From 1 - 10 / 855
  • Deep-water demersal fishes are an important component of continental shelf and slope ecosystems and play an important role in the economies of many countries. Strong and predictable relationships of fishes with seabed habitats, in conjunction with rapid advances in acoustic seabed mapping capabilities, indicate there is great potential for using habitats as proxies or ‘surrogates’ to predict species distribution and abundance patterns at broad regional scales. However, few studies have evaluated this potential in complex seabed environments. In this study, we examined the spatial distributions, assemblage composition, and benthic habitat associations of deep-water demersal fish species over three spatial scales across Cordell Bank, a deep-water bank in central California. Demersal fishes were counted and habitats quantified from 60 strip-transects allocated over the extent of the bank using in situ observer and video-recorded data from the two-person Delta submersible. Both abundance and distribution of demersal fish species on Cordell Bank were strongly correlated with spatial location and habitat composition on the bank. Habitat structure was heterogeneous at several spatial scales. At broad scales, the rocky bank itself contained the highest diversity of both habitats and fishes. At intermediate scales, transition zones (10-100s of m wide) between the bank and continental slope and shelf sediments supported a diverse and characteristic suite of fish species. Habitats were also heterogeneous at finer-scales (1-10s of m) within these broad-scale zones, and fish responses to these habitat characteristics were taxon-specific, and often contingent on the spatial configuration of fine scale habitats within the broader-scale landscape. The results of this study indicate that for many species it is not sufficient to just know the fine-scale habitat association to predict fish assemblages.

  • A laboratory study has been conducted to determine the best methods for the detection of C10 to C40 hydrocarbons at naturally occurring oil seeps in marine sediments. The results indicate that a commercially available method using hexane to extract sediments and gas chromatography to screen the resulting extract is effective at recognizing the presence of migrated hydrocarbons at concentrations between 50 to 5,000 ppm. When the oil charge is unbiodegraded the level of charge is effectively tracked by the sum of n-alkanes in the gas chromatogram. However, once the charge oil becomes biodegraded, with the loss of n-alkanes and isoprenoids, the level of charge is tracked by the quantification of the Unresolved Complex Mixture (UCM). The use of GC-MS was also found to be very effective for the recognition of petroleum related hydrocarbons and results indicate that GC-MS would be a very effective tool for screening samples at concentrations below 50 ppm oil charge.

  • The Gold Coast hydrologically enforced digital elevation model (DEM) was created from a combination of the following surveys; Redland 2009 LiDAR, Gold Coast 2009 LiDAR and Logan 2009 LiDAR survey areas. The data is licensed for use by all Commonwealth, State and Local Government. Data acquisition and post-processing for all of the input surveys has been controlled to achieve a fundamental vertical accuracy of <0.15m (RMS, 68% CI) and horizontal accuracy within 0.45 m. Horizontal coordinates are based upon Map Grid of Australia (MGA) Zone 56 projection. Vertical coordinates are referenced to Australian Height Datum (AHD). The hydrologically conditioned and drainage enforced 2m DEM or HDEM was developed in 2010 as part of the Urban DEM project managed by the CRC for Spatial Information and Geoscience Australia. The HDEM was produced by SKM using the ANUDEM program. The HDEM ensures that primary stream/channel flow, and water flow across the land surface are accurately represented. The hydrologically enforced elevation model should be used for hydrological modelling.

  • As part of the Australian Government's Onshore Energy Security Program and the Queensland Government's Smart Mining and Smart Exploration initiatives, deep seismic reflection surveys were conducted in North Queensland to establish the architecture and geodynamic framework of this area in 2006 (Mt Isa Survey; also involving OZ Minerals and pmd*CRC) and 2007 (Cloncurry-Georgetown-Charters Towers Survey; also involving AuScope). Nearly 2300 line km of seismic data were acquired during these surveys. Geochemical, geochronological and complementary geophysical studies were undertaken in support of the seismic acquisition. Overviews of the geology of North Queensland and more detailed descriptions and the results of these surveys are presented in Hutton et al. (2009a, b), Korsch et al. (2009a), Withnall et al. (2009a, b), Henderson and Withnall (2009), and Henderson et al. (2009). The purpose here is to use the new geodynamic insights inferred from these data to provide comments on the large-scale geodynamic controls on energy and other mineral potential in North Queensland. This contribution draws on geodynamic and metallogenic overviews presented by Korsch et al. (2009b) and Huston et al. (2009)

  • This report outlines the level survey completed during the visit to Betio Island, the Republic of Kiribati in February / March 2009. This is the third EDM Height Traversing levelling survey of the deep bench mark array in the Republic of Kiribati. The 2009 survey is a repeat survey. On nine previous occasions, from 1992 to 2004 the Kiribati level survey was performed by the National Tidal Centre (NTC) using the Precise Differential Levelling technique. This project is sponsored by the Australian Agency for International Development (AusAID), managed by the Bureau of Meteorology (BOM) and supported by the National Geospatial Reference Systems Project (NGRS), Geospatial Earth Monitoring Division, GEOSCIENCE AUSTRALIA.

  • This report outlines the level survey completed during the visit to Majuro Atoll, Marshall Islands during 27 March to 4 April, 2009. This is the third EDM Height Traversing levelling survey of the deep bench mark array in Majuro Atoll, Marshall Islands. This is a repeat survey. On eight previous occasions, from 1993 to February 2003, the Marshall Islands level survey was performed by the National Tidal Centre (NTC) using the Precise Differential Levelling technique. This project is sponsored by the Australian Agency for International Development (AusAID), managed by the Bureau of Meteorology (BOM) and supported by the National Geospatial Reference Systems Project (NGRS), Geospatial Earth Monitoring Division, GEOSCIENCE AUSTRALIA.

  • This report outlines the level survey completed during the visit to Manus Island, Papua New Guinea (PNG) from 8 - 12 June 2009. Precise Differential Levelling surveys were performed on previous occasions, from 1994 to 2003 by NTC and the survey in January 2006 was a comparison between the precise levelling and EDM height traversing technique. This is the third EDM Height Traversing levelling survey of the deep bench mark array in Manus Island, PNG. The previous levelling surveys using this technique were performed in January 2006 and August 2007. This project is sponsored by the Australian Agency for International Development (AusAID), managed by the Bureau of Meteorology (BOM) and supported by the National Geospatial Reference Systems Project (NGRS), Geospatial Earth Monitoring Division, GEOSCIENCE AUSTRALIA.

  • This report outlines the level survey completed during the visit to Honiara, Solomon Islands during 12 - 19 May 2009. Precise Differential Levelling surveys were performed on four previous occasions, from August 1994 to March 1999 by NTC. This is the second EDM Height Traversing levelling survey of the deep bench mark array in Honiara, Solomon Islands. The previous levelling survey was performed in August 2007 by Geoscience Australia and SOPAC. This project is sponsored by the Australian Agency for International Development (AusAID), managed by the Bureau of Meteorology (BOM) and supported by the National Geospatial Reference Systems Project (NGRS), Geospatial Earth Monitoring Division, GEOSCIENCE AUSTRALIA.

  • This report outlines the level survey completed during the visit to Funafuti, Tuvalu January 2009. This is the third EDM Height Traversing levelling survey of the deep bench mark array in Funafuti, Tuvalu. This is also a repeat survey and on eight previous occasions, from 1993 to 2003 the Tuvalu levelling survey was performed by the National Tidal Centre (NTC) using the Precise Differential Levelling technique. This project is sponsored by the Australian Agency for International Development (AusAID), managed by the Bureau of Meteorology (BOM) and supported by the National Geospatial Reference Systems Project (NGRS), Geospatial Earth Monitoring Division, GEOSCIENCE AUSTRALIA.