河蚬（Corbicula fluminea）扰动对表层沉积物中氨氧化菌群落结构和丰度的影响

为研究不同生物量河蚬(Corbicula fluminea)的生物扰动对表层沉积物中氨氧化菌群落结构和丰度的影响,本研究设计了沉积物-水微宇宙的模拟体系,通过构建克隆文库、实时荧光定量PCR(real-time qPCR)等分子生物学方法比较不同密度河蚬扰动的沉积物中氨氧化古菌(ammonia-oxidizing archaea,AOA)和氨氧化细菌(ammonia-oxidizing bacteria,AOB)群落结构和丰度差异.结果表明,河蚬的生物扰动作用对表层沉积物氮素释放有明显的促进作用.氨氧化菌(AOA和AOB)amoA基因克隆文库中,AOA的amoA基因序列包含了已知的海洋和土壤环境中的两个分支,AOB的amoA基因绝大部分序列都属于变形菌门β亚纲(β-Proteobacteria)中的亚硝化单细胞菌属(Nitrosomonas).3个处理组表层沉积物中细菌amoA基因丰度均高于古菌amoA基因丰度,且河蚬密度越高则细菌amoA的丰度越低.同时,河蚬的添加使得微宇宙体系中氨氧化菌(AOA和AOB)的多样性降低.综上,河蚬的生物扰动对表层沉积物中氨氧化菌群落结构和丰度产生了一定的影响.     

Fenton氧化深度处理石化废水厂二级出水研究

采用连续流Fenton氧化对石化废水处理厂二级出水进行了处理试验,研究了药剂投量对COD及磷处理效果的影响,同时对处理过程中有机物的变化特性进行了分析.结果表明,原水COD平均为64.8 mg·L-1,PO3-4-P平均为0.79 mg·L-1,当H2O2(30%)投加量为0.4 m L·L-1,Fe SO4·7H2O的投加量为0.8 g·L-1,PAM投加量为0.9 mg·L-1,停留时间为30 min时,COD的平均去除率为24.3%,出水COD低于50 mg·L-1,PO3-4-P平均去除率为95.5%,原水中相对分子质量小于1×103的有机物占80.4%,Fenton氧化处理后该部分比例增加至95.6%.三维荧光分析结果表明,Fenton氧化对水中蛋白类、酚类去除效果显著.GC-MS结果表明,石化二级出水中检出主要有机物约117种,氧化后检出27种,含不饱和键类有机物去除明显.Fenton氧化可用于石化二级出水的深度处理.     

岩溶区地下水补给型水库表层无机碳时空变化特征及影响因素

为更深入地认识岩溶区地下水补给型水库表层无机碳的循环过程,于2014-07-12~2014-07-20期间,以广西上林县大龙洞岩溶水库表层水体为研究体系,对无机碳循环研究的重要指标进行定点观测和高密度的昼夜监测.结果发现:1从上游到下游DIC含量和水体p CO2值逐渐增加[DIC(平均):122.88 mg·L-1增至172.02 mg·L-1,p CO2(平均):637.91×10-6增至1 399.97×10-6],δ13CDIC值逐渐偏负[δ13CDIC(平均):-4.34‰降至-6.97‰].2库区均为大气CO2的源,CO2交换通量在7.11~335.54 mg·(m2·h)-1之间,平均125.03 mg·(m2·h)-1,上游和下游地区CO2交换通量较大[平均131.73 mg·(m2·h)-1、170.25 mg·(m2·h)-1],中游狭窄地区CO2交换通量较小[平均116.05 mg·(m2·h)-1].3表层水体p CO2值和水-气界面CO2交换通量存在晚上升高,白天降低的昼夜变化规律,且与叶绿素a(Chla)呈负相关关系.分析认为:1大龙洞水库表层水体DIC含量、δ13CDIC值和水体p CO2的空间分布主要受浮游植物浓度、浊度、电导率、水深、透明度等的影响,而水-气界面CO2交换通量除了受浮游植物浓度空间变化的影响外还受风速的影响.2浮游植物昼夜垂向运动及光合作用和呼吸作用昼夜变化控制着水库表层水体溶解性无机碳的昼夜循环过程.     

Distribution of Al-, Fe- and Mn-pools and their correlation in soils from two acid deposition small catchments in Hunan, China

Distribution of Al-, Fe- and Mn-pools was investigated in five forest soil profiles (consisting of four horizons) in each of two Hunan catchments (BLT and LKS) where acid deposition has been considered critical. Al- and Fe-pools were higher in BLT than those in LKS, but Mn-pools much lower in BLT. Mn-pools vary from topsoils to bottom soils, but there are different trends for different Mn speciation. Al- and Fe-pools, except amorphous Fe_ox, were positively correlated to contents of soil organic matter (OM) showed by the loss on ignition in the two catchments. Accumulation of Al- and Fe-pools may occur in the area where soil organic matter was enriched (e.g. in top soil and rhizosphere soil). However, no direct correlation is observed between Mn and OM. Acidic atmospheric deposition may affect transforming among speciations of Al-, Fe- and Mn-pools and leaching of soil Al, Fe and Mn through formation of soluble organo-metal dissolved Al which was potentially toxic, increased. There were significant correlations between Al-pools complexes or change of oxidation–reduction conditions. Mn_ex (exchangeable Mn) and Mn_ox (amorphous and organic Mn) were highly linearly correlation with soil pH values at LKS but at BLT. Under acid deposition, the availability of the nutrient Fe increased with the amount of dissolved Al, which was potentially toxic, in the two catchments. There are no significant correlations between Al_ex (exchangeable Al) and Mn_ex, Fe_ex (exchangeable Fe) and Mn_ex in this work, indicating potentially toxic Mn increase seldom accompanying with Al increase in the two catchments.     

A survey of radon level in underground buildings in China

From 2003-2004, using solid state nuclear detectors, a survey of the air radon level in 234 underground buildings in 23 cities of China was carried out during spring as well as summer and winter. The annual radon concentrations in these underground buildings range from 14.9 to 2482 Bq m(-3), with an overall mean value of 247 Bqm(-3). When radon concentrations are averaged according to cities, Fuzhou and Baotou have the relatively higher radon levels, which are 714 and 705 Bqm(-3), respectively. Guangzhou and Shanghai have the relatively lower radon levels with 71.1 and 72.6 Bqm(-3). The annual effective dose by exposure to radon received by people working in these cities is concluded to be 1.6 mSv. The geological formation, coating level, decorating materials and ventilation situation all affect the radon concentration in underground buildings. The radon level in underground buildings has the lowest value in winter and the highest value in summer.     

剑湖流域土壤/沉积物重金属分布特征、来源解析及生态风险

以剑湖流域为研究对象,通过系统采集流域内陆地土壤、河流和湖泊沉积物样品,利用电感耦合等离子体发射光谱仪(ICP-OES)测定72个采样点镉(Cd)、铬(Cr)、铜(Cu)、铅(Pb)、钒(V)和锌(Zn)等6种重金属含量,分析流域重金属分布特征,利用单因子污染指数法和内梅罗综合污染指数法、地累积指数法评估其污染程度,利...     

继承与创新:近30年来中国近代灾荒史研究概述——环境社会学的思考

中国近代灾荒史再研究起步于20世纪80年代。文章从整体性研究、区域灾荒史研究、专题性研究和史料整理建设工作等四个方面简要回顾了近30年来该领域所取得的丰硕成果。在此基础上,指出目前存在的问题和不足,并重点从环境社会学角度提出中国近代灾荒史研究今后在研究理论和方法、研究领域和内容、资料建设以及研究队伍等4个方面的努力方向,希冀为中国近代灾荒史研究在宏观把握和向纵深发展两方面有序并进提供些许思路和参考。     

数字电视图像硬盘录像

本文从数字图像的特点引出图像讯号压缩技术,并介绍了不同压缩方式的特点及其最佳使用场合.同时引入统计概念来估算数字硬盘录像单位时间所需的平均容量和评估图像质量,为合理正确选用何种数字硬盘录像设备和选用何种工作方式提出了一些有益的看法.     

Development of Future Generations： Oriented Virtual Negotiation Support System for Intergenerational Conflict

Intergenerational conflict coordination is the fundamental requirement and core of sustainable development. In this paper, through the analysis of the future generations-oriented management mechanisms for intergenerational conflict, the idea of mechanisms and institution building for the coordination and management of intergenerational conflict is put forward. Furthermore, the future generations-oriented virtual negotiation support system （NSS） for intergenerational conflict is developed, built on the analysis of the process simulation of intergenerational wealth transfer, intergenerational equilibrium allocation of resources, and strategies for the mitigation and avoidance of intergenerational conflict, through the application of advanced IT technology. The virtual NSS for intergenerational conflict is helpful to the practical application of the sustainable development theory; on the other hand, it can be applied directly to the intergenerational equilibrium allocation of resources, national economic accounting, formulation of sustainable development strategies and other urgent national economic and social development issues. Finally, the sustainable development theory can be enriched and extended. Therefore, the development of the future generations-oriented virtual NSS for intergenerational conflict has certain theoretical and practical effects on the theory of sustainable development.     

Organochlorine pesticides and polychlorinated biphenyls in Tibetan forest soil: profile distribution and processes

Tibetan forests are located in the southeastern Tibetan Plateau, where the climate is dominated by the Indian monsoon. Due to the affinity to pollution sources and high organic carbon stocks, the fate of persistent organic pollutants in the Tibetan forests should be given more attention. In this study, seven soil profiles were investigated to obtain the vertical distribution of the organochlorine pesticides and polychlorinated biphenyls (PCBs) in the Tibetan forest soil. The results indicate that the DDTs are highly stable in the soil, with limited volatilization and leaching, while the more volatile PCBs were found in the deeper mineral layer, which means that they can translocate through the organic layer and move farther downward into the deep soil. The air-to-ground fluxes (estimated by the age of the organic layer) of the DDTs are one magnitude higher than those reported in a study on the Alps, suggesting the higher accumulation of DDTs by the Tibetan forest.