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24721. 题目: Carbon outwelling and outgassing vs. burial in an estuarine tidal creek surrounded by mangrove and saltmarsh wetlands
文章编号: N19010305
期刊: Limnology and Oceanography
作者: Isaac R. Santos, Damien T. Maher, Reece Larkin, Jackie R. Webb, Christian J. Sanders
更新时间: 2019-01-03
摘要: Mangrove‐ and saltmarsh‐dominated estuaries have high rates of organic carbon burial. Here, we estimate soil, pore water, and surface‐water carbon fluxes in an Australian estuarine tidal creek to assess whether (1) advective pore water exchange releases some of the soil carbon, (2) outwelling (lateral exports) represents a major carbon sequestration mechanism, and (3) methane emissions offset soil carbon sequestration. A radon (222Rn) mass balance implied tidally driven pore‐water exchange rates ranging from 5.5 ± 3.6 to 15.6 ± 8.1 cm d−1. Pore water exchange explained most of the dissolved organic carbon (DOC) and methane surface‐water fluxes but not dissolved inorganic carbon (DIC) and alkalinity. Organic carbon burial in soils derived from 239 + 240Pu dating was 11–63 g C m−2 yr−1. Methane and carbon dioxide emissions at the water–air interface were 0.27 ± 0.03 and 63 ± 166 mmol m−2 d−1, respectively. When calculated as CO2‐equivalents, aquatic CH4 emissions converted to 19–94 g C‐CO2 m−2 yr−1. Upscaling methane and soil carbon fluxes to representative areas revealed that CH4 emissions could offset < 5% of soil carbon burial. DIC outwelling (12 ± 6 mmol m−2 catchment d−1) was less than five‐fold greater than DOC and particulate organic carbon (POC) outwelling and four‐fold greater than catchment‐wide carbon burial. Because much of this DIC remains in the ocean after air–water equilibration, lateral DIC exports may represent an important long‐term carbon sink. Recent research has focused on quantifying carbon burial rates in blue carbon habitats such as saltmarshes and mangroves. We suggest that DIC outwelling and methane outgassing should also be considered when assessing the carbon sequestration capacity of these coastal vegetated habitats.
24722. 题目: Effects of sludge lysate for Cr(VI) bioreduction and analysis of bioaugmentation mechanism of sludge humic acid
文章编号: N19010304
期刊: Environmental Science and Pollution Research
作者: Hongling Chen, Ruofei Jin, Guangfei Liu, Tian Tian, Chen Gu, Jiti Zhou, Defeng Xing
更新时间: 2019-01-03
摘要: This study evaluated the effects of sludge lysate (SL) on the anaerobic bioreduction of Cr(VI) and the role of sludge humic acid (SHA) during this process. The results showed that supplement of SL significantly enhanced the efficiency of Cr(VI) bioreduction by 29.61%, in 12 h compared with that of the control without SL. Moreover, SHA exhibited promoting effects on bioreduction of Cr(VI), and the promotion increased with increasing SHA concentrations from 100 to 300 mg/L. In the presence of 300 mg/L SHA, Cr(VI) (98.21 mg/L) was completely reduced after 24 h with a removal rate increased by 34.3% compared with that of the control without SHA. Further investigation on the bioaugmentation mechanism of SHA by studying the nature of SHA and the reaction mechanism between SHA and Cr(VI) revealed that SHA exhibited a strong adsorption ability, which could adsorb and combine with Cr(VI). The adsorption capacity of Cr(VI) by SHA was calculated as 34.4 mg/g with 0.2 g of SHA and 10 mg/L of Cr(VI). It could also act as redox mediators to accelerate the electron transfer between microorganisms and Cr(VI) to promote reduction of Cr(VI). Furthermore, the effects of SL on the microbial community compositions of the anaerobic Cr(VI) bioreduction system were studied. Brachymonas was the primary bacteria at the genus level. The abundance of electroactive bacteria, such as Acinetobacter, Pseudomonas, and Arcobacter, increased in the SL-amended system. These findings expand the versatility of SL and justify wider use of residual activated sludge, which might contribute to the treatment of heavy metal–contaminated wastewater.
24723. 题目: Organic signatures in Pleistocene cherts from Lake Magadi (Kenya), analogs for early Earth hydrothermal deposits
文章编号: N19010303
期刊: Biogeosciences
作者: Manuel Reinhardt, Walter Goetz, Jan-Peter Duda, Christine Heim, Joachim Reitner, and Volker Thiel
更新时间: 2019-01-03
摘要: Organic matter in Archean hydrothermal cherts may provide an important archive for molecular traces of earliest life on Earth. The geobiological interpretation of this archive, however, requires a sound understanding of organic matter preservation and alteration in hydrothermal systems. Here we report on organic matter (including molecular biosignatures) enclosed in hydrothermally influenced cherts of the Pleistocene Lake Magadi (Kenya; High Magadi Beds and Green Beds) – important analogs for Archean cherts. The Magadi cherts contain low organic carbon (<0.4wt.%) that occurs in form of finely dispersed clots, layers, or encapsulated within microscopic carbonate rhombs. Both, extractable (bitumen) and non-extractable organic matter (kerogen) was analyzed. The bitumens contain immature biolipids
like glycerol mono- and diethers (e.g., archaeol and extended archaeol), fatty acids and – alcohols indicative for, inter alia, thermophilic cyanobacteria, sulfate reducers, and haloarchaea. However, co-occurring geolipids
such as n-alkanes, hopanes, and polycyclic aromatic hydrocarbons (PAHs) indicate that a fraction of the bitumen has been thermally altered to early or peak oil window maturity. This more mature fraction likely originated from defunctionalization of dissolved organic matter and/or hydrothermal petroleum formation at places of higher thermal flux. Like the bitumens, the kerogens also show variations in thermal maturities, which can partly be explained by admixture of thermally pre-altered macromolecules. However, findings of archaea-derived isoprenoid moieties in some of the kerogens indicate that a fast sequestration of microbial lipids into kerogen must have occurred while hydrothermal alteration was active. We posit that such early sequestration may enhance the survival of molecular biosignatures during in-situ hydrothermal (and post-depositional) alteration through deep time. Furthermore, the co-occurrence of organic matter with different thermal maturities in the Lake Magadi cherts suggests that similar findings in Archean hydrothermal deposits could partly reflect original environmental conditions, and not exclusively post-depositional overprint or contamination. Our results support the view that kerogen in Archean hydrothermal cherts may contain important information on early life. Our study also highlights the suitability of Lake Magadi as an analog system for hydrothermal chert environments on the Archean Earth.
24724. 题目: Review of biochar for the management of contaminated soil: Preparation, application and prospect
文章编号: N19010302
期刊: Science of The Total Environment
作者: Peng Yuan, Jianqiao Wang, Yijun Pan, Boxiong Shen, Chunfei Wu
更新时间: 2019-01-03
摘要: As a multi-beneficial amendment, biochar is reasonable and reliable to be employed as an amendment to implement soil remediation. An overview on the manufacture, applications for contaminated soil restoration and revegetation, as well as recommended aspects for future work has been accomplished. One of the objectives of this work presented herein was to determine the effect of feedstock and preparation conditions such as pyrolysis temperature, retention time, gas flow rate, additives on the biochar characteristics and application potentials. Besides, relevant modification or activation technologies have been discussed for the improvement of the biochar functions. The application of biochar could adjust the soil structure (surface area, pore size and distribution etc.), improve the soil physicochemical properties (pH, cation exchange capacity, water retention capacity etc.) and enhance the uptake of soil nutrients for plant growth; In addition, it also can be used to adsorb various contaminants (heavy metals, organic matters), modify the habit and function of microorganism and mitigate climate problem by changing the bioavailability of elements (C, N, K etc.) in soil. These results also provided the possibility to expend the application of biochar to modify the degraded soils in the saline-alkali soil and industrial regions, further increase the usable area of cultivated land. The future research directions could be suggested as long-term field trials, the evaluation of environmental risk and the optimization of biochar production. Moreover, the relevant mechanisms should be adequately considered for maximizing the all-around efficiency of biochar amendments.
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24725. 题目: Manure pellet, woodchip and their biochars differently affect wheat yield and carbon dioxide emission from bulk and rhizosphere soils
文章编号: N19010301
期刊: Science of The Total Environment
作者: Prem Pokharel, Scott X. Chang
更新时间: 2019-01-03
摘要: Application of biochars produced by pyrolyzing organic residues to cropland has been proposed to be an effective approach to better use of organic residues, decrease soil greenhouse gas emission and increase soil fertility. However, the effect of biochar application on processes occurring in the bulk soil vs that in the rhizosphere is poorly understood. This study investigated the effects of manure pellet and woodchip biochars, as compared to that of unpyrolyzed (raw) manure pellet and woodchip, on plant grain yield, and soil respiration in the bulk and rhizosphere soils in a greenhouse experiment using the rhizobox technique. The raw manure pellet and woodchip and their biochars were applied to the soil at the rate of 57 t ha−1 and spring wheat (Triticum aestivum L. var. GP168) was grown in the rhizosphere compartment of the rhizobox. Soil amendment with raw manure pellet and its biochar significantly increased plant grain yield by 36.3 and 16.1%, as compared to the control (without amendment), while raw woodchip and its biochar applications significantly decreased plant grain yield. Manure pellet and woodchip biochars significantly reduced soil respiration from the rhizosphere by 24.6 and 29.7%, respectively, relative to the control, but not that from the bulk soil (P > 0.05). Relativized cumulative CO2 emission was significantly reduced by both manure pellet and woodchip biochars from rhizosphere and bulk soils. Dissolved organic carbon and nitrogen were increased (P < 0.01) in all soil amendment treatments in both bulk and rhizosphere soils, but microbial biomass carbon and nitrogen in the rhizosphere soil were reduced by manure pellet biochar application. We conclude that biochars produced from organic residues have differential impacts on processes in bulk and rhizosphere soils, and thus measurements based on bulk soil alone may result in erroneous conclusions about the effect of biochars on soil CO2 emission.
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24726. 题目: Glucose and ribose stabilization in soil: Convergence and divergence of carbon pathways assessed by position-specific labeling
文章编号: N19010213
期刊: Soil Biology and Biochemistry
作者: Ezekiel K. Bore, Yakov Kuzyakov, Michaela A. Dippold
更新时间: 2019-01-02
摘要: Transformation of sugars by microorganisms is a key process influencing carbon (C) stabilization in soil. To reveal the mechanisms responsible for the persistence of labile C in soil, the fates of position-specific and uniformly 13C labeled glucose and ribose were studied under field conditions for 800 days. We hypothesized a convergence of the fate of individual C positions and substances because of the long-term C recycling by microorganisms.Position-specific data revealed that both sugars were simultaneously metabolized via glycolysis and the pentose phosphate pathway (PPP). The position-specific 13C recovery pattern in soil and in microbial biomass was similar. This similarity demonstrated significant contribution of microbial products and necromass to soil organic matter (SOM) formation. Based on a biexponential model, the mean residence times (MRTs) of glucose C-6 and ribose C-5 in the soil were longer than the other C positions. However, the MRT of uniformly labeled 13C from ribose in the soil was 3 times longer than that from glucose. Consequently, ribose and glucose were incorporated into different cellular components, defining their long-term fate in soil. The convergence of glucose C positions in soil and microbial biomass revealed that recycling and modification of recycled components dominated glucose transformation. In contrast, divergence of ribose C positions in soil revealed that intact ribose-derived cell components are reused or preserved in SOM.Thus, convergence versus divergence of individual C positions distinguished the two key stabilization mechanisms explaining the long persistence of C from easily available sources in the soil: sustained microbial recycling (convergence) versus preservation (divergence) in long-term stabilized compound classes.
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24727. 题目: Temporal variability of metallic properties during flood events in the Deba River urban catchment (Basque Country, Northern Spain) after the introduction of sewage treatment systems
文章编号: N19010212
期刊: Environmental Earth Sciences
作者: Jon García-García, Estilita Ruiz-Romera, Miren Martínez-Santos, Iñaki Antigüedad
更新时间: 2019-01-02
摘要: The aim of this study was to assess the particulate metal pollution status and the evolution of particulate metal contamination after the implementation of sewage treatment systems in the Deba River catchment during flood events. Concentrations of suspended particulate matter (SPM), dissolved (DOC) and particulate (POC) organic carbon and metals (Fe, Mn, Zn, Ni, Cu, Cr and Pb) were monitored in the urban watershed over four hydrological years. Geoaccumulation index was used to determine the pollution degree and a number of statistical analyses were performed to elucidate temporal changes. 14 flood events were analyzed from October 2011 to September 2015. The content of metals (Fe, Mn, Zn, Ni, Cr, Cu and Pb) in suspended solids showed a high degree of temporal variability which depended on number of factors being the hydrodynamic process the main one controlling the behaviour of particulate metals. Zn, Ni Cr and Cu appear to be mainly related to anthropogenic sources, whereas Pb appears to be lithogenic in character (like Fe) possibly related to an ageing process. The decrease of metal pollution degree and the homogenisation of organic and metal sources could be a consequence of the wastewater treatment, despite it seems likely that this will be a long-term process.
24728. 题目: Modelling tool to assess membrane regeneration by periodical hydraulic cleaning and fouling control in pressurized membrane process for surface water treatment
文章编号: N19010211
期刊: Environmental Earth Sciences
作者: Amine Charfi, Hoseok Jang, Jeonghwan Kim
更新时间: 2019-01-02
摘要: In this study, a mathematical model was developed to assess fouling as well as membrane regeneration in a pressurized, hollow-fiber membrane system for the treatment of highly turbid surface water using periodical cleaning by backwashing and forward flushing. The model was validated using experimental data of trans-membrane pressure obtained when filtering separately, a SiO2 solution, a mixed SiO2/sodium alginate (SA) solution, a mixed SiO2/bovin serum albumin (BSA) solution and a mixed SiO2/humic acid (HA). Experimental and theoretical studies highlighted the synergistic fouling effect between SiO2 simulating the colloidal particles and the different elements (HA, SA and BSA) simulating the natural organic matter. Protein fouling was mitigated when mixed with SiO2. While the highest fouling rate was obtained for mixed SiO2/SA solution, the majority of this fouling was removed by periodic cleaning. Moreover, mixed SiO2/HA solution showed also high fouling which was mainly irreversible.
24729. 题目: Factors Influencing Inhibitory Effect of Alginic Acid on the Growth Rate of Struvite Crystals
文章编号: N19010210
期刊: Water, Air, & Soil Pollution
作者: Lin Wei, Tianqiu Hong, Tianhu Chen, Xiaoyang Li, Qiang Zhang
更新时间: 2019-01-02
摘要: Phosphorus-rich sludge is one of most suitable raw materials for phosphorus recovery as slow release fertilizers by struvite crystallization. However, alginic acid as a surrogate for extracellular polymeric substances in the sludge has been proved to adversely inhibit struvite crystallization. To quantitatively evaluate the inhibitory effect, the study aimed to investigate the influence of the concentration of alginic acid (0–250 mg/L), reactant concentration (2.5–3.5 mmol/L), pH (8.0–9.5), and ionic strength (0.01–0.2 mol/L NaCl), on the inhibition of the growth rate of struvite crystals, which was accurately determined by constant composition technique. The results indicated that the growth rate of struvite crystals substantially decreased with increasing the concentration of alginic acid, thereby adversely affecting the quantity and quality of struvite crystals. Moreover, as reactant concentration or pH increased, the growth rate of struvite crystals showed a considerable increase, whereas the weaker inhibitory effect of alginic acid was observed. Conversely, the increase of ionic strength drastically reduced the growth rate of struvite crystals, but moderately enhanced the inhibitory effect. Our study provides an effective theoretical foundation for deriving high-quality struvite crystals as slow release fertilizers from the phosphorus-rich sludge commonly containing a considerable number of organic pollutants.
24730. 题目: Ecological stoichiometry characteristics of the leaf–litter–soil continuum of Quercus acutissima Carr. and Pinus densiflora Sieb. in Northern China
文章编号: N19010209
期刊: Environmental Earth Sciences
作者: Jianni Sun, Peng Gao, Cheng Li, Rongjia Wang, Xiang Niu, Bing Wang
更新时间: 2019-01-02
摘要: To research the nutrient circulation laws of the pine-oak forest ecosystem, this paper studied the ecological stoichiometry characteristics of organic carbon (C), total nitrogen (N) and total phosphorus (P) in the two “leaf–litter–soil” continuums (QAC: Quercus acutissima Carr., PDS: Pinus densiflora Sieb.) in China and their intrinsic relationships. Results showed that (1) Contents of C, N and P in the two continuums were C > N > P, and total contents of the different components were leaf > litter > soil. (2) Ecological stoichiometry characteristics of C, N and P in the two continuums were C:P > C:N > N:P. For the different components, the C:N and C:P were litter > leaf > soil, and the N:P was leaf > litter > soil. (3) Content of C in leaves was higher than that of the global and Chinese values and indicated that their defense capabilities against outside environmental forces were very strong. While contents of N and P in soil were lower than that of the global and Chinese values. Therefore, attention should be paid to selecting nitrogen fixing species and strengthening the construction of a mixed forest in mountainous area of northern China and similar areas around the world.
24731. 题目: Investigating responses of soil bacterial community composition to hardwood biochar amendment using high-throughput PCR sequencing
文章编号: N19010208
期刊: Applied Soil Ecology
作者: Emily J. Cole, Omid R. Zandvakili, Jeffrey Blanchard, Baoshan Xing, Masoud Hashemi, Fatemeh Etemadi
更新时间: 2019-01-02
摘要: The objectives of this field study were to evaluate the influence of sugar maple hardwood biochar on soil bacterial communities using next-generation sequencing via the Illumina MiSeq platform. Bacterial communities were sampled in soils with application rates of biochar including a control of 0%, 2% and a high rate of 4% by weight three years after incorporation of biochar. Bacterial 16S rRNA (V4 region) was sequenced using the Illumina MiSeq platform and identified using the SILVA database. Overall, the changes in the microbial communities with the addition of biochar were modest, potentially indicating an overall temporal-stability of diverse microbial communities in soil after biochar amendment. While individual taxa were significantly affected, including N-Cycling bacteria, there was no overall significant difference in total abundance, observed OTUs or alpha diversity indices.
24732. 题目: Cr(VI) removal from aqueous solution using biochar modified with Mg/Al-layered double hydroxide intercalated with ethylenediaminetetraacetic acid
文章编号: N19010207
期刊: Bioresource Technology
作者: Danlian Huang, Caihong Liu, Chen Zhang, Rui Deng, Rongzhong Wang, Wenjing Xue, Hao Luo, Guangming Zeng, Qing Zhang, Xueying Guo
更新时间: 2019-01-02
摘要: In this study, the bamboo biomass loaded with ethylenediaminetetraacetic acid (EDTA) intercalated Mg/Al-layered double hydroxides (LDH) was calcined to obtain a novel nano-adsorbent (BC@EDTA-LDH), and BC@EDTA-LDH was used to remove hexavalent chromium (Cr(VI)) in aqueous solutions. The results showed that the interaction between LDH and Cr(VI) on biochar played a dominant part in adsorption. The LDH of Cr(VI) intercalation was successfully reconstructed after adsorption. Fourier transform infrared spectra and X-ray diffraction results confirmed the reconstruction of Mg/Al-LDH. LDH had sustained release effect on the solution. As the pH values increased, the electrostatic repulsion between Cr2O72- and OH- increased, and there existed competition for adsorption sites. The maximum adsorption capacity of Cr(VI) was 38 mg/g. The data was well-fitted with pseudo second-order model and Langmuir-Freundlich model. BC@EDTA-LDH showed a high adsorption capacity and was potentially suitable for removing heavy metals in wastewater.
24733. 题目: Organic carbon content drives methylmercury levels in the water column and in estuarine food webs across latitudes in the Northeast United States
文章编号: N19010206
期刊: Environmental Pollution
作者: V.F. Taylor, K.L. Buckman, E.A. Seelen, N.M. Mazrui, P.H. Balcom, R.P. Mason, C.Y. Chen
更新时间: 2019-01-02
摘要: Estuaries are dynamic ecosystems which vary widely in loading of the contaminant methylmercury (MeHg), and in environmental factors which control MeHg exposure to the estuarine foodweb. Inputs of organic carbon and rates of primary production are important influences on MeHg loading and bioaccumulation, and are predicted to increase with changes in climate and land use pressures. To further understand these influences on MeHg levels in estuarine biota, we used a field study approach in sites across different temperature regions, and with varying organic carbon levels. In paired comparisons of sites with high vs. low organic carbon, fish had lower MeHg bioaccumulation factors (normalized to water concentrations) in high carbon sites, particularly subsites with large coastal wetlands and large variability in dissolved organic carbon levels in the water column. Across sites, MeHg level in the water column was strongly tied to dissolved organic carbon, and was the major driver of MeHg concentrations in fish and invertebrates. Higher primary productivity (chlorophyll-a) was associated with increased MeHg partitioning to suspended particulates, but not to the biota. These findings suggest that increased inputs of MeHg and loss of wetlands associated with climate change and anthropogenic land use pressure will increase MeHg concentrations in estuarine food webs.
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24734. 题目: Dissolved organic matter characterization of biochars produced from different feedstock materials
文章编号: N19010205
期刊: Journal of Environmental Management
作者: Anushka Upamali Rajapaksha, Yong Sik Ok, Ali El-Naggar, Hyojeon Kim, Fanhao Song, Seoktae Kang, Yiu Fai Tsang
更新时间: 2019-01-02
摘要: Fluorescence excitation-emission matrix (EEM) spectroscopy coupled with parallel factor analysis (PARAFAC) enables better understanding of the nature of dissolved organic matter (DOM). In the current study, we characterized 10 biochar samples produced from different feedstocks using EEM/PARAFAC analysis. The composition and distribution of DOM substances present in biochar varied significantly according to feedstock, activation, and pyrolysis temperature. The integration of proximate and ultimate analyses of the solid phase together with water extractable organic matter (WEOM) phase of biochar provided new insights into the characterization of biochars, including nature and functionality. Characterization of both WEOM and solid phases is recommended for biochar research before large-scale production for various environmental and industrial applications.
24735. 题目: Effect of silver nanoparticles on an integrated fixed-film activated sludge–sequencing batch reactor: Performance and community structure
文章编号: N19010204
期刊: Journal of Environmental Sciences
作者: Hexi Zhou, Guoren Xu
更新时间: 2019-01-02
摘要: The effects of silver nanoparticles (AgNPs) on reactor performance, extracellular polymeric substances composition and microbial community structure and function in integrated fixed-film activated sludge–sequencing batch reactors (IFAS–SBRs) were investigated. Results showed that the addition of AgNPs from 0.1 to 10 mg/L exhibited no significant effects on nutrient removal. The average overall removal of COD, NH4+–N and PO43−–P was 96.6%, 99.9% and 98.8%, respectively. The introduction of AgNPs caused an increase in extracellular polymeric substances content for the sludge and biofilm of IFAS–SBRs. The release of Ag+ from AgNPs and lactate dehydrogenase test implied the low toxicity of AgNPs to IFAS–SBRs. High-throughput sequencing revealed that microbial community structure showed significant shifts at phylum and genus levels after long-term exposure to AgNPs, but core functional groups responsible for nutrient removal remained at high abundance. Bacterial function prediction indicated that the metabolic categories showed no significant shifts under AgNPs stress, therefore good process performance could still be achieved.
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24736. 题目: Precipitation of calcium sulfate dihydrate in the presence of fulvic acid and magnesium ion
文章编号: N19010203
期刊: Chemical Engineering Journal
作者: Yudong Xu, Youxiang Liao, Zhenlin Lin, Jiang Lin, Qingwei Li, Jiuyang Lin, Zhengxin Jin
更新时间: 2019-01-02
摘要: The present work focused on the reduction of the calcium and sulfate ions in a membrane permeate generated from a newly developed two-stage of tight ultrafiltration (TUF) for recovering humic substance from leachate nanofiltration (NF) concentrate by a precipitation process of calcium sulfate dihydrate (gypsum). The operating parameters (temperature and pH), mechanism of precipitating behaviors, and kinetics of this process in the presence of fulvic acid (FA) and magnesium ion simultaneously were investigated. It was found that Ca2+ removal increased with increasing temperature. The decline in pH, especially towards low pH range of 2-3 around the point of zero charge of gypsum, showed a significant effect on gypsum precipitation. Adsorption of FA onto gypsum surface had an important effect on the precipitating behavior of gypsum whose mechanism might be mainly weak interactions of hydrogen bonding and hydrophobic effect at low pH, while electrostatic interactions became dominant at neutral pH. In contrast, retardation effect of Mg2+ ion on gypsum precipitation was negligible at pH 2.5. The soluble calcium removal during precipitation process corresponded with first order rate equation. The results indicated that the optimal operating parameters were found at 70 °C and around pH 2.5, which can be applied to the scale-up and industrial design of the precipitation process of gypsum for removing the calcium and sulfate ions in the presence of FA and magnesium ion.
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24737. 题目: In-situ power generation and nutrients recovery from waste activated sludge - long-term performance and system optimization
文章编号: N19010202
期刊: Chemical Engineering Journal
作者: Dan Wu, Faqian Sun, Feng Jun Desmond Chua, Dan Lu, David C. Stuckey, Yan Zhou
更新时间: 2019-01-02
摘要: This study reports an integrated sludge treatment and resource recovery system that consisted of a sludge pre-treatment reactor and a microbial fuel cell (MFC) aiming for simultaneous energy and nutrients recovery. Nearly one year performance of the system in terms of power generation, nutrients removal efficiency, key dissolved organic matters (DOMs) transformation and microbial community change were investigated and reported. Volatile fatty acids (VFAs) and other soluble organic matters was produced from fermentation of waste activated sludge under thermophilic alkaline condition. Fermented liquor (FL) was used as feed for MFC, which produced maximum voltage of 0.477 V and power density of 8.07 W m-3. Humic-like substances (HSs) were removed by 48.27% within a 5 days cycle. The analysis on DOMs transformation revealed both high and low molecular weight protein and polysaccharides, and HSs were converted and contributed to power generation. Some unknown compounds in FL could enhance the power generation by 5.5 times more compared to pure VFA as feed. 90.59% of ammonium was removed with majority concentrated in the cathode. Phosphorus was removed and stored in the biomass in the form of polyphosphate (poly-P). Microbial community analysis indicated that Exoelectrogenic was the dominant community while Aquamicrobium, Nitrosomonas, Achromobacter and Rhodocylaceae were also enriched in the anode. This work demonstrates that the integrated system can successfully remove and recover nutrients and generate power simultaneously with long-term stable performance.
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24738. 题目: Intact polar lipid and core lipid inventory of the hydrothermal vent methanogens Methanocaldococcus villosus and Methanothermococcus okinawensis
文章编号: N19010201
期刊: Organic Geochemistry
作者: Lydia M.F. Baumann, Ruth-Sophie Taubner, Thorsten Bauersachs, Michael Steiner, Christa Schleper, Jörn Peckmann, Simon K.-M.R. Rittmann, Daniel Birgel
更新时间: 2019-01-02
摘要: For the first time, a comprehensive documentation of the core and intact polar lipid composition of the hydrogenotrophic, (hyper)thermophilic, methanogenic archaea Methanocaldococcus villosus strain DSM 22612T and Methanothermococcus okinawensis strain DSM 14208T is provided. Intact polar lipids of both organisms consist almost exclusively of glycolipids. M. villosus has mainly diglycosidic and some monoglycosidic head groups. In contrast, M. okinawensis is typified by more monoglycosidic than diglycosidic head groups and some phosphoglycosidic head groups. Both strains exhibit mainly diether lipids, namely archaeol and macrocyclic archaeol, which together account for 95% of the total core lipids. M. villosus reveals more macrocyclic archaeol (55%) than archaeol (39%). In M. okinawensis the ratio is almost reversed (35% macrocyclic archaeol; 59% archaeol). Both organisms also show minor relative abundances of GDD-0 (glycerol dialkyl diether) and GMD-0 (glycerol monoalkyl diether). The two methanogens also contained minute abundances of tetraether lipids. GDGT-0 (glycerol dialkyl glycerol tetraether) was dominant and accompanied by smaller amounts of GMGT-0 (glycerol monoalkyl glycerol tetraether) and GTGT-0 (glycerol trialkyl glycerol tetraether). Two isomers of GMGT-0 occurred in both organisms, whereas one was predominant in M. villosus and the other one in M. okinawensis. The detection of macrocyclic archaeol represents the first report of this compound in the genus Methanothermococcus. GTGT-0 and GMGT-0 have so far not been described in any representative of both genera, and two isomers of GMGT-0 not in any other organism. These new observations will be instrumental for the interpretation of archaeal-derived molecular fossils in environmental samples.
24739. 题目: Long-term nitrogen addition suppresses microbial degradation, enhances soil carbon storage, and alters the molecular composition of soil organic matter
文章编号: N19010101
期刊: Biogeochemistry
作者: Jun-Jian Wang, Richard D. Bowden, Kate Lajtha, Susan E. Washko, Sarah J. Wurzbacher, Myrna J. Simpson
更新时间: 2019-01-01
摘要: Forest soil organic carbon (SOC) is one of the largest reservoirs of terrestrial carbon (C) and is a major component of the global C cycle. Yet there is still uncertainty regarding how ecosystems, and the SOC they store, will respond to changes due to anthropogenic processes. Current and future reactive nitrogen (N) deposition to forest soils may alter biogeochemical processes and shift both the quantity and quality of stored SOC. We studied SOC storage and molecular-level composition after 22 years of N additions (100 kg N ha−1 y−1) in a temperate deciduous forest. SOC storage in surface soils increased by 0.93 kg m−2 due to a decline in microbial biomass (phospholipid fatty acids) and litter decomposition. N additions resulted in the selective preservation of a range of plant-derived compounds including steroids, lignin-derived, cutin-derived, and suberin-derived compounds that have anti-microbial properties or are non-preferred microbial substrates. This overall shift in SOC composition suggests limited sustainability and a decline in soil health. The reduction in microbial biomass and increase in specific SOC components demonstrate that long-term N fertilization negatively alters fundamental C cycling in forest soils. This study also demonstrates unequivocally that anthropogenic impacts on C and N cycling in forests at the molecular-level must be considered more holistically.
24740. 题目: Organic fertilizer, but not heavy liming, enhances banana biomass, increases soil organic carbon and modifies soil microbiota
文章编号: N18123105
期刊: Applied Soil Ecology
作者: Jiangzhou Zhang, Shuikuan Bei, Baoshen Li, Junling Zhang, Peter Christie, Xiaolin Li
更新时间: 2018-12-31
摘要: Low soil pH and low soil organic matter content are major factors limiting banana production in acid soils. A pot experiment was conducted to determine whether liming or organic fertilizer is effective in mediating banana growth and soil health. The experiment comprised an unamended control and two treatments, lime and OF (organic fertilizer) and sampling was conducted twice, 65 and 280 days after planting. Soil nutrient concentrations, soil microbial communities and enzyme activities, and banana biomass and nutrient uptake were determined. As expected, the application of lime or organic fertilizer significantly increased soil pH and mineral nutrient concentrations and decreased Al3+ concentration. At both harvests an increase in bacterial and fungal diversity in the lime treatment and a shift in the soil bacterial and fungal communities did not translate into increased plant biomass. Organic fertilizer application significantly increased soil organic carbon content and enzyme activities, root length density down the soil profile, plant biomass and nutrient uptake compared to the lime treatment and the control. Changes in the soil microbial community in the organic fertilizer treatment compared to the control followed the same direction as in the lime treatment. However, the relative abundances of Actinobacteria and Ascomycota increased significantly 280 days after planting and potential pathogenic fungi including Fusarium decreased. Our results indicate that heavy liming alone may not be a viable approach to overcome the growth limiting factors in banana production on acid soils. In addition to the increased soil organic matter and nutrient availability, organic fertilizer may prime microbial activities and act as biologically active agent and/or enhance synergistic interactions within the soil microbiome in enhancing plant biomass. Increased soil biological activities after organic fertilizer application emphasize the importance of soil health in promoting the yield of banana crops.
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