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141.
阳宗海表层沉积物中的重金属生态风险评估 总被引:1,自引:0,他引:1
对从阳宗海湖底表层采集的25组沉积物样品中的10种重金属质量比进行分析,结果表明,Ti、Mn、Zn、V、Cr、Cu、Ni、Co、Pb和As的质量比平均值均超过了当地土壤背景值。而重金属系统聚类分析表明,Zn、Cr、Pb、As高度相关,其污染主要由于人类活动造成;Ti、Mn、V、Cu、Ni、Co的分布特征相似,其污染原因以岩石风化等自然因素为主。单因子富集系数评价表明,阳宗海10种重金属均达到了中度富集程度,其中As、Cu、Cr富集程度较为突出。用Hakanson潜在生态风险指数法评价阳宗海表层沉积物中重金属的生态风险,结果表明,阳宗海表层沉积物中重金属的生态风险总体属轻微程度,阳宗海南岸局部区域达到中等生态风险程度。几种重金属对阳宗海生态风险的贡献由大到小依次为As、Cu、Co、Ni、Pb、Cr、V、Zn、Mn、Ti,其中,As是阳宗海最突出的生态风险因子。 相似文献
142.
洞庭湖区供水安全问题 总被引:1,自引:0,他引:1
随着气候变化和人类水土资源开发活动影响的深入,洞庭湖区面临着严重的供水安全问题。现结合供水安全的含义,从水量、水质变化以及供水设施等方面,分析洞庭湖区水量的变化以及水质状况演变趋势,并从科学调水用水、水源保护、法规制度的制定等3方面提出了相应的对策与措施,为科学的解决本地区的供水安全问题提供依据,以期能够引起人们对洞庭湖区供水安全方面问题的重视。 相似文献
143.
泸沽湖的区位特征,一方面使其面临着激烈的空间近邻竞争;另一方面也带来集聚效应.成功的旅游产品的规划设计,不仅会给泸沽湖景区带来良好的效益,也必然会拉动丽江市战略性支柱产业——旅游业的发展.下阶段泸沽湖旅游产品总的开发方向为:刻画主题,树立品牌,提升形象,并通过基础产品、特色产品、提升产品三个层次,将泸沽湖打造成以高原湖泊和摩梭女性文化为核心的旅游产品. 相似文献
144.
修公路是致富之道,也是破坏区域生态平衡的元凶。合肥市修建巢湖环湖观光大道,在可能促进经济增长效应的同时,必将给巢湖套上一把"枷锁",阻碍湖与岸的生物能量交流,破坏水文体系,减少湿地面积,加重水体污染,阻断动物的食物链,严重损害包括合肥在内的巢湖区域生态平衡。巢湖环湖观光大道通,鱼死水臭,天上少飞鸟,陆岸无走兽的局面,决不是危言耸听。本文分析了巢湖环湖大道对巢湖的危害,并在借鉴国内外学者研究成果的基础上,就保护巢湖提出对策建议。 相似文献
146.
沉积物中部分固定的磷可通过分解或溶解作用而释放磷酸盐到沉积物间隙水中;再生的磷可能释放到上覆水体中,或在沉积物中作为一种自生相而再沉淀,或被沉积物的其它组分所吸附。本文描述了磷在沉积物-水界面的迁移过程,并对影响磷循环的因子及其磷自沉积物释放的机制作一简要概述。 相似文献
147.
Julia Peck 《History of Photography》2013,37(3):214-233
This paper re-investigates notions of performed Aboriginality in relation to photographs made at Lake Tyers Mission Station, Victoria, Australia, and argues that Nicholas Caire's photographs reveal complex Aboriginal subjectivities. The photographs, made originally in 1886 and distributed to tourists, were later reproduced and circulated in book format in 1897. The first presentation of the photographs, whilst focusing on historical Aboriginality, contains traces of cross-cultural hybridity. However, the later presentation of the work reinforces historical and traditional material culture over cross-cultural dialogue. This paper argues that the desire to find historical notions of Aboriginality on mission stations in Victoria was not just due to the establishment of hierarchical racial theories in the latter part of the nineteenth century (generating the idea that Aborigines could not change and adapt to notions of ‘civilisation’) and doubts about the success of mission stations, but also because there was an interest in Aborigines who had experienced little assimilation from more remote parts of the continent of Australia. This curiosity in pre-contact Aboriginality fuelled tourism in Victoria to accessible mission stations such as Lake Tyers. 相似文献
148.
Douglas Bessette Michelle Rutty Grant Gunn Volodymyr Tarabara Robert Richardson 《Journal of Great Lakes research》2021,47(1):226-235
Using the psychometric paradigm of risk in conjunction with surveys of the Michigan public (n = 638) and a regional planning organization (n = 65), we examine the perceived risk and concerns associated with underwater oil pipelines, the Enbridge Line 5 pipeline in particular, and oil spills under ice. The fate of Line 5 is heavily debated in Michigan, specifically the portion that traverses the Straits of Mackinac, which can be ice-covered for months. Scant literature examines how individuals perceive the risk associated with Line 5, its alternatives, or potential spills in open water or under ice. Here we identify considerable concern regarding both the pipeline and the potential for spills under ice on behalf of the public, and increased concern about spills under ice on behalf of the planning organization. Organization members' concerns are significantly predicted by beliefs about the difficulty in remediating spills, however not by beliefs about spills' likelihood, difficulty in detection, noticeability, or consequences. Our results identify the need to better examine and communicate the risks associated with underwater pipelines and spills, both in open water and under ice, as well as options for remediating oil captured under ice. Furthermore, we recommend the adoption of decision-making and risk governance processes that explicitly expand analysis of the social, economic and environmental tradeoffs of underwater pipelines such as Line 5. 相似文献
149.
《Journal of Great Lakes research》2021,47(5):1386-1399
Fishes typically occupy a species-specific temperature range, with their occupied depth being related to the lake’s temperature profile. When a fish’s preferred temperature range coincides with the thermocline, the location of their preferred thermal habitat is influenced by the rise and fall of internal waves, leading to possible changes in fish depth. These internal waves are common in large, stratified lakes, yet we do not know how they affect the spatial distribution and behavior of freshwater fishes. We conducted nighttime hydroacoustic surveys in a large, deep embayment of a large thermally stratified lake to observe whether pelagic fish respond to vertical oscillations of the thermocline caused by internal waves. The coldwater pelagic fish in our study (primarily cisco, Coregonus artedi) typically occupied a narrow vertical band approximately 5–8 m thick and temperatures between 10.8 ± 0.8–13.6 ± 1.6 °C (fishes sized 106–500 mm), just below the thermocline (centered around 15–17 °C). Importantly, the upper bound of fish depth varied in response to vertical thermocline movements associated with internal waves, suggesting fish respond to changes in their physical environment on timescales commensurate with basin-scale internal wave periods (hours to days), to remain within their preferred thermal habitat. Dissolved-oxygen levels were typically above avoidance thresholds of these fish, thus not likely exerting a strong influence on fish location. Our findings emphasize the need to account for internal waves when designing hydroacoustic and netting surveys, as thermocline movements can influence where fish are located. 相似文献
150.
《Soils and Foundations》2019,59(2):351-366
The system of the partial compensation of masses in the lacustrine zone of the Mexico Basin has been conceptualized, developed, used and improved over the past five decades as a foundation alternative for different types of roadways. This kind of foundation has been used in highways and runways built on lacustrine soils to reduce the settlement that can affect the service and operation conditions of those structures. In the construction of the new Mexico City International Airport in the Texcoco Lake area, various alternatives for runway foundations were evaluated through different test sections that were constructed to identify which of them would yield an adequate transfer of stress and prevent excessive total and differential deformations of the soil deposits. In this work, the behavior of the test section of the system of the partial compensation of masses, built in the Texcoco Lake area, is studied. An exploration campaign was performed; it consisted of different field and laboratory tests to determine the stratigraphic profile and the index and mechanical properties of the soil strata. Numerical models were applied using the finite element software PLAXIS 2D to analyze the behavior of the test section and to determine the maintenance frequency required to preserve the functionality of future runways. To validate the capability of the numerical models to properly simulate the stress-strain behavior of the test section, a comparative analysis was performed between the data obtained from the instrumentation installed on the test section and the results obtained from the finite element software. Once the numerical models were calibrated, the medium- and long-term behaviors of the test section were predicted, and the evolution over time of its surface geometry and transverse slopes were obtained. 相似文献