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25801. 题目: A new pathway of monomethylmercury photodegradation mediated by singlet oxygen on the interface of sediment soil and water
文章编号: N19030710
期刊: Environmental Pollution
作者: Feng Sheng, Jingyi Ling, Ran Hong, Xin Jin, Chao Wang, Huan Zhong, Xueyuan Gu, Cheng Gu
更新时间: 2019-03-07
摘要: Photodegradation is an important pathway for monomethylmercury (MeHg) degradation in aquatic ecosystems. In this process, dissolved organic matter (DOM) plays an essential role. However, little information is available regarding the photo-transformation of MeHg in shallow aquatic environments, where a significant portion of MeHg is associated with soil suspensions. In this study, 14 soils sampled from different sites in China were used to simulate these conditions. Our results clearly demonstrated that soil organic matter (SOM) was the most important factor controlling the MeHg photodegradation in suspension. Degradation in this heterogeneous aqueous system was shown to be mediated by the ¹O₂ produced by organic matter on the surface of the soil particles rather than by DOM. This was confirmed by the strong correlation between the kinetics rate constant of MeHg degradation and steady state concentrations of ¹O₂ (R² = 0.81). Our results propose a new pathway of MeHg induced by sediment soils under sunlight irradiation. Identification of this pathway may improve the estimates of potential ecological risk of Hg in shallow field ecosystems.
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25802. 题目: Fate of particle-bound polycyclic aromatic hydrocarbons in the river-influenced continental margin of the northern Gulf of Mexico
文章编号: N19030709
期刊: Marine Pollution Bulletin
作者: P.L. Adhikari, K. Maiti, W. Bam
更新时间: 2019-03-07
摘要: This study utilizes suspended particles and seafloor sediments collected from the northern Gulf of Mexico (GOM) continental margin to study the fate, transport, residence times and accumulation rates of particle-bound polycyclic aromatic hydrocarbons (PAHs). Total particulate-PAHs and particulate organic carbon (POC) varied between 0.9 and 7.0 ng/L, and 4–131 μg/L, respectively. Particulate-PAHs were positively correlated with POC, while both particulate-PAHs and POC were negatively correlated with salinity (P-value < 0.05). These results show that the river-derived particle influx and associated POC are important vectors for transport and fate of particulate-PAHs in the river-dominated northern GOM continental ecosystems. The composition of underlying seafloor sediment-PAHs were not correlated to the water column particulate-PAHs, which is attributed to re-mineralization, sediment resuspension/redistribution and different timescales of comparison. The ²¹⁰Pb-derived residence time of particles and associated particulate-PAHs in water column varied between 2 and 39 days. Residence times of particulate-PAHs were significantly correlated with seafloor sediment-PAHs accumulation rates, shorter water column residence times leading to higher PAHs accumulation rates.
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25803. 题目: Lipid biomarker and stable isotopic profiles through Early-Middle Ordovician carbonates from Spitsbergen, Norway
文章编号: N19030708
期刊: Organic Geochemistry
作者: Carina Lee, Gordon D. Love, Melanie J. Hopkins, Björn Kröger, Franziska Franeck, Seth Finnegan
更新时间: 2019-03-07
摘要: One of the most dramatic episodes of sustained diversification of marine ecosystems in Earth history took place during the Early to Middle Ordovician Period. Changes in climate, oceanographic conditions, and trophic structure are hypothesised to have been major drivers of these biotic events, but relatively little is known about the composition and stability of marine microbial communities controlling biogeochemical cycles at the base of the food chain. This study examines well-preserved, carbonate-rich strata spanning the Tremadocian through Upper Dapingian stages from the Oslobreen Group in Spitsbergen, Norway. Abundant bacterial lipid markers (elevated hopane/sterane ratios, average = 4.8; maximum of 13.1), detection of Chlorobi markers in organic-rich strata, and bulk nitrogen isotopes (δ¹⁵N_total) averaging 0 to -1‰ for the open marine facies, suggest episodes of water column redox-stratification and that primary production was likely limited by fixed nitrogen availability in the photic zone. Near absence of the C₃₀ sterane marine algal biomarker, 24-n-propylcholestane (24-npc), in most samples supports and extends the previously observed hiatus of 24-npc in Early Paleozoic (Late Cambrian to Early Silurian) marine environments. Very high abundances of 3β-methylhopanes (average = 9.9%; maximum of 16.8%), extends this biomarker characteristic to Early Ordovician strata for the first time and may reflect enhanced and sustained marine methane cycling during this interval of fluctuating climatic and low sulfate marine conditions. Olenid trilobite fossils are prominent in strata deposited during an interval of marine transgression with biomarker evidence for episodic euxinia/anoxia extending into the photic zone of the water column.

25804. 题目: Biochar's role as an electron shuttle for mediating soil N₂O emissions
文章编号: N19030707
期刊: Soil Biology and Biochemistry
作者: Haijing Yuan, Zhijun Zhang, Mengya Li, Tim Clough, Nicole Wrage-Mönnig, Shuping Qin, Tida Ge, Hanpeng Liao, Shungui Zhou
更新时间: 2019-03-07
摘要: The functionality of biochar as an electron shuttle has been hypothesized to rationalize its suppressing effect on nitrous oxide (N₂O) emissions from soil denitrification. However, this hypothesis has not yet been experimentally confirmed in soil matrices. In this study, we weakened biochar's function as an electron shuttle using a hydrogen peroxide pretreatment. Biochar addition supressed soil N₂O emissions compare to a nil biochar control, but oxidized biochar increased soil N₂O emission rates and N₂O/(N₂O + N₂) emission ratio. The increasing extent of the soil N₂O emission rate significantly correlated positively with the abundance of the biochar's oxidative moieties (e.g., C=O groups). These results imply that addition of biochar with a strong electron shuttle function will decrease soil N₂O emissions whereas biochar aging will weaken or even reverse the suppressing effects on soil N₂O emissions.

25805. 题目: Dependence of temperature sensitivity of soil organic carbon decomposition on nutrient management options under conservation agriculture in a sub-tropical Inceptisol
文章编号: N19030706
期刊: Soil and Tillage Research
作者: C.M. Parihar, A.K. Singh, S.L. Jat, A. Ghosh, A. Dey, H.S. Nayak, M.D. Parihar, D.M. Mahala, R.K. Yadav, V. Rai, T. Satayanaryana, M.L. Jat
更新时间: 2019-03-07
摘要: Assessment of temperature sensitivity of soil organic carbon (SOC) mineralization from soils of long-term precision conservation agriculture (CA) plots is essential to forecast soil C dynamics. Under CA, varying quantity of inorganic nutrient application had differential impact on SOC. At the same time study of SOC mineralization at different simulated temperatures is important as global climate change affects C-cycle of an agro-ecosystem. To assess the impact of tillage and nutrient management on SOC build-up, a long-term study (five year old) with 3-tillage practices [ZT-zero tillage; PB-permanent beds, & CT-conventional tillage] in main plot and 4-nutrient management strategies [unfertilized, farmer fertilizer practice-FFP, recommended fertilizers-Ad-hoc and a site specific nutrient management-SSNM] in sub-plot in a maize-wheat-mungbean system was chosen. To measure the build-up and thermal sensitivity of SOC, soil samples from 3- depths (0–7.5, 7.5–15 and 15–30 cm) were collected. The kinetics of C-mineralisation was studied through laboratory incubation at 3-temperatures (27, 32 and 37 °C) for 90 days. The PB/ZT and SSNM had significantly higher SOC compared with CT and unfertilized plots, respectively. Although the cumulative C mineralization after 90-days of incubation followed the trend of SOC content among the treatments, while decay rates of SOC mineralization showed somewhat different trend. In all the tillage treatments the percentage of SOC mineralised ranged between 3.3–5.8% at 27 °C, 5.2–8.1% at 32 °C and 7.3–10.9% at 37 °C. At higher temperature, higher SOC decay rates were observed under CT and unfertilized plots compared with PB/ZT and SSNM plots, respectively. The SOC from lower soil depth in CT and unfertilized plots was more temperature sensitive (Q₁₀ = 4.03 and 4.89, respectively) compared to those under CA-based PB/ZT (Q₁₀ = 2.63–2.82) and SSNM (Q₁₀ = 2.15) based balanced nutrition, respectively. The SOC in lower soil depth (7.5–15 and 15–30 cm) is 1.3 and 2.1 times more temperature sensitive respectively than surface soil depth of 0–7.5 cm soil depth. Higher proportion of less labile SOC under CT and unfertilized plots might be the reason for higher temperature sensitivity. In the inevitable and impending global climate change scenario, we might lose a sizeable amount of sequestered C, which is otherwise stable at present ambient temperature.

25806. 题目: Noncovalent interactions between fluoroquinolone antibiotics with dissolved organic matter: A ¹H NMR binding site study and multi-spectroscopic methods
文章编号: N19030705
期刊: Environmental Pollution
作者: Xiating Zhao, Zhongzheng Hu, Xing Yang, Xuewei Cai, Zhaowei Wang, Xiaoyun Xie
更新时间: 2019-03-07
摘要: Fluoroquinolone antibiotics (FQs) are considered to be emerging environmental contaminants that have been detected extensively in aquatic environment. It is of quite importance to explore FQs interacting with dissolved organic matter (DOM). The interactions of FQs with DOM were examined by nuclear magnetic resonance (NMR) spectroscopy, fluorescence quenching, UV–vis, Fourier transform infrared (FT-IR) spectroscopic techniques. The bindings of FQs to DOM had one single binding site and their quenching mechanisms were static, which were evaluated by the Stern-Volmer and Site-binding equations. Addition of DOM could result in micro-environmental changes of fluorophores groups in FQs. The location adjacent oxygen right of Ofloxacin (OFL) and the aromatic ring (the adjacency replaced by two nitrogen-containing groups) of Ciprofloxacin (CIP), Enrofloxacin (ENR), Norfloxacin (NOR) might be highly affected by DOM molecule. The negative enthalpy change (ΔH⁰), negative entropy change (ΔS⁰) and the positive Gibbs' energy change (ΔG⁰) figured out that the binding processes were exothermic but not thermodynamic favorable, the formation of HA-FQs complexes would be powered chiefly by the ΔS⁰. H-bonding, electrostatic effect, van der Waals force were the acting force in the binding reactions and the π-π stacking effect was the major binding force under alkaline conditions. Moreover, the protonated, deprotonated, or partially protonated state of FQs were found to have different binding capacity to DOM, and the binding reactions for FQs-HA system were suppressed as the ionic strength increased. Meanwhile, alterations of FQs conformation in the presence of DOM were evaluated by FT-IR and UV–vis spectra.
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25807. 题目: Potential of dissolved organic matter (DOM) to extract As, Cd, Co, Cr, Cu, Ni, Pb and Zn from polluted soils: A review
文章编号: N19030704
期刊: Geoderma
作者: Ole K. Borggaard, Peter E. Holm, Bjarne W. Strobel
更新时间: 2019-03-07
摘要: Pollution of soils with As, Cd, Co, Cr, Cu, Ni, Pb and Zn, collectively termed heavy metals (HMs), can threaten human health and ecosystem functioning. Therefore, polluted soils must be remediated. Soil washing of strongly polluted soils and phytoextraction on moderately polluted sites seem currently the most attractive remediation methods. Both methods depend on HM solubility (extractability), which can be increased by addition of ligands such as EDTA, NTA and other aminopolycarboxylic acids. As an alternative to these synthetic and environmentally questionable chemicals, the possibility of using naturally occurring dissolved organic matter (DOM) to extract the HMs from anthropogenic polluted soils is evaluated in this review based on mainly recently published laboratory studies. DOM isolated or extracted from soils consists of fulvic acid (FA) with up to 10% low-molecular-weight-organic-acids (LMWOAs), e.g. citric, oxalic and salicylic acids. In addition to soil DOM, results with other soluble humic substances and organic waste materials have been included, e.g. food wastes that after composting give useful LMWOAs.Although generally less efficient than EDTA and NTA, the review clearly shows potential of DOM as HM extractant. Through its carboxylate and/or phenolate functional groups, DOM can form soluble complexes with Cd²⁺, Co²⁺, Cu²⁺, Ni²⁺, Pb²⁺ and Zn²⁺ (and other di- and trivalent cations). Extraction of anionic As(III), As(V) and Cr(VI) sorbed by soil solids, mainly amorphous Al and Fe oxides, is accomplished by DOM dissolution of the sorbents (oxides). In addition to the soil HM extraction potential, use of DOM will probably extract organic pollutants, stimulate microbial activity and improve soil structure. On the other hand, the efficiency of DOM to extract HMs (and other pollutants) seems to depend of numerous variables/factors including the specific HM, DOM and polluted soil as well as environmental (external) conditions such as pH, solution:soil ratio, extraction time and metal loading of the extractant. Furthermore, several different studies have shown conflicting (inconclusive) results, e.g. of pH and ageing effects on HM extractability. Therefore, much is still to be learnt about different DOM-HM-soil systems and their dependency of external factors. To create operational and safe guidelines for using DOM as HM extractant in relation to remediation of polluted field soils by phytoextraction or soil washing, considerably more precise knowledge is needed on influence of composition of different DOM samples and of characteristics of the polluted soils for extraction of the different HMs under various, clearly specified environmental conditions. If future investigations confirm the suitability of DOM in soil remediation, the next challenges will be upscaling to field conditions as well as to ensure availability of enough good quality DOM and to complete state-of-art economic analysis of using DOM in operational phytorextraction and soil washing.

25808. 题目: Energetic valorization of MSW compost valorization by selecting the maturity conditions
文章编号: N19030703
期刊: Journal of Environmental Management
作者: V.M. Doña-Grimaldi, A. Palma, M. Ruiz-Montoya, E. Morales, M.J. Díaz
更新时间: 2019-03-07
摘要: MSW compost valorization under combustion, at two different composting process conditions, have been studied by thermogravimetric analysis (TGA). The composting operating parameters such as aeration and moisture affect the biodegradability of compost and results of the combustion (different gross heating values for each reactors). The obtained TGA showed that maximum weight loss for 10–12% (245–247 °C), 32–34% (407–411 °C) and 44–46% (760–769 °C) in correspondence to hemicellulose, cellulose and lignin-humic-fulvic acids decomposition for each reactor are observed. Obtained valued in kinetic study (Flynn-Wall-Ozawa method) results in suitable coefficients of determination. In that form, to establish the assumption that combustion of compost under a first-order reaction may be appropriate. Moreover, in both reactors, the conversion rate increased and the activation energy decreased with composting time is found. The maximum gross heating value versus minimum activation energy (for α = 0.25 and α = 0.5) corresponds to final composts and under aeration of 0.050 and 0.175 L_air kg⁻¹ d⁻¹ and moisture of 40% and 55% for R1 and R2 reactors respectively. For MSW, under proper conditions, composting could be used as a suitable biodrying process, stabilizing and concentrating the heating value.

25809. 题目: Understanding the thermal degradation patterns of hopane biomarker compounds present in crude oil
文章编号: N19030702
期刊: Science of The Total Environment
作者: Yuling Han, Gerald F. John, T. Prabhakar Clement
更新时间: 2019-03-07
摘要: In-situ burning (ISB) is a common oil spill response technique used for managing marine oil spills. The burnt residues generated from ISB can have several toxic compounds and therefore their impacts on aquatic ecosystem are of major environmental concern. When quantifying the fate of the toxic compounds in ISB residues, C₃₀-αβ hopane is routinely used as a conservative biomarker since it has shown to be resistant to most natural weathering processes. However, a recent laboratory study has shown that C₃₀-αβ and other hopane compounds have the potential to degrade when crude oil was physically burnt under controlled conditions. When crude oil is burnt, the temperature of the oil can raise up to 350–500 °C; however, so far, no one has studied the fate of hopanes when crude oil is simply heated to very high temperatures. In this study, we hypothesize that heating crude oil to very high temperatures would result in the degradation of hopane compounds. Results of our study show that C₃₀-αβ hopane in crude oil will start to degrade at around 160 °C and the degradation pattern follows first order kinetics. Other types of hopanes and their diagnostic ratios can also change when the oil is exposed to severe heating conditions. We conclude that removal of hopane biomarkers via thermal degradation is a possible depletion pathway during ISB. Therefore, caution should be exercised when using hopanes as conservative biomarker compounds for characterizing ISB residues.
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25810. 题目: Biochar increases pesticide-detoxifying carboxylesterases along earthworm burrows
文章编号: N19030701
期刊: Science of The Total Environment
作者: Juan C. Sanchez-Hernandez, Ximena Andrade Cares, Mariana Adrián Pérez, Jesús Notario del Pino
更新时间: 2019-03-07
摘要: Herein, we examined whether synergistic effects of earthworms (Lumbricus terrestris) and pine needle-derived biochar result in biochar-coated burrows with enhanced carboxylesterase (CE) activity (a pesticide-detoxifying enzyme). Biochar was placed at the top of soil columns at two doses (2.5 and 5% w/w dry mass), with an additional biochar-free treatment as control. Carboxylesterase and dehydrogenase activities were measured in the burrow walls sampled at three depths (0–4, 8–12, and 18–22 cm). Biochar was recovered from these samples to confirm its vertical transport and enzymatic activation. We tested whether biochar protected CE activity against desiccation stress of burrow wall samples. Likewise, the role of earthworm mucus in stabilizing CE onto biochar surface was also investigated by measuring the enzyme activity in fresh biochar particles previously incubated in the presence of earthworm mucus and purified esterase. Finally, we checked for the sensitivity of biochar-bound CE activity against selected organophosphorus pesticides. The main results were: i) co-application of earthworms and biochar caused a significant increase of CE activity in the first 12 cm of the soil column, ii) recovered biochar particles displayed CE activity which was significantly higher in the particles collected from the bottom of columns, iii) soil desiccation decreased the enzymatic activity, although such effect depended on biochar treatment and column depth (22–77% inhibition). Nevertheless, CE activity still was higher in the samples from the 5%-biochar treatment than activity in control and 2.5%-biochar treatments, iv) earthworm mucus favored the retention of CE onto the biochar surface, and v) the activity of biochar-bound CE was sensitive to inhibition by chlorpyrifos-oxon. These results suggest that the joint application of L. terrestris and biochar may be a suitable vermiremediation strategy to inactivate OP pesticides.
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25811. 题目: The transformation of macrophyte‐derived organic matter to methane relates to plant water and nutrient contents
文章编号: N19030609
期刊: Limnology and Oceanography
作者: Charlotte Grasset, Gwenaël Abril, Raquel Mendonça, Fabio Roland, Sebastian Sobek
更新时间: 2019-03-06
摘要: Macrophyte detritus is one of the main sources of organic carbon (OC) in inland waters, and it is potentially available for methane (CH₄) production in anoxic bottom waters and sediments. However, the transformation of macrophyte‐derived OC into CH₄ has not been studied systematically, thus its extent and relationship with macrophyte characteristics remains uncertain. We performed decomposition experiments of macrophyte detritus from 10 different species at anoxic conditions, in presence and absence of a freshwater sediment, in order to relate the extent and rate of CH₄ production to the detritus water content, C/N and C/P ratios. A significant fraction of the macrophyte OC was transformed to CH₄ (mean = 7.9%; range = 0–15.0%) during the 59‐d incubation, and the mean total C loss to CO₂ and CH₄ was 17.3% (range = 1.3–32.7%). The transformation efficiency of macrophyte OC to CH₄ was significantly and positively related to the macrophyte water content, and negatively to its C/N and C/P ratios. The presence of sediment increased the transformation efficiency to CH₄ from an average of 4.0% (without sediment) to 11.8%, possibly due to physicochemical conditions favorable for CH₄ production (low redox potential, buffered pH) or because sediment particles facilitate biofilm formation. The relationship between macrophyte characteristics and CH₄ production can be used by future studies to model CH₄ emission in systems colonized by macrophytes. Furthermore, this study highlights that the extent to which macrophyte detritus is mixed with sediment also affects CH₄ production.

25812. 题目: Molecular hysteresis: Hydrologically‐driven changes in riverine dissolved organic matter chemistry during a storm event
文章编号: N19030608
期刊: Journal of Geophysical Research: Biogeosciences
作者: Sasha Wagner, Jennifer Hoyle Fair, Serena Matt, Jacob Hosen, Peter Raymond, James Saiers, Jamie Shanley, Thorsten Dittmar, Aron Stubbins
更新时间: 2019-03-06
摘要: Hydrological events, driven by rainfall, control the amount and composition of dissolved organic matter (DOM) mobilized through river networks. In forested watersheds, the concentration, composition, and reactivity of DOM exported changes as base flow transitions to storm flow, with major implications to downstream biogeochemistry. Hysteresis describes an observed difference between in‐stream solute concentration/signal and discharge. By studying the relationship between DOM and stream discharge, we refine our understanding of the environmental and hydrological factors that influence the quantity and quality of stream DOM. The main objective of this study was to track hysteretic changes in riverine DOM molecular composition during storm events. Samples were collected from nested sites within the Passumpsic River catchment (Vermont, USA), a tributary of the Connecticut River. High resolution monitoring of fluorescent DOM (via in‐situ sensors) and automated collection of discrete samples captured short‐term, hydrologically‐driven variations in DOM concentration and composition. Ultrahigh resolution mass spectrometry revealed an enrichment in aliphatic compounds at storm onset, while aromatic and polyphenolic compounds were more enriched at peak discharge. Molecular hysteresis patterns were similar across stream orders, indicating that fresh, terrigenous DOM is quickly shunted downstream, through the river network, during pulses of high discharge.

25813. 题目: Diel changes in aquatic biogeochemistry of a pristine stream receiving untreated urban sewage at Brazilian rainforest
文章编号: N19030607
期刊: Environmental Science and Pollution Research
作者: Debora Alves Santos, Francisco Carlos Fernandes De Paula
更新时间: 2019-03-06
摘要: Freshwater bodies experience diel variations in aquatic chemistry, driven by natural processes. However, changes in land use, like urbanization, can modify the natural dynamics of such systems. This article describes changes in biogeochemistry of a pristine stream after receiving untreated sewage of an urban nucleus. Water samples were collected and field parameters measured, during low flow period. Temperature, pH, dissolved oxygen, electric conductivity, turbidity, total suspended solids, silicate, N-NO₃, N-NO₂, N-NH₄, dissolved and particulate organic nitrogen, PO₄, and dissolved and particulate organic phosphorus were measured hourly during a diel cycle. Upstream hydrochemistry resembles pristine watersheds in tropical rainforest, and results are restricted to a narrow range of values during the entire sampling period. Conversely, values downstream varied widely and, for some analytes, presented differences between day and night. Dissolved oxygen and electric conductivity showed the effect of the urban pulse, varying according to the routine of the population. Other field parameters did no presents a pattern that could distinguish up- and downstream stations. All the nutrients, but silicate, increased in concentration downstream. Particulate organic phosphorus, N-NO₂, and N-NH₄ were the nutrients that highlight the magnitude of the changes driven by urban effluents. These three nutrient species, and dissolved organic phosphorus, revealed a remarkably pattern that reflects the routine of the urban population, with low concentrations at night and a progressive increase starting at the early morning.

25814. 题目: A hydrothermal-carbonization process for simultaneously production of sugars, graphene quantum dots, and porous carbon from sugarcane bagasse
文章编号: N19030606
期刊: Bioresource Technology
作者: Xinyu Chai, Hui He, Hanhan Fan, Xiheng Kang, Xueping Song
更新时间: 2019-03-06
摘要: A green and facile approach was proposed to simultaneously produce fermentative sugar (FS), graphene quantum dots (GQDs), and hierarchical porous carbon (HPC) from sugarcane bagasse through the hydrothermal-carbonization process. In this work, the maximum yields of FS were 35.77%, 30.54%, 1.23%, 28.52%, and 41.85% for xylose, mannose, glucose, galactose, and arabinose, respectively. The GQDs, with bright blue fluorescence, had an average diameter at 2.26 nm, and exhibited a well-defined spherical shape and graphene structure. The formation mechanism of GQDs was further investigated, and the GQDs mainly derived from the dissolved lignin and polysaccharides. Moreover, the HPC presented a much higher surface area and controllable oxygen content than non-hydrothermal pretreatment porous carbon, whose unique pore structure was mainly resulted from the dissolution of FS. The green and facile approach provides a novel pathway to produce high value-added materials from sugarcane bagasse, developing a foundation for the preparation of better biomass materials.
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25815. 题目: Modelling carbofuran biotransformation by Novosphingobium sp. KN65.2 in the presence of coincidental carbon and indigenous microbes
文章编号: N19030605
期刊: Environmental Science: Water Research & Technology
作者: Li Liu, Damian E. Helbling, Hans-Peter Kohler, Barth F. Smets
更新时间: 2019-03-06
摘要: The influence that coincidental carbon substrates (i.e., assimilable organic carbon, AOC) and indigenous microbial communities have on pesticide biotransformation by degrader strains in aquatic environments is poorly understood. We conducted batch experiments to investigate carbofuran biotransformation by Novosphingobium sp. KN65.2 using four environmentally derived water samples with varying amounts and types of AOC and indigenous microbial communities. We designed experimental scenarios to explore the influence of AOC and indigenous microbial communities on the growth of strain KN65.2 and the biotransformation of carbofuran. Relevant kinetic parameters were estimated from simpler experiments, and used to predict the growth of strain KN65.2 and the biotransformation of carbofuran in more complex experiments with an additive biokinetic model. We found that our additive biokinetic model adequately predicts the growth of strain KN65.2 and the rate of carbofuran biotransformation in natural waters that support the growth of strain KN65.2 in the absence of a carbofuran supplement. However, our model over-predicts the growth of strain KN65.2 and the rate of carbofuran biotransformation in low-AOC environments. Overall, our results define the scope within which additive biokinetic models can be used to predict pesticide biotransformation in the presence of coincidental carbon substrates and indigenous microbial communities.

25816. 题目: Simultaneous nitrification, denitrification and phosphorus recovery (SNDPr) - An opportunity to facilitate full-scale recovery of phosphorus from municipal wastewater
文章编号: N19030604
期刊: Journal of Environmental Management
作者: Sara Salehi, Ka Yu Cheng, Anna Heitz, Maneesha P. Ginige
更新时间: 2019-03-06
摘要: Sewage treatment plants are a potential point source for recycling of phosphorus (P). Several technologies have been proposed to biologically recover P from wastewater. The majority of these technologies are side-stream processes and rely on an external source of soluble organic carbon to facilitate P recovery. To date, no studies have demonstrated the potential to facilitate main-stream recovery of P, using carbon that is naturally present in wastewater. Simultaneous nitrification, denitrification and phosphorus removal (SNDPR) is an elegant process that can uptake influent carbon and effectively remove both nitrogen (N) and P from wastewater. SNDPR studies to date, however, have failed to facilitate an end-of-anaerobic-phase P rich liquor, that enables economies of scale to recover influent P. Therefore, this study examined the feasibility of achieving a P rich liquor (e.g. > 70 mg-P/L) in a granular SNDPR process. A synthetic influent that replicated the nutrient and carbon concentrations of municipal wastewater was used to investigate whether carbon in the influent wastewater could enable both nutrient removal and P recovery from wastewater. Our granular SNDPR process was able to facilitate an end-of-anaerobic-phase liquor with P enriched to approximately 100 mg-P/L. A dissolved oxygen (DO) concentration of 0.5 mg/L in a sequencing batch reactor (SBR) was found to be essential to achieve complete nutrient removal and a high P concentration at the end of the anaerobic phase. At this steady state of reactor operation, the abundance of polyphosphate accumulating organisms (PAOs) was 2.6 times the abundance of glycogen accumulating organisms (GAOs). The study also demonstrated the importance of denitrifying polyphosphate accumulating organisms (DPAOs) and glycogen accumulating organisms (DGAOs) to achieve complete removal of N from the effluent. Compared to nitrifying bacteria, the polyphosphate accumulating organisms (PAOs) had a higher affinity towards DO. This study, for the first time, showed that the mainstream recovery of P is feasible using a SNDPR process.

25817. 题目: Amelioration in nutrient mineralization and microbial activities of sandy loam soil by short term field aged biochar
文章编号: N19030603
期刊: Applied Soil Ecology
作者: Vineet Yadav, Shilpi Jain, Pooja Mishra, Puja Khare, Ashutosh K. Shukla, Tanmay Karak, Anil K. Singh
更新时间: 2019-03-06
摘要: The aging of biochar is an important parameter for its sustainable application. However, data on the impact of field-aging biochar on soil biological properties is limited. In this study, the impact of three months aged biochar soil mixture and fresh biochar soil mixture on the physico-chemical characteristics (morphology, functional groups, cation exchange and water holding capacities) and biological activity (microbial and soil enzymes) was compared. Cymbopogon winterianus-derived biochar was used for the experiment at three different application rates. The physico-chemical properties of soil collected at different time points suggested that weathering of biochar soil mixture significantly increases the labile organic carbon and cation exchange capacity. However, a decrease in pH and water holding capacity was also observed. In the aged biochar-soil mixture, the rate of mineralization was higher as compared to the fresh biochar-soil mixture. It provided better sites for adsorption of NH₄-N and NO₃-N. Aged soil biochar mixture had higher microbial and enzymatic activities (dehydrogenase, acidic and alkaline phosphatase and urease) as compared to fresh biochar soil mixture except for β-glucosidase. Our results suggest that short-term field weathering of biochar would be able to improve the soil biological properties significantly.

25818. 题目: Land management modifies the temperature sensitivity of soil organic carbon, nitrogen and phosphorus dynamics in a Ferralsol
文章编号: N19030602
期刊: Applied Soil Ecology
作者: Andry Andriamananjara, Tiphaine Chevallier, Dominique Masse, Herintsitohaina Razakamanarivo, Tantely Razafimbelo
更新时间: 2019-03-06
摘要: Land management and global warming affect the dynamics of soil organic matter (SOM) and nutrients such as nitrogen (N) and phosphorus (P). The effects depend on the type of SOM and on the temperature sensitivity of the SOM mineralization. There is insufficient data on tropical soils, which generally have low nutrient availability, to be able to predict the changes in SOM dynamics and, particularly, N and P availability with global warming. We studied at field scale, the influence of two land management systems, agroforestry (AGF) and traditional slash and burn agriculture (SB) on total carbon (C), available P and total N stocks in the 0–30 cm horizon of a Ferralsol in Madagascar. The soil under AGF stored more C and available P than the soil under SB. There was no clear difference for total N. A soil incubation laboratory experiment tested the effect on SOM mineralization of three factors: (i) land management (AGF or SB), (ii) increasing the temperature from 25 °C to 35 °C, and (iii) adding farmyard manure (FYM). The mineralization was assessed by measurements of microbial soil respiration (CO₂), available P (resin P) and total mineral N over a 59 day soil incubation experiment at 25 °C and 35 °C with or without FYM. During incubation, the soil respiration was higher for AGF than for SB but it was slightly less temperature sensitive for AGF (Q₁₀ = 1.2) than for SB (Q₁₀ = 1.4). The incubation temperature did not have a clear effect on the available P for either AGF or SB, suggesting that temperature did not affect P-fixation processes in the Ferralsol studied which had a high P sorption capacity. The temperature sensitivity of N mineralization was quite high in both systems (Q₁₀ = 3.4 after 42 days of incubation). The nutrient cycling processes (immobilization, mineralization) were faster at the higher temperature. Adding FYM increased slightly SOM mineralization and available P and mineral N, although exchange reactions in the Ferralsol limited P availability. Adding FYM modified the temperature sensitivity of SOM mineralization. It increased the temperature sensitivity of soil respiration, especially for AGF, but seemed to decrease the temperature sensitivity of N mineralization. Land use and management of Ferralsols affected the temperature sensitivity of SOM and nutrient dynamics and, in AGF soils, SOM seemed to be less temperature sensitive and have higher levels of nutrients.

25819. 题目: Linkage between soil nutrient and microbial characteristic in an opencast mine, China
文章编号: N19030601
期刊: Science of The Total Environment
作者: Anning Guo, Zhongqiu Zhao, Pengfei Zhang, Qiao Yang, Yufeng Li, Guangyao Wang
更新时间: 2019-03-06
摘要: Interaction between soil nutrients and microorganisms makes great contributions to soil quality in mining spoils of fragile ecological environment. While this was not very clear in opencast mine area located in western China. Based on an emerging tool of high-throughput sequencing and a comprehensive analysis method, canonical correlation analysis (CCA), the relationship between microorganisms dominant species and soil nutrients in mined areas located in Loess Plateau of China was studied. The results showed that soil and microbes both developed a lot after reclamation. Mean concentration of soil organic matter (SOM) and total phosphorus (TP) were higher than background value of chestnut soil, while total nitrogen (TN) and total potassium (TK) were lower than that. Soil nutrients and microorganisms in research areas were strongly correlated with each other. SOM, TN, TP, available phosphorus (AP) of soil system and Actinobacteria, Acidobacteria, Bacteroidetes of dominant bacterial species were closely related. Relevant efficient measures should be taken to store soil nutrients thus to activate bacterial performance for sustainable development.
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25820. 题目: Ten-year application of cattle manure contributes to the build-up of soil organic matter in eroded Mollisols
文章编号: N19030505
期刊: Journal of Soils and Sediments
作者: Shujie Miao, Yunfa Qiao, Yunfeng Yin, Jian Jin, Burger Martin, Xiaobing Liu, Caixian Tang
更新时间: 2019-03-05
摘要: Purpose: Amendment of animal manures into eroded soils is an important approach to improving nutrient status and increasing the concentration of soil organic carbon (SOC). However, the contribution of the manure carbon to SOC and its variation along soil profile has not been quantified. Materials and methods: We simulated soil erosion in a mollisol by removing the top soils of 0-, 5-, 10-, 20-, and 30-cm depth and compared SOC in soil profiles 10 years after either chemical fertilization alone or combined with cattle manure application. Results and discussion: Increasing erosion depth decreased SOC concentration and weakened soil aggregation. Compared to the chemical fertilization only, the addition of cattle manure significantly increased SOC accumulation and soil aggregation, which mainly occurred in 0–40-cm depths. The greatest effect of manure application was observed in the 10-cm erosion treatment. The application of cattle manure increased the ¹³C abundance in aggregates and bulk soil in the top 40 cm of soil profile. Using the natural ¹³C abundance method, we quantified the contribution of the cattle manure to SOC at 0–40-cm depths ranging from 1.1 to 8.4% across erosion treatments. Conclusions: The greatest contribution of the manure-C to SOC occurred in surface layer with 10 cm of soil removal. The application of animal manures was recommended for restoring severely eroded soils.