The RAN Australian Hydrographic Service conducted hydrographic survey HI468 at Davis, January to March 2010. The survey was conducted jointly with Geoscience Australia and the Australian Antarctic Division. The main survey area was near Davis but additional survey lines were followed to Long Fjord to the north and to Crooked Fjord and the Sorsdal Glacier in the south. The survey dataset, which includes the Report of Survey, was provided to the Australian Antarctic Data Centre by the Australian Hydrographic Office and is available from the Australian Antarctic Data Centre by request. The RAN Australian Hydrographic Service team was lead by LCDR R.D.Bowden. The data are not suitable for navigation. Geoscience Australia produced bathymetric and backscatter gridded datasets from the survey data which are available via the metadata record 'Coastal seabed mapping survey, Vestfold Hills, Antarctica, February-March 2010' with Entry ID: Davis_multibeam_grids. The Australian Antarctic Division produced two bathymetric maps from the survey data. See Related URLs in this metadata record.

The date are of the highest amplitudes across the frequency range of Weddell seal tonal trills (an underwater call made by males). Each column presents the results of a frequency amplitude measure that is relative to the highest amplitude of that trill, independent of the frequency at which that amplitude occurs. This removes the influence of the overall amplitude of the call which is influence of the distance the sea was from the hydrophone when the recording was made. Four trill patterns were identified (A - D) and a number of trills not included in the analyses are classed as type X. The X call types were excluded because the original recording was later found to be overloaded or partly masked by ice noises or the calls of another seal. Analysis details are included in the accompanying manuscript. The accompanying Excel file contain the frequency amplitude measurements of individual trills at two location groups: the Aurora Truning location at the anchorage location of the Aurora Australis near Davis and the other group is a number of breeding groups in the Vestfold Hills. Variable A is the frequency in Hz, Variables B to DH at the Aurora Turning location and B to BY at the Davis locations are data from individual trills. Rows 2 or 3 indicate the four Trill patterns, A, B, C or D, with an X designation for trills that were not included in the analyses due to limited frequency ranges or overloading of the original recordings (that was discovered later in the analyses). ssize or samplesize is the number of trills that were at each frequency bin.

Crustaceans are an important component of the Antarctic marine ecosystem. Large numbers live in or close to the sea-ice cover, using it as a refuge from predation and a source of food. However, the impact of these animals on algae that grows in the sea ice is unknown. This study is examining the diets and grazing rates of crustaceans in the Antarctic sea-ice ecosystem. These results will aid our understanding of the fate of algal production in sea-ice and will enable the construction of realistic carbon budgets for this ecosystem. This project was commenced in July 2002. A five-week voyage was undertaken on the RV Aurora Australis in October and November 2002, in the vicinity of the Mertz Glacier. Pack ice cores and sub-ice water samples were collected from 8 locations, with 3 to 5 samples of each type collected per site. The cores were sectioned in the field, melted and treated for further analysis. All samples were either preserved or frozen, depending on future requirements, and returned to Australia. Sea ice cores were processed for a range of analyses including microscopy, lipid class and fatty acid determination and stable isotope analysis. A physical description of the pack ice environment (ice type, ice thickness, snow cover, temperature profiles, salinity profiles) was also compiled. A second sampling of the pack ice occurred in Sept-Oct 2003. To date, the salinity and temperature profiles of the pack ice cores have been described and a database compiled of the physical description of the region. A large number of samples (10 sites; 5 ice/water/animal samples per site) was collected and analysis has begun of stable isotopic signatures, fatty acids, chlorophyll a and species identifications. Crustaceans have been sorted under the microscope and initial descriptions of gut contents begun. The third successful sampling trip was to the fast ice surrounding Davis Station during the 2003/04 summer. Two sites were sampled regularly, with a full suite of analyses undertaken. This will provide a temporal component to the project to complement the spatial approach used in the pack ice. Analysis of the fast ice samples is ongoing. Two more sampling trips were carried out during the 2004/05 season. The first in the pack ice offshore from Casey and the second in the fast ice at Casey. The same suite of analyses as listed above was carried out and analyses are ongoing. The download file contains five excel spreadsheets, as well as a word document which further explains data collection.