Metadata record for data from ASAC Project 1117 See the link below for public details on this project. ---- Public Summary from Project ---- The aim of this project is to determine how feasible it is to regularly sample the pelagic under-ice community during winter at a coastal site near Mawson. Very few attempts have been made to sample the water column under the ice during the winter months and the processes that occur during this period remain critical gaps in our knowledge of the Antarctic marine ecosystem. ------------------------------------- The pelagic community under the Mawson sea ice was sampled during the winter of 2001 using 'light trap' sampling devices. The 'light traps' were tested at various depths in a range of configurations to determine whether they were an appropriate instrument to sample the winter pelagic community under the ice. Fourteen successful deployments of the light traps were made on seven separate occasions from 12 June to 12 September 2001. The light traps were deployed at three different depths - the underside of the sea ice, mid water, and just above the sea floor. Two different light sources were used to attract the animals, namely fluorescent tubes and cyalume sticks. Two different configurations of the traps were tested to retain the animals inside the trap - one with plastic flaps to trap the animals, the other with no flaps, allowing the animals to move freely inside the trap. The light traps were deployed and retrieved during darkness to avoid any influence of ambient light. The objectives of the project were met and it is assessed that the pelagic community in winter can be effectively sampled using this methodology. A result of particular interest is the success of the traps in capturing Pleuragramma antarctica, a species which has proven difficult to capture using traditional sampling methods such as nets.

Zooplankton were collected during the winter-spring transition during two cruises of the Aurora Australis: SIPEX in 2007 and SIPEX II in 2012. As part of the collections sea ice cores were collected to describe the ice habitat during the period of zooplankton collections. Ice cores were taken with a 20 cm diameter SIPRE corer and sectioned in the field with an ice core. Temperature was measured in the section using a spike thermometer and slivers of each section were melted without filtered water to record salinity. The remainders of each section were melted at 4oC in filtered seawater and the melted water was used to measure chlorophyll a concentration, and meiofauna species and abundance. Meiofauna were counted and identified using a Leica M12 microscope: to species in most cases and down to stage during 2012.

During RV Polarstern voyage PS117, under-ice observations were conducted with an instrumented Remotely Operated Vehicle (ROV) deployed directly from the ship. Collected time-stamped datastreams from the instrumented ROV include: ROV navigation data (heading, pitch, roll, position from an acoustic transponder system), under-ice video footage from the ROV camera and additional upward-looking video cameras, data from an upward-looking acoustic altimeter with integrated depth sensor (to measure the distance of the ROV to the sea-ice subsurface), under-ice hyperspectral irradiance and radiance data from two upward-looking radiometers, and time-stamped up-ward looking digital stills images to detect and quantify the abundance of herbivores at the ice-water interface. Methods for data collection are broadly consistent with methods described in detail in the referenced publication.

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.

Despite being a ubiquitous and abundant component of the Southern Ocean ecosystem, pack-ice seals (crabeater, Ross and leopard seals) are notoriously difficult to census as they are sparsely distributed over large regions of remote pack-ice. Historically, population censuses have been made from ship- or helicopter-based surveys, which are expensive and logistically difficult, and this inevitably leads to data which are limited, in time and space. High resolution images allow us now to accurately census seals e.g. elephant and Weddell seals at unprecedented spatial and temporal scales. Using this technology promises to provide regular estimates of the numbers of pack-ice seals in important regions such as Prydz Bay This study will develop techniques to survey pack-ice seals from high resolution satellite images, including automatic detection functions and a preliminary habitat model based on the characteristics of the ice contained in the images.

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.

Skin temperature data over the East Antarctic pack ice zone were recorded by the RAPPLS airborne instrument package using a KT-19II infrared pyrometer. The KT-19II infrared pyrometer was manufactured by heitronics, and sees a spectrum of 8-12um. IR and location data were logged to a Windows PC using a serial port logger developed by AAD science technical support. Due to some logging issues, substantial post-processing work was done by the AAD sea ice science group to ensure that recorded temperatures were correctly geolocated. Skin temperature data were not collected on two flights: Alpha [12 September 2007] and Foxtrot [14 September 2007] On two further flights, data were collected but the raw log files were so badly munged that we could not confidently tie locations to temperatures. These were: Tango [30 September 2007] and Uniform [1 October 2007] The data are presented in .csv files for each flight showing time and date. lat, lon, recorded temp [deg K], temp converted to C. To visualise the data, .kmz files that can be viewed in Google Earth or NASA's worldwind virtual globes are provided, one for each flight. Skin temperature is represented by a coloured dot at each measurement point. Clicking on each poijt will show its location and recorded temperature. The description field of each .kmz file provides a colour scale.

Project 565: The database provides a list of species of ciliates and testate amoebae (Protozoa: Ciliophora; Testacea) recorded in various edaphic habitats, e.g., mineral soils (fellfield), ornithogenic soils, terrestrial mosses, from ice-free coastal areas and inshore islands in the area of Casey Station, Wilkes Land, coastal continental Antarctica. 26 ciliate (9 first records for continental Antarctica, 1 undescribed) and 5 testacean species (3 new records) were found. Sea ice study (Weddell Sea): The ciliate biodivesity was studied in several types of sea ice (mainly young pancake ice) from the Weddell Sea, Antarctica, in the austral autumn 1992 (March-May) during the cruise ANT X/3 of RV Polarstern. 49 ciliate species were predominantly found in sea ice and 6 spp. in the pelagial; 20 of these were new to science. A word document containing a list of species that were recorded as part of the project is available for download from the provided URL. These data have also been incorporated into the biodiversity database.

A report completed as part of this project is available for download from the URL given below. Extracts of the report are presented in the metadata record. See the report for full details. Several species of Antarctic fish were collected from the shallow waters off Davis Station during the 2000-01 season as part of a study examining the properties of 'antifreeze' proteins contained within the blood of these animals. Fish were sampled at regular intervals from a range of depths and various sites near the station. The main objectives of the study were to collect serum and selected tissues from Nototheniid (cod) and Channichthyid (ice fish) species. Over 170 fish were collected throughout the calendar year. Samples were taken as required, processed and the fish preserved for further analysis on return to Australia. In Australia the serum will be tested for special antifreeze molecules that allow these animals to live in water that is colder than the usual freezing point of their body fluids. Such molecules, once identified, may be synthesised in a laboratory, and have numerous potential practical applications, from the preservation of frozen foods, to preservation of blood plasma and organs for human transplant. Analyses of this nature will be undertaken at the University of Sydney.

ASPeCt is an expert group on multi-disciplinary Antarctic sea ice zone research within the SCAR Physical Sciences program. Established in 1996, ASPeCt has the key objective of improving our understanding of the Antarctic sea ice zone through focussed and ongoing field programs, remote sensing and numerical modelling. The program is designed to complement, and contribute to, other international science programs in Antarctica as well as existing and proposed research programs within national Antarctic programs. ASPeCt also includes a component of data rescue of valuable historical sea ice zone information. The overall aim of ASPeCt is to understand and model the role of Antarctic sea ice in the coupled atmosphere-ice-ocean system. This requires an understanding of key processes, and the determination of physical, chemical, and biological properties of the sea ice zone. These are addressed by objectives which are: 1) To establish the distribution of the basic physical properties of sea ice that are important to air-sea interaction and to biological processes within the Antarctic sea-ice zone (ice and snow cover thickness distributions; structural, chemical and thermal properties of the snow and ice; upper ocean hydrography; floe size and lead distribution). These data are required to derive forcing and validation fields for climate models and to determine factors controlling the biology and ecology of the sea ice-associated biota. 2) To understand the key sea-ice zone processes necessary for improved parameterization of these processes in coupled models. These ASPeCt measurements were taken onboard the Aurora Australis during the SIPEX voyage in the 2007-2008 summer season.