Biodegradation of Petroleum Hydrocarbons by Pseudomonas putida Strain MHF 7109

Pseudomonas putida MHF 7109 has been isolated and identified from cow dung microbial consortium for biodegradation of selected petroleum hydrocarbon compounds – benzene, toluene, and o‐xylene (BTX). Each compound was applied separately at concentrations of 50, 100, 250, and 500 mg L^?1 in minimal salt medium to evaluate degradation activity of the identified microbial strain. The results indicated that the strain used has high potential to degrade BTX at a concentration of 50 mg L^?1 within a period of 48, 96, and 168 h, respectively; whereas the concentration of 100 mg L^?1 of benzene and toluene was found to be completely degraded within 120 and 168 h, respectively. Sixty‐two percent of o‐xylene were degraded within 168 h at the 100 mg L^?1 concentration level. The maximum degradation rates for BTX were 1.35, 1.04, and 0.51 mg L^?1 h^?1, respectively. At higher concentrations (250 and 500 mg L^?1) BTX inhibited the activity of microorganisms. The mass spectrometry analysis identified the intermediates as catechol, 2‐hydroxymuconic semialdehyde, 3‐methylcatechol, cis‐2‐hydroxypenta‐2,4‐dienoate, 2‐methylbenzyl alcohol, and 1,2‐dihydroxy‐6‐methylcyclohexa‐3,5‐dienecarboxylate, for BTX, respectively. P. putida MHF 7109 has been found to have high potential for biodegradation of volatile petroleum hydrocarbons.     

The Seashell Wastes as Biosorbent for Reactive Dye Removal from Textile Effluents

This study investigates structural and adsorption properties of the powdered waste shells of Rapana gastropod and their use as a new cheap adsorbent to remove reactive dye Brilliant Red HE‐3B from aqueous solutions under batch conditions. For the powder shells characterization, solubility tests in acidic solutions and X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDX), Fourier transform IR spectroscopy (FT‐IR) and thermogravimetric analyses were performed. The results revealed that the adsorbent surface is heterogeneous consisting mainly from calcium carbonate layers (either calcite or aragonite) and a small amount of organic macromolecules (proteins and polysaccharides). The dye adsorptive potential of gastropod shells powder was evaluated as function of initial solution pH (1–5), adsorbent dose (6–40 g L^?1), dye concentration (50–300 mg L^?1), temperature (5–60°C), and contact time (0–24 h). It was observed that the maximum values of dye percentage removal were obtained at the initial pH of solution 1.2, shells dose of 40 g L^?1, dye initial concentration of 50–50 mg L^?1 and higher temperatures; the equilibrium time decreases with increasing of dye concentration. It is proved that the waste seashell powder can be used as low cost bioinorganic adsorbent for dyes removal from textile wastewaters.     

Glutamic Acid Modified Fenton System for Degradation of BTEX Contamination

The present study employed a modified Fenton system that aims to extend the optimum pH range towards neutral conditions for studying the oxidation of benzene, toluene, ethyl benzene, xylenes (BTEX) using glutamic acid (Glu) as an iron chelator. Addition of 20 mM Glu greatly enhanced the oxidation rate of BTEX in modified Fenton system at pH 5–7. A rapid mass destruction (>97% after 1 h) of BTEX as a water contaminant carried out in the presence of 500 mM H₂O₂, 10 mM Fe²⁺, and 20 mM Glu at pH 5 could be shown. The efficiency of this modified Fenton's system for mass destruction of BTEX in contaminated water was measured to estimate the impact of the major process variables that include initial concentrations of soluble Fe, H₂O₂, Glu (as metal chelating agent), and reaction time.     

Quantification of Diclofenac in Hospital Effluent and Identification of Metabolites and Degradation Products

In this study the occurrence of diclofenac and sub‐products in effluent emerging from the University Hospital at the Federal University of Santa Maria was investigated. One metabolite was identified and, in aqueous solution, three degradation products. The quantification was conducted by means of HPLC‐DAD, and the determination of metabolite and degradation products by LC–ESI–MS/MS–QTrap. For the HPLC‐DAD method, a 70:30 mixture of methanol/sodium phosphate was used in isocratic mode. For the LC–ESI–MS/MS–QTrap determinations, a mobile phase, where phase A was an ammonium acetate solution 5 × 10^?3 mol L^?1, and phase B was methanol (5 × 10^?3 mol L^?1)/ammonium acetate (9:1, v/v), on gradient mode. The LDs for the HPLC and LC–MS/MS methods, respectively, were 2.5 and 0.02 µg L^?1, the LQs, 8.3 and 0.05 µg L^?1, and the linear range from 10 up to 2000 µg L^?1 and 0.05 up to 10 µg L^?1. As expected, the LC–ESI–MS/MS–QTrap method was more sensitive and less laborious. The metabolite 4′‐hydroxy‐diclofenac was identified. Photolysis was used for the degradation studies and three products of diclofenac were identified (m/z of 214, 286 and 303) in aqueous solution. These results notwithstanding, no degradation products of diclofenac were found in the hospital effluent.     

Effects of sediment load on hydraulics of overland flow on steep slopes

Eroded sediment may have significant effects on the hydraulics of overland flow, but few studies have been performed to quantify these effects on steep slopes. This study investigated the potential effects of sediment load on Reynolds number, Froude number, flow depth, mean velocity, Darcy–Weisbach friction coefficient, shear stress, stream power, and unit stream power of overland flow in a sand‐glued hydraulic flume under a wide range of hydraulic conditions and sediment loads. Slope gradients were varied from 8·7 to 34·2%, unit flow rates from 0·66 to 5·26×10^?3 m² s^?1, and sediment loads from 0 to 6·95 kg m^?1 s^?1. Both Reynolds number (Re) and Froude number (Fr) decreased as sediment load increased, implying a decrease in flow turbulence. This inverse relationship should be considered in modeling soil erosion processes. Flow depth increased as sediment load increased with a mean value of 1·227 mm, caused by an increase in volume of sediment‐laden flow (contribution 62·4%) and a decrease in mean flow velocity (contribution 37·6%). The mean flow velocity decreased by up to 0·071 m s^?1 as sediment load increased. The Darcy–Weisbach friction coefficient (f) increased with sediment load, showing that the total energy consumption increased with sediment load. The effects of sediment load on f depended on flow discharge: as flow discharge increased, the influence of sediment load on f decreased due to increased flow depth and reduced relative roughness. Flow shear stress and stream power increased with sediment load, on average, by 80·5% and 60·2%, respectively; however, unit stream power decreased by an average of 11·1% as sediment load increased. Further studies are needed to extend and apply the insights obtained under these controlled conditions to real‐world overland flow conditions. Copyright © 2010 John Wiley & Sons, Ltd.     

Influence of grass soil cover on water runoff and soil detachment under rainfall simulation in a sub‐humid South African degraded rangeland

In most regions of the world overgrazing plays a major role in land degradation and thus creates a major threat to natural ecosystems. Several feedbacks exist between overgrazing, vegetation, soil infiltration by water and soil erosion that need to be better understood. In this study of a sub‐humid overgrazed rangeland in South Africa, the main objective was to evaluate the impact of grass cover on soil infiltration by water and soil detachment. Artificial rains of 30 and 60 mm h^?1 were applied for 30 min on 1 m² micro‐plots showing similar sandy‐loam Acrisols with different proportions of soil surface coverage by grass (Class A: 75–100%; B: 75–50%; C: 50–25%; D: 25–5%; E: 5–0% with an outcropping A horizon; F: 0% with an outcropping B horizon) to evaluate pre‐runoff rainfall (Pr), steady state water infiltration (I), sediment concentration (SC) and soil losses (SL). Whatever the class of vegetal cover and the rainfall intensity, with the exception of two plots probably affected by biological activity, I decreased regularly to a steady rate <2 mm h^?1 after 15 min rain. There was no significant correlation between I and Pr with vegetal cover. The average SC computed from the two rains increased from 0·16 g L^?1 (class A) to 48·5 g L^?1 (class F) while SL was varied between 4 g m^?2 h^?1 for A and 1883 g m^?2 h^?1 for F. SL increased significantly with decreasing vegetal cover with an exponential increase while the removal of the A horizon increased SC and SL by a factor of 4. The results support the belief that soil vegetation cover and overgrazing plays a major role in soil infiltration by water but also suggest that the interrill erosion process is self‐increasing. Abandoned cultivated lands and animal preferred pathways are more vulnerable to erosive processes than simply overgrazed rangelands. Copyright © 2011 John Wiley & Sons, Ltd.     

Degradation of glacial deposits quantified with cosmogenic nuclides,Quartermain Mountains,Antarctica

Many glacial deposits in the Quartermain Mountains, Antarctica present two apparent contradictions regarding the degradation of unconsolidated deposits. The glacial deposits are up to millions of years old, yet they have maintained their meter‐scale morphology despite the fact that bedrock and regolith erosion rates in the Quartermain Mountains have been measured at 0·1–4·0 m Ma^?1. Additionally, ground ice persists in some Miocene‐aged soils in the Quartermain Mountains even though modeled and measured sublimation rates of ice in Antarctic soils suggest that without any recharge mechanisms ground ice should sublimate in the upper few meters of soil on the order of 10³ to 10⁵ years. This paper presents results from using the concentration of cosmogenic nuclides beryllium‐10 (¹⁰Be) and aluminum‐26 (²⁶Al) in bulk sediment samples from depth profiles of three glacial deposits in the Quartermain Mountains. The measured nuclide concentrations are lower than expected for the known ages of the deposits, erosion alone does not always explain these concentrations, and deflation of the tills by the sublimation of ice coupled with erosion of the overlying till can explain some of the nuclide concentration profiles. The degradation rates that best match the data range 0·7–12 m Ma^?1 for sublimation of ice with initial debris concentrations ranging 12–45% and erosion of the overlying till at rates of 0·4–1·2 m Ma^?1. Overturning of the tills by cryoturbation, vertical mixing, or soil creep is not indicated by the cosmogenic nuclide profiles, and degradation appears to be limited to within a few centimeters of the surface. Erosion of these tills without vertical mixing may partially explain how some glacial deposits in the Quartermain Mountains maintain their morphology and contain ground ice close to the surface for millions of years. Copyright © 2010 John Wiley & Sons, Ltd.     

Degradation and Leaching of Napropamide in BRIS Soil Amended with Chicken Dung and Palm Oil Mill Effluent

The degradation and leaching of napropamide were compared between Beach Ridges Interspersed with Swales (BRIS) soil samples, and the same soil samples amended with 20 mg ha^?1 of either chicken dung (CD) or palm oil mill effluent (POME). The effects of removing dissolved organic carbon (DOC) from the soil samples on napropamide degradation and leaching were also studied. The addition of CD and POME to BRIS soil increased the napropamide half‐life values to 69 and 49.5 days, respectively. Sterilization of the soil samples resulted in partial inhibition of napropamide degradation in all soil samples. The half‐lives of napropamide in BRIS soils receiving 0, 20, 100, and 200 mg kg^?1 of DOC derived from CD were 43, 46.2, 53.4, and 63 days, respectively. The napropamide half‐lives in soil samples treated with 0, 20, 100, and 200 mg kg^?1 of DOC derived from POME were 43, 49.2, 57.7, and 69 days, respectively. However, in the sterilized soil samples, there were no significant effects of adding DOC derived from either CD or POME on napropamide half‐lives. Incorporating either CD or POME decreased napropamide leaching and total amounts of napropamide remained in the soil columns after two pore volumes of water has been leached were higher in the amended than the non‐amended soil. The CD was more effective in decreasing napropamide leaching than the POME. There were no effects of DOC on napropamide leaching in all soil treatments.     

Spinel Ferrite Mediated Photo‐Fenton Degradation of Phenolic Analogues: A Detailed Study Employing Two Distinct Inorganic Oxidants

The present work demonstrates the applicability of ferrites as photo‐Fenton catalysts for deterioration of different phenolic derivatives. To analyze optimal reaction conditions, experiments are performed with four magnetic spinel ferrites MFe₂O₄ (M = Co, Cu, Ni, and Zn) and two inorganic oxidants, i.e., hydrogen peroxide (HP) and potassium peroxymonosulfate (PMS). The reactions are performed using p‐nitrophenol as phenolic probe. CuFe₂O₄ and CoFe₂O₄ possessed excellent ability to activate HP and PMS, respectively, among all four synthesized catalysts. A noteworthy aspect of two oxidizing agents is that the concentration of PMS used during the reaction is four times less than HP. Further, the broad pH activity of PMS provides a significant advantage over HP. The optimal reaction conditions, when HP is the oxidant in the photo‐Fenton degradation, are 0.50 g L^?1 MFe₂O₄, pH 2.5, and 8.8 mM HP. Although PMS is active in a wide pH range (2–10), adequate reaction conditions are 0.50 g L^?1 MFe₂O₄, natural pH, and 2.2 mM PMS. The photo‐Fenton activity of ferrites is extended to the degradation of different nitro‐ and chloro‐analogs of phenol (2‐nitrophenol, 3‐nitrophenol, 4‐nitrophenol, 2,4‐dinitrophenol, 2,4,6‐trinitrophenol, 2‐chlorophenol, 3‐chlorophenol, 4‐chlorophenol, 2,4‐dichlorophenol) with only two ferrites (CuFe₂O₄ and CoFe₂O₄). A comparative study is performed with the two oxidants (HP and PMS) with positive results. Finally, stability and reusability of magnetic ferrites as catalysts are also studied to prove their use in phenolic solution treatment.     

Hydrological processes controlling ground and surface water flow from a hypermaritime forest–peatland complex,Diana Lake Provincial Park,British Columbia,Canada

The proposed harvesting of previously undeveloped forests in north coastal British Columbia requires an understanding of hydrological responses. Hydrometric and isotopic techniques were used to examine the hydrological linkages between meteoric inputs to the surface‐groundwater system and runoff response patterns of a forest‐peatland complex. Quickflow accounted for 72–91% of peak storm discharge. The runoff ratio was lowest for open peatland areas with thick organic horizons (0·02–0·05) due to low topographic gradients and many surface depressions capable of retaining surface water. Runoff ratio increased comparatively for ephemeral surface seep flows (0·06–0·40) and was greatest in steeply sloping forest communities with more permeable soils (0·33–0·69). The dominant mechanism for runoff generation was saturated shallow subsurface flow. Groundwater fluxes from the organic horizon of seeps (1·70–1·72 m³ day^?1 m^?1) were an important component of quickflow. The homogeneous δ²H? δ¹⁸O composition of groundwater indicated attenuation of the seasonal rainfall signal by mixing during recharge. The positive correlation (r² = 0·64 and 0·38, α = 0·05) between slope index and δ¹⁸O values in groundwater suggests that the spatial pattern in the δ¹⁸O composition along the forest‐peatland complex is influenced by topography and provides evidence that topographic indices may be used to predict groundwater residence time. Copyright © 2006 John Wiley & Sons, Ltd.     

Ultrasound Accelerated Oxidation of Organic Dyes by a Micron‐Sized Copper/Peroxomonosulfate System

Experiments on the degradation of acid orange 7 (AO7) using micron‐sized zero‐valent copper (ZVC) are conducted in acidic aqueous solution under ultrasonic (US) irradiation. The US/ZVC/peroxymonosulfate (PMS) process for AO7 degradation is significantly better than that of an independent system. Based on the characterization of ZVC, it is observed that the corrosion speed of ZVC increases after ultrasound, owing to which a greater amount of Cu⁺ (0–3.03 mg L^?1) and Cu²⁺ are produced. Exposure to US irradiation increases the available surface area of the catalysts to generate many new reactive sites for the degradation process. The AO7 degradation rate after the addition of a new copper reagent—neocuproine hemihydrate—from 6.33% to 100% proved that Cu⁺ is the main activator of PMS. Results indicated that free radicals (OH^? and SO₄^??) act as activators of PMS in the process. And higher ultrasound power, lower solution pH, and a larger ZVC dose are favorable for AO7 removal.     

Potassium and Residue Management Options to Enhance Productivity and Soil Quality in Zero Till Maize–Wheat Rotation

Crop residue burning and imbalanced use of chemical fertilizers in intensive cereal–cereal rotations are present ecological threats in any agro‐ecosystem of the world. Therefore, identification of best suitable agricultural practices can be a feasible option. The present experiment was initiated in 2013 and consisted of four residue levels (0, 2, 4, and 6 Mg ha^?1) and five potassium (K) levels (0, 50, 100, 150% recommended dose of K and 50%RDK+K solubilizing bacteria, KSB). Crop residue (CR) and K management significantly improve crop and soil quality associated parameters. Among the treatments, maximum increase in crop growth, physiological parameters, grain yield, quality aspects, and water productivity are recorded with the application of 4–6 Mg ha^?1 CR. Application of 50%RDK+KSB also significantly increases crop and soil related parameters. Soil quality indicators (bulk density, pH, electrical conductivity, and available micronutrients) do not vary significantly with CR and K management. Change in soil organic carbon status, soil enzymes, and potassium‐solubilizing bacterial count are significantly increased with 4–6 Mg ha^?1 CR and application of 50%RDK+KSB, and this is in accordance with correlation study carried out. Therefore, it is concluded that CR retention (4–6 Mg ha^?1) and reduction of inorganic K fertilizer by 50% and inoculation of KSB enhance the soil quality indicators and thereby improve crop growth, physiological parameters, grain yield, and quality aspects along with water productivity under zero till maize–wheat rotation.     

Biologischer Abbau von 2,4-Dinitrotoluol in einer kontinuierlich betriebenen Versuchsanlage und kinetische Untersuchungen

Biological Degradation of 2,4-Dinitrotoluene in a Continuous Bioreactor and Kinetic Studies Experimental results on the aerobic biological degradation with complete mineralization of 2,4-dinitrotoluene (2,4-DNT) are presented. A culture of Pseudomonas sp. DNT from Spain and Nishino was used. The degradation was examined with batch cultures for the determination of kinetic and stoichiometric coefficients. Further experiments were carried out with a continuous culture in a fixed-bed reactor with recirculation in order to obtain high degradation rates. The reactor was packed with ceramic Raschig rings (55 mL) and had a liquid reaction volume of 160 mL. The minimal salt media from Spanggord et al. with and without (NH₄)₂S)₄ as nitrogen source was used as substrate. 2,4-DNT was the sole source of carbon and energy. From batch experiments a yield coefficient Y_B/S = (0.30 ± 0.05) g g^?1 was calculated from a mass balance of the elements. This result was confirmed by calculations using literature data. Fitting the experimental data to the Monod equation, μ_max = 0.1 h^?1 and K_S = 0.01…0.03 mmol L^?1 were obtained. It was demonstrated by batch experiments that 2,4-DNT is not only used as the source of carbon and energy but also as the nitrogen source. In the fixed-bed reactor, a degradation of 92…97% was reached with a maximal 2,4-DNT load of 95 mg L^?1 h^?1. The rate of continuous degradation could be described by a pseudo-first-order reaction (k = 9.73 h^?1). The complete mineralization of 2,4-DNT was verified by the measurement of DOC and the formed nitrite and nitrate. The formed nitrite was nitrified simultaneously. It was demonstrated by these experiments that large scale biological treatment of industrial effluent containing 2,4-DNT may be successful.     

Determination of the lifetime of molecules O 2 + and estimation of the flux of penetrating electrons generating a cloud of excess concentration of O 2 + in the ionosphere at altitudes above 220 km

The occurrence of anomalous (nonthermal) profiles of green emission of oxygen atoms detected with a Fabry-Perot spectrometer in auroras with the effect of a rapid decrease in the intensity of the wings of their dissociative component has been investigated. Based on an analysis of these measured profiles, it has been found that the characteristic time of recombination of a molecular oxygen ion at altitudes of 200–400 km is about 5–7 s. It appears that these molecular ions occur in a horizontally limited region of the auroral ionosphere as a result of ionization by a space localized flux of soft electrons with energies of 0.2–0.4 keV penetrating up to altitudes of 200 km. The estimation of the electron flux produces a value of 10¹⁰–10¹³ electrons cm^?2 s^?1. They generate the excess concentration n(O ₂ ⁺ ) ~ 5.6 × 10⁵ cm^?3.     

Evaluating the transport and removal of chromate using pyrite and biotite columns

To remove chromate from a wastewater, a porous permeable reactive barrier system (PRBS), using pyrite and biotite, was adapted. This study included bench‐scale column experiments to evaluate the efficiency of the PRBS and investigate the reaction process. The total chromium concentration of the effluent from the biotite and pyrite columns reached the influent concentration of 0·10 mM after passing through more than 150 pore volumes (PVs) and 27 PVs respectively, and remained constant thereafter. The Cr^VI concentration in the effluent from the biotite column became constant at about 0·08 mM , accounting for approximately 80% of the influent concentration, after passing through 200 PVs. Moreover, in the pyrite column, the Cr^VI concentration remained at about 0·01 mM , 10% of the input level, after passing through 116 PVs. This shows that both columns maintained their levels of chromate reduction once the Cr^VI breakthrough curves (BTCs) had reached the steady state, though the steady‐state output concentration of total chromium had reached the influent level. The variances of the iron concentration closely followed those of the chromium. The observed data for both columns were fitted to the predicted BTCs calculated by CXTFIT, a program for estimating the solute transport parameters from experimental data. The degradation coefficient µ of the total chromium BTCs for both columns was zero, suggesting the mechanisms for the removal of chromate limit the µ of the Cr^VI BTCs. The Cr^VI degradation of the pyrite column (6·60) was much greater than that of the biotite column (0·27). In addition, the Cr^VI retardation coefficient R of the pyrite column (253) was also larger than that of the biotite column (125). The R values for the total chromium BTCs from both columns were smaller than those of the Cr^VI BTC. Whereas the total chromium BTC for the pyrite column showed little retardation (1·5), the biotite column showed considerable retardation (80). The results for the 900 °C heat‐treated biotite column were analogous to those of the control column (quartz sand). This suggests that the heat‐treated biotite played no role in the retardation and removal of hexavalent chromium. The parameters of the heat‐treated biotite were calculated to an R of 1·2 and µ of 0·01, and these values confirmed quantitatively that the heated biotite had little effect on the transport of Cr^VI. These solute transport parameters, calculated by CXTFIT from the data obtained from the column tests, can provide quantitative information for the evaluation of bench‐ or field‐scale columns as a removal technology for Cr^VI in wastewater or contaminated groundwater. Copyright © 2006 John Wiley & Sons, Ltd.     

Increased levels of petroleum hydrocarbons in the surface sediments of Swedish coastal waters

Petroleum hydrocarbons in the sediments of the Bothnian Bay, Baltic proper, Öresund, Kattegatt and Skagerrak were analysed in a survey of oil pollution along the Swedish coast in 1974 and 1975. Sixty-one of these sediment stations were revisited in 1982 and analysed with the methods used in the first survey. The mean content of petroleum hydrocarbons (paraffin-naphthene fraction) in the sediment surface showed a statistically significant increase from 199 to 252 μg g^?1 dry wt. The main increase had taken place in the coastal areas. Within 0–20 km distance of urbanized areas (>20 000 inhabitants) petroleum hydrocarbons had increased from 371 to 447 μg g^?1. Sediment levels increased from 76 to 117 μg g^?1, 20–50 km from urbanized areas. The increase in these areas was equivalent to 0.119 g m^?2 yr^?1.     

Efficiency of Pleurotus florida Laccase on Decolorization and Detoxification of the Reactive Dye Remazol Brilliant Blue R (RBBR) under Optimized Conditions

Laccase from the white‐rot fungus Pleurotus florida, produced under solid‐state fermentation conditions, was used for the decolorization of reactive dye Remazol Brilliant Blue R (RBBR). RBBR was decolorized up to 46% by P. florida laccase alone in 10 min. In the presence of N‐hydroxybenzotriazole (HBT), the rate of decolorization was enhanced 1.56‐fold. Central composite design of response surface methodology with four variables namely, dye, enzyme, redox mediator concentrations, and time at five levels was applied to optimize the RBBR decolorization. The predicted optimum level of variables for maximum RBBR decolorization (87%) was found to be 52.90 mg L^?1 (RBBR), 1.87 U mL^?1 (laccase), 0.85 mM (HBT), and 7.17 min (time), respectively. The validation results showed that the experimental value of RBBR decolorization (82%) was close to the predicted one. The disappearance of C–N and C–X groups, and a small shift in N–H groups in Fourier‐transform infra red (FTIR) spectroscopy confirms the degradation of RBBR chromophore by laccase enzyme. The phytotoxicity of RBBR was considerably reduced after the treatment with laccase. RBBR decolorization kinetics; K_m and V_max were calculated to be 145.82 mg L^?1 and 24.86 mg L^?1 min, respectively.     

Effects of Nitrogen Fertilization on Soil Microbial Biomass and Community Functional Diversity in Temperate Grassland in Inner Mongolia,China

Nitrogen (N) fertilization may profoundly affect soil microbial communities. In this study, a field fertilization experiment was conducted in temperate grassland in Inner Mongolia, China to examine the effect of N fertilization on soil microbial properties and the main factors related to the characteristics of soil microbial community. Soil microbial biomass carbon (MBC) and microbial functional diversity along an N gradient were measured over three months (June to August). The result showed that N fertilization significantly decreased MBC under high N treatment (N200, 200 kg N ha^?1 y^?1) compared with the control (N0, 0 kg N ha^?1 y^?1) in the three months. Microbial functional diversity in July and August were significantly increased by low N treatment (N50, 50 kg N ha^?1 y^?1). Among the three fertilization treatments, microbial functional diversity under N200 in the three months was significantly lower than that of N50. The decrease of MBC and functional diversity under N200 were mainly due to the significant decline of plant belowground biomass under high N treatment. The increase of functional diversity under N50 treatment was due to the higher plant aboveground biomass as a result of the higher soil moisture availability. This finding highlighted that the higher N fertilization (N200) was not suitable for the growth and improvement of functional diversity of the soil microbial community, and that site and plant community play an important role in regulating the characteristics of soil microbial community.     

Solar eclipse of August 1, 2008, above Kharkov: 2. Observation results of wave disturbances in the ionosphere

Quasi-periodic variations in the power of incoherent scattered signals, caused by wave disturbances of the electron concentration in the ionosphere, are analyzed for the day of a partial solar eclipse and for a background day. The windowed and adaptive Fourier transforms and the wavelet transform are used for spectral analysis. The spectral parameters of the wave disturbances at altitudes of 100–500 km in the 10–120 min period range differed significantly on the day of the solar eclipse and on the background day. Variations in the spectrum began near the onset of the phase of maximum disk occultation and continued no less than 2 h. The amplitude of time variations N was 2 × 10⁹–4 × 10¹⁰ m^?3, and the relative amplitude was 0.10–0.15. Wave disturbances have been compared for five solar eclipses; the comparison shows a noticeable variation in the spectrum of the wave disturbances during these events.     

Development of a river delta: a case study of Cimanuk river mouth,Indonesia

This paper describes delta development processes with particular reference to Cimanuk Delta in Indonesia. Cimanuk river delta, the most rapidly growing river delta in Indonesia, is located on the northern coast of Java Island. The delta is subject to ocean waves of less than 1 m height due to its position in the semi‐enclosed Java Sea in the Indonesian archipelago. The study has been carried out using a hydrodynamic model that accounts for sediment movement through the rivers and estuaries. As an advanced approach to management of river deltas, a numerical model, namely MIKE‐21, is used as a tool in the management of Cimanuk river delta. From calibration and verification of hydrodynamic model, it was found that the best value of bed roughness was 0·1 m. For the sediment‐transport model, the calibration parameters were adjusted to obtain the most satisfactory results of suspended sediment concentration and volume of deposition. By comparing the computed and observed data in the calibration, the best values of critical bed shear stress for deposition, critical bed shear stress for erosion and erosion coefficient were 0·05 N m^?2, 0·15 N m^?2, and 0·00001 kg m^?2 s^?1, respectively. The calibrated model was then used to analyse sensitivity of model parameters and to simulate delta development during the periods 1945–1963 and 1981–1997. It was found that the sensitive model parameters were bed shear stresses for deposition and erosion, while the important model inputs were river suspended sediment concentration, sediment characteristics and hydrodynamic. The model result showed reasonable agreement with the observed data. As evidenced by field data, the mathematical model proves that the Cimanuk river delta is a river‐dominated delta because of its protrusion pattern and very high sediment loads from the Cimanuk river. It was concluded that 86% of sediment load from the Cimanuk river was deposited in the Cimanuk delta. Copyright © 2008 John Wiley & Sons, Ltd.