Summary: | Progress Code: completed Statement: See the report available for download for further information. From February to March 2010, Geoscience Australia (GA) conducted a multibeam sonar survey of the coastal waters of the Vestfold Hills in the Australian Antarctic Territory. The survey was conducted jointly with Australian Antarctic Division (AAD) and the Deployable Geospatial Survey Team (DGST) of the Royal Australian Navy. The survey was aimed primarily at understanding the character of the sea floor around Davis Station to better inform studies of the benthic biota and the possible impacts of the Davis sewage outfall. DGST were involved to ensure that the bathymetric data could be used to update and extend the nautical charts of the Davis area. The survey was conducted using GA's Kongsberg EM3002D multibeam echo sounder and C-Nav Differential GPS system mounted on the AAD work boat Howard Burton. Sixteen under water videos were also collected using the GA Raytech camera system and 3 grabs were also collected to compliment an intensive sampling program by AAD divers and a sampling program conducted in the 1990's by University of Tasmania (Franklin, 1996). An area of 42 km2 was surveyed intensively immediately off Davis and additional survey lines were run to Long Fjord in the north and to Crooked Fjord and the Sorsdal Glacier in the south. The main survey area had between 150% and 200% coverage as the seabed was esonified from opposing angles to resolve and provide detail to the numerous features of the seafloor such as rocky reefs, iceberg scours, boulders, anchor chain drag marks and grounded icebergs. The new high resolution data provided detailed maps of sea bed morphology and texture classification to complement sample data. Sixteen video transects were collected and 3 grab samples collected in water too deep for the Australian Antarctic Division Diving program. New high resolution bathymetric grids have been prepared for scientific use and further processing for hydrographic charting is ongoing. A new ...
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