Univ., Diss.--Münster, 1999. / Literaturverz. S. 167 - 182. Nebent.: Zum geologischen Aufbau von NW Spitzbergen.

Th.--Lett. et sci. hum.--Paris--EHESS, 1987. / Bibliogr. p. 317-325.

No description available.

L’Arctique s’est réchauffé rapidement et il y a urgence d’anticiper les effets que cela pourrait avoir sur les protistes à la base de la chaîne alimentaire. Le phytoplancton de l’Océan Arctique inclut les pico- et nano-eucaryotes (0.45-10 μm diamètre de la cellule) et plusieurs de ceux-ci sont des écotypes retrouvés seulement dans l’Arctique alors que d’autres sont introduits des océans plus méridionaux. Alors que les océans tempérés pénètrent dans l’Arctique, il devient pertinent de savoir si ces communautés microbiennes pourraient être modifiées. L’archipel du Svalbard est une région idéale pour observer la biogéographie des communautés microbiennes sous l’influence de processus polaires et tempérés. Bien qu’ils soient géographiquement proches, les régions côtières entourant le Svalbard sont sujettes à des intrusions alternantes de masses d’eau de l’Arctique et de l’Atlantique en plus des conditions locales. Huit sites ont été échantillonnés en juillet 2013 pour identifier les protistes selon un gradient de profondeur et de masses d’eau autour de l’archipel. En plus des variables océanographiques standards, l’eau a été échantillonnée pour synthétiser des banques d’amplicons ciblant le 18S SSU ARNr et son gène pour ensuite être séquencées à haut débit. Cinq des sites d’étude avaient de faibles concentrations de chlorophylle avec des compositions de communauté post-efflorescence dominée par les dinoflagellés, ciliés, des alvéolés parasites putatifs, chlorophycées et prymnesiophytées. L’intrusion des masses d’eau et les conditions environnementales locales étaient corrélées avec la structure des communautés ; l’origine de la masse d’eau contribuant le plus à la distance phylogénétique des communautés microbiennes. Au sein de trois fjords, de fortes concentrations de chlorophylle sous-entendaient des activités d’efflorescence. Un fjord était dominé par Phaeocystis, un deuxième par un clade arctique identifié comme un Pelagophyceae et un troisième par un assemblage mixte. En général, un signal fort d’écotypes liés à l’Arctique prédominait autour du Svalbard. / The Arctic is warming rapidly and there is an urgent need to anticipate the effect this will have on the microbial eukaryotes at the base of the food chain. Arctic Ocean phytoplankton include pico- and nano-eukaryotes (0.45-10 μm cell size), many of these are unique ecotypes found only in the Arctic, but others are advected in from lower latitude oceans. As temperate oceans waters penetrate further into the Arctic, knowledge of whether microbial communities could be displaced is needed. Svalbard is an ideal region to address questions on microbial communities under the influence of polar and temperate processes. Although geographically close, the fjords and offshore regions surrounding Svalbard are subjected to alternate intrusions of Atlantic and Arctic waters in addition to local conditions. Eight sites were surveyed in July 2013 with the aim of identifying microbial eukaryotes at a range of depths and water masses around Svalbard. In addition to standard oceanographic variables, seawater was collected for targeted amplicon libraries based on the 18S SSU rRNA gene and rRNA using high throughput amplicon sequencing. Five of the sites had low chlorophyll concentrations with typical post bloom summer communities; dinoflagellates, ciliates, putative alveolate parasites, chlorophytes and prymnesiophytes. Intrusive water masses and local environmental conditions correlated to community structure, with the origin of the water mass contributing most to the phylogenetic distance of the microbial communities. In three of the fjords, chlorophyll concentrations were high, consistent with a bloom. One fjord was dominated by Phaeocystis, a second by a putative Arctic clade of Pelagophyceae, and the third by mixed species. Overall, a strong signal of Arctic ecotypes prevailed around Svalbard.

Glacier surges are amongst the most dynamic of glaciological phenomena, but their controlling mechanisms remain incompletely understood. Surging glaciers are characterised by cyclical flow instabilities and the rapid transfer of ice to the ablation area, typically resulting in significant mass loss. The High-Arctic archipelago of Svalbard is one of several regions in the northern hemisphere which contain a high-density of surge-type glaciers, variously estimated to be between 13-90% of the total glacier population across the islands. Developing a better understanding of which of these figures, if either, is most realistic is important in the context of glacier dynamics and related contributions of small glaciers and ice caps to sea level change in the immediate future. This study presents detailed assessments of the margins of several known surge-type glaciers in Svalbard in order to update and improve the existing framework by which they are identified, and to provide a foundation for future reassessments of the surge-type glacier population based on distinct ice-sediment-landform assemblages. A range of techniques is utilised, including geomorphological and structural glaciological mapping, sedimentological analysis, basal ice descriptions, and stable isotope analysis. This work provides further insight into diagnostic indicators of surge behaviour preserved in basal ice sequences; provides links between surge dynamics and basal ice sequences, the glaciological structure and the landform record; and investigates the structural and tectonic development of surge-type glaciers. Based on this, surge landsystems are proposed for: (1) small valley glaciers, (2) large land-terminating glaciers, and (3) large tidewater glaciers. It is suggested that these three landsystems, with some variability, broadly characterise the geomorphology of the vast majority of known Svalbard surge-type glaciers and, in conjunction with structural glaciological and basal ice investigations where relevant, may allow previously unknown surge-type glaciers to be identified in the field, from aerial photographs, and on sea floor imagery. This work adds to the existing repertoire of modern analogues and the breadth of surging glacier landsystems, and provides a holistic basis for assessing possible palaeo-surge behaviour within the Quaternary record.

The study was aimed to obtain basic information about the distribution of intestinal parasites of mammals and birds in Svalbard. Faeces of different species were used to detect intestinal parasites. All samples were collected during two seasons and examined by microscopic methods and molecular diagnostic was used for detection of microsporidia, cryptosporidia, coccidia and giardiae.

No description available.

[pt] O caso de Svalbard é ilustrativo da performatividade da Noruega para assegurar a sua soberania no Ártico face à Rússia, tanto em nível bilateral como em duas instâncias multilaterais da política mundial: OTAN e CNUMAD. A insularidade e a distância do arquipélago em relação à Noruega continental, juntamente com a peculiaridade do seu estatuto jurídico, situam essas ilhas em uma encruzilhada vulnerável entre as especulações da Rússia sobre as respostas da OTAN em uma crise (Wither, 2018, p. 28) e as contestações sobre o estatuto das águas extraterritoriais de Svalbard, por um lado, e a performatividade da soberania da Noruega, por outro. A desconstrução factual desta soberania recorre à apresentação dos seguintes dilemas: as disputas marítimas implicadas na incerteza jurídica para a área circundante do arquipélago, a evolução de um percurso democrático local em Svalbard, e a desativação das operações mineiras norueguesas. Todas essas questões parecem relacionar-se entre si, e o imbróglio global das reivindicações contestadas da Noruega de uma plataforma continental contígua em torno do arquipélago condiciona a equação paradoxal que compreende a dupla face da Noruega entre um fornecedor de petróleo e gás e um amigo do ambiente. A deterioração da posição norueguesa de construção de pontes entre o Ocidente e a Rússia por meio da OTAN, face a um dilema de segurança recrudescente, causa uma tensão adicional na performatividade da soberania da Noruega. Ao avaliar a forma como esses acontecimentos se relacionam com a performatividade da soberania da Noruega, a presente investigação pretende traçar subjetividades e percepções de narrativas discursivas que constroem representações, com base no pressuposto de que existem instabilidades da performatividade da soberania norueguesa sob o ponto de vista das suas práticas de segurança e ambientais em relação a Svalbard. Procura-se problematizar essas instabilidades, bem como situar essa análise com base na história conceitual da constituição contextualizada do significado de um vocabulário político chave na Noruega para estes contextos, que é a soberania. A tese é construída sobre a literatura existente que escrutiniza o próprio conceito de soberania como dependente de contexto e de objetivo. O presente estudo baseia-se, portanto, no argumento segundo o qual a performance da Noruega enquanto estado soberano é importante para afirmar a sua soberania por meio da performatividade, tendo em conta as suas políticas e práticas paradoxais. Essa performatividade ganha relevância acrescida face a esses dilemas, na medida em que eles dependem de um resolução política - e não meramente técnica. Nesse sentido, ao conjugar a literatura sobre performatividade com o pós-estruturalismo, é possível evidenciar narrativas e práticas discursivas não só na co-constituição entre discurso, política externa e identidade, mas, em última análise, os mecanismos por meio dos quais a soberania é validada via performatividade, e os modos como essa performatividade se imbrica com práticas discursivas também co-constitutivas da identidade e da política externa. / [en] The case of Svalbard is illustrative of Norway s performativity to ascertain its sovereignty in the Arctic in face of Russia, both bilaterally and in two multilateral instances of world politics: NATO and UNCLOS. The insularity and distance of the archipelago from mainland Norway coupled with the peculiarity of its juridical status situate those islands in a vulnerable crossroads between Russia s speculations over NATO s responses in a crisis (Wither, 2018, p. 28) besides contestations over the status of Svalbard s extraterritorial waters, on the one hand, and Norway s performativity of sovereignty, on the other hand. The factual deconstruction of this sovereignty resorts to the presentation of the following conundrums: the maritime disputes entailed in the legal uncertainty for the area surrounding the archipelago, the evolution of a local democratic course in Svalbard, and the deactivation of Norwegian mining operations. All conundrums seem to relate with one another, and the overarching imbroglio of Norway s contested claims of a contiguous continental shelf around the archipelago conditions the paradoxical equation comprising Norway s double-edged self between an oil and gas supplier and a friend of the environment. The deterioration of Norway s bridge-building stance between the West and Russia via NATO in face of a mounting security dilemma causes extra strain on Norway s performativity of sovereignty. By assessing how those events relate to Norway s performativity of sovereignty, the present research aims at tracing subjectivities and insights of discursive narratives that construct representations, departing from the assumption that there are instabilities of the Norwegian performativity of sovereignty from the standpoint of its security and environment practises in relation with Svalbard. It seeks to problematise these instabilities as well as to situate this analysis based on the conceptual history of the contextualised constitution of meaning of a key political vocabulary in Norway for these contexts, which is sovereignty. It builds on extant literature that scrutinises the very concept of sovereignty as contingent upon context and purpose. The present study therefore bases itself on the argument according to which Norway s performances of statehood are important to assert its sovereignty in view of its paradoxical policies and practices. Norway s performativity of sovereignty gains extra relevance in face of those conundrums insofar as they depend on a political - and not sheerly technical - settlement. In that sense, by combining the literature on performativity with post-structuralism, it is possible to evince narratives and discursive practices not only in the co-constitution among discourse, foreign policy and identity, but ultimately the mechanisms through which sovereignty is validated via performativity and the ways this performativity is imbued with discursive practices also co-constituting identity and foreign policy.

Plankton are generally considered good indicators for ocean climate variability, but plankton data from the Arctic are still comparatively scarce. Due to this scarcity of information, the prevalence of vertical migration behaviour at high latitude is still debated. Atlantic inflow is a key process governing biological diversity in the Arctic Ocean, and the location of the Svalbard archipelago makes it an ideal study area to monitor this inflow. Comparing the zooplankton community within the fjords of Svalbard at various latitudes allowed us to assess the influence of Atlantic inflow and any subsequent changes in zooplankton composition that may have implications for higher trophic levels. Using sediment traps deployed on oceanic moorings, Chapter 3 of this thesis analysed long term observations from sea-ice dominated Rijpfjorden for the first time, and compared the zooplankton to Atlantic Water influenced Kongsfjorden. Chapters 4 and 5 investigated the spatial relevance of our moored observations using shipboard observations, and chapters 6 and 7 present observations of vertical migration across a range of conditions. Kongsfjorden was dominated by Calanus copepods associated with Arctic and Atlantic water, and strongly influenced by Atlantic Water advection. Rijpfjorden was largely influenced by sea-ice formation with higher proportional abundances of macrozooplankton species. Advection brought Atlantic associated species into Rijpfjorden during warmer years. Prevailing hydrology and bathymetry were highlighted as factors forcing zooplankton distribution, while advection was identified as responsible for much of the observed small scale spatial variation amongst weaker swimmers. At an aggregation scale of 0.5 nautical miles, zooplankton distribution was highly patchy and moored observations could only be reliably expanded outwards to a maximum of 1 nautical mile. Low amplitude diel vertical migration (especially by younger copepodids) was identified in surface waters when a food source was available. These observations must be considered within the dynamic framework of advection highlighted by this thesis.

Glaciers and ice caps (GIC) are central parts of the hydrological cycle, are key to understanding regional and global climate change, and are important contributors to global sea level rise, regional water resources and local biodiversity. Multispectral (visible and near-infrared) remote sensing has been used for studying GIC and their changing characteristics for several decades. Glacier surfaces can be classified into a range of facies, or zones, which can be used as proxies for annual mass balance and also play a significant role in understanding glacier energy balance. However, multispectral sensors were not designed explicitly for snow and ice observation, so it is not self-evident that they should be optimal for remote sensing of glaciers. There are no universal techniques for glacier surface classification which have been optimized with in situ reflectance spectra. Therefore, the roles that the various spectral, spatial, and radiometric properties of each sensor play in the success and output of resulting classifications remain largely unknown. Therefore, this study approaches the problem from an inverse perspective. Starting with in situ reflectance spectra from the full range of surfaces measured on two glaciers at the end of the melt season in order to capture the largest range of facies (Midtre Lovénbreen, Svalbard & Langjökull, Iceland), optimal wavelengths for glacier facies identification are investigated with principal component analysis. Two linear combinations are produced which capture the vast majority of variance in the data; the first highlights broadband albedo while the second emphasizes the difference in reflectance between blue and near-infrared wavelengths for glacier surface classification. The results confirm previous work which limited distinction to snow, slush, and ice facies. Based on these in situ data, a simple, and more importantly completely transferrable, classification scheme for glacier surfaces is presented for a range of satellite multispectral sensors. Again starting with in situ data, application of relative response functions, scaling factors, and calibration coefficients shows that almost all simulated multispectral sensors (at certain gain settings) are qualified to classify glacier accumulation and ablation areas but confuse classification of partly ash-covered glacier surfaces. In order to consider the spatial as well as the spectral properties of multispectral sensors, airborne data are spatially degraded to emulate satellite imagery; while medium-resolution sensors (~20-60 m) successfully reproduce high-resolution (2 m) observations, low-resolution sensors (i.e. 250 m+) are unable to do so. These results give confidence in results from current sensors such as ASTER and Landsat ETM+ as well as ESA’s upcoming Sentinel-2 and NASA’s recently launched LDCM. In addition, images from the Landsat data archive are used to classify glacier facies and calculate the albedo of glaciers on the Brøgger Peninsula, Svalbard. The time series is used to observe seasonal and interannual trends and investigate the role of melt-albedo feedback in thinning of Svalbard glaciers. The dissertation concludes with recommendations for glacier surface classification over a range of current and future multispectral sensors. Application of the classification schemes suggested should help to improve the understanding of recent and continuing change to GIC around the world.