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Retreating glaciers are leaving behind deglaciated areas, lacking biological life, presenting opportunities for specialist species to colonize. Lichens possess the ability, due to the symbiosis with nitrogen fixating photobionts, to colonize these deglaciated areas even in harsh environments like in the European Alps or maritime Antarctica. I hypothesized that there are no differences in lichen species richness, diversity, and evenness in deglaciated areas within four Alpine glaciers as well as four Alpine glaciers and one Antarctic glacier, yet there are differences between four successional zones in the same areas. Furthermore, there are no lichen species that colonize both the European Alps and Antarctica. Study sites consisted of Morteratsch Glacier, Gaisbergferner Glacier, Rötkees Glacier and Pasterze Glacier in the Alps as well as McLeod Glacier on Signy Island, South Orkney Islands, Antarctica. Four indexes were calculated: alpha diversity, Shannon Index, Menhinicks Index and Pielou Index and compared with Anova and Kruskal-Wallis tests. The results showed no significant differences for the species richness, diversity, and evenness of lichen species for the Alpine and Antarctic study sites yet there were differences found between the successional zones. Four lichen species were found in all the Alpine study sites, yet no common lichen species were present in the Alpine and Antarctic sites. Environmental conditions differ between the Alps and Antarctica which is reflected in the anomaly of the Menhinicks Index and furthermore, sexual, or vegetative reproduction influences lichen species present. The successional zones did not follow the chronological order since deglaciation which might reflect an increase in species competition as vegetation develops under time. Lichen species are understudied, and further research might not only give insights into inner processes in lichens but also about how to survive in extreme environments. / Glaciärer som drar sig tillbaka lämnar efter sig områden som saknar biologiskt liv, vilket skapar möjlighet för specialister att inta dessa områden. Lavar har förmågan att kolonisera sådana isfria områden på grund av sin symbios med kväve-fixerande fotobionter även om miljöerna är hårda som i den europeiska Alperna eller det maritima Antarktis. Mina hypoteser är att det inte finns skillnader i lavarnas artrikedom, diversitet och jämnhet i de områden som nyligen blivit isfria inom fyra alpina glaciärer samt mellan de fyra alpina glaciärerna och en antarktisk glaciär men att det finns skillnader mellan fyra successionala zoner i samma områden. Vidare finns det inga lavarter som koloniserar båda Alperna och Antarktis. Studieområdena bestod av: Morteratsch-glaciär, Gaisbergferner-glaciär, Rötkees-glaciär och Pasterze-glaciär i Alperna samt McLeod-glaciär på Signyön, Syd Orkneyöarna, Antarktis. Fyra index beräknades: alfa diversitet, Shannon Index, Menhinicks Index och Pielou Index och jämfördes med Anova och Kruskal-Wallis testerna. Resultaten visade inga signifikanta skillnader för artens rikedom, mångfald och jämnhet av lavarterna för lavarter i alpina och antarktiska studieområdena, men det fanns skillnader mellan de successionella zonerna. Fyra lavarter hittades på alla alpina studieplatser, men inga gemensamma lavarter fanns på de alpina och antarktiska platserna. Miljöförhållanden skiljer sig mellan Alperna och Antarktis, vilket syns i avvikelsen av Menhinicks Index och dessutom påverkar sexuell eller asexuell reproduktion förekomsten av lavarter. Successionszonerna följde inte den kronologiska ordningen efter reträtten av glaciärerna vilket kan återspegla en ökning av artkonkurrensen när vegetationen utvecklar sig över tiden. Lavarna är underforskade och ytterligare forskning kan ge upplysningar i interna processer men även insikter kring hur överlevnad blir säkerställd i extrema miljöer.

Thesis (PhD)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: This study addresses a little-known but important part of South Africa’s history: its involvement with the sub-Antarctic and Antarctic in the twentieth century. It has a three-fold approach. Firstly, it provides insight into the motives driving South Africa’s investment in the region, from the first call for a South African Antarctic expedition in 1919 to the post-apartheid recommitment to the South African Antarctic Programme. Interrogating of the reasons behind South Africa’s activities in this region – including those that failed –throws into relief broader issues about how and where South Africa saw itself in the geopolitical order. As such, this dissertation is situated within a body of Antarctic scholarship that seeks to subvert the prevailing homogenising narrative of the continent as simply the preserve of scientists and heroes. In particular, it investigates how tropes of imperialism and nationalism functioned in these remote corners of the world. Secondly, this dissertation investigates how changing perceptions of the extreme environment of Antarctica, and specifically the Prince Edward Islands, can add to our understanding of environmental history. It also shows how the values projected onto and invested in the environment as ‘nature’ changed over time. Thirdly, it takes into account the humans that were South Africa’s presence in the region and how the underlying patterns in the fabric of South African society, including race and gender, crystalized on the Antarctic continent. / AFRIKAANSE OPSOMMING: Hierdie studie is gerig op ʼn minder bekende, maar belangrike aspek van Suid-Afrika se geskiedenis: die land se betrokkenheid by die sub-Antarktiese gebied en Antarktika in die twintigste eeu. Die studie volg van ʼn drie-ledige benadering. Eerstens, verskaf dit insig in die dryfvere agter Suid-Afrika se investering in die streek – vanaf die eerste beroep op ʼn Suid-Afrikaanse Antarktiese ekspedisie in 1919, tot die post-apartheid regering se herverbintenis tot die Suid-Afrikaanse Antarktiese program. Die ondersoek na die redes vir Suid-Afrika se aktiwiteite in die streek – insluitend dié wat misluk het – bring breër kwessies oor Suid-Afrika se selfbeskouing in die wêreld se geopolitieke orde, na vore. Hierdie studie word binne ʼn kritiese raamwerk van navorsing oor Antarktika geplaas. Dié raamwerk streef daarna om die oorheersende homogene beeld van die kontinent as die eksklusiewe grondgebied van wetenskaplikes en helde, onder die soeklig te stel. In die besonder stel dit ondersoek in na hoe imperialisme en nasionalisme in hierdie verafgeleë uithoeke van die aarde versinnebeeld is. Tweedens, ondersoek hierdie studie hoe veranderende persepsies van Antarktika - en veral die Prins Edward eilande - se uiterste omgewing tot ons begrip van omgewingsgeskiedenis kan bydra. Dit dui ook aan die mate waartoe bestaande waardes wat op die omgewing as ‘natuur’ geprojekteer en gevestig is, mettertyd verander het. Die derde benadering neem die mense wat Suid-Afrika se teenwoordigheid verpersoonlik het in aanmerking - en hoe die onderliggende patrone in die Suid-Afrikaanse samelewing, insluitend ras en geslag, op die Antarktiese kontinent uitgekristalliseer het.

Approved for public release, distribution is unlimited / This study examines Southern Hemisphere mid-latitude wave variations connected to the Antarctic Oscillation (AAO) to establish connections with the 15- to 25-day wave activity in the western North Pacific monsoon trough region. The AAO index defined from the leading empirical orthogonal functions of 700 hPa height anomalies led to seven distinct circulation patterns that vary in conjunction with the 15- to 25-day monsoon trough mode. For nearly one half of the significant events the onset of 15- to 25-day monsoon trough convective activity coincided with a peak negative AAO index and the peak in monsoon trough convection coincided with a peak positive index. The remaining events either occur when the AAO is not significantly varying or when the AAO-related Southern Hemisphere mid-latitude circulations do not match 15- to 25-day transitions. When a significant connection occurs between the Southern Hemisphere mid-latitude circulations related to the AAO and the 15- to 25-day wave activity in the western North Pacific monsoon trough, the mechanism is via equatorward Rossby-wave dispersion. When wave energy flux in the Southern Hemisphere is directed zonally, no connection is established between the AAO and the alternating periods of enhanced and reduced convection in the western North Pacific monsoon trough. / Captain, United States Air Force

This thesis describes strategies for and examples ofcellulose fiber modification.The ability of an engineered biocatalyst, acellulose-binding module fused to theCandida antarcticalipase B, to catalyze ring-openingpolymerization of e-caprolactone in close proximity tocellulose fiber surfaces was explored. The water content in thesystem was found to regulate the polymer molecular weight,whereas the temperature primarily influenced the reaction rate.The hydrophobicity of the cellulose sample increased as aresult of the presence of surface-deposited polyester. A two-step enzymatic method was also investigated. Here,Candida antarctica lipase B catalyzed the acylation ofxyloglucan oligosaccharides.The modified carbohydrates werethen incorporated into longer xyloglucan molecules through theaction of a xyloglucan endotransglycosylase. The modifiedxyloglucan chains were finally deposited on a cellulosesubstrate. The action ofCandida antarcticalipase B was further investigated inthe copolymerization of e-caprolactone and D,L-lactide.Copolymerizations with different e-caprolactone-to-D,L-lactideratios were carried out. Initially, the polymerization wasslowed by the presence of D,L-lactide. During this stage,D,L-lactide was consumed more rapidly than ε-caprolactoneand the incorporation occurred dimer-wise with regard to thelactic acid units. Morphological studies on wood fibers were conducted using asol-gel mineralization method. The replicas produced werestudied, without additional sample preparation, by electronmicroscopy and nitrogen adsorption. Information concerning thestructure and accessibility of the porous fiber wall wasobtained. Studies of never-dried kraft pulp casts revealedmicro-cavities and cellulose fibrils with mean widths of 4.7(±2) and 3.6 (±1) nm, respectively. Finally, cationic catalysis by simple carboxylic acids wasstudied. L-Lactic acid was shown to catalyze the ring-openingpolymerization of ε-caprolactone in bulk at 120 °C.The reaction was initiated with methylß-D-glucopyranoside, sucrose or raffinose, which resultedin carbohydrate-functionalized polyesters. The regioselectivityof the acylation was well in agreement with the correspondinglipase-catalyzed reaction. The polymerization was alsoinitiated with a hexahydroxy-functional compound, whichresulted in a dendrimer-like star polymer. The L-lactic acidwas readily recycled, which made consecutive reactions usingthe same catalyst possible. Keywords:Candida antarcticalipase B, cationic catalysis,cellulose-binding module, dendrimer, enzymatic polymerization,fiber modification, silica-cast replica, sol-gelmineralization, organocatalysis, xyloglucanendotransglycosylase

L'augmentation du bilan de masse en surface de la calotte polaire Antarctique causée par celle des chutes de neige est la seule contribution négative à l'élévation du niveau de mer attendue dans le courant du 21ème siècle dans le cadre du réchauffement climatique causé par les activités humaines. La régionalisation dynamique de projections climatiques issues de modèles couplés océans-atmosphère est la méthode la plus couramment utilisée pour estimer les variations futures du climat Antarctique. Néanmoins, de nombreuses incertitudes subsistent suite à l'application de ces méthodes, en particulier en raison des biais conséquents sur les conditions océaniques de surface et sur la circulation atmosphérique aux hautes latitudes de l’Hémisphère Sud dans les modèles couplés.Dans la première partie de ce travail, différentes méthodes de corrections de biais des conditions océanique de surface ont été évaluées. Les résultats ont permis de retenir une méthode quantile-quantile pour la température de surface de l'océan et une méthode d'analogues pour la concentration en glace de mer. En raison de la forte sensibilité du climat future Antarctique aux variations de couverture de glace de mer dans l'Océan Austral, les conditions océaniques issues de deux modèles couplés, NorESM1-M et MIROC-ESM, présentant des diminutions d’étendues de glace de mer hivernales largement différentes (-14 et -45%) ont été retenues. Les conditions océaniques provenant d'un scénario RCP8.5 de ces deux modèles ont été corrigées afin de forcer le modèle atmosphérique global ARPEGE.Par la suite, ARPEGE a été utilisé dans une configuration grille-étirée, permettant d'atteindre une résolution horizontale de 40 kilomètres sur l'Antarctique. Il a été contraint aux limites par les conditions océaniques de surface observées et celles issues des simulations historiques des modèles NorESM1-M et MIROC-ESM pour la période récente (1981-2010). Pour la fin du 21ème siècle (2071-2100), les forçages océaniques originaux et corrigés issus de ces deux derniers modèles ont été utilisés. L'évaluation pour le présent a permis de mettre en évidence, la capacité du modèle ARPEGE de reproduire le climat et le bilan de masse de surface Antarctique ainsi que la persistance d'erreurs substantielles sur la circulation atmosphérique y compris dans la simulation forcée par les conditions océaniques observées. Pour le climat futur, l'utilisation des forçages océaniques MIROC-ESM corrigés a engendré des augmentations supplémentaires significatives à l'échelle continentale pour les températures hivernales et le bilan de masse annuel.Enfin, ARPEGE a été corrigé en ligne, à l'aide d'une climatologie des termes de rappel du modèle issus d'une simulation guidée par les réanalyses climatologiques. L'application de cette méthode sur la période récente a très largement amélioré la modélisation de la circulation atmosphérique et du climat de surface Antarctique. L'application pour le climat futur suggère des augmentations de températures (+0.7 à +0.9 C) et de précipitations (+6 à +9%) supplémentaires par rapport à celles issues des scénarios réalisés sans correction atmosphérique. Le forçage de modèles climatiques régionaux ou de dynamique glaciaire avec les scénarios ARPEGE corrigés est à explorer au regard des impacts potentiellement importants pour la calotte Antarctique et sa contribution à l'élévation du niveau des mers. / The increase of the Antarctic ice-sheet surface mass balance due to rise in snowfall is the only expected negative contribution to sea-level rise in the course of the 21st century within the context of global warming induced by mankind. Dynamical downscaling of climate projections provided by coupled ocean-atmosphere models is the most commonly used method to assess the future evolution of the Antarctic climate. Nevertheless, large uncertainties remain in the application of this method, particularly because of large biases in coupled models for oceanic surface conditions and atmospheric large-scale circulation at Southern Hemisphere high latitudes.In the first part of this work, different bias-correction methods for oceanic surface conditions have been evaluated. The results have allowed to select a quantile-quantile method for sea surface temperature and an analog method for sea-ice concentration. Because of the strong sensitivity of Antarctic surface climate to the variations of sea-ice extents in the Southern Ocean, oceanic surface conditions provided by two coupled models, NorESM1-M and MIROC-ESM, showing clearly different trends (respectively -14 and -45%) on winter sea-ice extent have been selected. Oceanic surface conditions of the ``business as usual" scenario (RCP8.5) coming from these two models have been corrected in order to force the global atmospheric model ARPEGE.In the following, ARPEGE has been used in a stretched-grid configuration, allowing to reach an horizontal resolution around 40 kilometers on Antarctica. For historical climate (1981-2010), the model was driven by observed oceanic surface conditions as well as by those from MIROC-ESM and NorESM1-M historical simulation. For late 21st century (2071-2100), original and bias corrected oceanic conditions from the latter two model have been used. The evaluation for present climate has evidenced excellent ARPEGE skills for surface climate and surface mass balance as well as large remaining errors on large-scale atmospheric circulation even when using observed oceanic surface conditions. For future climate, the use of bias-corrected MIROC-ESM oceanic forcings has yielded an additionally significant increase in winter temperatures and in annual surface mass balance at the continent-scale.In the end, ARPEGE has been corrected at run-time using a climatology of tendency errors coming from an ARPEGE simulation driven by climate reanalyses. The application of this method for present climate has dramatically improved the modelling of the atmospheric circulation and antarctic surface climate. The application for the future suggests significant additional warming (~ 0.7 to +0.9 C) and increase in precipitation (~ +6 to +9 %) with respect to the scenarios realized without atmospheric bias correction. Driving regional climate models or ice dynamics model with corrected ARPEGE scenarios is to explored in regards of the potentially large-impacts on the Antarctic ice-sheet and its contribution to sea-level rise.