Kandidater udgået fra Københavns Universitets Geografiske Institut 1966–71

Christensen, Leif: Faststående og omlejrede Saale-morånelersaflejringer. Et eksempel fra Szdding-området, Vestjylland. Geografisk Tidsskrift 82: 91–94. Copenhagen, Dec. 1, 1982.

In situ clayey till materials on the Skovbjerg Bakkea, western Jutland can be recognized by crop-marks revealing pseudomorphs of ice-wedge polygons in orthogonal, random orthogonal and hexagonal patterns. The tills inside these polygonal patterns have high shear-strength values as measured by vane tests. Remoulded fossil solifluction deposits of till origin reveal stripes and deformed polygonal patterns in the crops. High strength as measured by vane are encountered below fossil solifluction deposits 4 meters below ground.     

Seasonal and Spatial Effects of Wastewater Effluent on Growth,Survival, and Accumulation of Microbial Contaminants by Oysters in Mobile Bay,Alabama

We measured seasonal effects of wastewater treatment plant (WTP) effluent on growth, survival, and accumulation of microbes in oysters near a major WTP in Mobile Bay, AL. Despite higher nutrients near the WTP, seasonal conditions rather than distance affected chlorophyll a concentration and oyster growth. In summer and fall, when oyster growth was higher, δ¹⁵N‰ in oysters near the WTP changed through time to reflect δ¹⁵N‰ in effluent (approx. −4‰). Microbial indicators (male-specific coliphage, fecal coliforms) were highest in oysters near the WTP in all seasons and correlated with δ¹⁵N‰ in fall and summer. Increased riverine discharge and slower acquisition of δ¹⁵N‰ likely confounded correlations in winter/spring. Although we did not detect gross ecological effects of wastewater exposure for oysters, data indicated wastewater-derived particles entered the local food web and accumulated in oysters. These data highlight the importance of using multiple indicators of wastewater exposure and considering both seasonal and spatial effects when defining wastewater influence on a system or species.     

Magnetic and structural study of the Eaux-Chaudes intrusion: understanding the Variscan deformation in the Western Axial Zone (Pyrenees)

The present study provides new magnetic and microstructural data for the Eaux-Chaudes granodioritic massif (Western Axial Zone, Pyrenees) and contributes to the understanding of its geometry, internal structure and emplacement mechanism. Moreover, the geological cross-sections and field data allow to reconstruct the evolution of the whole area from Variscan to Alpine times and to integrate the emplacement of the igneous body in the context of the Variscan orogeny. The Eaux-Chaudes pluton (301?±?9?Ma) is mainly composed by granodiorite, describing a normal compositional zoning and an approximately concentric arrangement that is consistent with the zonation of the low-field magnetic susceptibility. Magnetic foliation is subhorizontal in the inner part of the intrusion and becomes parallel to the petrographical contacts along pluton margins, roughly describing the geometry of the intrusion. Magnetic lineations are dominantly subhorizontal, with E–W to ENE–WSW directional maximum. The general parallelism between Variscan structures of the host rock and the geometry and magmatic fabric of the intrusion reveals a late syn-Variscan emplacement. The tectonic regime registered during magma emplacement is in agreement with an N–S shortening and an E–W stretching direction, consistent with the transpressive regime deduced for other Pyrenean intrusions. Alpine overprint produced a slight tilting in the southern part of the intrusion, but it can be considered that the original Variscan structure is basically unchanged.     

On the utility of identification schemes for digital earth science data: an assessment and recommendations

In recent years, a number of data identification technologies have been developed which purport to permanently identify digital objects. In this paper, nine technologies and systems for assigning persistent identifiers are assessed for their applicability to Earth science data (ARKs, DOIs, XRIs, Handles, LSIDs, OIDs, PURLs, URIs/URNs/URLs, and UUIDs). The evaluation used four use cases that focused on the suitability of each scheme to provide Unique Identifiers for Earth science data objects, to provide Unique Locators for the objects, to serve as Citable Locators, and to uniquely identify the scientific contents of data objects if the data were reformatted. Of all the identifier schemes assessed, the one that most closely meets all of the requirements for an Unique Identifier is the UUID scheme. Any of the URL/URI/IRI-based identifier schemes assessed could be used for Unique Locators. Since there are currently no strong market leaders to help make the choice among them, the decision must be based on secondary criteria. While most publications now allow the use of URLs in citations, so that all of the URL/URI/IRI based identification schemes discussed in this paper could potentially be used as a Citable Locator, DOIs are the identification scheme currently adopted by most commercial publishers. None of the identifier schemes assessed here even minimally address identification of scientifically identical numerical data sets under reformatting.     

Absence of overall feedback in a benthic estuarine community: A system potentially buffered from impacts of biological invasions

Species introductions are among the most dramatic human-induced impacts on aquatic and terrestrial ecosystems around the world. Stability patterns of an estuarine benthic community were investigated through guild interaction models representing the community before and after human-mediated species invasions. The study area was Yaquina Bay, a developed estuary on the central Oregon coast, U.S., where at least 12 species of nonindigenous invertebrates have been inadvertently introduced. Three of the introduced species (the polychaetes Hobsonia florida and Pseudopolydora kempi and the cumacean Nippoleucon hinumensis) are probably among the 10 most abundant invertebrate species in the intertidal benthic community. To estimate effects and potential risks of species introductions on the native community we constructed 2 types of community models based on functional-group interactions, namely, activity guild models and trophic guild models. In both cases we observed that overall feedback has a strong tendency towards zero in pre-invasion and post-invasion models. We generated 12,000 random models of similar size and could not detect this tendency. We suggest that the weak or absent overall feedback in this community may be an ecological property and not an intrinsic property of large systems as such. The reduced response to input from either invertebrate invasions or removal of native top predators, may to some extent buffer the community from such impacts. Alternative guild models suggested increased risk of stability decline in the invaded community even after accounting for potential complexity effects on stabllity. Further species introductions in this intermediately invaded estuary should be avoided.     

Climate change and coastal flooding in Metro Boston: impacts and adaptation strategies

Sea level rise (SLR) due to climate change will increase storm surge height along the 825 km long coastline of Metro Boston, USA. Land at risk consists of urban waterfront with piers and armoring, residential areas with and without seawalls and revetments, and undeveloped land with either rock coasts or gently sloping beachfront and low-lying coastal marshes. Risk-based analysis shows that the cumulative 100 year economic impacts on developed areas from increased storm surge flooding depend heavily upon the adaptation response, location, and estimated sea level rise. Generally it is found that it is advantageous to use expensive structural protection in areas that are highly developed and less structural approaches such as floodproofing and limiting or removing development in less developed or environmentally sensitive areas.     

Spectral line and white-light intensities in the corona in the presence of propagating or standing shocks

The effect of a propagating shock on the Hi L line and the polarization brightness in the inner solar wind region is investigated. We find that the shock produces measurable changes in both and, provided the measurements are made simultaneously, the alteration of the density and velocity across the shock can be derived. For a standing shock the effect on the L line and the white-light radiation is much smaller.