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31.
We examined the effects of crude oil contamination on community assemblages of meiofauna and nematodes after exposure to total petroleum hydrocarbons in the laboratory. We administered a seawater solution that had been contaminated with total petroleum hydrocarbons to seven treatment groups at different concentrations, while the control group received uncontaminated filtered seawater. The average density of total meiofauna in the experimental microcosms diluted with 0.5%, 1%, 2%, and 4% contaminated seawater was higher than the density in the control. The average density of total meiofauna in the 8%, 15%, and 20% microcosms was lower than the density in the control. The density of nematodes was similar to that of the total meiofauna. Cluster analysis divided the microcosms into group 1 (control, 0.5%, 1%, 2%, and 4% microcosms) and group 2 (8%, 15%, and 20% microcosms). However, SIMPROF analysis showed no significant difference between the two groups (p > 0.05). Bolbolaimus spp. (37.1%) were dominant among the nematodes. Cluster analysis showed similar results for nematode and meiofaunal communities. The total meiofaunal density, nematode density, and number of Bolbolaimus spp. individuals were significantly negatively associated with the concentration of total petroleum hydrocarbons (Spearman correlation coefficients, p < 0.05). Within the nematodes, epistrate feeders (group 2A: 46%) were the most abundant trophic group. Among the treatment groups, the abundance of group 2A increased in low-concentration microcosms and decreased in high-concentration microcosms. Thus, our findings provide information on the effects of oil pollution on meiofauna in the intertidal zones of sandy beaches.  相似文献   
32.
粤东深澳湾养殖区域异养细菌和弧菌的动态分布   总被引:1,自引:0,他引:1  
调查于2007年1月至2008年12月进行,对异养细菌和弧菌丰度的时间和空间分布开展了相关的研究,结果显示深澳养殖海湾水体中以上2种被调查菌类的丰度全年变化范围分别为1.20×105―1.27×108cfu·L-1和1.00×103―3.90×105cfu·L-1;底质中的丰度变化范围分别为2.73×104―4.06×107cfu·g-1和3.25×102―7.23×104cfu·g-1.从时间上来看,营养盐类与异养细菌的相关性要强于温度、盐度、pH值和溶氧等物理因素的相关性;而弧菌与物理因素的相关性要强于与营养盐类的相关性.从空间分布来看水体环境的变化要比底质的大,水体中经常出现异养细菌和弧菌丰度的剧烈变化,变化程度也远远高于底质中细菌的变化.而且不同的养殖活动也会很明显地影响异养细菌和弧菌的丰度:S3站位水体中异养细菌的丰度比底质中的高;S5站位的底质中异养细菌和弧菌的丰度都是较高的.龙须菜的养殖可以很明显地改善底质环境,特别是降低底质中对养殖和水质环境有很大负面影响的生物和非生物因子如硫化物和弧菌等.  相似文献   
33.
Based on monitored data from 840 samples, we assessed the spatial and temporal variability of groundwater salinization in the Tarim River lower reaches combining classical statistics and geostatistics. Results show that total dissolved solids (TDS) is significantly correlated with other related ions, such as Na+, Mg2+, Ca2-, C1- and K+. TDS and underground water level have characteristics of spatial autocorrelation, both of which present the isotropic characteristic and con- form to the spherical model in each year from 2001-2009. TDS is basically greater than 1 g/L but less than 2 g/L in the Tarim River lower reaches, which indicates that salt stagnation pollution is more serious. The most serious salinization (3 g/L 〈 TDS _〈 35 g/L) contaminated area is mainly in the middle and lower part of the study area.  相似文献   
34.
鉴于当前遥感图像矢量化效率普遍不高,提出了一种遥感聚合图像的快速拓扑矢量化方法。该方法对聚合图像中的聚合对象进行唯一性标号,并将这个标号作为属性赋予生成的矢量多边形,通过矢量多边形的标号间映射关系便可以快速建立复杂岛屿多边形的拓扑包含关系。试验表明,该方法能够精确地完成斑块对象边界追踪及复杂岛屿多边形处理,并显著提高矢量化的速度。  相似文献   
35.
GeoJournal - Two phases of study are involved in this research: first, the sales strategies for affordable houses embedded with eco-friendly and smart technology features; and second, the impact of...  相似文献   
36.
Simplified techniques based on in situ testing methods are commonly used to predict liquefaction potential. Many of these simplified methods are based on finding the liquefaction boundary separating two categories (the occurrence or non-occurrence of liquefaction) through the analysis of liquefaction case histories. As the liquefaction classification problem is highly nonlinear in nature, it is difficult to develop a comprehensive model taking into account all the independent variables, such as the seismic and soil properties, using conventional modeling techniques. Hence, in many of the conventional methods that have been proposed, simplified assumptions have been made. In this study, an updated support vector machine (SVM) based on particle swarm optimization (PSO) is used to evaluate liquefaction potential in two separate case studies. One case is based on standard penetration test (SPT) data and the other is based on cone penetration test (CPT) data. The SVM model effectively explores the relationship between the independent and dependent variables without any assumptions about the relationship between the various variables. This study serves to demonstrate that the SVM can “discover” the intrinsic relationship between the seismic and soil parameters and the liquefaction potential. Comparisons indicate that the SVM models perform far better than the conventional methods in predicting the occurrence or non-occurrence of liquefaction.  相似文献   
37.
People living in the urban area and the surrounding suburban area have disparities in exposure and health risks due to different levels of ambient air pollutants. The main objective of this study is to investigate the concentrations, seasonal variations, and related health risks of ambient air pollutants (PM10, NO2, and SO2) in urban and suburban areas of Ningbo, China. The results showed that the average PM10, NO2, and SO2 concentrations in the urban area were 85.2, 49.3, and 37.4 μg/m3, which were 1.13, 1.25, and 1.41 times the values of the suburban area during the period of March 2009 to February 2010. For the potential health risk analysis, the residents have been divided into four age categories namely, infants, children (1 year), children (8–10 years), and adults. The analysis took into account age-specific breathing rates, body weights for different age categories. The results showed that the potential health risks to respiratory disease for all age categories living in urban area were higher than those in suburban area.  相似文献   
38.
旨在分析城市不动产登记的服务效率及影响因素,为机构整治提供针对性建议。界定了以公众满意度为效率测度,以拥挤程度、等待时长、程序繁度和办理方式等为指标的外部评价框架;设计了公众舆情的网络采集和服务效率指标计算及特征分析方法。对2015年3月至2017年9月间,涉及25个省区的108个城市的479条不动产登记相关网络新闻分析可知,北京、上海、青岛等城市在拥挤程度、等待时长方面的舆情指数较高,需要利用互联网拓展增加登记办理入口以减缓供需矛盾;程序繁琐和办理方式复杂是影响郑州、石家庄、广州等城市不动产登记效率评价的主要因素,应优化登记流程、改进平台技术;城市等级规模、房地产调控政策影响舆情指数,城市不动产登记机构应做好与之配套的应急措施。  相似文献   
39.
甘肃巴谢剖面黄土-古土壤的光释光测年研究   总被引:2,自引:0,他引:2  
光释光(OSL)测年是测定第四纪沉积物年龄的一种新技术。它通过单色光束激发使晶体中储存的电离辐射能释放出来。与热释光(TL)测年相比,OSL测年可以不考虑残留的OSL信号,而且测量具有简便、迅速且准确等优点。本文用细颗粒光释光技术对甘肃巴谢剖面的黄土-古土壤进行了测定,其测年结果与14C测年结果相吻合。这表明,光释光是一项极潜力的年代学技术。  相似文献   
40.
采用染色薄片鉴定、阴极发光显微镜观察、微量元素分析、碳氧稳定同位素测定及包体侧温等手段,对塔里木盆地巴楚断隆区寒武系和奥陶系白云岩的特征及成因进行了研究,共划分出四种类型的白云岩:①泥粉晶白云岩,其m(Ca)/m(Mg)平均为3-10,Sr含量高(>300×10-6 ),m(Sr)/m(Ba)>>1,?13C值较高(-1‰-+1‰),18O值较低(-5‰--8‰),沉积环境为潮上带云坪,为准同生作用阶段潮上萨布哈白云化作用形成。②含雾心亮边白云石的细晶白云岩,其m(Ca)/m(Mg)较低(1-2),Sr含量中等(100×10-6-200×10-6),m(Sr)/m(Ba) >1,?13C值在-2‰左右,18O值低,在-7‰左右,沉积环境为开阔台地浅滩,为准同生或早期成岩作用阶段回流渗透白云化作用形成。③含明亮白云石晶体及钙质残余的钙质白云岩,其m(Ca)/m(Mg)较低(1左右),Sr含量最低(100×10-6左右),m(Sr)/m(Ba) < 1,?13C值最低(-1‰--3‰),?18O值较低(-6‰左右),沉积环境为灰坪、云坪及开阔台地,为准同生或早期成岩作用阶段混合水白云化作用形成。④砂糖状白云岩,其m(Ca)/m(Mg)较低(1-2),Sr含量低(<100×10-6),m(Sr)/m(Ba)<1,?13C值较高(-1‰-+3‰),18O值较低(-5‰--8‰),沉积环境多为浅滩,为晚期成岩作用阶段埋藏白云化作用形成。  相似文献   
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