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1.
Charles S. Cockell Pascal Lee Gordon Osinski Gerda Horneck Paul Broady 《Meteoritics & planetary science》2002,37(10):1287-1298
Abstract— Asteroid and comet impacts on Earth are commonly viewed as agents of ecosystem destruction, be it on local or global scales. However, for some microbial communities, impacts may represent an opportunity for habitat formation as some substrates are rendered more suitable for colonization when processed by impacts. We describe how heavily shocked gneissic crystalline basement rocks exposed at the Haughton impact structure, Devon Island, Nunavut, Arctic Canada, are hosts to endolithic photosynthetic microorganisms in significantly greater abundance than lesser‐shocked or unshocked gneisses. Two factors contribute to this enhancement: (a) increased porosity due to impact fracturing and differential mineral vaporization, and (b) increased translucence due to the selective vaporization of opaque mineral phases. Using biological ultraviolet radiation dosimetry, and by measuring the concentrations of photoprotective compounds, we demonstrate that a covering of 0.8 mm of shocked gneiss can provide substantial protection from ultraviolet radiation, reducing the inactivation of Bacillus subtilis spores by 2 orders of magnitude. The colonisation of the shocked habitat represents a potential mechanism for pioneer microorganisms to invade an impact structure in the earliest stages of post‐impact primary succession. The communities are analogous to the endolithic communities associated with sedimentary rocks in Antarctica, but because they occur in shocked crystalline rocks, they illustrate a mechanism for the creation of microbial habitats on planetary surfaces that do not have exposed sedimentary units. This might have been the case on early Earth. The data have implications for the microhabitats in which biological signatures might be sought on Mars. 相似文献
2.
With recent changes in the ways that state agencies are implementing their environmental policies, the line between public and private is becoming increasingly blurred. This includes shifts from state-led implementation of environmental policies to conservation plans that are implemented and managed by multi-sectoral networks of governments, the private sector and environmental non-governmental organizations (ENGOs). This paper examines land trusts as private conservation initiatives that become part of neoliberal governance arrangements and partnerships that challenge our conceptions of environmental preservation and democratic participation. The paper starts with an examination of the concept of neoliberalized environmental governance. Next, it addresses the shifting social constructions of property and land in the context of protecting large scale ecosystems. Through a case study of the extension of new environmental governance arrangements on the Oak Ridges Moraine in Ontario, we examine the relationships that have formed between different levels of the state and environmental non-governmental organizations. Finally, we analyze the expansion of land trusts and private conservation initiatives that are predicated on private land ownership and the commodification of nature, the emerging discourses and practices of private conservation, and how these are implicated in the privatization and neoliberalization of nature. 相似文献
3.
Huu Hieu Ho Rudy Swennen Valérie Cappuyns Elvira Vassilieva Gerda Neyens Mustafa Rajabali Tan Van Tran 《Estuaries and Coasts》2013,36(1):203-219
In the present study, the geochemistry of 49 surficial-bed and 101 core sediment samples is investigated to clarify the origin of trace metals in the Cua Luc Estuary and Ha Long Bay, which is a famous World Natural Heritage Site in Vietnam. Moreover, the potential mobility of trace metals is also assessed and their relationship with reference elements (Al, Fe, and Ca) and organic matter is established in order to make recommendations for sediment management and monitor future pollution. Generally, trace metals display higher concentrations in Ha Long Bay compared to the Cua Luc Estuary. However, this is controlled by the distribution of the fine (clay?+?silt) fraction, and hence the concentrations of Al, Fe, Ca, and organic matter (OM). The comparison of concentrations of trace metals (normalized towards Al) between the surficial sediments and the subsurface core sediments based on 137Cs datings indicates that almost all surficial-sediment data fall inside or deviate slightly from the 95 % prediction interval of a background regression line. In addition, as determined by a Community Bureau of Reference three-step extraction, trace metals mainly dominate in the residual fraction (assumed to relate to crystal lattice of primary and secondary minerals), and this fraction does not change much in recent sediment layers. Therefore, trace metals are supposed to be derived from natural bio/geochemical processes and are characterized by a low potential mobility. Consequently, the established linear regression relationships of trace metal vs. Al or multiple regression relationships of trace metal vs. multi-elements (Al, Fe, Ca, and OM) are useful for the prediction of background levels of trace metals in sediments in future pollution monitoring and assessment programs. 相似文献
4.
Gerda Fengler 《Ocean Dynamics》1966,19(3):97-112
Zusammenfassung An Hand von Meßwerten, die gleichzeitig an mehreren Beobachtungspunkten in der Helgoländer Bucht gewonnen wurden, wird die räumliche Homogenität des meteorologischen Feldes über See quantitativ untersucht. Mit Hilfe von reuzkorrelationen und Häufigkeitsanalysen wird festgestellt, daß die an einem Punkt durchgeführten meteorologischen Messungen auf offener See für ein Areal von etwa 70 km und in Küstennähe von etwa 40 km Durchmesser repräsentativ sind.
Unter Verwendung der Diplomarbeit der Verfasserin: G. Beuck [1958]. 相似文献
The homogeneity of the meteorological field above the sea
Summary The results of simultaneous measurements at several observation points in the German Bight are taken for quantitatively investigating the spatial homogeneity of the meteorological field above the sea. Cross correlations and frequency analyses show that the meteorological measurements carried out at one point are representative in the open sea of an area of about 70 km in diameter and near the coast of about 40 kim in diameter.
L'homogénéité du champ météorologique au-dessus de la mer
Résumé En utilisant des mesures obtenues simultanément en plusieurs points d'observation de la baie d'Helgoland, on a étudié quantitativement l'homogénéité dans l'espace du champ météorologique au-dessus de la mer. Au moyen de corrélations croisées et d'analyses de fréquences on a établi que les mesures météorologiques effectuées en un point sont valables au large ou une zone d'environ 70 km de diamètre et, près de terre, pour une zone d'environ 40 km de diamètre.
Unter Verwendung der Diplomarbeit der Verfasserin: G. Beuck [1958]. 相似文献
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6.
Françoise Breton Jaume Clapés Alfons Marquès Gerda K. Priestley 《Ocean & Coastal Management》1996,32(3):153-180
This article offers some reflections on beach management, on the basis of the results of a survey on the recreational use of beaches and beach users' perception, which was carried out in the Metropolitan Region of Barcelona in 1992. The first part outlines the situation of the beaches, recent metropolitan beach policy and the organization of administrative bodies responsible for beach management. Survey objectives and methods are also explained briefly. In the second part, the principal results of the survey are presented and different beaches are compared in an attempt to analyse the types of users, the uses they make and the perception they have of the beaches. The conclusions identify new emerging social needs which demonstrate that new trends in beach management are also needed. Practical recommendations, related to this emerging perception of beaches as natural systems, are suggested. 相似文献
7.
Cornelia MEYER Jörg FRITZ Martin MISGAISKI Dieter STÖFFLER Natalia A. ARTEMIEVA Ulrich HORNEMANN Ralf MOELLER Jean‐Pierre
De VERA Charles COCKELL Gerda HORNECK Sieglinde OTT Elke RABBOW 《Meteoritics & planetary science》2011,46(5):701-718
Abstract– Shock recovery experiments were performed with an explosive set‐up in which three types of microorganisms embedded in various types of host rocks were exposed to strong shock waves with pressure pulse lengths of lower than 0.5 μs: spores of the bacterium Bacillus subtilis, Xanthoria elegans lichens, and cells of the cyanobacterium Chroococcidiopsis sp. 029. In these experiments, three fundamental parameters were systematically varied (1) shock pressures ranging from 5 to 50 GPa, (2) preshock ambient temperature of 293, 233 and 193 K, and (3) the type of host rock, including nonporous igneous rocks (gabbro and dunite as analogs for the Martian shergottites and chassignites, respectively), porous sandstone, rock salt (halite), and a clay‐rich mineral mixture as porous analogs for dry and water‐saturated Martian regolith. The results show that the three parameters have a strong influence on the survival rates of the microorganisms. The most favorable conditions for the impact ejection from Mars for microorganisms would be (1) low porosity host rocks, (2) pressures <10–20 GPa, and (3) low ambient temperature of target rocks during impact. All tested microorganisms were capable of surviving to a certain extent impact ejection in different geological materials under distinct conditions. 相似文献
8.
Dieter Stöffler Gerda Horneck Sieglinde Ott Ulrich Hornemann Charles S. Cockell Ralf Moeller Cornelia Meyer Jean-Pierre de Vera Jörg Fritz Natalia A. Artemieva 《Icarus》2007,186(2):585-588
Bacterial spores (Bacillus subtilis), cyanobacteria (Chroococcidiopsis sp.), and lichen (Xanthoria elegans) embedded in martian analogue rock (gabbro) were exposed to shock pressures between 5 and 50 GPa which is the range of pressures observed in martian meteorites. The survival of Bacillus subtilis and Xanthoria elegans up to 45 GPa and of Chroococcidiopsis sp. up to 10 GPa supports the possibility of transfer of life inside meteoroids between Mars and Earth and it implies the potential for the transfer of life from any Mars-like planet to other habitable planets in the same stellar system. 相似文献
9.
Urban development pressures, preservation of environmentally sensitive areas and regional planning are the focus of current
debates on regionalism in both fast and slow growth regions. Based on two cases—a campaign to preserve ecological integrity
and reduce sprawl on the Oak Ridges Moraine in the Greater Toronto Area and Rochester’s anti-sprawl campaign for regional
equity—the paper examines how two anti-sprawl campaigns brought to the fore alternative constructions of regionalism. In the
fast growing Toronto region, citizen mobilization and upper tier intervention resulted in a legislative base for regionalism.
In the slow growth Rochester region, the city had limited success in gaining regional redistribution. Such divergent outcomes
relate to differences in intergovernmental relations, the city’s influence on the region, receptivity of suburbs to smart
growth, and the potential for values of nature preservation and justice to mobilize regional coalitions. 相似文献
10.
Rural tourism in Spain: an analysis of recent evolution 总被引：6，自引：0，他引：6
The aim of this paper is to analyse the evolution of Rural Tourism1 (RT) in Spain within a European context. The first step is to examine the development of different “models” of RT and trace some experiences of the application of European policy. In order to set the scene and understand this evolution, the collective imagery on which RT is based is also analysed. This is followed by a study of the development of tourist products and services in rural Spain since the 1980s, as diversification of the traditional sun/sand/sea (3S) tourist economy is sought. The analysis underlines the importance of the role of women, and the consequences of the activity for the economy of rural areas. The purpose is to identify differences in the pattern of evolution with more northern European countries, understand their causes and formulate recommendations for future development. 相似文献