Rozprawy doktorskie na temat „Antarctica”

One of the biggest problems of our time is the global warming. A direct result of this phenomena is the melting of ice of the glaciers on the north and the south pole. As this continues, the melted ice will contribute to an increase of the sea level, and may cause enormous natural disasters. To be able to prevent this, it’s important to study its affects. This reports contains a concept study of a Unmanned Aerial Vehicle, a UAV, set on the coast of Antarctica by the Australian owned base Davis Station to document the changes and retracting of the glacier borderline. The purpose of the aircraft is to scout a pre-determined path whilst documenting the glaciers with photography from above.

Connections between South Africa and Antarctica can be traced as far back as the 1700s when European expeditions in search of the southern continent used Cape Town (and later Simonstown) as a base of operation. This link expanded considerably after formal British acquisition of the Cape of Good Hope in 1815, yet it was not until 1926 that an actual South African policy towards the Antarctic began to materialize. Once this policy was established it continued to be characterized by procrastination as well as resistance both from within and without South Africa. The history of South Africa's Antarctic policy can be divided into five periods: first, the commencement of the policy (focusing primarily on economic interests), 1926-1939; second, the pursuit of interests through the policy (focusing on political interests), 1944- 1958; third, the entrenchment of South Africa's interests in the Antarctic (by securing South Africa's position within the Antarctic Treaty System), 1958-1960; fourth, the expansion of and foreign assault on the policy (under the auspices of the Antarctic Treaty System), 1960-1988; and fifth, the defence of and future prospects for the policy (from United Nation's calls for South Africa's exclusion from the Antarctic Treaty System), since 1982. While resistance from inside and outside the government during the first two periods resulted from inadequacies in the South African Antarctic policy itself, resistance in the final two periods has centred upon non-Antarctic issues. As South Africa has faced ever-increasing exclusion from international governmental organizations over opposition to Its apartheid policies, organizations such as the Antarctic Treaty Organization have inevitably been drawn into the debate. As a result, the Consultative Parties of the Antarctic Treaty (of which South Africa is one of the original twelve) have been forced to deal with the following question: to what extent will political issues outside the scope of the management policies of the Antarctic Treaty Organization be allowed to affect the functioning of the Antarctic Treaty System? While the Consultative Parties continue to ponder this and the fact that South Africa's Consultative Status has become the most divisive factor within the Antarctic Treaty System, no final solutions to these issues appear likely before 1991.

In light of growing international awareness and interests in the ‘frozen continent’ of Antarctica, the topic of Values in Antarctica has recently gained more research interest. Due to the complexity of the concept of value, values in Antarctica have been approached from many different perspectives, including Antarctic wilderness and aesthetic values, values manifested in Antarctic law or value based behavioural changes through the Antarctic experience. The present thesis addresses values as human connections to Antarctica with a focus on Antarctic policy-making. The investigation contained three analytical stages that built on each other. The first stage has been an interdisciplinary literature review examining what values are and how values can be studied, but also considered values in the context of environment, human behaviour and policy. Value and value-related concepts were selected in view of a potential application to the Antarctic. The second analytical stage involved a general framework analysis of the Antarctic Treaty System to identify key elements and structures in the system suitable for a study of Antarctic values, and to develop the research questions. The third stage of analysis included empirical investigations of two Antarctic case studies. Key elements that influence the Antarctic Treaty System in a way that is relevant for a study of Antarctic values include external factors and events, action situations and actors participating in these action situations. Antarctic Treaty Meeting of Experts appeared as an action situation particularly suitable for a study of Antarctic values. The last two Antarctic Treaty Meeting of Experts on ship-borne tourism and climate change have been chosen as case studies, presenting two topical issues in Antarctic policy. Using discourse analysis based on documents submitted to the meetings and the meetings’ reports, values that are driving the discourses were to be identified through structures and patterns in the discourses. Further, based on the discourse analysis following three research questions were to be answered: What role is ascribed to Antarctica concerning contemporary issues? Where and why do conflicts arise in the ATS policy-making process that are based on conflicting values? What changes in the underlying belief-systems are driving policy-making processes and what has caused the change? Based on the literature, values are defined as internalised codes that affect behaviour and include judgements on what is good and desirable. Through the framework analysis it was identified that Antarctic policy involves a multi-layered system of different value systems, which was considered in the two case studies. For both case studies, values in the discourses were mostly identified based on Schwartz’s basic human value theory. The most prominent human value that drives both the ship-born tourism and the climate change discourse is security. Both discourses are further motivated by the conservation of the Antarctic environment and its associated ecosystems. Other values, such as power and conformity with rules were also clearly expressed in the discourses. With regard to the research questions, both case studies discussed Antarctica from two different perspectives, as a hazardous place for human activities and as a place vulnerable to any kind of changes. Conflicts in the ship-borne tourism discourse were more obvious, while the climate change discourse within the expert meeting proceeded in consensus. Value-based changes that are evident in changes in belief-systems underlying Antarctic policy-making could not be identified. This thesis argues, based on careful consideration of documents, that values play a crucial role in Antarctic policy-making at a number of different scales: individuals, political actors, and governmental levels. Values were found to be at the core of most, if not all, conflicts within the Antarctic system. Finally, this thesis provides the first understanding of the values held by the various stakeholders involved in governing and use of the Antarctic, which is crucial for further decision-making and research.

The Antarctic silverfish (Pleuragramma antarctica) is a keystone species in the continental shelf waters around the Antarctic, performing an essential role of connecting higher and lower trophic levels in the Southern Ocean ecosystem. Its early life history is dependent on the platelet ice layer found below sea ice, thus intimately intertwining its fate with that of sea ice extent. Antarctic silverfish belong to the family Nototheniidae, part of the Notothenioidei suborder whose species radiation in the Southern Ocean 24 million years ago is one of the most expansive among teleost fish. Most notothenioids inhabit a benthic niche as adults, though many experience a pelagic egg and larval phase. Antarctic silverfish are unique among notothenioids in that they are pelagic throughout their life history. Larvae develop in the platelet ice layer near the surface beneath sea ice, descending into deeper waters as they grow in size as juveniles, finally reaching their maximum depth range as adults at 400 – 700 m below the surface. While they lack a swim bladder, Antarctic silverfish manage to remain in the water column as adults by a type of paedomorphy in which they retain lipids from larval and juvenile life stages, allowing them to achieve neutral buoyancy. Despite their presence in the water column as adults, they practice a similar energy-efficient life strategy to their benthic counterparts. Their feeding strategy involves hanging in the water column and passively consuming prey. Remaining in the water column throughout their life history combined with their passive life strategy renders Antarctic silverfish especially susceptible to transport via local and circumpolar current systems. Thus, local and circumpolar current systems form the hydrographic framework in which hypotheses regarding Antarctic silverfish population connectivity must be tested. How populations of fish are defined, and the extent to which separate populations exchange individuals forms the basis of marine fish population biology. The extent to which Antarctic silverfish, which have a circumpolar distribution, represent one fully connected, panmictic population around the Antarctic continent, remains an open question. It is reasonable to presume that, given their pelagic larval phase, many species of notothenioids with a circumpolar distribution represent large, homogeneous populations. This presumption remains the null hypothesis to test when investigating population structure in notothenioids, and it is especially salient when considering the fully pelagic Antarctic silverfish. The first investigation into Antarctic silverfish population structure employed mitochondrial DNA markers on a circumpolar scale and did not find evidence to reject the null hypothesis of panmixia throughout the Southern Ocean. Intriguingly, while comparisons between regions failed to indicate differentiation, comparisons within regions between years hinted at inter-annual variation in patterns of connectivity. Genetic differentiation within the same geographic area that is lost and gained between sampling years due to variations in recruitment, mortality and hydrography is known as chaotic genetic patchiness. The extent to which chaotic genetic patchiness is relevant to understanding Antarctic silverfish population structure was further studied in a more recent investigation, restricting its geographic focus to the Antarctic Peninsula, and employing a set of highly polymorphic EST-linked microsatellite markers to understand population connectivity around the Antarctic Peninsula. Based on both its more focused regional scale and sampling scheme, as well as the use of genetic markers more adept at capturing population differentiation, this study was able to detect genetic structuring on the scale of the Antarctic Peninsula. Building upon these initial studies, this thesis aimed to characterize the circumpolar population structure of Antarctic silverfish, integrating aspects of life history and hydrography in order to describe mechanisms of connectivity between populations. The first aim was to understand the hydrography underlying life history connectivity on the scale of the Ross Sea region in order to better understand what may be occurring on the circumpolar level. Silverfish larvae were collected from areas in the Ross Sea coincident with hydrographic features hypothesized to influence their connectivity. While a microsatellite-based analysis was precluded due to the poor state of preservation of the larvae, it was possible to confirm species identification using mitochondrial sequence analysis. The genetic confirmation of species was especially important given that this study proposed a new spawning ground for silverfish in the Ross Sea based on size at collection and established growth rates from the time of hatching. Importantly, this study provided renewed support for the life history hypothesis in silverfish, emphasizing the impact of trough circulation in transporting early life stage fish from the ice shelf edge to the continental slope, where retention back towards the coast or entrainment in shelf-long currents modulates connectivity between neighboring populations of silverfish. The Ross Sea investigation was then expanded on a circumpolar scale, now carried out using a suite of highly polymorphic EST-linked microsatellite markers developed in a closely related notothenioid species and shown to successfully amplify in silverfish in a previous study. This analysis was carried out on fish collected over 25 years from six different regions: the western Ross Sea, the eastern Weddell Sea, Larsen Bay, the northern Antarctic Peninsula, the South Orkney Islands, and the western Antarctic Peninsula. The data analyzed included samples from the two previous investigations of silverfish population structure described earlier, the first using mitochondrial markers on a circumpolar scale that had not found evidence of population structuring, and the second using the same suite of microsatellite markers employed in this thesis on a regional scale around the Antarctic Peninsula. The integration of these previous datasets into the present analysis allowed for an increase in the resolving power of the previous mitochondrial marker-based study, as well as for the integration of the Antarctic Peninsular work into the greater circumpolar context. The circumpolar investigation of Antarctic silverfish population structure confirmed that the population structure of silverfish on a circumpolar scale is characterized by high levels of gene flow, and suggested that the Antarctic Slope Front and Current System (AFS) plays an integral role in connecting populations in the Southern Ocean. The importance of the AFS was evident in that reductions in gene flow were only observed in the South Orkney Islands and west Antarctic Peninsula, which were the only two areas in the study where the AFS has not been shown to arrive. This result also expanded to a circumpolar scale the earlier Ross Sea study, which had emphasized the importance of the AFS in connecting Ross Sea populations between local trough systems. It remained however, that small scale population differentiation which had been observed in the Ross Sea based on larval distributions, as well as in the eastern Weddell Sea based on the distribution of older and younger cohorts between sampling areas, was unable to be resolved using genetic techniques. Thus, the final aim of the main project of this thesis was carried out in order to resolve population structure on the regional scale, this time in the Weddell Sea, employing otolith chemistry. Analysis of trace element deposition in otolith nuclei, reflective of oceanographic conditions to which fish were exposed in early life, has been shown to delineate population structure in the Southern Ocean, in both silverfish and related notothenioids. Of the stations for which samples were available in the Weddell Sea, five stations were selected based on their locations with respect to hydrographic features hypothesized to influence population structuring in the region, in Atka Bay, Halley Bay, off of Coats Land, and west and east of the Filchner Trough. Previous studies, as well as data on biomass and abundance from the sampling expedition during which the silverfish were collected, emphasized the importance of the Filchner Trough in supporting a local population of silverfish in the eastern Weddell Sea continental shelf area. Furthermore, hydrographic data collected in the Weddell Sea emphasized the importance of warm water mass intrusion onto the continental shelf carried from the east into the Weddell Sea region by the AFS. These warm water intrusions from the AFS not only have the potential to carry fish from other regions into the Weddell Sea area, but regulate circulation patterns and the strength and directionality of coastal currents in the region, modulating local connectivity. The results of the otolith nucleus chemistry analysis revealed significant population structuring along the eastern Weddell Sea, in contrast to the structure revealed using genetics. The population structure revealed by the otolith chemistry analysis supported the importance of warm water intrusions from the AFS in transporting fish between areas, while highlighting the role of the Filchner Trough circulation in supporting a coherent population in the southeast Weddell Sea. These results emphasize the importance of the integration of multidisciplinary techniques in the context of local hydrography in addressing questions of population structure and life history connectivity in Antarctic silverfish in the Southern Ocean, and for that matter, any pelagic species inhabiting a continental shelf ecosystem.
L’antarctic silverfish (Pleuragramma antarctica) è una specie chiave nelle acque della piattaforma continentale antartica, dove svolge un ruolo essenziale nel collegare i diversi livelli trofici. La sua life history dipende, nella prima fase, dal cosiddetto “ghiaccio a placchette” (platelet ice), che si forma all’interfaccia tra l’acqua marina e lo strato di ghiaccio superficiale, legando strettamente il destino di questa specie all’estensione del ghiaccio antartico. L’antarctic silverfish appartiene alla famiglia Nototheniidae, che fa parte del sottordine dei Nototenioidei, la cui radiazione, avvenuta nell’oceano Antartico a partire da 24 milioni di anni fa, rappresenta una delle più spettacolari radiazioni adattative nei pesci teleostei. I nototenioidei comprendono, nella maggior parte dei casi, specie demersali in fase adulta, ma caratterizzate da uova e larve pelagiche; l’antarctic silverfish è unico sotto questo punto di vista perché è pelagico durante tutto il ciclo vitale. Le larve si sviluppano nello strato di platelet ice sotto il ghiaccio marino superficiale e scendono verso acque più profonde durante la maturazione, arrivando come adulti a profondità massime di 400 – 700 m. Nonostante l’assenza di vescica natatoria, l’antarctic silverfish riesce a mantenersi nella colonna d’acqua nello stadio adulto grazie a un tipo di pedomorfia caratterizzato dal mantenimento e dall’aumento dei lipidi presenti nelle fasi larvali e giovanili, che ne aumenta il potere di galleggiamento. Malgrado l’habitus pelagico da adulto, il silverfish è molto efficiente dal punto di vista energetico, possedendo una strategia alimentare simile alle controparti bentoniche, che consiste in questo caso nel galleggiare passivamente nella colonna d’acqua, consumando le prede che capitano nei paraggi, ma senza investire energia in una vera e propria ricerca attiva delle prede. Il fatto di rimanere nella colonna d’acqua durante tutto il ciclo vitale, in combinazione con la strategia di vita passiva, rende l’antarctic silverfish particolarmente suscettibile al trasporto da parte dei sistemi di correnti locali e circumpolari. Questo aspetto lo rende particolarmente interessante nel contesto della biologia di popolazione dei pesci marini, dove risulta importante identificare la presenza di diverse popolazioni e definire l’entità con cui popolazioni separate scambiano individui. In particolare, il fatto che l’antarctic silverfish, che ha una distribuzione circumpolare, presenti o meno una singola popolazione panmittica attorno al continente antartico, rimane una questione aperta. Dato che le fasi larvali sono pelagiche, è ragionevole presupporre che molte specie di nototenioidei siano organizzate in grandi popolazioni omogenee su scala geografica più o meno ampia. Questo presupposto fornisce l’ipotesi nulla da testare quando si investiga la struttura di popolazione di questo gruppo, ed è specialmente rilevante se si considera l’habitus pelagico dell’antarctic silverfish. Il primo studio della struttura genetica di popolazione dell’antarctic silverfish è stato svolto con marcatori del DNA mitocondriale; questa indagine, svolta su una scala circumpolare, non ha fornito evidenze tali da confutare l’ipotesi nulla di panmissia per l’intero oceano antartico. Tuttavia, mentre i confronti svolti tra diverse regioni non sono riusciti a dimostrare la presenza di differenziamento genetico, i confronti svolti entro regioni tra diversi anni di campionamento hanno suggerito l’esistenza di variazione inter-annuale del grado di connettività. Il differenziamento genetico tra anni di campionamento entro la stessa area geografica è riconducibile al fenomeno della chaotic genetic patchiness e può essere dovuto a variazioni nel tasso di reclutamento e mortalità e nell’idrografia. La presenza di differenziamento genetico di popolazione e di chaotic genetic patchiness nell’antarctic silverfish sono stati recentemente confermati mediante genotipizzazione di microsatelliti EST-linked in uno studio focalizzato su campioni provenienti dalla Penisola Antartica. In questo caso, l’utilizzo di marcatori genetici ipervariabili caratterizzati da un elevato potere risolutivo ha permesso di rilevare una significativa struttura genetica sulla scala regionale della Penisola Antartica. Questa tesi di dottorato mira a caratterizzare la struttura di popolazione circumpolare dell’antarctic silverfish, integrando l’informazione fornita dagli studi iniziali con nuovi campioni ed interpretando i risultati alla luce dei diversi aspetti di life history ed idrografia al fine di descrivere i meccanismi di connettività tra popolazioni. Nel primo studio prodotto nell’ambito di questa tesi di dottorato, sono stati analizzati dei campioni di larve dell’antarctic silverfish provenienti dal Mare di Ross, con l’obiettivo di legare l’idrografia locale alla connettività della specie. Lo stato di conservazione dei campioni non ha permesso di utilizzare marcatori molecolari nucleari (microsatelliti) per studiare il differenziamento tra siti geografici entro il Mare di Ross. Nonostante questo, è stato possibile sequenziare un frammento di DNA mitocondriale che ha permesso di identificare univocamente le larve come apparteneneti alla specie P. antarctica. Questo risultato è particolarmente rilevante perché conferma, grazie all’utilizzo di metodi genetici, la presenza di larve della specie P. antarctica in alcune aree del Mare di Ross che erano state precedentemente solo ipotizzate essere zone preferenziali di nursery del silverfish, sulla base di tempi di raccolta dal momento della schiusa delle uova e del tasso di crescita ipotizzato. Sulla base dell’idrografia locale, questo studio ipotizza che la circolazione legata alle depressioni del fondale sia essenziale per il trasporto delle fasi di vita iniziali dalle zone più costiere fino alla scarpata continentale, mentre l’idrografia costiera potrebbe controllare il trasporto lungo i margini della piattaforma continentale modulando la connettività tra popolazioni adiacenti. In un secondo studio prodotto nell’ambito di questa tesi di dottorato sono stati analizzati campioni raccolti nell’arco di 25 anni da sei regioni antartiche diverse: la parte ovest del Mare di Ross, la parte est del Mare di Weddell, la Baia di Larsen, la parte nord della Penisola Antartica, le Isole di South Orkney, e la parte ovest della Penisola Antartica. Questo studio su scala circumpolare è stato condotto utilizzando un pannello di 18 loci microsatellite isolati in precedenza per varie specie di nototenioidei antartici. Questi loci sono risultati polimorfici anche in P. antarctica e informativi per gli obiettivi di questa tesi di dottorato. Alcuni dei campioni inclusi in questo studio sono stati analizzati in due studi precedenti: un primo studio non aveva evidenziato segnali di differenziamento genetico a livello circumpolare (analisi di un marcatore mitocondriale) mentre un secondo studio, più recente e focalizzato sulla Penisola Antartica, aveva segnalato chaotic genetic patchiness e differenziamento genetico utilizzando lo stesso pannello di 18 microsatelliti genotipizzati in questa tesi di dottorato. Questo secondo studio ha confermato che la struttura di popolazione del silverfish sulla scala circumpolare è caratterizzato da alti livelli di flusso genico suggerendo che il sistema di correnti, in particolare l’Antarctic Slope Front and Current System (AFS), abbia un ruolo critico nel collegamento delle popolazioni nell’oceano Antartico. L’importanza del AFS è suggerita dal limitato flusso genico tra le aree ad ovest della Penisola Antartica e le South Orkneys, le due uniche zone non raggiunte dall’AFS. Questa considerazione è ulteriormente supportata dall’ipotesi che l’AFS mantenga la connettività tra depressioni del fondale anche nel Mare di Ross. Per comprendere se l’assenza di differenziamento nell’area ad est del Mare di Weddell fosse effettivamente un fatto biologico o fosse dovuta alla scarsa sensibilità dei marcatori microsatellite a piccole differenze, è stato condotto un ulteriore studio utilizzando l’analisi della chimica degli otoliti di silverfish. La quantificazione delle tracce di elementi deposti nel centro (nucleus) degli otoliti è indicativa delle condizioni chimiche oceanografiche alle quali gli individui sono stati esposti nelle fasi iniziali dello sviluppo. Questa metodologia permette di conseguenza di testare se gli individui siano stati esposti a masse d’acqua diverse nelle prime fasi di vita e di dimostrare l’esistenza di popolazioni con diversa origine. Tra i campioni disponibili per il Mare di Weddell, sono state scelte 5 aree sulla base degli aspetti idrografici che potrebbero influire sulla struttura di popolazione locale (Baia di Atka, Baia di Halley, vicino alla costa di Coats, ad est ed ovest del Filchner Trough). Dati di abbondanza e biomassa raccolti in parallelo durante in campionamento del silverfish nel Mare di Weddell avevano già evidenziato l’importanza del Filchner Trough nel sostenere la popolazione locale dell’antarctic silverfish. Inoltre, l’idrografia locale, attraverso l’intrusione di acqua più calda dall’AFS verso il Mare di Weddell, permetterebbe sia di trasportare il silverfish verso il Mare di Weddell sia di regolare direzionalità e tasso di connettività locale. In contrasto con quanto evidenziato dall’approccio genetico, le analisi di microchimica degli otoliti segnalano differenze statisticamente significative tra gruppi di individui all’interno del mare di Weddell, in particolare tra nordest e sudest del Mare di Weddell. Questi studi suggeriscono un ruolo chiave dell’idrografia sia su scala circumpolare che locale nel modulare la connettività delle popolazioni dell’antarctic silverfish. Inoltre, questa tesi di dottorato evidenzia come un approccio multidisciplinare possa chiarire questioni di connettività di popolazione proponendo una metodologia applicabile a diversi organismi sia antartici che non.

The Eastern Antarctic Dry Valley region is a polar desert, where conditions of extreme aridity, high temperature fluctuations and high irradiation levels make it one of the most extreme environments on earth. Despite the harsh environment, the soils in this region yield a wide range of bacterial and eukaryotic phylotypes in greater abundance than previously believed. In the Dry Valleys, highly localized niche communities colonise the underside of translucent quartz rocks and present macroscopic growth.

Validation of the Regional Climate Model HIRHAM with measurements, especially from radiosondes and GPS-signal-retrieval. Analysis of synoptical structures in Antarctica and comparison of the precipitation in different phases of the Antarctic Oscillation.

The distribution, abundance, chemical composition, metabolism, and feeding ecology of the tentaculate ctenophore, Callianira antarctica (Chun 1897), were investigated during austral winter 2001and autumn & winter 2002, in the vicinity of Marguerite Bay west of the Antarctic Peninsula. Callianira antarctica had a widespread distribution during autumn and winter, and variable abundance (0.02 to 2.6 ind. m-2) during winter 2001 associated with specific circulation features. Size frequency distributions for autumn and winter suggest that more than half of the C. antarctica population may have experienced 'degrowth' during winter due to low food availability. Callianira antarctica is a fairly robust ctenophore with geometric mean (geomean) carbon (C) and nitrogen (N) values of 8.41 and 1.83% dry weight (DW), respectively. Winter oxygen consumption and ammonium excretion rates ranged from 0.059 to 0.410 micro l O2 [mg DW]-1 h-1 and 0.60 to 31.1 µg-at N [g DW]-1 h-1, respectively, at 0oC. Daily minimum maintenance rations based on respiration experiments were 2.7% to 3.6% of the total body carbon (TBC) for small ctenophores, and 1.4% to 1.9% TBC for larger ctenophores. Calanoid copepods and larval and juvenile Antarctic krill were offered to ctenophores in incubation experiments. Digestion times were variable, lasting 8 to 20 h, and were independent of ctenophore size and dependent on number and type of prey. Gut content analysis from one autumn and two winter seasons indicated C. antarctica preyed on both copepods and krill in situ, with an increased dependence on larval krill during winter. Lipid biomarker analysis on C. antarctica and their potential prey confirmed these results. Divers observed aggregations of C. antarctica passively drifting with tentacles extended near dense concentrations of larval Euphausia superba during winter. These observations along with gut content and lipid biomarker analysis suggest that larval krill is an important prey item for C. antarctica during winter.

Includes Organisational Culture Inventory (OCI) and 6 item subscales adapted from the OCI as appendices. Bibliography: leaves 240-255. Investigates the culture of isolated Australian Antarctic stations using qualitative and quantitative research methods. The research also investigated the assessment of person-culture fit within the context of Antarctic station life and culture. Five studies were undertaken on returned Australian Antarctic expeditioners and the results reflect a historical overview of Antarctic station culture from 1950 to 1999.

Mt. Morning is a 2,732 m high, Cenozoic, alkaline eruptive centre situated in the south-west corner of McMurdo Sound in the Ross Sea, Antarctica. Mt. Morning is approximately 100 km south-west of Mt. Erebus, the world's southernmost active volcano. Several Cenozoic, alkali eruptive centres in this region make up the Erebus Volcanic Province. The region is currently undergoing continental extension. Regional-scale, north-striking faulting on the northern flank of Mt. Morning has offset vertical dykes, as young as 3.9 Ma, by up to 6 m dextrally. This is consistent with the trans-extensional regime in the region. The faults also have a dip-slip component, downthrown to the east. These faults define part of the western boundary of the West Antarctic Rift System. Mt. Morning straddles the boundary between the continental rift shoulder of the Transantarctic Mountains in Southern Victoria Land, and the perceived oceanic crust of the Ross Sea. Age determination of the youngest offset dyke constrains movement in the last 3.88 � 0.05 m.y., to an average rate of 0.0015 mm per year. Volcanism on Mt. Morning is divided into two phases. Phase I was erupted between 18.7 � 0.3 and 114 � 0.2 Ma and Phase II between 6.13 � 0.20 and 0.15 � 0.01 Ma. The two phases are separated by a 5.3 m.y. period of quiescence. The geochemistry of Phase I is mildly alkaline; it is composed of volcaniclastic deposits, dykes, sills, and volcanic plugs of nepheline-basanite, nepheline-trachyte, quartz-mugearite, quartz-trachyte, and rhyolite. Phase I rocks evolved along at least two trends: a quartz normative trend, and a nepheline normative trend. Chemical variation in Phase I can be explained in part by crystal fractionation, which has been modelled using major element multiple linear regression. Phase I quartz-mugearite can fractionate to quartz-trachyte after 44% crystallisation. Quartz-trachyte can fractionate to rhyolite after a further 6% erystallisation. The models indicate that clinopyroxene + plagioclase + opaque oxides � alkali feldspar � apatite are the dominant fractionated phases. Many of the Phase I quartz normative volcanic rocks have relatively high ⁸⁷Sr/⁸⁶Sr ratios (0.70501), suggesting that assimilation, most likely of crustal material, has modified them. Phase I nepheline-basanite can fractionate to nepheline-trachyte after 68% crystallisation. Modelling indicates clinopyroxene + nepheline + olivine + opaque oxides are the dominant fractionated phases. Phase II volcanic rocks are strongly alkaline and are mapped as flows, volcaniclastic deposits, dykes, and sills. They have been erupted mainly from parasitic scoria vents and rarely from fissure vents. Rock types include picrobasalt, basalt, basanite, tephrite, hawaiite, mugearite, phonotephrite, tephriphonolite, benmoreite, and phonolite. Chemical variations in the Phase II volcanic rocks can be explained by simple fractionation. Phase II picrobasalt can fractionate to phonotephrite after 78% crystallisation. Phonotephrite can fractionate to phonolite after at least 35% crystallisation, depending on which of several multiple linear regression models are selected. Fractionation is dominated by the removal of clinopyroxene + plagioclase + nepheline + olivine + opaque oxides � apatite � kaersutite. Volcanic rocks in the Erebus Volcanic Province are strongly alkaline on a silica versus total alkalis plot, similar to the Phase II volcanic rocks from Mt. Morning. Mildly alkaline rocks of Phase I are, to date, unique within the Erebus Volcanic Province. Bulk rock isotope ratios of ⁸⁶Sr/⁸⁷Sr (0.70307 - 0.70371 and 0.70498 - 0.70501), �⁴�Nd/�⁴⁴Nd (0.512650 - 0.512902), and �⁰⁶Pb/�⁰⁴Pb (18.593 -20.039) show that the majority of Mt. Morning volcanic rocks lie on a mixing line between HIMU (high-[mu]; enriched in �⁰⁶Pb and �⁰⁸Pb and relatively depleted in ⁸⁶Sr/⁸⁷Sr values) and DM (depleted mantle; high �⁴�Nd/�⁴⁴Nd, low ⁸⁶Sr/⁸⁷Sr, and low �⁰⁶Pb/�⁰⁴Pb). This is similar to the majority of volcanic rocks from the SW Pacific, including Antarctica and New Zealand. Mt. Morning volcanic rocks have tapped this broadly common mantle reservoir. There are variations in radiogenic isotope ratios between Mt. Morning and Mt. Erebus. There are also differences between the incompatible element ratios in volcanic rocks from Mt. Morning, Mt. Erebus, and White Island (a third eruptive centre in the Erebus Volcanic Province), suggesting heterogeneity in the mantle beneath the Erebus Volcanic Province. Significant chemical differences are also noted between ultramafic xenoliths collected from Mt. Morning and from Foster Crater only 15 km away. This suggests a deca-kilometre, possibly even kilometre-scale, heterogeneity in the mantle. Such small-scale chemical differences appear difficult to reconcile with large-scale plume hypotheses for the initiation of volcanism in the Erebus Volcanic Province. Instead, volcanism is much more likely to be related to numerous small plumes, or the preferred hypothesis, metasomatism and amagmatic rifting, followed by decompression melting of upwelling mantle and volcanism during transtensional lithospheric rifting. This latter model is supported by a lack of regional updoming expected with a plume(s), and fits models of localised extension proposed in this thesis. Calc-alkaline and alkaline igneous xenoliths, of felsic to mafic crustal material, have been collected from Mt. Morning. U-Pb geochronology (545.4 � 3.7 Ma and 518.6 � 4.4 Ma) on crustal xenoliths from Mt. Morning illustrate that the basement is Cambrian. Bulk rock chemistry of crustal xenoliths has similarities to compositions reported for Ross Orogen rocks, suggesting the Mt. Morning volcanic edifice is built on a basement that is composed of Cambrian Ross Orogen rock types. Quartz-bearing felsic granulite xenoliths with greater than 70 weight percent silica, collected from Mt. Morning, suggest that part of the basement is felsic. This is the only occurrence of felsic xenoliths reported to date east of the present day coastline of Victoria Land. Mt. Morning crops out less than 25 km from the known northern end of the Koettlitz Glacier Alkaline Province in the Transantarctic Mountains. The partially alkaline basement beneath Mt. Morning suggests the province may continue beneath part of Mt. Morning. The mantle beneath Mt. Morning can be characterised as anhydrous and otherwise largely unmetasomatised, which is atypical of xenoliths collected from the western Ross Sea. Only a handful of Mt. Morning xenoliths show petrographic evidence of metasomatism, these include modal phlogopite, apatite, Fe-Ni sulphide, and plagioclase (in pyroxenite xenoliths), suggesting metasomatising fluids occur discretely in this region. Where present, the metasomatic fluid(s) beneath Mt. Morning are enriched in Ba, LREEs, Th, U, P, Fe, Ni, S, and K, and depleted in Ti relative to the metasomatic fluid composition described at nearby Foster Crater. Oxygen fugacity (fO₂) of the Antarctic shallow mantle has been measured from xenoliths collected from Mt. Morning, where fO₂ was demonstrated to be strongly dependant upon spinel Fe�⁺ content that was measured using Mössbauer spectroscopy, and calculated from the olivine-orthopyroxene-spinel oxybarometer. fO₂ in the rifted Antarctic mantle varies between 0.1 and -1 log units relative to the fayalite-magnetite-quartz buffer and is coupled to melt depletion, with increasing degrees of melt extraction resulting in a more oxidised mantle. This range of upper mantle fO₂ is commonly observed in continental rift settings worldwide. The mantle beneath Mt. Morning is composed of, in increasing degree of fertility, dunite, harzburgite, and lherzolite. Xenoliths representing discrete samples of this mantle have mostly crystallised in the spinel stability field of the mantle at pressures of approximately 15 kb and temperatures between 950 - 970 �C. Symplectites of spinel and pyroxene have been interpreted as petrographic evidence that some of the spinel peridotite originated in the garnet stability field of the mantle. Rare plagioclase-bearing spinel lherzolite (plagioclase lherzolite) is also present in the mantle beneath Mt. Morning, which crystallised at temperatures of between 885 and 935 �C at 5 kb. The Mt. Morning peridotite xenoliths plot along the pre-defined geotherm for the Erebus Volcanic Province, strongly supporting it as the appropriate choice of geothermal gradient for south-west McMurdo Sound. Mineral and bulk rock compositions are nearly identical between the plagioclase lherzolite xenoliths and spinel lherzolite xenoliths. Mineral and bulk rock chemistry suggest it is unlikely that the plagioclase is due to metasomatism. Petrographic evidence and mass balance calculations suggest that the plagioclase lherzolite has crystallised via a sub-solidus (metamorphic) transition from spinel lherzolite upon decompression and upwelling of the mantle. The occurrence of plagioclase lherzolite beneath Mt. Morning could be explained by lithospheric scale uplift along faults that define the western margin of the West Antarctic Rift System. Plagioclase lherzolite has also been collected and described from White Island. White Island is also interpreted to straddle lithospheric scale faults. Rifting and buoyant uplift is sufficient to explain the presence of plagioclase lherzolite in the Erebus Volcanic Province. Plagioclase lherzolite has also been described from Mt Melbourne, an eruptive centre in Northern Victoria Land. Known occurrences of plagioclase lherzolite from the western shoulder of the Ross Sea now cover an area 430 km long and 80 km wide. This is one of the largest provinces of plagioclase peridotite worldwide so far reported.

Despite the apparent pristine conditions and remoteness of Antarctica, persistent organic pollutants (POPs) have been detected in the Antarctic ecosystem since the 1960s. Today, a variety of organic pollutants can be found in Antarctica, often concentrated in local biota. In this thesis I investigate four system input pathways for POPs to Australian Antarctic territory, Eastern Antarctica. This work has been conducted with the purpose of contributing to an understanding of the possible impacts of these pollutants under present and projected climate conditions, as well as establishing robust baselines from which to monitor temporal and spatial trends. The first long range environmental transport (LRET) pathway investigated was the introduction of POP via long range atmospheric transport (LRAT). Transport was assessed via high flow-through passive air sampling at Casey Station between 2009 and 2013, with sample changeover every 1 to 3 months. The results of this study present the first continuous, multi-year sampling effort for POPs originating from the Eastern Antarctic sector. The POP profile presented is distinct from other regions and is characterised by a dominance of agricultural, rather than manufacturing, chemicals, particularly hexachlorobenzene (HCB) and endosulfan. The study also presents the first reported occurrence of endosulfan in air masses on the Antarctic continent, providing evidence of the LRAT capabilities of this compound. Whilst a moderate data timespan of four years is presented, it is projected that continual monitoring at the decadal scale would be required to detect a 5% change in levels with 80% confidence, emphasising the importance of long term monitoring efforts.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
Full Text

In the extreme climate and isolation of Antarctica, much of the built environment exists only as an assemblage of sterile boxes placed in the landscape without consideration of the needs of their occupants or their impact on the environment. In an area of limited resources, an abundance of solar and wind resources is seldom utilized to its full potential. Scientists and support crews spend months at a time living in isolation within the confines of small outposts and stations. Confinement in cramped and impersonal surroundings in this hostile environment can have devastating effects on the health and well-being of research teams and crews. The designs of many facilities rarely venture beyond the minimum programmatic requirements, failing to explore the possibility to become something more. The purely functional engineer's design approach, focusing heavily on initial cost, has been the mainstay of Antarctic architecture until recently. This attitude is beginning to be challenged by designs that focus on sustainability and the psychological impact on their inhabitants. Isolation and climactic conditions should not serve as an excuse for an incohesive atomistic design, but as motivation for a responsible, holistic solution. The technology exists to drastically reduce our negative environmental and carbon footprint in Antarctica by creating more responsible research facilities that fully utilize available renewable energy resources, while providing a superior working and living environment that meets the physical and psychological needs of its occupants. During the austral summer of 2008-2009, the world's first zero emissions polar research station is set to open. The innovative design of the Belgian Princess Elisabeth station can be used as a model for studying the potentials of sustainable and climactically adapted architectural design in Antarctica. I propose to further explore the possibilities of renewable energy, waste management, and prefabrication to design a zero emissions research facility with minimal impact that is responsive to its environment, while adequately providing for the needs of its occupants within the unique and extreme conditions of the Antarctic.

Esta pesquisa teve o objetivo de resgatar, através da memória do trabalhador, seu cotidiano de trabalho na Companhia Antarctica Paulista de Ribeirão Preto/SP. Nesse sentido, foi investigado como o trabalhador foi contratado pela cervejaria e as funções que exerceu; a organização do trabalho e a divisão de tarefas; a rotina do trabalhador e o relacionamento com outros funcionários e com os chefes; o papel do sindicato e as possíveis reivindicações; a importância do trabalho executado e o significado de trabalhar para esta cervejaria e, por fim, o que significou o fechamento da fábrica para aqueles trabalhadores que dedicaram sua vida ao trabalho nesta indústria. Para tanto, foi utilizada a metodologia da História Oral, a partir da realização de entrevistas com ex-funcionários da Companhia Antarctica Paulista, de Ribeirão Preto/SP, escolhidos aleatoriamente, por indicação sucessiva. Após realizadas as entrevistas, foram apresentadas fotografias da fábrica, de produtos e algumas mais atuais do interior de outras fábricas da Antarctica, já que a de Ribeirão Preto já havia encerrado suas atividades para auxiliar o resgate da memória dos entrevistados. Os dados obtidos, a partir da realização das entrevistas, foram analisadas de forma qualitativa, pela qual se buscou aproximações e divergências, tanto de opiniões quanto da realidade apresentada.
This research aimed to rescue, through the memory of the workers, their daily lives working in Antarctica Paulista Company in Ribeirão Preto/SP. In this sense, it was investigated how the workers were hired by the brewery and their functions; the work organisation and the labour Division; the routine of the employees and the relationship among the staff and the chiefs; the role of the Union and the possible workers claims; the importance of the work performed by the workers and the meaning of work for this brewery and, finally, what the ending of the activities of the factory meant to the those workers who have dedicated their lives to the company. To achive this purpose, we used the methodology of Oral history, conducting interviews with former employees of Companhia Antarctica Paulista in Ribeirão Preto/SP, chosen at random, by successive indication. To assist the recovery of memory of the interviewed ones, after the interviews, photographs were presented from the factory, the products and some nowadays photographs from the inner part of other Antarctica factories since the Ribeirão Pretos plant had already closed its activities. The data obtained from carrying out the interviews, were analyzed qualitatively, by which sought both differences and approaches of opinions about the reality presented.

The unique advantages for astronomy on the Antarctic plateau are now well established. In particular, Dome C, Antarctica is potentially one of the best new sites for optical, infrared and sub-millimeter astronomy, presenting the opportunity to build unique astronomical instruments. Located high on the Antarctic plateau, Dome C offers low wind, clear skies, and negligible precipitation. This thesis addresses three additional properties of the site relevant to optical astronomy-sky brightness, atmospheric extinction and optical turbulence. The sky at an optical astronomy site must be dark, and the atmosphere very clean with minimal light extinction. At present little is known from an astronomer's perspective about the optical sky brightness and atmospheric extinction at most Antarctic sites. The high latitude of Dome C means that the Sun spends a relatively small amount of time far below the horizon, implying longer periods of astronomical twilight and less optical dark time than other sites, especially those close to the equator. We review the contributions to sky brightness at high-latitude sites, and calculate the amount of usable dark time at Dome C. We also explore the implications of the limited sky coverage of high-latitude sites, and review optical extinction data from the South Pole. A proposal to extend the amount of usable dark time through the use of polarising filters is examined, and we present the design and calibration of an instrument (called Nigel) to measure the brightness, spectrum and temporal characteristics of the twilight and night sky. The atmospheric turbulence profile above an astronomical site limits the achievable resolution and sensitivity of a telescope. The atmospheric conditions above high plateau Antarctic sites are different to temperate sites; the boundary layer of turbulence is confined very close to the surface, and the upper atmosphere turbulence very weak. We present the first winter-time turbulence profiles of the atmosphere above Dome C, and characterise the site in terms of the achievable precision for photometry and astrometry, and the isoplanatic angle and coherence time for the adaptive optics.

The Republic of Korea (ROK) joined the Antarctic Treaty in 1986 as the 33rd member and became a consultant party in 1989. Despite its geographical remoteness from the region and the geopolitical pressures it faces at home, ROK has made great progress in its scientific research in Antarctica as well as the Arctic. In particular, since the inauguration of the Lee Myung Bak administration in 2008, Seoul has accelerated its commitment to polar research by announcing that it would set up a second permanent base in the Antarctic continent and build a new 7,000 ton ice breaker. South Korea is the 9th largest economy in the world and is now seeking ways to expand its global political influence. The Korean government sees its expansion into Antarctica and the Arctic as part of its path to a greater global leadership role. This thesis explores the reasons behind South Korea’s increased involvement in Antarctica, while referencing the activities of its Arctic programme. It profiles various bodies involved in maintaining and negotiating ROK’s Antarctic presence and voice on Antarctic affairs; it discusses Seoul’s core interests in the Antarctic continent and the polar regions overall, which help to shape its Antarctic policy.

Late Cretaceous angiosperm leaf floras from the Antarctic Peninsula have been studied and described for the first time. The Hidden Lake Formation (Coniacian) and Santa Marta Formation (Santonian-early Campanian) floras were preserved within shallow marine strata exposed on James Ross Island. This area was located at approximately 65°S during the Late Cretaceous. These fossils represent the remains of vegetation growing in the southern high latitudes on an emergent volcanic arc. The plants probably grew on the delta top and along the edge of streams. The leaf fossils are preserved as isolated and fragmentary impressions and although cuticular anatomy is not present, the angiosperm leaves show the well-preserved fine detail of leaf architecture. These leaves have been drawn and described using Hickey's (1979) terminology. Attempts were made to group the leaves into morphotypes to allow reconstruction of floral composition and palaeoclimates. Several methods of grouping leaves were used, including visual grouping, Single character classification, and multivariate approaches. Multivariate statistical analysis allowed many characters to be considered simultaneously and even allowed fragmentary specimens, which were harder to deal with visually, to be evaluated. Clustering analysis was performed and dendrograms were produced for the Hidden Lake Formation and Santa Marta Formation floras, which were used in conjunction with visual assessments to group leaves with distinct morphologies into morphotypes. A total of 41 morphotypes were identified, 30 in the Hidden Lake Formation flora and 31 in the Santa Marta Formation flora, with 20 in common. Detailed descriptions of each morphotype and representative illustrations are presented. Comparisons have been drawn with fossil and living angiosperm leaves. Architectural characteristics suggest that some of the leaves may have affinities with the Cunoniaceae, Lauraceae, Sterculiaceae, Nothofagaceae, Myrtaceae and Elaeocarpaceae. If botanical affinities can be confirmed, many of these occurrences would extend the ranges of angiosperm taxa on the Antarctic Peninsula. Palaeoclimatic interpretation of the leaf floras included comparisons with possible nearest living relatives, analysis of leaf margins, shapes and sizes, and the application of simple linear regression and multiple linear regression models. The climate is considered to have been warm and moist. Mean annual temperature estimates of 12-21°C were provided for the Hidden Lake Formation flora and 14-23°C for the Santa Marta Formation flora. Evaluation of published data suggests that these Coniacian-early Campanian leaf floras may reflect the warmest time during the Cretaceous in Antarctica.

Antarctica provides some of the most extreme environments on earth. Low temperatures, low water availability and nutrient deficiency are contributing factors to the limited colonisation of Antarctic biotopes, particularly in the continental Dry Valleys. The survival of microorganisms in this harsh continent provides the basis for the significance of this study. This study aimed to explore microbial phylotypic diversity across a 500 m altitudinal transect in the Miers Dry Valley, Ross Desert, East Antarctica. The study also attempted to infer from phylogenetic data, the possible presence of indicative phenotypes which might contribute to a functional microbial community.

Soil communities are regarded as among the most complex and diverse assemblages of microorganisms with estimated bacterial numbers in the order of 10â?¹ cells.gâ?»¹
. Studies on extreme soils however, have reported lower cell densities, supporting the perception that the so-called extreme environments exhibit low species diversity. To assess the extent of microbial diversity within an extreme environment, the mineral soils of the Dry Valleys, Ross Dependency, Eastern Antarctica were investigated using 16S rDNA analysis.

Thesis (M.S.)--University of North Carolina at Chapel Hill, 2009.
Title from electronic title page (viewed Oct. 5, 2009). "... in partial fulfillment of the requirements for the degree of Masters of Science in the Department of Geological Sciences." Discipline: Geology; Department/School: Geological Sciences.

The thesis analyses the expedition (TAE) led by Dr.Vivian Fuchs and Sir Edmund Hillary from three vantage points: 1)the years from 1948 to 1955 leading up to the expedition 2) the interaction between the IGY and the TAE projects and 3) the role of the US Navy as the expedition unfolded. The thesis also investigates key events including the purchase of the ship Endeavour from Britain, the competition for leadership of the UK and NZ parties, the 'dash to the Pole' by Hillary, and the search for base sites and routes to the Polar Plateau. The thesis contains an overview historical introduction, a comprehensive literature review as well as a broad-based set of conclusions.

This thesis is concerned with the dynamics of the middle atmosphere over the southern-most continent on our planet, Antarctica. Building on previous observational and theoretical efforts to understand the dynamics of this region of the atmosphere, the work encompasses instrument improvements as well as data analysis studies of gravity waves in the lower and middle stratosphere, tides in the upper mesosphere and lower thermosphere, and short-period planetary waves in the stratosphere and mesosphere. An upgrade of the Medium-Frequency Spaced Antenna (MFSA) radar at Scott Base, Antarctica, was carried out in 2004/5 in order to ensure continued operation and enhance its capabilities to measure gravity waves. As a result, the quality of the wind measurements was greatly enhanced and the amount of data collected is now greater by a factor of approximately 15 compared with before the upgrade. Analysis of over two decades of wind velocity data from Scott Base yields a reliable climatology of the dynamics of the upper mesosphere and lower thermosphere in this area, namely the tidal oscillations and the background winds. In addition, interannual variability is assessed and periodicities of approximately 11 years and strong positive trends in tidal amplitudes are reported. Mechanisms that could explain the observed behaviour are proposed. The data are then combined with wind measurements from Halley, the longitudinal conjugate site, in order to study the zonal character of the semi-diurnal tide. Zonal wavenumber 1 and 2 waves are both found and mechanisms that could explain the generation of a wavenumber 1 component are suggested. Two further sets of MFSA radar wind measurements are used to investigate the behaviour of planetary waves with periods of between two and four days in the Antarctic middle atmosphere. Satellite temperature measurements further help to create a more complete picture of these waves. Baroclinic and barotropic instabilities, which result from shears of the zonal wind, appear to be responsible for much of the observed wave activity. In addition, a quasi-to day wave event in mid-May 2005 with unusually large amplitudes is examined and suggested to be linked to a solar proton event. Gravity wave activity over Antarctica is studied using temperature profiles obtained through the satellite radio occultation technique. Although the measurements are restricted to below 35 km altitude, high-resolution temperature profiles allow conclusions to be drawn about the seasonal, geographical, and height distribution of gravity wave activity. Mountain waves are found to be important over the Antarctic Peninsula and the Transantarctic mountains where they contribute more than 20% of the observed wave activity in the lower stratosphere. In addition, the analysis indicates the importance of critical-level filtering and Doppler-shifting.

Antarctic ice shelves play a key role in the global climate system, acting as important sites for the cooling of shelf waters, thereby facilitating deep and bottom water formation. Many of the processes that take place under large ice shelves can be observed more conveniently beneath smaller ice shelves such as Fimbul Ice Shelf, an ice shelf in the eastern Weddell Sea. Fimbul Ice Shelf and nearby ice shelves might also play a significant regional role: although no bottom water is produced in this area, it is thought that Fimbul Ice Shelf and nearby ice shelves precondition the shelf waters that ultimately are converted to Weddell Sea Deep Water (WSDW) in the southern Weddell Sea. Using the first data ever to be collected beneath an ice shelf from an autonomous underwater vehicle (AUV), as well as data from the vicinity of the ice shelf using traditional oceanographic methods, this thesis discusses the circulation and processes occurring beneath the ice shelf. This has been supplemented by using a coupled ice shelf/ocean model, POLAIR, to simulate the circulation, melting, and tides under Fimbul Ice Shelf and in the surrounding area. Data from the ice shelf cavity show relatively large variability in temperatures, but all within approx. 0.25 °C of the freezing point. Melt rates are found to be lower than some previous model studies, but in better agreement with observations and glaciological models. The base of the ice shelf was found to be rough in places, corresponding to `flow traces' visible in satellite imagery. This could have implications for mixing beneath the ice shelf, at least in these limited areas. The Autosub AUV was found to be a useful platform for measuring hydrography and ice shelf cavity geometry with spatial coverage and resolution not available from surface measurements.

The thesis deals with the marketing strategy of Brazilian brand of soft drinks Guaraná Antarctica. Fisrt it describes the brand marketing strategy in the domestic market in Brazil and its entry to international markets. Furthermore the thesis analyzes market opportunities of this brand of drinks with guarana extract in Czech Republic and evaluate the trasfer of marketing strategies to Czech environment. As a result changes to the marketing strategy in order to improve brand's position on the Czech market are proposed.

The research presented in this dissertation focused on the microbial ecology of the subglacial discharge from the Taylor Glacier in the McMurdo Dry Valleys, Antarctica. The major objectives of my research were to 1) define the biogeochemistry of the subglacial outflow 2) describe the microbial diversity of the subglacial outflow and 3) examine the impact of subglacial outflow on the geochemistry and biology of the west lobe of Lake Bonney, a lake that abuts the glacier. The subglacial outflow from the Taylor Glacier is known as Blood Falls owing to a visible accumulation of iron-oxides at the point where it flows from the snout of the glacier. The subglacial reservoir is thought to originate from the Pliocene Epoch (~5 Mya) when the dry valleys were fjordlands. The episodic release of subglacial water at Blood Falls provides a sample of what is believed to be ancient seawater trapped in the upper Taylor Valley and eventually covered by the Taylor Glacier as it advanced. Biogeochemical measurements, culture-based techniques, and molecular analysis (based on 16S rDNA sequences), were used to characterize microbes and chemistry associated with the subglacial outflow. Culture and molecular-based techniques, along with geochemical data, indicate the presence of a diverse chemoautotrophic and heterotrophic bacterial assemblage that utilizes iron and sulfur minerals for growth. 16S rDNA clone library phylotypes and cultured isolates were related to organisms that inhabit permanently cold environments. The biological and geochemical component of the ancient outflow changes as it travels from the subglacial environment to the moat of the west lobe of Lake Bonney and eventually into the saline deep water in the lake proper. The bottom water of the west lobe of Lake Bonney is geochemically similar to ancient subglacial outflow, but the microbial diversity in the two systems is distinct, and ancient subglacial brine does not appear to provide the microbial seed for the deep water of Lake Bonney. Collectively, my data indicate that the habitat beneath the Taylor Glacier harbors a functional microbial ecosystem that utilizes chemosynthetic and heterotrophicactivity to obtain carbon and energy in the absence of light.

The Antarctic ice sheet is increasingly contributing to sea-level rise because of accelerated mass losses at its floating extensions -- its ice shelves. By floating while remaining attached to the grounded ice sheet, ice shelves buttress (i.e. restrain) the inland ice in such a way that ice-shelf losses lead to accelerated ice discharge in the ocean. This thesis investigates the stability of Antarctic ice shelves -- so crucial for the stability of the entire ice sheet -- using the Roi Baudouin Ice Shelf (RBIS), Dronning Maud Land, East Antarctica, as a case study. The RBIS has remained relatively stable over the last millennia and presents various kilometre-scale features (pinning point, ice-shelf channels and englacial lakes) with potential impact on its present and future stability.We first derive a horizontal velocity field, combining interferometry and speckle tracking with Synthetic Aperture Radar images from ERS 1/2 and ALOS-PALSAR, respectively. The resulting velocities and associated shear-strain rates represent the most detailed fields, currently available for the RBIS and clearly resolve small-scale features of the RBIS: significant slow-down and shearing are observed upstream of a small pinning point and ice converges at ice-shelf channels. We then combine our flow field with high-resolution elevations from TanDEM-X to infer the Basal Mass Balance (BMB) of the RBIS. This method relies on mass conservation in a Lagrangian frame and enables us to finely detect spatial variability in the BMB. We show that the BMB of the RBIS varies substantially on sub-kilometre scales. Our technique is promising and could easily be applied more widely.Additionally, the flow field is used to investigate how considering/ignoring small pinning points in observations (geometry and velocities) impacts data initialisation of poorly known parameters (e.g. basal friction, ice viscosity) and subsequent ice-sheet modelling with BISICLES. We find that overlooking the pinning point in the bathymetry leads to erroneous ice-shelf properties whereas accurately capturing the pinning point in velocities is of secondary importance. Finally, before concluding the thesis, we discuss the stability of the RBIS and its neighbouring ice shelves. Most studies agree that the ice shelf has remained stable over the last decades to millennia and would likely remain so in the absence of external forcing. We however point out to three potential triggers of instabilities: (i) large quantities of surface meltwater are formed in the grounding zone and subsequently stored on the ice shelf, thereby providing fuel for hydrofracturing; (ii) ice-shelf channels are found to significantly incise the ice inland and (iii) a bathymetric trough beneath the RBIS forms a potential gateway for warm water intrusions the ice-shelf cavity, which could destabilise the ice shelf from below. We close with a short essay on the importance of outreach, where we argue that public engagement as a scientist should be considered as being part of science and should be valued for its worth. This chapter gives us the opportunity to present outreach activities undertaken in the frame of this thesis. We conclude that, just like ice shelves control Antarctic ice losses, science communication determines transfers of scientific expertise to public knowledge.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished

In this thesis RNA-sequencing tools are applied on some representatives of the antarctic trophic chain exposed to a non lethal temperature increase, as to understand and model their response to the increase in temperature expected to happen in this decade, in order to extend eventual functional conclusions to other temperate stenotherm organisms such as those living at extreme depths. RNA-sequencing consists in a set of powerful and sensible tools that allow qualitative and quantitative measurements in gene expression, pairing molecular analyses with state-of-the-art statistics and computer science. The aforementioned sensitivity, in synergy with a proper experimental design, allowed studying not only the response to a temperature increase, but also to the experimental condition itself (i.e. stabling of wild animals in tanks). The notothenioid fish Trematomus bernacchii (from which muscle, gills and brain were sampled), the scallop Adamussium colbecki (from which gills, mantle and digestive gland were sampled), the amphipod Pseudorchomene plebs and the tardigrade Acutuncus antarcticus are the models of choice of this work. In particular T. bernacchii was the most responsive of the bunch, specially in the brain tissues, where the temperature (+1.5°C increase) induced upregulation of genes involved in immune response and inflammatory state after 7 days of exposure. After 20 days of heat exposure many pathways related to synapse function and structure were altered, suggesting an on-going profound alterations in the tissue, which may also be the result of the combined effect of heat and the impossibility to avoid it in captivity. Even more profound effects were observed in the response to time in experimental tanks, as an important shift in gene expression was observed in the brain, suggesting profound changes in the neural pathways, including those involved in specific stress perception. The scallop A. colbecki did not show significant change in gene expression patterns in response to heat, but a small change was observed in the digestive gland after 20 days of experimental captivity, showing alterations in genes whose functions are mainly involved in feeding ability. Samples from the amphipod P. plebs were challenging to prepare and to analyze, as many were lost due to unfreezing during transport. Moreover the presence of a bycatch of Eusirus cf. giganteus juvenile and an high degree of parasitism from a dinoflagellate of the genus Hematodinium in all samples made it impossible to study the response of the amphipod to a warmer environment. Nevertheless, the transcriptomic data allowed the identification of an high expression of hemocyanin in E. giganteus suggesting a possible cold adaptation trait, the classification of our samples as a Orchomenid cryptic species, and the first identification of active Hematodinium parasitism in the antarctic ocean. Finally the tardigrade A. antarcticus displayed a striking sample variability, that may underlie an never described genomic variability and/or an high level of heterozygosity. This fact reduced the number of samples in the differential expression analysis, which nevertheless showed a response to short term exposure to heat with a pattern proportional to temperature in terms of fold changes of gene expression levels. The differentially expressed genes suggested that mitochondrial oxidative metabolism increased and hinted the activation of pathways related to resistance forms typical of the Tardigrada phylum. Such a response was not observed in a long term exposure to the higher temperatures, suggesting that the changes observed in short term are compensatory. ​

Investigating openwork block accumulation has the potential to further our understanding of rock weathering, the control of geological structure on landforms, the production of substrates for biological colonisation and the impacts of climate change on landform development and dynamics. Various models for the development of these landforms have been proposed. This includes in situ weathering, frost heave and wedging. Furthermore, it has been suggested that cold-based ice has the potential to preserve these features rather than to obliterate them. Blocky deposits are also frequently used as proxy evidence for interpreting palaeoclimates. The morphology and processes acting on a blockfield located on the Northern Buttress of the Vesleskarvet Nunataks, Dronning Maud Land, Antarctica (2°W, 71°S) were investigated and characterised. Given block dimensions and orientations that closely resembled the parent material and only small differences in aspect related characteristics observed, the blockfield was found to be autochthonous with in situ block production and of a young (Holocene) age. Small differences in rock hardness measurements suggest some form of aspect control on rock weathering. South-facing sides of clasts were found to be the least weathered. In comparison, consistently low rock hardness rebound values for the north-facing aspects suggest that these are the most weathered sides. Additional indicators of weathering, such as flaking and pitting, support analyses conducted for rock hardness rebound values. Solar radiation received, slope gradients and snow cover were found to influence weathering of clasts across the study site. Furthermore, ambient temperatures and wind speed significantly influenced near-surface ground temperatures dynamics. However, the lack of a matrix and paucity of fine material in textural analyses suggest a limited weathering environment. It is suggested that the retreat of the Antarctic ice sheet during the last LGM led to unloading of the surface, causing dilatation and subsequent fracturing of the bedrock along pre-existing joints, leading to in situ clast supply. Subsequent weathering and erosion along other points or lines of weakness then yielded fines and slight edge rounding of clasts.

Subglacial water plays an important role in the regulation of an ice sheet's mass balance. It may be the dominant control on the velocities of ice streams and outlet glaciers on scales of months to millennia. Recent satellite observations of ice surface elevation changes have given researchers new insights into how subglacial water is stored and transported. Localized uplift and settling of the ice surface implies that lakes exist beneath the ice sheet that are being filled and drained on relatively short time scales. %At the base of an ice sheet water can be transported through a variety of drainage networks or stored in subglacial lakes. Here, a numerical investigation of the mechanisms of transport and storage of subglacial water and the associated time scales is presented. Experiments are carried out using a finite element model of coupled ice and water flow. The first experiment seeks to understand the relationship between the depth of a basal depression and the area over which the feature affects basal water flow. It is found that as the perturbation to a topographic depression's depth is increased, water is rerouted in response to the perturbation. Additionally it is found that the relationship between perturbation depth and the extent upstream to which its effects reach is nonlinear. The second experiment examines how the aspect ratio of bed features (prolate, oblate, or equidimensional) influences basal water flow. It is found that the systems that develop and their interactions are mediated by both the topography and the feedbacks taken into account by the coupling of the systems in the model. Features oriented parallel to ice and water flow are associated with distributed fan systems that develop branches which migrate laterally across the domain and interact with one another on monthly and yearly timescales. Laterally oriented features develop laterally extensive ponds. As the ratio of longitudinal to lateral dimension of the topography is increased, a combination of these two water distributions is seen.