Geoscience Australia carried out a marine survey on Carnarvon shelf (WA) in 2008 (SOL4769) to map seabed bathymetry and characterise benthic environments through colocated sampling of surface sediments and infauna, observation of benthic habitats using underwater towed video and stills photography, and measurement of ocean tides and wavegenerated currents. Data and samples were acquired using the Australian Institute of Marine Science (AIMS) Research Vessel Solander. Bathymetric mapping, sampling and video transects were completed in three survey areas that extended seaward from Ningaloo Reef to the shelf edge, including: Mandu Creek (80 sq km); Point Cloates (281 sq km), and; Gnaraloo (321 sq km). Additional bathymetric mapping (but no sampling or video) was completed between Mandu creek and Point Cloates, covering 277 sq km and north of Mandu Creek, covering 79 sq km. Two oceanographic moorings were deployed in the Point Cloates survey area. The survey also mapped and sampled an area to the northeast of the Muiron Islands covering 52 sq km. cloates_3m is an ArcINFO grid of Point Cloates of Carnarvon Shelf survey area produced from the processed EM3002 bathymetry data using the CARIS HIPS and SIPS software

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Geoscience Australia carried out marine surveys in southeast Tasmania in 2008 and 2009 (GA0315) to map seabed bathymetry and characterise benthic environments through observation of habitats using underwater towed video. Data was acquired using the Tasmania Aquaculture and Fisheries Institute (TAFI) Research Vessel Challenger. Bathymetric mapping was undertaken in seven survey areas, including: Freycinet Pensinula (83 sq km, east coast and shelf); Tasman Peninsula (117 sq km, east coast and shelf); Port Arthur and adjacent open coast (17 sq km); The Friars (41 sq km, south of Bruny Island); lower Huon River estuary (39 sq km); D Entrecastreaux Channel (7 sq km, at Tinderbox north of Bruny Island), and; Maria Island (3 sq km, western side). Video characterisations of the seabed concentrated on areas of bedrock reef and adjacent seabed in all mapped areas, except for D Entrecastreaux Channel and Maria Island. fortescue_160 is an ArcINFO grid of the Tasman Peninsula survey area produced from the processed EM3002 bathymetry data using the CARIS HIPS and SIPS software.

Geoscience Australia carried out marine surveys in southeast Tasmania in 2008 and 2009 (GA0315) to map seabed bathymetry and characterise benthic environments through observation of habitats using underwater towed video. Data was acquired using the Tasmania Aquaculture and Fisheries Institute (TAFI) Research Vessel Challenger. Bathymetric mapping was undertaken in seven survey areas, including: Freycinet Pensinula (83 sq km, east coast and shelf); Tasman Peninsula (117 sq km, east coast and shelf); Port Arthur and adjacent open coast (17 sq km); The Friars (41 sq km, south of Bruny Island); lower Huon River estuary (39 sq km); D Entrecastreaux Channel (7 sq km, at Tinderbox north of Bruny Island), and; Maria Island (3 sq km, western side). Video characterisations of the seabed concentrated on areas of bedrock reef and adjacent seabed in all mapped areas, except for D Entrecastreaux Channel and Maria Island. fortescue_2m is an ArcGIS layer of the backscatter grid of the Tasman Peninsula survey arae produced from the processed EM3002 backscatter data of the survey area using the CMST-GA MB Process

Sniffer Files The 'Sniffer' or Direct Hydrocarbon Detection (DHD) technique used to detect hydrocarbon seepage offshore involves towing a submerged tow-fish close to the seafloor and continuously pumping seawater into a geochemical laboratory on board where the hydrocarbons are extracted and measured by gas chromatography. The Direct Hydrocarbon Detection (DHD) method continuously analyses C1-C8 hydrocarbons within seawater. The method used on the RV Rig Seismic is as follows. Seawater is continuously delivered into the geochemical laboratory onboard the ship via a submersible fish (which is towed approximately 10 m above the seafloor). The seawater is degassed in a vacuum chamber and the resulting headspace gas is injected into three gas chromatographs, which sequentially sample the flowing gas stream and measure a variety of light hydrocarbons. Total hydrocarbons (THC) are measured every thirty seconds, light hydrocarbons (C1-C4) are measured every two minutes and C5 to C8 are measured every 8 minutes. Fluorometer and Aquatrack Fil In October 1998, the Australian Geological Survey Organisation (AGSO) carried out field trials of three commercially available towed fluorometers; Aquatracka (Chelsea Instruments), SAFIRE (WetLabs), FLF (WetLabs). These instruments were pre-selected on manufacturer specifications as potentially the most suitable, compared to other fluorometers currently on the market, for the detection of polycyclic aromatic hydrocarbons (PAH) present in crude oils seeping into the marine environment. The fluorometers were set with an excitation wavelength in the range 239 nm to 260 nm and fluorescence was monitored over the range 340 nm to 360 nm. SAFIRE is a multi-wavelength instrument, which enabled simultaneous use of several excitation and emission wavelengths. All three fluorometers were mounted on deck and seawater was pumped through them. The Aquatracka instrument analysed deep water pumped to the surface by the "Sniffer" submersible system.

A contoured (interval 10m) general reference map of Christmas Island showing settlement, mining areas, railways, roads and tracks.

Road centrelines with road names and classification of primary, secondary or track, and sealed or unsealed.

This is a national seamless data product aimed at regional or national applications. TOPO 2.5M 1998 contains a small scale vector representation of the topographic mapping features of Australia. The data include the following themes: Hydrography - drainage networks including rivers, lakes and offshore features; and Infrastructure - roads, railways, localities and built-up areas. Data was primarily sourced from Geoscience Australia`s GEODATA TOPO-250K data set however all features were revised in 1998. Free online and CD-ROM (fee applies).

The map provides a visual representation of the gravel content of seabed sediments expressed as a weight percentage. The data are represented from 0 to 100%. The data on which this map is based were compiled from Geoscience Australia's marine sediment database (MARS - http://www.ga.gov.au/oracle/mars/).

Geoscience Australia is supporting the exploration and development of offshore oil and gas resources and establishment of Australia's national representative system of marine protected areas through provision of spatial information about the physical and biological character of the seabed. Central to this approach is prediction of Australia's seabed biodiversity from spatially continuous data of physical seabed properties. However, information for these properties is usually collected at sparsely-distributed discrete locations, particularly in the deep ocean. Thus, methods for generating spatially continuous information from point samples become essential tools. Such methods are, however, often data- or even variable- specific and it is difficult to select an appropriate method for any given dataset. Improving the accuracy of these physical data for biodiversity prediction, by searching for the most robust spatial interpolation methods to predict physical seabed properties, is essential to better inform resource management practises. In this regard, we conducted a simulation experiment to compare the performance of statistical and mathematical methods for spatial interpolation using samples of seabed mud content across the Australian margin. Five factors that affect the accuracy of spatial interpolation were considered: 1) region; 2) statistical method; 3) sample density; 4) searching neighbourhood; and 5) sample stratification by geomorphic provinces. Bathymetry, distance-to-coast and slope were used as secondary variables. In this study, we only report the results of the comparison of 14 methods (37 sub-methods) using samples of seabed mud content with five levels of sample density across the southwest Australian margin. The results of the simulation experiment can be applied to spatial data modelling of various physical parameters in different disciplines and have application to a variety of resource management applications for Australia's marine region.