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24261. 题目: Chemodiversity of Soil Dissolved Organic Matter
文章编号: N20042901
期刊: Environmental Science & Technology
作者: Yang Ding, Zhenqing Shi, Qianting Ye, Yuzhen Liang, Minqin Liu, Zhi Dang, Yujun Wang, Chongxuan Liu
更新时间: 2020-04-29
摘要: Dissolved organic matter (DOM) plays a key role in many biogeochemical processes, but the drivers controlling the diversity of chemical composition and properties of DOM molecules (chemodiversity) in soils are poorly understood. It has also been debated whether environmental conditions or intrinsic molecular properties control the accumulation and persistence of DOM due to the complexity of both molecular composition of DOM and interactions between DOM and surrounding environments. In this study, soil DOM samples were extracted from 33 soils collected from different regions of China, and we investigated the effects of climate and soil properties on the chemodiversity of DOM across different regions of China, employing a combination of Fourier transform ion cyclotron resonance mass spectrometry, optical spectroscopy, and statistical analyses. Our results indicated that, despite the heterogeneity of soil samples and complex influencing factors, aridity and clay can account for the majority of the variations of DOM chemical composition. The finding implied that DOM chemodiversity is an ecosystem property closely related to the environment, and can be used in developing large-scale soil biogeochemistry models for predicting C cycling in soils.

24262. 题目: Effect of quorum quenching on EPS and size-fractioned particles and organics in anaerobic membrane bioreactor for domestic wastewater treatment
文章编号: N20042804
期刊: Water Research
作者: Boyan Xu, Tze Chiang Albert Ng, Shujuan Huang, How Yong Ng
更新时间: 2020-04-28
摘要:

Quorum quenching (QQ) has been applied as a promising membrane fouling control strategy for anaerobic membrane bioreactors (AnMBRs). Nevertheless, long-term operation of AnMBRs for real domestic wastewater (DWW) treatment needs to be systematically studied to evaluate comprehensive membrane fouling mechanisms and bioprocess performance. In this study, the impact of QQ on membrane fouling was investigated using a quorum quenching AnMBR (QQAnMBR) deploying a bead-entrapped facultative quorum quenching consortium (FQQ) to treat DWW. FQQ was shown to prolong membrane filtration operation by an average of 75%. Reduced proteins (p < 0.005) and carbohydrates (p < 0.005) in the extracellular polymeric substances (EPS) of mixed liquor (ML) were key differentiators that led to lower cake layer (CL) formation. Additionally, reduced biopolymers production (p < 0.05) in EPS improved sludge dewaterability. The findings suggested that QQ could alter fluorescent microbial metabolites of both EPS and CL as unveiled by excitation-emission matrix spectra pattern. Furthermore, colloidal particles (i.e., particles with size larger than 0.45 μm in ML supernatants) production was retarded by QQ, thereafter, also contributed to the reduced CL formation. Pore blockage was slightly increased by QQ, which might be attributed to pore blockage by large (∼230 nm) and small organic compounds (∼51 nm) in soluble microbial products (SMP). However, QQ had no significant impact on organic concentration of SMP, and QQ was not associated with particle size distribution of biomass. QQ performance was further affirmed through suppressed production of C4-HSL, 3-OXO-C6-HSL, and C6-HSL. The overall AHLs degradability of FQQ was well-maintained even after five membrane service cycles (total operation of 70 d). Moreover, QQ had no compromised impact on treatment performance (i.e., chemical oxygen demand (COD) removal and methane yield). Collectively, this study bridged the knowledge gap to bring forward QQ technology in AnMBR for widespread domestic wastewater treatment application.

24263. 题目: Accumulation of organic carbon in a large canyon reservoir in Karstic area, Southwest China
文章编号: N20042803
期刊: Environmental Science and Pollution Research
作者: Yong Qin, Feng Hao, Dong Zhang, Yunchao Lang, Fushun Wang
更新时间: 2020-04-28
摘要: Artificial reservoirs play an important role in intercepting organic carbon (OC), which affects the carbon cycle of inland waters. However, limited by the methods of field observations, studies on the potential carbon sink of sediment in reservoirs are not accurate enough. In this study, we investigated OC accumulation in the Wujiangdu Reservoir (WJDR), a canyon reservoir located in a karst area of Southwest China, by coupling seismic survey data with physicochemical data of sediment cores. The results showed that irregular underwater topography resulted in spatial heterogeneity of the sediment deposition. The mean OC accumulation rate in the WJDR was 579.2 g C m⁻² year⁻¹, and the OC accumulation flux of the WJDR was 1.4 × 10¹⁰ g C year⁻¹. δ¹³C values coupled with a mixing model indicated that the autochthonous OC ranged from 14.2 to 97.0% of the total OC in the sediment, with an average of 48.4%. The significantly positive relationship between autochthonous OC and TN indicated that the autochthonous OC generated in the reservoir was associated with nutrient input. The autochthonous OC accumulation flux was 6.6 × 10⁹ g C year⁻¹, which was equal to 2.3 times the carbon emission from the reservoir surface to the atmosphere as CO₂-C, indicating that the autochthonous OC produced within the reservoir is a large carbon sink.

24264. 题目: Disentangling the role of extracellular polysaccharides in desiccation tolerance in lichen‐forming microalgae. First evidence of sulfated polysaccharides and ancient sulfotransferase genes
文章编号: N20042802
期刊: Environmental Microbiology
作者: María González‐Hourcade, Eva M. Campo, Marcia R. Braga, Antonio Salgado, Leonardo M. Casano
更新时间: 2020-04-28
摘要:

Trebouxia sp. TR9 and Coccomyxa simplex are desiccation‐tolerant microalgae with flexible cell walls, which undergo species‐specific remodelling during dehydration‐rehydration (D/R) due to their distinct ultrastructure and biochemical composition. Here, we tested the hypothesis that extracellular polysaccharides excreted by each microalga could be quantitatively and/or qualitatively modified by D/R. Extracellular polysaccharides were analysed by size exclusion and anion exchange chromatography, specific stains after gel electrophoresis and GC/MS of trimethylsilyl derivatives (to determine their monosaccharide composition). The structure of a TR9 sulfated polymer was deduced from NMR analyses. In addition, sugar‐sulfotransferase encoding genes were identified in both microalgae and their expression was measured by RT‐qPCR. D/R did not alter the polydispersed profile of extracellular polysaccharides in either microalga but did induce quantitative changes in several peaks. Furthermore, medium‐low‐sized uronic acid‐containing polysaccharides were almost completely substituted by higher molecular mass carbohydrates after D/R. Sulfated polysaccharide(s) were detected, for the first time, in the EPS of both microalgae, but only increased significantly in TR9 after cyclic D/R, which induced a sugar‐sulfotransferase gene and accumulated sulfated ß‐D‐galactofuranan(s). Biochemical remodelling of extracellular polysaccharides in aeroterrestrial desiccation‐tolerant microalgae is species‐specific and seems to play a role in the response to changes in environmental water availability.

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24265. 题目: Efficient removal of perfluorooctane sulphonate by nanofiltration: Insights into the effect and mechanism of coexisting inorganic ions and humic acid
文章编号: N20042801
期刊: Journal of Membrane Science
作者: Changwei Zhao, Tong Zhang, Guangshuo Hu, Jun Ma, Ruiping Song, Jiding Li
更新时间: 2020-04-28
摘要:

The removal of perfluorooctane sulphonate (PFOS) with coexisting substances is very important. Inorganic ions and humic acid (HA) commonly coexist and may influence PFOS removal performance. However, there is little information on the capacity for systematic PFOS removal in the presence of inorganic ions and HA during nanofiltration (NF) process. In this paper, the impact of the coexistence of anions, cations, and HA on PFOS removal were investigated by NF. More specifically, the effect and interaction of anions, cations, and HA on PFOS removal performance and mechanism were examined. The PFOS removal rejection increased from 92% to 99% when HA was present together with both cations and anions. The higher the valence of the inorganic ion was, the greater the PFOS rejection was. The sieving effect was dominant in the improvement of PFOS removal by the presence of cations. The electrostatic repulsion played an important role in the improvement of PFOS removal by the presence of anions. Furthermore, density functional theory (DFT) was applied to calculate the interaction between PFOS molecules, cations, and HA. Corresponding DFT structures and thermodynamics parameters were obtained. It showed that the Ca²⁺ ions could more easily bridge two PFOS than one PFOS, HA could more easily coordinate with both Ca²⁺ and PFOS molecules. The increase of PFOS size after the coordination reaction results in the improvement of the sieving effect. Additionally, other analyses including X-ray photoelectron spectroscopy, atomic force microscopy, and the surface zeta potential also demonstrated the sieving effect mainly governed PFOS removal in coexistence with HA and cations. The electrostatic repulsion was dominant in PFOS separation performance in coexistence with HA and anions.

24266. 题目: Bacterial and archaeal taxa are reliable indicators of soil restoration across distributed calcareous grasslands
文章编号: N20042703
期刊: European Journal of Soil Science
作者: Melanie Armbruster, Tim Goodall, Penny Hirsch, Nick Ostle, Jeremy Puissant, Kate Fagan, Richard Pywell, Rob Griffiths
更新时间: 2020-04-27
摘要:

Land use intensification can reduce soil carbon stocks and changes microbial community biodiversity and functionality. However, there is a lack of consensus on whether management consistently affects microbial biodiversity across geographic scales, and how this relates to altered soil function. From a regulatory and monitoring perspective, there is a need to identify functionally relevant indicators of land use in order to evaluate the progress of soil restoration approaches. We performed a landscape scale survey of unimproved calcareous grasslands paired with local arable contrasts, and assessed the consistency of responses in a variety of soil, biotic and functional measures. In addition, adjacent grasslands undergoing restoration were assessed to identify soil microbial indicators of recovery. Organic matter content was consistently larger in grasslands than in arable fields, and increased with time in the restoring sites. Molecular comparisons of grassland versus arable soils revealed numerous bacterial, archaeal and fungal indicators, with more representatives of Ca. Xiphinematobacter, DA101, Bradyrhizobium, Rhodoplanes, Mycobacteria and Mortierella in old grassland soils, while Nitrososphaera, Sporosarcina and Alternaria infectoria were more abundant in arable soils. Extracellular enzymatic responses were more variable with none of the eight investigated enzymes being consistent indicators of grassland or arable soils. Correlation analyses, incorporating the molecular and enzymatic responses across all surveyed soils, revealed that molecular indicators were more strongly correlated with soil organic matter increases with restoration of arable soils. Our results highlight that microbial taxa are among the most sensitive indicators of soil restoration, and we identify consistent responses of specific taxa to management across geographic scales. This discovery will be important for both the instigation and monitoring of the soil restoration.

This article is protected by copyright. All rights reserved.

24267. 题目: Fencing decreases microbial diversity but increases abundance in grassland soils on the Tibetan Plateau
文章编号: N20042702
期刊: Land Degradation and Development
作者: Dandan Fan, Weidong Kong, Fei Wang, Linyan Yue, Xiangzhen Li
更新时间: 2020-04-27
摘要:

Fencing usually increases soil organic carbon and nutrients and eventually enhances soil microbial diversity, however with different or even conflicting results, the mechanisms underlying the diversity reduction remain unclear. Aiming to reveal the mechanism of diversity reduction, we explored the soil microbial diversity and community structure in fencing (5‐years and 10‐years) and grazing during a growing season in arid and semi‐arid steppe, using Illumina sequencing of 16S and 18S rRNA genes. The results revealed that fencing and season both substantially increased soil total organic carbon (TOC), while the enhancing TOC substantially reduced soil pH. Fencing significantly increased bacterial and eukaryotic abundance due to the enhancing TOC, which was indicated by positive correlation (p < 0.05). Contrastingly, fencing significantly decreased bacterial and eukaryotic diversity. Our results further revealed that fencing‐ and season‐driven change in soil water content and soil pH played key roles in reducing the bacterial and eukaryotic diversity, respectively. Distance‐based linear model demonstrated that fencing dominantly drove the soil bacterial and eukaryotic community variations by explaining 15.64% and 24.88%, respectively, and redundancy analysis showed that the fencing effect was dependent on growing months. Bacteria were dominanted by Cyanobacteria and Proteobacteria, and eukaryotes were dominanted by Streptophyta, Ascomycota and Basidiomycota. Cyanobacteria relative abundance remained stable from May to September in fencing but substantially increased in grazing. Our findings offer a new insight into the mechanism of the soil microbial diversity reduction, and reveal the season‐dependency of fencing effect in arid and semi‐arid grasslands.

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24268. 题目: The influence of soil warming on organic carbon sequestration of arbuscular mycorrhizal fungi in a sub-arctic grassland
文章编号: N20042701
期刊: Soil Biology and Biochemistry
作者: Jing Zhang, Alf Ekblad, Bjarni D. Sigurdsson, Håkan Wallander
更新时间: 2020-04-27
摘要:

A substantial portion of grassland photosynthates is allocated belowground to arbuscular mycorrhizal fungi (AMF), but controversy remains about whether this carbon (C) contributes to soil organic carbon (SOC) under warming. The goal of this study was to investigate how AMF biomass and C sequestered by AMF (C_New) are influenced by soil warming. We estimated the AMF biomass and C_New, assumed to be mostly AMF necromass, in mycelial ingrowth bags buried for 1, 2, or 3 years in soil under warming (∼+0.5–16.4 °C). The AMF biomass had a positive, curvilinear response to warming gradients after one year of burial. About 107 g C m⁻² of C_New accumulated over the three years and ∼12% of this C was from glomalin-related soil protein. Modelling suggested the production rate of AMF biomass was 153 g C m⁻² yr⁻¹ with a rapid (36–75 days) turnover while AMF necromass turnover was much slower (1.4 ± 0.2 yr⁻¹). Warming duration (7–9 years vs. > 50 years) did not have significant influence on AMF biomass or C_New (P > 0.05). Our results suggest that AMF are more tolerant to increases in temperature than other microbes or fine roots. The dramatic loss of soil C and stable soil aggregates under warming found earlier at this site were not attributed to a decrease AMF biomass or C_New. Despite a low AMF standing biomass, its contribution to SOC may be substantial.

24269. 题目: The contribution of prokaryotes and terrestrial plants to Maldives inter-atoll sapropels: Evidence from organic biomarkers
文章编号: N20042611
期刊: Organic Geochemistry
作者: Masatoshi Nakakuni, Keiko Takehara, Peter K. Swart, Shuichi Yamamoto
更新时间: 2020-04-26
摘要:

The composition of organic matter in early Miocene sediment cores obtained from International Ocean Discovery Program Expedition 359 (IODP Exp. 359) was analysed using tetramethylammonium hydroxide (TMAH) thermochemolysis, a method used to determine concentrations of lignin phenols, fatty acids, sterols and hopanoids. These early Miocene sediment cores contain thick sequences (∼100 m) of interbedded light (organic-poor) and dark (organic-rich) sedimentary layers. A total of 49 samples from cores between 704.4 mbsf to 803.95 mbsf (∼20–23 Ma) at Site U1466 (518 m water depth) was selected with particular emphasis placed on the dark layers, although the light layers were also sampled. While organic compounds were below detection limits in the lighter coloured sedimentary layers, the dark layers, with concentrations of organic carbon up to 20%, contained varying concentrations of all analysed compounds. Although sterols were present, hopanoids were more abundant in the dark layers. The contribution of prokaryotic organisms, estimated from the ratio (hopanols and hopanoic acids/[sterols + hopanols and hopanoic acids]), indicates that it was prokaryotic organisms rather than eukaryotic organisms that contributed the majority (∼90%) of the organic matter in the dark layers. In conjunction with this record, more negative δ¹⁵N values in the darker layers suggest that the prokaryotic organisms were nitrogen-fixing microorganisms (presumably cyanobacteria). The long-to-short fatty acid ratios, together with sterol distributions and the concentration of lignin phenols, suggest the input of terrestrial plant material occurred during a high total organic carbon (TOC) interval (∼770–810 mbsf), which coincides with more negative carbon isotope ratios. Additionally, the long-to-short fatty acid ratio in this interval was significantly higher in the dark layers than the light layers, suggesting that terrestrial environments suitable for vegetation growth expanded during the interval represented by the dark layers. Furthermore, the ratio of cinnamyl lignin phenols to vanillyl lignin phenols (C/V) is relatively high during these intervals. From these biomarker tracers, we speculate that the terrestrial vegetation was dominated by herbaceous plants adapted to frequent sea-level changes.

24270. 题目: Phase changes of continuous cropping obstacles in strawberry (Fragaria × ananassa Duch.) production
文章编号: N20042610
期刊: Applied Soil Ecology
作者: Peng Chen, Yu-zhu Wang, Qi-zhi Liu, Yun-tao Zhang, Xing-yue Li, He-qin Li, Wei-hua Li
更新时间: 2020-04-26
摘要:

Soil ecology plays an important role in the growth and health of plants. Research suggests that long-term monocropping may lead to soil ecological disorders. In this study, we aimed to understand the reasons for the decrease in plant productivity stemming from long-term monoculture cropping. Greenhouse studies were conducted to determine the cause of continuous cropping (CC) obstacles in soils under 12 years of continuous strawberry (Fragaria × ananassa Duch.) production. The data suggested that CC led to three phases of changes in abiotic and biotic soil factors. In phase I (CC for 2–6 years), significant changes were observed only in soil physicochemical properties, such as the pH, total nitrogen (TN), ammonium nitrogen (NH₄⁺-N), available phosphorus (AP), available potassium (AK) and soil organic matter (SOM), which obviously changed from the second year to the sixth year. In phase II (CC for 6–8 years), two biotic factors, key fungi such as Fusarium, Humicola and Arthrobotrys and soil nematodes, i.e., populations and communities of nematodes, started to change significantly in terms of their abundance. In phase III (CC for >8 years), the accumulation of phenolic acids, i.e., p-hydroxybenzoic acid (p-HBA), ferulic acid (FA), p-coumaric acid (p-CA) and cinnamic acid (CA), significantly inhibited crop growth, and the abundance of key bacteria, including Bacillus, Sphingomonas and Sphingopyxis, started to change significantly from the eighth CC year. The results in this study provide useful information for solving CC obstacles in strawberry production.

24271. 题目: Comparing the effects of soil fauna on litter decomposition and organic matter turnover in sustainably and conventionally managed olive orchards
文章编号: N20042609
期刊: Geoderma
作者: Adriano Sofo, Alba Nicoletta Mininni, Patrizia Ricciuti
更新时间: 2020-04-26
摘要:

Soils and crops in Mediterranean agrosystems are vulnerable to climate change and environmental stresses, and they will be more and more in the next future. In this scenario, soil organic matter (SOM) plays a crucial role and its level is principally determined by the continuous physical and chemical action of soil fauna. While the importance of microorganisms in fruit agrosystems has been extensively and recently highlighted, the role of soil fauna - and particularly of macrofauna - to ecosystem services has been often overlooked. On this basis, the aim of this study was to characterize and compare C/N dynamics and other soil physicochemical parameters, soil macrofauna abundance, bioturbation and litter/SOM decomposition indices in a Mediterranean olive (Olea europaea L.) orchard subjected to two different soil management systems (namely sustainable, S_mng, and conventional, C_mng) for 18 years. The adoption of the S_mng system significantly increased almost three times the abundance of earthworms and two times that of other soil macrofauna. Bioturbation due to soil fauna and roots was significantly higher in the S_mng system, and this caused a significantly faster SOM decomposition measured both in 90-day incubated local litter bags (decomposition constant = 0.092 and 0.072 in the S_mng and C_mng system, respectively) and in tea bags (decomposition rate constant = 0.018 and 0.010 in the S_mng and C_mng system, respectively). Soil C and N dynamics were also affected by different soil management. The results highlighted that the soil chemical quality of the S_mng system is the result of the higher abundance and activity of soil fauna, in terms of enhanced litter decomposition and bioturbation. From the general analysis of the data obtained, it emerged that the role of soil fauna should be seriously taken into account in land management strategies not exclusively oriented to fruit yield and quality, but also to soil fertility restoration.

24272. 题目: Adsorption of dissolved organic matter (DOM) on polystyrene microplastics in aquatic environments: Kinetic, isotherm and site energy distribution analysis
文章编号: N20042608
期刊: Ecotoxicology and Environmental Safety
作者: Abliz Abdurahman, Kunyan Cui, Jie Wu, Shuocong Li, Rui Gao, Juan Dai, Weiqian Liang, Feng Zeng
更新时间: 2020-04-26
摘要:

Microplastics and dissolved organic matter (DOM) are ubiquitous in aquatic environments. The adsorption behavior of DOM on microplastics in aquatic environments is a prominent concern. In this study, the adsorption of two types of DOM, Suwannee River Humic Acid (HA) and Suwannee River Fulvic Acid (FA), on polystyrene microplastics (PSMPs, 10 μm) in aquatic environments was investigated. The adsorption of both HA and FA on PSMPs could be well described by using pseudo second-order and Freundlich models. The adsorption of HA and FA on PSMPs was low pH-dependent, particularly for FA adsorption. However, the elevated ionic strength slightly increased the adsorption of HA and FA on PSMPs. Based on Freundlich model, the site energy distribution of HA and FA adsorption on PSMPs under the experimental conditions were estimated. HA and FA first occupied the high-energy adsorption sites and then diffused to the low-energy adsorption sites on PSMPs. With higher site energies, HA demonstrated a much stronger adsorption affinity to PSMPs than FA. The adsorption site heterogeneity (σ_e*) on PSMPs under the experimental conditions were close. Hydrophobic interaction and π-π electron donor acceptor interaction acted simultaneously in the HA and FA adsorption on PSMPs. The results of this study suggested that the environmental behaviors of microplastics would be influenced by the amount and the type of DOM as well as solution chemistry.

24273. 题目: Copper and Zn distribution in humic substances of soil after 10 years of pig manure application in south of Santa Catarina, Brazil
文章编号: N20042607
期刊: Environmental Geochemistry and Health
作者: Lucas Benedet, Deborah Pinheiro Dick, Gustavo Brunetto, Elano dos Santos Júnior, Guilherme Wilbert Ferreira, Cledimar Rogério Lourenzi, Jucinei José Comin
更新时间: 2020-04-26
摘要: This study aims to evaluate available Cu and Zn levels in soil and related in soil organic matter (SOM) fractions (fulvic acids—FA, humic acids—HA, and humins—HU) after 10 years of application of pig slurry (PS) and pig deep litter (PL). Soil samples were collected from an experiment with black oat/corn succession under no-tillage in southern Brazil. The treatments consisted of fertilization of 90 and 180 kg N ha⁻¹ applied as PS and PL from 2002 to 2012 and a control treatment without any fertilization. SOM chemical fractionation was performed in air-dried samples. Copper and Zn concentrations were analyzed in soil (total, EDTA- and CaCl₂-extracted) and in SOM fractions. The amount of Cu and Zn (in mol) related to each fraction of SOM (Cu/C and Zn/C molar ratios) was established. The applications of PS and PL promoted the accumulation of total and available Cu and Zn, especially in the PL180 treatment. The highest amount of Zn was found with HU, while for Cu both HA and HU were important retention compartments. The highest Cu/C_FA, Cu/C_HA and Cu/C_HU ratios were found with the addition of PL. Increases in Zn/C ratio were found mainly in FA fraction. The high levels of Cu and Zn obtained in the HCl-extracted SOM fraction suggest that a considerable part is bound to SOM and clay minerals with low energy. However, the SOM is an important source of metal adsorption in soils with swine manure application.

24274. 题目: Synthesis of vinasse-dolomite nanocomposite biochar via a novel developed functionalization method to recover phosphate as a potential fertilizer substitute
文章编号: N20042606
期刊: Frontiers of Environmental Science & Engineering
作者: Nima Kamali, Abdullah Rashidi Mehrabadi, Maryam Mirabi, Mohammad Ali Zahed
更新时间: 2020-04-26
摘要: The effectiveness of phosphate (P) removal from aqueous solutions was investigated by novel low-cost biochars synthesized from vinasse and functionalized with calcined dolomite. The vinasse-derived biochar, synthesized via pyrolysis at different temperatures, showed easy preparation and a large surface area. The novel vinasse biochar nanocomposites were prepared by adding dolomite to the vinasse biochars with different weight percentages (10, 20 and 30%). The characteristics of the prepared materials were identified for further understanding of the inherent adsorption mechanism between P ions and vinasse biochars. Vinasse-dolomite nanocomposite was very effective in the adsorption of P species from aqueous media. The effect of the operational factors on Vinasse-dolomite nanocomposite was explored by applying response surface methodology (RSM). According to RSM results, the optimum condition was achieved to be contact time 90 (min), 250 (mg/L) of P concentration and pH 7. Thermodynamic isotherm and kinetic studies were applied on experimental data to understand the adsorption behavior. The Vinasse-dolomite nanocomposite revealed preferential P species adsorption in the presence of co-existing anions. The P species could be recovered by 1.0 M HCl where the efficiency was not affected up to the fifth cycle. The P-loaded Vinasse-dolomite nanocomposite was successfully tested on a plant; it significantly improved its growth and proved its potency as a P-based fertilizer substitute.

24275. 题目: Responses of organic and inorganic phosphorus fractions in brown earth to successive maize stover and biochar application: a 5-year field experiment in Northeast China
文章编号: N20042605
期刊: Journal of Soils and Sediments
作者: Dianyun Cao, Yu Lan, Zunqi Liu, Xu Yang, Sainan Liu, Tianyi He, Di Wang, Jun Meng, Wenfu Chen
更新时间: 2020-04-26
摘要: Purpose To compare the effects of maize stover and its biochar on soil P fractions and investigate the effects of different stover incorporation practices (direct return or pyrolysis) on the transformation of soil P fractions after a long-term field experiment. Materials and methods Total P, Olsen-P, inorganic P fractions, and organic P fractions were analyzed via a 5-year field experiment growing maize. The treatments were as follows: CK0 (no fertilizer application or amendment), CK (application of mineral NPK fertilizer), ST (application of maize stover at 7.5 t ha−1 along with mineral NPK fertilizer), and BC (application of biochar at 2.63 t ha−1, a rate approximately equivalent to a maize stover biomass of 7.5 t ha−1; the biochar was charred according to a 35% output ratio in the factory). All treatments received N mineral fertilizer at 120 kg N ha−1, P mineral fertilizer at 26 kg P ha−1, and K mineral fertilizer at 50 kg K ha−1 annually. Results and discussion Relative to the initial fractions in 2013, biochar generally increased the inorganic P fractions (Ca8-P, Ca10-P, Al-P, and Fe-P), and maize stover generally increased the organic P fractions (MLOP, MROP, and HROP), while both maize stover and its biochar significantly decreased O-P in the soil. After 5 years (in 2017), relative to CK treatment, amendment with maize stover and its biochar increased total P and decreased Olsen-P. The total inorganic P, Ca8-P, and Fe-P were significantly increased by biochar. Ca2-P and O-P were significantly decreased by maize stover and its biochar. Total organic P was increased with maize stover and biochar amendment. LOP and HROP were significantly increased under biochar application, and all organic P fractions were significantly increased under maize stover amendment. Conclusions The application of maize stover and its biochar affected both organic and inorganic phosphorus fractions; biochar had a more advantageous effect on the soil inorganic P fractions, while stover had a greater effect on the content of organic P fractions.

24276. 题目: Carbon and nutrient accumulation in mangrove sediments affected by multiple environmental changes
文章编号: N20042604
期刊: Journal of Soils and Sediments
作者: Alexander Pérez, Wilson Machado, Dimitri Gutierrez, Joseph M. Smoak, Joshua L. Breithaupt, Maritza S. Saldarriaga, Luciana Sanders, Humberto Marotta, Christian J. Sanders
更新时间: 2020-04-26
摘要: Purpose In order to assess the impact of anthropogenic activities on carbon and nutrient accumulation, total organic carbon (TOC), nitrogen (TN), and phosphorus (TP) accumulation rates were examined in a 210Pb-dated mangrove sediment core from Sepetiba Bay, Brazil, a coastal region impacted by multiple environmental changes during the previous century. Materials and methods A 50-cm length sediment core was collected from a mangrove forest in Sepetiba Bay. Sediment subsamples were analyzed to measure TOC, TN, δ13C, and δ15N using an elemental analyzer attached to an isotope ratio mass spectrometer Thermo Finnigan Model Delta Plus XP, whereas colorimetric analysis were used to measure TP. For 210Pbex analyses, gamma-ray measurements were performed in a semiplanar intrinsic germanium high purity coaxial detector, coupled to a multichannel analyzer, whereas the sediment accumulation rate (SAR) was calculated according to the constant initial concentration (CIC) method. Also, carbon and nutrient fluxes were calculated using SAR and TOC, TN, and TP contents, whereas statistical differences were evaluated by ANOVA + Tukey HSD analysis with previous data normalization. Results and discussion The calculated sedimentation rate (~ 8.1 mm year−1) since the early 1900s was up to threefold higher than the global mean determined for mangrove forests (~ 2.8 mm year−1) and the regional sea level rise (~ 3.2 mm year−1). Significantly higher TOC, TN, and TP fluxes, up to nearly 1000, 90, and 15 g m−2 year−1, respectively, were observed after the water diversion from a nearby drainage basin in the 1950s and an increase in sewage effluent input, which increased in the early 1990s. After this period, lighter δ13C values (~ − 25‰) indicate an increased importance of the terrestrial organic matter source, while lower TOC:TN ratios (~ 11) and heavier δ15N values (~ + 9‰) suggest an increased influence of anthropogenic fertilization on inorganic nitrogen accumulation. Conclusions The significantly higher accumulation rates during the last decades evidenced the role of mangrove sediments as sinks for anthropogenically enhanced inputs of carbon and nutrients. Also, studies on carbon and nutrient accumulation evidenced the need for further research in eutrophic coastal areas.

24277. 题目: Soil conservation practices contribution in trapping sediment and soil organic carbon, Minizr watershed, northwest highlands of Ethiopia
文章编号: N20042603
期刊: Journal of Soils and Sediments
作者: Mulatie Mekonnen, Mekonnen Getahun
更新时间: 2020-04-26
摘要: Purpose Globally, land degradation and climate change are priority problems. Therefore, this study was conducted in Minizr catchment in the northwest highlands of Ethiopia to investigate the sediment and sediment organic carbon (SOC) trapping role of soil and water conservation practices (SWCPs) constructed inside fields, check dams (CDs) constructed inside gullies and micro-trenches constructed on degraded grazing lands, which would help to reduce land degradation and climate change. Our three research questions were: How much sediment was trapped by SWCPs How much SOC was trapped by SWCPs What was the role of SWCPs in mitigating climate change Materials and methods Google Earth Imagery was used to map the SWCPs constructed inside fields; a Digital Elevation Model (ASTER DEM 20 m) was used to delineate the boundary of the study watershed and to evaluate elevation and slope characteristics, and GPS was used to collect watershed outlet coordinate points, CD locations and to accurately digitize SWCPs. Three different SWCPs, five different CDs and 30 micro-trenches were evaluated for their sediment and SOC trapping efficiency. The experiment was designed in three treatments with three replications, except for the CD studies. The volume of sediment trapped was quantified using field measurements of the deposited sediment and SOC was determined in a soil laboratory. Results and discussion The investigated SWCPs, CDs and micro-trenches trapped ~584,745 kg SOC together with 32,105 t of sediment. The percentage SOC was higher in the CD sediments (1.98%) than SWCPs (1.38%) and micro-trenches (1.49%). A large amount of SOC was deposited in vegetative-supported CDs than CDs constructed from structures alone, i.e. CDs supported with vegetative practices trapped more SOC. Conclusions In general, SWCPs, CDs and micro-trenches were found to reduce soil erosion or land degradation by enhancing sediment deposition. They also trapped large amounts of SOC together with the sediment, which can reduce the greenhouse gases emission to the atmosphere. Therefore, governmental and non-governmental organizations and professionals should also consider SWCPs as climate change mitigation measures, like that of afforestation/plantation.

24278. 题目: Low-molecular-weight organic acids as important factors impacting seawater acidification: A case study in the Jiaozhou Bay, China
文章编号: N20042602
期刊: Science of the Total Environment
作者: Haorui Liang, Li-Na Lyu, Chengjun Sun, Haibing Ding, Eyal Wurgaft, Gui-Peng Yang
更新时间: 2020-04-26
摘要:

Low-molecular-weight organic acids (LMWOAs) are ubiquitous water-soluble organic compounds with mass production worldwide, but their influence on coastal marine environments is still lack of consideration. In this study, we select a typical nearshore bay - the Jiaozhou Bay, which is surrounded by Qingdao — a city with modern manufacture, agriculture, aquaculture and service industry, as study area, to investigate the effect of LMWOAs on the nearshore marine environment, and their impact on seawater acidification in coastal areas. During Sep. 2016 to Aug. 2017, we identified three different LMWOAs – acetic acid (AA), formic acid (FA) and lactic acid (LA), with average concentrations of 46.7, 13.9 and 1.4 μmol·L⁻¹ in the seawater of the bay, respectively. Due to the establishment of the Jiaozhou Bay Bridge, the seawater exchange capacity was weakened and thereby the concentration and stocks of AA and FA increased. As weak acids in seawater, the influence of LMWOAs on the seawater acidification of the Jiaozhou Bay was investigated. LMWOAs had significant impact on seawater pH and every 10 μmol·L⁻¹ LMWOA caused an average of 0.02 pH unit decrease. From 2010 to 2017, pH value in the seawater of the bay decreased by about 0.103 and LMWOAs contributed about 83% of its decrease. Besides, two models were established to estimate the influence of LMWOAs on the seawater pH by applying the data set of dissolved inorganic carbon (DIC), total alkalinity (TA) and LMWOAs. The results showed that LMWOAs could enhance acidification of coastal seawater. Considering the importance of LMWOAs in seawater, it is necessary to evaluate their future changes in coastal marine environments. This study initiated a way to identify the source of LMWOAs in seawater and to evaluate their contribution to seawater acidification, and also provided a series of (Sutton et al., 2014) for future study on LMWOAs in coastal environment.

24279. 题目: An overview of organic matters in municipal wastewater: Removal via self-assembly flocculating mechanism and the molecular level characterization
文章编号: N20042601
期刊: Journal of Environmental Management
作者: R.T.V. Vimala, J. Lija Escaline, Kadarkarai Murugan, S. Sivaramakrishnan
更新时间: 2020-04-26
摘要:

On considering the critical issues in attaining stringent water quality standards and not creating any environmental impacts, we focused for the first time the economically feasible, emerging technology known as Self-assembly flocculating (Saf process). In which, the study investigated the applicability of bioflocculant (a biopolymer-self-assembly in nature) act as a surrogates on relying the removal of broad spectrum of substances under optimized conditions (Dosage: 90 mg/L; pH: 7; CaCl₂). On using different techniques, the results have proved in removing the organic matter such as pharmaceuticals (Gentamycin, Cholecalciferol, Fluvoxamine, 3-OH Desogestrel, and Pheniramine), endocrine disturbing compounds [Phthalic acid, Benzene, 1, 2, 4 -Trimethoxy-5-(1-Propenyl)-, Benzene, 1, 2-Dimethoxy-4-(2-Propenyl)-, 1, 2-Benzenedicarboxylic Acid, 3-Cyclohexen-1-ol], fluorescent components (Polysaccharide like material), and others. The toxicological assessment of self-assembly bioflocculant implemented on zebra fish were statistically correlated [r = 0.95, p < 0.01 and 0.05 for P₁WW; r = 0.91, p < 0.01 and 0.05 for P₂WW] and [r = 0.7 5, p < 0.05 for P₁WT; r = 0.095, p < 0.01 and 0.05 for P₂WT]. This integrated approach supplemented further information of zeta potential (−16 mV in P₁WW and −14.6 mV in P₂WW decreased to −1.05 mV and −1.56 mV) with particle size distribution to explain via Saf process. In this research, the new insight has established non-toxic, self-assembly, biodegradable, bioflocculant for effective bioremediation.

24280. 题目: Cluster analysis for time series based on organic geochemical proxies
文章编号: N20042515
期刊: Organic Geochemistry
作者: Ana Lúcia L. Dauner, Gesine Mollenhauer, Márcia C. Bícego, César C. Martins
更新时间: 2020-04-25
摘要:

Depositional and paleoenvironmental studies using organic geochemical proxies often present the temporal evolution of several compounds. Despite the importance of using several proxies to understand how the surrounding environment changed through time, this large amount of data usually hampers interpretations. In this scenario, the use of statistical tools for time series analysis can help simplify and interpret large data sets, even if they were not initially developed for molecular marker data. In this study, we show the benefits of using two different cluster analyses in order to: (i) group compounds with similar sources; and (ii) identify temporal zones. Cluster analysis using SAX (Symbolic Aggregate approXimation) represents groups of different proxies with similar sources (whether anthropogenic or natural, autochthonous or allochthonous), based on their temporal evolution. Temporal zones, on the other hand, can be identified by using a constrained cluster analysis, in which samples (sediment layers) are grouped according to the temporal variability of the organic compounds. These two approaches were successfully applied to organic proxy datasets from two sediment cores, retrieved from distinct environments and with distinct temporal recoveries. Based on these analyses, we were able to identify the probable source of compounds with multiple sources, and to show how the terrestrial and marine organic matter presented distinct patterns over time. These techniques do not replace the study of the temporal evolution of compounds individually but synthesize a large amount of information and may indicate which compounds of an assemblage yield the most robust information in environmental studies.