论文检索

主页 | 软件工具 | 课题库 | 公众号
:



总访问量:660856

总访客量:27976

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

241. 题目: Recycling biochar derived from tannery liming sludge for chromium adsorption in static and dynamic conditions
文章编号: N21100719
期刊: Environmental Technology & Innovation
作者: Sofia Payel, Md. Abul Hashem, Md. Anik Hasan
更新时间: 2021-10-07
摘要:

In tannery industry, unhairing and liming (termed as liming) are indispensable but it is a very polluting part of process when producing quality leather. Expelled wastewater from liming generates significant amounts of liming sludge. In this study, efficacies of liming sludge biochar derived for adsorption of chromium from tannery wastewater are described. The biochar was characterized by FTIR, SEM, EDX, and BET technologies, and pHzpc. Surface area and responsible functional groups of biochar were as follows: 9.2 m2/g and C-H, C-N, C-O, C=C, N-H, S=O, and O-H. EDX analysis revealed chromium adsorption and SEM images led to changes in surface morphology. pHzpc for dry liming sludge and biochar were 4.1 and 6.1, respectively. Batch adsorption was verified by assorted parameters including biochar dose, shaking speed, contact time, and dilution factor. Column study results confirm the highest chromium adsorption efficiencies of 408.12 and 533.41 mg/g for 3 cm and 5 cm bed height, respectively. Regression coefficient suggested that adsorption obeys the Freundlich isotherm and pseudo-second order kinetics in batch mode, while it follows the Yoon-Nelson model in column mode. The physicochemical parameters of tannery wastewater prior and post-adsorption revealed good removal efficiencies for chloride content (Cl), chemical oxygen demand (COD), and biochemical oxygen demand (BOD) were, respectively, 50.5%, 80.1%, and 85.5%. Desorption process recovers 69.37 mg/g Cr from adsorbed biochar which could be reused in the tanning process. Consequently, an innovative state-of-the-art tannery liming sludge biochar can satisfactorily use in tannery wastewater treatment by following wealth-from-waste principle.

242. 题目: Stability of biochar in mineral soils: Assessment methods, influencing factors and potential problems
文章编号: N21100718
期刊: Science of The Total Environment
作者: Hao Wang, Qiong Nan, Muhammad Waqas, Weixiang Wu
更新时间: 2021-10-07
摘要: Amendment of biochar into mineral soils has been reported a promising strategy for carbon sequestration and greenhouse gas mitigation due to its high stability. Currently, most studies on the stability of biochar are mainly focused on the assessment methods and influencing factors. The assessment methods include qualitative evaluation of physical and chemical properties, and utilization of kinetic mineralization models on the basis of laboratory incubation. As a result, these assessment methods are difficult to accurately reflect the real impact of the interaction between biochar and environmental factors. This article reviews the existing assessment methods, influencing factors, and the impact of environmental aging on the stability of biochar. It is found that under the influence of environmental factors, existing assessment methods are likely to overestimate the stability of biochar in mineral soils. Therefore, more emphases should be laid on the analyses of the deficiencies in the existing assessment methods on the stability of biochar in the consideration of practical applications. Long-term field experiment is strongly recommended to establish a more accurate assessment model on biochar stability for the evaluation of its carbon sequestration potential in mineral soils.

243. 题目: A techno-economic analysis of biochar production and the bioeconomy for orchard biomass
文章编号: N21100717
期刊: Waste Management
作者: Maryam Nematian, Catherine Keske, John N Ng'ombe
更新时间: 2021-10-07
摘要:

It is well established that the global practice of burning crop residues, such as orchard biomass, harms human health and the environment. A bioeconomy for orchard biomass may reduce open burning, facilitate the recovery of nutrients that improve soil health, and boost economic growth. We present a techno-economic analysis for converting orchard waste into biochar, a charcoal-like substance that shows promise for improving soil health, but that is considered an experimental product with emerging efficacy and limited market demand. We impute values derived from a cost analysis of biochar production in California’s Central Valley into a regional economic input-output model to demonstrate economic growth and a bioeconomy for biochar made with orchard waste. Results from a stochastic Monte Carlo simulation show a probable range of biochar production costs between $448.78 and $1,846.96 (USD) Mg−1, with 90% probability that costs will range between $571 and $1,455 Mg−1. A sensitivity analysis shows that production costs are most responsive to biochar production rates. A modifiable Excel-based biochar enterprise budget that includes fixed and variable biochar production costs is provided as Supplementary Material. The regional economic analysis demonstrates positive economic growth as defined by job creation, labor compensation, value-added product, and gross output. Stochastic cost estimates and net positive regional economic impacts support economic feasibility of a circular bioeconomy for waste orchard biomass when coupled with governmental policy initiatives. Results may contribute to developing a circular bioeconomy for biochar and orchard biomass in the study region and elsewhere in the world.

244. 题目: Biochar nanoparticles with different pyrolysis temperatures mediate cadmium transport in water-saturated soils: Effects of ionic strength and humic acid
文章编号: N21100716
期刊: Science of The Total Environment
作者: Ming Chen, Dengjun Wang, Xiaoyun Xu, Yue Zhang, Xiangyang Gui, Bingqing Song, Nan Xu
更新时间: 2021-10-07
摘要: Biochar is advocated as an environment-friendly and cost-effective material for removing both heavy metals and organic contaminants in soil remediation. However, our understandings on the cotransport potential of contaminants with the nanoscale biochar downward along soil profiles (e.g., potential environmental risks towards groundwater) remain largely unknown. This study investigated the effects of wheat straw-derived biochar nanoparticles pyrolyzed at 350 °C and 500 °C (BNP350 and BNP500) on the transport of cadmium (Cd(II)) in water-saturated soil packed columns. Different ionic strengths (ISs) without/with humic acid (HA) were tested to mimic the scenarios during soil remediation. BNPs could act as a vehicle mediating Cd(II) transport in soils. At a low IS (1.0 mM KCl), compared to the limited transport of individual Cd(II), BNP500 enhanced (69 times) Cd(II) transport (Cd(II) mass recovery (M) = 7.59%) in soils, which was greater than that by BNP350 (54 times, M = 5.92%), likely due to the higher adsorption of Cd(II) onto BNP500. HA further increased the Cd(II) transport by BNPs (M = 8.40% for BNP350 and M = 11.95% for BNP500), which was mainly due to the increased mobility of BNPs carrying more absorbed Cd(II). In contrast, at a high IS (10 mM KCl), BNP500 dramatically inhibited the transport of Cd(II) (M = 12.9%), decreasing by about 61.6%, compared to the BNPs absence (M = 33.6%). This is because a large amount of BNP500-Cd(II) was retained in soils at a high IS. This inhibition effect of Cd(II) transport by BNPs was reinforced with the presence of HA. Our findings suggest that the pyrolysis temperature of biochar should be carefully considered when applying biochar for in-situ remediation of soils contaminated by heavy metals such as Cd(II) under various organic matter and IS conditions.

245. 题目: Molecular and optical characterization reveals the preservation and sulfurization of chemically diverse porewater dissolved organic matter in oligohaline and brackish Chesapeake Bay sediments
文章编号: N21100715
期刊: Organic Geochemistry
作者: Leanne C Powers, Laura Lapham, Sairah Y Malkin, Andrew Heyes, Philippe Schmitt-Kopplin, Michael Gonsior
更新时间: 2021-10-07
摘要: In this study, we conducted a detailed analysis of porewater downcore chemical properties and porewater dissolved organic matter (PDOM) composition using elemental C, N and S analysis, fluorescence spectroscopy, and ultrahigh resolution mass spectrometry (FT-ICR MS) at two contrasting sites in Chesapeake Bay. The sites, situated in the oligohaline upper bay and in the seasonally hypoxic mesohaline mid bay, receive fundamentally different detrital inputs predominantly from allochthonous and autochthonous sources, respectively. Unsurprisingly, we observed greater molecular oxygenation and degree of aromaticity in downcore PDOM profiles from the upper bay. At the mid bay station, PDOM composition was more indicative of non-aromatic algal-derived material. Unexpectedly, this autochthonous PDOM had lower C:S ratios. Hence, algal-derived organic matter appeared to be readily sulfurized, which was confirmed by quantification of dissolved organic sulfur as well as by qualitative interpretation of FT-ICR MS data. This finding suggests addition reactions of hydrogen sulfide to double bonds in unsaturated, but non-aromatic, organic molecules in autochthonous PDOM. Intriguingly, we also observed increases in humic-like fluorescence and dissolved organic carbon (DOC) concentrations in downcore PDOM profiles from both sites. Given the differences in molecular composition between sites, these results show that humic-like fluorescence can arise from different sources and biogeochemical processes. In the upper bay, we infer that these fluorescence signals reflect solubilization of terrestrially derived organic matter with a high aromatic and polyphenolic composition. By contrast, in the mid bay, these fluorescence peaks correlated negatively with hydrogen sulfide and are more likely linked to bacterial sulfate reduction.

246. 题目: Long-term grass mulching waste recycling and evaluation activation of dissolved organic carbon
文章编号: N21100714
期刊: Chemosphere
作者: Jianfeng Yang, Yumin Duan, Xiaoping Wu, Yuli Tian, Long Yang, Yueyang Zhang, Zhenzhong Liu, Mukesh Kumar Awasthi, Huike Li
更新时间: 2021-10-07
摘要: This study aimed to clarify that long-term leguminous grass mulching (crown vetch (CV) and white clover (WC)) and gramineous grass (orchardgrass (OG)) drive the distribution of soil aggregates and are associated with dissolved organic matter (DOM) components. Excitation emission spectroscopy and parallel factor analysis (EEM-PARAFAC) were used to evaluate the influence of different grass mulches among aggregates. The results indicated that legumes had a more significant impact on the distribution of aggregates and DOM content than gramineae grass mulching. Leguminous grass mulching significantly increased the proportion of macroaggregates >250 μm (74.65%–83.50%) and aggregates associated with dissolved organic carbon (DOC), especially in microaggregates <250 μm (172.27 mg kg−1 to 391.55 mg kg−1). In addition, leguminous grass mulching (CV and WC) contributed more to the increase in soil total nitrogen (TN) and three identified fluorescent components (UVC humic-like, UVA humic-like and protein-like). The component of UVC humic-like relative abundance decreased (48.66%–36.57%), and the protein-like component increased (21.88%–36.50%) as the aggregate size decreased, but the DOM three compositions did not change. The DOM of macroaggregates had higher aromaticity and lower molecular weight than microaggregates, and the highest abundance of UVC humic-like component (54.52%) was found in the gramineous (OG) large macroaggregates, while the higher abundance of protein-like components (31.07%–36.50%) occurs in leguminous mulching (CV and WC) microaggregates. The results contribute to a further understanding of the dynamic process by which grass mulching mediates aggregate formation and DOM component transformation in semiarid apple orchards under grass waste management.

247. 题目: Biological ion exchange as an alternative to biological activated carbon for natural organic matter removal: Impact of temperature and empty bed contact time (EBCT)
文章编号: N21100713
期刊: Chemosphere
作者: Zhen Liu, Emily C Mills, Madjid Mohseni, Benoit Barbeau, Pierre R Bérubé
更新时间: 2021-10-07
摘要: Biofiltration is a widely used process in drinking water treatment plants to remove natural organic matter (NOM). A novel biofiltration process using ion exchange resins as supporting media (i.e., biological ion exchange or BIEX) has been demonstrated to provide a superior performance compared to conventional biological activated carbon (BAC). In order to optimize the performance of BIEX filters, the impact of temperature and empty bed contact time (EBCT) on NOM removal was systematically studied. In the present study, bench-scale BIEX filters were set up in parallel with BAC filters and operated at different temperatures (i.e., 4 °C, 10 °C and 20 °C) and EBCTs (i.e., 7.5 min, 15 min and 30 min). Higher average dissolved organic carbon (DOC) removal was achieved in BIEX filters (73 ± 6%) than BAC filters (22 ± 9%) at the steady state with an EBCT of 30 min. Higher temperatures improved NOM removal in both BAC and BIEX filters, with the impact being greater at lower EBCTs (i.e., 7.5 min and 15 min). Higher EBCTs could also improve NOM removal, with the impact being greater at lower temperatures (i.e., 4 °C and 10 °C). DOC removal for BIEX and BAC filters can be modeled with a first-order kinetic model (R2 = 0.93–0.99). BAC had a higher temperature activity coefficient than BIEX (1.0675 vs. 1.0429), indicating that temperature has a greater impact on BAC filtration than BIEX filtration. Overall, temperature and EBCT must be considered simultaneously for biofilters to efficiently remove NOM.

248. 题目: FOREST LITTER CONSTRAINTS ON THE PATHWAYS CONTROLLING SOIL ORGANIC MATTER FORMATION
文章编号: N21100712
期刊: Soil Biology and Biochemistry
作者: Luís F.J. Almeida, Ivan F Souza, Luís C.C. Hurtarte, Pedro Paulo Teixeira, Thiago M Inagaki, Ivo R Silva, Carsten W Mueller
更新时间: 2021-10-07
摘要: The connection between litter chemistry and the pathways controlling soil organic matter (SOM) formation and decay in forest ecosystems remains poorly understood, particularly in tropical soils. We addressed this question by incubating samples of a Ferralsol for 200 days with typical forest litter (leaves, twigs, bark, and roots) obtained from 13C-enriched Eucalyptus seedlings. Throughout the incubation, we monitored 13C/12C–CO2 evolved from the soil to quantify the microbial respiration of the 13C-labeled fresh plant litter and of the native SOM. Afterwards, we used density fractionation to obtain particulate organic matter (POM) with density <1.8 g cm–3, and the soil material remaining was wet-sieved to obtain SOM with particle-size >53 μm and mineral-associated SOM (MAOM, with particle-size <53 μm). We used solid-state 13C-CPMAS-NMR spectroscopy to assess the molecular composition of plant material and SOM fractions and quantified microbial amino sugars in bulk soil using gas chromatography. Our 13C/12C–CO2 results indicate that leaves, twigs, and bark (aboveground litter) were respired at higher rates but led to lower degradation of native SOM as compared to root tissues. On average, aboveground litter promoted net C gains in both POM and MAOM, whereas root litter only led to net C gains in POM. Overall, SOM formation via microbial incorporation of aboveground litter through in vivo pathways appears to be more efficient and causes less degradation of native MAOM than roots. Moreover, a reduction in microbial amino sugars in bulk soils suggests that in vivo pathways also favored the formation of POM, which had more microbial-derived protein than forest litter. Therefore, the connection between litter chemistry and the pathways controlling SOM formation in tropical forest ecosystems must be included in a framework that also considers the mineralization of native SOM and the vertical separation of aboveground and belowground C inputs to soils.

249. 题目: Factors shaping soil organic carbon stocks in grass covered orchards across China: A meta-analysis
文章编号: N21100711
期刊: Science of The Total Environment
作者: Yangzhou Xiang, Yuan Li, Ying Liu, Siyu Zhang, Xuejiao Yue, Bin Yao, Jianming Xue, Wenqiang Lv, Leiyi Zhang, Xiuyue Xu, Yonghua Li, Song Li
更新时间: 2021-10-07
摘要: Orchard grass coverage has been widely adopted to increase fruit yield by improving soil fertility. However, the impact of the environment on the changes in soil organic carbon (SOC) stocks consecutive to orchard grass coverage remain poorly quantified at a large scale. The present study aimed to examine the responses of SOC stocks to grass coverage at a soil depth of 0–30 cm in orchards compared to clean tillage. A total of 342 observations across China from 139 peer-reviewed publications were subjected to meta-analysis. Aggregated boosted tree analysis was performed, evaluating the determinants of SOC stocks, such as plant traits (e.g., fruit tree type, grass type, orchard age, and grass age), edaphic variables (e.g., initial SOC and nitrogen concentration, soil pH, and soil clay content), climatic factors (e.g., mean annual precipitation (MAP) and mean annual temperature (MAT)), and management practices (e.g., grass source, grass growing mode, fertilization, grass mowing, placement of mowed residues, and irrigation). On average, orchard grass coverage significantly enhanced SOC stocks by 21.47% (percentage change) compared to clean tillage. Biotic and abiotic factors influenced this increase in SOC stocks following grass coverage in orchards to different extents. Grass age and soil clay content were the main determinants driving the variation in the SOC stocks following grass coverage in orchards. Thus, we propose an efficient way to optimize C sequestration in grass covered orchards, regarding plant traits, climatic factors, edaphic variables, and management practices. Longer than 12 months of surface grass coverage with cultivated grass species in mature deciduous fruit orchards (≥5 years) efficiently increased SOC stocks. This is particularly the case for acidic (pH < 6.5) soils with low C content (SOM < 15 g kg−1) in areas with suitable rainfall and temperature conditions (MAP ≥ 400 mm, MAT ≥ 10 °C). Collectively, this meta-analysis identified orchard grass coverage as a promising practice for significantly increasing SOC stocks at 0–30 cm across large geospatial locations in China.

250. 题目: Effects of microplastics on soil carbon dioxide emissions and the microbial functional genes involved in organic carbon decomposition in agricultural soil
文章编号: N21100710
期刊: Science of The Total Environment
作者: Yanxia Zhang, Xing Li, Mao Xiao, Ziyi Feng, Yongxiang Yu, Huaiying Yao
更新时间: 2021-10-07
摘要: The accumulation of microplastics (MPs) in agricultural fields can not only disguise soil organic carbon (SOC) storage but also affect the production of carbon dioxide (CO2) by microbial decomposition. However, little is known about the impact of this emerging pollutant on soil CO2 emissions and the functional genes related to SOC degradation. In the present study, a short-term (30-day) microcosm experiment was performed to investigate the effects of virgin and aged low-density polyethylene (LDPE) MPs on soil CO2 emissions. We also measured functional gene abundances related to starch (sga), hemicellulose (abfA, manB and xylA), cellulose (cex) and lignin (lig and mnp) degradation through a high-throughput quantitative-PCR-based chip. Compared with the soils without MPs, low doses (0.01% and 0.1%) of both virgin and aged MPs had negligible effects on SOC decomposition, whereas a high dose (1.0%) of these two MPs significantly (p < 0.05) accelerated the production of CO2 in soils by 15–17%, showing a dose-dependent effect. The presence of MPs did not significantly affect soil dissolved organic carbon or microbial biomass carbon. A higher metabolic quotient at 1.0% MP concentration indicated that the microbes were stressed and needed more substrates and energy during their metabolic process, which could likely explain the increase in CO2 emission induced by this dose of MPs. Exposure to virgin MPs significantly reduced the functional genes related to hemicellulose (abfA and manB) degradation, whereas increasing the aged MPs concentrations significantly decreased the abundances of functional genes encoding starch (sga), hemicellulose (abfA, manB and xylA), and cellulose (cex) hydrolysis. Overall, we conclude that the low dose (<0.1%) of MPs in the soils has a negligible effect on the production of CO2, but this factor should be considered in evaluating the global C budget in future research as this contaminant reaches a certain threshold (1.0%).

251. 题目: A novel organic carbon accumulation mechanism in croplands in the Yellow River Delta, China
文章编号: N21100709
期刊: Science of The Total Environment
作者: Junyu Dong, Wei Wang, Di Zhao, Chao Zhang, Jiaohui Fang, Lifei Wang, Qingzhu Zhang, Jian Liu
更新时间: 2021-10-07
摘要: The trends and mechanisms of organic carbon changes in coastal delta croplands are not yet clear due to the complexity physicochemical processes in soil. In this study, combing powder x-ray diffraction (XRD), microbial analysis, and density functional theory in quantum mechanics, we proposed a novel mechanism underlying OC accumulation. We investigated changes of three kinds of organic carbon (OC)-dissolved organic carbon (DOC), light fraction organic carbon (LFOC), and heavy fraction organic carbon (HFOC) in the Yellow River Delta croplands. We found that HFOC, dominant in coastal delta cropland soil, formed at different ages and its density increased with increasing reclamation time. Yet, DOC and LFOC had no significant increase or decrease tendency. Moreover, in coastal delta croplands, HFOC accumulation might be a complex progress, including the loss of indigenous OC and the accumulation of newly input OC. Based on these results, we proposed that although root exudative DOC (organic acids) could cause the indigenous OC loss by forming a specific microbial community, it still was a source of HFOC and promoted the OC accumulation. More importantly, based on density functional theory, we verified that these root exudative organic acids could adsorb on SiO2 together with crystalline Fe oxides (Fec) to form aggregates. The finding could explain the phenomenon that the XRD results showed samples were compounds of SiO2, Fec, and OC and the accumulation of HFOC in coastal delta croplands. By revealing a new OC accumulation mechanism in coastal delta croplands, this study provides novel insights into the mechanism of OC dynamics in coastal delta croplands and the global carbon budget.

252. 题目: Can biochar and hydrochar be used as sustainable catalyst for persulfate activation?
文章编号: N21100708
期刊: Chemosphere
作者: Mohamed Faisal Gasim, Jun-Wei Lim, Siew-Chun Low, Kun-Yi Andrew Lin, Wen-Da Oh
更新时间: 2021-10-07
摘要: Over the past decade, there has been a surge of interest in using char (hydrochar or biochar) derived from biomass as persulfate (PS, either peroxymonosulfate or peroxydisulfate) activator for anthropogenic pollutants removal. While extensive investigation showed that char could be used as a PS activator, its sustainability over prolonged application is equivocal. This review provides an assessment of the knowledge gap related to the sustainability of char as a PS activator. The desirable char properties for PS activation are identified, include the high specific surface area and favorable surface chemistry. Various synthesis strategies to obtain the desirable properties during biomass pre-treatment, hydrochar and biochar synthesis, and char post-treatment are discussed. Thereafter, factors related to the sustainability of employing char as a PS activator for anthropogenic pollutants removal are critically evaluated. Among the critical factors include performance uncertainty, competing adsorption process, char stability during PS activation, biomass precursor variation, scalability, and toxic components in char. Finally, some potential research directions are provided. Fulfilling the sustainability factors will provide opportunity to employ char as an economical and efficient catalyst for sustainable environmental remediation.

253. 题目: Dissolved organic compounds with synchronous dynamics share chemical properties and origin
文章编号: N21100705
期刊: Limnology and Oceanography
作者: Julian Merder, Heidelinde Röder, Thorsten Dittmar, Ulrike Feudel, Jan A Freund, Gunnar Gerdts, Alexandra Kraberg, Jutta Niggemann
更新时间: 2021-10-07
摘要: The temporal dynamics of dissolved organic matter (DOM) are inherently linked with the functioning of aquatic ecosystems. Because DOM represents a complex mixture of millions of different compounds, the statistical analysis of DOM dynamics poses a huge challenge. Here, we present a statistical approach based on hierarchical clustering of time series that groups DOM compounds with synchronous dynamics. We applied this approach to time series of Fourier-transform ion cyclotron resonance mass spectrometry data of DOM sampled over a period of 26 months near Helgoland, an island in the Southern North Sea. We identified three DOM clusters, which represented a total of 1392 different molecular formulae and showed distinct chemical properties and noticeably compound matches within the PubChem database. Correlations of the three DOM clusters with abundance data of prokaryote and phytoplankton species and with environmental parameters provided consistent indications on the potential origin of the clustered compounds. The first cluster integrated terrestrial DOM originating from riverine discharge reaching Helgoland waters. The second cluster was attributed to DOM related to phytoplankton and microbial activity, whereas the third cluster was interpreted as representing the marine refractory DOM background. Accordingly, while further partitioning divided each of the first two clusters into five sub-clusters with distinct temporal dynamics and molecular characteristics, the third cluster persisted as a stable feature. Applying a purely mathematical approach, we thus confirmed the differential dynamics of individual DOM compounds and compound groups and showed that temporal dynamics of dissolved molecules are linked to their origin and transformation history.

254. 题目: Inhibitory Mechanisms of Humic Substances and Polyacrylic Acid during the Initial Stage of Polycation-Induced Flocculation
文章编号: N21100705
期刊: Journal of Environmental Chemical Engineering
作者: Voon Huey Lim, Yuji Yamashita, Kazuyoshi Ogawa, Yasuhisa Adachi
更新时间: 2021-10-07
摘要: Although natural organic matter (NOM) is known to reduce the efficiency of polycationic flocculants used for solid-liquid separation in water treatment processes, mechanisms underlying this inhibitory effect are not yet fully understood. In this study, the inhibitory effects of naturally occurring humic substances and a synthetic polyelectrolyte (as a comparison), polyacrylic acid (PAA), on the initial stage of colloidal flocculation induced by the addition of a cationic linear polyelectrolyte are investigated under a standardized mixing flow condition. Flocculation enhancement is hindered by all the tested polyanions, while electrophoretic mobility experiments reveal that the polyanions affect the isoelectric point of particles. At the same polycation to polyanion charge ratio, the degree of inhibition decreases in the order PAA > Suwannee River humic acid > Suwannee River fulvic acid, corresponding to their affinity toward the polycations and particles. We propose that the inhibitory mechanism is mainly driven by the electrostatic attractions between the flocculant and polyanions, and this mechanism involves three stages. The influence of polyanion affinity on the complexation with polycations is also discussed. The insights gained in this study can be useful in predicting the flocculation behavior of suspended solids co-existing with NOM in natural environments when flocculants are added.

255. 题目: Effects of hydrological environment on litter carbon input into the surface soil organic carbon pool in the Dongting Lake floodplain
文章编号: N21100704
期刊: CATENA
作者: Lianlian Zhu, Zhengmiao Deng, Yonghong Xie, Chengyi Zhang, Xiaorong Chen, Xu Li, Feng Li, Xinsheng Chen, Yeai Zou, Wei Wang
更新时间: 2021-10-07
摘要: Litter carbon is the main source of the surface soil organic carbon pool (S-SOCP). However, the impact of changes in the hydrological environment of natural wetlands on litter input to S-SOCP remains unclear. In the present study, the effects of hydrological changes (soil water content [SWC] and days of flooding [DF]) on the litter decomposition process and S-SOCP were investigated from January 2018 to November 2019 in the Dongting Lake floodplain of China. Furthermore, the contribution of litter to the S-SOCP in Carex meadow and Reed wetland were calculated. The results showed that a large part of litter (approximately 50%–70%) decomposed annually, especially during the flooding season. Litter contributed 283.68 g C m−2 a–1 to the S-SOCP in the Carex meadow and 275.24 g C m−2 a–1 to the Reed wetland. In the Carex meadow and Reed wetland, the belowground litter contribution was higher than the aboveground litter during the non-flooding season. In contrast, during the flooding season, the aboveground litter contribution in the Carex meadow is higher, whereas the belowground litter dominates in the Reed wetland. The SWC indicated a positive correlation with soil organic carbon (SOC) and a negative correlation with the microbial biomass carbon (MBC) and dissolved organic carbon (DOC) in the Carex meadow. However, SWC shows a negative correlation with SOC and a positive correlation with MBC in the Reed wetland during the non-flooding season. During the flooding season, the variation of DOC during the flooding season (ΔDOC) is positively correlated with DF in the Carex meadow and Reed wetland. SWC and DF are the main drivers of litter decomposition into the S-SOCP in non-flooding and flooding seasons, respectively. Therefore, the construction of microhabitat with prolonged flooding and relatively higher soil water content are essential ways to improve the carbon sequestration potential in floodplains.

256. 题目: Response of soil organic matter to cover cropping in water-limited environments
文章编号: N21100704
期刊: Geoderma
作者: Vesh R Thapa, Rajan Ghimire, Dawn VanLeeuwen, Verónica Acosta-Martínez, Manoj Shukla
更新时间: 2021-10-07
摘要: Cover crops are promoted to improve soil health and soil carbon (C) sequestration in agroecosystems, yet responses of various soil organic carbon (SOC) and nitrogen (N) components to cover cropping have not been quantified for water-limited environments. This study evaluated the response of SOC and N components to different cover crops and mixtures in limited irrigation winter wheat (Triticum aestivum L.)-sorghum (Sorghum bicolor L. Moench)-fallow rotation. Cover cropping treatments included pea (Pisum sativum L.), oats (Avena sativa L.), and canola (Brassica napus L.); mixtures of pea + oats (POmix), pea + canola (PCmix), pea + oats + canola (POCmix), and a six-species mixture (SSmix) of pea + oats + canola + hairy vetch (Vicia villosa Roth) + forage radish (Raphanus sativus L.) + barley (Hordeum vulgare L.); and a fallow. Cover crop treatments were arranged in a randomized complete block design within each phase of the crop rotation. Soil samples were collected in the summer of 2019 and 2020 from the 0–15 cm depth of study plots established in fall 2015 and analyzed for various soil organic matter (SOM) components. Soil inorganic N was 7–36% lower with cover crops than fallow. The PCmix had 48–73% greater 24-h-carbon dioxide-carbon (CO2-C) than fallow, canola, and SSmix at termination time. Thirty-six days after termination, particulate organic carbon (OC) content was 61–69% higher with pea, SSmix, and POCmix than fallow. The SOC content was 9.3–22% greater with oats than pea, canola, POmix, and SSmix. Similarly, total N content with oats was 10% and 22% higher than with SSmix and canola, respectively. The increase in SOC and total N were primarily observed in intermediate-size aggregates (250 μm–2 mm and 53–250 μm). However, the minimum data set of soil health included SOC, soil pH, labile organic nitrogen (LON), mineral-associated organic nitrogen (MAON), and microbial biomass carbon (MBC). While this study showed a diverse response of SOC and N components to various cover crop treatments, oats and their mixture as cover crops had greater SOC and total N than other cover crops. Cover cropping could improve soil health in crop-fallow rotations in water-limited environments.

257. 题目: Characteristics of phytolith-occluded organic carbon sequestration in typical plant communities in the Songnen grassland, China
文章编号: N21100703
期刊: Ecological Engineering
作者: Niankang Chen, Lixiang Zhong, Dongmei Jie, Jiangyong Wang, Dehui Li, Guizai Gao, Jie Chen, Yufen Chen, Bahayila Halian, Fang Wang
更新时间: 2021-10-07
摘要: Phytolith-occluded organic carbon (PhytOC) sequestration is an important contributor to long-term carbon storage in grassland ecosystems. In this study, 28 typical plant communities of the Songnen grassland in China, consisting of Poaceae, Cyperaceae and Asteraceae community types, were selected for the analysis of phytoliths and PhytOC. The phytolith content, carbon content of phytolith, and PhytOC in biomass in each community were then measured. In addition, the statistical relationships between these three were analyzed, and the relationship between the percentage of phytoliths and PhytOC sequestration potential was determined so as to explore the PhytOC sequestration mechanism. Our principal results are as follows: (1) The annual PhytOC yield of Songnen grassland is 1.67 kg CO2 hm−2 yr−1. (2) In 28 communities, there are significant negative correlations between the contents of phytoliths and PhytOC (R2 = 0.943, P < 0.05) and between the contents of phytoliths and PhytOC biomass (R2 = 0.312, P < 0.05). However there is a significant positive correlation between the carbon content of phytolith and PhytOC in biomass (R2 = 0.652, P < 0.05). (3) Short-cell phytoliths make a greater contribution to PhytOC sequestration, and we speculated that this is due to the formation process of short-cell phytoliths and their high productivity in this grassland. Furthermore based on the above, we proposed some management measures to increase the PhytOC sequestration rate of the entire ecosystem.

258. 题目: The role of clay content and mineral surface area for soil organic carbon storage in an arable toposequence
文章编号: N21100703
期刊: Biogeochemistry
作者: Steffen A. Schweizer, Carsten W. Mueller, Carmen Höschen, Pavel Ivanov, Ingrid Kögel-Knabner
更新时间: 2021-10-07
摘要: Correlations between organic carbon (OC) and fine mineral particles corroborate the important role of the abundance of soil minerals with reactive surfaces to bind and increase the persistence of organic matter (OM). The storage of OM broadly consists of particulate and mineral-associated forms. Correlative studies on the impact of fine mineral soil particles on OM storage mostly combined data from differing sites potentially confounded by other environmental factors. Here, we analyzed OM storage in a soil clay content gradient of 5–37% with similar farm management and mineral composition. Throughout the clay gradient, soils contained 14 mg OC g −1 on average in the bulk soil without showing any systematic increase. Density fractionation revealed that a greater proportion of OC was stored as occluded particulate OM in the high clay soils (18–37% clay). In low clay soils (5–18% clay), the fine mineral-associated fractions had up to two times higher OC contents than high clay soils. Specific surface area measurements revealed that more mineral-associated OM was related to higher OC loading. This suggests that there is a potentially thicker accrual of more OM at the same mineral surface area within fine fractions of the low clay soils. With increasing clay content, OM storage forms contained more particulate OC and mineral-associated OC with a lower surface loading. This implies that fine mineral-associated OC storage in the studied agricultural soils was driven by thicker accrual of OM and decoupled from clay content limitations.

259. 题目: “Triple locks” on soil organic carbon exerted by sphagnum acid in wetlands
文章编号: N21100702
期刊: Geochimica et Cosmochimica Acta
作者: Yunpeng Zhao, Chengzhu Liu, Simin Wang, Yiyun Wang, Xiaoqing Liu, Wanqing Luo, Xiaojuan Feng
更新时间: 2021-10-07
摘要: Sphagnum acid, a major phenolic metabolite of Sphagnum mosses, is considered to play a key role in the remarkable accumulation of organic matter in Sphagnum-dominated wetlands. However, while previous studies have mainly focused on the antimicrobial property of Sphagnum metabolites, the effects of sphagnum acid on other soil biogeochemical processes related to soil organic carbon (SOC) stabilization are poorly investigated. Here we employ a series of incubation experiments involving sphagnum acid amendment into natural wetland soils and artificial reaction systems to comprehensively evaluate potential pathways driving SOC stabilization by sphagnum acid. We show that sphagnum acid greatly enhances the reductive dissolution of ferric iron [Fe(III)] (hydr)oxides in both wetland soils and synthetic Fe(III)-organic matter complexes, induces the formation of amorphous and poorly-crystalline Fe(III) and increases Fe-bound organic carbon. Furthermore, sphagnum acid quenches hydroxyl radicals produced by Fenton reactions during redox oscillations and indirectly suppresses the activity of phenol oxidase and β-glucosidase by inhibiting microbial activity, acidification and increasing enzyme sorption to newly formed Fe(III). Hence, sphagnum acid exerts “triple locks” on SOC through (i) Fe protection of organic matter, (ii) radical quenching, and (iii) microbial suppression. These important but under-investigated pathways are all closely related to Fe transformation, highlighting the key role of Sphagnum metabolite–Fe–organic matter interactions in regulating wetland soil carbon sinks. Changing distribution of Sphagnum under climate change and human activity will have cascading effects on soil Fe species, microbial activity and SOC stabilization, which warrants further investigation in the attempt to protect and increase wetland soil carbon stocks.

260. 题目: Evaluating landfill leachate treatment by organic municipal solid waste-derived biochar
文章编号: N21100702
期刊: Environmental Science: Water Research & Technology
作者: Matthew J Bentley, Michelle E Solomon, Brooke M Marten, Kyle K Shimabuku, Sherri M Cook
更新时间: 2021-10-07
摘要: Transforming the organic fraction of municipal solid waste (OFMSW) into biochar to reduce fugitive landfill emissions and control organic micropollutants (OMP) during landfill leachate treatment could provide a new circular economy organics diversion approach.

 共 13638 条记录  本页 20 条  本页从 241-260 条  13/682页  首页 上一页  8 9 10 11 12 13 14 15 16 17 18  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。