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131.
The specific methods used for recovery of the aquatic ecological system in the shallow lake are proposed. This research has been done from three aspects:1) the design of the species used for the ecological recovery; 2) the design of optimization and allocation of the aquatic communities; and 3) the design of regional arrangement of the aquatic communities. On the basis of research, the pioneer plant and the species used to establish the communities are proposed. The aquatic plant allocation focuses on the emergent aquatic plant and submergent aquatic plant. Meanwhile, the regional arrangement has been done in the aquatic plant recovery area in the Caohai Lake and the east west bank of the outer lake. 相似文献
132.
地质岩心钻探中,岩心采取率一直是地质找矿、地学科研工作者重点关注的对象,也是岩心钻探重要的考核指标。传统的钻探取心方法在松散、软弱、含盐地层,特别是含易溶盐地层的取心质量不佳;绳索取心钻探在完整地层取心效果较为理想,同时可大大提高劳动生产率、降低劳动强度,而对于松散、软弱地层,其取心难度比起传统钻探有时更为复杂。通过柴达木盆地达布逊干盐湖科学钻探工程,对钻遇的地表层、松散地层如何采取技术方法提高岩心采取率进行了探索和研究。实践证明,通过改善冲洗液性能、改进取心卡簧特性及钻头出水方式3个方面技术措施,可大大提高绳索取心钻进在松散、软弱、弱固结、含盐地层的岩心采取率,由改进前的平均30%提高为平均96%。 相似文献
133.
Here we report on the different sampling strategies for almost seven years of sampling rocks/sediments for the determination of As within the Intermediate Aquifer System (IAS) and upper Floridan Aquifer System (FAS), a very large and productive limestone aquifer spanning from Georgia into Florida. In the FAS, As contamination has become a recurring problem during aquifer storage and recovery (ASR), particularly in central and south Florida.To investigate these phenomena, samples from solid drill cores and rock cuttings were collected from the Hawthorn Group, Suwannee Limestone, Ocala Limestone and Avon Park Formation. Samples were taken along drill cores and rock cuttings (referred to as ‘interval’ samples) or from particular drill core sections and rock cuttings (referred to as ‘targeted’ samples) likely to contain elevated concentrations of As as indicated by the presence of pyrite, hydrous ferric oxide, organic matter, clay minerals, fracture surfaces, and high permeable (moldic) zones.Arsenic was present in all of the stratigraphic units at low concentrations, close to the global average for As in limestone of 2.6 mg/kg. The highest As concentration was 69 mg/kg. In all units, however, the average bulk As concentration in the targeted samples was substantially higher than that in the interval samples. Based on direct spot measurements by electron microprobe and indirect calculations, pyrite was identified as the main source of As in the FAS. Concentrations in pyrite ranged from less than 100 mg/kg to more than 11,000 mg/kg. Because pyrite is heterogeneously distributed, both vertically and horizontally in the sampled stratigraphic units, the same was observed for the distribution of As. However, As concentrations generally decreased with depth, i.e., highest As values in the Hawthorn Group and lowest As values in the Ocala Limestone and Avon Park Formation. Compared to pyrite, other trace minerals contained much less As.The average As concentrations of the two types of sample media (solid cores and rock cuttings) were quite similar. These results indicate that if simply the average bulk rock As concentration of a geologic unit is the desired outcome of an investigation, either interval or targeted sampling of rock cuttings, seems to be sufficient. This is particularly important when time and money are a factor. This approach could work equally well for any other trace element. Structural sedimentary information, such as fractures, etc., is likely lost, however, when sampling rock cuttings. Thus, if this information is required, solid core samples need to be collected by hollow core diamond drilling. 相似文献
134.
塔里木河流域适应气候变化和人类活动的应对措施 总被引:2,自引:1,他引:2
自2001年开始实施塔里木河流域近期综合治理工程,提出了以强化流域水资源统一管理和调度为核心,以源流区节水改造和干流河道治理为重点进行综合治理,积极稳妥地进行经济结构调整,实施退耕封育保护,有效保护好现有天然林草植被.通过向塔里木河下游生态输水,干涸近30a的台特玛湖于2001年11月16日开始有水,使塔里木河下游绿色走廊得到初步复苏等,流域生态环境得到极大的恢复.然而,自2007年以来,塔里木河向下游输水已大为减少,仅能输水到中游,特别是2009年水文干旱,塔里木河干流断流达1 100km多,使下游绿色走廊再度陷入生态危机.为此,需要重新审视塔里木河流域的综合治理,从加强源流治理开始,来巩固干流治理成果.认真总结10a来治理经验与教训,针对人类活动和气候变化对源流与干流造成的影响程度,积极采取应对措施. 相似文献
135.
Due to energy shortage and increasing environmental awareness, resources in shallow underground space have been rapidly exploited and utilized. So that studying variation characteristics of geothermal response in gneiss is necessary for effective and rational use of underground heat. Based on field test of thermal response in gneiss under hydrogeological survey project carried out in shallow geothermal energy development zone in Liaoning Province, this thesis analyzes mathematical statistics of geothermal response characteristics in main gneiss of Laoning Province. The initial formation temperature ranges from 10.80℃ to 15.80℃ according to field test. The statistical results show that in the condition of natural water content, the average thermal conductivity of Quaternary loose rocks comes as clay silty silty fine sand medium sand coarse sand gravelly sand. This order is consistent with thermal conductivity characteristics of gneiss obtained in the laboratory. Formation temperature recovery in different strata follows as granite medium sand clay. This order is opposite to the absolute value of temperature recovery curve slope of corresponding lithology, which shows that the stratum with higher temperature recovery rate has lower temperature recovery curve slope. 相似文献
136.
Bacterial interaction with oil and sea water, in a porous medium, was studied using a transparent micro model mounted on
a cybernetic-controlled positioning board of an inverted microscope. This was interfaced with computer-operated image analysis
and surveillance equipment. Consecutive flooding of the model allowed oil to become trapped by capillary forces. Hydrocarbonoclastic
bacteria were inoculated. The interaction of biofilm and oil was monitored during a period of 25 days, while mineral salts
were supplied intermittently. A unique feature of biofilm behaviour was discovered. The phenomenon is discussed, and calculations
are presented. A possible explanation of the phenomenon appears to be local reductions of the surface tension. The phenomenon
helps explain why bacteria are able to mobilise oil trapped by capillary forces without reducing the interfacial tension to
a level that leads to an increase in the capillary number sufficient to explain incremental oil recovery. The experimental
design is believed to be suitable for studying biofilm behaviour on the pore level.
Received: 26 January 1998 · Accepted: 9 July 1998 相似文献
137.
138.
Biodiversity is a critical component of the natural environment and the protection of it often meant the displacement of local communities in developing countries. The Richtersveld National Park (South Africa) is unusual in that it forms part of the Richtersveld communal rangeland and is currently managed for goat and sheep farming as well as biodiversity conservation under a contractual agreement. These two objectives are not regarded as mutually compatible and have created tension between conservation management officials and pastoralists. We set out to examine the consequences of reducing herd size in a communal livestock production system in support of biodiversity conservation in a protected area. Kidding, animal offtake (sales and slaughter), mortality and herd persistence showed no clear incentives for an individual pastoralist to reduce herd size. Reducing herd size is not considered a recommended intervention for the conservation of biodiversity or livelihood improvement of pastoralists in the park. The future of the natural resources of the national park is dependent on a delicate balance between the needs of the pastoralists and the conservation of those very same resources that the pastoralists use. 相似文献
139.
Rikke Bruhn Jenő Nagy Morten Smelror Henning Dypvik Sylfest Glimsdal Richard Pegrum Carlo Cavalli 《Basin Research》2023,35(2):620-641
The Mjølnir impact crater in the Norwegian Barents Sea features among the 20 largest impact craters listed in the Earth Impact Database. The impact is dated to 142 ± 2.6 Ma, corresponding closely to the Jurassic/Cretaceous boundary in the Boreal stratigraphy. Multidisciplinary studies carried out over the last three decades have suggested that the up to 40 km wide crater was created by a 1–3 km diameter impactor colliding with a shallow epicontinental sea, causing regional havoc and a regional ecological crisis that followed in its wake. Only minor evidence for the consequences of the impact for the surrounding depositional basins has been documented so far. This study describes a large submarine slump penetrated by hydrocarbon exploration well 7121/9-1, located in the southern Hammerfest Basin and approximately 350 km away from the impact site. The slump is dated by a black shale drape, which contains characteristic impact-related biotic assemblages and potential ejecta material. This precise dating enables us to associate the slump with large-scale fault movements and footwall collapse along the basin-bounding Troms-Finnmark Fault Complex, which we conclude were caused by shock waves from the Mjølnir impact and the passage of associated tsunami trains. The draping black shale is interpreted to represent significant reworking of material from the contemporary seabed by tsunamis and currents set up by the impact. 相似文献
140.
The fate of waste in Hawaii: Technology assessment and solid waste planning in Hawaii, 1968–78 下载免费PDF全文
Jordan P. Howell 《Singapore journal of tropical geography》2015,36(1):67-82
In this article I consider the initial period of solid waste management planning in the US state of Hawaii. The State encountered a number of economic and ecological controversies during its solid waste management planning, a process that was prompted by the US Environmental Protection Agency. Some issues, like project financing, were common across the US, while others, such as the potential of waste materials to reduce reliance on imported food and materials, were more unique to Hawaii. The controversies from this initial planning period were never quite fully resolved; as they lingered, they were interpreted differently across the Islands. Based on a close reading of government, advocacy group, waste industry and news media documents, I examine the controversies over solid waste management of the time and consider how the ‘dual nature’ of waste in Hawaii—simultaneously an ecological threat and (potential) economic input—shaped the adoption of solid waste management systems there. This article adds to an expanding literature examining infrastructure in environmental and technology histories. 相似文献