Submitted by Francine Silva (francine.silva@unipampa.edu.br) on 2016-09-16T14:48:23Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Comunidade vegetais de áreas de degelo da Ilha Half Moon, Arquipélago das Shetlands do Sul, Antártica.pdf: 769779 bytes, checksum: 794a3b4b95c7a64c38ab5708c8c281b2 (MD5) / Made available in DSpace on 2016-09-16T14:48:23Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Comunidade vegetais de áreas de degelo da Ilha Half Moon, Arquipélago das Shetlands do Sul, Antártica.pdf: 769779 bytes, checksum: 794a3b4b95c7a64c38ab5708c8c281b2 (MD5) Previous issue date: 2015-07-28 / Este trabalho apresenta os resultados do estudo das comunidades vegetais de áreas de degelo realizado durante os verões austrais de 2013/2014 e 2014/2015, nos meses de fevereiro e março, na Ilha Half Moon, no Arquipélago Shetlands do Sul, Antártica Marítima, com o objetivo de avaliar a distribuição e abundância de musgos e líquens, bem como para descrever e mapear as comunidades de plantas que ocorrem na área. As plantas foram correlacionadas com a ocorrência de aves marinhas, relevo e umidade para entender sua influência sobre a distribuição de plantas. Para aferir as comunidades existentes na ilha através da fitossociologia e quantificar as espécies com maior significância ecológica (IES) foi utilizada a metodologia de quadrados (20 x 20cm) de Braun-Blanquet adaptado às condições Antárticas. Para o mapeamento da área foi utilizado o DGPS Astech Promark II®, com precisão sub-metrica e posteriormente processados no software Astech Solutions®. Foram identificadas 37 espécies de briófitas, 59 liquens, uma angiosperma, a Deschampsia antarctica Desv., e duas espécies de algas macroscópicas. Foram dispostos 358 quadrados e identificadas cinco comunidades vegetais na ilha, distribuídas de acordo com a ocorrência de animais e a influência marítima. As comunidades descritas foram as seguintes: Comunidade Liquens fruticulosos, Comunidade carpete de musgos, Comunidade de Liquens Muscicolas, Comunidade de Liquens crustosos e Comunidade Turfa de musgos. A espécie que apresentou o IES mais elevado da ilha foi Sanionia uncinata (Hedw.) Loeske aparecendo em 71.78% dos quadrados amostrados. A comunidade que apresentou maior número de espécies foi a Carpete de musgos e a mais diversa foi a comunidade liquens crustosos, que tem sua maior parte localizada na área onde estão as colônias de pingüins. / This paper presents the results of the study of plant communities of free ice areas conducted during the austral summer of 2013/2014 and 2014/2015, in February and March, on Half Moon Island in the South Shetlands Archipelago, Maritime Antarctica, aiming to evaluate the distribution and abundance of mosses and lichens, as well as to describe the plant communities occurring in the area, with mapping of the vegetation communities. To assess existing communities on the island through the phytosociology and quantify the species with the highest ecological significance (IES) was used the methodology square (20 x 20cm) of Braun-Blanquet adapted to Antarctic conditions. . The area was mapped using an Astech Promark II® DGPS, yielding sub-metric precision after post-processing with Astech Solutions® software. The number of species totalized 38 bryophyte species, 59 lichens, only one flowering plant (Deschampsia antarctica Desv.) and two macroscopic terrestrial algae. Five plant communities were identified in the island, distributed accordingly to animal occurrence and to sea influence. The plant communities were described as follows: Fruticose lichens community, Moss-carpet community, Muscicolous Lichens community, Crustose lichens community and Moss turf community. The species with the highest IES of the island was Sanionia uncinata (Hedw.) Loeske appearing in 71.78% of sampled squares. The community with the highest richness species was the Moss Carpet, and the most diverse community was the crustosos lichens, which has mostly located in the area where the penguin colonies.

When light intensities become supersaturating for photosynthesis, phytoplankton must be able to protect the photosynthetic machinery from potential damage by excess energy absorption. One of the most important photoprotective mechanisms involves the nonradiative dissipation of excess light energy by the interconversion of the carotenoid pigments of the so-called xanthophyll cycle. Very little is known about how the xanthophyll cycle of natural communities of phytoplankton responds to high light conditions and the relationship of this photoprotective mechanism to the surrounding physical environment. The purpose of this thesis was to examine the functioning, activation and relationship to the physical environment of the xanthophyll cycle in phytoplankton from the Antarctic ecosystem and the Southern Ocean. Experiments in Antarctica were conducted in austral spring under various natural and artificial light regimes including the use of a newly developed light mixing simulator (LMS). Photoprotective carotenoid pigment concentrations were determined using a carotenoid specific protocol for High Performance Liquid Chromatography (HPLC). The photoprotective xanthophyll cycle was not active in Antarctic sea ice algae under the low light conditions under the annual sea ice. When sea ice algae are exposed to high irradiance, there was an initial rapid deepoxidation of the xanthophyll pigment diadinoxanthin (DD) to diatoxanthin (DT). With on-going irradiance exposure, slower deepoxidation of DD continued. The recovery of DD in the dark or under low light was found to be significantly faster than in temperate algal communities, and is likely a particular adaptation to the unique light environment in Antarctica. The temporal accumulation of pigments of the violaxanthin (VX) xanthophyll cycle was observed for the first time in a natural phytoplankton population. It is hypothesized that the VX cycle may function as a pathway to maintain the pool of DD cycle pigments rather than as a separate photoprotective pathway as observed in higher plants. The high irradiances of ultraviolet - B (290 - 320 nm) radiation (UVB) as a result of stratospheric ozone depletion over Antarctica in spring was found to significantly impact on the DD cycle. Exposure to high levels of both ultraviolet-A (320- 400 nm) radiation (UVA) and UVB reduced the photoprotective xanthophyll pigment pool with the greatest reduction occurring after exposure to high levels of UVB. The reduction in the amount of cellular DD after exposure to high levels of UVB was greater than can be explained by deepoxidation activity, which implies that high UVB exposure can lead to a loss of DD from the community. The first-order kinetic rates of the DD cycle were found to be similar to other studies and did not vary with light intensity. Simulations under natural light using the LMS demonstrated that the response of the DD cycle to static in situ incubations and when subject to vertical mixing was not similar, and that static incubations overestimate DD-cycle activity Over the long term, algae in a simulated vertically mixed environment were able to increase the pool of xanthophyll pigments compared to static conditions where the pool remained the same or decreased. Oceanographic observations from the subantarctic waters south-east of New Zealand in austral autumn provided the physical background for new insights into the xanthophyll cycle of Southern Ocean phytoplankton. The circulation flow and water masses between the Bounty Plateau and Bollons Seamount was resolved and shown to differ from numerical models. Relatively little of the warm and salty Subantarctic Mode Water (SAMW) from the Tasman Sea is carried in the flow of the Subantarctic Front (SAF). The spatial distribution of photoprotective xanthophyll pigments showed higher than expected concentrations in the surface mixed layer of the region. The high concentration of photoprotective pigments is considered to be a consequence of the low iron concentrations in southern waters and the highly variable light and vertical mixing environment. The high cellular concentrations of photoprotective pigments constrains photosynthetic activity implying that the photoprotective pigments may play a more significant role in controlling phytoplankton production in the Southern Ocean than previously thought. Analysis of the xanthophyll pigments and physical oceanography with a Self-Organising map (SOM) Artificial Neural Network (ANN) showed that the photophysiological index DT/ (DD+DT) can be used to resolve a change in water type properties. A simple numerical model was developed which can be used to provide a quantitative index of the relative magnitudes of vertical mixing and phytoplankton photoprotection in the water column. This approach may be useful to identify the effects of physical changes in the surface mixed layer of the Southern Ocean as predicted by climate change modelling.

vii, 235 leaves : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (M.D. 1974) from the Dept. of Psychiatry, University of Adelaide

Understanding the Earth's climate system and particularly climate variability presents one of the most difficult and urgent challenges in science. The Antarctic plays a crucial role in the global climate system, since it is the principal region of radiative energy deficit and atmospheric cooling. An assessment of regional climate model HIRHAM is presented. The simulations are generated with the HIRHAM model, which is modified for Antarctic applications. With a horizontal resolution of 55km, the model has been run for the period 1958-1998 creating long-term simulations from initial and boundary conditions provided by the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA40 re-analysis. The model output is compared with observations from observation stations, upper air data, global atmospheric analyses and satellite data. In comparison with the observations, the evaluation shows that the simulations with the HIRHAM model capture both the large and regional scale circulation features with generally small bias in the modeled variables. On the annual time scale the largest errors in the model simulations are the overestimation total cloud cover and the colder near-surface temperature over the interior of the Antarctic plateau. The low-level temperature inversion as well as low-level wind jet is well captured by the model. The decadal scale processes were studied based on trend calculations. The long-term run was divided into two 20 years parts. The 2m temperature, 500 hPa temperature, MSLP, precipitation and net mass balance trends were calculated for both periods and over 1958 - 1998. During the last two decades the strong surface cooling was observed over the Eastern Antarctica, this result is in good agreement with the result of Chapman and Walsh (2005) who calculated the temperature trend based on the observational data. The MSLP trend reveals a big disparity between the first and second parts of the 40 year run. The overall trend shows the strengthening of the circumpolar vortex and continental anticyclone. The net mass balance as well as precipitation show a positive trend over the Antarctic Peninsula region, along Wilkes Land and in Dronning Maud Land. The Antarctic ice sheet grows over the Eastern part of Antarctica with small exceptions in Dronning Maud Land and Wilkes Land and sinks in the Antarctic Peninsula; this result is in good agreement with the satellite-measured altitude presented in Davis (2005) . To better understand the horizontal structure of MSLP, temperature and net mass balance trends the influence of the Southern Annual Mode (SAM) on the Antarctic climate was investigated. The main meteorological parameters during the positive and negative Antarctic Oscillation (AAO) phases were compared to each other. A positive/negative AAO index means strengthening/weakening of the circumpolar vortex, poleward/northward storm tracks and prevailing/weakening westerly winds. For detailed investigation of global teleconnection, two positive and one negative periods of AAO phase were chosen. The differences in MSLP and 2m temperature between positive and negative AAO years during the winter months partly explain the surface cooling during the last decades. / Eine der dringendsten wissenschaftlichen Herausforderungen besteht darin, das Klimasystem der Erde und die Prozesse zu verstehen, die seine Klimavariabilität bestimmen. Die Antarktis spielt eine entscheidende Rolle im globalen Klimasystem, da sie die wesentliche Energiesenke und atmosphärische Abkühlregion darstellt. In dieser Arbeit wird das regionale Klimamodell HIRHAM zur Untersuchung des Klimas der Antarktis eingesetzt, das dafür speziell angepasst wurde. Mit einer horizontalen Auflösung von 50 km und 25 vertikalen Schichten wurden Simulationen für 40 Jahre von 1958-1998 durchgeführt, wobei die Anfangs- und Randbedingungen durch die ERA40 Daten des ECMWF (European Centre for Medium-Range Weather Forecasts) geliefert wurden. Die Modellergebnisse wurden mit Daten von Beobachtungsstationen, aerologischen Vertikalsondierungen, globalen Analysedaten und Satellitendaten verglichen. Diese Validierung zeigt, dass die HIRHAM Modellsimulationen die globalen und regionalen Zirkulationsmuster mit einem vertretbaren Modellfehler generieren. Auf der jährlichen Zeitskale zeigen sich die größten Modellfehler in einer Überbestimmung der totalen Wolkenbedeckung und der kalten bodennahen Temperaturen der Atmosphäre. Die bodennahen Inversionen und katabatischen Windsysteme werden durch das Modell gut wiedergegeben. Dekadische Prozesse wurden durch Trendberechnungen analysiert. Dazu wurden die 40 Jahre umfassenden Simulationen in zwei 20 Jahre Abschnitte von 1958-1978 und 1979-1998 unterteilt. Die Trends in den 2m Temperaturen, im mittleren Bodenluftdruck, 500 hPa Geopotential, Niederschlag und der Netto Massenbilanz wurden berechnet. In den letzten zwei Dekaden wurde eine starke atmosphärische Abkühlung an der Oberfläche in der Ostantarktis simuliert, die in guter Übereinstimmung mit den Trendanalysen aus Beobachtungen von Chapman und Walsh (2005) steht. Der Trend im mittleren Bodenluftdruck weist deutliche Unterschiede zwischen den ersten Periode 1958-1978 und der zweiten Periode 1979-1998 auf. Insgesamt verstärkt sich über die untersuchten 40 Jahre der zirkumpolare Tiefdruckwirbel und die kontinentale Antizyklone. Die Nettomassenbilanz und der Niederschlag zeigen einen positiven Trend über der Antarktischen Halbinsel, Wilkes Land und Dronning Maud Land. Das antarktische Eisschild wächst im östlichen Teil der Antarktis mit geringen Ausnahmen in Dronning Maud Land und Wilkes Land an und schächt sich über der antarktischen Halbinsel ab. Dieses Resultat befindet sich in Übereinstimmung mit den Akkumulationstrends von Davis (2005) auf der Basis von Satellitendaten. Die horizontalen Strukturen der simulierten antarktischen Trends im mittleren Bodenluftdruck, in der 2m Temperatur und der Netto Massenbilanz wurden mit Trends des globalen Telekonnektionsmusters der Südhemisphäre verglichen. Dazu wurden wesentliche atmosphärische Parameter für positive und negative Phasen der Antarktischen Oszillation (AAO) analysiert. Die positiven/negativen AAO Phasen gehen einher mit einer Verstärkung/Abschwächung des zirkumpolaren Tiefdruckwirbels, verstärkten/reduzierten Stormtracks und verstärkten/abgeschwächten Westwinden. Für eine tiefergehende Untersuchung wurden zwei positive und eine negative AAO Phase miteinander verglichen. Die Unterschiede im Bodenluftdruck und der 2m Temperatur zwischen den positiven und negativen AAO Perioden können den Abkühlungstrend während der letzten Dekaden zu großen Teilen erklären.

<p>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.</p>

Polybrominated diphenyl ethers (PBDEs) are anthropogenic chemicals whose environmental behavior is similar to the well-known polychlorinated biphenyls (PCBs). Few studies have quantified the amount and distribution of PBDEs in the southern hemisphere and Antarctica. The analyses reported in this dissertation document the levels of PBDEs in lichens, mosses and seabird eggs collected at King George Island, Antarctic Peninsula. The analyses were carried out using Gas Chromatography/Electron Impact-Mass Spectrometry (GC/EI-MS). Employing the ion stacking technique lowered detection limits and ensured instrument selectivity and sensitivity to the compounds of interest. Lichens and mosses absorb PBDEs directly from the atmosphere and their contamination indicates that long-range transport is the primary source of these chemicals to King George Island. The congener patterns of PBDEs in plants indicate that commercial mixtures of Penta-BDE and Octa-BDE have reached Antarctica. Differences in the levels of PBDEs observed in lichens and mosses are probably due to factors that govern the uptake of PBDEs from the atmosphere. Contamination in lichens showed a positive correlation with local precipitation. Conversely, absorption of PBDEs in mosses appears to be controlled by other plant-specific factors. Marine phytoplankton-derived aerosols are hypothesized to play an important role in the atmospheric transport of PBDEs to the Antarctic environment. PBDEs in south polar skua eggs revealed much higher concentration than in penguin eggs. This is likely associated with the northward migration of these seabirds during the non-breeding season. While penguins reside year-round in Antarctica, south polar skuas migrate northward and can be seen in boreal oceans during the austral winter. Distribution of PBDEs in penguin eggs matches the pattern found in local vegetation suggesting a common source for the chemicals. In contrast, the congener pattern of south polar skuas suggests that birds breeding at King George Island are wintering in the northwestern Pacific Ocean. A potential metabolism of PBDEs in penguin eggs during the incubation period seems to be limited. Most congeners were unaltered from source material in the eggs of chinstrap and gentoo penguins. Low levels of PBDEs, short incubation periods and energy constraints may explain these observations.

Thesis (Ph. D.)--Open University. BLDSC no. DX209779. / 2 volumes.

The fishery for Antarctic krill (Euphausia superba) has received considerable attention in recent years, owing largely to the possibility of its significant expansion and the ecological implications of increased extraction of a keystone species. This thesis employed Ecological Footprint (EF) analysis and life cycle assessment (LCA) to measure the resource use, energy use, and emissions associated with three krill-derived products: meal and oil for aquaculture feeds, and omega-3 krill oil capsules for the nutraceutical market. The product supply chains of one krill fishing and processing company, Aker BioMarine, were used as a case study to examine Antarctic krill-derived products. Antarctic krill products were compared to products from similar fisheries targeting other species for reduction into meal and oil, including Peruvian anchovy (Engraulis ringens), Atlantic herring (Clupea harengus), blue whiting (Micromesistius poutassou) and Gulf menhaden (Brevoortia patronus), on the basis of marine footprint, carbon footprint, and fuel use intensity.

<p>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.</p>

This project examines representations of Antarctica in the theatre and analyses these in terms of space and place in order to chart the development of awareness of the continent. As examples of cultural production, plays and their treatment of imagined Antarctic space can provide insights into how attitudes towards the continent have developed and been expressed by revealing the dominant narratives at various points in time. A close reading of nine plays from 1930 – 2011 focuses on the use of mimetic and diegetic space within the theatre, examining the language used, stories told and attitudes present. Such analysis reveals the factors determining the choice of an Antarctic setting, be they ecological, political or metaphorical, whilst shedding light on how attitudes towards place, space and representation have changed within the theatre context. These plays can be grouped under four thematic headings, namely “In Scott’s Footsteps,” “Retelling,” “Reimagining,” and “Returning.” While Antarctica remains a backdrop in earlier plays, where Heroic Era narratives are foregrounded, more recent productions have seen the continent come to the fore, where it is treated as part of a global web of connections. These plays illustrate a progression in how Antarctica has been represented upon the stage, a progression that parallels how we have thought about Antarctica in general.