A warming Southern Ocean (SO), due to climate change and global warming, has many implications on the sub-Antarctic Islands in the SO. Due to the distance away from continental land these islands experience an oceanic climate, making them the perfect sentinels to climate change in this sector of the Southern Ocean. Studies have proposed that climate changes reported at the Prince Edward Islands (PEIs) correspond in time to a southward shift of the Antarctic Circumpolar Current (ACC) particularly the Subantarctic Front (SAF). While other studies have shown distinctive trends in ocean and atmospheric parameters such as sea surface temperature (SST), air temperature, sunshine, rainfall, air sea level pressure and wind speed and direction from the 1950s to the early 2000s, the aim of this study is to update those studies to a more recent time with updated time series. Among the changes recorded is an increase in SST and air temperature, which is a strong indication of the changing local and global climate. Using linear regression, this study showed that the rates of increase from 1949 to 2018 of the SST (0.022°C/year), minimum (0.0072°C/year) and maximum air temperatures (0.016°C/year) are smaller than estimated in previous studies. The increasing trend in SST and air temperature reported by previous papers has actually stopped since the 2000s, which reduces the formerly reported trend (0.028°C/year). Although the in-situ measured SST data had gaps, a good correlation with in-situ SST and large scale satellite derived Reynolds SST help to corroborate the covariation between SST, in-situ SST and air temperature giving weight to the hypothesis of a reversal of the positive temperature trends reported by others. The change in decadal variability a decrease in air pressure of 4 hPa since the late 1990s to late 2000s, which coincided with a decrease in minimum and maximum air temperatures of 1°C over the same period; decrease in westerly wind and an increase in the northerly component of the wind, which would explain the decrease of inshore sea surface temperature a while thereafter. This study further corroborates previous findings of a continued decrease in rainfall, while the sunshine has largely remained the same. The seasonal cycle of the air pressure is significantly associated with that of rainfall, showing that the bimodal high air pressure signature resulting from the Semi-annual Oscillation (SAO) is associated with a decrease in rainfall. The Southern Annual Mode (SAM) was significantly yet weakly correlated with the SST (0.24), rainfall (-0.25) and air pressure (0.16), indicating that it does have an impact at the PEIs but not as strong as previously speculated. The El Niño Southern Oscillation (ENSO) has very weak and insignificant relationships with the parameters examined except for a weak relationship with in-situ SST, sunshine and air pressure. These new insights, especially at the decadal timescale, could further our insight on how subAntarctic islands have responded to climatic changes.

No description available.

No description available.

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The global climate is strongly regulated by the oceans, which store carbon away from the atmosphere for long periods. In an effort to understand the role of the oceans in the carbon cycle, it is necessary to understand the nuances of specific regional and functional marine ecosystems. The continental shelf of the West Antarctic Peninsula (WAP) is one particularly important regional ecosystem that plays a vital role in the Southern Ocean carbon export. Within the seasonally productive marginal ice zone of the WAP, I sought to identify the long-term drivers of particulate organic carbon (POC) flux. The vast majority of exported POC on the WAP was previously found to be made up of krill fecal pellets. I provide evidence that supports the hypothesis that the inherent life cycle of krill drives the observed 5-year oscillation in POC export. At the end of their life cycle, when krill are at their largest body size, the WAP experiences anomalously high POC export events through the production and sinking of large, carbon-rich krill fecal pellets. Conversely, when krill are young and small, POC export is anomalously low. This pattern shows that ecology exerts a first-order control on the the biogeochemical cycles of the WAP. Upon identifying the source and driver of POC export on the WAP, I set out to determine the role heterotrophic bacteria play in POC flux attenuation. I collected krill fecal pellets on the WAP over three years and measured bacterial metabolic activity in terms of bacterial production and respiration, thereby identifying the amount of organic carbon within the sinking fecal pellets that is lost due to bacteria. Overall, fecal pellet POC turnover rate by bacteria is very low. The relationship between bacteria and POC is complex with each having an affect on the other. Despite varied reactions of the free-living bacterial populations to the presence of krill fecal pellets, a consistent pattern emerged in the concentration of nucleic acid within each bacterial cell. Access to fecal pellets increased the metabolic activity of the free-living bacterial population. This finding shows that the egestion of krill fecal pellets metabolically stimulates the surrounding bacterial community, even though bacteria play a minor role in fecal pellet POC flux attenuation. Though bacteria were found to play a minimal role in organic carbon uptake on krill fecal pellets, they are still vital members of the WAP ecosystem and biological pump. I next sought to identify which bacteria in particular were responsible for colonizing and consuming the fecal pellet POC. Krill fecal pellets were genetically sequenced after timed exposure to the free-living water column bacterial community. I found that there is an endemic population of bacteria that are associated with each population of krill and their fecal pellets. This community of fecal pellet-associated bacteria does not change over time, indicating little colonization by free-living bacteria. Krill fecal pellets, aside from being good agents of POC export, seem to be selective environments for certain specialized copiotrophic bacteria. Further, I find that only a small subset of these endemic copiotrophs actively partake in carbon consumption on krill fecal pellets. Overall, these results show that a small endemic, specialized bacterial community play an outsized role in krill fecal pellet POC degradation and flux attenuation, but that krill fecal pellets remain efficient agents of carbon export to the deep ocean.

Early 1990s to late 2000s freshening (ΔS ≈ -0.001–0.002) and warming (Δθ ≈ 0.02°C–0.035°C) of bottom waters was detected in the southern Pacific Ocean, and Ross Sea source waters progressively freshened during the past four decades. This study investigates potential freshwater anomaly sources and quantifies their effect. Glacial melt water inputs to the GCT increased by 1.3 km^3 per decade (1976– 2007), more rapidly so after 2000 (6.8 km^3 per decade), freshening local Shelf Water by 0.0004 per decade. Lighter basal melt inputs to the LAT started in 1994 and also picked up after 2000 to 14.9 km^3 per decade, lowering the local Antarctic Surface Water salinity by -0.017 per decade. Upstream in the Amundsen Sea surface water freshened by -0.03 per decade (1994–2007) mostly (50%) from larger melt water inputs from the Pine Island (17.7 km^3 per decade) and Dotson (14.8 km^3 per decade) glaciers. Two decades of steady (1978-2000) strengthening of sea ice productivity (200 km^3 per decade) within the Ross Sea Polynya suddenly reversed to weakening (-98.6 km^3 per decade) and resulted in Shelf Water freshening (-0.02 per decade) thereafter. To fully account for the observed variability in Ross Sea waters, the progressive (1992- 2011) adjustment of the density field and induced advective contributions are estimated based on a simplified three-layer stratification. Eastern (western) inflow (outflow) of light surface (dense shelf) water increased by 28% (15%) to 1.11 Sv (1.01 Sv) by 2011; whereas a sluggish intermediate inflow (0.02 Sv) of Modified Circumpolar Deep Water turned into outflow after 2007, thus contributing 0.09 Sv by 2011 to the ventilation of deep waters farther offshore. The estimated evolution of overturning and advective salt fluxes in the Ross Sea yield overall freshening of water masses similar to those derived from observations. Volumetric mean salinities declined at -0.07 per decade for Antarctic Surface Water, -0.05 per decade for Modified Circumpolar Water, and -0.03 per decade for Shelf Water. Outflow intensification of Shelf Water mixtures is also consistent with bottom water property changes (freshening and warming) measured farther downstream in the southern Pacific Ocean.

Bibliography: leaves 194-212. / ix, 214 leaves : ill. (some col.) ; 31 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Mawson Institute for Antarctic Research, 1991

Esta tese aborda a definição de um projeto estratégico-científico brasileiro para a Antártida, a partir da análise da evolução da geopolítica do Sistema do Tratado Antártico (STA). A questão antártica, conforme esta tese, se fundamenta em dois pressupostos teóricos antagônicos das relações internacionais, o realismo e o liberalismo. As premissas de cooperação científica e de uso pacífico da região, estabelecidos no Tratado da Antártida (1959), determinaram a discussão do objeto de estudo a partir de uma epistemologia liberal. A geopolítica antártica, neste início do século XXI, pende para uma dialética científico-ambiental, em detrimento da dimensão econômico–territorialista que dominou o discurso para a região austral até o emblemático ano de 1991, quando ocorreu a ratificação do Protocolo sobre Proteção Ambiental do Tratado da Antártida (Protocolo de Madri). Se o século XX foi marcado pelo advento da ciência antártica, representado pelo Ano Geofísico Internacional (1957 - 1958), o presente século se caracteriza, até o momento, como aquele em que essa ciência antártica deverá construir sua própria agenda. Os Estados-signatários, cada vez mais, reconhecem o peso político de uma ciência antártica de excelência dentro do STA. Com a instituição do Programa Antártico Brasileiro (PROANTAR), em 1982, o país passou a defender seus substanciais interesses naquela região, que, em um primeiro momento, estavam subordinados às contingências da Guerra Fria e ao Projeto do Brasil-potência. Todavia, a invocação subjetiva de tais interesses não permitiu que se delimitasse a sua real amplitude. Esse posicionamento geopolítico em relação à Antártida começou a ser referenciado a partir de 2011, quando a questão antártica, através da elaboração de um Planejamento Estratégico para o PROANTAR (2012 - 2022), passou a assumir uma relativa importância estratégica para o país; em outras palavras, o programa aproximou-se de um projeto de Estado. No referido planejamento encontram-se as diretrizes que deverão garantir ao Brasil um status político relevante dentro do STA, o que implica numa participação efetiva do país nas decisões sobre o destino daquela região. A diretriz principal desse processo é a inserção do país no seleto grupo de Estados-signatários que desenvolve pesquisas de ponta na Antártida. Ao Entender a importância estratégico-geopolítica da Antártida para o Brasil, e o protagonismo da ciência na política do STA, esta tese propõe novos desafios e paradigmas à ciência antártica brasileira, apoiando o atual Planejamento Estratégico para o PROANTAR (2012 - 2022) e o mais recente Plano de Ação para a Ciência Antártica (2013 - 2018). Assim, analisar o PROANTAR a partir da definição de um projeto estratégico-científico, e suas repercussões geopolíticas, é o objetivo maior desta tese, implicando nas seguintes metas: uma análise sobre a geopolítica antártica, o que determinou uma discussão preliminar sobre os pressupostos geopolíticos do Tratado e da ciência antártica, a partir de uma perspectiva histórica; uma análise sobre as dimensões da geopolítica da região no limiar do século XXI, identificando o ano de 1991 (ratificação do Protocolo de Madri) como o momento de inflexão do STA, no qual a dimensão científico-ambiental começou a adquirir maior relevância geopolítica; uma análise sobre a questão antártica no pensamento geopolítico brasileiro, que permitiu discorrer sobre a construção de um possível imaginário territorialista antártico, assim como a sua repercussão na dimensão científica do PROANTAR. Por fim, se analisa os novos desafios à ciência antártica brasileira no século XXI: a expansão geográfica das pesquisas do PROANTAR naquele continente, em especial as investigações no interior do manto de gelo antártico, que quebra o paradigma de uma ciência periférica, historicamente restrita à região da Península Antártica; e a instituição de uma política capaz de garantir a qualidade da produção científica, através de um adequado apoio logístico-financeiro. Vencer tais desafios é de importância fundamental para a inclusão da pesquisa antártica brasileira nas chamadas fronteiras emergentes da ciência. Todavia, à medida que se analisa as ações político-científicas, convergentes à definição de um projeto estratégico brasileiro para a Antártida, que vêm sendo implementadas desde o início deste século, mais nítida se tornam as contradições e os obstáculos à definição de tal projeto: os entraves burocráticos e a volatilidade das ações políticas, que, somados a falta de reconhecimento da importância (geo)política de uma ciência antártica de vanguarda, em particular por grande parte dos pesquisadores que atuam no PROANTAR, impedem a instituição de uma política científica e a definição de um projeto estratégico-científico para a região. / This thesis addresses the definition of a Brazilian strategic-scientific project for Antarctica from the analysis of the Antarctic Treaty System (ATS) geopolitical evolution. The Antarctic question, as discussed in this thesis, is based in two antagonistic theoretical premises taken from the foreign relations (realism and liberalism). The premises of scientific collaboration and the pacific use of the region, established in the Antarctic Treaty (1959), determined a discussion of this topic using a liberal epistemology. The Antarctic geopolitics at the beginning of the 21st century leans towards a scientific-environmental dialectics, to the detriment of the economical-territorial dimension that dominated the discourse for the Austral region up to the emblematic year of 1991, when the Protocol on Environmental Protection to the Antarctic Treaty (Madrid Protocol) was ratified. If the 20th century was marked by the arrival of the Antarctic science, represented by the International Geophysical Year (1957-1958), the current century is characterized, so far, as the one in which the Antarctic science should build its own agenda. The Signatory-States increasingly recognize the political weight of an Antarctic science of excellence within the ATS. By establishing the Brazilian Antarctic Program (PROANTAR, from the Portuguese Programa Antártico Brasileiro) in 1982, Brazil started to defend of its substantial interests in the Antarctic region. These interests, at first, were subordinated to the Cold War contingencies and the Brazil-potency Project. However, the subjective invocation of such interests did not allow the delimitation of its real extent. This geopolitical positioning in relation to Antarctica was first mentioned in 2011 when the Antarctic question, through the preparation of a Strategic Planning for PROANTAR (2012 - 2022), acquired a relative strategic importance for the country. In other words, the program became closer to a project of State. This plan contains directives that shall grant a relevant political status to Brazil within the ATS, which implies the effective participation of the country in the decisions about the fate of the region. The integration of the country into the select group of signatory States that develop cutting-edge research in Antarctica is the main directive of this plan. By understanding the strategic-geopolitical importance of Antarctica to Brazil, and the role of science in the ATS politics, this thesis proposes new challenges and paradigms to the Brazilian Antarctic science, supporting to the current Strategic Planning for PROANTAR (2012 - 2022) and the most recent Action Plan for the Antarctic Science (2013 - 2018). Thus, the analysis of PROANTAR from the perspective of the definition of a strategic-scientific project and its geopolitical repercussions are the main objetives of this thesis, which are reflected in the following goals: an analysis of the Antarctic geopolitics, which determined a preliminary discussion regarding the geopolitical premises of the Treaty and the Antarctic science from a historical perspective; an analysis of the geopolitical dimensions of the region at the benning of the 21st century, identifying the year 1991 (ratification of the Madrid Protocol) as the ATS turning point, when the scientific-environmental dimension began to acquired a greater geopolitical relevance; an analysis of the Antarctic question in the Brazilian geopolitical line of thought, which allowed the discussion about the construction of a possible Antarctic territorial imaginary, as well as its repercussion on the scientific dimension of PROANTAR. Finally, we analyze the new challenges to the Brazilian Antarctic science in the 21st century: the geographic expansion of the PROANTAR research in that continent, especially the investigations into the Antarctic ice sheet, breaking the paradigm of a peripheral science that has been historically confined to the Antarctic Peninsula region; and the institution of a policy that guarantees the quality of the scientific production through an adequate logistic-financial support. Overcoming such challenges is paramount for the inclusion of the Brazilian Antarctic research in the so-called emerging frontiers of science. Nonetheless, as we analyze the political-scientific actions, converging to the definition of a Brazilian strategic project for Antarctic, which has been implemented since the beginning of the century, it becomes clearer the contradictions and obstacles to the definition of such project become: the bureaucratic hindrances and the volatile political actions, which in addition to the lack of recognition of the (geo)political relevance of a cutting-edge Antarctic science, especially by a large part of the scientific community working at PROANTAR, prevent the institution of a the scientific politicy and the definition of a strategic-scientific project for the region.

Esta tese aborda a definição de um projeto estratégico-científico brasileiro para a Antártida, a partir da análise da evolução da geopolítica do Sistema do Tratado Antártico (STA). A questão antártica, conforme esta tese, se fundamenta em dois pressupostos teóricos antagônicos das relações internacionais, o realismo e o liberalismo. As premissas de cooperação científica e de uso pacífico da região, estabelecidos no Tratado da Antártida (1959), determinaram a discussão do objeto de estudo a partir de uma epistemologia liberal. A geopolítica antártica, neste início do século XXI, pende para uma dialética científico-ambiental, em detrimento da dimensão econômico–territorialista que dominou o discurso para a região austral até o emblemático ano de 1991, quando ocorreu a ratificação do Protocolo sobre Proteção Ambiental do Tratado da Antártida (Protocolo de Madri). Se o século XX foi marcado pelo advento da ciência antártica, representado pelo Ano Geofísico Internacional (1957 - 1958), o presente século se caracteriza, até o momento, como aquele em que essa ciência antártica deverá construir sua própria agenda. Os Estados-signatários, cada vez mais, reconhecem o peso político de uma ciência antártica de excelência dentro do STA. Com a instituição do Programa Antártico Brasileiro (PROANTAR), em 1982, o país passou a defender seus substanciais interesses naquela região, que, em um primeiro momento, estavam subordinados às contingências da Guerra Fria e ao Projeto do Brasil-potência. Todavia, a invocação subjetiva de tais interesses não permitiu que se delimitasse a sua real amplitude. Esse posicionamento geopolítico em relação à Antártida começou a ser referenciado a partir de 2011, quando a questão antártica, através da elaboração de um Planejamento Estratégico para o PROANTAR (2012 - 2022), passou a assumir uma relativa importância estratégica para o país; em outras palavras, o programa aproximou-se de um projeto de Estado. No referido planejamento encontram-se as diretrizes que deverão garantir ao Brasil um status político relevante dentro do STA, o que implica numa participação efetiva do país nas decisões sobre o destino daquela região. A diretriz principal desse processo é a inserção do país no seleto grupo de Estados-signatários que desenvolve pesquisas de ponta na Antártida. Ao Entender a importância estratégico-geopolítica da Antártida para o Brasil, e o protagonismo da ciência na política do STA, esta tese propõe novos desafios e paradigmas à ciência antártica brasileira, apoiando o atual Planejamento Estratégico para o PROANTAR (2012 - 2022) e o mais recente Plano de Ação para a Ciência Antártica (2013 - 2018). Assim, analisar o PROANTAR a partir da definição de um projeto estratégico-científico, e suas repercussões geopolíticas, é o objetivo maior desta tese, implicando nas seguintes metas: uma análise sobre a geopolítica antártica, o que determinou uma discussão preliminar sobre os pressupostos geopolíticos do Tratado e da ciência antártica, a partir de uma perspectiva histórica; uma análise sobre as dimensões da geopolítica da região no limiar do século XXI, identificando o ano de 1991 (ratificação do Protocolo de Madri) como o momento de inflexão do STA, no qual a dimensão científico-ambiental começou a adquirir maior relevância geopolítica; uma análise sobre a questão antártica no pensamento geopolítico brasileiro, que permitiu discorrer sobre a construção de um possível imaginário territorialista antártico, assim como a sua repercussão na dimensão científica do PROANTAR. Por fim, se analisa os novos desafios à ciência antártica brasileira no século XXI: a expansão geográfica das pesquisas do PROANTAR naquele continente, em especial as investigações no interior do manto de gelo antártico, que quebra o paradigma de uma ciência periférica, historicamente restrita à região da Península Antártica; e a instituição de uma política capaz de garantir a qualidade da produção científica, através de um adequado apoio logístico-financeiro. Vencer tais desafios é de importância fundamental para a inclusão da pesquisa antártica brasileira nas chamadas fronteiras emergentes da ciência. Todavia, à medida que se analisa as ações político-científicas, convergentes à definição de um projeto estratégico brasileiro para a Antártida, que vêm sendo implementadas desde o início deste século, mais nítida se tornam as contradições e os obstáculos à definição de tal projeto: os entraves burocráticos e a volatilidade das ações políticas, que, somados a falta de reconhecimento da importância (geo)política de uma ciência antártica de vanguarda, em particular por grande parte dos pesquisadores que atuam no PROANTAR, impedem a instituição de uma política científica e a definição de um projeto estratégico-científico para a região. / This thesis addresses the definition of a Brazilian strategic-scientific project for Antarctica from the analysis of the Antarctic Treaty System (ATS) geopolitical evolution. The Antarctic question, as discussed in this thesis, is based in two antagonistic theoretical premises taken from the foreign relations (realism and liberalism). The premises of scientific collaboration and the pacific use of the region, established in the Antarctic Treaty (1959), determined a discussion of this topic using a liberal epistemology. The Antarctic geopolitics at the beginning of the 21st century leans towards a scientific-environmental dialectics, to the detriment of the economical-territorial dimension that dominated the discourse for the Austral region up to the emblematic year of 1991, when the Protocol on Environmental Protection to the Antarctic Treaty (Madrid Protocol) was ratified. If the 20th century was marked by the arrival of the Antarctic science, represented by the International Geophysical Year (1957-1958), the current century is characterized, so far, as the one in which the Antarctic science should build its own agenda. The Signatory-States increasingly recognize the political weight of an Antarctic science of excellence within the ATS. By establishing the Brazilian Antarctic Program (PROANTAR, from the Portuguese Programa Antártico Brasileiro) in 1982, Brazil started to defend of its substantial interests in the Antarctic region. These interests, at first, were subordinated to the Cold War contingencies and the Brazil-potency Project. However, the subjective invocation of such interests did not allow the delimitation of its real extent. This geopolitical positioning in relation to Antarctica was first mentioned in 2011 when the Antarctic question, through the preparation of a Strategic Planning for PROANTAR (2012 - 2022), acquired a relative strategic importance for the country. In other words, the program became closer to a project of State. This plan contains directives that shall grant a relevant political status to Brazil within the ATS, which implies the effective participation of the country in the decisions about the fate of the region. The integration of the country into the select group of signatory States that develop cutting-edge research in Antarctica is the main directive of this plan. By understanding the strategic-geopolitical importance of Antarctica to Brazil, and the role of science in the ATS politics, this thesis proposes new challenges and paradigms to the Brazilian Antarctic science, supporting to the current Strategic Planning for PROANTAR (2012 - 2022) and the most recent Action Plan for the Antarctic Science (2013 - 2018). Thus, the analysis of PROANTAR from the perspective of the definition of a strategic-scientific project and its geopolitical repercussions are the main objetives of this thesis, which are reflected in the following goals: an analysis of the Antarctic geopolitics, which determined a preliminary discussion regarding the geopolitical premises of the Treaty and the Antarctic science from a historical perspective; an analysis of the geopolitical dimensions of the region at the benning of the 21st century, identifying the year 1991 (ratification of the Madrid Protocol) as the ATS turning point, when the scientific-environmental dimension began to acquired a greater geopolitical relevance; an analysis of the Antarctic question in the Brazilian geopolitical line of thought, which allowed the discussion about the construction of a possible Antarctic territorial imaginary, as well as its repercussion on the scientific dimension of PROANTAR. Finally, we analyze the new challenges to the Brazilian Antarctic science in the 21st century: the geographic expansion of the PROANTAR research in that continent, especially the investigations into the Antarctic ice sheet, breaking the paradigm of a peripheral science that has been historically confined to the Antarctic Peninsula region; and the institution of a policy that guarantees the quality of the scientific production through an adequate logistic-financial support. Overcoming such challenges is paramount for the inclusion of the Brazilian Antarctic research in the so-called emerging frontiers of science. Nonetheless, as we analyze the political-scientific actions, converging to the definition of a Brazilian strategic project for Antarctic, which has been implemented since the beginning of the century, it becomes clearer the contradictions and obstacles to the definition of such project become: the bureaucratic hindrances and the volatile political actions, which in addition to the lack of recognition of the (geo)political relevance of a cutting-edge Antarctic science, especially by a large part of the scientific community working at PROANTAR, prevent the institution of a the scientific politicy and the definition of a strategic-scientific project for the region.