A metagenomic gene library prepared from soil found beneath a mummified seal carcass in the Miers Valley, Antarctica, suggests an environment rich in uncharacterised biodiversity including enzymes with possible application to industrial processes. A sequence based gene mining investigation was performed on a clone, which archives a metagenomic sequence from this environment. The sequence was annotated using de novo bioinformatics and molecular biology techniques. A predicted NAD+-dependent DNA ligase, ligDB1 was selected for further characterisation. LigDB1 encodes a gene product that contains all the sequence features of a functional ligase. The protein was overexpressed in a heterologous E.coli host and purified to homogeneity. LigDB1 did not exhibit nick sealing activity, but was able to perform AMP-dependent DNA relaxation in the presence of high concentrations of enzyme. DNA modifying enzymes from cold environments perform optimally at low temperatures and may be of use as molecular tools in biotechnology. Complete characterisation of this enzyme is subject to further investigations. / Magister Scientiae - MSc

Pseudozyma (Candida) antarctica lipase B (PalB) was expressed in Escherichia coli facilitating protein engineering. The lack of glycosylation was evaluated for a deeper understanding of the difficulties in expressing PalB in E. coli. Different systems were tested: periplasmic expression in Rosetta (DE3), cytosolic expression in Rosetta-gami 2(DE3), Origami 2(DE3), and coexpression of groES and groEL. Periplasmic expression resulted 5.2 mg/L active PalB at 16 °C in shake flasks. This expression level was improved by using the EnBase technology, enabling fed-batch cultivation in 24-deep well scale. The feed rate was titrated with the addition of α-amylase, which slowly releases glucose as energy source. Different media were evaluated where the EnBase mineral salt medium resulted in 7.0 mg/L of active PalB. Protein secreted directly into the media was obtained using the constitutive glyceraldehyde-3-phosphate dehydrogenase (GAP) promoter for screening and production of PalB in P. pastoris. A protease sensitive fusion protein CBM-PalB (cellulose-binding module) was used as a model system. When optimised, the expression system resulted in 46 mg/L lipase in 72 hours in shake flask, 37 mg/L lipase in 28 hours in 96-deep-well plate format, and 2.9 g PalB per 10 L bioreactor cultivation. The E. coli expression system was used to express a small focused library of PalB variants, designed to prevent water from entering the active site through a hypothesised tunnel. Screening of the library was performed with a developed assay, allowing for simultaneous detection of both transacylation and hydrolytic activity. From the library a mutant S47L, in which the inner part of the tunnel was blocked, was found to catalyse transacylation of vinyl butyrate in 20 mM butanol 14 times faster than hydrolysis. Water tunnels, assisting water in reaching the active sites, were furthermore found by molecular modelling in many hydrolases. Molecular modelling showed a specific water tunnel in PalB. This was supported by experimental data, where the double mutant Q46A S47L catalysed transacylation faster than hydrolysis compared to the wild type PalB. / <p>QC 20100818</p>

The overall purpose of this thesis is to examine problems concerning implementation of the concept of sustainable development in the area of water resources using Thailand as a case study of a developing country. The aims and objectives of the thesis are to provide an analysis of water case studies focusing on fieldwork undertaken in different regions in Thailand, an analysis of the legal system; and strategies for environmental protection; considered in the context of rapid economic expansion. The thesis begins with an examination of the foundation and background of Thailand's legal system, its economic development and its environment. Particular emphasis is given in the thesis to water resources. Water is a specific medium to judge pollution standards as a whole. Pollution for land and air often eventually makes it way into water system. Water regulation and pollution control is an example of environmental regulation as a whole. This is followed by an analysis and evaluation of the legal framework of environmental law. The aim is to examine the evolution of the legal protection of the environment in Thailand as well as to analyse the existing contradictions between the country's legal order and its actual environmental problems. The dynamics of the country's political process are then considered. Finally, the question of how the concept of sustainable development might assist in the application of environmental protection to water resources in Thailand is examined, using disputes over water allocation and water pollution. The case studies are drawn from different regions in Thailand. In Thailand there has certainly been more environmental awareness in recent years, but the implementation of sustainable development strategies remains at an early stage, despite, the Rio conference in 1992 and Rio II in 1997 emphasising the conservation of natural resources. The concept of sustainable development is also incorporated in the new Enhancement and Conservation of National Environmental Quality Act 1992 (the 1992 Act), despite to a limited extent, some principles for sustainable development such as the precautionary principle, the PPP, EIA, right of access to environmental information and public participation. In Thailand primary legislation is in place but water resources regulations are required. Thailand is on a slow learning curve in its strategies for protecting the environment. In the thesis, case studies at a local level have been undertaken and through these case studies, it is clear that sustainable development concept is not fully integrated and accepted as a way to solve water problems at a local level. This indicates a failure of western concepts and their adaptation in developing countries such as Thailand. However, traditional approaches may be used to improve and promote sustainable development concepts together with Agenda 21, western approaches and experiences, which is called "The Mixed Approach". Thailand is in the advantageous position of being able to learn from the mistakes and environmental failures of the developed countries with respect to water resources policy. At the very least, it must acknowledge that environmental problems cannot be fundamentally solved without addressing them at the time of economic development. Still further, Thailand must not adopt the model of western environmental protection laws without first ensuring that the new reforms are suitable for the needs of the Thai economy and people.

This thesis describes and interprets the historical development of the legal regulation of the Ugandan trade union movement and assesses the relative importance of law in the determination of the character of trade union organisation in the post-colonial period 1962-1987. Chapter I defines the scope of the thesis and identifies the theoretical framework and analytical themes on which the thesis is based. Chapter II deals with the colonial foundations of the post-colonial legislation with which the thesis is mainly concerned. Chapters III, IV and V cover the period 1962-1987 whereby we analyse, first, the class and political character of the legal changes that take place between 1963-1976. Secondly, we examine the practical operation and impact of the law vis-a-vis the role of state policy and behaviour, the ideological outlook adopted by the trade unions, union constitutional structures and leadership struggles in the formation of the character of contemporary trade unionism in Uganda. The thesis treats law as a historical category and takes as its starting point the Marxist conceptualisations which view law variously as an instrument of the dominant class, as ideology or which attempt a materialist analysis. From these perspectives we examine the processes of class struggle through which the specific legislation came into being and more crucially the importance of the balance of class forces in the practical utilisation of legal rights or restrictions. We conclude in Chapter VI that while the economic parameters in which trade unions exist and operate are important determinants of union character, within those parameters the character of the state has proved to be most crucial. But at the level of the unions themselves, the ideology they adopt, their constitutional structures and leadership struggles, together, have created the contemporary undemocratic, economistic-apolitical and technocratic aspects of trade unionism in Uganda. However law has been important for the unions to the extent that it has been mainly a source of legitimation for their autonomous existence, most of the time, in their chequered history. The analysis of the historical and class origins and nature of the law regulating trade union organisation and the assessment we make of the role of law vis-a-vis the role played by other factors in determining the character of trade union organisation in Uganda is, in our view, an original contribution to the knowledge of industrial relations law in Uganda. The construction and interpretation of the historical phases through which both trade union law and trade union organisation have passed is likewise an original contribution to the knowledge of trade unionism in Uganda.

Today, the Nigerian oil industry is dominated by MNOCs who provide the technology and managerial expertise for the running of the industry. Petroleum development is a capital-intensive business involving enormous sums of money in foreign exchange. It also involves a lot of negotiations between the MNOCs and Nigeria. These negotiations often end with signing of contractual obligations by both sides. Nigeria, being a Third world country is at obvious disadvantage compared to the MNOCs in terms of risk capital, technology and management skills. The major focus of the study is on the structure and forms of petroleum development contracts between Nigeria and the MNOCs. The scope covers contracts spanning the period when oil exploration first began in Nigeria to the present. Crucial issues such as ownership, control, transfer of technology, financial returns and 'indigenisation' of the industry under the contracts is examined against the background of the country's overall foreign investment policies, petroleum policies and changes in the global oil scene. The aim is to see whether the contracts strike a balance between foreign exploitation and national policy objectives. With contemporary study of law gradually moving towards the study of law as an interdisciplinary subject, the study significantly draws on political economy writings in economics, politics and law. It is found that three kinds of petroleum contracts are operating in Nigeria. These include - concession regimes, joint venture/participation agreements and production sharing/risk service contracts. Also that the structures of these contracts are largely based on the bargaining strength of the two parties. Although, the study argued that Nigeria had improved her bargaining position through her experience over the years and membership of OPEC, yet the study demonstrates that these contracts do not allow Nigeria enough opportunity to reduce her dependence on the MNOCs. In all, the study demonstrates how difficult it is for a less developed country such as Nigeria to gain complete control over its petroleum resource (even if it has the capital) if it lacks technological and managerial capabilities. It also demonstrates the role and limitations of law in fashioning the framework for relations between MNCs and the TWCs.

This research looks at the legal regime governing foreign direct investment (FDI) in Taiwan, and at the interaction between the Government's economic policies, legal reform and FDI in the economic development of Taiwan. The research for this thesis is focused on the period of 1945 to the present; however, a study of the pre-1945 period is provided as a basis for analysing the post-1945 developments. There are three principal aims of this thesis. First, the thesis is designed to illustrate how the economic success of Taiwan challenges traditional views put forward in development theories and in law and development theories, in particular. Secondly, the thesis considers the role of law in the development process. By examining the evolution and operation of the FDI legal regime in Taiwan in its economic, social, political and historical context, this research suggests that the role of law is as a 'doorkeeper' for a country's development. If consistent with a public-interest-oriented economic policy, an appropriate and wellconsidered legal regime can help a country's development without risking its economic sovereignty. Finally, this thesis examines Taiwan's current FDI regime for its appropriateness. Using international law as a reference-point, a detailed analysis is made of Taiwan's current FDI laws. The thesis suggests that certain of these laws are out of date and that further legal reform is required. The thesis concludes by slightly modifying the developmental model for law and FDI which is put forward in Chapter 1, in order to emphasise the important role of government economic policy in Taiwan's development. It is submitted that the Government's choice of development strategy in each of Taiwan's different development phases has been crucial to Taiwan's success. The thesis also concludes that an appropriate legal regime remains important for a country's development regardless of its development status.

Antarctic glacier forfields are extreme environments and pioneer sites for ecological succession. The Antarctic continent shows microbial community development as a natural laboratory because of its special environment, geographic isolation and little anthropogenic influence. Increasing temperatures due to global warming lead to enhanced deglaciation processes in cold-affected habitats and new terrain is becoming exposed to soil formation and accessible for microbial colonisation. This study aims to understand the structure and development of glacier forefield bacterial communities, especially how soil parameters impact the microorganisms and how those are adapted to the extreme conditions of the habitat. To this effect, a combination of cultivation experiments, molecular, geophysical and geochemical analysis was applied to examine two glacier forfields of the Larsemann Hills, East Antarctica. Culture-independent molecular tools such as terminal restriction length polymorphism (T-RFLP), clone libraries and quantitative real-time PCR (qPCR) were used to determine bacterial diversity and distribution. Cultivation of yet unknown species was carried out to get insights in the physiology and adaptation of the microorganisms. Adaptation strategies of the microorganisms were studied by determining changes of the cell membrane phospholipid fatty acid (PLFA) inventory of an isolated bacterium in response to temperature and pH fluctuations and by measuring enzyme activity at low temperature in environmental soil samples. The two studied glacier forefields are extreme habitats characterised by low temperatures, low water availability and small oligotrophic nutrient pools and represent sites of different bacterial succession in relation to soil parameters. The investigated sites showed microbial succession at an early step of soil formation near the ice tongue in comparison to closely located but rather older and more developed soil from the forefield. At the early step the succession is influenced by a deglaciation-dependent areal shift of soil parameters followed by a variable and prevalently depth-related distribution of the soil parameters that is driven by the extreme Antarctic conditions. The dominant taxa in the glacier forefields are Actinobacteria, Acidobacteria, Proteobacteria, Bacteroidetes, Cyanobacteria and Chloroflexi. The connection of soil characteristics with bacterial community structure showed that soil parameter and soil formation along the glacier forefield influence the distribution of certain phyla. In the early step of succession the relative undifferentiated bacterial diversity reflects the undifferentiated soil development and has a high potential to shift according to past and present environmental conditions. With progressing development environmental constraints such as water or carbon limitation have a greater influence. Adapting the culturing conditions to the cold and oligotrophic environment, the number of culturable heterotrophic bacteria reached up to 108 colony forming units per gram soil and 148 isolates were obtained. Two new psychrotolerant bacteria, Herbaspirillum psychrotolerans PB1T and Chryseobacterium frigidisoli PB4T, were characterised in detail and described as novel species in the family of Oxalobacteraceae and Flavobacteriaceae, respectively. The isolates are able to grow at low temperatures tolerating temperature fluctuations and they are not specialised to a certain substrate, therefore they are well-adapted to the cold and oligotrophic environment. The adaptation strategies of the microorganisms were analysed in environmental samples and cultures focussing on extracellular enzyme activity at low temperature and PLFA analyses. Extracellular phosphatases (pH 11 and pH 6.5), β-glucosidase, invertase and urease activity were detected in the glacier forefield soils at low temperature (14°C) catalysing the conversion of various compounds providing necessary substrates and may further play a role in the soil formation and total carbon turnover of the habitat. The PLFA analysis of the newly isolated species C. frigidisoli showed that the cold-adapted strain develops different strategies to maintain the cell membrane function under changing environmental conditions by altering the PLFA inventory at different temperatures and pH values. A newly discovered fatty acid, which was not found in any other microorganism so far, significantly increased at decreasing temperature and low pH and thus plays an important role in the adaption of C. frigidisoli. This work gives insights into the diversity, distribution and adaptation mechanisms of microbial communities in oligotrophic cold-affected soils and shows that Antarctic glacier forefields are suitable model systems to study bacterial colonisation in connection to soil formation. / Gletschervorfelder der Antarktis stellen extreme Habitate dar und sind Pionierstandorte biologischer Sukzession. Insbesondere unter Berücksichtigung zuletzt beobachteter und vorausgesagter Erwärmungstrends in der Antarktis und der Relevanz der Mikroorganismen für das Antarktische Ökosystem, ist es essentiell mehr Informationen über die Entwicklung frisch exponierter Gletschervorfelder zu erlangen. Ziel dieser Studie ist es, die Struktur und Entwicklung bakterieller Gletschervorfeldgemeinschaften zu verstehen, insbesondere wie die Mikroorganismen von den Bodenparametern beeinflusst werden und wie diese sich an die extremen Bedingungen des Habitats anpassen. Für die Untersuchung der Proben von zwei Gletschervorfeldern aus den Larsemann Bergen der Ostantarktis diente eine Kombination aus Kultivierungsexperimenten und molekularen, geophysikalischen und geochemischen Analysen. Die untersuchten Gletschervorfelder sind durch extrem niedrige Temperaturen, einer geringen biologischen Wasserverfügbarkeit und oligotrophe Nährstoffgehalte charakterisiert und zeigen unterschiedliche Entwicklungsstufen in Verbindung zu den Bodenparametern. In einem frühen Schritt der Bodenbildung in der Nähe der Gletscherzunge sind die Gemeinschaften undifferenziert, doch mit fortschreitender Entwicklung nimmt de Einfluss von Wasser- und Nährstofflimitationen zu. Nachdem die Kultivierungsbedingungen den kalten und nährstoffarmen Bedingungen des Habitats angepasst wurden, konnten 108 koloniebildende Einheiten heterotropher Bakterien pro Gramm Boden angereichert und daraus 148 Isolate gewonnen werden. Zwei neue psychrotolerante Bakterien, Herbaspirillum psychrotolerans PB1T und Chryseobacterium frigidisoli PB4T, wurden detailiert charakterisiert und als jeweils neue Spezies beschrieben. Die Anpassungsstrategien der Mikroorganismen an die extremen antarktischen Bedingungen zeigten sich in der Aktivität extrazellulärer Enzyme bei niedriger Temperatur, die mit derer temperierter Habitate vergleichbar ist, und in der Fähigkeit der Mikroorganismen, die Fettsäurezusammensetzung der Zellmembran zu ändern. Eine neue Fettsäure, die bisher in keinen anderen Mikroorganismus gefunden wurde, spielt eine entscheidende Rolle in der Anpassung des neu-beschriebenen Bakteriums C. frigidisoli an niedrige Temperaturen und saure pH-Werte. Diese Arbeit gibt einen Einblick in die Vielfalt, Verteilung und Anpassung mikrobieller Gemeinschaften in nährstoffarmen und Kälte-beeinflussten Habitaten und zeigt, dass Antarktische Gletschervorfelder geeignete Modellsysteme, um bakterielle Besiedelung in Verbindung zu Bodenbildung zu untersuchen.

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.

Contaminated sediments pose a direct risk to sediment fauna and have the potential to affect other benthic assemblages. Disturbances that resuspend and remobilise contaminants may impact on filter-feeding, hard-substrate organisms that live immediately above sediments. This thesis uses laboratory and field manipulations to examine the impact of metal-contaminated sediments on sediment fauna and hard-substrate fauna simultaneously. It also compares the response of assemblages to metal contamination in a temperate and polar ecosystem. Simulated resuspension exposures in the laboratory indicated that contaminated sediments have the potential to affect hard-substrate organisms. Spirorbid polychaetes responded to both aqueous metals and to resuspended, particulate-bound metals. Impacts on hard-substrate fauna were however, not observed in manipulative field experiments using metal-spiked sediments. The recruitment and cover of hard-substrate organisms were either not affected or enhanced above contaminated sediments. In contrast, metal contamination had direct negative effects on sediment fauna, with a reduction in the abundance of most taxa. Results suggest that sediment fauna may interact with hard-substrate fauna through physical and/or biological mechanisms. In a reciprocal transplant experiment, established Antarctic hard-substrate assemblages were also unaffected by contaminant concentrations at an impacted site. Overall, metal-contaminated sediments are unlikely to pose as serious a threat to hard-substrate fauna as they do to sediment fauna. Contaminated sediments are not restricted to industrialised regions, and human activities in Antarctica have resulted in localised contamination near research stations. Although Antarctic assemblages are thought to be more sensitive than temperate assemblages to contaminants, few studies have explicitly examined this. Little evidence was found to support the theory that Antarctic assemblages are more susceptible to contaminated sediments. The response of Antarctic and temperate assemblages in the field to metal-contaminated sediments over a 10-11 month period was comparable. Responses were of a similar magnitude, despite differences in the composition of assemblages. In 10-d toxicity tests, the mortality of a common Antarctic hard-substrate organism was relatively insensitive to aqueous Cu, Zn and Pb. These results suggest that using current sediment quality guidelines from Australia may be a useful screening tool to assess the risk associated with contaminated sediments in Antarctica.

The purpose of this research was to investigate the physical weathering of rock along the Victoria Land Coast, Antarctica. It was designed to contribute to the Latitudinal Gradient Project, a joint initiative between the New Zealand, Italian and United States Antarctic Programmes. The Latitudinal Gradient Project aims to improve our understanding of the ecosystems of the Dry Valleys and ice-free areas of the Ross Sea Region and, by using latitude as a proxy measure, identify how they might be affected by future climate change. The approach taken for this research was to use information on rock (from one rock group) temperature and moisture conditions gathered from three field locations to inform laboratory simulations. The laboratory simulations would then be used to investigate the weathering of small rock blocks and aggregates. Two temperature cycles approximating those experienced during summer and spring/autumn were identified and simulations undertaken in a specially adapted freezer. Three levels of moisture were applied: no moisture, half saturation and full saturation. Results of the laboratory simulations indicated that although rocks responded in different ways to different processes, granular disintegration took place even in the absence of additional moisture and did not require crossings of the 0 OC isotherm, nor were high levels of moisture required for across zero temperature cycling to produce weathering effects. A model that related weathering to latitude was developed and changes in climate explored. It was found that the weathering effect of summer and spring/autumn cycles was different and depended on rock characteristics rather than latitude. Increasing the ratio of summer to spring/autumn temperature cycles by 10% indicated that weathering could decrease or remain the same depending on the particular rock. Changes in temperature were found to be more important than changes in moisture. A weathering index that related local climate and rock properties to weathering was also developed and this highlighted the difficulties of using laboratory results to predict field rates of weathering. There were some surprising results from the field, including the presence of much more moisture on the surface of the rock, primarily from blowing snow, than had been predicted for this dry environment. This occurred even in the presence of negative rock surface temperatures. In addition, winter rock surface temperatures can fluctuate up to 25 OC, getting as warm as -10 OC. Macro-climate and changes in air temperature in response to foehn and katabatic winds were the drivers for these fluctuations.