Metal fluxes through the Strait of Gibraltar: the influence of the Tinto and Odiel rivers (SW Spain)     

Franoise Elbaz-Poulichet  Nicholas H. Morley  Jean-Marie Beckers  Philippe Nomerange 《Marine Chemistry》2001,73(3-4)

A large set of new data concerning dissolved metal concentrations has been acquired in the Gulf of Cadiz and in the Strait of Gibraltar from 1996 to 1999. These data, associated with models (hydrodynamic, tracer advection–dispersion and mixing), have been used to assess the influence of rivers draining the South Iberian Pyrite Belt on the Gulf of Cadiz and on the Atlantic inflow in the Strait of Gibraltar.Metal concentrations in surface waters from the Gulf of Cadiz are maximal near the mouth of the Tinto/Odiel rivers with values exceeding 50 nmol/kg (Mn), 5 nmol/kg (Ni), 30 nmol/kg (Cu), 100 nmol/kg (Zn), 0.9 nmol/kg (Cd) and 45 nmol/kg (As). From the Tinto/Odiel river, a plume of contamination follows the coast in the direction of the Strait of Gibraltar. The computation of a tracer advection–dispersion model confirms that the coastal currents carry the metals discharged from the Tinto and Odiel to the Strait of Gibraltar.From temperature–salinity and metal–salinity plots, four water masses can be recognised in the Gulf of Cadiz and in the Strait of Gibraltar: North Atlantic Surface Water (NASW), North Atlantic Central Water (NACW) and metal-enriched Spanish Shelf Waters from the Gulf of Cadiz (SSW). The Mediterranean Outflow Water (MOW) is also clearly seen at depths greater than 300 m.The chemical characteristics of these various water masses have been used in a mixing model to evaluate their relative contribution to the Atlantic inflow through the Strait of Gibraltar. These contributions are seasonally variable. In June 1997, the contribution was: 80±20%, 5±5% and 15±10% for NASW, NACW and SSW, respectively. In September, the SSW contribution was apparently negligible.Finally, these relative contributions allow the evaluation of the metal fluxes in the Strait of Gibraltar. The presence of SSW in the Strait increases the metal flux to the Mediterranean Sea by a factor of 2.3 (Cu), 2.4 (Cd), 3 (Zn) and 7 (Mn). It does not modify significantly As and Ni fluxes.  相似文献   

A graph-based algorithm to define urban topology from unstructured geospatial data     

J.-P. de Almeida  J.G. Morley  I.J. Dowman 《International journal of geographical information science》2013,27(8):1514-1529

Interpretation and analysis of urban topology are particularly challenging tasks given the complex spatial pattern of the urban elements, and hence their automation is especially needed. In terms of the urban scene meaning, the starting point in this study is unstructured geospatial data, i.e. no prior knowledge of the geospatial entities is assumed. Translating these data into more meaningful homogeneous regions can be achieved by detecting geographic features within the initial random collection of geospatial objects, and then by grouping them according to their spatial arrangement. The techniques applied to achieve this are those of graph theory applied to urban topology analysis within GIS environment. This article focuses primarily on the implementation and algorithmic design of a methodology to define and make urban topology explicit. Conceptually, such procedure analyses and interprets geospatial object arrangements in terms of the extension of the standard notion of the topological relation of adjacency to that of containment: the so-called ‘containment-first search’. LiDAR data were used as an example scenario for development and test purposes.  相似文献   

Mapping Collaboration in Open Source Geospatial Ecosystem     

Jianhua Shao  George Kuk  Suchith Anand  Jeremy G. Morley  Mike J. Jackson  Tyler Mitchell 《Transactions in GIS》2012,16(4):581-597

Over the last decade, there has been a tremendous growth and exploitation of open source geospatial software and technologies. A combination of factors is driving this momentum, including the contributions made by hundreds of developers and the leading role played by the Open Source Geospatial Foundation (OSGeo), aiming primarily to support and promote the collaborative development of open source geospatial technologies and data. This article seeks to map out the social history of collaborative activities within the OSGeo ecosystem. We used the archival logs of developers' contributions, specifically looking for boundary spanning activities where contributions crossed multiple projects. The analysis and visualization of these activities allow us to have a better understanding of the role of boundary spanning in the resourcing of each project, the incubation mechanism advocated by OSGeo, and the significance of the social interrelatedness among projects. The data consisted of the subversion (SVN) commit history made by individual developers in the programming code repository. We applied several network analytical and visualization techniques to explore the data. Our findings indicate that more than one in seven developers spanned multiple projects which potentially had the effects of shaping the projects' directions, and increased knowledge flow and innovation. In addition, the OSGeo's incubation mechanism provided an important encouragement for boundary spanning and increased knowledge sharing. By studying the social history of contributions, further tools can be developed in future to assist tracking of the social history, and make developers mindful of the significance of the interdependence among projects and hence continuously contribute to the health of the OSGeo ecosystem.  相似文献   

Public perceptions on coastal erosion in the Maltese Islands: a case study of St George’s Bay (St Julians) and Pretty Bay (Birżebbuġa)     

Farrugia  Maria Theresa 《Natural Hazards》2017,86(2):587-604

With 60% of the world’s population living within the coastal zone, coastal erosion is considered as a global problem. The coasts of the Maltese Islands hold a variety of formations resulting from coastal erosion. Beach nourishment is one of the protective measures taken against coastal erosion. This paper focuses on two of the nourished beaches within the Maltese Islands, St George’s Bay (St Julians) and Pretty Bay (Birżebbuġa), that have undergone extensive sand augmentation during the past decades and looks at the extent of how coastal erosion and beach replenishment may have influenced public perception. Through a triangulation of interviews, it seeks to understand the views of beach users, researchers, representatives, and beach managers. It presents divergences in interviewee opinions and ideas on St George’s Bay and Pretty Bay and illustrates that public perception tends to reflect the type of urban area surrounding each replenished beach. Recommendations and suggestions are also presented to promote awareness towards coastal processes and their impacts.

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Continental rift-setting and evolution of Neoproterozoic Sindreth Basin in NW-India     

Stefan Schöbel  Kamal K Sharma  Thorsten Hörbrand  Theresa Böhm  Ines Donhauser  Helga de Wall 《Journal of Earth System Science》2017,126(6):90

The Neoproterozoic Sindreth Basin, NW India, and its surrounding area represent a half graben structure situated between the undeformed Malani Igneous Suite (MIS) in the west and a corridor of coeval Cryogenian ductile deformation, anatexis and granite intrusion in the east. The main lithologies observed in the basin are conglomerate, fanglomerate, debris flow and lake deposits derived from a nearby continental provenance, intercalated with concurrent mafic and felsic lava flows. Based on geological traverses across the strike of the basin, we propose a three-fold classification comprising Lower Clastic Unit and an Upper Clastic Unit and a Bimodal (basalt–rhyolite) Volcanic Unit separating the two. Tilting due to basin inversion and faulting has been observed; however, the rocks are unmetamorphosed and show undisturbed primary sedimentary features. The stratigraphic record of the basin is characteristic for deposition and magmatism in a fault-related continental setting. Implications of the findings have been discussed in the context of Neoproterozoic crustal dynamics in NW India. This study provides conclusive evidence for a continental setting for Sindreth Basin evolution and contests the recent models of active subduction setting (either back-arc basin or accretionary sediments over a subduction zone).  相似文献   

Discovering stellar core collapse events using satellite-born RF detectors     

P. D. Morley  David W. Eastin 《Astrophysics and Space Science》2008,314(4):275-279

Previous research has shown that a massive electromagnetic pulse (MEMP) is the precursor to type II stellar core collapse events. While Earth’s ionosphere makes ground-based detection of this RF (radio frequency) electromagnetic pulse improbable, it can be readily observed by satellite-born detectors. The expected radius of detection using presently available COTS (commercial-off-the-shelf) equipment is 2.67 billion light-years. A new class of astronomical objects is predicted to exist.  相似文献   

Responses of lake phytoplankton to micronutrient enrichment: a study in two New Zealand lakes and an analysis of published data     

Theresa M. Downs  Marc Schallenberg  Carolyn W. Burns 《Aquatic Sciences - Research Across Boundaries》2008,70(4):347-360

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The Use of Storytelling for Understanding Women's Desires to Tan: Lessons from the Field     

Theresa Garvin  Kathleen Wilson 《The Professional geographer》1999,51(2):297-306

This paper presents reflections on a research project in women's health, providing both substantive findings surrounding tanning and social status and methodological recommendations for future research. The project under review utilized a picture-elicited storytelling method to: a) understand how women link tanned, bronzed skin to health, status, and attractiveness; and b) test the effectiveness of picture-elicited storytelling as a research method. The project found that, when tanning, women use their bodies to inscribe the social norm of the bronzed aesthetic. While women indicate considerable knowledge of the health dangers of tanning, they continue to link tanned skin to beauty, status, and attractiveness. Further, the research project found that the use of picture-elicited storytelling as a method is potentially powerful but requires considerable attention to concerns of power and representation on the part of the research team.  相似文献   

Zinc concentrations in marine macroalgae and a lichen from western Ireland in relation to phylogenetic grouping, habitat and morphology     

Stengel DB  Macken A  Morrison L  Morley N 《Marine pollution bulletin》2004,48(9-10):902-909

Zinc concentrations in 19 species of marine macroalgae and a lichen from western Ireland (Spiddal, Co. Galway) were analysed by atomic absorption spectrophotometry. Algae were collected from a single site but occupied different shore levels and belonged to distinct phylogenetic groupings and to different (previously recognised) morphological groups. Concentrations ranged from 15-115 microg g(-1) dry weight. The greatest variation in concentration occurred amongst the red algal species, containing both maximum and minimum concentrations. Zn concentrations in brown and green algae were generally lower than those in red algae. When grouped according to thallus morphology, thin, branched sheets (which consisted mainly of red algae) contained the highest Zn concentrations. In filamentous algae, Zn levels were higher than in thick-leathery or coarsely branched algae. However, all green algal species examined had similar Zn concentrations, despite their different morphologies. In brown algae, the highest Zn levels were detected in mid-shore fucoids (Fucus vesiculosus and Fucus serratus), while thicker, subtidal and low-shore brown algae (Laminaria digitata, Halydris siliquosa) exhibited lower Zn concentrations. The lowest Zn concentrations were detected in high-intertidal species (Fucus spiralis, Pelvetia canaliculata), the only marine lichen examined (Ramalina siliquosa) and a red crustose alga (Corallina officinalis). In all morphological groups, red algal representatives contained relatively higher levels of Zn, the exception being Corallina officinalis. Zn levels in 4 species from a second, estuarine site in Galway Bay exhibited the same relative differences amongst species, but were all consistently higher than in algae from Spiddal. It is concluded that Zn accumulation in macroalgae is closely related to ecological growth strategies, following a functional-form model. However, the phylogenetic origin of species which determines carbohydrate and phenol composition, and responses to ambient environmental conditions ultimately determine, the availability of binding sites for polyvalent cations.  相似文献   

Faunal migrations since the cretaceous period     

A. Morley Davies 《Proceedings of the Geologists' Association. Geologists' Association》1929,40(4):307-327

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