Tide and current observations in the central Chukchi Sea during the summer of 2012

Current data from a moored Acoustic Doppler Current Profiler(ADCP) deployed at 69?30.155′N,169?00.654′W in the central Chukchi Sea during 2012 summertime is analyzed in the present paper.Characteristics of tidal and residual currents are ob-tained with Cosine-Lanczos filter and cross-spectral analyses.The main achievements are as follows:1) Along with the local inertial frequency of 12.8 h,two other peaks at ~12-h and ~10-d dominate the time series of raw velocity;2) The M_2 dominates the 6 resolved tide constituents with significant amplitude variations over depth and the ratios of current speed of this constituent to that of the total tidal current are 54% and 47% for u and v components,respectively.All the resolved tidal constituents rotate clockwise at depth with the exception of MM and O1.The constituents of M_2 and S_2 with the largest major semi-axes are similar in eccentricity and orientation at deeper levels;3) The maximum of residual currents varies in a range of 20–30 cms~(-1) over depth and the current with lower velocities flow more true north with smaller magnitudes compared to the current in surface layer.The ~10 d fluctuation of residual current is found throughout the water column and attributed to the response of current to the local wind forcing,with an approximate 1.4 d lag-time at the surface level and occurring several hours later in the lower layer;4) Mean residual currents flow toward the north with the magnitudes smaller than 7 cms~(-1) in a general agreement with previous studies,which suggests a relatively weaker but stable northward flow indeed exists in the central Chukchi Sea.     

Phase characteristic analysis of continuous depth air-gun source wavelet

Air guns are important sources for marine seismic exploration. Far-field wavelet of air gun arrays, as a necessary parameter for pre-stack processing and source models, plays an important role during marine seismic data processing and interpretation. When an air gun fires, it generates a series of air bubbles. Similar to onshore seismic exploration, the water forms a plastic fluid near the bubble; the farther the air gun is located from the measurement, the more steady and more accurately represented the wavelet will be. In practice, hydrophones should be placed more than 100 m from the air gun; however, traditional seismic cables cannot meet this requirement. On the other hand, vertical cables provide a viable solution to this problem. This study uses a vertical cable to receive wavelets from 38 air guns and data are collected offshore Southeast Qiong, where the water depth is over 1000 m. In this study, the wavelets measured using this technique coincide very well with the simulated wavelets and can therefore represent the real shape of the wavelets. This experiment fills a technology gap in China.     

基于恐龙足迹重建攀西地区白垩纪恐龙动物群

攀西地区没有白垩纪恐龙骨骼化石记录,对该区白垩纪恐龙动物群组合的认识尚属空白。1991年,攀西地区首次发现了恐龙足迹,此后陆续发现了8个足迹点。这些足迹点共发现9种不同的非鸟恐龙足迹(6种非鸟兽脚类、1种蜥脚类和2种鸟脚类足迹),以及翼龙和龟类足迹。共11种足迹形态类型由185道行迹(与孤立足迹)组成,可能代表着同等数量的造迹者。其中飞天山组的组合多样性最强,小坝组和雷打树组较弱。这个相对全面的足迹数据库,为该地区白垩纪四足类的古生态学普查提供了动物群的组成信息,这在该缺乏骨骼化石的地区显得尤为重要。     

Provenance of buried esker groundwater: the case of Vars-Winchester esker aquifer,Eastern Ontario,Canada

An innovative mode of groundwater recharge to a buried esker aquifer is considered. The current conceptual model affords a natural safeguard to underlying aquifers from the overlying muds. A hypothesis of groundwater recharge to a buried esker aquifer via preferential pathways across its overlying muds is tested here by heuristic numerical one-dimensional and two-dimensional modeling simulations. The hypothesis has been tested against two other conventionally accepted scenarios involving: (1) distal esker outcrop areas and (2) remote shallow-bedrock recharge areas. The main evidence comes from documented recharge pressure pulses in the overlying mud aquitard and in the underlying esker hydraulic-head time series for the Vars-Winchester esker aquifer in Eastern Ontario, Canada. These perturbations to the potentiometric surface are believed to be the aquifer response to recharge events. The migration rate of these pressure pulses is directly related to the hydraulic diffusivity of the formation. The measured response time and response amplitude between singular radar precipitation events and well hydrographs constituted the heuristic model calibration targets. The main evidence also includes mud-layering deformation (water escape features) which was observed in seismic surveys of the over-esker muds. These disturbed stratigraphic elements provide a realistic mechanism for migrating water to transit through the muds. The effective hydraulic conductivities of these preferential pathways in the muds were estimated to be between 2?×?10^?6 and 7?×?10^?6 m/s. The implications of these findings relate to the alleged natural safeguard of these overlying muds.     

柴达木盆地西部地区咸化湖盆天然气地球化学特征及成因类型判识指标——以古近系—新近系为例

根据天然气地球化学基本理论,对柴达木盆地西部（柴西）地区天然气的地球化学特征进行分析。测试和收集该地区18个油气田及含油气构造的83个天然气样品,分析其组分和C同位素数据,结果显示,该区天然气以烃类气体为主,烃类含量介于79.24%~99.81%之间,天然气比重介于0.72~1.36之间,天然气干燥系数（C1/C2+）介于1.04~617.8之间,甲烷C同位素值介于-51.4‰~-24.2‰之间,乙烷C同位素值介于-34.2‰~-17.4‰之间。在此基础上,对该区不同构造带的天然气成因类型进行研究。研究结果表明,柴达木盆地西部地区天然气类型可划分为腐泥型气、腐殖型气、混合气3类,柴西北部天然气主要为腐泥型气和混合气,少量腐殖型气;柴西南部主要为腐泥型气,少量混合气。同时,建立了天然气成因类型的判识指标,对该区的天然气地球化学特征有了较为深入的认识,对今后的天然气勘探具有指导意义。     

Enhanced bioremoval of refractory compounds from dyeing wastewater using optimized sequential anaerobic/aerobic process

The upflow anaerobic sludge blanket process followed by the biological aerated filter process was employed to improve the removal of color and recalcitrant compounds from real dyeing wastewater. The highest removal efficiency for color was observed in the anaerobic process, at 8-h hydraulic retention time, seeded with the sludge granule. In the subsequent aerobic process packed with the microbe-immobilized polyethylene glycol media, the removal efficiency for chemical oxygen demand increased significantly to 75 %, regardless of the empty bed contact time. The average influent non-biodegradable soluble chemical oxygen demand was 517 mg/L, and the average concentration in effluent from the anaerobic reactor was 363 mg/L, suggesting the removal of some recalcitrant matters together with the degradable ones. The average non-biodegradable soluble chemical oxygen demand in effluent from the aerobic reactor was 87, 93, and 118 mg/L, with the removal efficiency of 76, 74, and 67 %, at 24-, 12-, and 8-h empty bed contact time, respectively. The combined anaerobic sludge blanket and aerobic cell-entrapped process was effective to remove the refractory compounds from real dyeing wastewater as well as in reducing organic loading to meet the effluent discharge limits. This integrated process is considered an effective and economical treatment technology for dyeing wastewater.     

Cannibalistic viruses in the aquatic environment: role of virophages in manipulating microbial communities

The ecological role of viruses in aquatic environments is gaining interest due to their abundance and overall diversity. Much focus has been on bacteriophages since they were found to play an important role in the diversification and sustainment at both the micro- and macro-scale. However, the discovery of virophages coexisting with giant viruses in a diverse set of eukaryotic hosts has recently gained attention. Virophages are small double-stranded DNA viruses found parasitizing giant viruses of eukaryotes. Since the discovery of the first virophage (Sputnik) many virophage signatures have been detected from a variety of environmental samples with specific infection cycles. In addition, these parasites display important roles in equilibrating microbial biomass, nutrient cycling and population dynamics. Moreover, virophage-induced evolution between giant viruses and their hosts have also been described. Considering the ongoing discovery of virophages and their dynamics in aquatic ecosystems, this review intends to provide an update of the virophage signatures identified to date, also tending to provide insight on the mechanisms of coinfection as well as their role as agents of biodiversity and nutrient cyclers in water environments.     

Bioadsorption by sugarcane bagasse for the reduction in oil and grease content in aqueous effluent

Several techniques have been used to reduce the oil and grease content in aqueous streams; one excellent is bioadsorption. With a view to provide a sustainable method for the treatment of oily effluents, the aim of this study was to evaluate sugarcane bagasse as bioadsorbent to reduce the oil and grease content of aqueous effluents. Analysis of the material was performed, and the adsorption experiments were in a batch system, using a synthetic effluent. The results showed that the kinetic equilibrium occurred in 0.08 h of contact. The study of influence of pH of the aqueous phase and the temperature showed that the adsorption capacity was proportional to the pH value, but inversely proportional to the temperature. The adsorption isotherm was obtained at a temperature of 298.15 K using the Langmuir and Langmuir–Freundlich models, and the maximum adsorption capacity obtained was 6.65 kg of hydrocarbon per kg of bioadsorbent. It was verified that sugarcane bagasse represents an excellent material for application in the treatment of oily aqueous effluents, since it is associated with low cost and a high adsorption capacity. The variation in the adsorption capacity observed as a function of pH of the aqueous phase was not found to be significant. This is an important characteristic of the material in terms of its industrial application, verifying the possibility for its implementation in any treatment process, demonstrating the great potential of sugarcane bagasse for use as a sustainable alternative in the reduction in oil and grease in aqueous effluents.     

Prediction of ground vibration due to quarry blasting based on gene expression programming: a new model for peak particle velocity prediction

Blasting is a widely used technique for rock fragmentation in opencast mines and tunneling projects. Ground vibration is one of the most environmental effects produced by blasting operation. Therefore, the proper prediction of blast-induced ground vibrations is essential to identify safety area of blasting. This paper presents a predictive model based on gene expression programming (GEP) for estimating ground vibration produced by blasting operations conducted in a granite quarry, Malaysia. To achieve this aim, a total number of 102 blasting operations were investigated and relevant blasting parameters were measured. Furthermore, the most influential parameters on ground vibration, i.e., burden-to-spacing ratio, hole depth, stemming, powder factor, maximum charge per delay, and the distance from the blast face were considered and utilized to construct the GEP model. In order to show the capability of GEP model in estimating ground vibration, nonlinear multiple regression (NLMR) technique was also performed using the same datasets. The results demonstrated that the proposed model is able to predict blast-induced ground vibration more accurately than other developed technique. Coefficient of determination values of 0.914 and 0.874 for training and testing datasets of GEP model, respectively show superiority of this model in predicting ground vibration, while these values were obtained as 0.829 and 0.790 for NLMR model.