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14001. 题目: Aerobic and Anaerobic Bacterial Mercury Uptake is Driven by Algal Organic Matter Composition and Molecular Weight
文章编号: N18122020
期刊: Environmental Science & Technology
作者: Vaughn Mangal, Benjamin R. Stenzler, Alexandre J. Poulain, Celine Guéguen
更新时间: 2018-12-20
摘要: The biological mobilization of mercury (Hg) into microbes capable of Hg methylation is one of the limiting steps in the formation of the neurotoxin methylmercury (MeHg). Although algal dissolved organic matter (DOM) has been associated with increased MeHg production, the relationship between bacterial Hg uptake and algal DOM remains unexplored. In this study, we aimed to address how the quantity and quality of DOM, freshly harvested from several algae, affected the bacterial uptake of Hg with the use of a biosensor capable of functioning both aerobically and anaerobically. We combined biosensor measurements with high-resolution mass spectrometry and field-flow fractionation to elucidate how DOM composition and molecular weight influenced microbial Hg uptake. We showed that freshly harvested DOM from Chlorophyte and Euglena mutabilis strongly inhibited aerobic and anaerobic Hg uptake, whereas DOM harvested from Euglena gracilis did not exhibit this same pronounced effect. Once fractionated, we found that amino acids and polyamines, most abundant in Euglena gracilis DOM, were positively correlated to increase Hg uptake, suggesting that these molecules are potentially underappreciated ligands affecting Hg bioavailability. As water quality is affected by eutrophication, algal community assemblages will change, leading to variations in the nature of autochthonous DOM released in aquatic systems. Our results highlight that variations in the emergent properties of DOM originating from varying algal species can have a profound effect on bacterial Hg uptake and thus methylation.
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14002. 题目: Effect of light intensity on the characteristics of algal-bacterial granular sludge and the role of N-acyl-homoserine lactone in the granulation
文章编号: N18122019
期刊: Science of The Total Environment
作者: Bing Zhang, Yuan Guo, Piet N.L. Lens, Zhiqiang Zhang, Wenxin Shi, Fuyi Cui, Joo Hwa Tay
更新时间: 2018-12-20
摘要: The effects of light intensity on the development of algal-bacterial granular sludge (ABGS) were investigated over a period of 12 weeks. The ABGS developed at low light intensity (142 ± 10 μmol m−2·s−1) exhibited excellent settling ability (SVI30 of 30.9 mL/g), COD and TN removal efficiencies (97.6% and 60.4%, respectively). High light intensity (316 ± 12 μmol m−2·s−1) accelerated granular biomass growth (5.3 g/L) and enhanced the TP removal efficiency (83.7%). Extracellular polymeric substance (EPS) analysis revealed that low light intensity induced more large weight distribution protein production (9–12 kDa and 50–150 kDa), predominantly tryptophan and aromatic proteins. Furthermore, N-acyl-homoserine lactones (AHLs) with a side chain ≤ C10 were commonly shared in the ABGS, and the ABGS developed at low light intensity had a higher C6- and 3OC8-HSL content, which effectively promoted the biofilm formation. The add-back studies showed that the AHLs facilitated the regulation of EPS synthesis. Statistical analysis indicated that the AHLs content had a close correlation with the EPS production, the 50th percentile of the particle size distribution and microbial community assembly, suggesting that AHLs-mediated quorum sensing have an important ecological role in EPS expression and algal-bacterial granulation. Overall, this study describes the ABGS development at different light intensities and the mechanisms of ABGS formation treating synthetic domestic wastewater.
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14003. 题目: Colloidal stability and aggregation kinetics of biochar colloids: Effects of pyrolysis temperature, cation type, and humic acid concentrations
文章编号: N18122018
期刊: Science of The Total Environment
作者: Wen Yang, Jianying Shang, Prabhakar Sharma, Baoguo Li, Kesi Liu, Markus Flury
更新时间: 2018-12-20
摘要: An understanding of biochar colloid aggregation and stability in aqueous environments is critical for assessing biochar fate and mobility in the soil. The aggregation kinetics of wheat straw-derived biochar colloids pyrolyzed at two temperatures 300 and 600 °C (WB300 and WB600 colloids, respectively) were investigated in monovalent and divalent electrolyte solutions in absence/presence of humic acid (HA). Results show that the critical coagulation concentrations (CCCs) of WB300 colloids in NaCl and CaCl2 solutions were 274 and 61.4 mM, which were higher than those (183 mM for NaCl and 38.1 mM for CaCl2) of WB600 colloids. WB300 had more oxygen-containing functional groups than WB600, which induced more negative surface charge on WB300. HA of 5 mg L−1 greatly increased the CCCs of WB300 and WB600 colloids to 1288 and 806 mM in NaCl solutions, but decreased the CCCs to 54.6 and 37.0 mM in CaCl2 solutions because of strong bridging between HA and Ca2+. In CaCl2 solutions with high salt concentrations (near to the CCCs), different HA concentrations caused distinct effects on the aggregation of biochar colloids. The aggregation of biochar colloids was accelerated by HA with the concentration higher than 5 mg L−1 through cation-bridging while the aggregation was inhibited in the presence of <2.5 mg L−1 HA. Our findings show that pyrolysis temperature used for biochar production had a large effect on the aggregation of biochar colloids in the aqueous environment and that cation type and dissolved natural organic matter are controlling variables.
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14004. 题目: Carbon input and the structural quality of soil organic matter as a function of agricultural management in a tropical climate region of Brazil
文章编号: N18122017
期刊: Science of The Total Environment
作者: Shirlei Almeida Assunção, Marcos Gervasio Pereira, Jean Sérgio Rosset, Ricardo Luiz Louro Berbara, Andrés Calderín García
更新时间: 2018-12-20
摘要: Carbon (C) stabilization and the quality of soil organic matter (SOM) in a tropical climate are key aspects regulating carbon dioxide emissions and maintaining the C cycle. Soil management influences the accumulation of C, regulating the balance between mineralization and/or the humification of SOM. This study aimed to quantify inputs of different chemical forms of C into soil and to evaluate the structural chemical characteristics of humified SOM. Four management systems were established: Forest (F), Pasture (P), Conventional tillage (T), and No-tillage (NT). Total organic carbon (TOC) and nitrogen (TN) by depth, chemical forms of organic matter input, and spectroscopic characterization of SOM in the form of humic acids (HA) were analyzed. The results obtaining by PCA-13C NMR show that the forest accumulated a high amount of C on the surface (surpassing 20 Mg ha−1), favoring the formation of aliphatic HA (CAlkyl-H,R; CAlkyl-O,N; CAlkyl-O). In the NT management that increases biomass in the soil (14 Mg ha−1), the mineralization process occurred to a greater extent, allowing HA to form with a predominance of aromatic structures (CArm-H,R and CArm-O,N). The PCA-FTIR analysis showed that the P system contributed to the formation of similar HA to those under F management. The T management system incorporated the least TOC and TN, with different HA types being formed in these soils than what was found in other managements. Thus, minimally managed and more stabilized systems in tropical climates form HA of structural and compositional similarity, regardless of the nature of C (C3 or C4). In contrast, soils subjected to agricultural uses that promote higher or lower C inputs, form HA that are structurally different from P and F. This study demonstrates the need for developing experiments for model building to elucidate the relationships among C input, management type, and the formation of humic substances.
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14005. 题目: Tracing the sources of nitrate in the rivers and lakes of the southern areas of the Tibetan Plateau using dual nitrate isotopes
文章编号: N18122016
期刊: Science of The Total Environment
作者: Mingming Hu, Yuchun Wang, Pengcheng Du, Yong Shui, Aimin Cai, Cong Lv, Yufei Bao, Yanhui Li, Shanze Li, Panwei Zhang
更新时间: 2018-12-20
摘要: Based on a quantitative analysis of nitrate concentrations, the nitrate sources and temporal variability of the rivers, lakes, and wetlands of Tibet were assessed for the first time using dual isotope technology. Water samples were collected once in July 2017 for analysis of nitrate concentration and isotopic composition. The overall values of δ15N-NO3 and δ18O-NO3 ranged from +1.8‰ to +23.0‰, and from −6.3‰ to +22.2‰ respectively. Duel isotopic composition suggested that nitrification of soil organic nitrogen was the main source of nitrate in the Yalu Tsangpo River. Furthermore, anthropogenic nitrogen inputs become more important in downstream than upstream because of intensive agricultural activities and urban input. In the rivers of the Ngari District, nitrate is mainly derived from desert deposits, manure and sewage, and chemical fertilisers. Different rivers show different characteristics of nitrate sources depending on the location, topography, landform, and climate of the river basins. Animal manure, nitrification of soil organic matter, and desert deposits are mainly responsible for the shifting of nitrate isotopic signatures in lakes, which are minimally affected by human activities. In wetlands, biological nitrification and denitrification could be the main processes of nitrogen migration and transformation. These results provide useful information in revealing the fate of nitrate in different aquatic ecosystems and different areas of Tibet.
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14006. 题目: MP-UV/CaO2 as a pretreatment method for the removal of carbamazepine and primidone in waste activated sludge and improving the solubilization of sludge
文章编号: N18122015
期刊: Water Research
作者: Ming Zheng, Yongmei Li, Qian Ping, Lin Wang
更新时间: 2018-12-20
摘要: Medium-pressure ultraviolet light (MP-UV) combined with calcium peroxide (CaO2) as a pretreatment technology for removing carbamazepine (CBZ) and primidone (PMD) in waste active sludge (WAS) and improving the solubilization of sludge were investigated. CBZ and PMD were effectively removed and the removal fitted pseudo-first kinetics under MP-UV/CaO2 treatment with R2 > 0.97. The higher CaO2 dosage and lower initial volatile suspended solids (VSS) concentration were conductive to the removal of CBZ and PMD. Of the CaO2 hydrolysates, Ca(OH)2 played a more important role than H2O2 during MP-UV/CaO2 treatment. The removal of the target compounds was attributed to direct photolysis and indirect photolysis caused by •OH, 3DOM*, and 1O2, in which •OH played a vital role with > 62.2% contribution to the overall degradation rate. A model predicting the steady concentration of •OH in WAS ([VSS] ≈ 8.6 g L-1) under MP-UV/CaO2 treatment with CaO2 dosage ranging from 0 to 0.5 g g-1-VSS was proposed and validated. Moreover, major intermediates of CBZ and PMD were detected and the probable transformation pathways during MP-UV/CaO2 treatment were proposed. In addition, MP-UV/CaO2 promoted the sludge solubilization effectively. Considering both the pharmaceutical degradation and sludge solubilization, the optimum operation condition with 0.2 g-CaO2 g-1-VSS combined with 7 h MP-UV irradiation is recommended. Under this condition, more than 92.3% of CBZ and 90.3% of PMD were removed, and soluble chemical oxygen demand (SCOD) increased by 657% and 13.6% compared with sole 10 h CaO2 (0.2 g g-1-VSS) treatment and 7 h MP-UV treatment, respectively.
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14007. 题目: Iron cycling and isotope fractionation in terrestrial ecosystems
文章编号: N18122014
期刊: Earth-Science Reviews
作者: Bei Wu, Wulf Amelung, Ying Xing, Roland Bol, Anne E. Berns
更新时间: 2018-12-20
摘要: The cycling of iron (Fe) is often closely linked with that of carbon, nitrogen, phosphorus and manganese. Therefore, alterations in the Fe cycle may be indicative of concurrent overall changes in the biogeochemistry of terrestrial and aquatic ecosystems. Biogeochemical processes taking part in the Fe cycle frequently fractionate stable Fe isotopes, leaving soil, plant and other compartments of the ecosystems with varied Fe isotopic signatures. In this work, we reviewed the Fe isotope fractionation processes that have been reported so far for terrestrial ecosystems. While parent materials vary in Fe isotope compositions, pedogenic processes can further fractionate Fe isotope signatures, resulting in soil profiles with δ56Fe values (relative to isotope standard IRMM-014) from −0.52 to +0.72‰. Different soil Fe pools, as a result of cycling processes, show an even broader range of δ56Fe values, with secondary Fe oxides being isotopically the lightest, and with Fe sequestered in silicate minerals being the heaviest, due to preferential release of light Fe isotopes during dissolution of minerals. Actually and potentially plant-available Fe in soil can be extracted by 0.5 M HCl, which includes pools of water-extractable and exchangeable Fe, organically bound or adsorbed Fe, and poorly crystalline Fe oxides, altogether showing a depletion of heavy Fe isotopes with δ56Fe values down to −1.08‰. Depending on the Fe speciation and concentration present in the growth medium, plants can adapt their uptake strategy for Fe. Plants of the strategy I type especially take up light iron isotopes, while strategy II plants fractionate less towards light isotopes. Aboveground tissues usually show lighter Fe isotope signatures than the roots, with flowers (δ56Fe: −2.15 to −0.23‰) being isotopically the lightest. In freshwater systems, the most distinct Fe isotope fractionation is usually found at the oxic-anoxic interface, where redox conditions change and thus Fe speciation controls the degree of Fe isotope fractionation. Similar to soils, the δ56Fe values of unfiltered water mainly reflect averaged Fe isotope compositions across fractions with different particle sizes. In filtered freshwater (<0.45 μm), isolated colloid-sized fractions can exhibit either positive or negative δ56Fe values, depending on the chosen size fraction and the origin of the (nano) particles, with δ56Fe values up to +2.79‰ for fractions smaller than 0.003 μm from an arctic stream or down to −1.73‰ for dissolved Fe (<0.02 μm) from a boreal forested catchment. Most freshwater studies showed that rivers with elevated contents of dissolved organic carbon (DOC) tend to be isotopically heavier than those with lower DOC contents, while some studies also showed that rivers with high DOC can display light Fe isotopic signatures owing to the input of groundwater- and/or soil water-derived Fe. Finally, anthropogenic impacts can contribute to Fe isotope fractionation in freshwaters and may widen the range of δ56Fe values in the environment, with the lowest records found down to −5.29‰.Overall, our compilation reveals that Fe pools in different terrestrial system compartments vary in stable Fe isotope compositions, although the current database is still small. In order to use stable Fe isotopes as proxies to reconstruct the biogeochemical processes, future works should not solely rely on bulk δ56Fe assessments, but also involve the assessment of different fractionation factors for all biogeochemical pathways, which includes isotopic analyses among various pools of the terrestrial Fe cycle.

14008. 题目: Relationships between the bioavailability of polybrominated diphenyl ethers in soils measured with female C57BL/6 mice and the bioaccessibility determined using five in vitro methods
文章编号: N18122013
期刊: Environment International
作者: Yingxin Yu, Sufang Lou, Xinxin Wang, Shaoyou Lu, Shentao Ma, Guiying Li, Yan Feng, Xinyu Zhang, Taicheng An
更新时间: 2018-12-20
摘要: Several in vitro methods for simulating human gastrointestinal digestion have been validated for predicting the bioavailability of heavy metals, but the methods for successfully predicting the bioavailability of organic pollutants are still limited. In this study, we used an adapted fasting in vitro digestion method (Fa-VDM) from the Simulator of the Human Intestinal Microbial Ecosystem and four other in vitro methods comprising In Vitro Gastrointestinal, a physiologically-based extraction test, the unified BARGE method, and Deutsches Institut für Normung e.V. in order to measure the bioaccessibility of polybrominated diphenyl ethers (PBDEs) in soils from an e-waste dismantling town, China, with a Standard Reference Material (SRM2585) as the control. Furthermore, the bioaccessibility data were compared with the bioavailability measured using female C57BL/6 mice. The bioavailability of PBDEs in the soils and SRM2585 were 1.7% to 38.1% and 3.9% to 48.8%, respectively, and the bioaccessibility determined using Fa-VDM were 1.6–55.4% and 6.7–32.1%. There were negative and parabolic correlations between octanol/water partition coefficient for PBDEs and the bioavailability and bioaccessibility, respectively, whereas the H/C ratios and organic matter contents of the soils did not correlate with them. The bioaccessibility data determined by Fa-VDM were generally higher than those obtained using the other four methods, mainly due to the higher bile concentration and larger liquid to solid ratio in the digestion solution in Fa-VDM. There was a significant linear relationship between the results according to the in vivo and in vitro method of Fa-VDM where the slopes varied from 0.83 to 1.16 (R2 > 0.73) and intercepts from 0.3%–7.7% for BDE47, 99, 100, and 153 measured using Fa-VDM, thereby indicating that the bioaccessibility assessed by this method can potentially be used to predict the bioavailability of moderately brominated congeners in soils.
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14009. 题目: Ultrafiltration membrane fouling performance by mixtures with micromolecular and macromolecular organics
文章编号: N18122012
期刊: Environmental Science: Water Research & Technology
作者: Kuo Gao, Tian Li, Junxia Liu, Bingzhi Dong, Huaqiang Chu
更新时间: 2018-12-20
摘要: Ultrafiltration membrane fouling caused by mixtures of micromolecules (humic acid, HA) and macromolecules (sodium alginate, SA) was studied in a comprehensive manner. The fouling behavior can be divided into two apparent parts according to the HA/SA composition. One part with lower SA composition behaved similarly to HA alone, with the fouling mechanism determined by the standard pore blocking and intermediate pore blocking, while the other part with higher SA composition behaved similarly to SA alone, with the fouling mechanism dominated by the cake filtration. Through the extended Derjaguin–Landau–Verwey–Overbeek (XDLVO) approach, the calculation of the interaction energy showed a significant negative correlation between the total interaction energy and the normalized fouling resistance. Conformably, the results showed that the HA/SA mixture with the dissolved organic carbon mass ratio of 1 : 1 which had the lowest interaction energy barrier exhibited the most severe flux decline.
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14010. 题目: Assessing biochar impact on earthworms: Implications for soil quality promotion
文章编号: N18122011
期刊: Journal of Hazardous Materials
作者: Juan C. Sanchez-Hernandez, Juan Manuel Ríos, Andrés Maximiliano Attademo, Alessio Malcevschi, Ximena Andrade Cares
更新时间: 2018-12-20
摘要: Potential harmful effects of spent coffee grounds (SCGs)-derived biochar on earthworms (Lumbricus terrestris) were investigated through two complementary experiments, which assessed the avoidance response of earthworms to biochar-amended soils (experiment 1), and the response of oxidative stress biomarkers and digestive enzymes (experiment 2). The main results were: 1) the highest dose of biochar (5% w/w) caused a significant avoidance response of earthworms (75% individuals avoided these treated soils after 48 h); 2) signs of oxidative stress were early detected in earthworms exposed to biochar (1 and 5% w/w) as indicated by the integrated biological response index; 3) earthworms exposed to biochar-amended soils for 30 d experienced a significant increase of digestive enzyme activities measured in both the gastrointestinal tissue and the luminal content; 4) interaction between earthworms and biochar led to a higher soil extracellular enzyme activities in the 1% biochar treatment than that of control and 5% biochar treatments. These findings suggest that the joint application of SCG-biochar and L. terrestris is a workable approach for improving soil quality in terms of soil biochemical promotion, although earthworms may develop some physiological mechanisms of biochar tolerance (antioxidant defenses).
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14011. 题目: Origins of sediment organic matter and their contributions at three contrasting wetlands in a coastal semi-enclosed ecosystem
文章编号: N18122010
期刊: Marine Pollution Bulletin
作者: Chunyu Zhao, Zhijian Jiang, Yunchao Wu, Songlin Liu, Lijun Cui, Jingping Zhang, Xiaoping Huang
更新时间: 2018-12-20
摘要: The origins of sediment organic matter (SOM) and their contributions were studied in three contrasting wetlands (mudflat, estuarine and mangrove) of Daya Bay, South China Sea. Lower sediment δ13C but higher δ15N values were observed in coastal wetland than in offshore water of the bay. Greater terrigenous organic matter (TOM) contribution to SOM was observed in lower tidal area in mudflat and estuarine wetland. Higher concentrations of total organic carbon and total nitrogen in the three wetlands, as well as lower sediment δ13C, were found in the wet season. Extremely lower sediment δ15N with higher seawater ammonia were observed in estuarine wetland than in mudflat and mangrove, which was caused by the input of 15N-depleted ammonia from petrochemical industrial wastewater. Mangrove contributed substantially to SOM, with a larger contribution in mangrove area than in non-mangrove area. The mean contribution of TOM to SOM was lower in mangrove than in mudflat.

14012. 题目: High rates of viral lysis stimulate prokaryotic turnover and C recycling in bathypelagic waters of a Ligurian canyon (Mediterranean Sea)
文章编号: N18122009
期刊: Progress in Oceanography
作者: Cinzia Corinaldesi, Eugenio Rastelli, Sara Canensi, Michael Tangherlini, Roberto Danovaro, Antonio Dell'Anno
更新时间: 2018-12-20
摘要: Submarine canyons are able to preferentially channel primary production and shelf export to the deep ocean, thus acting as hotspots of biomass and biogeochemical cycling of organic matter. Despite their global relevance, no information is available about the influence of submarine canyons on deep-sea virus-prokaryote interactions. Here, we show that deep-sea waters overlying the Bisagno Canyon (Ligurian Sea, NW Mediterranean) can sustain up to 4 times higher abundances of bathypelagic prokaryotes and viruses when compared to the waters overlying the adjacent slope. We also report that the bathypelagic waters of the canyon are hotspots of viral infections, with rates of virus-induced prokaryotic mortality and biomass turnover up to 10 times faster compared to the adjacent slope at similar depths. In addition, C released by viral lysis of their prokaryotic hosts in bathypelagic waters of the canyon was up to 40 times higher than in the slope. The prokaryotic distribution in bathypelagic waters of the investigated area of the Ligurian margin was largely influenced by organic C concentrations and temperature. Our results highlight that the peculiar characteristics of the canyons (such as the Bisagno canyon) could contribute to sustain the metabolism of bathypelagic prokaryotes, promoting C cycling through virus-induced prokaryotic mortality. We conclude that submarine canyons could represent hot spots of prokaryotic and viral activities able to support the deep-sea pelagic food webs.

14013. 题目: Variability in the organic carbon stocks, sources, and accumulation rates of Indonesian mangrove ecosystems
文章编号: N18122008
期刊: Estuarine, Coastal and Shelf Science
作者: Mariska A. Kusumaningtyas, Andreas A. Hutahaean, Helmut W. Fischer, Manuel Pérez-Mayo, Daniela Pittauer, Tim C. Jennerjahn
更新时间: 2018-12-20
摘要: Mangrove ecosystems are an important natural carbon sink that accumulate and store large amounts of organic carbon (Corg), in particular in the sediment. However, the magnitude of carbon stocks and the rate of carbon accumulation (CAR) vary geographically due to a large variation of local factors. In order to better understand the blue carbon sink of mangrove ecosystems, we measured organic carbon stocks, sources and accumulation rates in three Indonesian mangrove ecosystems with different environmental settings and conditions; (i) a degraded estuarine mangrove forest in the Segara Anakan Lagoon (SAL), Central Java, (ii) an undegraded estuarine mangrove forest in Berau region, East Kalimantan, and (iii) a pristine marine mangrove forest on Kongsi Island, Thousand Islands, Jakarta. In general, Corg stocks were higher in estuarine than in marine mangroves, although a large variation was observed among the estuarine mangroves. The mean total Corg stock in Berau (615 ± 181 Mg C ha−1) is twice as high as that in SAL (298 ± 181 Mg C ha−1). However, the Segara Anakan Lagoon displayed large within-system variation with a much higher Corg stock in the eastern (483 ± 124 Mg C ha−1) than in the central lagoon (167 ± 36 Mg C ha−1). The predominant accumulation of autochthonous mangrove organic matter likely contributed to the higher Corg stocks in Berau and the eastern SAL. Interestingly, the CAR distribution pattern in SAL is opposite to that of its Corg stocks. The central SAL that receives high sediment inputs from the hinterland has a much higher CAR than the eastern SAL (658 ± 311 g C m−2 yr−1 and 194 ± 46 g C m−2 yr−1, respectively), while Berau has one of the highest CAR (1722 ± 183 g C m−2 yr−1) ever measured. It appears that these large differences are driven by the environmental setting and conditions, mainly sediment dynamics and hydrodynamics, landform, and vegetation conditions. It is inferred that quantifying carbon accumulation in sediments is a useful tool in estimating the present-day carbon storage of mangrove ecosystems. This is a precondition for taking measures under REDD+ (Reducing Emissions from Deforestation and Forest Degradation and the role of conservation, sustainable management of forests and enhancement of forest carbon stocks in developing countries) schemes.

14014. 题目: Degradation of imazapic and imazapyr herbicides in the presence of optimized oil palm empty fruit bunch and rice husk biochars in soil
文章编号: N18122007
期刊: Journal of Hazardous Materials
作者: Saba Yavari, Nasiman B. Sapari, Amirhossein Malakahmad, Sara Yavari
更新时间: 2018-12-20
摘要: Imidazolinones as a persistent and active herbicides group have potential risks to non-target organisms in the environment. Biochar is a carbon-rich sorbent used as an amendment to change soil properties and its microbial communities effective on pesticides degradation rate.The present study was the first to compare empty fruit bunch (EFB) of oil palm and rice husk (RH) biomasses as biochar feedstock for remediation of imidazolinones-contaminated soils. Degradations of imazapic, imazapyr, and a mixture of them (Onduty®) was investigated in the presence of the optimized biochars in the soil during a 70-days incubation. Based on the results, the polar herbicides were resistant to hydrolysis degradation. Photolysis rates of the herbicides reduced significantly in the presence of the biochars in the soil. EFB biochar had greater effects due to its chemical compositions and surface functional groups. Photo-degradation of imazapyr was more affected by biochars amendment. The imidazolinones bio-degradation, however, accelerated significantly with the presence of EFB and RH biochars in soil with the greater effects of RH biochar. It was concluded that the application of the optimized EFB and RH biochars as an innovative sustainable strategy has the potential to decrease the persistence of the imidazolinones and minimize their environmental hazards.

14015. 题目: Soil parameters drive the diversity of Citrus sinensis rhizosphere microbiota which exhibits a potential in plant drought stress alleviation
文章编号: N18122006
期刊: Applied Soil Ecology
作者: Marwa Cherni, Raoudha Ferjani, Francesca Mapelli, Abdellatif Boudabous, Sara Borin, Hadda-Imene Ouzari
更新时间: 2018-12-20
摘要: Plant associated microorganisms, particularly those exhibiting a plant growth promoting (PGP) effect, play an important role in plant nutrition and health and the adaptation to unfavorable climatic conditions, such as drought which threatens the productivity of agricultural crops. The selection of specific microbial populations in the soil habitats associated to plants depends upon the soil physico-chemical parameters besides the ‘rhizosphere effect’ played by each plant species through rhizodepositions. In this study, we investigated the community structure and PGP potential of the microbiota associated to Citrus sinensis plants located in different geographical regions of Tunisia. The bacteria community structure was correlated to soil physiochemical parameters and we identified potassium, carbon and organic matter content as drivers of the C. sinensis microbiota composition. The evaluation of the potential of selected bacteria as biofertilizer and bio-stimulator under drought stress was achieved through the phylogenetic and functional characterization of a large collection of bacterial strains isolated from the rhizosphere of C. sinensis. The strains were screened in vitro for putative plant growth promoting traits, and the six most promising isolates were tested in vivo on Solanum lycopersicum and Capsicum annuum model plants. The bacterized plants were cultivated under drought stress and compared with not bacterized and fully irrigated control plants. All the tested bacteria induced a significant increase in the number of leaves and in root biomass of both plant species compared to not inoculated plants. Our results highlighted that the strains Ensifer adhaerens S1B1.5 and Pseudomonas resinovorans S4R2.6 were, in particular, effective in promoting plant growth under water shortage, indicating them as promising strains for the development of sustainable biofertilizers suited for agriculture in arid and semi-arid regions characterized by water scarcity.

14016. 题目: Effect of nitric acid pre-oxidation concentration on pore structure and nitrogen/oxygen active decoration sites of ethylenediamine -modified biochar for mercury(II) adsorption and the possible mechanism
文章编号: N18122005
期刊: Chemosphere
作者: Boyu Li, Kunquan Li
更新时间: 2018-12-20
摘要: Controlling of pre-oxidation conditions can effectively enhance the aimed active functional groups via promoting the oxidation and grafting reaction on biochar's surface. Here, the effect of different nitric acid pre-oxidation concentration (NAPOC) was investigated on the type and content of active oxygen-containing functional sites during the pre-oxidation stage, as well as the active nitrogen-containing binding sites for the following grafting process. And the possible reaction mechanisms for introducing nitrogen/oxygen-containing functional groups such as amide, pyridinic, carbonyl, carboxyl, etc., into the surface by ethylenediamine (EDA) were proposed. The samples were characterized by various analyses including N2 adsorption/desorption, Boehm titration, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Results showed that the NAPOC played a crucial role in promoting the formation of oxygen-containing initiators, and difference of NAPOC resulted in different reaction principles. At higher NAPOC, more carbonyl, carboxyl and hydroxyl functional groups were formed, which facilitated the decoration of nitrogen binding active sites of amide and pyridinic for mercury ions adsorption into the carbon lattice of mesoporous biomass-derived biochar (MBB). The proportions of micropore and mesopore remained basically unchanged, indicating that the decorated nitrogen/oxygen sites were highly uniformly dispersed in MBB's frame and thus resulted in high activity. The comparison of adsorption properties of MBB showed that MBB-25-EDA had the highest adsorption capacity of 153 mg g−1 at pH 6, confirming that the 25% was the optimum NAPOC for introducing nitrogen/oxygen functional binding sites for effectively anchoring mercury.
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14017. 题目: Influence of algal blooms decay on arsenic dynamics at the sediment-water interface of a shallow lake
文章编号: N18122004
期刊: Chemosphere
作者: Liqing Zeng, Changzhou Yan, Jianhua Guo, Zhuo Zhen, Yuan Zhao, Dapeng Wang
更新时间: 2018-12-20
摘要: Algal blooms decay affects the mobility, bioavailability, and toxicity of arsenic (As) in aquatic environments. The decaying process alters aquatic redox conditions and also introduces ample organic matter, conditions favorable for microbial reduction to simulate As release and As species transformation. This study investigated the role of algae (Microcystis aeruginosa (MA)) blooms decay on the dynamics of labile As and elements associated with its release, such as iron (Fe), manganese (Mn) and sulfide (S), at the sediment-water surface (SWI) of a shallow lake (Lake Taihu) in China, applying mesocosm incubation. A combined AgI/ZrO-Chelex diffusive gradients in thin films (DGT) technology was used to examine labile As, Fe, Mn, and S variations in sediments during none-MA, low-MA, and high-MA treatments. High-MA blooms decay generated strong anoxic conditions, which are favorable for the release of labile As, Fe, Mn, and S from sediment. Labile S produced from the reduction of sulfate caused by decaying MA was likely removed by labile Fe through the formation of Fe-sulfides under reducing conditions. Furthermore, this condition facilitated arsenate (As(V)) reduction to arsenite (As(III)), which was weakly adsorbed by Fe-sulfides and thus mobilized to the aqueous phase. An increase in the sediment resupply of solids As to pore water along with MA blooms decay was also revealed by the DGT-induced fluxes in sediment model, coupled with the average desorption rate constant increasing from 0.27 × 10−6 s−1 to 3.41 × 10−6 s−1, and the average response time decreasing from 7859 s to 1538 s.
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14018. 题目: Coagulation of dissolved organic matter in surface water by novel titanium (III) chloride: Mechanistic surface chemical and spectroscopic characterisation
文章编号: N18122003
期刊: Separation and Purification Technology
作者: Sabir Hussain, John Awad, Binoy Sarkar, Christopher W.K. Chow, Jinming Duan, John van Leeuwen
更新时间: 2018-12-20
摘要: Problems caused by residual organics in treated water include the formation of disinfection by-products (DBP) following reaction with chlorine and being a substrate for microbial regrowth in the drinking water distribution system. Dissolved organic matter (DOM) can only be partially removed by conventional treatment process i.e. coagulation by Al- and Fe-based salts. In the present study, the performance of titanium trichloride (TiCl3) as a coagulant for surface water treatment was studied and compared with conventionally used aluminum sulfate (alum). Jar test experiments were performed at various coagulant doses and pH levels to determine the optimum conditions based on removal efficiencies of dissolved organic carbon (DOC). The zeta potential values were analysed for assessing the destabilisation mechanism of DOM flocs. The TiCl3 showed a significantly higher capacity for DOC removal at pH around 3 at which charge neutralization was found to be the dominant mechanism for the floc formation. This was further evident from the relatively larger floc sizes obtained with TiCl3 treatment. However, destabilization of Ti-flocs occurred at pH 4.5 through an adsorption-enmeshment mechanism due to a highly negative zeta potential. Additionally, fluorescence spectroscopic analyses showed that TiCl3 was more efficient than alum in removing humic compounds. A two-stage treatment process by alum and TiCl3, either as the same chemical or both showed better performance than a single dose treatment. The results indicate that TiCl3 could be an effective alternative coagulant for the treatment of waters, particularly those of low alkalinity and high DOC concentration and low pH wastewaters for removal of hydrophobic compounds and particulate matter.

14019. 题目: Accelerated productions and physicochemical characterizations of different extracellular polymeric substances from Chlorella vulgaris with nano-ZnO
文章编号: N18122002
期刊: Science of The Total Environment
作者: Jinfeng Zhao, Shixiang Liu, Na Liu, Han Zhang, Qiongzhi Zhou, Fei Ge
更新时间: 2018-12-20
摘要: Extracellular polymeric substances (EPS) play significant roles in protecting cells against environmental stresses. However, little information is known about the roles of different EPS in these processes. In this study, the productions and physicochemical characterizations of soluble-EPS (S-EPS) and bound-EPS (B-EPS), the two different fractions of EPS from a green alga Chlorella vulgaris under the stress of ZnO nanoparticle (nano-ZnO) were investigated. The contents of S-EPS and B-EPS which described as dissolved organic carbon, polysaccharides and proteins, both increased with the addition of tested nano-ZnO (0.01 and 0.04 mM) in a 72 h cultivation. EPS-Free (EPS-F) cells produced more S-EPS and B-EPS than the EPS-Cover (EPS-C) cells did with the tested nano-ZnO, especially the contents of protein in the S-EPS of EPS-F cells increased by 45.5% with 0.04 mM nano-ZnO compared to the control at 72 h. Tryptophan-like substances of the protein in S-EPS exhibited a stronger chemical static quenching than tyrosine-like substances with nano-ZnO. In addition, the hydroxyl (OH) as well as carboxyl (CO) group, and CO of amide I, NH/CN of amide II groups in proteins were confirmed that involved in the reaction of S-EPS and B-EPS with nano-ZnO, meanwhile hemiacetal groups in saccharides were oxidized to carboxyl groups. This study could provide a better understanding of EPS in protecting against cells damage with nanoparticles.
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14020. 题目: Effects of aeration rates on the structural changes in humic substance during co-composting of digestates and chicken manure
文章编号: N18122001
期刊: Science of The Total Environment
作者: Junqiu Wu, Yue Zhao, Huimin Yu, Dan Wei, Tianxue Yang, Zimin Wei, Qian Lu, Xu Zhang
更新时间: 2018-12-20
摘要: High humidity and potential threat of pathogen of anaerobic digestates are unfavorable to the environment by direct utilization. To achieve the sustainable utilization of digestates, composting might be a good choice. Meanwhile, the aeration rate of composting has been optimized. Co-composting of digestates and chicken manure was performed under different aeration conditions (0.05, 0.1 and 0.15 L·min−1·kg−1·organic matter (OM)). During composting, internal transformation of humic substance (HS) has been studied for obtaining the potential application value of the co-composting products. Results suggested that the HS concentration was increased by 21.1%, 26.4% and 22.4% with the aeration rates were 0.05, 0.1 and 0.15 L·min−1·kg−1·OM, respectively. The aeration rate of 0.15 L·min−1·kg−1·OM was more conducive to germination. Parallel factor analysis and dimensional correlation spectra (2DCOS) have been combined to reveal the conversion relationships of HS components for understanding the compost application pattern. Hetero-2DCOS indicated that aeration of 0.05 min−1·kg−1·OM and 0.1 L·min−1·kg−1·OM contributed to the formation of complex compounds at long wavelength, and aeration of 0.15 L·min−1·kg−1·OM was beneficial for labile compounds formation at short wavelength. In views of the aeration of 0.1 L·min−1·kg−1·OM was more beneficial to improve HS concentration than 0.05 L·min−1·kg−1·OM, 0.1 L·min−1·kg−1·OM and 0.15 L·min−1·kg−1·OM were consider as the most important aeration rate to conduct digestates composting. Overall, the aeration affected the HS composition which, in turn, might affect the application ways of composting products. This study could provide a reference for industrial composting production and applications.
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