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611.
Inês Martins Richard P. CossonVirginie Riou Pierre-Marie SarradinJozée Sarrazin Ricardo S. SantosAna Colaço 《Deep Sea Research Part I: Oceanographic Research Papers》2011,58(3):306-315
The turbulent mixing of hydrothermal hot fluid with cold seawater creates large chemical gradients at a small spatial scale that may induce variable physiological and biochemical adaptations within the vent fauna. The adaptation to such a variable environment by the vent mussel Bathymodiolus azoricus relies on a dual symbiosis hosted in the gills, and digestion of particulate organic matter. The surrounding environment not only provides the necessary energy sources and suspended organic particles for the vent mussel nutrition, but also potentially toxic compounds such as metals. Our main goal was to see if there is a relation between metal accumulation in mussel organs and the chemical characteristics of their close environment. Mussels were collected at six locations in a cold part of the Eiffel Tower fluid-seawater mixing zone, characterized by distinct chemical compositions. Metals (Cd, Cu, Fe and Zn) and metallothioneins were quantified in the gills and digestive gland. The physiological condition of the sampled mussels was also evaluated using tissues and gill indices. Our study indicates that the accumulation of metals in B. azoricus is related to their spatial distribution and linked to fine scale environmental conditions that influence the physiological status of the organism. 相似文献
612.
613.
Environmental and land defenders play a crucial role in attempts to slow down environmental change and address power inequalities in land-use and resource development. Yet, they frequently face repression, including defamation, criminalization, and assassination. Recent policy and media coverage initiatives have provided much needed attention to the protection and support of defenders, but there has so far been little systematic analysis of patterns and determinants of repression at multiple scales. Here, we use databases providing the best available worldwide record of cases of socio-environmental conflicts and killings of defenders to identify patterns of repression and potential determinants of killings. Globally, about a third of socio-environmental conflicts involve mass mobilization, arrests and direct forms of violence. These ‘high intensity’ conflicts are more frequent in Asia and Latin America. At least 1734 killings of environmental and land defenders took place in a total of 53 countries between 2002 and 2018, most of them occurring in Brazil, the Philippines, Colombia, Honduras, Mexico and Peru. Our multivariate analysis indicates that major country-level determinants of killings include income level, foreign direct investment, dependency on mineral extraction, regime type, frequency of protest movements, and size of Indigenous populations. We suggest that more systematic reporting and analysis of repression – including through subnational level studies for which we provide testable hypotheses – can help protect and support defenders, notably through conflict-sensitive investment policies and greater accountability for abuses. 相似文献
614.
Knowledge is widely considered a key ingredient for the effective and sustainable governance of the environment. In transboundary settings – i.e., where political boundaries cross natural resource system boundaries – there are considerable barriers to knowledge production and use. Resulting knowledge gaps can be barriers to governance. This research examines three case studies in which international river basin organizations, tasked with facilitating cooperation in transboundary river basins, recognized and addressed knowledge gaps to support governance of shared waters. We synthesize across the three case studies to develop a typology of knowledge gaps and the strategies used to address those gaps. In identifying common types of knowledge gaps and the on-the-ground strategies used to fill them, this research provides an important framework for assessing and theorizing knowledge at the transboundary scale, as well as useful recommendations and examples for practitioners seeking to develop that knowledge. 相似文献
615.
利用常规观测、地面自动气象站、多普勒天气雷达、现场灾调及互联网视频等资料,对2018年6月8日发生在广东省佛山市南海区大沥镇的1804号“艾云尼”台风龙卷天气过程进行分析。结果表明:龙卷发生在台风“艾云尼”登陆后前进方向的右后侧,强度为EF1级。高层辐散抽吸、中低空强劲的东南风急流叠加和地面中尺度辐合线的抬升触发作用是其有利的环流背景。对流参数表现为弱的对流有效位能和对流抑制能量、强低层风垂直切变、低抬升凝结高度和大的风暴相对螺旋度。产生龙卷的风暴为低质心微超级单体风暴,龙卷出现在钩状回波的弱回波区内。速度图上中气旋提前龙卷约30 min,临近龙卷发生时中气旋旋转速度增至最强,尺度缩小,底高降至最低,对龙卷预警有一定指示作用。 相似文献
616.
C. Sancho A. MuñozP. González-Sampériz M. Cinta Osácar 《Journal of Arid Environments》2011,75(8):742-751
This work presents a palaeoenvironmental interpretation of the Upper Pleistocene-Holocene sedimentary sequence recorded in the Valsalada saline wetland system (Monegros, Central Ebro Basin). This morphosedimentary system developed on karstified, gypsiferous bedrock and was mainly fed by local saline groundwater. Based on geomorphological, sedimentological, palynological and radiocarbon data, three depositional units have been differentiated: 1) a lacustrine unit, which accumulated under cold/cool and humid environmental conditions at 41-40 kyr cal BP, 2) a fluvial unit that was deposited under arid climatic conditions with cold episodic periods from 14 to 3.5 kyr cal BP, and 3) an alluvial slope unit associated with arid climate with human influence during the Late Roman Period (1.5 kyr cal BP). The morphosedimentary evolution of the Valsalada system is strongly influenced by the geomorphic setting (small catchment with karstic depressions and low gradient slopes on gypsum), the hydrological availability (runoff and groundwater discharges) related to climate variability during the Late Pleistocene-Holocene, and the human activities developed in the area during historical times. The response of the Valsalada system displays a low sensitivity to short-term climatic changes but responds to major long-term climatic conditions, improving the regional paleoenvironmental picture of the Late Quaternary in NE Spain. 相似文献
617.
Two distinct, conflicting, land-use planning paradigms affect drylands: one seeking environmentally sustainable outcomes and one addressing political-demographic concerns. The environmental paradigm is relatively new and is couched in the lexicon of sustainable development, combating desertification and biodiversity conservation. These concerns proscribe planning principles that allow for human settlement in drylands while minimizing its environmental impact. The latter paradigm has a longer history, born in central governments’ desire to secure sovereignty over outlying regions. These concerns result in planning goals that conflict with environmental goals. The environmental paradigm encourages compact development and efficient land-use, while the political-demographic one encourages in-migration of ‘friendly’ populations and the establishment of a physical presence on a maximum amount of land. Using Israel’s Negev Desert and China’s Xinjiang region as case studies, we suggest that successful implementation of sustainable dryland management depends on recognizing the challenge presented by political-demographic planning motivations. As such, successful implementation of environmental planning requires resolution of existing political conflicts. Since drylands are characteristically geographic and demographic frontiers, they are ideal settings in which to study the conflict between environmental and political-demographic goals and they provide an opportunity to better understand how this conflict creates a barrier to sustainable development. 相似文献
618.
近年来环境教育作为自然保护区的一项重要职能工作越来越受到林业主管部门的重视,通过自然保护区平台开展环境教育已成为世界自然保护事业的潮流。广东湛江红树林国家级自然保护区通过中荷合作红树林保护项目的实施,积极探讨环境教育在自然保护区的实践。 相似文献
619.
本文把确定大气稳定度的因子:太阳高度角、云量和风速看作相互独立的变量,并用韦伯分布拟合风频,通过计算三个独立变量的频率的方法计算大气稳定度频率。成都地区实例计算表明,该法与传统的P-T法统计结果十分吻合,但却具有所需资料少,计算工作量小等明显优点,通过对该法的误差进行分析,提出合理的订正方法,得出精确的订正结果。并提出更精确的三参数风频拟合设想。通过与传统P-T法比较,指出了传统P-T法风速分级与实测风速整数取值之间的矛盾,给出了切实可行的解决方法。 相似文献
620.
张端好 《成都信息工程学院学报》1991,(1)
本文将逐步回归和曲线拟合结合起来,设计了一种逐步回归曲线拟合模型,实例分析表明,该模型与逐步回归相比,其拟合误差和预报误差均较小,具有较高的使用价值。 相似文献