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Preliminary Effects of Fertilization on Ecochemical Soil Condition in Mature Spruce Stands Experiencing Dieback in the Beskid Śląski and Żywiecki Mountains, Poland Texte intégral
2014
Małek, Stanisław | Januszek, Kazimierz | Keeton, William S. | Barszcz, Józef | Kroczek, Marek | Błońska, Ewa | Wanic, Tomasz
In recent years, there has been the phenomena of spruce dieback in Europe. Significant areas of spruce low mortality now cover both sides of the Polish southern border. We evaluated ecochemical parameters influencing the heavy dieback occurring in mature spruce stands in the Polish Carpathian Mountains. Dolomite, magnesite and serpentinite fertilizers were applied to experimental plots located in 100-year-old stands in the autumn of 2008. The experimental plots were located in the mid-elevational forest zone (900–950 m) on two nappes of the flysch Carpathians: Magura (Ujsoły Forest District) and Silesian (Wisła Forest District). The saturation of the studied soils demonstrates moderate resilience of soils in Wisła Forest District in relation to acid load and high flexibility of the Ujsoły soils. After application of the fertilizers, an increase of Mg, Ca and Mb was noted in the soil solution, determined in the overlaying highly acidic organic horizons through the ion-exchange buffering mechanism of highly protonated functional groups with high buffering capacity. Magnesium concentration increased following fertilization, presenting a potential improvement of forest growth capacity without the hazard of adverse side effects of liming. Aluminium stress in old spruce is unlikely, while trees in the control plots in Wisła Forest District may already be sensitive to aluminium stress. Serpentinite fertilization improved the supply of soils in magnesium without causing significant changes in the pH of the soil. Such changes in the pH were found in dolomite and magnesite fertilizer.
Afficher plus [+] Moins [-]Adsorptive Removal of Trivalent Chromium in Aqueous Solution Using Precipitate Produced from Aluminum Tanning Wastewater Texte intégral
2014
Ma, Hongrui | Hua, Li | Lian, Kunzhou | Ma, Xiu
Precipitate adsorbent was produced from aluminum tanning wastewater by alkali precipitation and characterized by XPF, XRD, and FTIR. The results showed that the main components of the precipitate were Al, Ti, and Zr. The adsorption equilibrium for Cr³⁺ on the precipitate was reached within 60 min. The precipitate had better removal for Cr³⁺ from wastewater at pH 7.0. The kinetic process of adsorption can be described by the pseudo-second-order kinetic equation, and the adsorption isotherm fitted to the Langmuir model very well. Co-existed cations (Na⁺, Ca²⁺) in aqueous solution restrained Cr³⁺ adsorption on the precipitate. The adsorption of Cr³⁺ on the precipitate was mainly through the complexation and ion-exchange mechanisms, and oxide may play a major role in Cr³⁺ adsorption process.
Afficher plus [+] Moins [-]Denitrification controls in urban riparian soils: implications for reducing urban nonpoint source nitrogen pollution Texte intégral
2014
Li, Yangjie | Chen, Zhenlou | Lou, Huanjie | Wang, Dongqi | Deng, Huanguang | Wang, Chu
The purpose of this research was to thoroughly analyze the influences of environmental factors on denitrification processes in urban riparian soils. Besides, the study was also carried out to identify whether the denitrification processes in urban riparian soils could control nonpoint source nitrogen pollution in urban areas. The denitrification rates (DR) over 1 year were measured using an acetylene inhibition technique during the incubation of intact soil cores from six urban riparian sites, which could be divided into three types according to their vegetation. The soil samples were analyzed to determine the soil organic carbon (SOC), soil total nitrogen (STN), C/N ratio, extractable NO₃⁻-N and NH₄⁺-N, pH value, soil water content (SWC), and the soil nitrification potential to evaluate which of these factors determined the final outcome of denitrification. A nitrate amendment experiment further indicated that the riparian DR was responsive to added nitrate. Although the DRs were very low (0.099 ~ 33.23 ng N₂O-N g⁻¹ h⁻¹) due to the small amount of nitrogen moving into the urban riparian zone, the spatial and temporal patterns of denitrification differed significantly. The extractable NO₃⁻-N proved to be the dominant factor influencing the spatial distribution of denitrification, whereas the soil temperature was a determinant of the seasonal DR variation. The six riparian sites could also be divided into two types (a nitrate-abundant and a nitrate-stressed riparian system) according to the soil NO₃⁻-N concentration. The DR in nitrate-abundant riparian systems was significantly higher than that in the nitrate-stressed riparian systems. The DR in riparian zones that were covered with bushes and had adjacent cropland was higher than in grass-covered riparian sites. Furthermore, the riparian DR decreased with soil depth, which was mainly attributed to the concentrated nitrate in surface soils. The DR was not associated with the SOC, STN, C/N ratio, and pH. Nitrate supply and temperature finally decided the spatiotemporal distribution patterns of urban riparian denitrification. Considering both the low DR of existing riparian soils and the significance of nonpoint source nitrogen pollution, the substantial denitrification potential of urban riparian soils should be utilized to reduce nitrogen pollution using proper engineering measures that would collect the polluted urban rainfall runoff and make it flow through the riparian zones.
Afficher plus [+] Moins [-]Study on the dynamics of grass microgametophytes from urban vegetation Texte intégral
2014
Ratajová, Alena
Urban sprawl and increasing economical pressure on agricultural production raises new unprecedented environmental questions. The presented study proved that higher level of fertilization of the urban vegetation significantly increases the concentration of male microgametophytes in the air during the flowering season. The levels of fertilization had no significant effect on the pollen grain size, nor on the profile and content of the phenolic compounds, however, the content of tryptophan (protein with a key role in allergies) was significantly influenced. The metabolism of tryptophan and its role in human imunilogy is not yet completely understood, however, it is recommended to avoid unnecessary fertilization in urbanized areas.
Afficher plus [+] Moins [-]Detection of Total Phosphorus Concentrations of Turbid Inland Waters Using a Remote Sensing Method Texte intégral
2014
Sun, Deyong | Qiu, Zhongfeng | Li, Yunmei | Shi, Kun | Gong, Shaoqi
Phosphorus (P) is widely known as a limiting nutrient of water eutrophication for inland freshwater ecosystems. Owing to the complexity of P chemistry, remote sensing detection of total phosphorus (TP) concentrations currently remains limited especially for optically complex turbid inland waters. To address this need, a new TP remote sensing algorithm is developed based on prior water optical classification and the use of support vector regression (SVR) machine. The in situ observed datasets, used in this study, were collected at specific times during 2009 ~ 2011, covering a total of 232 stations from eight cruises in Lakes Taihu, Chaohu, Dianchi, and Three Gorges reservoir of China. Three types of waters were first classified by using a recently developed NTD675 (Normalized Trough Depth of spectral reflectance at 675 nm) water classification method. Then, spectral regions sensitive specifically to each water type were explored and expressed via several band ratios and used for retrieval algorithm development. The established type-specific SVR algorithms yield relatively high predictive accuracies. Specifically, the mean absolute percentage errors (MAPE) produced with the independent validation samples were achieved at 32.7, 23.2, and 14.1 % for type 1, type 2, and type 3 waters, respectively. Such water type-specific SVR algorithms are more accurate for the classified waters than an aggregated SVR algorithm for the nonclassified water and also superior to commonly used statistical algorithms. Moreover, application of the developed algorithms with HJ1A/HSI image data demonstrates that the algorithms have a large potential for remote sensing estimation of TP concentrations in optically complex turbid inland waters.
Afficher plus [+] Moins [-]Sustainable Removal of Nitrophenols by Rhizoremediation Using Four Strains of Bacteria and Giant Duckweed (Spirodela polyrhiza) Texte intégral
2014
Kristanti, Risky Ayu | Toyama, Tadashi | Hadibarata, Tony | Tanaka, Yasuhiro | Mori, Kazu-hiro
We examined the effectiveness of rhizoaugmentation for treating water contaminated with the nitrophenols (NPs), 2-NP, 3-NP, 4-NP, and 2,4-dinitrophenol (2,4-DNP) using NP-degrading bacteria. We used 2-NP-degrading Pseudomonas sp. (strain ONR1), 3-NP-degrading Cupriavidus sp. (MFR2), 4-NP-degrading Rhodococcus sp. (PKR1), 2,4-DNP-degrading Rhodococcus sp. (DNR2), and giant duckweed (Spirodela polyrhiza). The four bacterial strains readily colonized Spirodela roots, as approximately 1 × 10⁵colony-forming units [CFUs] plant⁻¹to 10⁶–10⁷ CFU plant⁻¹. The higher populations remained stable through five sequential 2-day degradation cycles and completely removed all four NPs within each cycle. The root–bacteria association also successfully treated wastewater effluent contaminated with NPs; 52–71 % of 2-NP and 100 % of 3-NP, 4-NP, and 2,4-DNP were removed within each of five 2-day cycles. These results demonstrate the potential of rhizoaugmentation to achieve efficient and sustainable treatment of NP-contaminated waters.
Afficher plus [+] Moins [-]Synthesis, Characterization, and Adsorptive Properties of Magnetic Cellulose Nanocomposites for Arsenic Removal Texte intégral
2014
Zhou, Shimin | Wang, Di | Sun, Haoyang | Chen, Jitao | Wu, Songhai | Na, Ping
In this study, the magnetic cellulose nanomaterials, containing magnetic nanoscale zerovalent iron (nZVI) and cellulose, were prepared by a novel reduction method and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometry (VSM). The XRD and XPS results demonstrated the formation of zerovalent iron nanoparticles in the nanocomposite materials. With a saturation magnetization of 57.2 emu g⁻¹, the cellulose@nZVI composites could be easily separated from solutions in 30 s through the external magnetic field. We investigated the adsorption performance of the magnetic cellulose nanomaterials for As(III) removal from aqueous solutions. The experimental results showed that arsenite adsorption followed the pseudo-second-order kinetic model and Langmuir isotherm model. A maximum removal of 99.27 % was observed for an initial concentration 10 mg L⁻¹, at pH 8.0, and an adsorbent dose of 1.0 g L⁻¹. Considering the high adsorption capacity, fast adsorption rate, and quick magnetic separation from treated water, the cellulose@nZVI composites were expected to be an efficient magnetic adsorbent for arsenic removal from aqueous solutions.
Afficher plus [+] Moins [-]Heather Moorland Vegetation and Air Pollution: A Comparison and Synthesis of Three National Gradient Studies Texte intégral
2014
Payne, Richard J. | Caporn, Simon J. M. | Field, Christopher D. | Carroll, Jacky A. | Edmondson, Jill L. | Britton, A. J. (Andrea Jane) | Dise, Nancy B.
Large-scale spatial gradient studies are increasingly used to understand the impacts of air pollution and devise appropriate conservation and policy responses, but how consistent are the conclusions we draw from these surveys? Here, we address this question by comparing three independent gradient studies from the same habitat, UK heather moorlands. We harmonise and re-analyse vegetation data from these surveys in relation to cumulative nitrogen deposition, sulphur deposition and other potential drivers and use these results to assess the possible impacts of air pollution in this habitat. Air pollution variables explain more variance in species richness and composition than other variables in the vast majority of analyses. Untangling the relative contribution of nitrogen and (legacy) sulphur deposition is difficult due to strong correlation, but it is likely that nitrogen deposition is currently the dominant driver of change. There is consistency in the negative correlation between species richness and nitrogen deposition, but some variability in the form of this relationship due to small sample sizes. Across surveys there is a high degree of consistency in species identified as either positively or negatively correlated to nitrogen deposition, and no evidence for systematic differences. We conclude that relatively small surveys across wide gradients can provide useful information on potential drivers of diversity, as well as identify sensitive and tolerant species. Our results strongly suggest that nitrogen deposition has a severe and widespread impact on the biodiversity of British heather moorlands and is causing changes in plant communities, including promoting the spread of at least one invasive species.
Afficher plus [+] Moins [-]Comparative Analysis of Azo Dye Biodegradation by Aspergillus oryzae and Phanerochaete chrysosporium Texte intégral
2014
Santos, Graziely Cristina | Corso, Carlos Renato
The textile industry often releases effluents into the environment without proper treatment or complete dye removal. Azo dyes, which are characterized by azo groups (―N═N―), are frequently used in the textile industry. Among the different wastewater treatment methods available, biological treatment has been extensively studied. The aim of the present study was to compare the biodegradation of the azo dye Direct Blue 71 by the fungi Phanerochaete chrysosporium and Aspergillus oryzae in paramorphogenic form using a 100 μg/ml dye solution. Biodegradation tests were performed within 240 h. The absorbance values obtained with UV-VIS spectrophotometry were used to determine the absorbance ratio and the percentage of dye discoloration following the biodegradation test. FTIR analysis allowed the identification of molecular compounds in the solution before and after biodegradation. Both A. oryzae and P. chrysosporium demonstrated considerable potential regarding the biodegradation of dyes in wastewater. These results may contribute toward improving effluent treatment systems in the textile industry.
Afficher plus [+] Moins [-]Simulation of CO2 and Attribution Analysis at Six European Peatland Sites Using the ECOSSE Model Texte intégral
2014
Abdalla, M. | Hastings, A. | Bell, M. J. | Smith, J. U. | Richards, M. | Nilsson, M. B. | Peichl, M. | Löfvenius, M. O. | Lund, M. | Helfter, C. | Nemitz, E. | Sutton, M. A. | Aurela, M. | Lohila, A. | Laurila, T. | Dolman, A. J. | Belelli-Marchesini, L. | Pogson, M. | Jones, E. | Drewer, J. | Drosler, M. | Smith, P.
In this study, we simulated heterotrophic CO₂(Rh) fluxes at six European peatland sites using the ECOSSE model and compared them to estimates of Rh made from eddy covariance (EC) measurements. The sites are spread over four countries with different climates, vegetation and management. Annual Rh from the different sites ranged from 110 to 540 g C m⁻². The maximum annual Rh occurred when the water table (WT) level was between −10 and −25 cm and the air temperature was above 6.2 °C. The model successfully simulated seasonal trends for the majority of the sites. Regression relationships (r²) between the EC-derived and simulated Rh ranged from 0.28 to 0.76, and the root mean square error and relative error were small, revealing an acceptable fit. The overall relative deviation value between annual EC-derived and simulated Rh was small (−1 %) and model efficiency ranges across sites from −0.25 to +0.41. Sensitivity analysis highlighted that increasing temperature, decreasing precipitation and lowering WT depth could significantly increase Rh from soils. Thus, management which lowers the WT could significantly increase anthropogenic CO₂, so from a carbon emissions perspective, it should be avoided. The results presented here demonstrate a robust basis for further application of the ECOSSE model to assess the impacts of future land management interventions on peatland carbon emissions and to help guide best practice land management decisions.
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