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14121. 题目: Characterisation of treated effluent from four commonly employed wastewater treatment facilities: A UK case study
文章编号: N18121213
期刊: Journal of Environmental Management
作者: Christopher A. Yates, Penny J. Johnes, Robert G.M. Spencer
更新时间: 2018-12-12
摘要: Sewage treatment systems are a common feature across the landscape of the United Kingdom, serving an estimated 96% of the population and discharging approximately eleven billion litres of treated wastewater daily. While large treatment facilities are ubiquitous across the landscape, they are not the only method employed in domestic wastewater treatment. This study investigates whether differences in nutrient export (carbon, nitrogen and phosphorus) and organic matter composition (determined by optical indices, SUVA254, S350-400 and E2:E3) from treated effluent could be detected between four of the most common facilities employed in the treatment of wastewater across the UK. Set in the context of the River Wylye, a small headwater catchment, treatment facilities studied included; a septic tank system, small packet treatment works, and two large sewage treatment works, one of which employed phosphorus stripping for phosphorus removal. Inorganic N and P concentrations ranged between 7.51 and 42.4 mg N l−1 and 0.22 and 8.9 mg P l−1 respectively, with DOC concentrations ranging between 1.63 and 11.8 mg C l−1. Optical indices were comparable to those observed in catchments where organic matter is dominated by autochthonous production, suggesting the dominance of low molecular weight material when compared to values observed across temperate aquatic systems. Combining data from both the Environment Agency and Ordinance Survey we estimate that only 15% of domestic properties not connected to mains sewerage in the study catchment have an Environment Agency consent/exemption permit. This calculation suggests that the quantity of small point sources are significantly underestimated, undermining efforts under current legislation to improve stream ecosystem health.
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14122. 题目: Compositional and biogeochemical variations of sediments across the terrestrial-marine continuum of the Baker-Martínez fjord system (Chile, 48°S)
文章编号: N18121212
期刊: Progress in Oceanography
作者: Lorena Rebolledo, Sebastien Bertrand, Carina B. Lange, Fabian J. Tapia, Eduardo Quiroga, Matthias Troch, Nelson Silva, Paola Cárdenas, Silvio Pantoja
更新时间: 2018-12-12
摘要: The Baker-Martínez fjord system (Chile, 48⁰S) is a transitional environment between the terrestrial ecosystems of Patagonia and the SE Pacific Ocean. This unique setting makes it an ideal system to evaluate land-ocean gradients in sediment composition and in a range of biogeochemical variables. Here, we studied the composition and organic geochemistry of surface sediments deposited in the Baker-Martínez fjord system to assess spatial changes in sediment properties and identify the best tracers of terrestrial input. We determined concentrations in biogenic opal, organic carbon, calcium carbonate, and lithogenic particles, and we measured diatom abundance, bulk elemental and isotopic organic geochemistry, and n-alkanes distribution, on a series of surface sediment samples distributed along two proximal-to-distal transects (one in the Martínez Channel and a second one in the Baker Channel). Results reveal clear proximal-to-distal trends in the proportion of freshwater diatoms and in the fraction of organic carbon of terrestrial origin calculated from the bulk organic δ13C measurements. Diatoms are particularly sensitive to freshwater input in proximal environments, whereas bulk organic geochemistry better reflects terrestrial input over long distances across the fjord system. Other terrestrial proxies frequently used in the literature, such as the N/C ratio and the n-alkane-based terrestrial/aquatic ratio, did not show clear variations with distance from the fjord head. Our results suggest that the isotopic composition of bulk organic matter (δ13Corg) and the relative proportion of diatoms of freshwater origin are the best-suited proxies to estimate past changes in terrestrial input from fjord sediment archives, irrespective of the glacial status of the fjord and its watershed.
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14123. 题目: Dynamics of fungal diversity and interactions with environmental elements in response to wheat straw biochar amended poultry manure composting
文章编号: N18121211
期刊: Bioresource Technology
作者: Yumin Duan, Sanjeev Kumar Awasthi, Tao Liu, Hongyu Chen, Zengqiang Zhang, Quan Wang, Xiuna Ren, Zhineng Tu, Mukesh Kumar Awasthi, Mohammad J. Taherzadeh
更新时间: 2018-12-12
摘要: The fungal dynamics and its correlation with physicochemical and gaseous emission were investigated using metagenomics and Heat map illustrator (HEMI). Five different concentrations of wheat straw biochar (WSB) were applied to poultry manure (PM) and composted for 50 days; those without the WSB treatment were used as a control. The results revealed the dominant phyla to be Chytridiomycota, Mucoromycota, Ascomycota and Basidiomycota, while Batrachochytrium, Rhizophagus, Mucor, and Puccinia were the superior genera. In particular, the diversity of Chytridiomycota and Ascomycota was more abundant among all of the treatments. Overall, the diversity of the fungal species was correspondent, but relative abundance varied significantly among all of the composts. Principle Coordinate Analysis (PCoA) and Non-Metric Multi- Dimensional Scaling (NMDS) indicated that different concentrations of WSB applied treatments have significantly distinct fungal communities. In addition, correlation analyses of fungal interactions with environmental elements via HEMI also indicate a clear difference among the treatments. Ultimately, the relative abundance of fungal composition significantly influenced the PM compost treated by the WSB.

14124. 题目: Effects of biochar on growth, and heavy metals accumulation of moso bamboo (Phyllostachy pubescens), soil physical properties, and heavy metals solubility in soil
文章编号: N18121210
期刊: Chemosphere
作者: Ying Wang, Bin Zhong, Mohammad Shafi, Jiawei Ma, Jia Guo, Jiasen Wu, Zhengqian Ye, Dan Liu, Hexian Jin
更新时间: 2018-12-12
摘要: Pot experiment was conducted to investigate the effects of wood biochar (5%), bamboo biochar (5%), rice straw biochar (5%) and Chinese walnut shell biochar (5%) on growth, accumulation of heavy metals in moso bamboo, soil physical properties, and solubility of heavy metals in soil. The results revealed that dry weight of moso bamboo was significantly increased in treatments of wood biochar (5%), rice straw biochar (5%) and Chinese walnut shell biochar (5%) except bamboo biochar (5%). Application of straw biochar (5%) was most effective in enhancing plants biomass, with increase of 157%, 113% and 111% in leaves, roots and stems of moso bamboo. All treatments of biochar have significantly improved soil electrical conductivity with maximum increase of 360% compared to CK. In case of heavy metals accumulation, application of 5% bamboo biochar, straw biochar and Chinese walnut shell biochar has reduced Cu uptake in roots by 15%, 35% and 26%, respectively. The biochars have significantly reduced solubility of soil heavy metals with maximum reduction of 58.91 mg kg−1 and 10.59 mg kg−1 of Cu and Pb with application of rice straw biochar. It is concluded that dry weight of moso bamboo was significantly enhanced by all treatments of biochar except bamboo biochar.

14125. 题目: Coupling interaction between porous biochar and nano zero valent iron/nano α-hydroxyl iron oxide improves the remediation efficiency of cadmium in aqueous solution
文章编号: N18121209
期刊: Chemosphere
作者: Ling Zhu, Lihong Tong, Nan Zhao, Jie Li, Yizhong Lv
更新时间: 2018-12-12
摘要: Based on the interaction between mesoscopic biochar materials and nanomaterials, the synergistic mechanism of the two materials in the process of cadmium remediation was studied. K2CO3 activated porous biochar (KBC) loaded with nano-zero-valent iron (nZVI)/nano-α-hydroxy-iron oxide (nHIO) was studied. Macroscopically, batch adsorption experiments were carried out to describe the adsorption properties of the composites. Microscopically, the changes of surface chemical states were characterized by electron microscopy, XRD, FTIR and XPS. Combining the macroscopic and microscopic characteristics, the synergistic mechanism between biochar and nZVI/nHIO was comprehensively analyzed. The strong synergistic effects between biochar and nano-zero-valent iron (nZVI)/nano-α-hydroxy-iron oxide (nHIO) were found, which improved the removal efficiency of cadmium (Cd) in aqueous solution. The results showed that the loading of nZVI/nHIO reduced the specific surface area to 178.6 m2 g−1 and 272.2 m2 g−1, respectively, but the adsorption capacity of Cd increased to 22.37 mg g−1 and 26.43 mg g−1, respectively, which was more than three times that of KBC (7.02 mg g−1). The interaction between nZVI/nHIO and Cd was enhanced by the complexation of surface functional groups, but the coupling effects were different. The coupling mechanism of Cd on nZVI@KBC was complexation - reduction. Cd was partly reduced in the removal process. While for nHIO@KBC, the existence of Fe (III) on the surface of biochar increased the number and species of oxygen-containing functional groups and enhanced complexation. The existence of synergistic mechanism will provide theoretical basis for the preparation of high efficient nanocomposites and expand the application of nanomaterials in the field of environment.
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14126. 题目: Metals geochemistry and ecological risk assessment in a tropical mangrove (Can Gio, Vietnam)
文章编号: N18121208
期刊: Chemosphere
作者: Nguyen Thanh-Nho, Cyril Marchand, Emilie Strady, Truong-Van Vinh, Tran-Thi Nhu-Trang
更新时间: 2018-12-12
摘要: Mangrove sediments act as natural biogeochemical reactors, modifying metals partitioning after their deposition. The objectives of the present study were: to determine distribution and partitioning of metals (Fe, Mn, Ni, Cr, Cu, Co and As) in sediments and pore-waters of Can Gio Mangrove; and to assess their ecological risks based on Risk Assessment Code. Three cores were collected within a mudflat, beneath Avicennia alba and Rhizophora apiculata stands. We suggest that most metals had a natural origin, being deposited in the mangrove mainly as oxyhydroxides derived from the upstream lateritic soils. This hypothesis could be supported by the high proportion of metals in the residual fraction (mean values (%): 71.9, 30.7, 80.7, 80.9, 67.9, 53.4 and 66.5 for Fe, Mn, Ni, Cr, Cu, Co, and As respectively, in the mudflat). The enrichment of mangrove-derived organic matter from the mudflat to the Rhizophora stand (i.e. up to 4.6% of TOC) played a key role in controlling metals partitioning. We suggest that dissolution of Fe and Mn oxyhydroxides in reducing condition during decomposition of organic matter may be a major source of dissolved metals in pore-waters. Only Mn exhibited a potential high risk to the ecosystem. Most metals stocks in the sediments were higher in the Avicennia stand than the Rhizophora stand, possibly because of enhanced dissolution of metal bearing phases beneath later one. In a context of enhanced mangrove forests destruction, this study provides insights on the effects of perturbation and oxidation of sediments on metal release to the environment.

14127. 题目: Scavenging effect of oxidized biochar against the phytotoxicity of lead ions on hydroponically grown chicory: An anatomical and ultrastructural investigation
文章编号: N18121207
期刊: Ecotoxicology and Environmental Safety
作者: Mostafa F. El-Banna, Ahmed Mosa, Bin Gao, Xianqiang Yin, Hongyu Wang, Zahoor Ahmad
更新时间: 2018-12-12
摘要: To evaluate the scavenging effect of functionalized biochar against the phytotoxicity of Pb2+, original biochar (O-B) was chemically oxidized with either HNO3 or KMnO4 to serve as biofilters (O-BF, HNO3-BF and KMnO4-BF) to hydroponically grown chicory (Cichorium intybus L. var. intybus). Plants subjected to Pb-stress showed various deteriorations in cell organelles including visible alterations in chloroplasts, malformations in plant cells, abnormalities in the mitochondrial system, inward invagination of cell walls, distortions in the plasma membrane, oversized vacuoles and irregular increase in plastoglobuli formation. In addition, disorganization in xylem and phloem tissues and numerous variations in the stomatal number, density and dimensions as well as stomata movement were noticeable in the abaxial leaf surface. Pb-stressed plants showed increments in root diameter, vascular cylinder and metaxylem vessels as well as an obvious increase in the thickness of cortex, intercellular aerenchyma and endodermis layer. Furthermore, a noticeable disturbance in macro-and micronutrient concentrations was recorded in Pb-stressed plants due to the defect in their water status. O-BF showed a limited scavenging effect against the phytotoxicity of Pb2+. However, oxidized biochar filters (particularly KMnO4-BF) recorded a noticeable safeguard effect due to their high affinity to Pb2+ ions. The higher sorption capacity of KMnO4-BF reduced the concentration of Pb in leaf tissues compared to the unequipped filtration treatment (117 vs. 19 µg g−1). In conclusion, data of this hydroponic study provides baseline information regarding the detoxification mechanisms of functionalized biochar against the phytotoxicity of trace elements.

14128. 题目: Estimating the extent of fire induced soil water repellency in Mediterranean environment
文章编号: N18121206
期刊: Geoderma
作者: Thomas Weninger, Vilim Filipović, Mirel Mešić, Brent Clothier, Lana Filipović
更新时间: 2018-12-12
摘要: The fire occurrence in Mediterranean climate regions and the area affected by fire in general are rising due to prolonged drought periods and redistribution of rainfall. This can have effect on soil properties and local scale hydrology by increasing fire induced soil water repellency (SWR). The main objective of our research was to assess the degree of fire induced SWR in the Mediterranean karst area using multiple easy-to-perform field and laboratory methods. The field infiltration measurements were performed with a tension disc infiltrometer (TI) and a minidisc tension infiltrometer (MD) using water and ethanol as an infiltrating liquid on two locations: burnt (B) and control (C, unaffected by fire). Additionally, water drop penetration time test (WDPT), and molarity of ethanol droplet time test (MED) were applied at the laboratory on disturbed and undisturbed soil samples at various depths. All measurements revealed significant differences between burnt and control plots. Infiltration and hydraulic conductivity were reduced and repellency index (RI) was increased at the fire affected sites. The SWR decreased with depth which can be associated with decreasing organic matter and fire burning effect. The WDPT and MED methods in combination with mini disc tension infiltrometer measurements were found useful for the determination of sub-critical SWR. Further research is needed to develop a framework for the quantitative SWR classification, as well as subsequent estimation of the relevance of SWR on critical hydrological processes such as infiltration, runoff, and preferential flow.

14129. 题目: Variations in soil δ13C with alpine meadow degradation on the eastern Qinghai–Tibet Plateau
文章编号: N18121205
期刊: Geoderma
作者: Yunfei Zhao, Xia Wang, Yansheng Ou, Haixia Jia, Jia Li, Changming Shi, Yang Liu
更新时间: 2018-12-12
摘要: The alpine swampy meadow is a unique meadow type on the eastern Tibetan Plateau and is undergoing degradation. However, little is known about the responses of soil δ13C to alpine meadow degradation. Monitoring the β value, which is the slope of the linear regression relating soil δ13C to the logarithm of soil organic carbon (SOC) content, provides an approach to infer SOC dynamics. In this study, we investigated soil δ13C and SOC contents along a soil profile (0–50 cm), together with several soil physicochemical and biomass properties in a swampy meadow (SM), a grassland meadow (GM), and a degraded meadow (DM). Then, the variations in soil δ13C and β values and the main factors affecting them were analyzed. The results showed that soil δ13C increased with soil depth, but SOC decreased. The soil δ13C in the surface layer (0–10 cm) was comparable between GM and DM but was significantly lower in SM, and soil moisture was the major factor influencing the surface soil δ13 value. The three meadow types could be ranked, from highest β value to lowest, as follows: GM > SM > DM. The soil C/N ratio and soil texture explained large proportions of the variations in β value. Our results demonstrated that the degradation of alpine meadows affects biomass and soil physicochemical properties, leading to a reduction in C inputs and an accelerated rate of SOC decomposition, followed by a decrease in SOC content. Our findings also indicated that monitoring changes in soil δ13C is an effective method to evaluate the degradation of alpine meadows, but it should be used with caution. This study provides a more comprehensive understanding of soil δ13C and SOC dynamics with alpine meadow degradation.

14130. 题目: Changes in soil physical and chemical properties after short drought stress in semi-humid forests
文章编号: N18121204
期刊: Geoderma
作者: Qingyin Zhang, Mingan Shao, Xiaoxu Jia, Xiaorong Wei
更新时间: 2018-12-12
摘要: The Loess Plateau region of China is under increasing water shortage due to declining soil water content after reforestation. Thus, assessing the changes in soils properties in reforested lands is critical for sustainable restoration of vegetation. We conducted a continuous rainfall manipulation experiment from June 2015 to November 2016 using mature black locust (Robinia pseudoacacia) on southern Loess Plateau of China. The soil hydrological properties, aggregate distribution and aggregate organic carbon (OC) and total nitrogen (N) concentrations were measured. Two years of drought stress caused a significant decline in saturated hydraulic conductivity and total porosity, but an increase bulk density in the 0–10 cm soil layer. The short drought stress significantly decreased soil aggregate stability due to a decline in macro-aggregate mass. Drought stress significantly decreased total soil OC concentration and macro- and micro-OC or N concentrations, but had no significant effect on total N concentration after two years of drought. Furthermore, the influence of short drought on soil hydrological properties, aggregate distribution and aggregate OC and total N concentrations was mainly evident at the depth of 10 cm. Our results indicated that short drought has the potential to damage soil properties. The results of this study could provide more insight into the sustainability of afforestation in semi-humid areas of China's Loess Plateau.

14131. 题目: Enhancement of excess sludge hydrolysis and decomposition with different lysozyme dosage
文章编号: N18121203
期刊: Journal of Hazardous Materials
作者: Gaige Liu, Ke Wang, Xiangkun Li, Linli Ma, Xiaochen Ma, Hongying Chen
更新时间: 2018-12-12
摘要: The performance of the lysozyme catalysis on excess sludge (ES) hydrolysis and decomposition was investigated in this study. For this purpose, the release of soluble organic matters from sludge flocs, extracellular polymeric substances (EPS) changes in composition and distribution and the quantity variations of microorganisms were monitored. Results indicated that lysozyme boosted the ES hydrolysis significantly with approximately 236.5 mg/L soluble chemical oxygen demand (SCOD), 58.6 mg/L polysaccharide and 662.7 mg/L protein release within 240 min at the lysozyme dosage of 150 mg/gSS. Arising lysozyme dosages (from 0 to 150 mg/gSS step by step) could dramatically enhance the efficiency of the enzyme on ES with the concentration of polysaccharide increased from 84.6 mg/L to 143.2 mg/L and protein increased from 325.0 mg/L to 987.7 mg/L in total EPS. The decomposition effect of lysozyme on microorganisms improved with dosage, about 15.4%, 17.5% and 20.2% bacteria and 56.3%, 57.2% and 65.0% archaea were disintegrated at the lysozyme dosages of 50, 100 and 150 mg/gSS, respectively. However, fungi were barely influenced by the enzymatic catalysis. Tryptophan-protein like substances and aromatic protein were the dominant ES lysis compositions in EPS.

14132. 题目: Priming of pyrogenic C (biochar) mineralization by dissolved organic matter and vice versa
文章编号: N18121202
期刊: Soil Biology and Biochemistry
作者: Andrew R. Zimmerman, Lei Ouyang
更新时间: 2018-12-12
摘要: Due to expected changes in fire frequency and the potential of using pyrolyzed biomass (biochar) amendments to increase soil C storage, there is a need for better ability to predict pyrogenic C (pyC) longevity in soil and its effects on native soil C stability. However, C mineralization from biochar/soil mixtures has been shown to vary greatly and both ‘positive’ and ‘negative’ priming (increased and decreased mineralization of native C, respectively) following biochar amendments have been observed. To better understand the interactions that influence mineralization of pyC and native soil C, bagasse (sugar cane residues) and bagasse biochar pyrolyzed at 300 and 650 °C were incubated in sand over 144 d with soil microbes and dissolved organic matter (DOM) substrates of high and low reactivity (sucrose and humic acid: HA, respectively). Mineralization of particulate and dissolved C was quantified based upon the distinct C isotopic signature of CO2 evolved from each source. Negative priming of bagasse-C mineralization by sucrose (−9.3% cumulative C mineralized) and pyC mineralization by HA (−29 and −68% for low and high temperature biochar, respectively) pointed to the mechanism of ‘substrate switching’, i.e. cases in which added DOM was of greater or similar lability to the particulate OM present. In contrast, positive priming of bagasse mineralization by HA (+77%) and pyC mineralization by sucrose (+271 and 614% for low and high temperature biochar, respectively), was attributed to the mechanisms of soil conditioning (creation of an environment more favourable to microbial growth) and co-metabolism, respectively. Inversely, presence of all the particulates enhanced the mineralization of sucrose (by 8, 58 and 91% for bagasse and low and high temperature biochar, respectively), suggesting a soil conditioning mechanism. In contrast, the biochars had little effect on HA mineralization, likely because of their similar inherent stability and chemistry. These results show that DOM and pyC mineralization in soil is interactive and varies with OM type. Furthermore, the priming observed could be attributed to different mechanisms in different cases, the long term effect of which would likely be greater soil C sequestration than predicted by simple degradation models.
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14133. 题目: Assessment of coastal turbidity improvement potential by terrigenous sediment load reduction and its implications on seagrass inhabitable area in Banate Bay, central Philippines
文章编号: N18121201
期刊: Science of The Total Environment
作者: Takahiro Yamamoto, Mary Ann Cielo L. Malingin, Ma. Marivic Pepino, Masaya Yoshikai, Wilfredo Campos, Toshihiro Miyajima, Atsushi Watanabe, Yoshiyuki Tanaka, Naoko Morimoto, Roseanne Ramos, Homer Pagkalinawan, Kazuo Nadaoka
更新时间: 2018-12-12
摘要: This paper demonstrates the effects of terrigenous sediment load reduction by watershed managements on coastal turbidity in Banate Bay, Iloilo located in central Philippines, using field observations and numerical simulations. Measurements of the total suspended solid and particulate organic carbon indicated that the bulk component of the coastal turbidity comprised terrigenous mineral particles rather than phytoplankton at the rise of the river after heavy rain. The suspended sediment concentration and underwater light intensity were simulated by an atmosphere-watershed-coastal ocean model to investigate the contribution of the terrigenous sediment load to the coastal turbidity in rainy season. The coastal sediment simulation indicated that the turbidity in Banate Bay is highly impacted by terrigenous sediment inputs from distant watersheds, which are transported to the bay by coastal currents. In contrast, the contributions of sediment loads from the adjacent watersheds to the bay turbidity were limited. The simulation also indicated that the majority of the bay is not inhabitable for seagrasses due to limited light availability caused by the high turbidity. Scenario analysis of the sediment load reduction demonstrated that significant reduction of turbidity and improvement of light penetration are conditionally expected only when the remediation is implemented with cooperative management of a series of neighboring watersheds because of the significant contributions of sediment loads from multiple basins.
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14134. 题目: Towards improving the electroanalytical speciation analysis of indium
文章编号: N18121114
期刊: Analytica Chimica Acta
作者: Elise Rotureau, Pepita Pla-Vilanova, Josep Galceran, Encarna Companys, José Paulo Pinheiro
更新时间: 2018-12-11
摘要: The geochemical fate of indium in natural waters is still poorly understood, while recent studies have pointed out a growing input of this trivalent element in the environment as a result of its utilisation in the manufacturing of high-technology products. Reliable and easy-handling analytical tools for indium speciation analysis is, then, required. In this work, we report the possibility of measuring the total and free indium concentrations in solution using two complementary electroanalytical techniques, SCP (Stripping chronopotentiometry) and AGNES (Absence of Gradients and Nernstian Equilibrium Stripping) implemented with the TMF/RDE (Thin Mercury Film/Rotating Disk Electrode). Nanomolar limits of detection, i.e. 0.5 nM for SCP and 0.1 nM for AGNES, were obtained for both techniques in the experimental conditions used in this work and can be further improved enduring longer experiment times. We also verified that AGNES was able (i) to provide robust speciation data with the known In-oxalate systems and (ii) to elaborate indium binding isotherms in presence of humic acids extending over 4 decades of free indium concentrations. The development of electroanalytical techniques for indium speciation opens up new routes for using indium as a potential tracer for biogeochemical processes of trivalent elements in aquifers, e.g. metal binding to colloidal phases, adsorption onto (bio)surfaces, etc.

14135. 题目: The role of hydrodynamic and biogeochemistry on CO2 flux andpCO2 at the Amazon River mouth
文章编号: N18121113
期刊: Biogeosciences
作者: Diani F. S. Less, Alan C. Cunha, Henrique O. Sawakuchi, Vania Neu, Aline M. Valério, Nicholas D. Ward, Daimio C. Brito, Joel E. M. Diniz, William Gagne-Maynard, Carlos M. Abreu, Milton Kampel, Alex V. Krusche, and Jeffrey E. Richey
更新时间: 2018-12-11
摘要: Recent estimates indicate that the lower Amazon River outgasses significant amounts of carbon dioxide (CO2) that was not previously accounted for the global inland water carbon budget. Detailed evaluation of seasonal variability and controlling mechanisms behind the CO2 fluxes in this large and complex area remains incomplete. Previous observations throughout the Amazon basin showed that higher CO2 fluxes (FCO2) and partial pressure of CO2 (pCO2) occur during high water and higher wind intensity seasons. The influence of wind and water speed, depth of water column, as well as respiration of allochthonous and autochthonous organic matter, are frequently assigned as the main control variables. Here, we assess the influence of a set of biogeochemical and hydrodynamic parameters on the seasonal variation of FCO2 and pCO2 near the Amazon River mouth. FCO2, pCO2 and biogeochemical and hydrologic analyses were carried out from 2010 to 2016 during four different hydrological periods per year (N = 25) in the North Channel of the Amazon River mouth. FCO2 and pCO2 were used as independent variables and analyzed against 33 biogeochemical, hydrodynamic and meteorological parameters along the hydrological seasons. The highest FCO2 and pCO2 was obtained at high discharge season (11.28 ± 7.82μmolm−2s−1 and (4575 ± 429μatm, respectively) when most of these parameters tend to be higher. Among the 33 parameters analyzed, the significant correlations with FCO2 and pCO2 (p < 0.05) observed were for water and air temperatures, dissolved oxygen, dissolved organic carbon, nitrate, dissolved inorganic nitrogen and pH. These variables could be considered suitable predictors for estimating pCO2 and FCO2 in the Amazon River mouth area. For a better estimation and understanding of carbon budgets in tropical rivers it is still required to verify and to quantify more deeply the relationship among CO2 evasion and others hydrodynamic, meteorological and biogeochemical variables.

14136. 题目: Atmospheric nitrogen deposition impacts on the structure and function of forest mycorrhizal communities: A review
文章编号: N18121112
期刊: Environmental Pollution
作者: Erik A. Lilleskov, Thomas W. Kuyper, Martin I. Bidartondo, Erik A. Hobbie
更新时间: 2018-12-11
摘要: Humans have dramatically increased atmospheric nitrogen (N) deposition globally. At the coarsest resolution, N deposition is correlated with shifts from ectomycorrhizal (EcM) to arbuscular mycorrhizal (AM) tree dominance. At finer resolution, ectomycorrhizal fungal (EcMF) and arbuscular mycorrhizal fungal (AMF) communities respond strongly to long-term N deposition with the disappearance of key taxa. Conifer-associated EcMF are more sensitive than other EcMF, with current estimates of critical loads at 5–6 kg ha−1 yr−1 for the former and 10–20 kg ha−1 yr−1 for the latter. Where loads are exceeded, strong plant-soil and microbe-soil feedbacks may slow recovery rates after abatement of N deposition. Critical loads for AMF and tropical EcMF require additional study. In general, the responses of EcMF to N deposition are better understood than those of AMF because of methodological tractability. Functional consequences of EcMF community change are linked to decreases by fungi with medium-distance exploration strategies, hydrophobic walls, proteolytic capacity, and perhaps peroxidases for acquiring N from soil organic matter. These functional losses may contribute to declines in forest floor decomposition under N deposition. For AMF, limited capacity to directly access complexed organic N may reduce functional consequences, but research is needed to test this hypothesis. Mycorrhizal biomass often declines with N deposition, but the relative contributions of alternate mechanisms for this decline (lower C supply, higher C cost, physiological stress by N) have not been quantified. Furthermore, fungal biomass and functional responses to N inputs probably depend on ecosystem P status, yet how N deposition-induced P limitation interacts with belowground C flux and mycorrhizal community structure and function is still unclear. Current ‘omic analyses indicate potential functional differences among fungal lineages and should be integrated with studies of physiology, host nutrition, growth and health, fungal and plant community structure, and ecosystem processes.
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14137. 题目: Non-Redfieldian mesopelagic nutrient remineralization in the eastern North Atlantic subtropical gyre
文章编号: N18121111
期刊: Progress in Oceanography
作者: Bieito Fernández-Castro, Beatriz Mouriño-Carballido, Xosé Antón Álvarez-Salgado
更新时间: 2018-12-11
摘要: The eastern boundary of the North Atlantic subtropical gyre (NASTG) receives organic materials produced in the nearby Canary upwelling system (CanUS), which has important implications for the metabolic balance of the region. Here we computed absolute geostrophic, Ekman and eddy diffusive transports and net budgets of oxygen, nitrate, and phosphate, with an inverse model applied to annual climatologies from the World Ocean Atlas 2013, in a large box covering the eastern boundary of the NASTG. The surface waters (<100 m) of the box exported mol O2 m-2 yr-1 to the adjacent ocean and atmosphere, and imported mol N m-2 yr-1 and mmol P m-2 yr-1 of nitrate and phosphate, respectively, indicating that net autotrophy prevailed in the euphotic waters of the eastern NASTG. The central, intermediate and deep waters (100 m-bottom) imported mol O2 m-2 yr-1, and exported mol N m-2 yr-1 and mmol P m-2 yr-1 of nitrate and phosphate, respectively, indicative of net remineralization. Mesopelagic remineralization rates exceeded epipelagic net community production, implying a net deficit of carbon and nutrients in the region. Remineralization occurred at high N:P molar ratios (28) in central waters, and thus, a excess nitrate (DINxs = NO3-16PO4) was produced at a rate of 1011 mol N yr-1. This excess nitrate was exported to the gyre interior, influencing the biogeochemistry of the whole NASTG and leaving the eastern margin with a strong nitrogen deficit, relative to carbon and phosphorus. According to the available literature, the organic carbon export from the CanUS could be sufficient to account for the carbon deficit, but the source of nitrogen remains elusive.

14138. 题目: Performance and microbial community analysis of an algal-activated sludge symbiotic system: Effect of activated sludge concentration
文章编号: N18121110
期刊: Journal of Environmental Sciences
作者: Li Sun, Wei Zuo, Yu Tian, Jun Zhang, Jia Liu, Ni Sun, Jianzheng Li
更新时间: 2018-12-11
摘要: It was focused on the effect of different sludge concentrations on the performances of an algal-activated sludge symbiotic system in terms of wastewater treatment, algal-activated sludge characteristics and community structure. The results showed that the highest nutrient removal efficiencies were obtained in the reactor R2 with soluble chemical oxygen demand (sCOD), ammonia nitrogen (NH4+-N) and phosphate (PO43 − -P) removal efficiencies of (90.6 ± 2.3)%, (97.69 ± 2.6)% and (83.81 ± 2.3)%, respectively. Further investigation exhibited that sludge concentration has a great effect on the dissolved oxygen (DO) concentration, the pH, the growth of algae and the extracellular polymeric substance (EPS) production, which resulted in influencing the settleability and the performance of symbiotic system. The denaturing gradient gel electrophoresis (DGGE) analysis demonstrated that the sludge concentration had a selective power for particular members of algae. Meantime, the stimulated algal population would selectively excite the members of bacteria benefited for the formation of algal-bacterial consortia. The variation of microbial compositions, which was influenced by the different sludge concentrations, might be ultimately responsible for the different treatment performances.
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14139. 题目: Insight into the distribution of metallic elements in membrane bioreactor: Influence of operational temperature and role of extracellular polymeric substances
文章编号: N18121109
期刊: Journal of Environmental Sciences
作者: He Wang, Xiufen Li, Xinhua Wang, Yueping Ren
更新时间: 2018-12-11
摘要: The distribution of metallic elements in a submerged membrane bioreactor (MBR) was revealed at different temperatures using inductively coupled plasma-optical emission spectrometry (ICP-OES), and the role of extracellular polymeric substances (EPS) was probed by integrating scanning electron microscopy (SEM) with confocal laser scanning microscopy (CLSM) over long-term operation. More metallic elements in the influent were captured by suspended sludge and built up in the fouling layer at lower temperature. The concentration of metallic elements in the effluent was 5.60 mg/L at 10°C operational temperature, far lower than that in the influent (51.35 mg/L). The total contents of metallic elements in suspended sludge and the membrane fouling layer increased to 40.20 and 52.19 mg/g at 10°C compared to 35.14 and 32.45 mg/g at 30°C, and were dominated by the organically bound fraction. The EPS contents in suspended sludge and membrane fouling layer sharply increased to 37.88 and 101.51 mg/g at 10°C, compared to 16.87 and 30.03 mg/g at 30°C. The increase in EPS content at lower temperature was responsible for the deposition of more metallic ions. The strong bridging between EPS and metallic elements at lower temperature enhanced the compactness of the fouling layer and further decreased membrane flux. This was helpful for understanding the mechanism of membrane fouling at different operational temperatures and the role of EPS, and also of significance for the design of cleaning strategies for fouled membranes after long-term operation.
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14140. 题目: Tracking the reactivity of ozonation towards effluent organic matters from WWTP using two-dimensional correlation spectra
文章编号: N18121108
期刊: Journal of Environmental Sciences
作者: Xin Jin, Weijie Zhang, Rui Hou, Pengkang Jin, Jina Song, Xiaochang C. Wang
更新时间: 2018-12-11
摘要: The characteristics of effluent organic matter (EfOM) from a wastewater treatment plant (WWTP) during ozonation were investigated using excitation and emission matrix (EEM) spectra, Fourier transform infrared spectroscopy (FT-IR) and high-performance size exclusion chromatography (HPSEC) at different ozone dosages. The selectivity of ozonation towards different constituents and functional groups was analysed using two-dimensional correlation spectra (2D-COS) probed by FT-IR, synchronous fluorescence spectra and HPSEC. The results indicated that ozonation can destroy aromatic structures of EfOM and change its molecular weight distribution (MWD). According to 2D-COS analysis, microbial humic-like substances were preferentially removed, and then the protein-like fractions. Terrestrial humic-like components exhibited inactivity towards ozonation compared with the above two fractions. Protein-like substances with small molecular weight were preferentially reacted during ozonation based on 2D-COS probed by HPSEC. In addition, the selectivity of ozone towards different functional groups of EfOM exhibited the following sequence: phenolic and alcoholic CO groups > aromatic structures containing CC double bonds > aliphatic CH. X-ray photoelectron spectroscopy (XPS) further elucidated the preferential reaction of aromatic structures in EfOM during ozonation.
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