论文检索

主页 | efc软件 | 课题库 | 公众号
:



总访问量:362644

总访客量:20380

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

121. 题目: Adsorption mechanism of cadmium on microplastics and their desorption behavior in sediment and gut environments: The roles of water pH, lead ions, natural organic matter and phenanthrene
文章编号: N20072213
期刊: Water Research
作者: Yanfei Zhou, Yuyi Yang, Guihua Liu, Gang He, Wenzhi Liu
更新时间: 2020-07-22
摘要:

Microplastics (MPs) in aquatic systems can act as a vector for various toxic contaminants, such as metal ions. Although some studies have investigated the adsorption characteristics of metal ions on MPs, the desorption behaviors of metal ions from MPs in different environments are largely unknown. Here, the adsorption of cadmium (Cd(II)) onto five different types of MPs were compared to examine the relationship between the surface characteristics and the adsorption properties of MPs. Our results showed that polyamide had the highest Cd(II) adsorption capability with a value of 1.70 ± 0.04 mg/g, followed by polyvinyl chloride (1.04 ± 0.03 mg/g), polystyrene (0.76 ± 0.02 mg/g), acrylonitrile butadiene styrene (0.65 ± 0.02 mg/g) and polyethylene terephthalate (0.25 ± 0.01 mg/g). The specific surface area and total pore volume were closely correlated with the adsorption capacity of the MPs, and the π–π interaction, electrostatic interaction and oxygen-containing functional groups played crucial roles in the adsorption of Cd(II) onto the MPs. The sorption capabilities of Cd(II) onto the MPs first increased and then decreased with increasing solution pH from 2.0 to 9.0. In addition, the adsorption capacities were suppressed with the presence of lead ions (20–80 mg/L), while the coexistence of phenanthrene had a minor impact. Interestingly, the presence of humic acid promoted the desorption of Cd(II) from the MPs both in the synthetic earthworm gut and in the sediment system. A higher desorption rate was observed in the simulated gut environment, suggesting that metal-contaminated MPs would pose higher ecological risks to macroinvertebrates. Overall, our findings provide a better understanding of the sorption mechanism of Cd(II) onto MPs and the desorption behavior under different environmental conditions in aquatic ecosystems.

122. 题目: Magnetic nanocomposite microbial extracellular polymeric substances@Fe3O4 supported nZVI for Sb(V) reduction and adsorption under aerobic and anaerobic conditions
文章编号: N20072212
期刊: Environmental Research
作者: Jixian Yang, Lu Zhou, Fang Ma, Heping Zhao, Fengxia Deng, Shanshan Pi, Aiqi Tang, Ang Li
更新时间: 2020-07-22
摘要:

The extracellular polymeric substances coating magnetic powders-supported nano zero-valent iron (@Fe3O4) was synthesized, using reduction and adsorption to treat Sb(V) wastewater. The adsorption performance and mechanism were investigated under aerobic and anaerobic conditions. The adsorption capacity of @Fe3O4 (79.56 mg/g at pH = 5) was improved compared to that of the original materials (60.74 mg/g). The spectral analysis shows that both nZVI and 3O4 in @Fe3O4 played an important role in reducing Sb(V) to Sb(III) and adsorbing Sb. The reducibility and adsorption capacity of @Fe3O4 towards Sb(V) remained strong under aerobic condition (62% Sb(III), 79.56 mg/g), although they were slightly weaker than those under anaerobic condition (74% Sb(III), 91.78 mg/g). @Fe3O4 showed good performance in regeneration experiments. @Fe3O4 is promising as a cost-effective and highly efficient material for Sb(V)-contaminated water. This study is meaningful in understanding the redox behaviour of nZVI composites in aerobic and anaerobic conditions.

123. 题目: Spatial and temporal comparisons of dissolved organic matter in river systems of the Three Gorges Reservoir region using fluorescence and UV–Visible spectroscopy
文章编号: N20072211
期刊: Environmental Research
作者: Yongmei Ma, Siyue Li
更新时间: 2020-07-22
摘要:

Understanding optical characteristics, composition and source of dissolved organic matter (DOM) in rivers of the Three Gorges Reservoir (TGR) region is important for region and global carbon cycle. However, chemical compositions and source of DOM from the tributary to mainstream in the TGR region are not well studied. Consequently, 126 water samples were collected from rivers in different land use region, and these rivers covered the main tributaries of the Yangtze River in the TGR region. The temporal and spatial variations of DOM structure and source identification in different land use region were investigated using UV–visible absorbance and fluorescence spectroscopy. Overall, there were higher ratio of humic acid to fulvic, aromaticity, molecular weight and proportion of colored humic substances in DOM in the wet season than in the dry season. The weaker biologic/microbial and stronger terrestrial sources in DOM were observed in the wet season than in the dry season. DOM comparison in variable land use demonstrated the higher terrestrial sources and weaker biologic/microbial sources in DOM in the forest-affected rivers irrespective of hydrological seasonality, as well as in the wet season irrespective of land use types. DOM in the farmland-affected rivers showed more protein-like signal. We found that monsoonal precipitation, anthropogenic activities and land use were important drivers for the DOM quality variations. These findings will be beneficial to unravel riverine DOM structure and sources in relation to anthropogenic activities and also improve our understanding of DOM biogeochemical cycle in the rivers.

124. 题目: Influence of surface hydrophobicity/hydrophilicity of biochar on the removal of emerging contaminants
文章编号: N20072210
期刊: Chemical Engineering Journal
作者: Adam M. Clurman, Oscar M. Rodríguez-Narvaez, Ayomi Jayarathne, Gehan De Silva, Mahinda I. Ranasinghe, Ashantha Goonetilleke, Erick R. Bandala
更新时间: 2020-07-22
摘要:

This study investigated the removal of Acetaminophen (ACT) using biochars having different physicochemical characteristics. Biochars subjected to post-pyrolysis heat-treatment at 300 °C for different treatment times (0, 3.5, 8 and 24 h) were used. The resulting biochars were characterized using FTIR and X-ray diffraction spectroscopy. Experiments for ACT adsorption with different biochars loads (0.0, 0.05, 1, and 2 g L−1) were performed. Using the best performing material, ACT adsorption was investigated for additional biochar loads (4.0, and 6.0 g L−1) and experiments to test the effect of ionic strength were undertaken for different ions (chloride, carbonate, and nitrate) at three different concentrations (0.0, 1.0, 5.0 mM). The results showed that the changes to the surface of the thermally treated biochars increased the adsorption of ACT. The changes in the amount of oxygen-containing functional groups on the surface of the modified biochars (e.g., CO from 47.8 a.u. to 152 a.u. in the untreated and thermally treated biochars, respectively), as well as modifications to their crystalline structure are considered to be the reason for the observed improvement. Adsorption isotherms and kinetic models suggest the generation of an adsorbate monolayer and chemisorption as the rate-limiting step. The different anions tested were found to have a significant influence on ACT adsorption, related to their electronegativity and steric effect, as confirmed by the multivariate analysis.

125. 题目: An optimized method for studying fungal biomass and necromass in peatlands via chitin concentration
文章编号: N20072209
期刊: Soil Biology and Biochemistry
作者: Sylwia Adamczyk, Tuula Larmola, Krista Peltoniemi, Raija Laiho, Torgny Näsholm, Bartosz Adamczyk
更新时间: 2020-07-22
摘要:

Peatlands store a significant carbon (C) pool but global warming promotes growth of woody plants, which may affect the C balance of peatlands. As shrubs and trees form symbioses with mycorrhizal fungi, which are potentially effective decomposers of recalcitrant organic matter, suitable tools to measure fungal biomass, necromass and turnover rates are needed. Here we present a method optimized for studying chitin, a marker of living and dead fungal mass in peatland ecosystems. Optimizations include enhancement of purification steps, which enabled measurements of chitin concentration from both peat and from mycorrhizal mycelia in ingrowth bags with quartz sand. Adjustments proposed here will enable studying the role of fungi in peatland ecosystems.

126. 题目: Drought accelerated recalcitrant carbon loss by changing soil aggregation and microbial communities in a subtropical forest
文章编号: N20072208
期刊: Soil Biology and Biochemistry
作者: Xueling Su, Xin Su, Guiyao Zhou, Zhenggang Du, Songchen Yang, Mengying Ni, Hua Qin, Zhiqun Huang, Xuhui Zhou, Jie Deng
更新时间: 2020-07-22
摘要:

Subtropical forests are considerable carbon (C) sinks in Asia, yet are facing the threat of drought with increased frequency and prolonged duration. Drought may directly and indirectly impact soil C cycling, potentially affecting the fate of the soil organic carbon (SOC) storage. In a subtropical evergreen broad-leaved forest of eastern China, five years of rainfall reduction experiment resulted in an average of 52.6% decrease in soil water content. In this study, the responses of SOC composition, soil aggregate stability, microbial extracellular enzymatic activities, fungal and bacterial community structures under long-term drought were assessed. Our results showed that drought resulted in loss of a third of large macroaggregates, and doubled the proportion of microaggregates. The non-hydrolyzed carbon (NHC) content decreased by over 50% in large macroaggregates, leading to increased sensitivity of SOC to decomposition. Compared with fungi, bacteria were more sensitive to drought. The majority of the affected taxa showed reduced abundances, while that of Actinobacteria, a group commonly associated with recalcitrant C degradation, significantly increased. Drought also increased the overall peroxidase activity typically involved in recalcitrant C turnover, although it reduced hydrolytic enzyme activities in macroaggregates. These findings revealed that drought not only decreased SOC stability through macroaggregate disintegration and changing its chemical characteristics, but also shifted microbial communities in both composition and activities toward enhanced abilities of recalcitrant C conversion. This study highlights the importance of understanding microbially-mediated C turnover processes to better predict the fate of SOC storage in response to long-term drought.

127. 题目: Monitoring the nitrous oxide emissions and biological nutrient removal from wastewater treatment: Impact of perfluorooctanoic acid
文章编号: N20072207
期刊: Journal of Hazardous Materials
作者: Hongbo Chen, Mei Zou, Yaoyu Zhou, Long Zeng, Xiao Yang
更新时间: 2020-07-22
摘要:

The impacts of perfluorooctanoic acid (PFOA) on biological nutrient removal and nitrous oxide (N2O) emissions have been specifically studied. The experimental results show that PFOA inhibited nitrification, but promoted denitrification and reduced N2O emissions without significantly affecting phosphorus removal. The existence of 20 mg/L of PFOA increased total nitrogen removal efficiency from 78.7 ± 6.89 % to 86.8 ± 6.39 % and reduced N2O emission factor from 6.02 ± 0.24 % to 4.43 ± 0.10 %. The mechanism studies reveal that microorganisms released extracellular polymeric substances (EPS) under PFOA exposure to protect sludge cells against PFOA toxicity. The generated PFOA-EPS conjugates reduced the nitrification rate, but increased the denitrification rate by regulating the activity of oxidoreductases. In addition, PFOA reduced the activity of polyphosphate accumulating organisms and glycogen accumulating organisms to save carbon source for denitrification, which reduced the electronic competition between reductases, thereby achieving complete denitrification and N2O mitigation. The promotion of PFOA for denitrification and N2O mitigation can gain a more comprehensive cognition of the role of PFOA in wastewater treatment. The release mechanism of EPS can afford new insights for the development of effective methods to enhance nitrogen removal and reduce N2O emissions.

128. 题目: The interaction laws of atmospheric heavy metal ions and water-soluble organic compounds in PM2.5 based on the excitation-emission matrix fluorescence spectroscopy
文章编号: N20072206
期刊: Journal of Hazardous Materials
作者: Xiaobo Wang, Yuanyuan Qin, Juanjuan Qin, Yanrong Yang, Ting Qi, Rongzhi Chen, Jihua Tan, Kang Xiao
更新时间: 2020-07-22
摘要:

The excitation-emission matrix (EEM) fluorescence spectroscopy was used to characterize the fluorescence properties of water-soluble organic compounds (WSOCs) in PM2.5 coupled with parallel factor analysis (PARAFAC). Three main components of WSOCs were extracted from PM2.5, i.e., humic-like (fulvic acid-like and humic acid-like) substances (HULIS), and soluble microbial by-product-like or aromatic protein-like, respectively. A fluorescence quenching experiment was designed to systematically analyze the interaction laws of atmospheric heavy metal ions and WSOCs in PM2.5. Our study revealed HULIS, especially the humic acid-like substances, might be principal substances binding with metal ions and the strength of interactions was related to the types and concentrations of metal ions. Furthermore, EEM was a powerful tool to understand the interaction laws of atmospheric heavy metal ions and WSOCs in PM2.5. This work implied that the interactions of atmospheric heavy metal ions and WSOCs might directly or indirectly play a significant role in atmospheric environment and public health.

129. 题目: Revegetation type drives rhizosphere arbuscular mycorrhizal fungi and soil organic carbon fractions in the mining subsidence area of northwest China
文章编号: N20072205
期刊: Catena
作者: Yinli Bi, Li Xiao, Chen Guo, Peter Christie
更新时间: 2020-07-22
摘要:

The rhizosphere arbuscular mycorrhizal fungal (AMF) community and soil organic carbon (SOC) fractions are important in vegetation restoration because they can promote plant growth and environmental improvement in the mining subsidence area of northwest China. However, the effects of revegetation type on SOC fractions and the AMF community remain poorly understood despite their importance in promoting sustainable environmental development. Here, we have examined the rhizosphere soil AMF community and SOC fractions of five revegetation types comprising Amorpha fruticosa (AF), Hippophae rhamnoides (HR), Xanthoceras sorbifolium (XS), Cerasus humilis (CH), and Cerasus szechuanica (CS). Revegetation type significantly affected AMF α-diversity, communities and SOC fractions. The contents of soil microbial biomass carbon, dissolved organic carbon, readily oxidized organic carbon and readily extractable glomalin were maximum in HR. We found six genera of AMF (Glomus, Scutellospora, Paraglomus, Claroideoglomus, Ambispora and Diversispora) and Glomus was the most frequently occurring genus in each revegetation type. Nitrogen-fixing plants (AF and HR) may release large amounts of soil nutrients to promote the activity of the soil AMF community. Soil pH, SOC and C:N ratio play key roles in shifting the AMF community. Interactions between the soil AMF community and revegetation types are key to optimizing the restoration of degraded systems and accumulating soil organic matter. Our observations may provide fundamental guidelines in the assessment of ecosystem services and sustainable development in vegetation reconstruction in the coal mining subsidence areas.

130. 题目: Seasonal variations of nitrogen in permafrost-affected soils of the Qinghai-Tibetan Plateau
文章编号: N20072204
期刊: Catena
作者: Meizhen Xie, Lin Zhao, Xiaodong Wu, Liming Tian, Guangyang Yue, Huayun Zhou, Zhenming Wu
更新时间: 2020-07-22
摘要:

The largest permafrost area in China is on the Qinghai-Tibetan Plateau (QTP), and the nitrogen biogeochemical cycles in this area have received significant attention. However, there is insufficient knowledge of the available soil nitrogen and microbial biomass nitrogen (MBN) dynamics in this region, which hinders our understanding of the changes in the ecosystem and the effects of climate change on the nitrogen dynamics in the future. In this study, we determined the monthly changes in ammonium nitrogen, nitrate nitrogen, dissolved organic nitrogen (DON), and MBN contents of the topsoil (at depths of 0–20 cm) from April 2016 to March 2017 in the permafrost region on the QTP. The results show that soil NH4+-N and DON contents decreased during the growing season, while soil NO3-N content increased during the growing season and in the middle of the winter. The soil MBN contents increased at the beginning of the growing season and decreased during peak growth period, despite significant variations among the different sites. The soil temperature was positively correlated with soil NO3-N content but it was negatively correlated with the NH4+-N and DON contents. The soil moisture was positively correlated with the soil NO3-N, DON, and MBN contents. The primary factor affecting the seasonal patterns in soil NO3-N and DON contents was soil moisture. Soil moisture and plant growth also affected soil MBN via nutrient competition. The nutrient uptake by plants overwhelmed effect of temperature on the MBN in growing season. These findings improve our understanding of the nitrogen biochemical cycles and their response to future climate change.

131. 题目: Oxidation of soil organic carbon during an anoxic-oxic transition
文章编号: N20072203
期刊: Geoderma
作者: Qian Zhao, Sarrah Dunham-Cheatham, Dinesh Adhikari, Chunmei Chen, Aman Patel, Simon R. Poulson, Daniel Obrist, Paul S.J. Verburg, Xilong Wang, Eric R. Roden, Aaron Thompson, Yu Yang
更新时间: 2020-07-22
摘要:

Redox reactions of iron (Fe) can play an important role in controlling the stability and transformation of organic carbon (OC) in soils. However, there is limited knowledge about the dynamics of Fe and OC in soils during anoxic-oxic transitions, which are common in temperate and tropical biomes. In this study, we investigated the fate and transformation of Fe and OC during a 5-day oxic incubation of four pre-reduced (8 days anoxic) forest soils. Up to 3.7% of total OC in the pre-reduced soils was oxidized to CO2, in conjunction with the oxidation of 31–84% of the extractable Fe(II). OC oxidation in pre-reduced soils was lower than non-reduced control soils, indicating that recently anoxically-incubated soils support lower OC metabolism upon re-oxidation than consistently oxic soils. Oxic OC oxidation was negatively correlated with the fraction of Fe-bound OC and the fraction of short-range-ordered (SRO) Fe oxides. These results suggest that association with Fe oxides—especially SRO Fe oxides—can inhibit the availability of OC for oxidation. However, the difference between the oxidation of OC in pre-reduced soils and consistently oxic controls could not be linked to the moderate changes in the Fe mineral composition during the anoxic-oxic transition, indicating the importance of longer-term OC association with Fe oxides, as well as other processes, in regulating the oxidation of OC during the redox fluctuations. OC association with Fe oxides should be considered during simulations of biogeochemical cycling of OC in soils during the redox fluctuations, for which other processes such as the anoxic transformation of OC and response of the microbial community also need to be incorporated.

132. 题目: Algae removal performance of UV-radiation-enhanced coagulation for two representative algal species
文章编号: N20072202
期刊: Science of the Total Environment
作者: Ruihua Dai, Yiming Xiong, Yingxiao Ma, Tingting Tang
更新时间: 2020-07-22
摘要:

Algal blooms severely impact the ecological environment and human health, as well as drinking water supplies and treatment systems. This study investigated UV-radiation-enhanced aluminum (Al)-based coagulation for the removal of two representative algal species (Microcystis aeruginosa and Cyclotella sp.) which are responsible for most fresh water algal bloom in different seasons. The results demonstrated that the UV-Al process can enhance algae removal, and simultaneously control algal organic matter (AOM) release. Comparing with Microcystis aeruginosa, Cyclotella sp. was more sensitive to UV irradiation and its activity was severely inhibited by 240 s of UV irradiation; intracellular reactive oxygen species (ROS) increased sharply then decreased rapidly, and SEM images showed cell walls exhibited substantial compression. UV irradiation decreased the zeta potential, which might have contributed to algae removal. Approximately 93.5% of Microcystis aeruginosa cells and 91.4% of Cyclotella sp. cells were removed after 240 s of UV irradiation with 0.4 mmol/L Al. The MCs concentrations after Al coagulation were low (<100 ng/L). The DOC of Microcystis aeruginosa and Cyclotella sp. was also lower (1.2 and 1.6 mg/L, respectively) than the national standard level after UV-Al process. This study highlights the practical application of UV irradiation for enhancing algae removal and simultaneously controlling AOM release in water treatment plants, which is a simple and promising technology. This result also indicates that the water treatment parameters should be adjusted according to the algae species present in different seasons, especially for diatom which needs low UV irradiation and Al dosage.

133. 题目: Controlling biofilm retention time in an A-stage high-rate moving bed biofilm reactor for organic carbon redirection
文章编号: N20072201
期刊: Science of the Total Environment
作者: Alessandro di Biase, Maciej S. Kowalski, Tanner R. Devlin, Jan A. Oleszkiewicz
更新时间: 2020-07-22
摘要:

The A-stage of the AB process can minimize carbon oxidation by redirecting carbon to side-stream processes for harvesting carbon as energy and/or bioproduct. The redirection/harvesting of carbon has been studied in systems which utilize suspended biomass cultures. The potential of high-rate moving bed biofilm reactors, however, has not been explored. This study sought to control the biofilm solids retention time in a high-rate moving bed biofilm reactor operated at 17 ± 4 g-bCOD m−2d−1. Biofilm solids retention time was controlled by one of two strategies (i.e., 100% and 60% effective biofilm removal) that targeted several nominal biofilm solids retention times (i.e., 8, 6, 4, and 2 days) by employing different biocarrier replacement times. The results demonstrated that the suspended solids activity could be reduced by decreasing the nominal biofilm solids retention time. Using the 60% biofilm removal strategy, the actual biofilm solids retention time with a nominal biofilm solids retention time of 2 days was 12 h. When utilizing the 100% biofilm removal strategy, an actual biofilm solids retention time of less than 3 h was achieved with a nominal biofilm solids retention time of 2 days. The control reactor, which was a conventional moving bed biofilm reactor with no biocarrier replacement, was estimated to have a biofilm solids retention time of 2 days. Overall, the biofilm removal strategies favored carbon redirection and maximized the biomass yield at 1.1 ± 0.3 g-TSS g-COD−1 removed.

134. 题目: Soil aggregation accounts for the mineral soil organic carbon and nitrogen accrual in broadleaved forests as compared to that of coniferous forests in China: cross‐sites and multiple species comparisons
文章编号: N20072102
期刊: Land Degradation and Development
作者: Chenhui Wei, Qiong Wang, Manli Ren, Zhongxue Pei, Jiali Lu, Huimei Wang, Wenjie Wang
更新时间: 2020-07-21
摘要: Differences in soil organic carbon (SOC) and total nitrogen (TN) between broadleaved and coniferous forests are not well‐defined, hindering the evaluation of the influence of forest‐type on land degradation and development. For these two forest‐types, we determined differences in soil aggregation, SOC, and TN by comparing 202 plots at six sites with 14 common afforestation tree species. Bulk soil was separated to macroaggregates (0.25–2 mm), microaggregates (0.053–0.25 mm), and silt and clay fractions (<0.053 mm). Inter‐site variations were excluded by MANOVA (multiple analysis of variance) and MANCOVA (multiple analysis of covariance). Broadleaved forests exhibited 30–50% higher SOC and TN in bulk soils than that of coniferous forests, and aggregates contributed to 75–77% of the SOC and TN accrual. The high accrual was a result of SOC and TN concentration increases in aggregates (30–50%), macroaggregates fraction increases (50%, with a 14% decrease in the non‐aggregate fractions), aggregates diameter increases (one‐third), and non‐significant differences in C/N. Uncertainty tests showed a low bias (4.2%), and the accrual of SOC and TN in broadleaved forests were larger at sites with less clay and at higher altitude and more precipitation and afforested with more Fraxinus and less poplar. Our results highlight that SOC and TN accrual in broadleaved forests is mainly due to the stronger aggregates protection, which should be fully considered during precise land evaluation and species selection for afforestation. Future studies identifying the mechanisms underlying these changes should consider interactions among leaf functional traits, aggregation‐disaggregation processes, and microbial rhizosphere deposition.

135. 题目: Evidence for brown carbon absorption over the Bay of Bengal during the southwest monsoon season: a possible oceanic source
文章编号: N20072101
期刊: Environmental Science: Processes & Impacts
作者: Poonam Bikkina, Srinivas Bikkina, Kimitaka Kawamura, A. K. Sudheer, G. Mahesh, S. Kuswanth Kumar
更新时间: 2020-07-21
摘要: The near UV-visible light-absorbing organic carbon (OC) of ambient aerosols, referred to here as brown carbon (BrC), significantly influences the atmospheric radiative forcing on both regional and global scales. Here, we documented BrC absorption in the aqueous and methanol extracts of marine aerosols collected over the Bay of Bengal (BoB: September–October 2017) and a city, Visakhapatnam (May–June 2018), in southern India during the southwest monsoon (i.e., a transition period with weak continental impact). The absorption spectra of BrC over the BoB showed several peaks around 300–400 nm and differ from those observed over Visakhapatnam. The absorption coefficient of BrC over the BoB, unlike Visakhapatnam data, does not seem to covary with other chemical proxies of biomass burning (non-sea-salt or nss-K+) and coal combustion (nss-SO42−) in the continental outflows, suggesting a different source of BrC over the BoB. Besides, we observed higher proportions of water-insoluble organic carbon (WIOC/OC: 0.89 ± 0.02) and significant enrichment of Mg2+ over Na+ (i.e., relative to seawater) in BoB aerosols. This result and the backward air mass trajectories both hinted their major source of OC from marine-derived organic matter. In contrast, the absorption spectra of BrC over Visakhapatnam are like those from biomass burning emissions in the Indo-Gangetic Plain. This observation is further supported by the satellite-based fire counts and backward air mass trajectories. Therefore, our study underscores the BrC aerosols from the oceanic sources and southern India, hitherto unknown, and can improve our understanding of the regional climate effects of carbonaceous aerosols if included in models.

136. 题目: Plant productivity and microbial composition drive soil carbon and nitrogen sequestrations following cropland abandonment
文章编号: N20072004
期刊: Science of the Total Environment
作者: Jiwei Li, Miaoyu Li, Lingbo Dong, Kaibo Wang, Yulin Liu, Xuying Hai, Yingjie Pan, Wenwen Lv, Xiaozhen Wang, Zhouping Shangguan, Lei Deng
更新时间: 2020-07-20
摘要:

Understanding the variations in soil organic carbon (SOC) and total nitrogen (STN) stocks in the different ages of abandoned cropland ecosystems of different ages is essential for land use decisions to maximize C sinks or improve ecosystem services. However, knowledge of the dynamics of SOC and STN stocks and their controlling factors after cropland abandonment is limited. Thus, this study investigated the changes in the SOC and STN stocks of loessal soil (Calcaric Regosols) with a chronosequence of 3, 8, 13, 18, 23 and 30 years following cropland abandonment on the Loess Plateau. As a whole, we examined 42 field plots and implemented multivariable linear regression analysis (MLRA) and structural equation modeling (SEM) using 22 influencing variables related to plant, soil and microbial properties to quantify the controls of SOC and STN stocks. The results revealed that SOC and STN stocks significantly increased after cropland abandonment for 30 years, and there were minor decreases in C and N sequestrations in the early restoration stage (<18 years). The SOC and STN changes had significant positive correlations, in which that exhibited STN stocks shifted concurrently with the rate of relative SOC stock changes. The MLRA models demonstrated that the SOC stocks were primarily controlled by aboveground biomass, STN, fungi, and the ratio of fungi to bacteria, while STN stocks were mainly driven by root biomass, above-ground biomass, STN, fungi and the ratio of fungi to bacteria after cropland abandonment. The SEM models further demonstrated that plant productivity not only directly determined the variations in SOC and STN stocks but also changed the microbial community following post-cropland restoration. These results suggest that long-term (>18 years) cropland abandonment can be a successful approach for reinstating SOC and STN stocks, while plants and microbes together mediate microbial C and N stocks during vegetation succession in a semiarid region.

137. 题目: Stronger network connectivity with lower diversity of soil fungal community was presented in coastal marshes after sixteen years of freshwater restoration
文章编号: N20072003
期刊: Science of the Total Environment
作者: Rong Xiao, Yutong Guo, Mingxiang Zhang, Wenbin Pan, Jian Jim Wang
更新时间: 2020-07-20
摘要:

Freshwater input for salt marsh restoration in the Yellow River Delta induced Phragmites australis expansion and thus may cause shifts of soil fungi from halophilic to desalination-adapted species for increased litter decomposition. In this study, soil fungal communities of restored and natural salt marshes were determined to reveal further details of shift in soil fungal community and its probable prediction for salt marsh restoration. Our results showed a stronger network within Ascomycota (e.g. Sordariales, Aspergillus, Hypocreales and Cladosporium herbarum) in restored marshes, but with a lower diversity of halophilic taxa (e.g. Chytridiomycota and Nematoda) in comparison with natural salt marshes. Contrarily, the occurrence of Chytridiomycota, Ichthyosporea and Discicristoidea in the soil fungal networks of the natural salt marsh emphasized the importance of salt tolerant species at the land-sea transition zone. The Sordariales was dominant and had a strong correlation with other fungal species and aggregate associated soil organic carbon (SOC), which probably contributed to SOC accumulation in restored marshes. But the reduced halophilic species specific to salt marsh elucidated that the formation of monospecific stands of P. australis along with the freshwater input induced desalination to the saline habitats changed the native patterns of vegetation and soil organisms. As the buffer between terrestrial and marine systems, a single habitat type such as dense monocultures of P. australis must be avoided and diverse saltmarsh habitats across a salinity gradient should be reserved. In this way, the diversity and specificity of coastal halophytes and related microorganisms could be maintained and thus might confer benefits in balancing various functions of the salt marsh ecosystem and preserving the system's elasticity and resistance to stress.

138. 题目: Antibiotic resistance genes in sediments of the Yangtze Estuary: From 2007 to 2019
文章编号: N20072002
期刊: Science of the Total Environment
作者: Xing-pan Guo, Sai Zhao, Yu-ru Chen, Jing Yang, Li-jun Hou, Min Liu, Yi Yang
更新时间: 2020-07-20
摘要:

To better understand the occurrence and succession of antibiotic resistance genes (ARGs) in the environment, the investigation of ARGs in sediment for a long time scale is urgently needed. In this study, sediment samples were taken in the Yangtze Estuarine area from 2007 to 2019, and the interannual variations in ARGs and their possible physicochemical and socioeconomic influencing factors were analyzed. The results showed that the abundance of ARGs, including sul1, sul2, tetM, tetW, aac(6′)-Ib and qnrS, was higher in recent years (from 2015 to 2019) than that in earlier years (from 2007 to 2011), and heavier ARG pollution was found in Wusongkou (WSK) samples than in Liuhekou (LHK) samples. According to the redundancy discriminant analysis (RDA) and correlation analysis, the antibiotics (especially individual antibiotic categories, including oxytetracycline, doxycycline hyclate and norfloxacin), metals and a metal resistance gene (zntA) and total organic carbon (TOC) showed significant correlations to ARGs. In addition, antibiotics, metals, TOC and ARGs were also significantly correlated with several socioeconomic indices. Furthermore, the extended STIRPAT model analysis revealed that the second industry product and the first industry product were the major socioeconomic driver factors for the ARG distribution at WSK and LHK, respectively. Overall, with socioeconomic development, antibiotics, metals, TOC and ARGs increased in sediment. In addition, antibiotics, metals and TOC may participate in the regulation of the occurrence and distribution of ARGs in the Yangtze Estuary for the long time scale.

139. 题目: Application of Fourier transform ion cyclotron resonance mass spectrometry to characterize natural organic matter
文章编号: N20072001
期刊: Chemosphere
作者: Xiaoxiao Zhang, Jiarui Han, Xiangru Zhang, Jimin Shen, Zhonglin Chen, Wei Chu, Jing Kang, Shengxin Zhao, Yaoyu Zhou
更新时间: 2020-07-20
摘要:

Advances in the ultra-high-resolution mass spectroscopy lead to a deep insight into the molecular characterization of natural organic matter (NOM). Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) has been used as one of the most powerful tools to decipher NOM molecules. In FTICR-MS analysis, the matrix effects caused by the co-occurring inorganic substances in water samples greatly affect the ionization of NOM molecules. The inherent complexity of NOM may hinder its component classification and formula assignment. In this study, basic principles and recent advances for sample separation and purification approaches, ionization methods, and the evolutions in formula assignment and data exploitation of the FTICR-MS analysis were reviewed. The complementary characterization methods for FTICR-MS were also reviewed. By coupling with other developed/developing characterization methods, the statistical confidence for inferring the NOM compositions by FTICR-MS was greatly improved. Despite that the refined separation procedures and advanced data processing methods for NOM molecules have been exploited, the big challenge for interpreting NOM molecules is to give the basic structures of them. Online share of the FTICR-MS data, further optimizing the FTICR-MS technique, and coupling this technique with more characterization methods would be beneficial to improving the understanding of the composition and property of NOM.

140. 题目: Effect of lychee biochar on the remediation of heavy metal-contaminated soil using sunflower: A field experiment
文章编号: N20071914
期刊: Environmental Research
作者: Liu Jun, Huang Wei, Mo Aili, Ni Juan, Xie Hongyan, Hu Jingsong, Zhu Yunhua, Peng Cuiying
更新时间: 2020-07-19
摘要:

Heavy metal contamination of soils is a serious issue with various consequences in Hunan Province. Here, we aimed to determine the effect and action mechanisms of lychee biochar on the remediation of Pb, Cd, As, and Zn from soil using sunflower (Helianthus annuus). Different amounts of lychee biochar (2.5, 5, and 10%) were added to heavy metal-contaminated soil in the Shuikoushan mining area, Hunan Province. The effects of biochar on the biomass of sunflower plants, and the accumulation and distribution of Pb, Cd, As, and Zn in sunflower plants, and changes in Pb, Cd, As, and Zn concentrations in the rhizosphere soil were studied. The application of biochar stimulated the growth of the sunflower plants, with the maximum biomass recorded in the 5% biochar treatment; however, above this level, biochar inhibited plant growth. Pb, Cd, As, and Zn in sunflower plants were redistributed with biochar addition. The concentration of Pb, Cd, As, and Zn in the leaves and receptacles of sunflower plants increased with biochar application, but their concentration in the roots, stems, and seeds significantly decreased compared with the control. The total amount of accumulated Pb, Cd, and As in sunflower plants increased by 22.9–58.9%, 15.8–42.3%, and 67.9–110%, respectively, compared with that in the control. In the biochar treatments, the total amount of accumulated Zn in sunflowers decreased by 13.8–37.2%, compared with that in the control. The accumulated Pb, Cd, and As in sunflower plants have an antagonistic effect on Zn required by sunflowers. The sunflower plants significantly reduced the concentration of Pb, Cd, As, and Zn in contaminated soil (P < 0.05), which decreased by 12.4, 11.0, 4.35, and 8.17%, respectively, compared with that before planting sunflower. The addition of biochar in heavy metal-contaminated soil significantly enhanced the heavy metal-remediation effect of sunflower. Compared with the control (0% biochar), 10% biochar application decreased the Pb, Cd, As, and Zn concentrations in the rhizosphere of sunflower plants, by 40.6, 31.6, 35.4, and 30.8%, respectively. In conclusion, lychee biochar enhanced the remediation of heavy metals in contaminated soil.

 共 8434 条记录  本页 20 条  本页从 121-140 条  7/422页  首页 上一页  2 3 4 5 6 7 8 9 10 11 12  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。