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  • Eyre Offshore Resource Map Series 1:1m

  • This dataset contains species identifications of sponges collected during survey SOL4934 (R.V. Solander, 27 August - 24 September, 2009). Animals were collected from the Joseph Bonaparte Gulf with a benthic sled. Specimens were lodged at Northern Territory Museum on the 26 September 2009. Species-level identifications were undertaken by Belinda Glasby at the Northern Territory Museum and were delivered to Geoscience Australia on the 23 February 2011. See GA Record 2010/09 for further details on survey methods and specimen acquisition. Data is presented here exactly as delivered by the taxonomist, and Geoscience Australia is unable to verify the accuracy of the taxonomic identifications.

  • 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. The "challenger" folder contains processed multibeam backscatter data of the South East Tasmania Shelf. The SIMRAD EM3002 multibeam backscatter data were processed using the CMST_GA MB Process, a multibeam processing toolbox codeveloped by Geoscience Australia and Curtin University of Technology.

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  • This dataset contains the sea surface temperature data derived from the MODIS Terra sensor, the chlorophyll data derived from the SeaWIFS satellite, and the K490 data derived from the SeaWIFS satellite. Ocean temperature is a useful indicator of the type of marine life that could be found at a particular location. Many marine plants and organisms have a relatively narrow range of tolerance for temperature, and will either perish or be out-competed where temperatures are outside their comfort zone. Chlorophyll a is a plant pigment which provides a measurement of the biomass (or quantity) of plants. In the water column, it is a measure of the suspended (or planktonic) biomass of single-celled microscopic plants. Chlorophyll is a commonly used measure of water quality. K490 indicates the turbidity of the water column; the depth to which the visible light in the blue-green region of the spectrum penetrates the water column. It is directly related to the presence of particles in the water column. Turbidity has consequences for benthic marine life, ranging from the availability of light to the quantity of nutrients in the water column. The datasets contain 6 grids. Two for each variable: mean and standard deviation. Please see the metadata for detailed information.

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  • The Leeuwin Current has significant ecological impact on the coastal and marine ecosystem of south-western Australia. This study investigated the spatial and temporal dynamics of the Leeuwin Current using monthly MODIS SST dataset between July 2002 and December 2012. Topographic Position Index layers were derived from the SST data for the mapping of the spatial structure of the Leeuwin Current. The semi-automatic classification process involves segmentation, 'seeds' growing and manual editing. The mapping results enabled us to quantitatively examine the current's spatial and temporal dynamics in structure, strength, cross-shelf movement and chlorophyll a characteristic. It was found that the Leeuwin Current exhibits complex spatial structure, with a number of meanders, offshoots and eddies developed from the current core along its flowing path. The Leeuwin Current has a clear seasonal cycle. During austral winter, the current locates closer to the coast (near shelf break), becomes stronger in strength and has higher chlorophyll a concentrations. While, during austral summer, the current moves offshore, reduces its strength and chlorophyll a concentrations. The Leeuwin Current also has notable inter-annual variation due to ENSO events. In El Niño years the current is likely to reduce strength, move further inshore and increase its chlorophyll a concentrations. The opposite occurs during the La Niña years. In addition, this study also demonstrated that the Leeuwin Current has a significantly positive influence over the regional nutrient characteristics during the winter and autumn seasons.