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25781. 题目: Potentially hazardous element accumulation in rice tissues and their availability in soil systems after biochar amendments
文章编号: N19030812
期刊: Journal of Soils and Sediments
作者: Feng Jing, Zhijiang Yang, Xiaomin Chen, Wei Liu, Bilin Guo, Gaozhe Lin, Ronghui Huang, Wenxin Liu
更新时间: 2019-03-08
摘要: Purpose: Biochar has shown to be a great product to control the bioavailability of potentially hazardous elements (PHE) in contaminated soils. Despite the advantages associated with the application of biochar in agricultural soils, relatively few studies have focused on the effects of biochar amendments on soil chemical properties, accumulation of arsenic, cadmium, zinc, and lead in rice tissues, and their availability in soil systems. Materials and methods: The field experiment was conducted at the paddy soils in Hunan Province, China. The soil texture was sandy clay loam. Wheat-derived biochar was applied once to the experimental plots at the rates of 0, 10, 20, 30 and 40 t ha⁻¹, and referenced as A0, A10, A20, A30, and A40, respectively. For PHE determination, soil samples and plant samples were digested with a mixed solution of HCl:HNO₃ (4:1, V:V) and HCl:HClO₄ (4:1, V:V), respectively, and the arsenic, cadmium, zinc, and lead in the digest solution were measured by ICP-MS (Thermo Fisher Scientific, USA). The soil available fraction of PHE (arsenic, cadmium, zinc, and lead) was extracted by diethylenetriamine pentaacetic acid (DTPA) and measured by inductively ICP-MS. Results and discussion: Biochar amendment increased chemical properties of soil organic matter, pH, electrical conductivity, cation exchange capacity, nitrate nitrogen, and available phosphorus. Soil DTPA extractable arsenic, cadmium, zinc, and lead concentrations were significantly reduced. Arsenic, cadmium, zinc, and lead in rice shoots, and arsenic, cadmium, and zinc in roots significantly decreased after amendment. Concentrations in rice tissues positively and negatively correlated with the soil available fraction of PHE and soil chemical properties, respectively. Soil electrical conductivity negatively correlated with the soil available fraction of PHE. Concentrations of arsenic, zinc, cadmium, and lead in rice roots declined relative to increases of cation exchange capacity (arsenic, zinc), available phosphorus (cadmium), and nitric nitrogen (lead) content. Similar relationships were observed between cation exchange capacity and PHE in shoots. Conclusions: Biochar creates avoidance of PHE through regulating chemical properties through biochar sorption capacity. Cation exchange capacity, available phosphorus, and nitric nitrogen were the principle factors affecting roots uptake of arsenic, zinc, cadmium, and lead. Biochar soluble salts could decline availability of metals/metalloids in soils through precipitation. Wheat-derived biochar application is an alternative safe product to immobilize PHE in rice paddy soils by restricting the risk of PHE.

25782. 题目: Effects of phytolithic rice-straw biochar, soil buffering capacity and pH on silicon bioavailability
文章编号: N19030811
期刊: Plant and Soil
作者: Zimin Li, Dácil Unzué-Belmonte, Jean-Thomas Cornelis, Charles Vander Linden, Eric Struyf, Frederik Ronsse, Bruno Delvaux
更新时间: 2019-03-08
摘要: Aims: Supplying phytolith-rich biochar in agrosystems increases soil pH, CEC and nutrient availability, adding to the impact of Si uptake on plant growth. Here we studied this specific impact as influenced by soil properties, and assessed the role of phytoliths to provide plant available Si. Methods: We used a young Cambisol and a highly weathered, poorly buffered, desilicated Nitisol. The biochars were produced from rice plants respectively enriched (Si+) and depleted (Si-) in Si. They had identical pH and nutrient contents, but largely differed in Si content (51.3 g Si kg⁻¹ in Si + vs 0.3 g Si kg⁻¹ in Si-). We compared their effects to that of wollastonite (CaSiO₃) on the biomass and mineralomass of wheat plants in a soil:solution:plant device. The contents of soil bioavailable Si and biogenic Si were assessed through an original CaCl₂ kinetic extraction and the DeMaster Na₂CO₃ alkaline dissolution, respectively. Results: The DeMaster technique dissolved Si from phytolith as well as from wollastonite. The soil buffering capacity (cmol_c kg⁻¹) was 31 in the Cambisol and 0.2 in the Nitisol. An identical supply of phytolithic biochar increased pH from 4.5 to 4.8 in the Cambisol, and from 4.8 to 7.4 in NI. It further increased the content of bioavailable Si (from 55 to 97 mg kg⁻¹ in the Cambisol, and 36 to 209 mg kg⁻¹ in the Nitisol), as well as plant Si uptake, biomass and Si mineralomass. That increase was largest in the Nitisol. Conclusions: The DeMaster technique did not specifically quantify the phytolith pool. This pool was the main source of plant available Si in both the Cambisol and Nitisol amended with phytolithic biochar. At identical phytolithic Si supply, however, soil pH and soil buffering capacity controlled the transfer of Si in the soil-plant system, which was largest in the poorly buffered Nitisol. The effect of phytolithic biochar on Si bioavailability was depending on soil constituents and properties, and thus on soil type.

25783. 题目: Facile Synthesis of Porous Carbons from Silica-rich Rice Husk Char for Volatile Organic Compounds (VOCs) Sorption
文章编号: N19030810
期刊: Bioresource Technology
作者: Yafei Shen, Niyu Zhang
更新时间: 2019-03-08
摘要: This work reported a facile synthesis of porous carbons from the silica-rich rice husk biochar via a ball-milling-assisted KOH activation for sorption of tar compounds and volatile organic compounds (VOCs) (i.e., toluene, phenol). The textural properties of activated biochars can be greatly influenced by the mass ratio of KOH and biochar. The high-performance biochar with a large specific surface area (S_BET: 1818 m²/g) was produced as the mass ratio was 3. This activated biochar exhibited a hierarchically meso-microporous structure, which benefited for the adsorption process. Particularly, it had long breakthrough time of 2784 min and high adsorption capacity of 264 mg/g for toluene, while it had short breakthrough time of 724 min and low adsorption capacity of 6.53 mg/g for phenol. Significantly, the mixed VOCs of toluene and phenol can be effectively adsorbed. Further, thermal desorption will be an alternative route for regeneration of waste activated biochar.
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25784. 题目: Effect of the isoelectric point of pH-responsive lignin-based amphoteric surfactant on the enzymatic hydrolysis of lignocellulose
文章编号: N19030809
期刊: Bioresource Technology
作者: Xuejuan Zhan, Cheng Cai, Yuxia Pang, Feiyang Qin, Hongming Lou, Jinhao Huang, Xueqing Qiu
更新时间: 2019-03-08
摘要: The isoelectric point (pI) of lignin-based surfactant is an important factor in the enhancement on the enzymatic hydrolysis of lignocellulose. In this work, lignin carboxylate (LC) and quaternary ammonium lignin carboxylates (LCQ-x, x%: the mass ratio of quaternizing agent to enzymatic hydrolysis lignin) with different isoelectric points were synthesized. LC or LCQ-x with pI significantly lower or higher than 4.8 reduced the non-productive adsorption of cellulase on lignin, but for the significant inhibitory effect on cellulase activity, their enhancements on the enzymatic hydrolysis of lignocellulose were not remarkable. However, LCQ-x with pI around 4.8 preserved the cellulase activity, and significantly reduced the non-productive adsorption of cellulase, therefore remarkably enhanced the enzymatic hydrolysis. 2 g/L LC, LCQ-40 (pI=5.0) and LCQ-100 (pI=9.2) increased the enzymatic digestibility of pretreated eucalyptus from 35.2% to 53.4%, 95.3% and 60.4% respectively. In addition, for the excellent pH-response performance, LCQ could be efficiently recovered after enzymatic saccharification.
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25785. 题目: The effect of vegetation change in C and N contents in litter and soil organic fractions of a Northern Iran temperate forest
文章编号: N19030808
期刊: CATENA
作者: Yahya Kooch, Razie Sanji, Masoud Tabari
更新时间: 2019-03-08
摘要: The properties of litter and soil, which are probably influenced by vegetation traits, have an effect on the fractions of C and N and ultimately global warming. In this study, litter and soil samples were collected from representative forestlands, including a mixed natural forest dominated by hornbeam‑ironwood and tree plantations of ash, maple, cypress and pine which are situated in a temperate area of Northern Iran. Main litter characteristics, soil aggregation and fractions of C and N were studied. Pine had the highest values of litter thickness (14.46 cm), C (60.31%) and C/N ratio (81.77 and 20.28 for litter and soil, respectively). However, litter N (2.20%), micro aggregates of total soil (39.75%), aggregate stability (73.86%) and macro aggregates of total soil (54.87%) were found significantly higher under the natural stands. Total C (2.58%), C in macro and micro aggregates (0.31 and 0.33 respectively), POM-C (4. 68 g/kg), DOC (125.54 mg/kg) and C sequestration (45.34 Mg/ha) were considerably higher under pine (for POM-C, pine ≈ cypress) and the greater values of total N (0.34%), N in macro and micro aggregates (0.10 and 0.08 respectively), POM-N (0.47 g/kg), DON (33.80 mg/kg) and N sequestration (6.86 Mg/ha) were observed under natural stands. Under our conditions, conversion of natural forest is due to reduction of soil N fractions and C increased under pine tree plantations.

25786. 题目: Responses of soil organic carbon and nutrient stocks to human-induced grassland degradation in a Tibetan alpine meadow
文章编号: N19030807
期刊: CATENA
作者: Zi-Qiang Yuan, Xiao-Jin Jiang, Guo-Jun Liu, Hui-Jun Jin, Ji Chen, Qing-Bai Wu
更新时间: 2019-03-08
摘要: Alpine meadow degradation is a major environmental problem in the Qinghai-Tibetan Plateau of China. While it is expanding at a rapid pace, quantitative information on the effect of grassland degradation on soil properties remains largely unavailable. This study aimed to evaluate the effect of vegetation cover reduction on soil organic carbon (SOC) and nutrient stocks. A degraded alpine meadow with vegetation cover gradients of 90% ± 6.6% to 70% ± 8.3% and 45% ± 8.7% was selected, and soil samples were collected at two soil depths (0–20 and 20–40 cm depths). The reduction in vegetation cover decreased soil sand, SOC, total nitrogen (N), available phosphorus (P), inorganic N, microbial biomass carbon and N, soil moisture, and the ratio of SOC to available P, but increased soil pH, bulk density, the ratio of SOC to total N, and clay and silt contents. The decline in vegetation cover from 90% to 45% significantly affected SOC, total N, total P, and available P stocks at 0–40 cm soil depths (p < 0.05, respectively), with losses as high as 3.89 kg m⁻² for SOC, 0.47 kg m⁻² for total N, and 1.05 g m⁻² for available P. These values corresponded to depletion rates at 28.7%, 39%, and 21%. The increases were as high as 39 g m⁻² for total P and corresponded to an increase rate of 15%. The structural stability index had a linear decrease trend with decreasing vegetation cover. The index was >9% at the COV90 site and was close to 5% at the COV45 site for 0–20 cm soil depth. These results confirmed that vegetation cover reduction is a key factor that influences the soil nutrient stocks and structural stability of the alpine meadow. The losses in SOC and nutrients by vegetation cover reduction on the alpine meadow can have a remarkable influence on a large scale. Meanwhile, the alpine meadow may have huge carbon and N sequestration potentials duo to the potential increase of vegetation productivity in this area.

25787. 题目: Biochars reduced the bioaccessibility and (bio)uptake of organochlorine pesticides and changed the microbial community dynamics in agricultural soils
文章编号: N19030806
期刊: Chemosphere
作者: Neelum Ali, Sardar Khan, Huaiying Yao, Juan Wang
更新时间: 2019-03-08
摘要: Biochar is considered as a universal sorbent used for soil amendment but its impacts on organochlorine pesticides (OCPs) and microbial communities associated with soil and vegetables are unclear. The effects of different biochars (derived from sewage sludge biochar (SSBC), soybean straw biochar (SBBC), rice straw biochar (RSBC) and peanut shells biochar (PNBC)), on bioaccessible fractions of OCPs in a contaminated soil and their subsequent bioaccumulation into vegetables (Chinese cabbage and spring onion) were investigated in this research work. The influence of these amendments on vegetable yields and soil microbial community using Illumina next generation sequencing technology was also assessed. The application of selected biochars significantly (p < 0.01) reduced the bioaccessibility of ∑OCPs in contaminated soil: SSBC (52%), PNBC (51%), RSBC (60%), and SBBC (47%), as compared to the control. The results indicated that following biochar additions, the bio-uptake of ∑OCP bio-uptake was considerably (from 86 to 85%) reduced in grown vegetables. Risk assessment showed that biochar amendments markedly (p < 0.01) decreased the hazard quotient (HQ) indices and incremental lifetime cancer risk (ILTR) values for OCPs associated with the consumption of vegetables. In addition, the results of high-throughput sequencing showed significant differences in microbial community structure between the treatments, which was driven by differences in the relative abundances of soil microbes. The relative abundances of Acidobacteria, Chloroflexi, Nitrospirae and Verrucomicrobia decreased following biochar additions. However, biochar amendments increased the relative abundances of Actinobacteria, Proteobacteria, Planctomycetes, Bacteroidetes, Firmicutes, and Gemmatimonadetes, though the increase in relative abundances of these phyla was strongly dependent on the type of biochar used.
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25788. 题目: Toxicity of exogenous hexavalent chromium to soil-dwelling springtail Folsomia candida in relation to soil properties and aging time
文章编号: N19030805
期刊: Chemosphere
作者: Xianglong Lin, Zaijin Sun, Long Zhao, Jin Ma, Xing Li, Fei He, Hong Hou
更新时间: 2019-03-08
摘要: Chromium (Cr) is a well-known toxic metal, but studies on Cr toxicity to soil-dwelling springtails are fairly limited, and did not consider the effects of various soil properties and long aging time. To address this, the chronic toxicity of Cr(VI) to survival and reproduction of model organism—Folsomia candida were evaluated in the laboratory studies. The results showed that compared to the soils aged only for 2 and 21 d, the concentrations inhibiting 50% reproduction (EC₅₀) significantly increased by 2.8–5.2 fold and 1.7–2.6 fold, the concentrations causing 50% mortality (LC₅₀) were higher than the highest test concentration in four soils aged for 150 d. Furthermore, the aging effects correlated significantly with soil amorphous Fe oxides. The EC₅₀ values of Cr significantly differed in ten soils aged for 150 d, ranging from 27 to 512 mg kg⁻¹, which were associated with the variations in reduction and sorption capacity in different soils. Regression analysis indicated that soil clay was the most important single factor predicting soil Cr toxicity to reproduction, and the inclusion of cation exchange capacity in the clay regression could best explain the toxicity variance (87.2%). Additionally, soil pH, organic matter and amorphous Fe oxides could also well explain the toxicity variance (>55%).

25789. 题目: In situ modification provided by a novel wet pyrolysis system to enhance surface properties of biochar for lead immobilization
文章编号: N19030804
期刊: Colloids and Surfaces A: Physicochemical and Engineering Aspects
作者: Nan Zhou, Yifan Wang, Liyang Huang, Jingang Yu, Huanli Chen, Jiajie Tang, Fengjuan Xu, Xiangyang Lu, Mei-e Zhong, Zhi Zhou
更新时间: 2019-03-08
摘要: Surface modification of biochar is significant to obtain more functionalized material for contaminants immobilization. In situ modification, modifying the biochar while the conversion process, was applied by a novel wet pyrolysis system. By using phosphoric acid as working medium, liquid/air interface was created to introduce low content of oxygen, under the control of appropriately settled reaction temperature. Followed with the addition of sodium carbonate to neutralize the system and increase mineral species, effective biochar adsorbent attached with large quantity of acidic oxygenic and phosphoric groups, and carbonate anions was finally produced. The biochar showed excellent decontamination performance of lead with a high adsorption capacity of 316 mg·g^-1 and removal efficiency larger than 95%. The alteration of the characteristics after the adsorption confirmed the adsorption mechanism is the bi-function of surface coordination and precipitation. This novel route is easy handling and energy saving, promising it to be a reliable way to produce biochars with attractive surface properties for environmental decontamination.
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25790. 题目: Aggregation of ferrihydrite nanoparticles: Effects of pH, electrolytes,and organics
文章编号: N19030803
期刊: Environmental Research
作者: Juanjuan Liu, Stacey Marie Louie, Christopher Pham, Chong Dai, Dongli Liang, Yandi Hu
更新时间: 2019-03-08
摘要: To better understand the fate and transport of ferrihydrite nanoparticles (FNPs), which carry many contaminants in natural and engineered aquatic environments, the aggregation of FNPs was systematically investigated in this study. The pH isoelectric point (pH_IEP), surface zeta potential, and particle size evolutions of FNPs were measured under varied aqueous conditions using dynamic light scattering (DLS). The influence of pH (5.0 ± 0.1 and 7.0 ± 0.1), ionic strength (IS), electrolytes (NaCl, CaCl₂ and Na₂SO₄), and organics (humic acid, fulvic acid and CH₃COONa) on the aggregation behaviors of FNPs were explored. Meanwhile, Derjaguin-Landau-Verwey-Overbeek (DLVO) theory was employed to better understand the controlling mechanisms of FNP aggregation. In the presence of sulfate, the surface charge of FNPs was neutralized under varied pH and ionic strength due to ion adsorption and FNPs phase transformation to schwertmannite based on FT-IR results. This phase transformation resulted in rapid aggregation in all water chemistries tested, whereas other salt species affected the aggregation primarily by ion adsorption and charge screening. Presence of increasing concentrations of the organic acids significantly shifted the pH_IEP of FNPs (7.0 ± 0.2) to lower pH (< 4.0) due to adsorption of organics on FNPs surfaces making them negatively charged. The adsorption of HA/FA inhibited FNP aggregation significantly while CH₃COONa did not, due to different effects on steric and/or electrosteric interactions among FNPs by organics with varied pK_a values and molecular weights. After accounting for the important effects of pH, electrolytes, and organics in modifying FNPs’ surface charge, DLVO calculations agreed well with measured critical coagulation concentrations (CCC) values of FNPs at both pH 5.0 ± 0.1 and 7.0 ± 0.1 in the presence of NaCl. This study will hence be useful to better predict and control the fate and transport of FNPs in the presence of electrolytes and organics with different molecular weights, as well as the fate of the associated contaminants in natural and engineered systems.

25791. 题目: Effects of abalone (Haliotis discus hannai Ino) and kelp (Saccharina japonica) mariculture on sources, distribution, and preservation of sedimentary organic carbon in Ailian Bay, China: Identified by coupling stable isotopes (δ¹³C and δ¹⁵N) with C/N ratio analyses
文章编号: N19030802
期刊: Marine Pollution Bulletin
作者: Zhe Pan, Qin-Feng Gao, Shuang-Lin Dong, Fang Wang, Hai-Dong Li, Kun Zhao, Xu-Yang Jiang
更新时间: 2019-03-08
摘要: To investigate the effects of mariculture on the sources, distribution and preservation of sedimentary organic carbon (SOC), sediments from an mariculture area in Ailian Bay, China, and a control area were analyzed for grain size composition, total organic carbon (TOC), total nitrogen (TN), carbon/nitrogen (C/N) ratio, and stable carbon and nitrogen isotopic composition (δ¹³C and δ¹⁵N). The sedimentary type of sediments in study area was clay silt. TOC, TN, C/N, δ¹³C, and δ¹⁵N ranged from 0.58 to 1.21%, 0.06–0.17%, 6.29–9.82, −23.20 to −18.50‰, and 6.17–7.38‰, respectively, and followed similar spatial patterns. TOC, TN and δ¹³C were higher in mariculture area than in control area. Biodeposit and kelp OC contributions greater of SOC in mariculture area than the control area (biodeposits: 20.10 ± 4.84 to 6.2 ± 1.3%; kelp: 15.3 ± 6.63 to 5.2 ± 0.84%). Overall, mariculture activities significantly influence the sources, distribution and preservation of SOC.

25792. 题目: Phosphorus addition alters the response of soil organic carbon decomposition to nitrogen deposition in a subtropical forest
文章编号: N19030801
期刊: Soil Biology and Biochemistry
作者: Xiang-Min Fang, Xiu-Lan Zhang, Fu-Sheng Chen, Ying-Ying Zong, Wen-Sheng Bu, Song-Ze Wan, Yiqi Luo, Huimin Wang
更新时间: 2019-03-08
摘要: The continuous increase of nitrogen (N) deposition may exacerbate phosphorus (P) deficiency, which affects soil organic carbon (SOC) decomposition by changing microbial community characteristics in subtropical forests with highly weathered soils. However, there is currently little information about the role of P and the N × P interaction in SOC dynamics. Here, a field nutrient manipulation experiment was established in a subtropical plantation forest in China. Soils collected from simulated N deposition and P addition treatments for 5 years were incubated at 25 °C for 130 days. Soil microbial composition was measured using the phospholipid fatty acid method and the enzyme activities related to SOC hydrolysis were measured. The SOC concentration and δ¹³C bulk soil and three particle-size fracfractions were also determined. The cumulative CO₂ respired over 9 days, representing the utilization of carbon sources under field conditions, increased with N deposition levels under the without-P treatment, while no significant differences were found among the three N deposition levels in the with-P treatment. Meanwhile, P addition generally suppressed the SOC decomposition during 130 days incubation. Similarly, P addition decreased the potential organic carbon decomposition (C₀) and C₀/SOC ratio. In contrast, C₀ increased with N deposition in the without-P treatment, while was unaffected by N deposition under the with-P treatment, suggesting the response of SOC decomposition to N deposition was affected following P addition by alteration of SOC quality. Moreover, N deposition tended to deplete the δ¹³C of the SOC and P addition enriched the δ¹³C of the macro-particulate organic carbon. Addition of P increased total microbial, fungal and bacterial biomass values by 41.6%, 90.0% and 46.9%, respectively, whereas N deposition had no significant effect. Soil fungi/bacteria ratio significantly increased by N deposition and P addition, which partly explained the reduction of SOC decomposition after P addition. The cellobioside activity significantly decreased by 48.3% after P addition, while cellobioside and β-xylosidase activities increased with N deposition, suggesting that N deposition and P addition had opposite roles in the SOC stability. These results indicate that the positive effect of N deposition on SOC decomposition was suppressed when P was added by changing microbial community and enzyme activity and enhanced P availability may result in increased SOC accumulation under N deposition scenarios in subtropical forests.

25793. 题目: Microbial responses to anthropogenic dissolved organic carbon in Arctic and Antarctic coastal seawaters
文章编号: N19030718
期刊: Environmental Microbiology
作者: Elena Cerro-Gálvez, Paulo Casal, Daniel Lundin, Benjamin Piña, Jarone Pinhassi, Jordi Dachs, Maria Vila-Costa
更新时间: 2019-03-07
摘要: Thousands of semi‐volatile hydrophobic organic pollutants (OPs) reach open oceans through atmospheric deposition, causing a chronic and ubiquitous pollution by anthropogenic dissolved organic carbon (ADOC). Hydrophobic ADOC accumulate in cellular lipids, inducing harmful effects on marine biota, and can be partially prone to microbial degradation. Unfortunately, their possible effects on microorganisms, key drivers of global biogeochemical cycles, remain unknown. We challenged coastal microbial communities from Ny‐ålesund (Arctic) and Livingston Island (Antarctica) with ADOC concentrations within the range of oceanic concentrations in 24 hours. ADOC addition elicited clear transcriptional responses in multiple microbial heterotrophic metabolisms in ubiquitous groups such as Flavobacteriia, Gammaproteobacteria and SAR11. Importantly, a suite of cellular adaptations and detoxifying mechanisms, including remodeling of membrane lipids and transporters, was detected. ADOC exposure also changed the composition of microbial communities, through stimulation of rare biosphere taxa. Many of these taxa belong to recognized OPs degraders. This work shows that ADOC at environmentally relevant concentrations substantially influences marine microbial communities. Given that emissions of organic pollutants are growing during the Anthropocene, the results shown here suggest an increasing influence of ADOC on the structure of microbial communities and the biogeochemical cycles regulated by marine microbes. This article is protected by copyright. All rights reserved.

25794. 题目: Sea ice variability in the southern Norwegian Sea during glacial Dansgaard-Oeschger climate cycles
文章编号: N19030717
期刊: Science Advances
作者: Henrik Sadatzki, Trond M. Dokken, Sarah M. P. Berben, Francesco Muschitiello, Ruediger Stein, Kirsten Fahl, Laurie Menviel, Axel Timmermann, Eystein Jansen
更新时间: 2019-03-07
摘要: The last glacial period was marked by pronounced millennial-scale variability in ocean circulation and global climate. Shifts in sea ice cover within the Nordic Seas are believed to have amplified the glacial climate variability in northern high latitudes and contributed to abrupt, high-amplitude temperature changes over Greenland. We present unprecedented empirical evidence that resolves the nature, timing, and role of sea ice fluctuations for abrupt ocean and climate change 32 to 40 thousand years ago, using biomarker sea ice reconstructions from the southern Norwegian Sea. Our results document that initial sea ice reductions at the core site preceded the major reinvigoration of convective deep-water formation in the Nordic Seas and abrupt Greenland warming; sea ice expansions preceded the buildup of a deep oceanic heat reservoir. Our findings suggest that the sea ice variability shaped regime shifts between surface stratification and deep convection in the Nordic Seas during abrupt climate changes.

25795. 题目: Peroxymonosulfate activation by hydroxylamine-drinking water treatment residuals for the degradation of atrazine
文章编号: N19030716
期刊: Chemosphere
作者: Huijuan Zhang, Xitao Liu, Chunye Lin, Xiaowan Li, Zhou Zhou, Guoxuan Fan, Jun Ma
更新时间: 2019-03-07
摘要: Drinking water treatment residuals (WTRs) have been applied in organic pollutants degradation in water by generating reactive oxygen species from peroxymonosulfate (PMS), however, the slow transformation of Fe(III) to Fe(II) may limit its widespread application. Hydroxylamine (HA) was introduced into the system to enhance the degradation efficiency of atrazine (ATZ) and several key reaction parameters (HA concentration, PMS concentration, pH and temperature) were concerned to study their influence on ATZ degradation. The results revealed that ATZ degradation efficiency was enhanced in the HA/WTRs/PMS system. Effects of some basic inorganic ions (Cl⁻, SO₄²⁻ and NO₃⁻) and natural organic matter on ATZ degradation were investigated and results showed that both have an inhibitory effect on ATZ removal. In addition to the reduction role, HA can also react directly with PMS to produce free radicals that helpful for ATZ degradation. Sulfate radical and hydroxyl radicals were generated and sulfate radical was identified as primary radicals in the HA/WTRs/PMS system by alcohol quenching experiments. Moreover, the HA/WTRs/PMS system also showed good performance for ATZ degradation in authentic water like surface water and groundwater. Introduction of hydroxylamine into the system may promote organic pollutant degradation and use of WTRs as an iron source for PMS activation provides new ideas for sludge treatment.
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25796. 题目: Coupled fenton-denitrification process for the removal of organic matter and total nitrogen from coke plant wastewater
文章编号: N19030715
期刊: Chemosphere
作者: Vahid Razaviarani, Juan A. Zazo, Jose A. Casas, Peter R. Jaffé
更新时间: 2019-03-07
摘要: This work assesses the feasibility of applying a Coupled Fenton-Denitrification (CFD) process for the treatment of wastewater from a coking plant. This highly toxic effluent is characterized by comparable carbon and nitrogen contents and it is usually released into the treatment system at well above room temperature. Recalcitrant organic matter can be easily removed in a first step using Fenton treatment. Working at 50 °C, pH₀: 3, and a wastewater obtained from a coking plant, the stoichiometric amount of H₂O₂ relative to COD and a H₂O₂/Fe²⁺ weight ratio of 50, around 60% of carbon load was mineralized whereas H₂O₂ was completely depleted. However, no changes were observed in the total nitrogen content. A subsequent denitrification stage led to an additional 80% TOC (overall above 90%) and 75% Total Nitrogen removal. This was done in a batch bioreactor at room temperature over 72 h, using a 40-day pre-acclimated denitrifying biomass. These results point to the possibility of designing a combined chemical oxidation and biological treatment to deal with complex effluents containing refractory organic matter including high concentrations of nitrogen species.
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25797. 题目: Relationship of soil fertility with biochemical properties under agricultural practices aimed at controlling land degradation
文章编号: N19030714
期刊: Land Degradation & Development
作者: Ana de Santiago, Ramiro Recena, Francisco Perea‐Torres, María Teresa Moreno, Eusebio Carmona, Antonio Delgado
更新时间: 2019-03-07
摘要: Conservation agriculture (CA) is an essential strategy to avoid agricultural land degradation. It affects nutrient availability to plants and soil biological activity. However, an integral view of the effects of CA on soil fertility and biological indicators has been rarely described. Here, we examined the long‐term effects of no‐till and residue mulching on chemical properties, biological functionality indicators (enzyme activity), and nutrient availability indices of soil, and also their potential relationships, in order to provide a comprehensive view of the effects of CA on soil quality improvement. To this end, we assessed the effects after 27 years of conventional tillage (CT) and no‐tillage (NT) on a Vertisol.

25798. 题目: Influence of land use and land cover change on soil organic carbon and microbial activity in the forests of northern Iran
文章编号: N19030713
期刊: CATENA
作者: Azam Soleimani, Seyed Mohsen Hosseini, Ali Reza Massah Bavani, Mostafa Jafari, Rosa Francaviglia
更新时间: 2019-03-07
摘要: Land-use changes can alter soil carbon (C) contents, and in particular deforestation has been responsible for a large part of the cumulative human-induced greenhouse gas (GHG) emissions. This study aimed to determine the influence of land-use and land cover change on soil organic carbon (SOC) content, microbial biomass C (MBC) and microbial respiration (MR) in the Hyrcanian forests, north of Iran. We compared an agricultural field (AF), plantations of Alnus subcordata (AS), Acer velutinum (AV), Quercus castaneifolia (QC) and Cupressus sempervirens (CS), and a natural forest (NF). Soil samples were collected at three different depths (0–20, 20–40 and 40–60 cm). Results showed that different land covers significantly affected soil characteristics, and SOC increased by 25% and 1.11% after the conversion of NF to CS and AS plantations respectively, and decreased by 4%, 12.11% and 53% when NF was converted to QC, AV and AF respectively. In all treatments, MBC and MR were significantly higher (p < 0.05) in the 0–20 cm depth, and MR was also correlated positively with MBC and SOC. Microbial biomass was near the half in the agriculture field than in plantations and natural forest in the upper layer, but the effects of land use on microbial biomass C decreased with soil depth. However, we observed considerable amounts microbial biomass C in 40–60 cm depth. Also, results showed that topographical feature, altitude and slope, will affect SOC content. Our results indicated that forest plantation is a key measure to enhance SOC content and mitigate global CO₂ emission, especially when soils are degraded and have low soil C content. In particular, afforestation had a crucial effect on elevating SOC content in the Hyrcanian forest, but plantations of oak (QC) and maple (AV) were less effective in terms of soil C increase.
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25799. 题目: Assessing the impacts of land use and land cover changes on soil functions using landscape function analysis and soil quality indicators in semi-arid natural ecosystems
文章编号: N19030712
期刊: CATENA
作者: Mojdeh Safaei, Hossein Bashari, Mohammad Reza Mosaddeghi, Reza Jafari
更新时间: 2019-03-07
摘要: Assessing soil quality indicators is essential for ecosystem function evaluation. This study aimed to compare soil quality indicators of semi-arid forests and rangelands with different condition classes using direct soil quality indicators and landscape function analysis (LFA). Vegetation and soil properties were studied in three forest sites with different densities and 16 rangeland sites. A total of 72 soil samples were collected from various land use/cover types and their physical and chemical properties were measured. Eleven soil quality indicators were assessed from each patch and inter-patch zone along the established transects in each land use/cover type to obtain three functional indices including soil stability, infiltration, and nutrient cycling. The accuracy of the stability and infiltration indices of the LFA was verified by their correlations with some soil quality indicators. The results revealed a similar trend in soil quality indicators among the land use/cover types indicating that soil organic carbon (SOC), particulate soil organic matters (POM), mean weight diameter (MWD), soil stability index (SSI), and macronutrients had more appropriate conditions in rangelands with good conditions and dense forest sites compared to other land uses/covers. The soils in rangelands with poor conditions and sparse forests required substantial input of organic carbon to achieve an appropriate level of soil quality. The results highlighted the importance of SOC, POM, and soil texture for the prediction of aggregate stability in the region. The regression model showed a significant relationship between MWD and SSI. Moreover, nitrogen and SOC had significant relations with nutrient cycling and the relation between water dispersible clay and infiltration index was also significant (p < 0.01). The methods used in this study underscored the importance of conserving natural ecosystems. These methods can be implemented for assessing other semi-arid ecosystems. Holistic land management is required to conserve natural and productive ecosystems and to prevent soil degradation.

25800. 题目: Effect of corn straw biochar application to sediments on the adsorption of 17α-ethinyl estradiol and perfluorooctane sulfonate at sediment-water interface
文章编号: N19030711
期刊: Ecotoxicology and Environmental Safety
作者: Wei Guo, Shaoyong Lu, Jianghong Shi, Xu Zhao
更新时间: 2019-03-07
摘要: The immobilization of organic contaminants in sediment-water systems is of growing concern. Using biochar as sorbent amendment to reduce the mobility of pollutants in the sediment-water interface is becoming increasingly popular as a low-cost and environmentally friendly option. In this study, we mixed sediment from the Weishan Lake with biochar (0%, 2%, and 5% (w/w)) derived from corn straw to investigate the adsorption of perfluorooctane sulfonate (PFOS) and 17α-ethinyl estradiol (EE2). Biochar addition significantly improved the adsorption rates and capacities of EE2 and PFOS on sediments by the factors 1.7–3.5; the organic carbon concentration in the sediment was the main factor influencing this process. The sorption of EE2 and PFOS to sediment was near-linear (Freundlich exponent 1/n of 0.799–0.805), but non-linear for biochar (0.430–0.476) and sediment+biochar (0.370–0.421). The mobility of PFOS in the water-sediment system after biochar addition was significantly reduced, with a considerable increase (about three times) in the sediment-water distribution coefficient K_d. Compared to EE2, PFOS is anionic compound and contains hydrophobic C–F chains and hydrophilic S–O groups, making it more susceptible pH influences and resulting in interactions with–OH, –C=O, Si–O–Si, –O–Si, and –Al–O–Al groups via hydrogen bonding, ligand exchange, and surface complexation. We suggest that biochar amendment at ～5% is a viable approach to immobilize EE2 and PFOS at the sediment-water interface.