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Biogeochemical constraints on the growth and nutrition of the seagrass Halophila ovalis in the Swan River EstuaryKilminster, Kieryn Lee January 2006 (has links)
[Truncated abstract] Biogeochemical processes in seagrass sediments influence growth and nutrition of seagrasses. This thesis investigates the below-ground interactions between biotic and abiotic factors that influence seagrass nutrition and growth, with focus on a small species of seagrass, Halophila ovalis (R. Br.) Hook ƒ., from the Swan River Estuary, Western Australia. Seagrass showed significantly lower growth and an increase in leaf nitrogen and phosphorus concentrations with increased organic matter loading. With maximal light reduction, lower growth rates and average leaf weights were observed, and leaf nitrogen and phosphorus concentrations were higher. Light reduction was also shown to increase bioavailability of inorganic nutrients within porewater of seagrass sediment . . . Sulphide was hypothesised to have an inhibitory effect on nutrient uptake of Halophila ovalis. Below-ground sulphide inhibits the photosynthetic efficiency of photosystem II at sulphide concentrations greater than 1 mM. Sulphide exposure enhanced phosphate uptake, with no significant effect on ammonium uptake of H. ovalis. This thesis demonstrates that biogeochemical processes both constrain the potential growth of seagrasses and influence the nutrient status of seagrass tissue. Consideration of the influence of sulphide stress on seagrasses is likely to be particularly important for anthropogenically influenced aquatic systems, where inputs of organic matter are enriched relative to pristine ecosystems. A better understanding of biogeochemical processes will allow researchers to predict how future changes in sediment chemistry will influence seagrass meadows.
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To hunt and to hold : Martu Aboriginal people's uses and knowledge of their country, with implications for co-management in Karlamilyi (Rudall River) National Park and the Great Sandy Desert, Western AustraliaWalsh, Fiona Jane, January 2009 (has links)
[Truncated abstract] This ethnoecological study examines land uses by modern Martu Aboriginal people on their country. They occupy very remote settlementsParnngurr, Punmu and Kunawarritjiin the Great and Little Sandy Deserts. In 1990, their country included Crown Lands and Rudall River National Park. The study investigated the proposition that the knowledge and practices of Martu were of direct relevance to ecosystem processes and national park management. This research commenced in the wider Australian research context of the late 1980s early 90s when prevailing questions were about the role of customary harvest within contemporary Aboriginal society (Altman 1987; Devitt 1988) and the sustainability of species-specific harvests by Australian indigenous people (Bomford & Caughley 1996). Separately, there was a national line of enquiry into Aboriginal roles in natural resource and protected area management (Williams & Hunn 1986; Birckhead et al. 1992). The field work underpinning this study was done in 19861988 and quantitative data collected in 1990 whilst the researcher lived on Martu settlements. Ethnographic information was gathered from informal discussions, semi-structured interviews and participant observation on trips undertaken by Martu. A variety of parameters was recorded for each trip in 1990. On trips accompanied by the researcher, details on the plant and animal species collected were quantified. Martu knowledge and observations of Martu behaviour are interpreted in terms of the variety of land uses conducted and transport strategies including vehicle use; the significance of different species collected; socio-economic features of bush food collection; spatio-temporal patterns of foraging; and, the 'management' of species and lands by Martu. The research found that in 1990, hunting and gathering were major activities within the suite of land uses practiced by Martu. At least 40% of trips from the settlements were principally to hunt. More than 43 animal species and 37 plant food species were reported to be collected during the study; additionally, species were gathered for firewood, medicines and timber artefacts. Customary harvesting persisted because of the need for sustenance, particularly when there were low store supplies, as well as other reasons. The weight of bush meats hunted at least equalled and, occasionally, was three times greater than the weights of store meats available to Parnngurr residents. ... Paradoxically, hunting was a subject of significant difference despite it being the principal activity driving Martu expertise and practice. There is potential for comanagement in the National Park but it remains contingent on many factors between both Martu and DEC as well as external to them. The dissertation suggests practical strategies to enhance co-management.
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Calcareous nannofossil and foraminiferal analysis of the middle to upper cretaceous Bathurst Island Group, Northern Bonaparte Basin and Darwin Shelf, Northern AustraliaCampbell, Robert John January 2003 (has links)
[Truncated abstract] The Northern Bonaparte Basin and adjacent Darwin Shelf form part of a major petroleum province on the northwestern margin of Australia. The middle to Late Cretaceous Bathurst Island Group consists of siliciclastic and pelagic carbonate strata that form the regional seal to underlying Upper Jurassic and Lower Cretaceous reservoir sandstones. The Bathurst Island Group has previously been subdivided into four stratigraphic sequences or ‘play intervals’ bound by regional disconformities in the Valanginian (KV horizon), Lower Aptian (KA horizon), upper Lower Cenomanian (KC horizon), Middle Campanian (KSC horizon), and at the CretaceousPaleocene boundary (T horizon). Correlation of these sedimentary packages and stratigraphic surfaces requires high-resolution calcareous microfossil biostratigraphy, while palaeobathymetric determinations based on benthonic foraminiferal assemblages are important for determining the subsidence history of the area and relative sea-level changes. This study presents the first detailed stratigraphic distributions, taxonomic lists and illustrations of foraminifera and calcareous nannofossils from the Bathurst Island Group of the Northern Bonaparte Basin and Darwin Shelf. A biostratigraphic framework has been constructed for the study area incorporating ‘standard’ (Tethyan) Cretaceous planktonic foraminiferal and calcareous nannofossil events where applicable, and integrating locally defined events where necessary. This framework allows Cretaceous strata to be correlated regionally across the study area and to the global chronostratigraphic scale. Correlation of the Northern Bonaparte Basin and Darwin Shelf strata to the Cretaceous Stages and international time scale is based on recent ties of nannofossil and foraminiferal events to macrofossil zones and palaeomagnetic polarity chrons at ratified and proposed Global Stratotype Sections and Points (GSSPs). Calcareous nannofossil events recorded in the study area that are critical for defining stage boundaries include the lowest occurrences of Prediscosphaera columnata, Micula decussata, Lithastrinus grillii, and Aspidolithus parcus parcus, and the highest occurrences of Helenea chiastia, Lithastrinus moratus, Aspidolithus parcus constrictus, and Eiffellithus eximius. Important planktonic foraminiferal events for correlation include the lowest occurrences of Rotalipora gr. globotruncanoides, and Dicarinella asymetrica, and the highest occurrences of Planomalina buxtorfi, Rotalipora cushmani, and Dicarinella asymetrica. During the middle to Late Cretaceous the Northern Bonaparte Basin and Darwin Shelf occupied mid-high palaeolatitudes between 35ºS to 45ºS. These palaeolatitudes are reflected in the transitional character of the planktonic microfossil assemblages, which combine elements of the low-latitude, warm-water Tethyan Province to the north and the cool-water high-latitude Austral Province to the south. ‘Standard’ Tethyan zonations are most applicable for uppermost AlbianMiddle Campanian strata because equator-to-pole temperature gradients were weakly developed, and global climate was warm and equable during this interval. These conditions resulted in broad latitudinal distributions for Tethyan marker species, and consequently most UC calcareous nannofossil zones and European-Mediterranean planktonic foraminiferal zones are recognised. In contrast, the EarlyLate Albian and the late Middle CampanianMaastrichtian were intervals of greater bioprovinciality and stronger palaeotemperature gradients. In these intervals application of the Tethyan zonations is more difficult, and a number of the Tethyan biostratigraphic markers are absent from the study area (e.g. Ticinella species in the Albian and Radotruncana calcarata in the Late Campanian). Cretaceous palaeobathymetric reconstruction of the study area is based on comparison of the foraminiferal assemblages with those of previous Cretaceous palaeobathymetric studies. Marginal marine assemblages consist solely of low diversity siliceous agglutinated foraminifera (e.g. Trochammina). Inner and middle neritic water depths (0-100 m) contain rare to common planktonic foraminifera (mainly globigerine forms), robertinids (e.g. Epistomina), siliceous agglutinates, lagenids, buliminids (e.g. Neobulimina), and rotaliids. The outer neritic zone (100-200 m water depth) contains abundant planktonic foraminifera (keeled and globigerine), calcareous agglutinates (e.g. Dorothia), and diverse lagenids, buliminids, and rotaliids. Upper-middle bathyal water depths (200-1000 m) are characterised by abundant planktonic foraminifera, common siliceous agglutinated taxa (e.g. Glomospira), rare to common Osangularia, and globular species of Gyroidinoides, Pullenia, and Paralabamina.
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Playas of the Yarra Yarra drainage system, Western AustraliaBoggs, Dimity January 2009 (has links)
This thesis examines playas as integrated ecosystems, through investigation of long- and short-term processes associated with playa geomorphology, hydrology and diatom ecology, in playas of the Yarra Yarra drainage system of Western Australia. This landscape approach was conducted at a range of scales and consequently revealed a level of heterogeneity not previously described in Australian playas. The key result and common thread linking the three facets of the playas investigated is the importance of hydroperiod in defining the playa environment. The morphology and distribution of playas are described and the results presented of an examination of potential mechanisms determining intra-system variability. Measurements of the physical attributes of the playas, including length, area, shape, density and orientation, were made through Geographic Information System analysis and detailed interpretation of aerial photography. Two main morphological groups are distinguished: small (<10 ha), elliptical to circular playas with a NNW-SSE orientation; and large (>30 ha), elongated playas. Regional patterns in geomorphic attributes are markedly different between the west and east sides of the system. The boundary between the two regions coincides approximately with rainfall distribution. In this respect, climate is an overarching driver of geomorphological variation but sub-catchment characteristics are also critical determinants. Littoral drift and segmentation processes that are common to coastal lagoons but not commonly described in playas were identified from visual interpretation of aerial photographs of spits, bars and cuspate shorelines. Six small playas, representing an hydrological continuum from mostly wet to mostly dry, were selected for investigation of their hydrology and diatom ecology, enabling assessment ii of the variability of hydrology, hydrochemistry and of the effects of different hydrological environments on the distribution of taxa. Hydroperiod was highly variable and central to determining playa geomorphology and biology. In the six playas it ranged from 19 to over 211 days, and filling frequency from 1 to 3 cycles between 2002 and 2004, reflecting rainfall and sub-catchment variability. Monitoring a series of nested piezometers revealed that the playas were net discharge points for ground water over the period of survey. However, small local vertical head variations indicate ground water does not discharge at the same rate across the playa surfaces and that playas may have short-lived phases of ground water recharge. Hydrochemically, the playas are typical of salt lakes in Australia. They displayed a wide range of salinity values, neutral to alkaline pH and ionic composition similar to sea water. It is postulated that the geochemical evolution of waters in the playas follows a pathway where low salinity recharge waters with dilute sea water salts progress to Na-Cl dominated brines through evaporative concentration. Surface waters showed an ionic dominance consistent with sea water with minor variations attributed to transitional phases in the geochemical evolution of the waters. Shallow ground waters showed a common and consistent pattern of ionic dominance: Na+ >Mg2+ >K+ >Ca2+ : Cl- >SO4 2- >HCO3 ->CO3 2-.
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Small, no-take marine protected areas and wave exposure affect temperate, subtidal reef communities at Marmion Marine Park, Western AustraliaRyan, Kylie A. January 2008 (has links)
[Truncated abstract] The ecological effects of marine protected areas (MPAs) in temperate ecosystems are poorly understood relative to their tropical counterparts. The limited number of rigorous empirical studies supporting existing theoretical models, increasing public awareness of the importance of marine conservation strategies and legislative requirements to review management effectiveness provide further impetus to study temperate MPAs. Investigations should consider confounding effects of natural variability if MPA effects are to be clearly demonstrated. This research helps to address these needs by investigating the short term effects of sanctuary zones (no-take MPAs where fishing is prohibited) and wave exposure at Marmion Marine Park, Western Australia. The three sanctuary zones at Marmion Marine Park are extremely small (0.061 0.279 km2) compared to most reported in the literature. The sanctuary zones are nested within a larger, fished zone (94.95 km2). The sanctuary zones have been protected from fishing since the year 2000. A post-hoc, asymmetrical sampling design was used in this study and involved surveys of fishes, mobile invertebrates and macroalgae at one sanctuary zone and two fished sites (controls) at each of three successive, subtidal reef lines. The three reef lines are exposed to a gradient in wave energy. The size structure and abundance of the heavily exploited Panulirus cygnus (Western Rock Lobster) were positively affected by protection from fishing in sanctuary zones, despite the highly mobile nature of this migratory species. The mean abundance of legal size lobsters was higher in sanctuary zones compared to fished sites during an interannual study (2003, 2005 and 2006). The total abundance of lobsters and the mean abundance of legal size lobsters were higher at inshore and offshore sanctuary zones compared to fished control sites during a 2005/2006 fishing season study. These zoning effects did not vary with the time of survey. ... Furthermore, the abundance of large lobsters in sanctuary zones decreased with the duration of the 2005/2006 fishing season. Similarly, it is likely that sanctuary zones are too small relative to the movement of fishes to adequately protect stocks of some targeted species. The small sanctuary zones at Marmion are unlikely to offer protection to highly mobile species over the long term. And finally, ecological assemblages within each level of wave exposure are distinct. Consequently for each assemblage type, the current reserve design does not include replication of sanctuary zones and does not offer any 'insurance' in the event of isolated impacts affecting a particular zone. This study has identified the benefits and deficiencies of the design and function of small no-take temperate MPAs in Western Australia. An increase in the size and number of sanctuary zones within each wave exposure level will help to address the v shortfalls of the zoning scheme and enhance the conservation benefits of management at Marmion Marine Park. More generally, this study demonstrates that the mobility of the species to be protected from fishing should be considered when designing MPAs. Lessons learned from this work will be beneficial for the future management and conservation of resources in the region and elsewhere.
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Patterns of coastal tourism growth and multiple dwelling : implications for informal camping along the Ningaloo coastlineLawrie, Misty Suanne January 2008 (has links)
Over the past few decades, the development of coastal areas has become an increasingly contested arena. For many years, tourism in remote coastal areas has been the preserve of a few intrepid campers, surfers and recreational fishers. More recently, however, numbers along parts of the coast have increased rapidly, not only contributing to an expansion of camping activity, but also pressure for more commercially oriented tourism. This has contributed to concerns about the environmental sustainability of tourism in remote coastal areas. Governments have increasingly been faced with the challenge of balancing ecological concerns with the pursuit of economic development. Adding to the complexity are the differing needs and demands of various segments of the tourism market all looking to enjoy particular places. Balancing the demands of campers, backpackers, package tourists and others in a single place is often wrought with conflict. This study explores some of these issues in a remote coastal area in Western Australia. The Ningaloo coast has evolved from a difficult to reach destination used by a small number of campers, to one of Western Australia's most popular tourist destinations in just two decades. The thesis examines the factors underlying the growth and change of tourism in the region, tracing its evolution from a few small rudimentary campsites to proposals for large scale resort developments. Of particular interest to this thesis is how planning and policy processes aim to address developmental pressures and resource use/planning conflicts. Additionally, this study provides an insight into the issues facing the informal, long term camper as the traditional segment of Ningaloo's tourism market. It examines how current planning and policy for the Ningaloo coastline affects this group by reshaping traditional tourism use of the area.
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An historical analysis of the structures established for the provision of Anglican schools in the diocese of Perth, Western Australia between 1917 and 1992Melville, William Ian January 2006 (has links)
[Truncated abstract] Within the State of Western Australia, from its early years, education has been provided not only by the State, but also by religious denominations, particularly the Catholic Church, the Anglican Church and other Christian groups. This thesis is concerned with Anglican education in the State from the years 1917-92. The particular focus is on the structures established for the provision of Anglican education in the Diocese of Perth throughout the period. The central argument of the thesis is as follows. During the period 1917-92, the structures established for the provision of Anglican education in the Diocese of Perth changed across four subperiods: 1917-50, 1951-60, 1961-80 and 1981-92. During the first subperiod, provision was made under structures which allow for the schools which existed to be classified according to three ‘types’: ‘religious-order schools’, ‘parish schools’, and ‘schools of the Council for Church of England Schools’. The first two types continued during the second subperiod and were joined by two new types, namely, ‘Perth Diocesan Trustees’ schools’ and ‘synod schools’, while ‘schools of the Council for Church of England Schools’ceased as a type. During the third subperiod ‘synod schools’ continued as a type, but the other three types ceased to exist. At the same time, one new type emerged, namely, ‘schools of the Church of England Schools’ Trust’. During the fourth subperiod there were also two types of schools within the Diocese, but the situation was not the same as in the previous subperiod because while ‘synod schools’ continued as a type, ‘Perth Diocesan Trustees’ schools’ ceased to exist. Furthermore, a new type was established, namely ‘schools of the Anglican Schools Commission’. This two-type structure for provision which was established during the sub-period 1981-92, is still that which exists to the present day for the provision of Anglican education within the Diocese of Perth.
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A distributed conceptual model for stream salinity generation processes : a systematic data-based approachBari, Mohammed A. January 2006 (has links)
[Truncated abstract] During the last fifty years mathematical models of catchment hydrology have been widely developed and used for hydrologic forecasting, design and water resources management. Most of these models need large numbers of parameters to represent the flow generation process. The model parameters are estimated through calibration techniques and often lead to ‘unrealistic’ values due to structural error in the model formulations. This thesis presents a new strategy for developing catchment hydrology models for representing streamflow and salinity generation processes. The strategy seeks to ‘learn from data’ in order to specify a conceptual framework that is appropriate for the particular space and time scale under consideration. Initially, the conceptual framework is developed by considering large space and time scales. The space and time scales are then progressively reduced and conceptual model complexity systematically increased until ultimately, an adequate simulation of daily streamflow and salinity is achieved. This strategy leads to identification of a few key physically meaningful parameters, most of which can be estimated a priori and with minimal or no calibration. Initially, the annual streamflow data from ten experimental catchments (control and cleared for agriculture) were analysed. The streamflow increased in two phases: (i) immediately after clearing due to reduced evapotranspiration, and (ii) through an increase in stream zone saturated area. The annual evapotranspiration losses from native vegetation and pasture, the ‘excess’ water (resulting from reduced transpiration after land use change), runoff and deep storage were estimated by a simple water balance model. The model parameters are obtained a priori without calibration. The annual model was then elaborated by analysing the monthly rainfall-runoff, groundwater and soil moisture data from four experimental catchments. Ernies (control, fully forested) and Lemon (53% cleared) catchments are located in zone with a mean annual rainfall of 725 mm. Salmon (control, fully forested) and Wights (100% cleared) are located in zone with mean annual rainfall of 1125 mm. Groundwater levels rose and the stream zone saturated area increased significantly after clearing. From analysis of this data it was evident that at a monthly time step the conceptual model framework needed to include a systematic gain/loss to storage component in order to adequately describe the observed lags between peak monthly rainfall and runoff.
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Improving model structure and reducing parameter uncertainty in conceptual water balance models with the use of auxiliary dataSon, Kyongho January 2006 (has links)
[Truncated abstract] The use of uncertainty analysis is gaining considerable attention in catchment hydrological modeling. In particular, the choice of an appropriate model structure, the identifiability of parameter values, and the reduction of model predictive uncertainty are deemed as essential elements of hydrological modelling. The chosen model structure must be parsimonious, and the parameters used must either be derivable from field measured data or inferred unambiguously from analysis of catchment response data. In this thesis, a long-term water balance model for the Susannah Brook catchment in Western Australia has been pursued using the ?downward approach?, which is a systematic approach to determine the model with the minimum level of complexity, with parameter values that in theory are derivable from existing physiographic data relating to the catchment. Through the analysis of the rainfall-runoff response at different timescales, and the exploration of the climate, soil and vegetation controls on the water balance response, an initial model structure was formulated, and a priori model parameter values estimated. Further investigation with the use of auxiliary data such as deuterium concentration in the stream and groundwater level data exposed inadequacies in the model structure. Two more model structures were then proposed and investigated through formulating alternative hypotheses regarding the underlying causes of observed variability, including those associated with the absence of a contribution of deep groundwater flow to the streamflow, which was indicated by deuterium concentration and internal dynamics characterized by the observed groundwater levels. ... These differences are due to differences in the time delay between rainfall and recharge between upland and riparian regions. The ages of water recharging the groundwater and discharging from the catchment were estimated by assuming a piston flow mechanism. In the deeper, upland soils, the age of recharging water was considerably larger than the unsaturated zone delay would suggest; a recharge response 16 days after an infiltration event may involve water as much as 160 days old. On the other hand, the delay and the age of recharging water were much lower in the shallow riparian zone. Where the upland zone contributes significantly to discharge, the predicted difference between the rainfall-discharge response time and the average age of discharging water can be significant.
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Characteristics and sorption properties of charcoal in soil with a specific study of the charcoal in an arid region soil of Western AustraliaMcMahon, Claire Louise January 2006 (has links)
[Truncated abstract] Fire creates charcoal from the partial burning of biomass which results in a biologically inert form of carbonaceous (non-living) organic matter that, once integrated into soil and sediments, can persist for long periods of time. Charcoal has a large surface area with a high sorptive capacity for organic and inorganic substances. As a repository for metal and non-metal elements charcoal has been given little, if any, attention in the fields of geochemistry, agriculture and environmental monitoring . . . Despite the differences in charcoal surface area, soil charcoal achieved nearly 100% sorption of 0.5 and 5 μg/g Au from 0.03 M NaCl and 0.01M Ca(NO3)2 solution, almost independent of solution pH. At low pH, charcoal sorbed between 10 and 60% of Cu with initial additions of 2 and 20 μg Cu/g. Similarly, between 15 and 40% of Zn was sorbed by charcoal with initial additions of 5 and 40 μg Zn/g. The role of surface area in sorption of elements by charcoal is clearly only one factor that is important. Charcoal aromatic and aliphatic chemical functional groups, which can be distinguished from other forms of organic matter through spectroscopic determination, are also important in charcoal’s capacity to sorb elements. Accumulation of Be, B, Na, Mg, Al, Si, K, Ca, Ti, Mn, Co, Ni, Cu, Se, Mo, Ba, Au and Pb (out of a range of 29 elements) in soil charcoal, above the concentrations in the matrix soil and plant reference charcoal, was confirmed by ICP-MS analysis. Concentrations of V, Mn, Co, Ni, Cu, Mo, Ba, Au, Pb and Bi were higher in soil charcoal than in values quoted for gossans and pisolites in the field area region (Smith and Perdrix, 1983). Higher values of Au in soil charcoal were associated with considerable amounts of included clay minerals and higher values of other elements including Mo, Mn and Fe.
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