The 1991 Protocol on Environmental Protection to the Antarctic Treaty requires parties: 'to identify within a systematic environmental-geographical framework ... areas of outstanding aesthetic and wilderness value' (Annex V, article 3.2). In order to develop these frameworks, procedures and techniques used in environmental planning are considered for their applicability and practicality in the severe Antarctic environment. The phrase in the Protocol is taken as two separate topics. Concepts of wilderness are examined first, and it is concluded that the whole continent should be seen as wilderness, with this designation being modified only for those areas in which human influence is visible. In order to understand 'aesthetic values', interpretations given to landscape are considered, before examining the techniques developed in the United Kingdom for landscape assessment, and those used in the United States which are termed visual resource management. Procedures, primarily based on the most recent practice in the United Kingdom, are developed, before testing by fieldwork on the Peninsula. Landscape assessment is seen as a widescale planning procedure, distinct from, though essential to, the site-specific techniques required for environmental impact assessment (EIA). Objective description and classification of the landscape forms the basis of the methodology, with subjective aspects following in the form of clearly stated criteria so as to identify 'areas of outstanding value'. During evaluation comparisons may only be made on a 'like with like' basis, eg glaciers with glaciers, islands with islands. If desired, areas may then be designated under the procedures given in the Protocol.

[From Introduction, p. 2] The first chapter of this thesis deals with an analysis of F2 critical frequency data first for SANAE and then for eleven other Antarctic and sub-Antarctic stations covering the period 1957 to 1969. This shows certain aspects of the F2 behaviour. Some of the results of this chapter have been reported in a paper by Gledhill and Williams. The two most important mechanisms thought to be responsible for the Antarctic f₀F2 behaviour are incoming corpuscular radiation and horizontal neutral winds. These two mechanisms together with two others (the temperature theory of Torr and Torr and the semi-annual variation of neutral atmospheric density) are discussed in detail in part 2 (Chapters 2 to 4) with a view to discovering which aspects of the f₀F2 behaviour over Antarctica can be explained by each theory. An attempt is made in Part 3 (Chapters 5 and 6) to explain the observed behaviour by solving the continuity equation of the ionosphere for high-latitude stations. Finally, besides the critical frequency, another parameter of importance in explaining the behaviour in the F2 region is the height at which the F2 maximum occurs. This quantity cannot be read directly from an ionogram and it is not an easy quantity to determine. In fact the way in which it is usually obtained is by "scaling" the ionogram in question and converting the virtual heights obtained into real heights. In Part 4 (Chapter 7 and 8) an outline is given of the two computer programs which were written to perform this conversion.

Bibliography: leaves 117-130 / xii, 130 leaves : ill. (some col.) ; 30 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, 1989

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: The Southern Ocean (SO) is of significant interest in the understanding of the global carbon cycle and therefore many studies have been conducted to determine the limiting factors controlling the biological pump within the region. During photosynthesis phytoplankton require various nutrients such as NO3, PO4, inorganic carbon and the micronutrient Fe. The SO is a High-Nutrient Low-Chlorophyll region, therefore no macronutrient limitation is experienced by resident phytoplankton but instead the micronutrient Fe is a significant limiting factor within these waters due to limited inputs. Due to deep mixed layer depths, ice cover, low sun angles and cloud cover throughout parts of the year, light is also considered a limiting factor in the SO. Fe and light limitation cause a decrease in photosynthetic efficiency and therefore a decrease in carbon fixation capabilities. During this study we conducted five bioassay shipboard incubation experiments during two cruises along the Greenwich meridian between South Africa and the ice edge, SOSCEx during March and SAFePool during January to February, in which we varied Fe concentrations and light levels to determine the effects of Fe and light limitation or co-limitation within resident phytoplankton. Spatial and temporal variations in phytoplankton response were studied to determine varying effects of limitation across water masses and different stages of bloom decline within the study area. The combined addition of Fe and light gave the largest increase in biomass, photosynthetic capacity and nutrient uptake. In support of the hypotheses tested changes in the photosynthetic apparatus led to changes in the photosynthetic efficiency and growth of the SO phytoplankton, as a result of variations in Fe and light availability. Variability was also observed in the response of phytoplankton to Fe and light amendments due to spatial and temporal variation in resident phytoplankton communities. It was therefore concluded that both Fe and light are significant controls in the resident phytoplankton photosynthetic apparatus, photosynthetic capabilities, organic carbon fixation and therefore the biogeochemical cycles within the Atlantic sector of the SO. / AFRIKAANSE OPSOMMING: Die Suidelike Oseaan (SO) is van beduidende belang in die begrip van die globale koolstofsiklus en dus is baie studies gedoen om die beperkende faktore te bepaal wat die biologiese pomp in die streek beheer. Tydens fotosintese benodig fitoplankton verskillende voedingstowwe soos NO3, PO4, anorganiese koolstof en die mikrovoedingstof Fe. Die SO is 'n High-Nutrient Lae-Chlorofil streek, dus word geen makrovoedingstof beperking ervaar deur inwoner fitoplankton maar in plaas daarvan is die mikrovoedingstof Fe 'n beduidende beperkende faktor binne hierdie waters weens beperkte insette. As gevolg van diep gemengde laag dieptes, ysbedekking, lae son hoeke en wolkbedekking deur dele van die jaar, word lig ook beskou as 'n beperkende faktor in die SO. Fe en lig beperking veroorsaak 'n afname in die fotosintetiese doeltreffendheid en dus 'n afname in koolstof binding vermoëns. Tydens hierdie studie het ons vyf biotoets inkubasie eksperimente aan boord die skeep gedoen tydens twee vaarte langs die Greenwich meridiaan tussen Suid-Afrika en die ys rand, SOSCEx gedurende Maart en SAFePool gedurende Januarie tot Februarie, waarin ons Fe konsentrasies en lig vlakke gewissel het om die gevolge van Fe en lig beperking, of medebeperking, binne inwoner fitoplankton te bepaal. Ruimtelike en temporale variasies in fitoplankton reaksie was bestudeer om wisselende gevolge van die beperking oor watermassas en verskillende stadiums van bloei afname in die studie area te bepaal. Die gekombineerde byvoeging van Fe en lig het die grootste toename in biomassa, fotosintetiese kapasiteit en voedingsopname gegee. Ter ondersteuning van die getoetste hipoteses, veranderinge in die fotosintetiese apparaat het gelei tot veranderinge in die fotosintetiese doeltreffendheid en groei van die SO fitoplankton, as 'n gevolg van variasies in Fe en lig beskikbaarheid. Veranderlikheid is ook waargeneem in die reaksie van fitoplankton om Fe en lig wysigings weens die ruimtelike en tydelike variasie in inwoner fitoplankton gemeenskappe. Dus was dit by die gevolgtrekking gekom dat beide Fe en lig beduidende kontrole in die inwoner fitoplankton fotosintetiese apparaat, fotosintetiese vermoëns, organiese koolstof binding en daarom die biogeochemiese siklusse binne die Atlantiese sektor van die SO.

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Der Einfluß eines Seherstroms auf die Ausbreitung langer barotroper Wellen wird untersucht. Der Antarktische Zirkumpolarstrom ist als eine zonale Scherströmung zu betrachten. Wir zeigen auf einer ß-Ebene, daß der Antarktische Zirkumpolarstrom für zonal sich ausbreitende Wellen als Wellenleiter wirkt. Für den linearen Fall des Scherstromes wird die analytische Lösung angegeben. Die gebundenen Wellen sind meridional modal strukturiert und bewegen sich mit einer Gruppengeschwindigkeit von rund 0.02ms·1 von West nach Ost (alle). / We study the influence of a shear current on barotropic long wave propagation. The Antarctic Circumpolar Current can be considered as a sheared zonal flow. We show tht on a ß-plane the Antarctic Circumpolar Current acts as a waveguide for zonally propagating waves. We give the analytical solution for the linear sheared case. The trapped waves are modal structured in the meridional direction and propagate from the West to the East (all) with a group velocity of nearly 0.02ms·1.

The last two glacial terminations represent the most recent, and best documented, periods of Earth warming in the geological record. During these terminations atmospheric CO\textsubscript{2 }rose by approximately 100 ppm and global mean temperatures increased by 4-6\textsuperscript{o}C. Whilst the driver for these deglaciations ultimately derives from changes in the insolation forcing at the edge of the atmosphere, feedbacks within the Earth\textquoteright s climate system act to amplify these small external forcings tipping the Earth from a cold glacial climate state to a warm interglacial climate state. A key question in Quaternary climate science is understanding which feedbacks are important in regulating global climate on glacial-interglacial timescales. On this topic, the Southern Ocean has long been considered to be an important player in regulating atmospheric CO\textsubscript{2 } on glacial-interglacial timescales. This thesis investigates some of the hypothesised drivers of changes in atmospheric CO\textsubscript{2 } on glacial-interglacial timescales by generating high-resolution multi-proxy records from the Southern Ocean spanning the last two glacial terminations. In particular, I focus on changes in the structure, circulation and biological productivity within the sub-Antarctic zone. A change in the deep ocean density structure has been hypothesised to have resulted in the release of CO\textsubscript{2 } from the deep ocean. Centennial records from the sub-Antarctic are used to reconstruct deep and intermediate water density for the first time. I demonstrate that timing of the major breakdown in the density gradient of the ocean significantly lagged the breakdown in the chemical gradient, suggesting that changes in the deep ocean density structure were not the major driver of the deglacial rise in atmospheric CO\textsubscript{2 }. Changes in the density structure of the Southern Ocean likely had significant implications for global circulation. In particular, the flow of low salinity water through the Drake Passage is thought to be important in setting the strength and geometry of Atlantic Overturning Circulation. Drake Passage through-flow speed was reconstructed from two sites in the central and northern margins of the Antarctic Circumpolar Current downstream of Drake Passage. These records suggest a very different structure of Antarctic Circumpolar flow through Drake Passage during glacial periods, and evidence significant changes in ocean temperature as a result of pronounced reductions in Drake Passage through-flow. The strength of the biological pump has long been identified as an important player in regulating atmospheric CO\textsubscript{2 }. In particular, a strong glacial increase in sub-Antarctic productivity has been observed at open ocean sites in the South Atlantic and Indian Ocean. However, the glacial-interglacial changes in productivity in sub-Antarctic shelf settings are less well-documented. The new high-resolution records presented here from the sub-Antarctic southwest Atlantic suggest a significant change in the CaCO\textsubscript{3}:C\textsubscript{org} ratio which likely has implications for the surface ocean\textquoteright s ability to uptake CO\textsubscript{2 }.

Little is known about the factors driving the cycle of the climate-active gas dimethylsulfide (DMS) and of its precursor the metabolite dimethylsulfoniopropionate (DMSP) in sea ice. To date, studies have focused on biotic factors, linking high DMSP concentrations to the high biomass of sympagic communities, and to physiological adaptations to the low temperatures and high salinities of the brine habitat. This thesis presents an approach integrating biotic and abiotic factors, investigating the influence of ice growth processes and brine dynamics on the DMS cycle. First, brine dynamics from growth to melt are explored based on ice temperature and salinity profiles measured in the Arctic. A strong but brief desalination phase is identified in spring. Using calculated proxies of permeability (brine volume fraction) and of the intensity of brine convection (Rayleigh number), this phase is shown to correspond to full-depth gravity drainage initiated by restored connectivity of brines on warming. Full-depth gravity drainage is crucial for the vertical transfer of DMS-compounds at the ice-ocean interface. This physical background is then used to investigate the spatio-temporal variability of DMS in Arctic sea ice during a year-round survey in Amundsen Gulf. The influence of processes such as scavenging and brine convection on the DMS cycle is shown, and the first combined measurement of DMS, DMSP, and dimethylsulfoxide (DMSO), a compound acting as source/sink for DMS through photo-chemical and bacterial processes, is presented. DMSO is shown to dominate the dimethylated sulfur pool in surface ice when the snow cover is low. Based on correlations with irradiance, it is suggested that this DMSO originates from photo-chemical oxidation of DMS trapped in impermeable ice. Finally, the spatio-temporal variability of DMS in Antarctic sea ice is investigated during another year-round survey in McMurdo Sound. Platelet crystals growth under the influence of ice-shelf waters are shown to favor the incorporation of strong DMSP producers, to increase the environmental stress on cells, and to favor the accumulation of DMS,P by reducing permeability. The increase of permeability on warming is shown to trigger strong release of DMS in the ocean and a vertical redistribution of DMSP in the ice cover.

Aspects of the physiology and anatomy of cardiac and skeletal muscle in south polar notothenioid fish have been investigated. Relative ventricle weights for the haemoglobinless Chaenocephalus aceratus (family Channichthyidae) were approximately three times greater than for sympatric 'red-blooded' species. The ventricle in the channichthyid was 'sac-like' in shape and had an entirely trabecular myocardium: these characteristics were associated with low maximum myocardial power outputs (1.46mW(g ventricle weight) ⁻¹). The blood supply to the ventricle was through the venous lacunary circuit and vessels in the subepicardium. The myoglobin-poor ventricular myocardium in C.aceratus was composed of myocytes and granulated non-contractile cells. Myocardial cytochrome oxidase activity (34 μmoles g⁻¹min⁻¹) at O°C was similar to that of warmer-water species with myoglobin-rich ventricles. This suggests that the channichthyid has achieved compensation for the rate depressing effects of the low temperatures and low myoglobin concentrations on oxidative metabolism. Morphometric analyses of the myocytes in C.aceratus indicated that they had higher mitochondrial (0.43) and lower myofibrillar (0.31) volume densities than other teleosts. It was proposed that the proliferation of mitochondria serves to maintain high aerobic capacities by reducing oxygen diffusion distances between the lacunae and the myocytes. The anatomy of the pectoral fin muscles in N.neglecta (family Nototheniidae) has been described. Six muscles (2.49% of total body weight) articulated the fin blade. These were composed of a core of small diameter fibres (18-99μm) which stained intensely for markers of aerobic metabolism. Overlying these was a layer of larger diameter fibres (24-156μm) which stained poorly for these markers. The two fibre types were also differentiated on the basis of their mechanical properties: demembranated preparations of the larger diameter fibres generated approximately twice the tensions and had twice the unloaded contraction velocities of the small diameter fibres. Despite these differences however, the fibres could not easily be differentiated on the basis of the pH stabilities of their myosins. At 1°C the maximum isometric tension (Po) generated by both pectoral fibre types in N.neglecta demonstrated incomplete temperature compensation compared to published values for homologous fibres in warm-water teleosts. Unloaded contraction velocity (Vmax) was not temperature compensated. In addition to Po, adaptive modifications in the curvature of the force-velocity curves were identified in the nototheniid which served to enhance power output at low temperatures. Between -5 and +10°C Po was relatively temperature independent (R₁₀ = approximately 1.2) whereas the temperature coefficent of Vmax was high (Q₁₀ = approximately 2). Following activations in excess of 12°C both fibre types failed to relax completely. This suggests that adaptations in the contractile proteins which conferred high power outputs at low temperatures were associated with a limitation in the temperature range over which they could maintain function. Simultaneous measurements were made of force generation and myofibrillar ATP hydrolysis during isometric contractions in demembranated white trunk fibres isolated from teleosts adapted to different thermal environments. ATP hydrolysis was quantified using a novel technique which allowed the fibres to be activated in the presence of an ATP regenerating system based on phosphocreatine and creatine phosphokinase. ATP activity was determined by measuring the increase in free creatine in the activating solution. The results obtained indicated that the economy of contraction (tension/ATP hydrolysed) was substantially higher in the fibres from Notothenia neglecta than those from warmer-water species at their preferred body temperatures.