威海荣成鹿角菜野生种群遗传多样性及资源保护策略

利用随机扩增多态性DNA（RAPD）方法对威海荣成地区鹿角菜（Silvetiasiliquosa）野生种群共30个个体的遗传多样性水平及遗传结构进行研究。结果表明,利用21条随机引物共检测到112个多态性位点,多态性位点百分率为93．75％,Nei基因多样性指数为0．3515±0．1352,Shannon多样性指数为0．5046±0．1126。通过聚类分析而划为一类的3个亚种群间的遗传分化指数为0．1349～0．2189,基因流为1．7793。研究结果表明威海荣成地区的鹿角菜种群遗传多样性较高,种群内存在较为明显的遗传分化,种群遗传资源不受遗传漂变的影响。针对当地鹿角菜遗传资源的现状,应加强现存种群的就地保护,恢复种群规模;进行取样养殖保护时则需避免因近交而造成种群资源退化。     

Monitoring and environmental modeling of earthwork impacts: A road construction case study

This study presents the contributions of materials, earth engineering machines and construction techniques to potential environmental impacts from the main items of typical road earthworks. To achieve this goal, the overall activity at a 1.9-km long French earthworks project site for a heavily trafficked highway was surveyed during its 2007–2009 construction period. Using data collected and a numerical model of road life cycle assessment (LCA), i.e. ECORCE, six indicators could be evaluated, namely: energy consumption, global warming potential, acidification, eutrophication, photochemical ozone creation, and human chronic toxicity. When available, several life cycle inventories were implemented in order to appraise indicator sensitivity with respect to the considered panel of pollutants. Results also allowed estimating from an LCA point of view: (i) the conservation of both aggregates and soil as induced by quicklime treatment and (ii) the duration necessary for projected traffic levels to offset the potential environmental impacts of the earthworks stage.     

Bacterial diversity in activated sludge from a consecutively aerated submerged membrane bioreactor treating domestic wastewater

The bacterial diversity of activated sludge from submerged membrane bioreactor (SMBR) was investigated. A 16S rDNA clone library was generated, and 150 clones were screened using restriction fragment length polymorphism (RFLP). Of the screened clones, almost full-length 16S rDNA sequences of 64 clones were sequenced. Phylogenetic tree was constructed with a database containing clone sequences from this study and bacterial rDNA sequences from NCBI for identification purposes. The 90.6% of the clones were a?l...     

China’s Import of Wastes and Its Implications

Abstract

The trade of wastes in the world has been increasing and China has become the largest importer of wastes. This paper examines the import trend of different wastes and finds out that the total import volume to China approved by the Chinese government keeps increasing and the illegal trade can not be banned despite repeated prohibitions; therefore, China is not only “a world factory”, but actually “a global garbage dump”. In order to well understand the implications of wastes import, this paper further analyzes the resource and environmental effects and risks of different wastes imports as well as the strong driving force of wastes imports. Based on these detailed analysis and solid data, policy recommendations are put forward to reduce the demand for raw materials, to further strengthen the inspection of and supervision over the international trade of the wastes that can be used as raw materials by using the life cycle analysis and risk analysis, to improve the environmental standards and strengthen the disposal capacity, to re-export the raw materials produced from the imported wastes, to develop the long-term planning for the import of wastes and to promote international cooperation.     

Is a negative correlation between resource abundance and growth sufficient evidence that there is a “resource curse”?

Evidence from cross-sectional growth regressions suggests that economies dependent on natural resource exports have had slower growth than resource scarce economies. Explanations for this “curse of resources” focus on institutional and market failures caused by resource abundance. With a simple two sector model exhaustible resource model, we demonstrate that the correlation between growth and natural resource abundance can be negative in the absence of market and institutional failures. Since there is no way to distinguish between efficient and inefficient equilibria on the basis of the negative correlation between growth and resource abundance, finding that correlation is not sufficient to conclude resources are a curse, nor is it necessary to find a positive correlation between growth and resources to overturn the resource curse interpretation. We show whether resources are a curse or a blessing for an economy can only be determined by an investigation of the correlation between resource abundance and income levels. Using panel data for U.S. states for the period 1970-2001, we show that resource abundance is negatively correlated with growth rates but positively correlated with income levels.     

Location set covering for waste resource recycling centers in Taiwan

The efficiency of Taiwan's waste management and resource recycling systems has been well recognized in recent years, but the present model used to locate recycling centers and to assign collection depots to those centers continues to show low efficiency. To address this issue, the study herein suggests implementing a new location-planning and assignment model to reduce the number of existing recycling centers. Such a reduction would reduce the use of land resources. Moreover, the total transportation distance would decrease through the efficient assignment of collection depots to recycling centers. On the basis of results from previous studies, this study proposes a 2-stage location set covering problem-P-median integrated model that obtains exact solutions using heuristic algorithms on the basis of set operations. The results of numerical analyses show that the model introduced in this study is effective in solving the problems stated above as well as in improving the layout of Taiwan's existing recycling centers.     

Predicting future quantities of obsolete household appliances in Nanjing by a stock-based model

China has become one of the largest producers of obsolete household appliances (HAs) in the world. However, information on discarded HAs in China is deficient owing to the unavailability of reliable data. The estimation of future obsolete streams is a crucial issue for the establishment of efficient waste collection and recycling systems. The present study describes a prediction model to forecast future obsolete HAs on the basis of information of in-use stocks of HAs in households. The model was applied to a forecasting analysis of quantities of obsolete HAs from 2009 to 2050 in Nanjing, China. The results show that a total of about 76 million units (2.8 million tonnes) of obsolete HAs will be generated in Nanjing over the next 40 years. Discarded air conditioners, color TV sets, and personal computers will be the major contributors. The total discarded amount of major kinds of HAs will increase from nearly 1.0 million units in 2009 to a maximum of 2.1 million units in 2040, and then decrease slightly to 2.0 million units in 2050. Urban households will generate significantly more obsolete HAs (about 56 million units) than rural households, due to the difference in their HA possession levels. The results of this study should help the Nanjing municipality to develop the collection and recycling systems and facilities needed for the obsolete HAs generated in the future. From a methodological perspective, the stock-based model provides a suitable tool to predict the generation of discarded HAs in the future.     

水库水体热分层的水质及细菌群落分布特征

作为重要的城市饮用水源地,水库是人工筑坝形成的特殊类型的水体,其水质直接影响居民的饮用水安全.为揭示北京市饮用水源地密云水库的秋季分层特征和细菌群落的垂直变化,于水体稳定分层期(秋季)在水库进行采样,应用16S rDNA末端限制性片段长度多态性(T-RFLP)和定量PCR等方法研究了密云水库水体细菌群落的垂直分布特征,并利用聚类分析、多元统计分析揭示细菌群落与环境因子之间的响应关系.结果表明:(1)密云水库水体温跃层位于水深20～30 m处,水温范围在15～19℃,聚类分析将7个采样水层划分为好氧区(上层)和缺氧区(下层)两类,温度、DO、pH在15 m以下逐渐降低,电导率、氨氮、硝态氮、亚硝态氮及总氮在15 m后发生显著变化,水体水质表现出明显的垂直分布特征;(2)RDA分析结果显示,上下水层的溶解氧、pH、电导率、氨氮、硝态氮和亚硝态氮存在较为明显的垂向变化,是影响密云水库细菌群落垂直分布的主要环境因子;(3)总细菌的数量随水深变化的波动较为明显,其中好氧区细菌的Shannon-Wiener指数和T-RFs片段数明显高于缺氧区,说明秋季密云水库水体中细菌群落分布存在显著的分层现象.本研究探究了水体热分层对水库水质及细菌群落的影响,可为预测水质变化和水库管理提供科学依据.     

不同C/N值下亚硝酸盐氧化菌和异养菌混合体系的微生物多样性

采用PCR-RFLP技术研究了不同C/N比下亚硝酸盐氧化菌及异养菌混合体系的微牛物多样性,并探讨了微生物菌群结构与其功能(硝化件能)的关系.C/N=0时,混合体系主要由自养菌和寡营养菌(85.1%)组成,包括亚硝酸盐氧化菌(NOB)、拟杆菌门、α-变形菌纲、浮霉菌门和绿色非硫细菌中的一些菌株.C/N=0.44时,混合体系中的自养菌减少,异养菌(主要是γ-变形菌纲的成员)大量出现.C/N=8.82时,γ-变形菌纲的菌株尤其是反硝化菌Pseudomonas sp.占主导(93.8%),与此同时,随着C/N升高,该混合体系的硝化性能也由专一的亚硝酸盐氧化过程转变为同时硝化反硝化过程.微生物菌群结构的转变较好地解释了其硝化性能的改变.本研究揭示了微生物菌群结构与其功能的内在联系,同时表明PCR-RFLP技术与化学分析相结合是研究微生物菌群结构与功能的有力工具.图3表2参13     

Spatial and seasonal variations in bacterial communities of the Yellow Sea by T-RFLP analysis

Four typical coastal sites (rocky shore, sandy shore, mud flat shore, and artificial harbor) at the Yellow Sea were chosen to investigate the spatial and seasonal variations in bacterial communities. This was accomplished by using terminal restriction fragment length polymorphism (T-RFLP) analysis of PCR amplified 16S rDNA fragments. Two kinds of tetrameric restriction enzymes, HhaI and MspI, were used in the experiment to depict the bacterial community diversity in different marine environments. It was found that the community compositions digested by the two enzymes separately were different. However, the results of bacterial community diversity derived from them were similar. The MDA analysis results of T-RFLP profiles coming from HhaI and MspI both exhibited a significant seasonal community shift for bacteria and a relatively low spatial variation among the four locations. With HhaI as the sample, the pair wise T-tests also revealed that variations were minor between each pair of marine environments, with R ranging from 0.198 to 0.349. However, the bacterial community structure in the mud flat site depicted a larger difference than each of the other three sites (R ranging from 0.282 to 0.349).