论文检索

总访问量：4705374次

总访客量：218211人

所有论文

26621. 题目: Nutrient regeneration mediated by extracellular enzymes in water column and interstitial water through a microcosm experiment
文章编号: N19032705
期刊: Science of The Total Environment
作者: Chunlei Song, Xiuyun Cao, Yiyong Zhou, Maurizio Azzaro, Luis Salvador Monticelli, Giovanna Maimone, Filippo Azzaro, Rosabruna La Ferla, Gabriella Caruso
更新时间: 2019-03-27
摘要: In coastal lakes the role of microorganisms in driving nutrients regeneration at different water depths and in sediments is not yet fully understood. The dynamics of microbial (algal and bacterial) abundance and bacterial activities involved in organic matter transformation were measured, together with nutrient concentrations, through a microcosm experiment set up using the oligotrophic Faro lake as a study model over a total period of 15 days and with a four-day frequency. Water column at different depths (surface, middle and bottom) and interstitial water obtained by sediment centrifugation were used in appropriate ratios (mixed 1:1 with surface waters) to fill 21-Litre plastic aquaria in order to simulate processes occurring in natural conditions. At early experimental period, the sharp decrease of dissolved organic nutrients and the abundant production of leucine aminopeptidase (LAP) and alkaline phosphatase (AP) in correspondence with high phytoplankton abundance in bottom and interstitial water reflected the relevance of organic nutrients for inorganic nutrients regeneration and phytoplankton growth. Size fractionation of LAP and AP as well as the positive relationship between microbial compartments suggested that bacteria and phytoplankton worked in close reciprocal synergy, and coupling of nitrogen and phosphorus regeneration, especially in bottom and interstitial waters, was observed. At later experimental period, the change in bacterial community, especially the increase of filamentous shaped cells, together with a simultaneous increase of protozoan abundance indicated that nutrient replenishment made the microbial loop structure more competitive. In oligotrophic conditions, such as those in Faro lake, organic nutrient enrichment of bottom and interstitial waters was associated with changes in the bacterial community, with consequent stimulation of extracellular enzymes to support phytoplankton growth. Nutrient availability from microbial regeneration resulted in an increased complexity of the microbial loop structure, with bacteria and phytoplankton adopting specific strategies to respond to the changing environment.
图文摘要:

26622. 题目: Agro-industrial residues as a unique support in a sand filter to enhance the bioactivity to remove microcystin-Leucine aRginine and organics
文章编号: N19032704
期刊: Science of The Total Environment
作者: Pratik Kumar, Heidi Dayana Pascagaza Rubio, Krishnamoorthy Hegde, Satinder Kaur Brar, Maximiliano Cledon, Azadeh Kermanshahi-pour, Sébastien Sauvé, Audrey Roy-Lachapelle, Rosa Galvez-Cloutier
更新时间: 2019-03-27
摘要: In the past, the versatility of a biosand filter has been successfully checked to counter suspended solids, metals, dissolved organic carbon (DOC), coliforms and other water quality parameters (WQPs) from the drinking water sources. In this study, cyanotoxin in the form of microcystin-LR (MC-LR) along with above-mentioned WQPs including nitrate, nitrite, and ammonia are analyzed for their removal using agro-residue based biosand filters (ARSFs) for 49 days (7 cycles). Three different agro-residue materials (ARMs) viz. deinking sludge (DSF), hemp fiber (HFF) and paper-pulp dry sludge (PPF) were used as the support material (top 5 cm) along with sand (49 cm) as the primary filter media to enhance the overall bioactivity. This enhancement in bioactivity is hypothesized to remove more MC-LR, DOC, coliform along with efficient nitrification/denitrification. Native bacterial community isolated from the filtration unit of a drinking water treatment plant (Chryseobacterium sp. and Pseudomonas fragi = X) along with the MC-LR-degrader: Arthrobacter ramosus (which was screened as the best biofilm-former among two other MC-LR-degraders tested) were used to inoculate the filters (all three ARSFs). Overall, DSF performed the best among all the ARSFs when compared to the sand filter (SFI) inoculated with the same bacterial strains (A + X). An increase in the bioactivity for ARSFs, particularly DSF was evident from the DOC removal (44 ± 11%, 15% more than SFI), coliform removal (92.7 ± 12.8%, 24% more than SFI), MC-LR removal (87 ± 14%, 13% more than SFI) and an effective nitrification/denitrification, reducing ammonia, nitrate and nitrite level to below guideline values. Toxic assessment using bioindicator (Rhizobium meliloti) revealed safe filter water only in case of DSF.
图文摘要:

26623. 题目: Orbitrap molecular fingerprint of dissolved organic matter in natural waters and its relationship with NDMA formation potential
文章编号: N19032703
期刊: Science of The Total Environment
作者: Maria José Farré, Adrián Jaén-Gil, Jeffrey Hawkes, Mira Petrovic, Núria Catalán
更新时间: 2019-03-27
摘要: N-nitrosodimethylamine (NDMA) is a disinfection byproduct that has been classified as probable human carcinogen by the US Environmental Protection Agency. According to the published literature, natural dissolved organic matter (DOM) can be a source of NDMA precursors in drinking water. New advances in chemical characterization of DOM with high resolution mass spectrometry (HRMS) are allowing researchers to understand these ultra-complex mixtures.The objective of this study is to investigate analytical methodologies based on HRMS to explore NDMA formation from natural waters. To this aim, different waters from drinking water reservoirs in Spain containing NDMA precursors (quantified by means of NDMA formation potential) in concentrations between 17 and 60 ng/L have been studied. The workflow includes DOM solid-phase extraction and Orbitrap analysis with and without chromatographic separation.Here, we show that the molecular composition of DOM across the studied drinking water reservoirs is correlated with the NDMA formation potential. In particular, we found that NDMA formation potential is associated with compounds with high hydrogen saturation (H/C ≥ 1.5), corresponding also to reservoirs with higher background nutrient concentrations and wastewater indicators. Further chromatographic fractionation did not allow better definition of these possible precursors as they were present in different fractions of the chromatogram, suggesting that they were isomerically complex.
图文摘要:

26624. 题目: Controls on soil organic carbon stability and temperature sensitivity with increased aboveground litter input in deciduous forests of different forest ages
文章编号: N19032702
期刊: Soil Biology and Biochemistry
作者: Yini Ma, Melissa K. McCormick, Katalin Szlavecz, Timothy R. Filley
更新时间: 2019-03-27
摘要: A previous 5-year long field litter manipulation study at the Smithsonian Environmental Research Center (SERC) in coastal Maryland demonstrated that forest age controls the chemical trajectory of litter decay and the extent and source of litter incorporation into soil physical fractions among young (60–74 yrs) and old (113–132 yrs) successional stands. To investigate if these ecosystem-level differences influence soil organic carbon (SOC) stability and temperature sensitivity, and to infer differences in stabilization mechanisms, a six-month laboratory incubation (15 °C and 25 °C) of soils from the experimental plots was conducted. The results showed that: 1) C mineralization of wood amended soils was lower than control soils in all forests with young and old forests exhibiting distinct, early vs. late, CO₂ efflux profiles over the time course of the incubation; 2) Soils from leaf-amended old forests exhibited a proportional increase in their active SOC pool but with shorter mean residence times (MRT) and a decrease in slow pools with longer MRTs, while SOC of young forests proportionally shifted to more slow cycling SOC pools with MRTs that were unchanged from controls. Structural equation modeling combining previous field and soil property data with laboratory incubation results indicated that temperature sensitivity of the active SOC pool was related to the microbial community and lignin content, while temperature sensitivity of the slow pool was related to chemical protection from silts and clays, environmental factors like pH, and soil C/N ratio. Our results underscore how successional forests of differing age can exhibit dramatically different controls on SOC-litter dynamics, through the protection and accessibility of C, that must be taken into account when predicting forest ecosystem response to future climate change.
图文摘要:

26625. 题目: Pre-coagulation coupled with sponge-membrane filtration for organic matter removal and membrane fouling control during drinking water treatment
文章编号: N19032701
期刊: Water Research
作者: Lijuan Deng, Huu-Hao Ngo, Wenshan Guo, Hongwei Zhang
更新时间: 2019-03-27
摘要: A new hybrid system was developed in this study for the treatment of drinking water consisting of pre-coagulation using polyaluminium chloride (PACl) and membrane filtration (MF) with sponge cubes acting as biomass carriers (P-SMF). When compared to a conventional MF (CMF) and a MF after coagulation by utilizing PACl (P-MF), better removal of nutrients, UV₂₅₄ and dissolved organic carbon (DOC) (>65%) was obtained from the P-SMF. The accumulation of biopolymers (including polysaccharides and proteins), humic substances, hydrophilic organics, and other small molecular weight (MW) organic matter in the CMF led to the most severe membrane fouling coupled with the highest pore blocking and cake resistance. Pre-coagulation was ineffective in eliminating small MW and hydrophilic organic matter. Conversely, the larger MW organics (i.e. biopolymers and humic substances), small MW organics and hydrophilic organic compounds could be removed in significantly larger quantities in the P-SMF by PACl coagulation. This was achieved via adsorption and the biodegradation by attached biomass on these sponges and by the suspended sludge. Further analyses of the microbial community indicated that the combined addition of PACl and sponges generated a high enrichment of Zoolgloea, Amaricoccus and Reyranella leading to the reduction of biopolymers, and Flexibacter and Sphingobium were linked to the degradation of humic substances. Moreover, some members of Alphaproteobacteria in the P-SMF may be responsible for the removal of low MW organics. These results suggest that the pre-coagulation process coupled with adding sponge in the MF system is a promising technology for mitigating membrane fouling.
图文摘要:

26626. 题目: Diversity in the Mechanisms of Humin Formation during Composting with Different Materials
文章编号: N19032606
期刊: Environmental Science & Technology
作者: Xintong Gao, Wenbing Tan, Yue Zhao, Junqiu Wu, Qinghong Sun, Haishi Qi, Xin-Yu Xie, Zimin Wei
更新时间: 2019-03-26
摘要: Humins (HMs) play a very important role in various environmental processes and are crucial for regulating global carbon and nitrogen cycles in various ecosystems. Composting is a controlled decomposition process accompanied by the stabilization of organic solid waste materials. During composting, active fractions of organic substances can be transformed into HMs containing stable and complex macromolecules. However, the structural heterogeneity and formation mechanisms of HMs during composting with various substrates have not been clarified. Here, the structure and composition of HMs extracted from livestock manure (LM) and straw (SW) during composting were investigated by excitation–emission matrices spectroscopy and Fourier transform infrared spectroscopy. The results showed that the stability and humification of LM-HM were lower than that of SW-HM. The parallel factor analysis components of the HM in LM composting contained the same fluorescent unit, and the intermediate of cellulose degradation affected the structure of the HM from SW composting. Structural equation modeling demonstrated that low-molecular-weight compounds were key factors in humification. On the basis of the structure and key factors impacting HM, we constructed two mechanisms for the formation of HM from different composting processes. The LM-HMs from different humification processes have multiple identical fluorescent structural units, and the high humification of SW is affected by its polysaccharide constituents, which contains a fluorescent component in their skeleton, providing a basis for studying HM in composting.

26627. 题目: Glacially sourced dust as a potentially significant source of ice nucleating particles
文章编号: N19032605
期刊: Nature Geoscience
作者: Yutaka Tobo, Kouji Adachi, Paul J. DeMott, Thomas C. J. Hill, Douglas S. Hamilton, Natalie M. Mahowald, Naoko Nagatsuka, Sho Ohata, Jun Uetake, Yutaka Kondo, Makoto Koike
更新时间: 2019-03-26
摘要: Aeolian dusts serve as ice nucleating particles in mixed-phase clouds, and thereby alter the cloud properties and lifetime. Glacial outwash plains are thought to be a major dust source in cold, high latitudes. Due to the recent rapid and widespread retreat of glaciers, high-latitude dust emissions are projected to increase, especially in the Arctic region, which is highly sensitive to climate change. However, the potential contribution of high-latitude dusts to ice nucleation in Arctic low-level clouds is not well acknowledged. Here we show that glacial outwash sediments in Svalbard (a proxy for glacially sourced dusts) have a remarkably high ice nucleating ability under conditions relevant for mixed-phase cloud formation, as compared with typical mineral dusts. The high ice nucleating ability of the sediments is probably governed by the presence of small amounts of organic matter (<1 wt% organic carbon) rather than mineral components. In addition, our results from intensive field measurements and model simulations indicate that the concentrations of atmospheric ice nucleating particles over the Svalbard region are expected to be enhanced in the summertime under the influence of dust emissions from Svalbard and its surroundings. We suggest that high-latitude dust sources have the potential to significantly influence glaciation of Arctic low-level clouds.

26628. 题目: Unifying soil organic matter formation and persistence frameworks: the MEMS model
文章编号: N19032604
期刊: Biogeosciences
作者: Andy D. Robertson, Keith Paustian, Stephen Ogle, Matthew D. Wallenstein, Emanuele Lugato, M. Francesca Cotrufo
更新时间: 2019-03-26
摘要: Soil organic matter (SOM) dynamics in ecosystem-scale biogeochemical models have traditionally been simulated as immeasurable fluxes between conceptually defined pools. This greatly limits how empirical data can be used to improve model performance and reduce the uncertainty associated with their predictions of carbon (C) cycling. Recent advances in our understanding of the biogeochemical processes that govern SOM formation and persistence demand a new mathematical model with a structure built around key mechanisms and biogeochemically relevant pools. Here, we present one approach that aims to address this need. Our new model (MEMS v1.0) is developed from the Microbial Efficiency-Matrix Stabilization framework, which emphasizes the importance of linking the chemistry of organic matter inputs with efficiency of microbial processing and ultimately with the soil mineral matrix, when studying SOM formation and stabilization. Building on this framework, MEMS v1.0 is also capable of simulating the concept of C saturation and represents decomposition processes and mechanisms of physico-chemical stabilization to define SOM formation into four primary fractions. After describing the model in detail, we optimize four key parameters identified through a variance-based sensitivity analysis. Optimization employed soil fractionation data from 154 sites with diverse environmental conditions, directly equating mineral-associated organic matter and particulate organic matter fractions with corresponding model pools. Finally, model performance was evaluated using total topsoil (0–20 cm) C data from 8192 forest and grassland sites across Europe. Despite the relative simplicity of the model, it was able to accurately capture general trends in soil C stocks across extensive gradients of temperature, precipitation, annual C inputs and soil texture. The novel approach that MEMS v1.0 takes to simulate SOM dynamics has the potential to improve our forecasts of how soils respond to management and environmental perturbation. Ensuring these forecasts are accurate is key to effectively informing policy that can address the sustainability of ecosystem services and help mitigate climate change.

26629. 题目: Distribution of lignin phenols in comparison with plant-derived lipids in the alpine versus temperate grassland soils
文章编号: N19032603
期刊: Plant and Soil
作者: Shanshan Zhu, Guohua Dai, Tian Ma, Litong Chen, Dima Chen, Xiaotao Lü, Xiaobo Wang, Juntao Zhu, Yangjian Zhang, Yongfei Bai, Xingguo Han, Jin-Sheng He, Xiaojuan Feng
更新时间: 2019-03-26
摘要: Aims: As a major plant-derived soil organic carbon (SOC) component, lignin-derived phenolic compounds show varying biogeochemical characteristics compared to plant-derived lipid moieties. Comparing their distribution patterns can provide information on mechanisms governing SOC preservation and dynamics. However, the large-scale distribution pattern and stability of lignin versus plant-derived lipids are still poorly constrained. Here we investigated the distribution of lignin phenols versus plant-derived lipids in the surface soils across the alpine versus temperate grasslands of China and Mongolia. Methods: Lignin phenols were isolated by cupric oxide oxidation method and compared with the previously analyzed plant-derived lipids (cutin and suberin). A comprehensive list of environmental variables was compiled to disentangle the climatic, edaphic and vegetation influences on lignin phenols’ distribution in the soil. Results: Lignin phenols showed similar SOC-normalized concentrations in the alpine and temperate grassland soils despite a higher plant input to the latter, suggesting better lignin preservation in the cold region. However, compared with plant-derived lipids (cutin and suberin), lignin seems to be less stabilized. The variation of lipid versus lignin components is mainly related to climate (particularly aridity) in the alpine grassland soils, while the relative abundance of plant lipids and lignin phenols is more related to reactive mineral contents in the temperate grassland soils. Conclusions: Lignin contributes differentially to SOC accumulation in the alpine and temperate soils: while lignin seems to be better preserved in the cold region, lignin phenols decrease relative to other carbon components with SOC accrual in the temperate region. Overall, lignin distribution and fate may be more sensitive to carbon source variations than temperature shifts in the grasslands.

26630. 题目: A release of toxic elements from military shooting range soils as affected by pH and treatment with compost
文章编号: N19032602
期刊: Geoderma
作者: Karolina Lewińska, Anna Karczewska
更新时间: 2019-03-26
摘要: A screening part of this study examined soil enrichment in 7 potentially toxic elements: Cd, Cr, Cu, Ni, Pb, Sb and Zn, in two complexes of military shooting ranges situated in SW Poland. For those elements that pose a real threat to the environment, their release into pore water was examined more thoroughly. The highest values of geoaccumulation index Igeo, with the median values above 1.5, were found for Sb, Pb and Cu, therefore further release-oriented experiments focused on these three elements. Their maximum concentrations in soils were: 89.6, 48,400 and 1230 mg kg⁻¹, respectively. A 140-day incubation experiment was carried out with 5 strongly enriched soils treated with acid, lime and commercial green-waste compost, to illustrate the effects of pH and exogenous organic matter on the release of Sb, Pb and Cu into soil pore water. The treatment with lime and/or compost is usually believed to immobilize metals, while various authors reported contradictory effects of soil amendment with organic matter on the solubility of Sb. The present work indicated that liming can induce a release of Sb and Cu into soil pore water, and the treatment with compost can result in increased Cu and Pb solubility in alkaline conditions. The effect of immobilization observed in acid- and lime-treated soils after a prolonged incubation, was in the case of Pb and Cu explained by simple buffering rather than by aging. Long incubation with compost ensured immobilization of Pb, but not necessarily of Sb and Cu. The overall effects of soil treatment with moderately mature compost on the release of Sb, Pb and Cu into pore water of shooting range soils are ambiguous, and for this reason, each case of planned application of compost to polluted soils should be preceded by a thorough experimental examination.

26631. 题目: Palmitone as a potential species-specific biomarker for the crop plant taro (Colocasia esculenta Schott) on remote Pacific islands
文章编号: N19032601
期刊: Organic Geochemistry
作者: Christiane Krentscher, Nathalie Dubois, Giorgia Camperio, Matthew Prebble, S. Nemiah Ladd
更新时间: 2019-03-26
摘要: The Pacific Island ecosystems of Remote Oceania were dramatically transformed following the arrival of humans within the last ∼3000 years, as the new settlers required technological innovations and environmental modifications to maintain their populations. These modifications included the introduction of numerous exotic species, including the important crop Colocasia esculenta Schott (taro) and the development of infrastructure suitable for its cultivation. Archeological reconstruction of C. esculenta use in the Pacific has been challenging because of the low-specificity of fossil starch granules and its limited pollen production during periods of intense cultivation. Here, we assess a lipid biomarker approach to trace C. esculenta cultivation in the past. We characterized the neutral lipid compositions of leaf samples from common cultivars and widespread indigenous species from the archipelago of Vanuatu by gas chromatography–mass spectrometry (GC−MS). The compound palmitone (hentriacontan-16-one) was a major leaf wax constituent in C. esculenta cultivar samples (mean concentration of 402 ± 63 µg/g dry wt) and was only detected in one other species, the ornamental tree Cananga odorata (175 µg/g dry wt). The structure of palmitone is favorable for its long-term stability and we demonstrate its preservation potential in a 55 cm sedimentary record from Lake Vesalea on Espiritu Santo, Vanuatu, where C. esculenta is grown today. Palmitone concentrations in this core fluctuated up to 4.1 µg/g dry wt. Our results indicate that in appropriate environmental contexts, sedimentary palmitone concentrations could be used to reconstruct C. esculenta cultivation and to provide insights about past horticultural innovations in Remote Oceania.

26632. 题目: Recycling of agro-wastes for Ganoderma lucidum mushroom production and Ganoderma post mushroom substrate as soil amendment
文章编号: N19032505
期刊: Waste Management
作者: Ferial M. Rashad, M.H. El Kattan, Hayam M. Fathy, Dalia A. Abd El-Fattah, Mahmoud El Tohamy, A.A. Farahat
更新时间: 2019-03-25
摘要: The in vitro growth of Ganoderma mycelia on six agro-wastes namely, broad bean stalks (BBS), cotton stalk (CS), maize straw (MS), rice straw (RS), sugarcane bagasse (SCB) and wheat straw (WS) supplemented with wheat bran (WB) or corn gluten (CG) was evaluated. Among the substrates used, CS appeared best followed by SCB and RS. WB showed best supplementation for mycelial growth. CO₂ emission values exhibited accurate measurements to decide the suitability of such agro-waste for growth rather than visual observations. CS+RS+SCB+WB in combination proven its superiority for in vitro growth and active spawn development substrate. In mushroom house, this particular formula proved its superiority and was on par with recommended EG formula; it gave the highest yield (195.16 g Kg⁻¹), biological efficiency (19.52%), protein (16.69%), polysaccharides (3.613%) and minerals (3433 mg/100 g). Spawn running period was the shortest in treatments inoculated with agro-waste-based spawns. With 40% biochar, days required to the complete mycelium colonization and fructification were 10.60 and 23.00, respectively. At 10% biochar, highest yields (238.40 g Kg⁻¹), biological efficiencies (23.84%), protein (19.58%) and minerals (4092 mg/100 g) were obtained. The higher the biochar level, the higher the reduction in emitted CO₂, the loss in C and the increase in N of Ganoderma post mushroom substrates (GPMSs). Under greenhouse conditions, almost all the tested GPMSs, at 0.125 or 0.25%, encouraged the reproduction of reniform nematodes and improved plant growth criteria.

26633. 题目: Vertical distribution of Microbial Communities abundance and biomass in two NW Mediterranean Sea submarine canyons
文章编号: N19032504
期刊: Progress in Oceanography
作者: Tommaso Diociaiuti, Fabrizio Bernardi Aubry, Serena Fonda Umani
更新时间: 2019-03-25
摘要: The aim of the present study was to investigate the microbial community along the Ligurian coast corresponding to two marine canyons. The study considered pico-, nano- and micro-planktonic fractions, their abundances and composition. Temperature and salinity profiles along the water column showed the same trend at all stations and no significant difference was found among stations of the canyons’ profiles and those of the adjacent slope. A similar trend for abundances and biomasses was observed at all stations: higher values were generally measured at surface and decreased with increasing depth; significant linear regression was highlighted in each of the three transects. Results of the distribution of all microbial heterotrophs from the surface down to 2500 m indicate that prey abundance was generally higher than the feeding threshold of predators; this evidence suggests that the interaction between different size classes is bottom-up regulated in the study area.The slight decrease of the ratio Heterotrophic Bacteria (HB) vs. Heterotrophic NanoFlagellates (HNF) and the weak increase of relative abundance of larger HNF size classes should be the sole evidence of the expected “canyon effect”, and can be ascribed to the major input at the bottom of the canyon of particulate organic matter (POC) that can be used by heterotrophic nanoflagellates directly as a food source. Our results highlighted that the main pattern regulating community composition is depth, and that, in the aphotic layer, the different water masses (WM) present along the column, play a pivotal role in shaping the planktonic assemblage.

26634. 题目: Form of nitrogen deposition affects soil organic matter priming by glucose and cellulose
文章编号: N19032503
期刊: Biology and Fertility of Soils
作者: Peng Tian, Kyle Mason-Jones, Shengen Liu, Qingkui Wang, Tao Sun
更新时间: 2019-03-25
摘要: To examine the interplay of C and N availability, glucose (high microbial availability) and cellulose (low microbial availability) were added to soils collected from a temperate forest that had received simulated N deposition for 6 years (organic and/or inorganic N). The priming effect was higher for glucose addition than for cellulose. N deposition decreased the priming effect of easily available glucose but increased the priming effect of cellulose. This confirmed an interactive effect of fresh organic matter (FOM) availability and N deposition on priming. Furthermore, the interactive effect was affected by the form of N deposition, with interaction mainly observed with organic N deposition. Qualitatively different patterns of priming were observed for the two FOM types and were accompanied by contrasting abundance of fungi and bacteria in the community, as determined by phospholipid fatty acid (PLFA) analysis. Organic N deposition increased bacterial biomass but decreased the intensity of priming. In contrast, a competitive advantage of fungi with respect to organic N sources may drive priming by cellulose. The results highlighted the importance of the availability of FOM in regulating the priming effect and showed that interactions between the form of N deposition and the availability of the FOM should be considered when predicting soil C cycling in scenarios of increased N deposition. Organic N deposition had a greater impact on priming effects than inorganic N deposition, and the influence of microbial availability of FOM largely depended on organic N deposition.

26635. 题目: Novel soil remediation technology for simultaneous organic pollutant catalytic degradation and nitrogen supplementation
文章编号: N19032502
期刊: Chemical Engineering Journal
作者: Qincheng Chen, Pinhua Rao, Zhiwen Cheng, Lili Yan, Shiying Qian, Rui Song, Guoqing Shen
更新时间: 2019-03-25
摘要: This study developed a novel remediation technology based on urea-hydrogen peroxide (UHP) activated by a synthesized Fe-impregnated biochar (FB). The technology can simultaneously degrade sulfamethoxazole (SMZ) and supply nitrogen nutrition in cropland soil. Experimental results showed that 97.56% of SMZ was removed in the FB-UHP system within 24 h, whereas 7.12% and 14.65% were removed in the individual application of FB and UHP. Chemical probe and scavenger test results demonstrated that SMZ degradation mainly occurred through oxidation of hydroxyl radicals generated from the activation of UHP by FB. The effects of FB pyrolysis temperature, initial pH, and reaction temperature were investigated. The combination of UHP and FB led to efficient SMZ degradation at a wide pH range of 2–10. Catalytic durability test results showed that FB exhibited good stability even after four uses. A soil column leaching experiment showed that the addition of FB-UHP reduced the SMZ leaching from the soil by 95.06%, increased the nitrogen content on surface soil by approximately 2.5 times, and decreased the nitrogen leaching by 97.57%. Early-stage seedling growth bioassay confirmed that FB-UHP significantly enhanced the SMZ degradation, increased the soil nitrogen content, and improved the lettuce plant growth. Therefore, application of FB-activated UHP is a promising technology for agricultural soil remediation.
图文摘要:

26636. 题目: Efficient Treatment of Oil Sands Produced Water: Process Integration Using Ion Exchange Regeneration Wastewater as a Chemical Coagulant
文章编号: N19032501
期刊: Separation and Purification Technology
作者: Farshad Mohammadtabar, Rajesh G. Pillai, Behnam Khorshidi, Armin Hayatbakhsh, Mohtada Sadrzadeh
更新时间: 2019-03-25
摘要: The potential of ion exchange regeneration wastewater (IERW) containing magnesium ions to act as a coagulant for steam-assisted gravity drainage (SAGD) boiler blowdown (BBD) water was investigated with the aim of reducing the water consumption in a SAGD plant. Conventional techniques for the treatment of BBD water require significant operational costs as they rely on the extensive use of chemical coagulants or electric power. Since the proposed process design in this study uses a wastewater stream for the treatment of the BBD water, operational costs and energy consumption are predicted to be minimized. The effect of temperature, the mixing ratio of BBD and the IERW water, and the stirring intensity on the removal of organic matter and dissolved minerals were investigated. Usage of IERW as the coagulant enhanced the removal of impurities; removal efficiency of 81.1% and 98.6% were obtained for organic matter and silica concentration, respectively. The treatment of BBD water by IERW, however, has led to an increase in the concentration of calcium in the effluent, which was effectively mitigated by soda ash softening. Furthermore, resource recovery from the coagulated sludge was explored by SEM, EDX, FTIR, XPS, and XRD, and revealed that the precipitated compounds were mostly composed of calcium, magnesium, and silica. Additionally, the successful usage of IERW for the treatment of another BBD wastewater with a higher concentration of organic matter was demonstrated. In conclusion, the IERW water proved to be highly effective in removing contaminants from SAGD produced water.

26637. 题目: Sediment information on natural and anthropogenic-induced change of connected water systems in Chagan Lake, North China
文章编号: N19032412
期刊: Environmental Geochemistry and Health
作者: Wei Guo, Yunkai Wang, Jianghong Shi, Xu Zhao, Yangcun Xie
更新时间: 2019-03-24
摘要: This study discusses changes in connected water systems in Chagan Lake induced by the interference of natural and human activities, based on the analysis of sediment characteristics. In this study, the following sediment characteristics were investigated in the lake area, the natural supply area, and the lake drainage area: mineral composition; particle size distribution; magnetic susceptibility; nutrient content; content of isotopes δ13Corg and δ15N; and content of heavy metals and of metallic oxides. The results showed that silicate minerals quartz, orthoclase, and anorthose were abundant in the whole lake water system. Quartz accumulated more easily in the lake area, while carbonate masses in the lake mainly came from the Huolinhe River. Moving from the lake area to the water diversion and drainage areas, fine particles clearly decreased, while coarse particles significantly increased due to the increase in hydraulic erosion. The main sources of nutrients and of organic matter are: the residual of the drainage from the Qianguo irrigated areas; the surrounding villages and the tourist area; and the decomposition of aquatic organisms. A large number of anthropogenic heavy metals, such as Hg, Cu, and As, were accumulated in the artificial water diversion area and in the farmland drainage area. This study indicates that recovering the original connected water system during the wet season, while at the same time enhancing water supply during the dry season could improve the ecological quality of Chagan Lake.

26638. 题目: Influences of carbon and nitrogen sources and metal ions on the heterotrophic culture of Scenedesmus sp. LX1
文章编号: N19032411
期刊: Environmental Science and Pollution Research
作者: Yitian He, Yu Hong, Xiaoya Liu, Qing Zhang, Peirui Liu, Shaoyun Wang
更新时间: 2019-03-24
摘要: In this study, the influences of organic carbon sources (OCS, including xylose, glucose, maltose, sucrose, and starch) and inorganic and organic nitrogen sources (INS, including ammonia chloride and sodium nitrate; ONS, including arginine, alanine, proline, and valine) and metal ions (including Na⁺, K⁺, Mn²⁺, Zn²⁺ and Cu²⁺) on the growth, lipid accumulation, and nitrogen and phosphorus (N&P) removal capabilities of oleaginous Scenedesmus sp. LX1 under heterotrophic conditions were investigated. The results showed that glucose was the only OCS for Scenedesmus sp. LX1 to grow well with specific growth rate of 0.935 days⁻¹, maximum biomass of 1.72 g L⁻¹, and largest removal rates of N&P and organic carbon reaching 72.228%, 93.034%, and 19.208%, respectively. After 11 days of cultivation, the maximal biomass reached in the group with starch or glucose while maximal lipid and triacylglycerol (TAG) yields reached in the groups with maltose and sucrose, respectively. Sodium nitrate was best nitrogen source as the largest algal density, maximal yields of lipids and TAGs, and highest N&P removal rates reached up to 1.105 × 10⁷ cells·mL⁻¹, 196.70 mg L⁻¹, 5.19 mg L⁻¹, 89.61% and 100%, respectively. Scenedesmus sp. LX1 was found to have great tolerance to Na⁺, K⁺, Mn²⁺, and Zn²⁺ while 0.5 mg L⁻¹ Cu²⁺ had a strong inhibition on growth and N&P removal rate of Scenedesmus sp. LX1. Concentration increasing of five metal ions all caused the yield increases of microalgal lipid and TAGs.

26639. 题目: Diverse mycorrhizal associations enhance terrestrial C storage in a global model
文章编号: N19032410
期刊: Global Biogeochemical Cycles
作者: Benjamin N. Sulman, Elena Shevliakova, Edward R. Brzostek, Stephanie N. Kivlin, Sergey Malyshev, Duncan N.L. Menge, Xin Zhang
更新时间: 2019-03-24
摘要: Accurate projections of the terrestrial carbon (C) sink are critical to understanding the future global C cycle and setting CO2 emission reduction goals. Current earth system models (ESMs) and dynamic global vegetation models (DGVMs) with coupled carbon‐nitrogen cycles project that future terrestrial C sequestration will be limited by nitrogen (N) availability, but the magnitude of N limitation remains a critical uncertainty. Plants use multiple symbiotic nutrient acquisition strategies to mitigate N limitation, but current DGVMs omit these mechanisms. Fully coupling N‐acquiring plant‐microbe symbioses to soil organic matter (SOM) cycling within a DGVM for the first time, we show that increases in N acquisition via SOM decomposition and atmospheric N2 fixation could support long‐term enhancement of terrestrial C sequestration at global scales under elevated CO2. The model reproduced elevated CO2 responses from two experiments (Duke and Oak Ridge) representing contrasting N acquisition strategies. N release from enhanced SOM decomposition supported vegetation growth at Duke, while inorganic N depletion limited growth at Oak Ridge. Global simulations reproduced spatial patterns of N‐acquiring symbioses from a novel niche‐based map of mycorrhizal fungi. Under a 100 ppm increase in CO2 concentrations, shifts in N acquisition pathways facilitated 200 Pg C of terrestrial C sequestration over 100 years compared to 50 Pg C for a scenario with static N acquisition pathways. Our results suggest that N acquisition strategies are important determinants of terrestrial C sequestration potential under elevated CO2, and that nitrogen‐enabled DGVMs that omit symbiotic N acquisition may underestimate future terrestrial C uptake.

26640. 题目: Fast aniline and nitrobenzene remediation from water on magnetized and nonmagnetized Douglas fir biochar.
文章编号: N19032409
期刊: Chemosphere
作者: Narada Bombuwala Dewage, Achala S. Liyanage, Quanisha Smith, Charles U. Pittman, Felio Perez, El Barbary Hassan, Dinesh Mohan, Todd Mlsna
更新时间: 2019-03-24
摘要: Magnetic biochar (MBC) was prepared by the dispersion of α-Fe₂O₃ and Fe₃O₄ particles on high surface area (663 m²/g) Douglas fir biochar (BC). The BC was impregnated with FeCl₃ and pyrolyzed at 600 °C under N₂ to produce (494 m²/g) MBC. Both BC and MBC biochars were used for removal of aniline and nitrobenzene from water. MBC and its precursor BC were characterized using scanning electron microscopy (SEM), energy dispersive X-ray analysis (SEM-EDX), transmission electron microscopy (TEM), surface area analysis (Brunauer-Emmett-Teller isotherm) (S_BET), point of zero charge (PZC), X-ray powder diffraction (XDR), elemental analysis, and X-ray photoelectron spectroscopy (XPS). Batch sorption studies were carried out from pH 2–12 and both aniline and nitrobenzene adsorption on MBC and BC remained high and unchanged over the entire pH range. Sorption was evaluated using the Langmuir and Freundlich isotherm models. Langmuir adsorption capacities on BC and MBC (pH 7, 25 °C) were 360 mg/g and 338 mg/g for aniline and 193 mg/g and 178 mg/g for nitrobenzene, respectively.
图文摘要: