Marine bacterium strain screening and pyrethroid insecticide-degrading efficiency analysis     

孙爱丽  刘菁华  史西志  李德祥  陈炯  唐道军 《中国海洋湖沼学报》2014,32(5):1029-1035

A pyrethroid insecticide-degrading bacterium, strain HS-24, was isolated from an offshore seawater environment. The strain, which can degrade cypermethrin(CYP) and deltamethrin(DEL), was identified as Methylophaga sp. The optimal culture and degradation conditions for CYP and DEL by strain HS-24 is pH 7 at 28°C. Under optimum culture conditions, strain HS-24 exhibited a broad degradation concentration range of 100, 200, 400, 600, and 800 mg/L for CYP and DEL. The metabolic intermediates were analyzed by NMR, which provided strong evidence that CYP and DEL removal occurred mainly because of a biological process. The toxicity of the degradation products of strain HS-24 was studied simultaneously by measuring the light output of the luminescence bacterium. This demonstrated that the biodegradation ability of strain HS-24 significantly decreased the toxicity of CYP- and DEL-contaminated aquaculture seawater. Finally, the findings of this paper indicate that strain HS-24 is thus revealed as a biological agent for the remediation of marine aquatic environments.  相似文献   

基于指标规范值的海水水质评价的SVR模型   总被引：1，自引：0，他引：1  

梁晓龙  李祚泳  汪嘉杨 《成都信息工程学院学报》2014,(2):208-212

为了建立具有普适通用的海水水质评价的支持向量机模型,在设置各指标参照值和指标规范变换式,并对指标进行规范变换的基础上,应用免疫进化优化算法,建立基于指标规范值的海水水质评价的回归支持向量机模型。将优化好的模型用于珠江口海水水质的评价,其评价结果与BP神经网络的评价结果基本一致,从而表明基于指标规范值的支持向量机模型用于海水水质评价是可行的,且该模型较传统的支持向量机评价模型具有较好的普适性和通用性。  相似文献   

Research on the critical conditions for clay particle release during saline aquifer freshening process     

Xilai Zheng  Ran Chen 《中国海洋大学学报(英文版)》2014,13(4):628-636

Water sensitivity phenomenon occurs during saline aquifer freshening process in seawater intrusion area, and clay particles released in the phenomenon can damage the infiltration capacity of the aquifer. In order to find out the factors and mechanisms for clay particle release, laboratory column infiltration experiments simulating saline aquifer freshening process were designed to measure the critical conditions(critical flow velocity, critical salt concentration and critical ionic strength) and force analysis for clay particle according to DLVO electric double layer theory was employed to illustrate the mechanisms for particle release. The research results showed that critical flow velocity for clay particle release is influenced by salt concentration of injecting solution. When salt concentration of injecting solution is very high, clay particles are not released, indicating that there does not exist a critical flow velocity in this situation. As salt concentration of injecting solution decreases, particles start to be released. The critical salt concentration for clay particle release is 0.052 mol L-1 in our work, which was determined by a constant-flux experiment for stepwise displacement of high concentration Na Cl solution. The critical ionic strength for clay particle release decreases as Ca2+ molar content percentage of the mixed solution of Na Cl and Ca Cl2 increases following the first-order exponential decay equation y = 0.0391e-0.266 x + 0.0015.  相似文献   

Molecularly imprinted polymers for selective extraction of crystal violet from natural seawater coupled with high-performance liquid chromatographic determination     

LIAN Ziru  and WANG Jiangtao 《中国海洋大学学报(英文版)》2014,13(2):236-242

Molecularly imprinted polymers(MIPs) were prepared by the bulk polymerization using crystal violet as the template molecule, and the methacrylic acid and ethylene glycol dimetheacrylate as functional monomer and cross-linker, respectively. Systematic investigations of synthetic conditions were conducted. The surface morphology and recognition mechanism of the obtained polymers were studied using scanning electron microscope and spectrophotometric analysis. MIPs showed high affinity to template molecule and were successfully applied as special solid-phase extraction sorbent for selective extraction of crystal violet from natural seawater. An off-line molecularly imprinted solid-phase extraction(MISPE) method followed by high-performance liquid chromatography with diodearray detection for the analysis of crystal violet was also established. MISPE columns have good recoveries for crystal violet standard solutions and good linearity was obtained over the concentration range of 0-200 μg L-1(R2 0.99). Finally, two natural seawater samples were investigated. The recoveries of spiked seawater on the MISPE columns were from 44.47% to 62.34%, the relative standard deviation(n=3) being in the range of 2.89%-5.96%.  相似文献   

基于非均匀水体对比度传输方程的海水透明度计算试验          下载免费PDF全文

李妍  陈希  于斌  钟奕飞 《大气科学学报》2014,37(6):767-771

针对均匀水体假设的海水透明度经验计算公式不具有普适性的缺点,将海水在垂直方向上分为若干光学性质相近的均匀层,推导出非均匀水体中目标对比度传输方程,在此基础上,建立了海水透明度的计算模型。利用BROKE_WEST_ACS实测的海水固有光学性质数据和透明度盘观测数据,对计算模型进行了数值试验和效果分析。结果表明:模型计算值与透明度盘实测值平均相对误差为9.1%;该模型既克服了透明度盘测量易受天气状况和人眼差异影响较大的缺点,又突破了均匀水体透明度计算方法的局限性。  相似文献   

Calcium,Na, K and Mg Concentrations in Seawater by Inductively Coupled Plasma‐Atomic Emission Spectrometry: Applications to IAPSO Seawater Reference Material,Hydrothermal Fluids and Synthetic Seawater Solutions     

Philippe Besson  Jefferson Degboe  Benjamin Berge  Valérie Chavagnac  Sébastien Fabre  Gilles Berger 《Geostandards and Geoanalytical Research》2014,38(3):355-362

We report a measurement procedure to determine simultaneously the major cation concentrations (Na, Ca, K and Mg) of seawater‐derived solutions by inductively coupled plasma‐atomic emission spectrometry. The best results were obtained when the IAPSO (‘standard’) seawater reference material was diluted by thirty times with Milli‐Q^® water. We obtained an average reference value r_K (the ratio of the mass fraction of potassium to that of chlorine, i.e., (g kg^?1)/(g kg^?1)) for IAPSO seawater of 0.0205 ± 0.0006 (2.9% RSD), not significantly different from 0.0206 ± 0.0005 (2.4% RSD) for seawater composition reported in the literature. The measured Na, Ca and Mg concentrations correspond to r_Na, r_Ca and r_Mg values of 0.5406 ± 0.0026 (0.5% RSD), 0.02192 ± 0.00048 (2.2% RSD) and 0.06830 ± 0.00047 (0.7% RSD), respectively, in line with previous values measured by wet‐chemistry and atomic absorption spectrophotometry or wet‐chemical titration. Our measurement procedure was used successfully on synthetic seawater solutions and high‐temperature hydrothermal fluids.  相似文献   

Emplacement of the La Peña alkaline igneous complex,Mendoza, Argentina (33° S): Implications for the early Miocene tectonic regime in the retroarc of the Andes     

《Journal of South American Earth Sciences》2014

The La Peña alkaline complex (LPC) of Miocene age (18–19 Ma) lies on the eastern front of the Precordillera (32°41ʹ34ʺS, 68°59ʹ48″W, 1400–2900 m a.s.l.), 30 km northwest of Mendoza city, Argentina. It is a subcircular massif of 19 km² and 5 km in diameter, intruded in the metasedimentary sequence of the Villavicencio Formation of Silurian-Devonian age. It is the result of integration of multiple pulses derived from one or more deep magma chambers, which form a suite of silicate rocks grouped into: a clinopyroxenite body, a central syenite facies with a large breccia zone at the contact with the clinopyroxenite, bodies of malignite, trachyte and syenite porphyry necks, and a system of radial and annular dikes of different compositions. Its subcircular geometry and dike system distribution are frequent features of intraplate plutons or plutons emplaced in post-orogenic settings. These morphostructural features characterize numerous alkaline complexes worldwide and denote the importance of magmatic pressures that cause doming with radial and annular fracturing, in a brittle country rock. However, in the LPC, the attitude of the internal fabric of plutonic and subvolcanic units and the preferential layout of dikes match the NW–SE extensional fractures widely distributed in the host rock. This feature indicates a strong tectonic control linked to the structure that facilitate space for emplacement, corresponding to the brittle shear zone parallel to the N–S stratigraphy of the country rock. Shearing produced a system of discontinuities, with a K fractal fracture pattern, given by the combination of Riedel (R), anti-Riedel (R′), (P) and extensional (T) fracture systems, responsible for the control of melt migration by the opening of various fracture branches, but particularly through the NW–SE (T) fractures. Five different pulses would have ascent, (1) an initial one from which cumulate clinopyroxenite was formed, (2) a phase of mafic composition represented by dikes cross-cutting the clinopyroxenite, (3) a malignite facies that causes a small breccia in the clinopyroxenite, (4) a central syenite facies that develops breccias at the contact with the clinopyroxenite and, finally, (5) porphyry necks and a system of radial dikes intruding all units. At the moment of the emplacement different mechanisms would have acted, they summarized in: 1) opening of discontinuities synchronous to the magma circulation as the principal mechanism for formation of dikes and conduits; 2) stoping processes, that play an important role in the development of the breccia zone and enabling an efficient transference of material during the emplacement of the syenitic magma and 3) shear-related deformation (regional stress), affected the internal fabric of the facies, causing intracrystalline deformation and submagmatic flow, which is very evident in the central syenite intrusive. The kinematic analysis of shear planes allows proposing that emplacement of the LPC took place in a transtensive regime, which would have occurred in the back-arc of the Andes orogen, during a long period spanning from Miocene to the present, of the compressive deformation responsible, westward and at the same latitude, for the development of the Aconcagua fold and thrust belt.  相似文献   

特色保护类村域农村居民点空间重构探析   总被引：1，自引：0，他引：1  

冯德东  冯应斌  赵玲珑  龙花楼  徐雨利 《地理科学进展》2022,41(5):825-837

快速城镇化进程中中国乡村聚落空间面临剧烈分化和重组,农村居民点空间重构有利于乡村转型发展。论文基于系统理论,梳理了特色村落农村居民点空间系统形成机制,提出“遵循有序性—延续精神性—落脚物质性”的重构框架,并以贵州省江口县坝梅村为例,选用规模指数、基因分析及空间分析等方法解译了村域居民点系统内、外部特征,提出重构模式。研究表明：① 行为主体、文化基因及民居建筑构成坝梅村居民点内部系统,并分别呈“多元主体行为诱发空间变化、文化基因丰富但延续较差、用地结构与功能多样化”的特征;② 坝梅村居民点系统外部特征体现在外部环境对居民点起约束和导向作用,表现为距离点状、线状基础设施及河流越近,村域居民点数量、规模越大;③ 基于特征认知和重构框架,按照“分区—分类”方法,划分了核心区、重点区、提升区和保育区4种治理区以及完好型、受损型、缺失型、失真型4类民居提升类型,并提出了自组织和他组织2种模式下的居民点空间重构策略,为推动特色村落空间治理与转型提供参考。  相似文献   

The impact of highly permeable layer on hydraulic system in a coastal aquifer     

Kue‐Young Kim  Weon Shik Han  Eungyu Park 《水文研究》2013,27(22):3128-3138

This study is aimed to understand the hydraulic mechanism of coastal aquifer systems that include highly permeable layers (HPLs). These hydrologic conditions can be found in many volcanic islands that are composed of a series of lava flows discharged into sea or other standing body of water. In the first part, we developed a numerical model based on the geologic and hydrologic data obtained from the eastern Jeju Island, Korea, of which the aquifer contains clinker and hyaloclastite layers. The simulation results reproduced spatial location of fresh‐saline water interface, especially the abrupt decline of interface at the inland part and the thickness variation of transition zone along the cross‐section observed at the eastern Jeju coastal aquifer. We were able to find out that these phenomena are strongly related to the presence of the HPL. In the second part, quantitative analyses were conducted with the use of hypothetical models in order to understand the dynamic characteristics of coastal system that includes HPLs. A series of sensitivity studies were conducted to assess the effect of the horizontal length and vertical depth of HPL on the spatial location of the interface toe and the configuration of transition zone. Various case studies have shown that the seawater intruded into the inland more as the horizontal length of HPL was increased and its vertical depth was decreased. In other simulations including two HPLs, the vertical distance between these two HPLs primarily controlled the flow regime, flux variations, and the configuration of the transition zone. Finally, we performed simulations to evaluate the effect of a rising sea‐level. This study provides more understanding of how the presence of HPL controls the seawater intrusion processes, and the spatial configurations of fresh‐saline water interface at coastal aquifers. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Comprehensive Assessment of Seawater Quality on an Improved Attribute Recognition Model     

ZHANG Libing CHENG Jilin JIN Juliang JIANG Xiaohong 《中国海洋大学学报(英文版)》2006,5(4):300-304

The attribute recognition model （ARM） has been widely used to make comprehensive assessment in many engineering fields, such as environment, ecology, and economy. However, large numbers of experiments indicate that the value of weight vector has no relativity to its initial value but depends on the data of Quality Standard and actual samples. In the present study, the ARM is enhanced with the technique of data driving, which means some more groups of data from the Quality Standard are selected with the uniform random method to make the calculation of weight values more rational and more scientific. This improved attribute recognition model （IARM） is applied to a real case of assessment on seawater quality. The given example shows that the IARM has the merits of being simple in principle, easy to operate, and capable of producing objective results, and is therefore of use in evaluation problems in marine environment science.  相似文献