论文检索

主页 | efc软件 | 课题库 | 公众号
:



总访问量:473431

总访客量:24089

关键词:
Organic Matter |
DOM |
POM |
Soil OM |
Sediment OM |
Organic Carbon |
Organic Nitrogen |
Biomarker |
Humic Substances |
Fulvic Substances |
Humins |
Biochar |
Black Carbon |
GDGT |
Lignin |
Free Radical |
...
最新文章  | 
昨日文章 | 
前日文章
期刊:
Agriculture, Ecosystems & Environment |
Agricultural Water Management |
Applied Geochemistry |
Applied Soil Ecology |
Aquatic Geochemistry |
Atmospheric Research |
Biogeochemistry |
Biogeosciences |
Biology and Fertility of Soils |
Bioresource Technology |
CATENA |
Chemical Engineering Journal |
Chemical Geology |
Chemosphere |
CLEAN - Soil, Air, Water |
Colloids and Surfaces A: Physicochemical and Engineering Aspects |
Deep Sea Research Part II: Topical Studies in Oceanography |
Earth-Science Reviews |
Ecological Engineering |
Ecology Letters |
Ecology |
Ecotoxicology and Environmental Safety |
Environment International |
Environmental Earth Sciences |
Environmental Geochemistry and Health |
Environmental Monitoring and Assessment |
Environmental Pollution |
Environmental Research |
Environmental Science & Technology |
Environmental Science and Pollution Research |
Environmental Science: Processes Impacts |
Environmental Science: Water Research & Technology |
Environmental Toxicology and Chemistry |
Estuarine, Coastal and Shelf Science |
European Journal of Soil Science |
Forest Ecology and Management |
Geochimica et Cosmochimica Acta |
Geoderma |
Geophysical Research Letters |
Global Change Biology |
Global Biogeochemical Cycles |
Groundwater |
Harmful Algae |
International Journal of Coal Geology |
Journal of Environmental Chemical Engineering |
Journal of Environmental Management |
Journal of Environmental Sciences |
Journal of Geophysical Research: Biogeosciences |
Journal of Geophysical Research: Oceans |
Journal of Hazardous Materials |
Journal of Membrane Science |
Journal of Soils and Sediments |
Land Degradation & Development |
Limnology and Oceanography |
Marine Chemistry |
Marine Pollution Bulletin |
Nature Communications |
Nature Geoscience |
Ocean Science Journal |
Oikos |
Organic Geochemistry |
Palaeogeography, Palaeoclimatology, Palaeoecology |
Plant and Soil |
Progress in Oceanography |
Quaternary International |
Science of The Total Environment |
Sedimentary Geology |
Separation and Purification Technology |
Soil and Tillage Research |
Soil Biology and Biochemistry |
Waste Management |
Water Research |
Water, Air, & Soil Pollution |
Wetlands |
...

所有论文

9541. 题目: Enhanced removal of Cr(VI) by biochar with Fe as electron shuttles
文章编号: N18072603
期刊: Journal of Environmental Sciences
作者: Jingwen Xu, Yongguang Yin, Zhiqiang Tan, Bowen Wang, Xiaoru Guo, Xia Li, Jingfu Liu
更新时间: 2018-07-26
摘要: Biochar is extensively used as an effective soil amendment for environmental remediation. In addition to its strong contaminant sorption capability, biochar also plays an important role in chemical transformation of contaminant due to its inherent redox-active moieties. However, the transformation efficiency of inorganic contaminants is generally very limited when the direct adsorption of contaminants on biochar is inefficient. The present study demonstrates the role of Fe ion as an electron shuttle to enhance Cr(VI) reduction by biochars. Batch experiments were conducted to examine the effects of Fe(III) levels, pyrolysis temperature of biochar, initial solution pH, and biochar dosage on the efficiency of Cr(VI) removal. Results showed a significant enhancement in Cr(VI) reduction with an increase in Fe(III) concentration and a decrease of initial pH. Biochar produced at higher pyrolysis temperatures (e.g., 700°C) favored Cr(VI) removal, especially in the presence of Fe(III), while a higher biochar dosage proved unfavorable likely due to the agglomeration or precipitation of biochar. Speciation analysis of Fe and Cr elements on the surface of biochar and in the solution further confirmed the role of Fe ion as an electron shuttle between biochar and Cr(VI). The present findings provide a potential strategy for the advanced treatment of Cr(VI) at low concentrations as well as an insight into the environmental fate of Cr(VI) and other micro-pollutants in soil or aqueous compartments containing Fe and natural or engineered carbonaceous materials.
图文摘要:

9542. 题目: Active iron bound to SOM catalyzes H2O2 to oxidize alkanes in soil
文章编号: N18072602
期刊: Environmental Science: Processes Impacts
作者: Jinlan Xu, Qianqian Cao, Miaojia Zhang, Chengwei Yang
更新时间: 2018-07-26
摘要: To explore the oxidation effects and mechanisms for the oxidation of alkanes in the Fenton system by two types of iron bound to soil organic matter (Fe-SOM) catalyzing H2O2 in crude oil contaminated soil, the oxidation experiment was performed in active Fe-SOM and Fe-SOM systems. The results showed that the TPH removal ability of active Fe-SOM (average 0.36 g TPH/g Fe-SOM) was 2.25-fold of the corresponding value of Fe-SOM. Active Fe-SOM contained both -NH2 and -OH functional group, and had higher content of iron with high binding energy, while Fe-SOM only contained -NH2 group. Thus, the large yield of hydroxyl radicals (·OH) was generated (8.92 a.u.) by active Fe-SOM catalyzing H2O2, while the corresponding yield of ·OH in Fe-SOM system was only 4.81 a.u. In addition, the removal efficiency of C17-C23 (70%) were comparable to C24-C30 (69%), not restricted by the hydrophobicity of different alkanes. The alkanes removal in active Fe-SOM was higher than that in Fe-SOM although the content of Fe-SOM was double of active Fe-SOM. In summary, the active Fe-SOM formed by the soil sample containing humic acid-like and hydrophobic acids derivate could catalyze H2O2 to improve the removal efficiency of crude oil in contaminated soil.

9543. 题目: Soil organic carbon depletion and degradation in surface soil after long-term non-growing season warming in High Arctic Svalbard
文章编号: N18072601
期刊: Science of The Total Environment
作者: Philipp R. Semenchuk, Eveline J. Krab, Mattias Hedenström, Carly A. Phillips, Francisco J. Ancin-Murguzur, Elisabeth J. Cooper
更新时间: 2018-07-26
摘要: Arctic tundra active-layer soils are at risk of soil organic carbon (SOC) depletion and degradation upon global climate warming because they are in a stage of relatively early decomposition. Non-growing season (NGS) warming is particularly pronounced, and observed increases of CO2 emissions during experimentally warmed NGSs give concern for great SOC losses to the atmosphere. Here, we used snow fences in Arctic Spitsbergen dwarf shrub tundra to simulate 1.86 °C NGS warming for 9 consecutive years, while growing season temperatures remained unchanged. In the snow fence treatment, the 4-11 cm thick A-horizon had a 2% lower SOC concentration and a 0.48 kg C m−2 smaller pool size than the controls, indicating SOC pool depletion. The snow fence treatment's A-horizon's alkyl/O-alkyl ratio was also significantly increased, indicating an advance of SOC degradation. The underlying 5 cm of B/C-horizon did not show these effects. Our results support the hypothesis that SOC depletion and degradation are connected to the long-term transience of observed ecosystem respiration (ER) increases upon soil warming. We suggest that the bulk of warming induced ER increases may originate from surface and not deep active layer or permafrost horizons. The observed losses of SOC might be significant for the ecosystem in question, but are in magnitude comparatively small relative to anthropogenic greenhouse gas enrichment of the atmosphere. We conclude that a positive feedback of carbon losses from surface soils of Arctic dwarf shrub tundra to anthropogenic forcing will be minor, but not negligible.
图文摘要:

9544. 题目: Order from disorder: do soil organic matter composition and turnover co-vary with iron phase crystallinity?
文章编号: N18072507
期刊: Biogeochemistry
作者: Steven J. Hall, Asmeret A. Berhe, Aaron Thompson
更新时间: 2018-07-25
摘要: Soil organic matter (SOM) often increases with the abundance of short-range-ordered iron (SRO Fe) mineral phases at local to global scales, implying a protective role for SRO Fe. However, less is known about how Fe phase composition and crystal order relate to SOM composition and turnover, which could be linked to redox alteration of Fe phases. We tested the hypothesis that the composition and turnover of mineral-associated SOM co-varied with Fe phase crystallinity and abundance across a well-characterized catena in the Luquillo Experimental Forest, Puerto Rico, using dense fractions from 30 A and B horizon soil samples. The δ13C and δ15N values of dense fractions were strongly and positively correlated (R2 = 0.75), indicating microbial transformation of plant residues with lower δ13C and δ15N values. However, comparisons of dense fraction isotope ratios with roots and particulate matter suggested a greater contribution of plant versus microbial biomass to dense fraction SOM in valleys than ridges. Similarly, diffuse reflectance infrared Fourier transform spectroscopy indicated that SOM functional groups varied significantly along the catena. These trends in dense fraction SOM composition, as well as 14C values indicative of turnover rates, were significantly related to Fe phase crystallinity and abundance quantified with selective extractions. M ssbauer spectroscopy conducted on independent bulk soil samples indicated that nanoscale ordered Fe oxyhydroxide phases (nano-goethite, ferrihydrite, and/or very-SRO Fe with high substitutions) dominated (66–94%) total Fe at all positions and depths, with minor additional contributions from hematite, silicate and adsorbed FeII, and ilmenite. An additional phase that could represent organic-FeIII complexes or aluminosilicate-bearing FeIII was most abundant in valley soils (17–26% of total Fe). Overall, dense fraction samples with increasingly disordered Fe phases were significantly associated with increasingly plant-derived and faster-cycling SOM, while samples with relatively more-crystalline Fe phases tended towards slower-cycling SOM with a greater microbial component. Our data suggest that counter to prevailing thought, increased SRO Fe phase abundance in dynamic redox environments could facilitate transient accumulation of litter derivatives while not necessarily promoting long-term C stabilization.

9545. 题目: ZrO2 nanoparticles confined in metal organic frameworks for highly effective adsorption of phosphate
文章编号: N18072506
期刊: Chemosphere
作者: Tao Liu, Jiankang Feng, Yuqiu Wan, Shourong Zheng, Liuyan Yang
更新时间: 2018-07-25
摘要: Highly dispersed ZrO2 particles confined in the MIL-101 (denoted as MIL-101@Zr(DS)) with varied ZrO2 loading amounts were prepared by the double solvents method. For comparison, ZrO2 loaded MIL-101 samples were synthesized by the conventional impregnation method (denoted as MIL-101@Zr(I)) and the deposition method (denoted as MIL-101@Zr(D)). The characterization results indicated that for MIL-101@Zr(DS), ZrO2 particles were dominantly confined in MIL-101 with a much higher dispersion as compared with MIL-101@Zr(I) and MIL-101@Zr(D). The maximum phosphate adsorption capacity and ZrO2 content normalized phosphate adsorption capacity of the MIL-101@Zr(DS) were 21.28 mg P·g-1 and 1120.0 mg P·g-1, respectively. Additionally, the ZrO2 content normalized phosphate adsorption capacity was significantly larger than that for MIL-101@Zr(I) and MIL-101@Zr(D) as well as the reported values for other Zr-based adsorbents. The effects of solution chemistry on phosphate adsorption to MIL-101@Zr(DS), MIL-101@Zr(I) and MIL-101@Zr(D) were also examined. Compared with MIL-101@Zr(I) and MIL-101@Zr(D), the adsorption of phosphate on MIL-101@Zr(DS) was less affected by the coexistence of anions and dissolved humic acid. Increasing pH from 3 to 12 led to decreased phosphate adsorption capacity of MIL-101@Zr(DS) from 10.38 mg P·g-1 to 2.03 mg P·g-1. Accordingly, used MIL-101@Zr(DS) could be effectively regenerated under alkaline conditions and exhibited stable adsorption-desorption performance.
图文摘要:

9546. 题目: Pre-purification by membrane filtration of paralytic shellfish toxins from Alexandrium minutum dinoflagellate
文章编号: N18072505
期刊: Separation and Purification Technology
作者: Rafik Balti, Nicolas Brodu, Jiaxuan Zhang, Zouher Amzil, Delphine Drouin, Véronique Séchet, Anthony Massé
更新时间: 2018-07-25
摘要: The Paralytic shellfish neurotoxins (PST) are of increasing interest for biomedical applications. The chemical synthesis is often complex and expensive that’s why the purification by membrane filtration of PST from Alexandrium minutum dinoflagellate was investigated. Disrupted micro-alga cells by ultrasonic treatment were diafiltred to let pass toxins through an ultrafiltration membrane. Then, the mean permeate was concentrated and diafiltrated by nanofiltration. Mean permeate fluxes equal to 187, 135 and 135 L.h–1.m-2 were obtained during the first diafiltration, the concentration step and the final diafiltration respectively. Up to 57 % (mol/mol) and 78 % (mol/mol) of organic matters and salts were removed respectively. Divalent ions were sparsely removed contrary to monovalent ones. C1 and C2 toxins were successfully purified since more than 75 % (mol/mol) were recovered. However, only 27 to 50 % (mol/mol) of GTX2, GTX3 and STX were recovered.

9547. 题目: Long-chain n-alkane and n-fatty acid characteristics in plants and soil - potential to separate plant growth forms, primary and secondary grasslands?
文章编号: N18072504
期刊: Science of The Total Environment
作者: Xiaoqing Li, Barbara J. Anderson, Iris Vogeler, Luitgard Schwendenmann
更新时间: 2018-07-25
摘要: Plant-derived lipid molecular proxies can provide insight into present-day soil carbon input and to what extent organic carbon is degraded within soil. To explore whether soil characteristics of ‘primary’ (i.e., native grasslands above the historic treeline) and ‘secondary’ (i.e., human-modified grasslands below the historic treeline) grasslands reflect recent and/or past vegetation input we compared lipid characteristics in modern vegetation and soil from 30 locations around the historic treeline (1150 m) in Central Otago, New Zealand. At each location the dominant plant species and the mineral topsoil (0–10 cm) were analyzed for a range of n-alkane and n-fatty acid proxies. Grass/herbs and trees differed in their total n-alkane concentration (88.9 vs 232.6 μg/g plant dry weight), even-over-odd predominance (EOP, 10.2 vs 18.3) and n-C20/n-C24 ratio (2.2 vs 6.4). Soil samples under all plant growth forms had considerably lower n-alkane and n-fatty concentrations than the corresponding plant samples. Soil under grass/herbs had lower (4.1) odd-over-even predominance (OEP) values compared to soil under trees (10.1) indicating that lipid degradation under grass/herbs cover was higher. Principle component analysis demonstrated that soil lipid characteristics reflected the current vegetation cover. Principal component analysis also revealed a separation between ‘primary’ and ‘secondary’ grasslands. However, further evaluations are required to confirm the validity of lipid proxies in reconstructing the vegetation history of secondary grasslands.
图文摘要:

9548. 题目: Human and veterinary antibiotics during composting of sludge or manure: Global perspectives on persistence, degradation, and resistance genes
文章编号: N18072503
期刊: Journal of Hazardous Materials
作者: Amine Ezzariai, Mohamed Hafidi, Ahmed Khadra, Quentin Aemig, Loubna El Fels, Maialen Barret, Georges Merlina, Dominique Patureau, Eric Pinelli
更新时间: 2018-07-25
摘要: Wastewater treatment plant effluent, sludge and manure are the main sources of contamination by antibiotics in the whole environment compartments (soil, sediment, surface and underground water). One of the major consequences of the antibiotics discharge into the environment could be the prevalence of a bacterial resistance to antibiotic. In this review, four groups of antibiotics (Tetracyclines, Fluoroquinolones, Macrolides and Sulfonamides) were focused for the background on their wide spread occurrence in sludge and manure and for their effects on several target and non-target species. The antibiotics concentrations range between 1 and 136,000 μg kg-1 of dry matter in sludge and manure, representing a potential risk for the human health and the environment. Composting of sludge or manure is a well-known and used organic matter stabilization technology, which could be effective in reducing the antibiotics levels as well as the antibiotic resistance genes. During sludge or manure composting, the antibiotics removals range between 17-100%. The deduced calculated half-lives range between 1 to 105 days for most of the studied antibiotics. Nevertheless, these removals are often based on the measurement of concentration without considering the matter removal (lack of matter balance) and very few studies are emphasized on the removal mechanisms (biotic/abiotic, bound residues formation) and the potential presence of more or less hazardous transformation products.
图文摘要:

9549. 题目: Seasonality alters drivers of soil enzyme activity in subalpine grassland soil undergoing climate change
文章编号: N18072502
期刊: Soil Biology and Biochemistry
作者: Jérémy Puissant, Vincent E.J. Jassey, Robert T.E. Mills, Bjorn J.M. Robroek, Konstantin Gavazov, Sebastien De Danieli, Thomas Spiegelberger, Robert Griffiths, Alexandre Buttler, Jean-Jacques Brun, Lauric Cécillon
更新时间: 2018-07-25
摘要: In mountain ecosystems with marked seasonality, climate change can affect various processes in soils, potentially modifying long-term key soil services via change in soil organic carbon (C) storage. Based on a four-year soil transplantation experiment in Swiss subalpine grasslands, we investigated how imposed climate warming and reduced precipitation modified the drivers of soil carbon enzyme potential activities across winter and summer seasons. Specifically, we used structural equation models (SEMs) to identify biotic (microbial community structure, abundance and activity) and abiotic (quantity and quality of organic matter resources) drivers of soil C-enzymes (hydrolase and oxidase) in two seasons under two different climate scenarios. We found contrasting impacts of the climate manipulation on the drivers of C-enzymes between winter and summer. In winter, no direct effect of climate manipulation (reduced rainfall and warming) on enzyme activity was observed. Yet, climate indirectly down-regulated enzyme activity through a decrease in the availability of water extractable organic carbon (WEOC) labile resources. During summer, reduced soil moisture –induced by the climate manipulation– directly reduced soil microbial biomass, which led to a decrease in C-enzyme activity. In general, across both seasons, neither microbial community structure, nor organic matter quality were strong determinants of enzymatic activity. In particular organic matter recalcitrance (aromaticity) was not found as a general driver of either hydrolase or oxidase C-enzyme potential activities, though we did observe higher C-enzyme activities led to an increase of particulate organic matter recalcitrance in the summer season. Overall, our results highlight the seasonality of climate change effects on soil organic matter enzymatic decomposition, providing a comprehensive picture of seasonal potential cause and effect relationships governing C mineralization in subalpine grasslands.

9550. 题目: Long-term performance of biological ion exchange for the removal of natural organic matter and ammonia from surface waters
文章编号: N18072501
期刊: Water Research
作者: Nargess Amini, Isabelle Papineau, Veronika Storck, Pierre R. Bérubé, Madjid Mohseni, Benoit Barbeau
更新时间: 2018-07-25
摘要: Anionic exchange is an effective treatment option for the removal of natural organic matter from surface waters. However, the management of the spent brine regenerant often limits the adoption of this process. The current study reports one year of operation of ion exchange resins under biological mode (BIEX, i.e. without regeneration to promote biofilm growth on the media) compared to the performance of (i) ion exchange with weekly regeneration (IEX), (ii) granular activated carbon under biological mode (BAC) and (ii) granular activated carbon under adsorption mode (GAC). Four parallel pilot filters (GAC, BAC, IEX and BIEX) were fed with a colored and turbid river water without pretreatment. Although IEX provided the best performance (80% DOC removal) throughout the study, BIEX achieved a similar performance to IEX prior to DOC breakthrough (92 days) and subsequently achieved a mean DOC removal of 62% in warm water conditions. The GAC filter was rapidly exhausted (2 weeks) while the BAC filter only provided a 5% DOC reduction. Full nitrification was observed on both the BIEX and BAC filters under warm water conditions (>15 °C). After one year of operation, BIEX was successfully regenerated with brine. According to a mass balance, 69% of DOC removal in BIEX was due to ion exchange while we assume the remainder was biodegraded. Operation of ion exchange in biological mode is a promising option to reduce spent brine production while still achieving high DOC removal.
图文摘要:

9551. 题目: Effects of short- and long-term exposures of humic acid on the Anammox activity and microbial community
文章编号: N18072437
期刊: Environmental Science and Pollution Research
作者: Khadija Kraiem, Mohamed Ali Wahab, Hamadi Kallali, Andrea Fra-vazquez, Alba Pedrouso, Anuska Mosquera-Corral, Naceur Jedidi
更新时间: 2018-07-24
摘要: Humic acid has a controversial effect on the biological treatment processes. Here, we have investigated humic acid effects on the Anammox activity by studying the nitrogen removal efficiencies in batch and continuous conditions and analyzing the microbial community using Fluorescence in situ hybridization (FISH) technique. The results showed that the Anammox activity was affected by the presence of humic acid at a concentration higher than 70 mg/L. In fact, in the presence of humic acid concentration of 200 mg/L, the Anammox activity decreased to 57% in batch and under continuous condition, the ammonium removal efficiencies of the reactor decreased from 78 to 41%. This reduction of Anammox activity after humic acid addition was highlighted by FISH analysis which revealed a considerable reduction of the abundance of Anammox bacteria and the bacteria living in symbiosis with them. Furthermore, a total inhibition of Candidatus Brocadia fulgida was observed. However, humic acid has promoted heterotrophic denitrifying bacteria which became dominant in the reactor. In fact, the evolution of the organic matter in the reactor showed that the added humic acid was used as carbon source by heterotrophic bacteria which explained the shift of metabolism to the favor of heterotrophic denitrifying bacteria. Accordingly, humic acid should be controlled in the influent to avoid Anammox activity inhibition.

9552. 题目: Molecular insights into reversible redox sites in solid-phase humic substances as examined by electrochemical in situ FTIR and two-dimensional correlation spectroscopy
文章编号: N18072436
期刊: Chemical Geology
作者: Yong Yuan, Xixi Cai, Bin Tan, Shungui Zhou, Baoshan Xing
更新时间: 2018-07-24
摘要: Solid-phase humic substances (also termed humins, HMs) are the largest fraction of humic substances (HSs) in soils and sediments, which are recently shown to be capable of mediating electron transfer in many key biogeochemical processes. However, the redox properties of HMs remains poorly investigated, likely due to their structural complexity and the lack of efficient methodology. Herein, an electrochemical in situ FITR spectroscopic (EC-FTIRS) technique coupled with two-dimensional correlation spectroscopy (2D-COS) was employed for the first time to study the redox process of complex HMs at a molecular level. In situ FTIR identified that the IR bands of quinone and phenolic moieties in the HMs were potential dependent, suggesting that they were the main redox sites in response to the redox transformation of the HMs. Meanwhile, In situ FTIR characterizations showed that the significant variations in IR bands positioned at ~1500 and ~1470 cm-1 in response to the applied potentials, providing evidence for the presence of quinone radical and dianion intermediates during the redox process. The 2D-COS analysis was used to further explore variations in infrared intensities as a function of the potentials applied to reduce or oxidize the HMs, which indicated the occurrence of the typical redox reactions of quinone in the HMs. These results improve our understanding on the redox mechanism of HMs at the molecular level and have significant implication for in-depth understanding of biogeochemical processes.
图文摘要:

9553. 题目: EPS adsorption to goethite: Molecular level adsorption mechanisms using 2D correlation spectroscopy
文章编号: N18072435
期刊: Chemical Geology
作者: Peng Cai, Di Lin, Caroline L. Peacock, Wanxi Peng, Qiaoyun Huang
更新时间: 2018-07-24
摘要: The adsorption of extracellular polymeric substances (EPS) onto soil minerals is an important process for understanding bacterial adhesion to mineral surfaces and environmental cycling of nutrients and contaminants. To clarify the molecular level mechanisms and processes of EPS adsorption, the interaction mechanisms between EPS and goethite was explored using two-dimensional (2D) Fourier transformation infrared (FTIR) correlation spectroscopy (CoS) assisted by C 1s near edge X-ray absorption fine structure spectroscopy (NEXAFS). Results show that the amide functional groups of EPS play an important role in its adsorption on goethite, and the adsorption of EPS-proteins on goethite is a function of electrolyte concentration, with increasing adsorption at a higher electrolyte concentration. Results also show that the order in which the EPS functional groups interact and bind with goethite is dependent on electrolyte concentration, where carboxyl and phosphoryl functional groups are the first to adsorb at low electrolyte concentration, while amide groups are the first to adsorb at higher electrolyte concentration. Deconvolution and curve fitting of the amide I band at the end of the adsorption process (~300 min) shows that the secondary structure of proteins is converted from a random coil conformation to aggregated strands, α-helices and turns. This conversion leads to increased adsorption of EPS-proteins and explains the overall adsorption increase of EPS on goethite surfaces with an increasing concentration of electrolyte. Furthermore, the adsorption of the carboxyl functional groups of EPS decreases with increasing electrolyte concentration, likely due to more effective screening of the goethite surface charge with increasing concentration of electrolyte. The integrated results from ATR-FTIR and 2D-CoS allow us to construct a comprehensive overview of EPS-goethite interaction processes at the molecular level, which can be used to improve our understanding of EPS-mineral interactions in the natural environment. These results also provide fundamental information for a better understanding of bacterial biofilm formation on soil and sediment minerals, and facilitate research on the subsequent interaction of nutrients and contaminants with the reactive constituents of biofilms in natural and contaminated environments.
图文摘要:

9554. 题目: Soil organic carbon storage as a key function of soils - A review of drivers and indicators at various scales
文章编号: N18072434
期刊: Geoderma
作者: Martin Wiesmeier, Livia Urbanski, Eleanor Hobley, Birgit Lang, Margit von Lützow, Erika Marin-Spiotta, Bas van Wesemael, Eva Rabot, Mareike Lie?, Noelia Garcia-Franco, Ute Wollschl?ger, Hans-J?rg Vogel, Ingrid K?gel-Knabner
更新时间: 2018-07-24
摘要: The capacity of soils to store organic carbon represents a key function of soils that is not only decisive for climate regulation but also affects other soil functions. Recent efforts to assess the impact of land management on soil functionality proposed that an indicator- or proxy-based approach is a promising alternative to quantify soil functions compared to time- and cost-intensive measurements, particularly when larger regions are targeted. The objective of this review is to identify measurable biotic or abiotic properties that control soil organic carbon (SOC) storage at different spatial scales and could serve as indicators for an efficient quantification of SOC. These indicators should enable both an estimation of actual SOC storage as well as a prediction of the SOC storage potential, which is an important aspect in land use and management planning. There are many environmental conditions that affect SOC storage at different spatial scales. We provide a thorough overview of factors from micro-scales (particles to pedons) to the global scale and discuss their suitability as indicators for SOC storage: clay mineralogy, specific surface area, metal oxides, Ca and Mg cations, microorganisms, soil fauna, aggregation, texture, soil type, natural vegetation, land use and management, topography, parent material and climate. As a result, we propose a set of indicators that allow for time- and cost-efficient estimates of actual and potential SOC storage from the local to the regional and subcontinental scale. As a key element, the fine mineral fraction was identified to determine SOC stabilization in most soils. The quantification of SOC can be further refined by including climatic proxies, particularly elevation, as well as information on land use, soil management and vegetation characteristics. To enhance its indicative power towards land management effects, further “functional soil characteristics”, particularly soil structural properties and changes in the soil microbial biomass pool should be included in this indicator system. The proposed system offers the potential to efficiently estimate the SOC storage capacity by means of simplified measures, such as soil fractionation procedures or infrared spectroscopic approaches.

9555. 题目: Applications and factors influencing of the persulfate-based advanced oxidation processes for the remediation of groundwater and soil contaminated with organic compounds
文章编号: N18072433
期刊: Journal of Hazardous Materials
作者: Yaoyu Zhou, Xiang Yujia, He Yangzhuo, Yang Yuan, Zhang Jiachao, Luo Lin, Peng Hui, Dai Chunhao, Zhu Feng, Tang Lin
更新时间: 2018-07-24
摘要: Persulfate is the latest oxidant which is being used increasingly for the remediation of groundwater and soil contaminated with organic compounds. It is of great significant to offer readers a general summary about different methods of activating persulfate, mainly including heat-activated, metal ions-activated, UV-activated, and alkaline-activated. Meanwhile, in addition to persulfate concentration as an influencing factor for persulfate oxidation process, selected information like temperature, anions, cations, pH, and humic acid are presented and discussed. The last section focuses on the advantages of different activated persulfate processes, and the suggestions and research needs for persulfate-based advanced oxidation in the remediation of polluted groundwater and soil.
图文摘要:

9556. 题目: Response of treatment performance and microbial community structure to the temporary suspension of an industrial anaerobic bioreactor
文章编号: N18072432
期刊: Science of The Total Environment
作者: Xianchao Qin, Mengmeng Ji, Xiaogang Wu, Chunjie Li, Yueshu Gao, Ji Li, Qiaoyu Wu, Xiaojun Zhang, Zhenjia Zhang
更新时间: 2018-07-24
摘要: In this study, a novel type of mesophilic anaerobic bioreactor—an expanded granular sludge bed (EGSB)—was utilized to explore the effect of suspending reactor operation on the treatment performance and the microbial community structure. The parameters of performance and bacterial community before and after a four-week suspension were compared for the starch processing wastewater treatment bioreactor. The results indicate that the removal rate of the organic matter remained higher than 90%, although the biomass significantly decreased after restarting the reactor. However, the relatively stable microbial community structure before the suspension was altered significantly during the restart and post-running stages. This change was primarily due to variability in satellite species and the substitution effect of different dominant bacteria. For example, some non-major carbohydrate-degrading bacteria that were sensitive to nutrition deficiency, such as Desulfovibrio and Geobacter, were dramatically reduced after the suspension. In contrast, the stress of starvation stimulated the reproduction of hydrolytic bacteria, such as Macellibacteroides. However, the high bacterial diversity index (6.12–6.65) and the longstanding core species, including Chloroflexi, Cloacimonetes, Ignavibacteriae, Thermotogae and Euryarchaeota, maintained the functional stability of the reactor. Consequently, although the total bacteria decreased significantly after reactor operation was suspended, sufficient functional bacteria supported by the high diversity, as well as the longstanding core species, guaranteed the effective degradation after suspension.
图文摘要:

9557. 题目: Recent changes in chironomid communities and hypolimnetic oxygen conditions relate to organic carbon in subarctic ecotonal lakes
文章编号: N18072431
期刊: Science of The Total Environment
作者: Tomi P. Luoto, Marttiina V. Rantala, E. Henriikka Kivil?, Liisa Nevalainen
更新时间: 2018-07-24
摘要: A key question in aquatic elemental cycling is related to the influence of bottom water oxygen conditions in regulating the burial and release of carbon under climate warming. In this study, we used head capsules of Chironomidae larvae to assess community and diversity change between the past (estimated as Pre-Industrial Period) and present and to reconstruct changes in hypolimnetic oxygen conditions from 30 subarctic ecotonal lakes (northeastern Lapland) using the top-bottom paleolimnological approach applying surface sediment (topmost 0–2 cm) and reference (4–5 cm) samples. Subsequently, we tested the findings against dissolved organic carbon (DOC) concentration of the sites. We found that the benthic communities were statistically dissimilar between the past and the present with largest changes occurring in the more transparent oligo-mesohumic lakes. However, murky polyhumic lakes displayed uniformly a decrease in diversity. The chironomid-inferred oxygen values showed a general decrease toward the present with largest shifts in low-DOC lakes, whereas no significant changes were found in the hypolimnetic oxygen conditions of high-DOC lakes, which were often located in wetland areas. These finding suggest that lakes associated with constant organic carbon inputs are more resilient toward climate-induced reductions in hypolimnetic oxygen.
图文摘要:

9558. 题目: Degradation of petroleum hydrocarbons in seawater by simulated surface-level atmospheric ozone: Reaction kinetics and effect of oil dispersant
文章编号: N18072430
期刊: Marine Pollution Bulletin
作者: Haodong Ji, Yanyan Gong, Jun Duan, Dongye Zhao, Wen Liu
更新时间: 2018-07-24
摘要: Oil degradation by surface-level atmospheric ozone has been largely ignored in the field. To address this knowledge gap, this study investigated the ozonation rate and extent of typical petroleum compounds by simulated surface-level ozone, including total petroleum hydrocarbons (TPHs), n-alkanes, and polycyclic aromatic hydrocarbons (PAHs). Moreover, the work explored the effect of a prototype oil dispersant, Corexit EC9500A, on the ozonation rate. Rapid oxidation of TPHs, n-alkanes and PAHs was observed at various gaseous ozone concentrations (i.e. 86, 200 and 300 ppbv). Generally, the presence of the oil dispersant enhanced ozonation of the oil compounds. The addition of humic acid inhibited the reaction, while increasing salinity accelerated the degradation. Both direct ozonation by molecular ozone and indirect oxidation by ozone-induced radicals play important roles in the degradation process. The findings indicate that ozonation should be taken into account in assessing environmental fate and weathering of spilled oil.
图文摘要:

9559. 题目: Monocyclic aromatic hydrocarbons (phthalates and BTEX) and aliphatic components in the SE Mediterranean costal Sea-surface microlayer (SML): Origins and phase distribution analysis
文章编号: N18072429
期刊: Marine Chemistry
作者: Peleg Astrahan
更新时间: 2018-07-24
摘要: Coastal waters are subject to many sources of organic matter, such as land runoff, industrial and urban waste, rivers and atmospheric depositions. Semi-volatile organic compounds (SVOC) are frequently found next to coastal and urban areas. Depending on the specific physical properties of each compound in the SVOC group, these compounds may be adsorbed to particulate matter, evaporate to the atmosphere or accumulate in the sea's uppermost layer - the Sea surface microlayer (SML). Since many of these compounds present health risks, understanding the mechanisms that control the SVOC environmental concentration is crucial, especially in coastal waters.

9560. 题目: Litter crusts promote herb species formation by improving surface microhabitats in a desert ecosystem
文章编号: N18072428
期刊: CATENA
作者: Chao Jia, Ze Huang, Hai-Tao Miao, Rong Lu, Jianjun Li, Yu Liu, Weibo Shen, Honghua He, Gao-Lin Wu
更新时间: 2018-07-24
摘要: The degradation of soil and vegetation substantially damages ecosystem functions. Litter crusts play an active role in the vegetation restoration and management in desert ecosystems. In this study, the effects of litter crusts on surface microhabitats and species formation on sandy land were studied in the wind-water erosion crisscross region in the Mu Us Desert, northwest China. Soil microhabitat features including moisture, temperature, and organic matter content were measured in different positions of litter crusts and bare sand, seedling species richness, and total seedling number of all species were recorded in litter crusts on the sand's surface. The results showed that there were significant differences between litter crusts and bare sand in terms of soil moisture, temperature, organic matter content, and light intensity. Compared with that of bare sand, soil moisture below litter crusts was increased by an average of 17.0% overall, soil organic matter content was increased by 77.5% at the 0–5 cm depth and by 80.8% at the 5–10 cm depth. Litter crusts decreased soil temperature and light intensity by an average of 16.6% and 31.6%, respectively. Seedling species richness and total seedling number of all species were significantly higher in litter crusts than those in bare sand. Our findings revealed that litter crusts modify the surface microhabitats of sand by maintaining soil moisture, regulating soil temperature, increasing soil nutrients, and reducing light intensity, thus promoting species establishment in the wind-water erosion crisscross region.

 共 10199 条记录  本页 20 条  本页从 9541-9560 条  478/510页  首页 上一页  473 474 475 476 477 478 479 480 481 482 483  下一页  末页   

本数据库数据来源自各期刊,所有权归属各期刊。数据仅供分享学习,不作商业用途,特此申明。