Metadata record for data from ASAC Project 1242 See the link below for public details on this project. ---- Public Summary from Project ---- This project will undertake preliminary assessment of Southern Ocean squid stocks. Squids will be collected by jigging and light trapping off research vessels in the region of Macquarie Island and other selected locations where the opportunity arises. Little is known about squid biology in the Pacific and Indian sectors of the Southern Ocean. This project will help to provide initial basic biological data on the squid species present. 18 squid we caught on-board the Aurora Australis in November, 2001. All were caught 200-300 kms south of Tasmania, by a hand-held squid jig, at latitude 47 South at a depth of 1m. All samples caught on the 5/11/01 have the code QA/AA/80/01. There was no code written for others caught on 3/11/01. The fields in this dataset are: Species Date Mantle length (mm) Weight (g) Sex Maturity Gonad weight (g) See also the metadata record for ASAC project 1340 (ASAC_1340), Squid in the antarctic and subantarctic, their biology and ecology.

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.

---- Public Summary from Project ---- The lakes and fjords of the Vestfold Hills region of Antarctica provide unique ecosystems for studying environmental changes in Antarctica over the past 8000 years. Studies of the changes in organic matter composition in sediment cores provide information how the microbial and plankton communities have changed over time in response to varying chemical and physical conditions. Our study will provide new information about how the cycles of the biologically-important elements carbon and sulfur are linked and why some sediments can preserve large amounts of organic carbon. This information will be useful for studies of palaeoclimate and will also provide valuable insights into the processes that produce petroleum source rocks. From the abstracts of the referenced papers: Preserved ribosomal DNA of planktonic phototrophic algae was recovered from Holocene anoxic sediments of Ace Lake (Antarctica), and the ancient community members were identified based on comparative sequence analysis. The similar concentration profiles of DNA of haptophytes and their traditional lipid biomarkers (alkenones and alkenoates) revealed that fossil rDNA also served as quantitative biomarkers in this environment. The DNA data clearly revealed the presence of six novel phylotypes related to known alkenone and alkenoate-biosynthesising haptophytes with Isochrysis galbana UIO 102 as their closest relative. The relative abundance of these phylotypes changed as the lake chemistry, particularly salinity, evolved over time. Changes in the alkenone distributions reflect these population changes rather than a physiological response to salinity by a single halophyte. Using this novel palaeo-ecological approach of combining data from lipid biomarkers and preserved DNA, we showed that the post-glacial development of Ace Lake from freshwater basin to marine inlet and the present-day lacustrine saline system caused major qualitative and quantitative changes in the biodiversity of the planktonic populations over time. Post-glacial Ace Lake (Vestfold Hills, Antarctica), which was initially a freshwater lake and then an open marine system, is currently a meromictic basin with anoxic, sulfidic and methane-saturated bottom waters. Lipid and 16S ribosomal RNA gene stratigraphy of up to 10,400-year-old sediment core samples from the lake revealed that these environmentally induced chemical and physical changes caused clear shifts in the species composition of archaea and aerobic methanotrophic bacteria. The combined presence of lipids specific for methanogenic archaea and molecular remains of aerobic methanotrophic bacteria (13C-depleted delta8(14)-sterols and 16S rRNA genes) revealed that an active methane cycle occurred in Ace Lake during the last 3000 calendar years and that the extant methanotrophs were most likely introduced when it became a marine inlet (9400 y BP); rDNA sequences showed 100% sequence similarity with Methanosarcinales species from freshwater environments and were the source of sn-2- and sn3-hydroxyarchaeols. Archaeal phylotypes related to uncultivated Archaea associated with various marine environments were recovered from the present-day anoxic water column and sediments deposited during the meromictic and marine period.