The objective of this research is to determine the influence of liquid water content on the toxicity of petroleum hydrocarbons (PHC) to soil microorganisms in frozen soil. This research was conducted on soil collected from an aged diesel fuel spill site at Casey Station, East Antarctica, as well as on spiked diesel contaminated soil from Macquarie Island, a sub-Antarctic island.<p> Suitable soil biogeochemical toxicity endpoints for PHC contamination were identified using sub-Antarctic soil from Macquarie Island spiked with diesel fuel. The sensitivity of nitrification, denitrification, carbohydrate utilization and total soil respiration to diesel fuel was assessed. Potential nitrification activity (PNA) was the most sensitive indicator of contamination assessed for nitrogen cycling, with a PHC concentration effecting microbial activity by 20% of the control response, EC₂₀, of 190 mg PHC kg^-1 soil.<p> Petroleum hydrocarbon toxicity in polar soil was assessed by sampling 32 locations at an aged diesel spill site at Casey Station, East Antarctica. Samples were taken nine times throughout an austral summer to encompass frozen, thaw and refreeze periods. Toxicity was assessed using potential activities of substrate induced respiration, total respiration, nitrification, denitrification, and metabolic quotient, as well as microbial community composition and bacterial biomass. The most sensitive indicator was community composition with an EC₂₅ of 800 mg kg^-1, followed by nitrification (2000 mg kg^-1), microbial biomass (2400 mg kg^-1) and soil respiration (3500 mg kg^-1). Despite changes in potential microbial activities and composition over the frozen/thaw/refreeze period, the sensitivity of these endpoints to PHC did not change with liquid water or temperature. <p> The influence of liquid water (è_liquid) on nutrient supply rate and gas diffusion, which are important factors in microbial degradation of PHC, was determined using contaminated soil from Casey Station. Freezing reduced nutrient supply rate of both NH₄⁺ and NO₃^-. However, an increase in è_liquid was linked to increases in nitrate and ammonia nutrient supply rates in frozen soil. Similarly for gas diffusion, decreases in D_s due to freezing were much more pronounced in soils with low è_liquid compared to soils with higher è_liquid contents. Further research is needed to determine whether bioremediation in cold regions could be enhanced during the period of time where the soil temperature is below 0^oC by controlling factors that increase the amount of liquid water.<p> The influence of liquid water content on the <i>in situ</i> toxicity of PHC to soil microorganisms was evaluated using stable isotope dilution technique to measure gross mineralization and nitrification, which was compared to the toxicity endpoints of potential microbial activities. Liquid water content did not have a significant effect on either gross mineralization or nitrification. Gross nitrification was sensitive to PHC contamination, with toxicity decreasing over time. The EC₂₅ value for gross nitrification was 400 mg kg^-1 for 1 month incubation period. In contrast, gross N mineralization was not sensitive to PHC contamination. Toxic response of gross nitrification to PHC contamination was comparable to PNA with similar EC₂₅ values determined by both measurement endpoints (400 mg kg^-1 for <i>in situ</i> nitrification compared to 200 mg kg^-1 for PNA), indicating that potential microbial activity assays are good surrogates for <i>in situ</i> toxicity of PHC contamination in Polar Regions.<p> Based on ecotoxicological data collected, the recommended soil quality guideline for on PHC contamination in polar soils would be 200 mg kg^-1.

Thesis (Ph. D.) -- Lincoln University, 2010. / Also available via the World Wide Web.

The cold, lightless, and high pressure aquatic environment at the base of the East Antarctic Ice Sheet is of interest to a wide range of disciplines. Stable subglacial lakes and their connecting channels remain perennially liquid three kilometers below some of the coldest places on Earth. The presence of subglacial water impacts flow of the overlying ice and provides clues to the geologic properties of the bedrock below, and may harbor unique life forms which have evolved out of contact with the atmosphere for millions of years. Periodic release of water from this system may impact ocean circulation at the margins of the ice sheet. This research uses airborne radar sounding, with its unique ability to infer properties within and at the base of the ice sheet over large spatial scales, to locate and characterize this unique environment. Subglacial lakes, the primary storage mechanism for subglacial water, have been located and classified into four categories on the basis of the radar reflection properties from the sub-ice interface: Definite lakes are brighter than their surroundings by at least two decibels (relatively bright), and are both consistently reflective (specular) and have a reflection coefficient greater than --10 decibels (absolutely bright). Dim lakes are relatively bright and specular but not absolutely bright, possibly indicating non-steady dynamics in the overlying ice. Fuzzy lakes are both relatively and absolutely bright, but not specular, and may indicate saturated sediments or high frequency spatially heterogeneous distributions of sediment and liquid water (i.e. a braided steam). Indistinct lakes are absolutely bright and specular but no brighter than their surroundings. Lakes themselves and the different classes of lakes are not arranged randomly throughout Antarctica but are clustered around ice divides, ice stream onsets and prominent bedrock troughs, with each cluster demonstrating a different characteristic lake classification distribution. In the bedrock trough of Adventure Subglacial Trench, analysis of satellite altimetry is combined with radar sounding data to calculate a mass budget and infer a flow mechanism for a two cubic kilometer discharge reported to have traveled between two lakes in the region from 1996 -1998. The volume released from the source lake exceeded the volume received by the destination lakes by one and a tenth cubic kilometers, indicating that some water must have escaped downstream from the lowest destination lake over the course of the event. Release of water from the source lake preceded arrival of the water at the destination lakes, 260 kilometers away, by about three months. Water continued draining from the destination lakes for several years after surface subsidence at the source lake had ceased. By 2003, a total of one and a half cubic km or nearly 75% of the water released by the source lake had traveled downstream from the destination lakes. Hydraulic modeling work indicates that the initial release of water from the source lake could have been accommodated by a self-enlarging semicircular channel. Subsequent evolution of the discharge and the three-month delay between release of water from the source lake and arrival of that water at the destination lakes indicates that a shallower and broader distributed water system is responsible for the transport of subglacial water in this region. Such a system would be more stable for the given icebedrock geometry and may explain the observations of intermittent flat bright bedrock reflections in radar data acquired upstream from the destination lake in 2000. For the purpose of better understanding the long-term water budget of the Dome C region, an area upstream of Adventure Trench, eleven dated isochronal internal layers within the ice penetrating radar data were tracked. An age-depth relationship, derived from the European ice core through Dome C is used to calculate strain, estimate melt, model ice temperature, and determine absolute basal reflectivity for the entire region which covers over 28,000 square kilometers. The two largest subglacial lakes within the survey, Concordia and Vincennes, are both associated with enhanced basal melting on their upstream shores at rates locally greater than two millimeters per year. Widely distributed melt rates in the major topographic valleys upstream of these lakes are generally less than one millimeter per year throughout the region with slightly higher melts in the basin draining into Vincennes Subglacial Lake. Although published estimates for geothermal flux are capable of explaining the behavior of ice and water in most of the area, an additional source of basal heat is required to explain melt anomalies and subglacial lakes along the Concordia Ridge. Lake Concordia is expected to discharge water on a similar scale and duration as that observed in Adventure Trench, with a repeat cycle of a few hundred years. / text

The Mesoproterozoic Ritscherflya Supergroup forms an extensive volcano-sedimentary cover succession on the Archaean Grunehogna Province of western Dromring Maud Land, Antarctica. The oldest:, predominantly sedimentary deposits of this cover succession are exposed across the Borgmassivet and southern Ahlmannryggen mountain ranges, and are collectively assigned to the Ahlmannryggen Group. A revised lithostratigraphy places exposures from these two regions in separate subdivisions, with three formations being recognised in the Ahlmannryggen (Pyramiden, Schumacherfjellet and Grunehogna Formations) and four formations being defined for the Borgmassivet (Veten, Framryggen, HogfOlma and Brapiggen Formations). Deposition of these successions occurred in a combination of fluvial braid-plain and braid-delta plain environments, with exposures in the Ahlmannryggen and Borgmassivet regions representing contemporaneous sedimentation in different portions of the same basin, under similar conditions. The development of the Ahlmannryggen Group basin is attributed to flexing associated with continental collision during the assembly of Rodinia. Collision and accretion of a continental island arc terrain (the Maudheim Province) along the southern margin of the Grunehogna Province is considered responsible for flexural snbsidence and the development of a peripheral foreland basin. The Ahlmannryggen Group represents 'molasse' stage infilling of this basin, with sedimentation being dominated by a combination of transverse and longitudinal drainage systems entering a depo-centre located to the east/southeast of the presently exposed succession. SAMANTIIA PERRlTT Detritus entering the basin was sourced either directly or indirectly from at least seven different terrains, aged ca. 1135Ma, ca. 1335Ma, ca. 1600-1700Ma, ca. 2000-2100, ca. 2645Ma, ca. 2400-2900Ma and ca 2900-3300Ma, according to UlPb detrital zircon SHRIMP analysis. The source terrains included the Maudheim Province, basement granites of the Grunehogna Province, an older sedimentary terrain dominated by a banded ironstone association, at least two further magmatic provinces and two metamorphic terrains. Of these source terrains, only the Maudheim Province and Grunehogna Province basement granites are presently exposed in western Dromring Maud Land The subsequent development of large-scale buckle folds and extensive brittle deformation within the Grunehogna Province cover rocks is attributed to the formation of a regionally extensive sinistral strike-slip system during NNW-SSE Pan-African compression, and can be correlated to structures exposed in the Maudheim Province and northern Mozambique. It is proposed that this strike-slip system developed in response to escape tectonics operating during a late stage of Gondwana amalgamation, as a result of the Ross Orogeny, and the suturing of East and West Antarctica / Thesis (Ph.D.)-University of Natal, Durban, 2001.

The oldest rocks of western H.U. Sverdrupfjella, the Jutulrora Formation, consist of interlayered mafic to felsic ortho- and paragneisses thought to represent calc-alkaline volcanic and clastic sedimentary rocks. These rocks are structurally overlain by the largely paragneissic, carbonate- dominated Fuglefjellet Formation which may represent a miogeosynclinal shelf facies. This sequence is structurally overlain by the dominantly para-gneissic Sveabreen Formation which may comprise a eugeosynclinal facies. Three granitic bodies, the Roerkulten, Jutulrora and Brekkerista Granites intrude the Jutulrora Formation. The trace element chemistry of these granites suggest that accessory minerals played significant roles during their generation and crystallization. Various mafic intrusions, now discordant amphibolites, and a phase of diorite veining are present. The Dalmatian Granite was emplaced syntectonically with the 470Ma Pan-African (or Ross) orogeny during D3. This granite was generated by crustal anatexis at >5kb. Jurassic age intrusions include alkaline complexes at Straumsvola and Tvora and numerous dolerite dykes, some of which postdate the alkali intrusions. Five episodes of deformation are recognised. The first two resulted in folds (F1 and F2) which are co-planar and coaxial resulting in type 3 interference structures. Low angle thrust faulting occurred during D2. Fold vergence and associated lineations suggest tectonic transport from the southeast during D1 and D2, D3 involved folding and reverse faulting. The orientations of the fault and axial planes of these structures suggest transport from the west and north-west. D4 involved open dome and basin folding. D6 involved normal faulting and jointing, adjacent and parallel to the Jutulstraumen Glacier in the west. The joints affect the Tvora Alkaline Complex. Three phases of metamorphism, related to the deformation, are recognised. The dominant mineral assemblages are typical of medium to high grade metamorphism and define S1 and S2 planar fabrics. Discordant mafic intrusions provide evidence of a long history of metamorphism. M3 mineral development, commonly represented by biotite, is oriented axial planar to D3 folds. Comparison of the geology of the area with that of southern Mozambique reveals many similarities. These support reconstructions based on geophysical data which juxtapose Dronning Maud Land and southern Africa prior to the break up of Gondwanaland. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1992.

This thesis documents a series of studies performed on the lower atmosphere over the region of the Ross Ice Shelf, Antarctica, and its surroundings. In particular, much of the thesis focuses on the area in the vicinity of Ross Island, a mountainous protrusion in the far north-west of the permanent floating ice shelf. Weather in both the smaller and larger regions is naturally complex and generated by a range of localised and larger scale interactions. In order to better understand the meteorology of the Ross Ice Shelf, including Ross Island, we produce a synoptic climatology of the region based on surface wind output provided by the ERA Interim reanalysis. Output is taken from 1979 to 2011 and thus represents a much longer time scale than covered by previous studies of Ross Ice Shelf winds. The climatology is generated through a clustering routine based on the widely-used $k$-means technique. The results of the routine are discussed and we find that the reanalysis is capable of representing the previously reported features of the region. Cluster composites are also shown to be coherent between reanalysis output and data collected by in situ monitoring devices. We confirm that the Ross Ice Shelf Air Stream (RAS), a jet of fast-moving air that propagates from the Siple Coast across the ice shelf, is a robust feature of the climatology of the region and we find that it has a large impact on the surface temperature. The analysis is continued with reference to two widely studied modes of internal variability, the Southern Annular Mode (SAM) and El Nino-Southern Oscillation (ENSO), which are known to affect local conditions in the Ross Sea region via modulation of the Amundsen-Bellingshausen Sea low. Reanalysis output and results from the clustering routine allow us to examine the impacts of these modes upon the Ross Ice Shelf and Ross Sea in unprecedented detail. Further, we are able to tie changes in the mean pattern to variability within and between particular clusters, allowing us to ascertain the dominant synoptic patterns in forcing the mean variability. The impact on surface temperatures for both modes is found to be high and significant, which we explain with reference to changes in circulation patterns. We further use the results of the clustering algorithm to explore the climatology of the region surrounding Ross Island. By producing composites of local in situ records based on the clustering technique described previously, we are able to generate a climatology of the region that is not hampered by gaps in the observational record. We find that the climate of Ross Island is sensitive to RAS events, due to the ability of strong flows to dramatically increase the temperature. At Scott Base, on the southern tip of the Hut Point Peninsula, the temperature is found to be particularly sensitive to these events. McMurdo Station, which is located less than 3 km away, is observed to be much less sensitive, due to the modulation of synoptic flows by localised topographic influences. Particularly salient is the difference in temperature trends between these two locations, which we show to be statistically significant in the annual and seasonal means from 1979 onwards. By applying a novel temperature reconstruction technique based on the output of the clustering routine, we are able to assess the contribution of changes in circulation to temperature trends at these two locations. We conclude that a large amount of the change in temperature at Scott Base can be explained through circulatory variability over the Ross Ice Shelf. However, the trend at McMurdo Station can not be explained using this technique and may be the result of extremely localised forcing. Data availability in Antarctica is widely known to be low, due to the relative sparsity of observations and ongoing problems with data collection due to extremely inhospitable conditions and challenging logistical considerations. The lack of data at the mesoscale has hampered the understanding of localised processes in the Antarctic atmosphere that may be important for forecasting. Through the development and deployment of a distributed system of atmospheric sensors called

The polar landscapes have, for a long time, held the imaginations of people around the world. These extreme and remote environments have shaped the hearts and minds not only of people who have lived there, but also those who have only heard stories and seen pictures of these far off lands of ice and sky and snow. This dissertation examines the sense of place developed by New Zealanders towards Antarctica, across a spectrum of experiences with the continent, from seasonal workers and scientists, to people who have only ever seen it in books or advertisements. Taking a mainly phenomenological approach, the main objective of the research is to generate a theoretical base on what sense of place is made with and how it is created in extreme and remote environments like Antarctica. After examining 30 questionnaires and 54 interviews, the data indicate that there is no one New Zealand sense of Antarctica; rather, they are as manifold and complex as the individuals consulted. Regardless of the many differences across the various groups, a common thread was found of Antarctica as a place of hope. A hope based on scientific discovery and collaboration, on resource potential and conserving wild spaces. Findings also helped to develop a theoretical model, which builds on the existing works of Tuan (1977), Sack (1997), and Gustafson (2001). Three important theoretical aspects were identified through the analysis, including the ideas of personal connection, narrative emplotement, and one’s sense of identity. The theory contributes to the ongoing discussion of how people encounter and make sense of extreme and remote environments. Both the findings themselves and the theory behind them suggest that policy makers, communicators, and tourism operators be aware of their target audience, their cultural values and changing symbolism, in order to better communicate their intended message.

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.

No description available.

Graduation date: 1986