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

Il existe actuellement des différends frontaliers entre les États circumpolaires-Nord qui entravent la bonne gouvernance de la région. Afin d'identifier des pistes de solution pour améliorer la gouvernance en Arctique et faciliter la coopération, nous analysons le processus qui a mené, à l'autre pôle, à la création du Traité sur l’Antarctique de 1959. Nous utilisons une approche néolibérale institutionnelle comme cadre théorique ainsi qu’une méthodologie basée sur le traçage de processus. Nous avons identifié quatre variables (les intérêts des États, le contexte politique, le leadership, et l’Année géophysique internationale [AGI]) que nous avons étudiés au cours de trois périodes historiques et dont l’évolution a contribué à la formation du régime antarctique. Les étapes menant à l'élaboration d'un régime identifié dans la théorie institutionnaliste dynamique de Frischmann s'appliquent aux différentes périodes que nous avons déterminées. La première période historique correspond à l'identification du problème d'interdépendance. Les États ont d’abord tenté d’assouvir leurs intérêts particuliers envers le continent antarctique par l’intermédiaire de stratégies individuelles. Le statut imprécis du continent antarctique caractérisé par des revendications territoriales conflictuelles, la volonté des superpuissances d’effectuer d’éventuelles revendications territoriales et le leadership exercé par les États-Unis ont toutefois permis de faire évoluer les États vers des stratégies coopératives. La deuxième période historique correspond à l'étape de la négociation de l’entente. Le leadership d’un groupe de scientifiques et des États-Unis ainsi que le contexte politique de la Guerre froide ont favorisé la cohésion des États intéressés par les affaires antarctiques et leur investissement dans une coopération multilatérale souple dans le cadre d’un événement ponctuel, l’AGI. La troisième période correspond à la mise en oeuvre de l’entente, soit l’AGI. Lors de cet événement, une entente tacite, un engagement d’honneur, qui suspendait les considérations territoriales en Antarctique, a été respectée par les parties. La coopération dans le cadre de l’AGI s’est avérée un succès. Les États se sont montrés satisfaits des gains que comportait la coopération scientifique dans un environnement pacifique. L’AGI a permis aux États d’expérimenter la coopération multilatérale et d’observer le comportement des autres participants au sein de l’institution. En raison de la satisfaction des États vis-à-vis la coopération dans le cadre de l'entente souple, l'élaboration du traité de 1959 a été facilitée. Notre étude nous a permis d’identifier des éléments clefs qui ont favorisé la formation du régime antarctique et qui pourraient servir d’inspiration pour l'élaboration de futurs régimes. La présence d’un leadership tout au long du processus a permis de promouvoir les avantages de la coopération sous différentes formes et de renforcer les relations entre les États présents dans les affaires antarctiques. La réalisation d'une entente souple dans le cadre de l'AGI, centrée autour des intérêts communs aux parties, comprenant un engagement d’honneur, permettant de mettre de côté les points de discorde, ont aussi été des points centraux dans la réussite et la poursuite de la coopération au-delà de l’AGI. Cette approche graduelle allant du droit souple vers le droit contraignant est sans aucun doute l’élément le plus important ayant facilité le rapprochement des différentes parties et éventuellement la création du Traité sur l’Antarctique. / There are currently border disputes between North circumpolar states that impede the good governance of the region. In order to identify possible solutions for improving the governance in the Arctic and to facilitate cooperation, we analyze the process that, at the other pole, led to the creation of the 1959 Antarctic Treaty. We use a neoliberal institutional approach as a theoretical framework and a methodology based on the process tracing. We identified four variables (states' interests, the political context, leadership, and the International Geophysical Year [IGY]) that we studied through three historical periods and whose evolution has contributed to elaborating the Antarctic regime. The steps leading to the development of a regime, identified in Frischmann’s dynamic institutionalism theory, apply to the three periods that we have identified. The first historical period corresponds to identifying an interdependency problem. States first tried to satisfy their particular interests pertaining to the Antarctic continent through individual strategies. The unclear status of the Antarctic continent characterized by conflicting claims, the will of the superpowers to potentially make territorial claims, and the leadership of the United States, however, facilitate the states to move to more cooperative strategies. The second historical period corresponds to negotiating the agreement. The leadership of a group of scientists and the United States in addition to the political context of the Cold War facilitated the cohesion of states interested in Antarctic affairs and their investment in a soft multilateral cooperation, the IGY. The third period corresponds to implementing the agreement, that is IGY. During this event, the parties have respected a tacit agreement, a gentlemen’s agreement, which suspended territorial considerations in Antarctica. The cooperation during the IGY proved to be a success. States were satisfied with their gains from the scientific cooperation in a peaceful environment. The IGY has allowed states to experiment multilateral cooperation and to observe the behavior of other participants within the institution. Due to the satisfaction of the states vis-à-vis the cooperation, the development of the 1959 Treaty was facilitated. Through our study, we identified key elements that led to the creation of the Antarctic regime and could serve as an inspiration for the development of future regime. The continuous of leadership throughout the process helped to promote the benefits of cooperation and to strengthen relations between the states involved in Antarctic affairs. The accomplishment of a soft agreement, during the IGY, centered around the parties common interests, and of a gentlemen’s agreement, which put aside divisive issues were also central points in the success and the extension of the coopération after the IGY. This gradual approach from soft law to hard law is undoubtedly the most important element that facilitated the cohesion of parties and the creation of the Antarctic Treaty.

Afin d’étudier les variations climatiques enregistrées par les carottes de glace, il est nécessaire d’avoir des datations précises à la fois pour les phases gaz et glace. Le but de ce travail de thèse a été d’améliorer les chronologies des carottes de glace, couvrant les derniers 800 000 ans, au travers de nouvelles mesures de la composition isotopique de l’air (δ15N, δ18Oatm et δO2/N2) piégé dans la glace d’EPICA Dôme C (EDC) et de l’utilisation de l’outil de datation "Datice". Le premier résultat important de cette thèse a été la production de la chronologie cohérente pour les carottes de glace ("Antarctic Ice Core Chronology", AICC2012) pour EDC, Vostok, EPICA Droning Maud Land (EDML), TALos Dôme ICE core (TALDICE) et NorthGRIP. Sur cette nouvelle chronologie la théorie du see-saw bipolaire reste valable. AICC2012 donne un âge pour la Terminaison II en accord avec les autres archives climatiques. De plus, les durées des périodes interglaciaires restent inchangées par rapport à la chronologie EDC3. Lors de la construction d’AICC2012 nous avons mis en évidence plusieurs points nécessitant des améliorations. Nous avons donc procédé à l’amélioration de Datice dans le but d’intégrer correctement les contraintes issues du comptage des couches annuelles et leurs erreurs. Ces améliorations conduisent à des chronologies cohérentes tout en respectant les hypothèses sous-jacentes à Datice. Nous proposons aussi une nouvelle formulation de l’erreur associée à la fonction d’amincissement à partir de l’analyse des propriétés mécaniques de la glace dans le cas d’EDC. Pour finir, les nouvelles mesures du δO2/N2 et du δ18Oatm effectuées sur de la glace bien conservée d’EDC nous ont permis de définir de nouvelles contraintes d’âge. La comparaison de ces traceurs mesurés à Vostok, EDC et Dôme F sur le MIS 5 a permis de mettre en évidence une possible influence de paramètres climatiques locaux sur le δO2/N2. L’analyse du retard entre le δ18Oatm et la précession sur les derniers 800 ka montre des variations de ce dernier. Nous suggérons que ce retard est augmenté par l’occurence d’évènements de Heinrich à certaines périodes. Les résultats de cette thèse sont à prendre en compte pour le prochain exercice de datation cohérente pour les carottes de glace. / In order to study the climate variations recorded by ice cores, it is necessary to have precise chronologies for the ice and gas phases. The aim of this work has been to improve ice cores chronologies, covering the last 800 000 years, through new measurements of the isotopic composition of the air δ15N, δ18Oatm et δO2/N2) trapped in EPICA Dome C (EDC) ice core and the use of the Datice dating tool.The first important result of this PhD has been the production of the Antarctic Ice Core Chronology (AICC2012), common for EDC, Vostok, EPICA Droning Maud Land (EDML), TALos Dome ICE core (TALDICE) and NorthGRIP ice cores. The bipolar see-saw theory is still valid on the new chronology. The AICC2012 chronology gives an age for Termination II in good agreement with other climate archives. Moreover, the duration of interglacial periods is unchanged compared to EDC3. While building the AICC2012 chronology, we have pointed out several limitations. Since then, we have improved Datice in order to correctly integrate constraints deduced from layer counting and their associated uncertainties. These improvements permit to build coherent chronologies respecting the underlying hypotheses of Datice. Moreover, we propose a new parameterization of the uncertainty associated with the background thinning function based on ice mechanical properties of EDC ice core. Finally, we were able to deduce new age constraints thanks to the new measurements of δO2/N2 and δ18Oatm performed on well-conserved ice from EDC. A multi-proxy comparison of Vostok, EDC and Dome F ice cores over MIS 5 has highlighted a possible influence of local climatic parameters on δO2/N2. The analysis of the delay between δ18Oatm and precession shows some variability over the last 800 ka. We propose that the delay between δ18Oatm and precession is increased during periods associated with Heinrich events. The results obtained during this PhD should be used for the next ice core coherent chronology.

Diatoms (Bacillariophyta) are one of the most diverse algal groups in the Antarctic Region and play a dominant role in almost all freshwater and terrestrial ecosystems. Despite this overall occurrence, little is known about the diversity, ecology and biogeography of this group in the Maritime Antarctic Region. The main objective of this thesis is therefore to define the taxonomical, ecological and biogeographical characterisation of aquatic, semi- aquatic and moss-inhabiting diatom communities from two islands in the Maritime Antarctic Region: James Ross Island and Livingston Island, located on opposite sides of the Antarctic Peninsula. In this study, a total of 250 samples from three different habitat types (lakes, streams & seepage areas and mosses) from Byers Peninsula (Livingston Island) and Ulu Peninsula (James Ross Island) have been analysed. Using light and scanning electron microscopy, a rather diverse diatom flora composed of 178 taxa, belonging to 43 genera has been identified. Although even until recently, it was generally accepted that the Antarctic diatom flora was mostly composed of cosmopolitan taxa, several new species could be described as a new for science during this PhD study (a reflection of this work is presented in chapters 2 & 3 and in Appendices). Habitat type and...

A necessidade de proteger a pele contra os raios ultravioleta (UV) é imprescindível, tendo em vista os efeitos deletérios gerados pelos mesmos. Compostos convencionais com atividade fotoprotetora sofrem interações, instabilidade e em sua maioria protegem contra os raios UVB. Poucos compostos apresentam proteção contra os raios UVA. No ambiente marinho, como nas algas marinhas, adversidades do ambiente relacionadas, principalmente, a exposição solar, aumentam as defesas naturais contra os raios UV por meio da produção de metabólitos secundários que podem absorver/refletir os raios solares, ou agir como antioxidantes. Tais moléculas podem ser produzidas pelas próprias algas ou pelos fungos endofíticos associados a elas. Assim, o presente estudo tem como objetivo investigar o potencial fotoprotetor de extratos, frações e substâncias isoladas dos fungos endofíticos Xylaria sp e Annulohypoxylon stygium, associados à alga vermelha Bostrychia radicans. Bem como de quatro espécies de algas da Antártica, Palmaria decipiens, Monostroma hariotii, Desmarestia anceps e a Gigartina skottsbergii. As algas da Antártica foram disponibilizadas pelo grupo do Prof. Dr. Pio Colepicolo Neto do IQ-USP e o cultivo dos fungos, a extração e o isolamento foram desenvolvidos em parceria com o Laboratório de Química Orgânica do Ambiente Marinho - NPPNS da FCFRP-USP. Os extratos e frações obtidos foram submetidos à análise dos espectros de absorção no UV e à fotodegradação. A seguir, os extratos e frações mais promissoras foram submetidos à avaliação da fototoxicidade em cultura de fibroblastos 3T3 para a determinação da viabilidade celular na presença e ausência da radiação, de acordo com o protocolo OECD TG 432. O fungo A. stygium apresentou frações com absorção no UVB, duas subfrações se mostraram não cito/fototóxicas e são provenientes de frações fotoestáveis. Destas subfrações, duas substâncias, ambas inéditas, foram isoladas e elucidadas por RMN H1, 1D, 2D, IV, ESI, e estas foram consideradas potenciais ativos para fotoproteção no UVB. O fungo Xylaria sp apresentou frações com absorção na região do UV, porém apenas uma, com absorção no UVB se mostrou fotoestável. Esta mesma fração foi considerada cito e fototóxica. Não foi possível identificar as duas substâncias isoladas pela baixa massa. Entretanto, um metabólito já isolado dessa linhagem anteriormente, o ácido gentísico, foi considerado não fototóxico, devendo ser melhor investigado quanto ao seu potencial como filtro biológico. Quanto às macroalgas antárticas, três espécies apresentaram absorção no UV. Apesar de a maioria dos extratos terem sido considerados fotoinstáveis, o extrato da alga D. anceps, de maior rendimento, apresentou frações com ampla absorção no UVA/VIS, no entanto elevada citotoxicidade. Desta fração foi isolada e identificada a fucoxantina (RMN H1 1D e 2D, ESI), um carotenoide marinho que apresentou potencial fototóxico no modelo monocamadas, mas não foi considerada citotóxica. Sendo assim, este pode ser considerado um promissor candidato a ativo cosmético, pelas suas propriedades antioxidantes e de filtro biológico, pois devido a sua alta massa molecular, 658.90 g/mol, pode-se inferir baixa permeação nas camadas viáveis da pele e ausência de fototoxicidade in vivo. Nesse sentido, novos estudos em modelo de pele 3D deverão ser realizados a fim de se comprovar a segurança de uso tópico da fucoxantina. As espécies também devem ser investigadas para outras atividades biológicas uma vez que este material pertence a uma região pouco estudada e estas podem apresentar potencial para os mais diversos empregos farmacológicos ou cosméticos. / The need to protect the skin against ultraviolet (UV) radiation is essential, due to the deleterious effects caused by them. Conventional UV-filters undergo chemical interactions, instability and mostly protect against UVB rays. Few compounds have protection against UVA rays. In the marine environment, especially in marine algae, adversities, mainly related to sun exposure, increases the natural defenses against UV radiation through the production of secondary metabolites that can absorb/reflect the UV radiation, or even act as antioxidants. Such molecules may be produced by algae themselves or by the endophytic fungi associated with them. The present study aims to investigate the potential of new sunscreen extracts, fractions and isolated compounds from endophytic fungi Xylaria sp and Annulohypoxylon stygium, associated with red algae Bostrychia radicans, and four species of algae from Antarctica: Palmaria decipiens, Monostroma hariotii, Desmarestia anceps and Gigartina skottsbergii. The algae material from Antarctica were given by the group of Prof. Dr. Pio Colepicolo Neto, IQ-USP, and the fungi cultivation, extractions and the compounds isolation were obtained in partnership with the Laboratory of Organic Chemistry of the Marine Environment - NPPNS of FCFRP-USP. The extracts and fractions obtained were submitted to analysis of the absorption spectra in the UV and to photodegradation. After that, the most promising extracts and fractions were submitted to the assessment of phototoxicity in 3T3 fibroblasts in culture for determination of cell viability in the presence and absence of radiation, in accordance with the OECD TG 432 protocol. The fungus A. stygium showed fractions with UVB absorption, from there were isolated two novel compounds and had the structure elucidated (RMN H1 1D/2D; IV; ESI). These compounds were considered potential ingredients for photoprotection on the UVB range. The fungus Xylaria sp. showed fractions with absorption on the UV, but only one of them, with UVB absorption, was considered photostable. The same fraction was also considered cyto/ phototoxic. It was not possible identify two of the compounds isolated due its low weight. Therefore, the gentisic acid, a metabolite already isolated from this fungus, was not considered phototoxic, what suggests that it should be better investigated as a potential biological UV filter. Regarding the seaweeds, three species have shown absorption in UV region. Most of the extracts were considered photounstable, but the D. anceps extract, of highest yield, showed fractions with large UVA/VIS absorption, but higher cytotoxic potential. Fucoxanthin, a marine carotenoid, was isolated from this fraction and identified by NMR H1 1D/2D, ESI. This compound showed phototoxic potential in a monolayer model, but it was not considered cytotoxic. Therefore, fucoxanthin is a promising candidate to a cosmetic ingredient, once it has antioxidant and biological UV filter properties and its high molecular weight, 658.90 g/mol, suggests low skin permeation into viable epidermis and absence of in vivo phototoxicity. Thus, more studies using 3D skin model should be performed in order to prove the safety of the fucoxanthin topical use. The species should be also investigated for other biological activities once this material belongs to a poorly studied region and can show potential for many of the pharmacological/cosmetics activities.

A complexa interação que ocorre entre os processos oceânicos e atmosféricos no Oceano Austral afeta a circulação oceânica global em diferentes camadas. O Mar de Weddell e o Mar de Ross possuem reconhecida importância na formação da Água de Fundo Antártica (AABW). O objetivo principal deste trabalho é caracterizar as massas de água dos Mares de Weddell e Ross, através dos dados mais recentes de reanálise oceânica SODA (Simple Ocean Data Assimilation). Através da técnica de separação de massas de água Análise Multiparamétrica Ótima (AMO) foi possível a identificação de 3 principais massas de água no Mar de Ross: Água Profunda Circumpolar Superior (UCDW), Água Profunda Circumpolar Inferior (LCDW) e Água de Plataforma de Baixa Salinidade (LSSW). A UCDW foi a que apresentou a maior variabilidade, não atingindo a Plataforma de gelo do MR durante os anos de 1950-1974. No Mar de Weddell foi possível a identificação das seguintes massas de água: Água Profunda Cálida (WDW), Água Profunda do Mar de Weddell (WSDW) e Água de Fundo do Mar de Weddell (WSBW). A WDW atingiu valores >70% à 800m. A WSDW possui em seu núcleo valores > 90% entre 2000 e 3500m. A WSBW, apresenta ~100% em profundidades > 4000m. / The complex interaction that occurs between the oceanic and atmospheric processes in the Southern Ocean affects global ocean circulation in different layers. The Weddell and Ross Seas have recognized importance in the formation of Antarctic Bottom Water (AABW). This work aims to characterize the water masses of the Weddell and Ross Seas, using the latest ocean data reanalysis SODA (Simple Ocean Data Assimilation). Through the water masses separation technique, Optimum Multiparameter Analysis (OMP), it was possible to identify three main water masses in Ross Sea: Upper Circumpolar Deep Water (UCDW), Lower Circumpolar Deep Water (LCDW) and Low Salinity Shelf Water (LSSW). UCDW showed the greatest variability, not reaching the Ross Sea Ice Shelf during the years 1950-1974. It was possible to identify the following water masses in Weddell Sea: Warm Deep Water (WDW), Weddell Sea Deep Water (WSDW) and Weddell Sea Bottom Water (WSBW). WDW reached values up to 70% in 800m. WSDW has in its core values > 90% between 2000 and 3500m. WSBW presents a contribution up to 100% at depths > 4000m.

O clima na Antártica tem um papel fundamental no balanço de energia global. Estudos sugerem que a atividade convectiva tropical e a circulação estratosférica exercem um papel importante sobre a circulação atmosférica nos extratrópicos. A temperatura do ar é uma variável sensível às mudanças na circulação, no entanto, ainda não foi investigada a importância da escala intra-sazonal na sua variabilidade sobre a Antártica. Neste trabalho estudou-se a variabilidade intra-sazonal da temperatura do ar a superfície na região da Península Antártica enfocando as interações trópicos-extratrópicos e troposfera-estratosfera na modulação de eventos extremos de temperatura naquela região. Foram utilizados dados diários de estações localizadas nos setores leste e oeste da Península Antártica no período de 1986-2002. A análise espectral dos dados ressaltou a importância da escala intra-sazonal na variabilidade da temperatura na Península Antártica, principalmente no período de inverno, primavera e verão. Baseado nestes resultados, os dados foram filtrados na escala intra-sazonal (banda de 20-100 dias) e posteriormente, obteve-se os extremos intra-sazonais frios e quentes para as três estações do ano, através dos quartis da distribuição dos dados. Os eventos extremos intra-sazonais de temperatura (EIT) foram mais intensos no inverno e mais fracos no verão. As características da circulação atmosférica intra-sazonal associada aos EIT foram obtidas através de composições defasadas das anomalias intra-sazonais da altura geopotencial em 200 hPa, vento zonal em 200 hPa e vento meridional em 850 hPa. Nas três estações do ano, observou-se nos eventos extremos intra-sazonais frios (EIF) a persistência de anomalias ciclônicas em altos níveis, a diminuição da intensidade do jato polar e uma advecção de ar frio em baixos níveis sobre a região de estudo. Uma situação oposta foi verificada nos eventos extremos intra-sazonais quentes (EIQ). De forma geral, observou-se um trem de ondas entre latitudes médias e altas no Hemisfério Sul (HS) durante os EIT, particularmente no inverno e primavera. Esta configuração mostrou-se semelhante a tele-conexão conhecida como Pacífico-Sul Americano (PSA). O papel do modo anular do HS sobre os EIT foi analisado através do cálculo de Funções Ortogonais Empíricas das anomalias intra-sazonais da altura geopotencial em 700 hPa ao sul de 20ºS. Sua estrutura foi mais intensa (mais fraca) nos EIF (EIQ) de inverno sobre a região de estudo. A interação troposfera-estratosfera no controle dos EIT foi investigada através do Fluxo Eliassen-Palm. Nas composições das anomalias intra-sazonais deste fluxo (EPIS), observou-se durante os EIF (EIQ) de inverno, um aumento da atividade de onda da baixa estratosfera (alta troposfera) para a alta troposfera (baixa estratosfera) sobre a região de estudo, associado à diminuição (aumento) da intensidade do jato polar. Na primavera, a atividade de onda foi mais intensa e verificou-se uma mudança na direção do fluxo EPIS quando comparado com os EIT de inverno. O fluxo EPIS e as anomalias intra-sazonais do vento zonal foram mais fracos no verão. As anomalias intra-sazonais da circulação atmosférica e da atividade de onda na troposfera e estratosfera foram observadas por cerca de 10 dias antes da observação dos EIT de inverno. Portanto, a atividade intra-sazonal nos extratrópicos e as interações troposfera-estratosfera são fatores relevantes para um melhor entendimento da variabilidade da temperatura sobre a Península Antártica. / The Antarctic climate plays a significant role for the global energy budget. Previous studies suggest that interactions tropics-extratropics and the dynamics of the stratosphere are important factors to understand climate variations in the extratropics. The air temperature near surface responds to changes in circulation in low and upper levels. However, no previous studies have objectively investigated the importance of intraseasonal variations in modulating temperature around the Antarctica Peninsula. The present study examines intraseasonal extreme anomalies of near surface air temperature in the Antarctica Peninsula, and investigates interactions tropics-extratropics and troposphere-stratosphere. Daily temperature data from stations located east and west of the Antarctica Peninsula during 1986-2002 are investigated. Spectral analyses indicate that intraseasonal anomalies in temperature records are statistically significant during summer, winter and spring in all stations. Based on these results, temperatures are band-filtered on intraseasonal timescales (20-100 days) and extreme anomalies are investigated in each season (spring, summer and winter) based on the quartiles of the distributions. Intraseasonal extreme temperature (IET) anomalies are more intense during winter than during summer. Variations in the atmospheric circulation during IET are investigated by performing composites of intraseasonal anomalies of the geopotential height in 200hPa, zonal wind in 200hPa and meridional wind in 850hPa. During the three seasons, cold IET are associated with persistent upper level cyclonic anomalies, easterly anomalies of the polar jet and cold advection in low levels over the Peninsula. Opposite features are observed during warm IET. An extratropical wave-train is observed during all IET with stronger intensity during winter and spring. This feature resembles the Pacific South American (PSA) teleconnection pattern. The Southern Hemisphere Annular mode during the IET, identified as the first Empirical Orthogonal Function (EOF) of the intraseasonal 700hPa geopotential height anomalies poleward of 20oS, is more intense (weak) during cold (warm) IET events during winter. The stratosphere-troposphere interaction during IET events was examined with composites of the Eliassen-Palm Flux intraseasonal anomalies (EPIS). During spring, the wave activity is more intense and the EPIS direction is opposite to winter. During summer, EPIS are weak. Intraseasonal anomalies in the circulation and the wave activity in the troposphere and stratosphere lead the IET during winter in about 10 days. Therefore, the intraseasonal activity in the extratropics and the interactions stratosphere-troposphere are important factors for a complete understanding of the temperature variability over the Antarctica Peninsula.

Em fevereiro de 2012 um incêndio atingiu a Estação Antártica Comandante Ferraz (EACF), consumindo cerca de 70% das instalações, liberando diversos compostos para o meio ambiente. Desde então, processos de remoção de resíduos vêm sendo realizados. Com base no cenário de efeitos ambientais em um ambiente antártico, amostras de solo e sedimento foram coletadas em diferentes períodos pós-acidente a fim de se avaliar os efeitos do incêndio. As amostras foram tratadas através de digestão ácida e as concentrações parciais de metais e As foram quantificadas através de ICP-OES. O Fator de Enriquecimento foi utilizado para avaliação dos impactos causados no solo, enquanto que comparação com os valores estabelecidos pela legislação canadense (TEL e PEL) foi utilizada na avaliação do grau de contaminação do sedimento. Os resultados indicaram a introdução de Pb, Cu e Zn antropogênico em parte das amostras de solo coletadas ao redor da antiga estação antártica, cujos Fatores de Enriquecimento chegaram a, respectivamente, 208,9; 189,7 e 111,6; sendo estes presentes sob a forma de fragmentos metálicos. Também indicaram que os processos de remoção de resíduos podem ter sido tanto responsáveis pela redução nos teores de metais, como por ter reintroduzido estes elementos em outros pontos mobilizando-os durante a movimentação de resíduos. Além disso, não foram encontradas evidências de alterações significativas nos teores de Hg em solo e metais e As em sedimento marinho. / In February 2012, a fire at the Comandante Ferraz Antarctic Station (EACF) destroyed approximately 70% of the Brazilian research station. This event released many substances and residues to the region and, since then, operations for the removal of the fire wastes have been executed. Based on the scenario of environmental effects on an Antarctic environment, soil and sediment samples were collected in several different moments after the accident to study the impacts of the fire. The samples were treated through acid digestion and the partial levels of metals and As were quantified through ICP-OES. Enrichment factor was used to evaluate the impacts caused in soils, and comparisons with Canadian environmental quality guidelines (TEL and PEL) were used to assess the intensity of the sediment contamination. The results indicated the introduction of anthropogenic Cu, Pb and Zn in some of the collected soil samples around the former Antarctic station, with enrichment factors of 189.7, 208.9 and 111.6, respectively, elements those present in metallic fragments. Moreover, the analysis of the generated data showed that the procedures for wastes removal could have been responsible for the decrease in the elements\' content as well as the reintroduction of those elements due to the mobilization of the wastes in some of the sampled sites. Furthermore, there\'s no evidences of significate changes on Hg levels in soil or metal and As levels in marine sediment.

A desintegração da plataforma de gelo da enseada Larsen A, em 1995, possibilitou uma oportunidade para estudar a comunidade bêntica da região. Foram analisadas a densidade da macrofauna e a densidade e biomassa da meiofauna. Duas estações na região de mar aberto, no Mar de Weddell, também foram coletadas, para comparações entre diferentes ambientes. Parâmetros ambientais também foram analisados, e serviram para tentar explicar a variação da fauna bêntica. Na região do Mar de Weddell as porcentagens de matéria orgânica foram maiores que na enseada Larsen A, provavelmente um reflexo da maior produtividade primária da área, enquanto as porcentagens de carbonato foram mais altas na enseada do que em mar aberto. A granulometria variou entre silte arenoso a areia síltica, sendo as estações no Mar de Weddell tiveram maiores porcentagens de areia. Em relação à fauna, Nematoda foi o táxon mais abundante, seguido por Copepoda e Nauplii dentro da meiofauna, enquanto Bivalvia e Polychaeta foram os mais abundantes dentro da macrofauna. As maiores densidades de meio- e macrofauna foram encontradas nas estações de mar aberto, e apresentaram correlação com as concentrações de pigmentos. A biomassa total dos nemátodes se correlacionou à biomassa individual do grupo, enquanto a biomassa dos copépodes se correlacionou com a densidade do grupo. Através dos resultados obtidos no presente trabalho foi possível observar que as comunidades bênticas das duas regiões estudadas diferem entre si, em termos de densidade e número de grandes grupos encontrados. E que a disponibilidade de alimento é o principal fator estruturados da fauna na região. / The collapse of the Larsen A ice shelf, in 1995, allowed an opportunity to study the benthic community in the region. The density of macrofauna and the density and biomass of meiofauna were analyzed. Two open water stations in the Weddell Sea were also collected for comparisons between different environments. Environmental parameters were analyzed to look for possible relations with benthic fauna distribution, abundance and biomass. In the Weddell Sea region the percentage of organic matter were higher than in the Larsen A, which was probably a reflection of the higher primary productivity of the area, while the carbonate percentages were higher in the bay than in open water. Particle size ranged from sandy silt to siltic sand, with Weddell Sea stations presenting higher sand content. Nematoda was the most abundant meiofauna taxon, followed by copepods and Nauplii, while Bivalvia and Polychaeta were the most abundant macrofauna. The highest densities of meio- and macrofauna were found in the open sea stations, and were correlated with pigment concentrations. The total nematode biomass was correlated with nematode individual biomass of the group, while copepod biomass correlated with its density. We observed that the benthic communities differed between studied areas in terms of density and taxon richness. Food availability appears to be the main factor structuring fauna in the region.