Bathymetric Contours and height range polygons of approaches to Davis Station, derived from RAN Fair sheet, Aurora Australis and GEBCO soundings.

Royal Australian Navy soundings of approaches to Davis Station. This fair sheet, HI 171 V5/519-6877/91 scale 1:5000, was hand digitised to capture soundings as point data. The data are not suitable for navigation. Bathymetric contours derived from these and other soundings are available from the metadata record with ID davisbathy_gis.

Royal Australian Navy soundings of approaches to Davis Station. This fair sheet, HI 120 SUP 1 V5/480-6877/7 scale 1:10 000, was hand digitised to capture soundings as point data. The data are not suitable for navigation. Bathymetric contours derived from these and other soundings are available from the metadata record with ID davisbathy_gis.

Dimethylsulfide and its precursors and derivatives constitute a major sulfate aerosol source. This dataset incorporates the potential for increased UV radiation effects due to stratospheric ozone depletion over spring and summer in Antarctica, using large-scale incubation systems and 13-14 day incubation periods. Surface seawater (200 micron filtered) from the Davis coastal embayment was incubated during four experiments over the 2002-03 Antarctic Summer. The data incorporates seawater measurements of DMS, DMSP and DMSO over a temporal progression during each incubation experiment. Six polyethylene tanks of varying PAR and UV irradiances were incubated. Water was collected stored and analysed by gas chromatography according to a specific sampling protocol, employed by all investigators associated with the project. The data are organised according to analysis day, with each days calibration data displayed at the top of each sheet. The sample code is followed by GC run number and then the raw count data from the GC. This is calculated to nanomoles DMS, DMSP or DMSO. Sample Codes: Codes for temporal data follow format X.XXXX 1st X gives experiment number, 1 to 4. 2nd X gives sampling day, 0, 0.5, 1, 2, 4, 7, 14 (will result in digit code for day no. less than 10 3rd X gives tank number relating to irradiance level(one to six) 4th and 5th X is replicate number, (01, 02, 03, DMS), (04, 05,06, DMSP total), (07, 08, 09, DMSP dissolved), (10, 11, 12, DMSO total). The fields in this dataset are: Sample Code Run Number from the GC Counts - GC generated raw data Log Counts - logarithmic conversion of the count data Log -c - logarithmic conversion minus the y-intercept determined by calibration of the GC. (log -c)/m - log -c divided by m, determined by calibration of the GC. ngS anti log - nanograms of Sulfur NaOH - NaOH adjustment ngS/L - adjustment per litre nM-DMSP/L - nanoMol's DMSP per litre nm-DMS/L - nanoMol's DMS per litre September 2013 Update: DMSO was analysed in these experiments according to an adaptation of the sodium borohydride (NaBH4) reduction method of Andreae (1980). The method has since been superseded and the data here probably displays inaccuracies as a result of the analytical method used. This DMSO data should be treated with caution.

Royal Australian Navy soundings of approaches to Davis Station. This fair sheet, HI 120 V5/463-6877/1 scale 1:10 000, was hand digitised to capture soundings as point data. The data are not suitable for navigation. Bathymetric contours derived from these and other soundings are available from the metadata record with ID davisbathy_gis.

This dataset contains data on the habitats, distribution and numbers of Adelie Penguins (Pygoscellis adeliae) along the Vestfold Hills coast (including colonies on the mainland and offshore islands) during November 1973. The data are obtained from counts at the colonies and black and white photographs. Some aerial photographs were taken at Davis in 1981-82 and 1987-88, and will be compared to the results of this survey. The results are listed in the documentation. A total of 174178 26127 breeding pairs were counted. An increase in Adelie penguin population was found at most locations in East Antarctica. Data from this record has been incorporated into a larger Adelie penguin dataset described by the metadata record - Annual population counts at selected Adelie Penguin colonies within the AAT (SOE_seabird_candidate_sp_AP). It also falls under ASAC project 1219 (ASAC_1219).

From the abstract of the attached paper: Underwater calling behaviour between breathing bouts of a single adult male Weddell seal (Leptonychotes weddellii) was examined with respect to call type and timing late in the breeding season at Davis Station, Antarctica. Underwater calls and breathing sounds were recorded on 1 and 8 December 1997. Thirty-seven sequences of calls prior to surfacing to breathe and 36 post-submerging sets of calls were analysed with respect to probability of call type occurrence and timing. Dives were 461 plus or minus 259 seconds (mean plus or minus standard deviation). The seal called every 29.7 plus or minus 56.2 seconds throughout a dive. The first call after submerging was usually (n = 29 of 36) a low frequency (less than 0.8 kHz) growl. Three patterns of three- to five-call type sequences were made following 28 of 36 breathing bouts. Call type patterns after submerging exhibited fewer different sequences than those before surfacing (chi-squared = 61.42, DF = 4, p less than 0.000001). The call usage patterns before surfacing were diverse and did not indicate when the seal was going to surface, a time when he would be vulnerable to attack from below. Our findings suggest the hypotheses that territorial male Weddell seals call throughout each dive and use stereotyped call patterns to identify themselves while vocally asserting dominance. This work was completed as part of ASAC project 2122 (ASAC_2122). The fields in this dataset are: Tape number Sequence per tape Sequence entire data Call types Count since last breath Last breathing bout number Count prior to next breath Time in tape (seconds) End time of last breath Start time of next breath Time since dive The 'sequence' relates to the sequence of call types that are given between the end of the last breath of a breathing bout and the beginning of the first breath the next time the seal surfaces to breathe. Essentially the report relates to the stereotyped nature of the call types, especially just after the dominant male dives after finishing breathing. Each time the animal surfaced, that was identified as a breathing bout. They are numbered sequentially. At the very start of the data set the seal had to surface before the breathing bout could be counted (as number 1). This procedure enabled us to identify the order and timing of the calls that occurred immediately before and immediately after each breathing bout. Thus, the 'count prior to the next breath' gives the order of the calls before the seal surfaced to breathe again (third last, second last, last,). The call types were analysed with respect to the following pattern: third last, second last, last, breathing bout, first, second, third, etc. to third last, second last, last, next breathing bout.

From the abstract of one of the papers: Oxygen microelectrodes were used to measure the photosynthetic rates of Antarctic fast ice algal mats. Using the oxygen flux across the diffusive boundary layer below the fast ice at Davis, a productivity range of 0-1.78mg C per square metre per hour was measured. This is at the lower end of fast ice productivity estimates and suggests that conventional carbon 14 techniques may overestimate sea ice algal mat productivity. Photosynthetic capacity (P max) approached 0.05 mg per C.(mg chlorophyl a) per hr. Onset of photosynthesis saturation, E k, was found at about 14 micromol photons per square metre per second. The irradiance of photoinhibition onset, E inh, was about 20 micromol photons per square metre per second and the irradiance at the compensation point, E c, was 4 micromol photons per square metre per second.

Possible communication between territorial male Weddell seals (Leptonychotes weddellii) under the ice with females on the ice was investigated. In-air and underwater recordings of underwater calls were made at three locations near Davis, Antarctica. Most underwater calls were not detectable in air, often because of wind noise. In-air call amplitudes of detectable calls ranged from 32-74 dB re. 20 microPa at 86 Hz down to 4-38 dB re. 20 microPa at 3.6 kHz. Most of these would be audible to humans. Only 26 of 582 amplitude measurements (from 230 calls) ranged from 5 dB to a maximum of 15 dB above the minimum harbour-seal (Phoca vitulina) in-air detection threshold. Seals on the ice could likely hear a few very loud underwater calls but only if the caller was nearby and there were no wind noises. The low detectability of underwater calls in air likely precludes effective communication between underwater seals and those on the ice. See other metadata records and datasets associated with ASAC project 2122 (ASAC_2122) for further information. The fields in this dataset are: Column A: G = grunt, T = trill, CT = constant freq. trill, O = tone, C = chug, AW = ascending whistle, DW = descending whistle, L = growl, R - roar Column B: frequency (Hz) Column C: underwater call level NOTE dB re 20 uPa Column D: in-air call level dB re 20 uPa Column E: in-air background noise level at this frequency dB re 20 uPa Column F: water - air difference dB Column G: location, 1-3, see paper for code Column H: seal in-air threshold dB re 20 uPa Column I: human in-air threshold dB re 20 uPa Column J: seal in-air threshold at this frequency dB re 20 uPa

Many vocalisations produced by Weddell seals (Leptonychotes weddellii) are made up of repeated individual distinct sounds (elements). Patterning of multiple element calls was examined during the breeding season at Casey and Davis, Antarctica. Element and interval durations were measured from 405 calls all greater than 3 elements in length. The duration of the calls (22 plus or minus 16.6s) did not seem to vary with an increasing number of elements (F4.404 = 1.83, p = 0.122) because element and interval durations decreased as the number of elements within a call increased. Underwater vocalisations showed seven distinct timing patterns of increasing, decreasing, or constant element and interval durations throughout the calls. One call type occurred with six rhythm patterns, although the majority exhibited only two rhythms. Some call types also displayed steady frequency changes as they progressed. Weddell seal multiple element calls are rhythmically repeated and thus the durations of the elements and intervals within a call occur in a regular manner. Rhythmical repetition used during vocal communication likely enhances the probability of a call being detected and has important implications for the extent to which the seals can successfully transmit information over long distances and during times of high level background noise. See other metadata records and datasets associated with ASAC project 2122 (ASAC_2122) for further information. The fields in this dataset are: Tape/Site/File Filename Call Type Total Number of Elements Attribute Frequency Time Casey Davis