lijiayuan (in northwestern part of the CLP) changed within the range of − 21.83‰ ~ − 24.64‰ (mean: − 23.34‰) and displayed more negative values during the early-middle Holocene with respect to the LGM period. The δ¹³C_BC at Lijiayuan were about 2.5‰ lower than those at Yangling, indicating a northward decrease of C₄ plants on the CLP. The anti-phased changes of δ¹³C_BC at Lijiayuan were considered to reflect variations in paleorainfall because the vegetation is dominated by C₃ plants at the study site and carbon isotope compositions of C₃ plants decrease as rainfall increases. Compared with δ¹³C_SOM record at the same profile, δ¹³C_BC seem biased against capturing C₄ signal during mid-Holocene possibly due to dominance of C₃ plants at the study site during fire seasons and a potentially extra source of BC from forest fires occurred on surrounding mountains. By contrast, δ¹³C_BC tend to exaggerate C₄ signal during the LGM attributed to a possible shift of fire season from spring to summer. These findings suggest that we probably underestimate the abundance of C₄ plants during mid-Holocene and overestimate C₄ biomass during the LGM using BC carbon isotope composition.

25220. 题目: Insight into the short- and long-term effects of quinoline on anammox granules: Inhibition and acclimatization
文章编号: N18092605
期刊: Science of The Total Environment
作者: Qian-Qian Chen, Lian-Zeng-Ji Xu, Zao-Zao Zhang, Fan-Qi Sun, Zhi-Jian Shi, Bao-Cheng Huang, Nian-Si Fan, Ren-Cun Jin
更新时间: 2018-09-26
摘要: The short- and long-term influence of quinoline on the properties of anaerobic ammonium oxidation (anammox) biogranules was evaluated. During batch tests, the bioactivity of anammox granules in the presence of different quinoline concentrations was monitored, and the IC₅₀ of quinoline was calculated to be 13.1 mg L⁻¹ using a non-competitive inhibition model. The response of anammox granules to pre-exposure to quinoline was dependent on metabolic status, and the presence of both quinoline and NO₂⁻-N had a rapid detrimental effect, resulting in a 64.5% decrease within 12 h. During continuous-flow experiments, the nitrogen removal rate (NRR) of the reactor decreased sharply within 3 days in the presence of 10 mg L⁻¹ quinoline and then was restored to 2.6 kg N m⁻³ d⁻¹. In the presence of quinoline-induced stress, the specific anammox activity and levels of extracellular polymeric substance and heme c were decreased, while settling velocity persistently increased. After cultivation and acclimation obtained by adding a medium level of quinoline to the influent, the anammox granule sludge was able to tolerate 10 mg L⁻¹ quinoline in 178 days.
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