resource management
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This document represents part of Geoscience Australia's contribution to the National Estuaries Assessment and Management (NE) project, Theme 5 (Assessment and Monitoring), Task 5A 'Conceptual Models of Australian Estuaries and Coastal Waterways'. The report contains comprehensive conceptual models of the biophysical processes that operate in a wide range of estuaries and coastal waterways found around Australia. Geomorphic conceptual models have been developed for each of the seven types of Australian estuaries and coastal waterways. Each conceptual model comprises a three-dimensional block diagram depicting detailed summaries of the structure, evolutionary characteristics, and geomorphology of each coastal waterway type, which are ?overlain? by flow diagrams that depict some of the important biotic and abiotic processes, namely: hydrology, sediment dynamics, and nutrient dynamics. Geomorphology was used as the common 'base layer' in the conceptual models, because sediment is the fundamental, underlying substrate upon which all other estuarine processes depend and operate. In the conceptual models, wave-dominated systems are depicted as having a relatively narrow entrance that restricts marine flushing, and low water-column turbidity except during extreme events. Tide-dominated systems feature relatively wide entrances, which likely promote efficient marine flushing, very large relative areas of intertidal habitats, and naturally high turbidity due to strong turbulence induced by tidal currents. Strong evidence exists suggesting that estuaries (both wave- and tide-dominated) are the most efficient 'traps' for terrigenous and marine sediments, and these are depicted as providing the most significant potential for trapping and processing of terrigenous nutrient loads. Intertidal areas, such as mangroves and saltmarshes, and also the central basins of wave-dominated estuaries and coastal lagoons, are likely to accumulate the majority of trapped sediments and nutrients. Conceptual model diagrams, with overlays representing environmental processes, can be used as part of a decision support system for environmental managers, and as a tool for comparative assessment in which a more integrative and shared vision of the relationship between components in an ecosystem can be applied.
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The introduction of a deuterium-enriched tracer to benthic incubation chambers emplaced on the sea floor of Port Phillip Bay provides a method of modelling bio-irrigation within the sediments. Plots of deuterium v. incubation time reveal that all seven chambers, emplaced at four sites, indicate nondiffusive transport of pore-water solutes across the sediment-water interface. Modelling indicates that advection of overlying chamber water must occur to depths of 20-50 cm below the interface and at rates between 150 and 700 mL h-1. Multiple chambers deployed in the same region within the bay are consistent with respect to bio-irrigation depth and rate. This indicates that the distribution of infauna responsible for irrigation is quite consistent within regions defined by sediment type and depth. However, various regions in the bay show distinctly different irrigation rates; thus the distribution and/or activity of infauna is not constant throughout the bay. At the lower rate of pore-water advection, the entire water column in Port Phillip Bay passes through the sediments within 200 days. Dissolved caesium, injected into the chamber, is also an effective tracer of bio-irrigation although adsorption onto sediment particles increases the uncertainty of model results.
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From 1995 to 2000 information from the federal and state governments was compiled for Comprehensive Regional Assessments (CRA), which formed the basis for Regional Forest Agreements (RFA) that identified areas for conservation to meet targets agreed by the Commonwealth Government with the United Nations. This CD was created as part of GA's contribution to the East Gippsland CRA. It contains final versions of all data coverages and shapefiles, AMLs and Graphics files in ArcInfo (.gra), postscript (.ps) and Web ready (.gif) formats, and final versions of documents, maps and figures submitted for publishing.
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Australia's Identified Mineral Resources is an annual nation-wide assessment of Australia's ore reserves and mineral resources.
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This record is a review and synthesis of geological research undertaken along the south western margin of Australia. The record has been written in support of regional marine planning and provides fundamental baseline scientific information for the South Western Marine Planning Area.
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This map shows Western Australian and Commonwealth fishing closures, marine conservation areas and maritime boundaries for the area from Perth south, then east past Albany. It has been produced for the National Oceans Office.
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This record is a review and synthesis of geological research undertaken along the northern margin of Australia. The record has been written in support of regional marine planning and provides fundamental baseline scientific information for the Northern Planning Area.
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A report showing, in so far as figures are available, the salient features of the mineral industry just prior to the outbreak of the Second World War.
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Recently, it was desired for engineering and other purposes to test the micaceous marls and the glauconitic sandstone below the bottom of the shaft. It was decided to put down a diamond drill hole and to use the cores for necessary testing. This report deals mainly with the examination of the cores of glauconitic sandstone obtained from the drill hole. An attempt has been made to correlate much of the available data on the Lakes Entrance field which has a bearing on the Lakes Entrance oil project, and to provide a summary of the occurrence and distribution of oil in the glauconitic sandstone. Finally the report includes a critical examination of the factors influencing the recovery of oil from the glauconitic sandstone by horizontal oil wells, and an estimate of the percentage of oil which might be recoverable from a given area at Lakes Entrance.
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Coastal lagoons are a type of estuary, which has highly variable assemblages of primary producer groups. A classification is derived distinguishing microphytobenthos-dominated, perennial and ephemeral submerged aquatic vegetation-dominated, and nutrient- and light-limited phytoplankton-dominated lagoons. The principle variables required for the classification are bathymetry, light attenuation and initial solar radiation, dissolved inorganic nitrogen concentration and the area covered by ephemeral and perennial submerged aquatic vegetation. Biogeochemical processes and system-wide nutrient dynamics are inherently coupled to the distribution of primary producer groups, so that the classification provides inferences on water quality and ecosystem functioning for different lagoon types and supports the development of management plans and ecological status assessments. Four case studies representing different lagoon types from the temperate south-eastern and south-western coast of Australia are presented. It is demonstrated that the distribution of primary producer groups, and consequently the lagoon type, can be temporarily variable, e.g. as a function of seasonal solar radiation and light attenuation, the water level in a closed lagoon or the degree of eutrophication.