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81.
There has been global interest in the exploitation of rich hydrocarbon resources in the Arctic for decades. However, recent low oil prices, a low carbon economy climate agenda, and technical challenges of Arctic oil extraction have curbed interest in these Arctic resources. Despite a recent reluctance to explore and develop an offshore Arctic drilling industry, a resurgence in oil and gas prices could spark renewed interests that could pose unacceptable risks of pollution from oil spills. These risks are further compounded by complex governance and sovereignty issues between circumpolar nations. This paper (i) compares cycles of Arctic hydrocarbon exploration and exploitation activity with global energy prices; (ii) outlines current pollution abatement techniques under pan-Arctic national regulations to identify potential gaps; (iii) describes current international frameworks for Arctic governance to highlight how problems could arise if offshore oil drilling returns to the Arctic and associated spills migrate to international waters; and (iv) provides policy recommendations to aid both national and international policy-makers regarding pollution abatement methods for future Arctic drilling.  相似文献   
82.
文章在辨析和定义海洋生态系统概念的基础上,分析辽宁海洋生态系统的恶化态势,主要体现在过度捕捞导致的海洋生物资源衰退,陆源污染、养殖污染和油类污染导致的海洋水体环境污染以及填海造地和海岸侵蚀等导致的海岸生态系统弱化。进而,从公地悲剧理论、环境库兹涅茨理论、外部性理论和产权理论4个维度做出具体的经济学阐释,阐明海洋生态系统恶化态势与经济开发行为之间的关系。  相似文献   
83.
相比陆上油气开发工程和其他海洋工程而言,海洋油气开发工程有其自身的特点,海洋油气开发工程环境影响评价应关注的内容与其他工程有所不同。文章通过分析海洋油气开发工程的特点以及对环境影响的特点,提出海洋油气开发工程环境影响评价要点,即包括施工期悬浮泥沙及钻井液钻屑排放对海洋生态环境的影响、运营期含油生产水排放对海洋生态环境的影响、工程建设对海洋环境敏感目标的影响、溢油事故环境风险分析、污染防治及生态保护措施,并针对目前海洋油气开发工程环境影响评价存在的问题提出改进建议。  相似文献   
84.
Based on rock and fossil data from the Upper Cretaceous of the El Hassana Dome (Abu Roash, Egypt), factors controlling facies architecture and the nature of biotopes are highlighted. The succession formed on a non-rimmed shelf, the architecture of which varied from an inner to an outer shelf setting upsection. Macrobenthic biotopes are reconstructed and their palaeoecological significance assessed using a novel ternary plot. Based on diversity and community structure (770 specimens assigned to 28 bivalve and gastropod taxa), four paucispecific associations are identified. These are: 1. the ‘Cucullaea’ Assemblage, a low-energy, soft-substrate, oligotrophic outer shelf environment with reduced terrigenous input dominated by infaunal bivalves and hexactinellid sponges; 2. the ‘Plicatula’ Assemblage, a low-energy, restricted inner shelf lagoonal setting with soupy substrates and dysoxia below the sediment-water interface dominated by plicatulid and ostreid bivalves, 3. the ‘Durania’ Assemblage, a high-energy, high-temperature, shoal environment dominated by elevator rudists with minor numbers of echinoids, corals and bryozoans, which together form several biostromes. and 4. The ‘Trochactaeon’ Assemblage, which share the same characteristics of the ‘Durania’ Assemblage. The paucispecific nature of these biotopes is indicative of different stress factors. Consequently, the predominant taxa exhibit different degrees of adaptive strategies. In addition to global sea level, local tectonics have significantly affected facies distribution and biotope structure. The shallower facies during the early Turonian and the dysoxia spanning the Coniacian–Santonian were linked to synsedimentary tectonics, which formed many barriers and led to circulation restrictions.  相似文献   
85.
针对特殊环境胁迫下河流健康评价的不足,本文依据生态中心与人类中心相结合、整体论、运动论等哲学观点,建立4级模式、参数权重法、百分制计算的评价体系。第2级评价参数为流域环境胁迫程度、河流状况、防治环境胁迫潜力三部分。以海水入侵影响的黄海岸沿海诸河为例,评价结果为72分,准确反映了该河流的健康状况、危害程度和防治潜力,同时高权重参数为保护河流提供决策依据。  相似文献   
86.
本文通过对呼伦贝尔湿地保护存在的主要问题的论述,列举了呼伦贝尔市湿地保护存在的主要问题,提出了保护呼伦贝尔湿地的相应对策。  相似文献   
87.
This paper presents the first attempt to use environmental magnetism to quantify sediment provenance on a managed realignment (MR) site. MR is one technique for creating/restoring intertidal habitats and improving the standard of coastal flood protection. Monitoring of MR sites is essential for determining how successful they are at achieving these aims, and normally includes measurement of sedimentation rates through the use of accretion plates and sediment erosion tables (SETs). One limitation of this technique is that the provenance of sediment accreting on realigned surfaces cannot readily be quantified. Our results demonstrate that magnetics-based fingerprinting can successfully apportion sediment source contributions to created/restored coastal saltmarshes with an efficiency similar to that of existing un-mixing models applied to other habitats (82.87%). Analysis of mineral magnetic properties (χFD, IRMsoft and SIRM) demonstrated that the majority of sediment accreting on the Freiston Shore MR Site (Lincolnshire, UK) is derived from established saltmarshes seaward of the breached embankment. This indicates that the MR site may be growing at the expense of neighbouring saltmarshes—thereby undermining the habitat-creation objectives used to justify MR. It is recommended that future MR monitoring programmes consider the provenance of post-breach deposits to help identify any adverse impacts that wetland creation/restoration may have on existing habitats. Further testing of environmental magnetism in coastal saltmarshes and MR sites is necessary to validate wider use of the technique.  相似文献   
88.
Mineral magnetic signatures in a long core from Lake Qarun, Middle Egypt   总被引:1,自引:0,他引:1  
The analysis and interpretation of changes in mineral magnetic signatures from a long (ca. 8.2 m) sedimentary sequence recovered from Lake Qarun, Middle Egypt in 2003 spanning a timescale of approximately the last 2,000 years is reported. A suite of mass specific susceptibility and magnetic remanence measurements were made at irregular intervals downcore on 39 samples. These samples were selected on the basis of trends and abrupt changes in whole-core magnetic susceptibility measured using a Bartington® MS2E sensor and were analysed for low and high temperature loss on ignition and their particle size distribution. Trends in all mineral magnetic concentration parameters are remarkably similar and were initially used to divide the core into three magnetically distinct zones. The upper and lower sections of the core (0–119 cm and 445–822 cm depth) are characterised by low values for all magnetic concentration parameters. Between 153 and 380 cm depth, concentration parameters are considerably higher, although somewhat variable. The S ratio and percentage loss of remanence after 24 h (IRMloss) follow a different trend and are inversely related to each other. A low S ratio (<0.7) is associated with a loss of remanence of >4%. On the basis of these parameters, the core can be divided into four zones, and differences in magnetic mineralogy between these four zones were confirmed by measurement of IRM acquisition curves. The major difference between concentration parameters and ratios or percentage loss of IRM lies in the identification of an additional zone below 619 cm depth where the S ratio is high and IRMloss is low. There is little evidence to suggest that the magnetic signatures are controlled by particle size or by trends in organic matter and/or carbonate content. The signatures appear to be predominantly detrital and show little evidence of post-depositional alteration through dissolution or authigenic addition of bacterial magnetite or greigite. Analysis of Saharan dust deposition rates in Northern Egypt suggests that atmospheric fallout is likely to make only a very minor contribution (<1%) to sedimentation rates in Lake Qarun. The downcore trends therefore appear to reflect major changes in fluvial sediment sources over the ca. 2,000 year time period spanned by this ~8 m core. Preliminary mineral magnetic characterisations of potential local sources suggest that these cannot account for the range of signatures recorded in the Qarun sediments and it is hypothesised that these sediments are derived from Nile river floods.  相似文献   
89.
A field survey of zooplankton communities was carried out in 32 recently established tropical semi-arid reservoirs in the highlands of Northern Ethiopia with the aim to identify to what extent environmental factors determine species composition of the cladoceran community in such isolated and young reservoirs. To address seasonal variation, the survey was carried out both at the beginning and the end of the dry season. A total of 15 species of cladocerans were identified. Daphnia was the most abundant cladoceran genus, and was present in all reservoirs. Using presence-absence data, no association between cladoceran community composition and geographic distance was found. RDA results indicate that the set of environmental variables that explained cladoceran community composition differed among seasons. Depth, altitude and fish biomass showed a significant association with cladoceran community composition during the wet season, whereas variation in cladoceran community structure was associated with phytoplankton biomass in the dry season. The relative abundance of Daphnia was much higher in the pelagic than in the littoral zone of our study systems. Two key groups of pelagic filter-feeding cladocerans, Diaphanosoma and Daphnia, showed a clear pattern, in which one or the other tended to strongly dominate the community. In addition, we observed a negative association between dominance of Daphnia in the zooplankton community and dominance of cyanobacteria in the phytoplankton community.  相似文献   
90.
环境规制对无锡市区污染密集型制造业区位选择的影响   总被引:1,自引:0,他引:1  
高爽  魏也华  陈雯 《湖泊科学》2012,24(6):883-890
随着生态环境的恶化,发达地区制造业区位选择表现出强烈的环境容量制约性和政府规制主导性.本文在对1998-2008年无锡市区污染密集型制造业格局演变分析的基础上,构筑了引入环境规制影响因子的企业区位演变理论分析框架,并运用GIS空间自回归模型,对以上理论框架进行验证.结果表明,1998-2003年影响企业区位选择的主要要素为交通可达性、土地价格、开发区规划等,而环境规制相关要素对其影响不显著;而2003-2008年,表征环境规制影响强度的水质目标、清水通道等因子对制造业区位选择的影响显著,这表明环境规制开始成为影响污染密集型制造业区位的重要因子.本研究对于正确制定城市产业结构调整政策和合理引导经济环境协调发展具有重要的理论借鉴意义.  相似文献   
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