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951.
为研究海拔变化和退化过程中高寒草甸土壤细菌群落多样性的变化规律,利用MiSeq高通量测序技术,分析不同海拔活动斑块、非活动斑块、恢复斑块和高寒草甸土壤细菌群落多样性,利用冗余分析对细菌多样性和环境因子进行分析.结果发现,3种类型斑块中主要的土壤细菌门均是变形菌门(Proteobacteria)、放线菌门(Actinobacteriota)和酸杆菌门(Acidobacteriota).细菌优势属为RB 41 、鞘脂单胞菌属(Sphingomonas)和慢生根瘤菌属(Bradyrhizobium).RB 41 和慢生根瘤菌属相对丰度随海拔升高而下降,随斑块演替而增加,但3种类型退化斑块相对丰度均显著低于高寒草甸(P<0.05).退化斑块土壤碳固定功能的细菌丰度,大于健康高寒草甸.不同斑块的细菌Chao1指数和物种数显著高于高寒草甸(P<0.05).冗余分析发现,生物结皮盖度和全氮是海拔4013 m处细菌优势门的主要影响因子;生物量、全氮和pH对高海拔4224 m细菌优势门影响较大.生物量和全钾显著影响海拔4013 m的细菌属分布,海拔4224 m地区莎草科盖度和速效氮为细菌优势属的主要影响因子.生物结皮和pH对细菌多样性影响较大.不同海拔地区细菌的影响因子发生着较大变化,在研究细菌多样性变化的过程中,不仅要关注高寒草地退化的影响,还应考虑海拔高度的作用. 相似文献
952.
废水排放对近海环境中抗生素抗性基因和微生物群落的影响 总被引:1,自引:0,他引:1
污水处理厂是水环境中抗生素抗性基因(ARGs)的重要来源.可移动遗传元件(MGEs)和微生物群落是影响ARGs增殖扩散的关键因素.为探究污水处理厂废水排放对近海环境中ARGs和微生物群落的影响,采用高通量荧光定量PCR (HT-qPCR)和高通量16S rRNA扩增子测序技术,对杭州湾上虞(SY)和嘉兴(JX)两个近岸纳污区(ERAs)及远岸湾区表层沉积物中ARGs、MGEs和微生物群落的组成和分布进行调查.结果表明,多重耐药类ARGs是所有样点中丰度最高的ARGs类型.纳污区沉积物中ARGs和MGEs多样性和丰度远远高于远岸湾区沉积物.JX纳污区沉积物中微生物群落丰富度和多样性高于SY纳污区及远岸湾区沉积物.PCoA结果显示,纳污区与远岸湾区沉积物中ARGs、MGEs和微生物群落分布存在显著的差异,说明长期的废水排放对近海环境中ARGs、MGEs和微生物群落影响较大.ARGs、MGEs和细菌属的共现网络显示,嗜冷杆菌属、假单胞菌属、亚硫酸杆菌属、假交替单胞菌属和芽孢杆菌属等12种菌属与ARGs和MGEs存在显著正相关.多重耐药类和β-内酰胺类ARGs的潜在宿主最多. 相似文献
953.
Robin Hickman Patricia Austin David Banister 《Journal of Environmental Policy & Planning》2014,16(3):419-435
AbstractA number of cities around the world are associated with very high levels of private motor car usage, and Auckland provides an example of one of these ‘hyperautomobile’ cities. There are many problems with this system of transportation and dependence on the private car, including environmental, social and city design dimensions. Though there is a clear aspiration to move towards reduced levels of car usage in the city's transport and spatial planning strategies, there are major difficulties in implementation terms. We develop and consider future scenarios to 2041 to reduce these levels of motorization, and subsequent transport CO2 emissions, with a much greater use of public transport, walking and cycling, urban planning, and low emission vehicles. The current implementability of such a ‘sustainable mobility’ future is however questioned in the current political and social context, and critically debated in terms of the available governance mechanisms and the limited attempts to shape the behaviour of the public. We conclude by calling for a reconsideration of the policy measures being considered, including the range and levels of application and investment; with a much wider framing of the transport planning remit, and carried out within a much stronger participatory framework for decision-making. 相似文献
954.
Singapore has pledged to attain 7–11% Business-As-Usual carbon emissions reduction by 2020. About 19% of CO2 contribution stemmed from road transport in 2005. Commercial vehicles, which uses mainly diesel, consumed 695 million litres diesel in 2012. An estimated 115,585 tonnes or 127 million litres cooking oils (derived from seeds/fruits) were consumed in 2010, in which the bulk of used cooking oil is re-incorporated into the food preparation process while only a small amount is being recycled into biodiesel or disposed into the sewerage. Nevertheless, the present research reveals that biodiesel derived from spent cooking oil has potential to be a viable fuel supplement. Surveys were carried out involving three market segments – suppliers, processors and end-users – to identify the barriers and obstacles in mass production of biodiesel. A key enabler of biodiesel as a fuel supplement towards a greener environment lies in government mandate/policies in promoting greater biodiesel usage. 相似文献
955.
In policy support of municipal solid waste (MSW) management, life cycle assessment (LCA) can serve to compare the environmental or economic impacts of two or more options for waste processing. The scope of waste management LCAs generally focuses less attention on future developments, e.g., where will recycling take place, and more on the environmental performance of prototypes, e.g., the incineration of all waste compared to recycling. To provide more robust support for Swiss waste glass-packaging disposal, scenarios of Swiss waste glass-packaging are assessed from a life cycle perspective. The scenarios consist in schemes for the disposal of the total amount of Swiss waste glass-packaging, i.e., different combinations of recycling and downcycling in Switzerland or abroad developed in Part I, Meylan et al. (2013). In this article (Part II), the disposal schemes are assessed with respect to eco-efficiency, an indicator that combines total environmental impacts and gross value added in Switzerland. Results show that no policy alternative guarantees environmental impact reductions and gross value added gains under all developments of exogenous constraints. Downcycling to foam glass in Switzerland is not only an environmentally sound disposal option, but it also buffers gross value added losses in case domestic recycling (and thus glass-packaging production in Switzerland) ceases in the future. The substitution of products based on raw materials other than Swiss cullet is the main responsible for change in environmental and economic impacts. Hence, an eco-efficiency maximizing policy should consider the products of disposal schemes. The combination of scenario analysis and eco-efficiency assessment as presented in this paper can be applied to other contexts (i.e., countries, waste fractions). 相似文献
956.
Recycling End of Life (EOL) concrete into high-grade aggregate for new concrete is a challenging prospect for the building sector because of the competing constraints of low recycling process cost and high aggregate product quality. A further complicating factor is that, from the perspective of the environment, there is a strong societal drive to reduce bulk transport of building materials in urban environments, and to apply more in situ recycling technologies for Construction & Demolition Waste. The European C2CA project investigates a combination of smart demolition, grinding of the crushed concrete in an autogenous mill to increase the liberation of cement mortar from the surface of aggregates and a novel dry classification technology called ADR to remove the fines. The feasibility of this recycling process was examined in a demonstration project involving 20,000 tons of EOL concrete from two office towers in Groningen, the Netherlands. Results show that the +4 mm recycled aggregate compares favorably with natural aggregate in terms of workability and the compressive strength of the new concrete, showing 30% higher strength after 7 days. 相似文献
957.
958.
959.
The amount of used lead acid batteries rises along with the rapid development of battery manufacture in China. The battery manufacture and recycling industry has developed sharply in these recent 5 years. The annual production of secondary lead from used lead acid batteries in China increased rapidly to 1.5 million tonnes (MT) in 2013, making china the world's largest secondary lead producer. Secondary lead enterprises are mainly located in the middle and eastern regions of China, with a legal production capacity of 3 MT/year. Environmental pollution problems began to happen frequently from 2009. After 2011, the government began to put in efforts to promote pollution control, eliminate outdated production capacity, support advanced production and technology innovation research, and has achieved remarkable results. However, the main existing problems are that the proportion of secondary lead production is only 30% of the total lead production, no formal recycling network has been established and the overall level of industrial technology and equipment is outdated. Compared with developed countries, this paper predicts that, secondary proportion will reach 44% in 2015 and 60% in 2028. Finally some countermeasures are given to the recycling mode and technology promotion. 相似文献
960.