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  • Multibeam bathymetry gridded at 20m resolution and projected to WGS84 UTM zone 50S from the North Perth Survey (GA reference GA-0332).

  • The Marine Survey Multibeam Bathymetry Web Map Service contains the highest-resolution multibeam bathymetry grids available for download on Geoscience Australia's website. These bathymetry grids were collected over numerous multibeam survey programs conducted in Australian mainland and Antarctic waters by both Geoscience Australia and our collaborators. Layers are grouped by survey or region and where available include both the Geoscience Australia and vessel survey identification numbers that contributed to the bathymetry grids. Bathymetry grids have been rendered over a rainbow colour-ramp with minimum and maximum depth values unique for each survey. These values are specified in each survey's layer description. The resolution of each bathymetry grid is also specified in each survey's layer description

  • This web service combines two surveys GA-4415 and GA-0348. The Casey Station Bathymetry survey displays one seamless bathymetry grid of 1m resolution. Further details of the data lineage can be found with the associated database. This web service is published with the permission of the CEO, Geoscience Australia.

  • This web service combines two surveys GA-4415 and GA-0348. The Casey Station Bathymetry survey displays one seamless bathymetry grid of 1m resolution. Further details of the data lineage can be found with the associated database. This web service is published with the permission of the CEO, Geoscience Australia.

  • <p>Australia has established a network of 58 marine parks within Commonwealth waters covering a total of 3.3 million square kilometres, or 40 per cent of our exclusive economic zone (excluding Australian Antarctic Territory). These parks span a range of settings, from near coastal and shelf habitats to abyssal plains. Parks Australia manages the park network through management plans that came into effect for all parks on 1 July 2018. Geoscience Australia is contributing to their management by collating and interpreting existing environmental data, and through the collection of new marine data. “Eco-narrative” documents are being developed for those parks, where sufficient information is available, delivering collations and interpretations of seafloor geomorphology, oceanography and ecology. Many of these interpretations rely on bathymetric grids and their derived products, including those in this data release. <p>Geoscience Australia has developed a new marine seafloor classification scheme, which uses the two-part seafloor mapping morphology approach of Dove et al (2016). This new scheme is semi-hierarchical and the first step divides the slope of the seafloor into three Morphological Surface categories (Plain, <2°; Slope, 2-10°; Escarpment, >10°). This classification was applied to the portion of the Beaman and Spinnocia (2018) 30 m grid within the Kimberley Marine Park. <p>This research is supported by the National Environmental Research Program Marine Biodiversity Hub through Project D1. <p>Beaman, R.J. and Spinoccia, M. (2018). High-resolution depth model for Northern Australia - 30 m. Geoscience Australia. <p>Dove, D., Bradwell, T., Carter, G., Cotterill, C., Gafeira, J., Green, S., Krabbendam, M., Mellet, C., Stevenson, A., Stewart, H., Westhead, K., Scott, G., Guinan, J., Judge, M. Monteys, X., Elvenes, S., Baeten, N., Dolan, M., Thorsnes, T., Bjarnadóttir, L., Ottesen, D. (2016). Seabed geomorphology: a twopart classification system. British Geological Survey, Open Report OR/16/001. 13 pages.

  • As part of the Australian Government's "New Oil" initiative, Geoscience Australia undertook a geophysical survey (the Southwest Frontiers Survey) of the south-western Australian continental margin in late 2004. The survey acquired 2700 km of industry-standard, 106-fold seismic data recorded to 12 seconds two-way time using a 6-8 km digital streamer and 4900 cui gun array. Marine reflection seismic acquisition was supplemented by recording of refraction seismic data by sonobuoys at sea and by land stations in the onshore/offshore observation scheme. Marine reflection survey shots were used as sources of seismic energy for both add-ons. The main scientific objectives of refraction work were: 1. Provide accurate seismic velocity information to improve depth conversion of reflection seismic data and to define type of basement and crust below it underneath the sedimentary basins. 2. Provide estimates of crustal thickness underneath major sediment deposition centres in the area to better constrain interpretation of tectonic evolution of the region. The new refraction seismic data have substantially supplemented coverage of the area resulting from old sonobuoy work and from very few onshore stations. When applied to a basement travel time pick interpreted in the multi-channel reflection data set, the new velocity data indicate a maximum sediment thickness in excess of 9 km. A comparison of stacking velocities and modelled sonobuoy data suggests that, unlike in other areas, stacking velocities from the Bremer Sub-basin survey 280 can be used as a reliable substitute for acoustic velocities down to 3 s two-way time into the sediments, for the purpose of calculating sediment thickness. One of the key findings of the refraction seismic study is that velocities in the basement are generally in the 5.2-5.6 km/s range, indicating that, contrary to priory expectations, basement in the area is mostly not granitic in composition. Results from the Bremer area conjugate counterpart in Antarctica obtained by the 50th Russian Antarctic Expedition (December 2004 - April 2005) also show low velocities in the basement on the inner side of Antarctic continent-ocean boundary, and therefore are consistent with our results from the Australian margin. If we combine all results available to us, it appears that a ~400km wide zone in Gondwana prior to break-up had basement velocities significantly lower than normal continental values of 6.0 - 6.2 km/s typical for granites and gneisses. The presence of low grade metasediments of the Albany-Fraser Province and its Antarctic equivalent is our preferred interpretation of this observation. Metasediments produce substantially less heat than granites and this leads to a different scenario, than granitic basement, for hydrocarbon maturation in the Bremer sub-basin, which is one of the targets of Geoscience Australia's Big New Oil program. Advanced burial and thermal geo-history modelling in this area was carried out for the first time in Australia without relying on default values (such as Heatflow or geothermal gradient) in modelling packages. Results of this work will be presented at the APPEA 2006 Conference. The similarities in seismic properties of the crust between the Bremer/Recherche area on the SW Australian continental margin and its conjugate on the Antarctic margin, has generated interest in Russia. As a result, planning of Russian Antarctic Expedition 51 (to start in December 2005) will take into consideration the need to record additional data at specific locations to answer questions of interest to both Australia and Russia.

  • This report is the first of three reports that provide the scientific analyses and interpretations resulting from a four-year collaborative habitat mapping program undertaken within the Darwin and Bynoe Harbour region by Geoscience Australia (GA), the Australian Institute of Marine Science (AIMS) and the Northern Territory Government Department of Environment and Natural Resources (DENR). This 4 year program (2014-2018) aims to improve knowledge of the marine environments in the Darwin and Bynoe Harbour regions by collating and collecting baseline information and developing thematic habitat maps that will underpin future marine resource management decisions. This program was made possible through offset funds provided by the INPEX-operated Ichthys LNG Project to DENR, and co-investments from GA and AIMS.

  • Microalgal blooms are one of the most visible responses to anthropogenic nutrient loadings in coastal ecosystems. However, differentiating sources of nutrients causing blooms remains a challenge. The response of phytoplankton and benthic microalgae (BMA) to nutrient loads was compared across tidal creeks with and without secondary treated sewage in a tropical estuary. Concentrations of the sewage marker, coprostanol, were higher near sewage discharge points and decreased downstream. This was commensurate with a decline in nitrogen and phosphorus concentrations suggesting that sewage was the main source of nitrogen and phosphorus. Primary productivity in the water column was limited by nitrogen availability in absence of sewage, with nitrogen saturation in the presence of sewage. Phytoplankton primary productivity rates and chlorophyll a concentrations increased in response to sewage, and there was a greater response than for BMA. There was no evidence of a change in algal pigment proportions within the phytoplankton or BMA communities. This study highlights the scale and type of response of algal communities to sewage nutrients in situ.

  • Geoscience Australia is providing extensive advice, expertise and support to the Australian Transport Safety Bureau (ATSB). The ATSB is leading a seabed mapping and underwater search for missing Malaysia Airlines flight 370 in the southern Indian Ocean. Bathymetry is the study and mapping of the sea floor. It involves obtaining measurements of the depth of the ocean and is equivalent to mapping on land. Before the underwater search for MH370 could begin, it was necessary to accurately map the sea floor to ensure that the search is undertaken safely and effectively. Bathymetry survey vessels spent months at sea, scanning the sea floor with multibeam sonar to gather detailed, high-resolution data. The data has revealed many seabed features for the first time. This computer-animated 'flythrough' shows a visualisation of some of the sea floor terrain in the search area.