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991.
Marrs RH Galtress K Tong C Cox ES Blackbird SJ Heyes TJ Pakeman RJ Le Duc MG 《Journal of environmental management》2007,85(4):1034-1047
Conservation management in Europe is often geared towards restoring semi-natural ecosystems, where the objective is to reverse succession and re-establish early-successional communities, to comply with national and international conservation targets. At the same time, it is increasingly recognised that ecosystems provide services that contribute to other, possibly conflicting policy requirements. Few attempts have been made to define these conflicts. Here, we assess some potential conflicts using a Calluna vulgaris-dominated moorland invaded by bracken (Pteridium aquilinum) as a model system, where the current policy is to reverse this process and restore moorland. We examined impacts of bracken control treatments on services (stocks and losses of C and mineral nutrients), litter turnover and biodiversity within a designed experiment over 7 years. Bracken litter was >2000 g m(-2) in untreated plots, and treatments reduced this quantity, and its element content, to varying degrees. Cutting twice per year was the most successful treatment in reducing bracken litter and its element content, increasing litter turnover, and increasing both mass and diversity of non-bracken vegetation. Diversity was greatest where bracken litter had been reduced, but species composition was also influenced by light sheep grazing. There was a significant loss of some chemical elements from bracken that could not be accounted for in other pools, and hence potentially lost from the system. In absolute terms large amounts of C and N were lost, but when expressed as a percentage of the total amount in the system, Mg was potentially more important with losses of almost a third of the Mg in the surface soil-vegetation system. There is, therefore, a potential dilemma between controlling a mid-successional invasive species for conservation policy objectives, especially when that species has evolved to sequester nutrients, and the negative effect of increasing environmental costs in terms of carbon accounting required, the potential input of nutrients to aquatic systems, and long-term nutrient loss. There is, therefore, a need to balance conservation goals against potential damage to biogeochemical structure and function. 相似文献
992.
The US EPA's current regulatory approach for combustion and incineration sources considers the use of real-time continuous emission monitors (CEMs) for particulate, metals, and organic compounds to monitor source emissions. Currently, the CEM technologies to support this approach have not been thoroughly developed and/or demonstrated. The EPA's Air Pollution Prevention and Control Division has developed a near-real-time volatile organic compound (VOC) CEM, using an on-line gas chromatograph (OLGC), capable of measuring over 20 VOCs at concentrations typically present in well-operated combustion systems. The OLGC system consists of a sample delivery system, a sample concentrator, and a GC equipped with both flame ionization and electron capture detectors. Application of the OLGC system was initially demonstrated through participation in the 1995 US EPA/DOE CEM demonstration program. Additional work has improved system performance, including increased automation and improved calibration technique. During pilot-scale incineration testing, measurement performance was examined in detail through comparisons to various CEM performance criteria. Specifically, calibration error, calibration drift error, and system bias were examined as a function of full scale (absolute error) and gas concentration (relative error). Although OLGC measurement performance was not able to meet standard EPA CEM measurement performance criteria, measurement performance was encouraging. The system demonstrated the ability to perform hourly trace level VOC measurements (0–100 ppbv) for as many as 23 different VOCs with boiling points ranging from −23.7 to 180.5 °C at a known level of measurement performance. This system is a suitable alternative to VOC reference method measurements which may be performed only intermittently. 相似文献
993.
Bryan P. Wallace Jeffrey A. Seminoff Susan S. Kilham James R. Spotila Peter H. Dutton 《Marine Biology》2006,149(4):953-960
Oceanographic sampling is often limited to local and temporally concise assessments of complex, transient, and widespread phenomena. However, long-lived, migratory pelagic vertebrates such as leatherback turtles (Dermochelys coriacea, Vandelli 1761) can provide important integrated information about broad-scale oceanographic processes. Therefore, the present study analyzed stable carbon and nitrogen isotope ratios (δ13C and δ15N) of egg yolk and red blood cells from nesting leatherback populations from Costa Rica in the eastern Pacific in 2003–2004 and 2004–2005 and from St. Croix in the North Atlantic in 2004 and 2005 to establish differences between nutrient sourcing and its influence on higher trophic level consumers in both ocean basins. Whereas δ13C signatures were similar between Costa Rica (−19.1±0.7‰) and St. Croix (−19.4±1.0‰) leatherbacks, reflecting the pelagic foraging strategy of the species, Costa Rica leatherback δ15N signatures (15.4±1.8‰) were significantly enriched relative to St. Croix leatherback δ15N signatures (9.8±1.5‰). This δ15N difference likely reflects inter-basin differences in nitrogen cycling regimes and their influence on primary productivity being transferred through several trophic levels. Thus, high-order marine consumer movements, habitat preferences, and stable isotope signatures can be combined with ocean sampling to elucidate interactions between oceanographic processes and marine megafauna.Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
994.
995.
浅析环境权的法理基础 总被引:3,自引:0,他引:3
胡通碧 《中国人口.资源与环境》2002,12(4):32-34
环境权正在从应有权利走向实在权利,本文分析了环境权的法理基础存在的原因,指出环境权法理基础就是生存、自由、平等、可持续发展、共存。 相似文献
996.
Maya G. Hutchins Jeffrey D. Colby Gregg Marland Eric Marland 《Mitigation and Adaptation Strategies for Global Change》2017,22(6):947-972
The quantification of fossil-fuel-related emissions of carbon dioxide to the atmosphere is necessary in order to accurately represent carbon cycle fluxes and to understand and project the details of the global carbon cycle. In addition, the monitoring, reporting, and verification (MRV) of carbon dioxide emissions is necessary for the success of international agreements to reduce emissions. However, existing fossil-fuel carbon dioxide (FFCO2) emissions inventories vary in terms of the data and methods used to estimate and distribute FFCO2. This paper compares how the approaches used to create spatially explicit FFCO2 emissions inventories affect the spatial distribution of emissions estimates and the magnitude of emissions estimates in specific locales. Five spatially explicit FFCO2 emission inventories were compared: Carbon Dioxide Information and Analysis Center (CDIAC), Emission Database for Global Atmospheric Research (EDGAR), Fossil Fuel Data Assimilation System (FFDAS), Open-source Data Inventory for Anthropogenic CO2 (ODIAC), and Vulcan. The effects of using specific data and approaches in the creation of spatially explicit FFCO2 emissions inventories, and the effect of resolution on data representation are analyzed using graphical, numerical, and cartographic approaches. We examined the effect of using top-down versus bottom-up approaches, nightlights versus population proxies, and the inclusion of large point sources. The results indicate that the approach used to distribute emissions in space creates distinct patterns in the distribution of emissions estimates and hence in the estimates of emissions in specific locations. The different datasets serve different purposes but collectively show the key role of large point sources and urban centers and the strong relationship between scale and uncertainty. 相似文献
997.
以某高海拔地区污水处理厂的二级生化处理水为研究对象,通过对人工湿地进出水中COD、NH+4-N、TP浓度的变化,研究了水力负荷、气水比两个参数对人工湿地净水效果的影响。结果表明:人工湿地去除生活污水中COD、NH4+-N、TP的最佳水力负荷为0.33 m3/(m2·d)、气水比为3:1,在此最佳试验条件下,COD、NH4+-N、TP的去除率分别可达84%、69%、68%,出水水质满足《地表水环境质量标准》Ⅲ类水质标准。 相似文献
998.
气候变化问题日益凸显。应对和适应气候变化刻不容缓。然而,短期内无法有效减缓气候变化产生的不利影响。因此,有必要针对不同领域制定相应的适应措施来提高人们对气候变化的适应能力。北京作为人口众多的大城市及我国的缺水城市之一,气候变化无疑将加剧水资源的供需矛盾。本文针对北京市水资源现状及气候变化对北京市水资源领域已经形成的影响,从自然、工程、政策制度三个角度探讨了北京市水资源领域适应气候变化可采取的对策及保障措施。 相似文献
999.
宁南山区林地土壤原位矿化过程中碳氮转化耦合特征 总被引:3,自引:1,他引:2
为了解宁南山区典型植被恢复模式之一——人工林地土壤碳氮转化的特征以及二者的关系,运用PVC顶盖埋管法进行1 a的原位矿化培养实验,每隔2个月采样,研究柠条、山桃、山杏林地中土壤有机碳、可溶性有机碳和微生物量碳与土壤有机氮、无机氮以及净氨化速率、净硝化速率、净矿化速率和微生物固定速率在一年中的变化特征以及碳氮耦合关系.结果表明在原位培养过程中,61~120 d碳氮的变化最明显,主要受到土壤水分的影响;土壤有机碳和全氮极显著正相关,土壤微生物量碳氮、可溶性有机碳氮显著正相关;土壤有机碳转化速率显著影响净氨化速率、净硝化速率和MBN转化速率,且符合一元线性回归方程;柠条地培养一年后土壤微生物商(MBC/SOC)、MBN/SON显著升高,而且净硝化速率、净矿化速率显著大于山桃和山杏. 相似文献
1000.
Ali Aydin Jennifer L. Cannon Tong Zhao Michael P. Doyle 《Food and environmental virology》2013,5(4):215-219
Influenza A virus poses a major public health concern and is associated with annual epidemics and occasional pandemics. Influenza A H3N2 viruses, which are an important cause of human influenza, can infect birds and mammals. Contaminated undercooked poultry products including eggs with avian influenza virus constitute a possible risk of transmission to humans. In this study, a novel levulinic acid plus sodium dodecyl sulfate (SDS) sanitizer was evaluated for eggshell decontamination. Influenza A H3N2 virus-inoculated chicken eggshells were treated with a 5 % levulinic acid plus 2 % SDS, 2 % levulinic acid plus 1 % SDS, and 0.5 % levulinic acid plus 0.5 % SDS liquid solution for 1 min. Log reductions of viable viruses were observed by plaque assay. The 5 % levulinic acid plus 2 % SDS sanitizer provided the greatest level of influenza A H3N2 virus inactivation (2.23 log PFU), and differences in virus inactivation were observed for the various levulinic acid plus SDS concentrations tested (P ≤ 0.05). To the best of our knowledge, this is the first study demonstrating influenza A H3N2 virus inactivation on eggshells using a novel levulinic acid plus SDS sanitizer. The sanitizer may be useful for reducing egg contamination and preventing the spread of avian influenza virus to humans. 相似文献