CONTINENT > ANTARCTICA > Larsemann Hills
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The distribution and abundance of ice-associated copepods in the fast ice of the Australian Antarctic Territory were investigated over a distance of approximately 650 km between October and December 1995. The six sites where collections were made were: offshore from Mawson station, Larsemann Hills (including Nella Bay), Rauer Islands (ice edge near Filla Is), O'Gorman Rocks and Bluff Island near Davis Station, and Murphy Rocks in the northern Vestfold Hills. Ice cores were obtained using SIPRE ice augers. Five to ten cores were collected along transects several km in length. Thickness of sea ice and snow cover were measured at each sampling site. Chlorophyll a concentrations were determined for each core. Copepods were isolated from the melted core water and identified and counted. Zooplankton tows were also made at each site where cores were collected. Nine species of copepods were identified from the cores. However, of these, only three were recorded regularly: Paralabidocera antarctica, Drescheriella glacialis and Stephos longipes. The abundance of copepods ranged between 0 and 147/L. The highest densities were recorded at the Larsemann Hills and the lowest at Murphy Rocks. Within the cores, the highest abundances were found in the bottom 10 cm of ice, irrespective of the species. Chlorophyll a concentrations ranged between 0.9 and 373 mg/m3. Data available: excel files containing sampling dates, sampling sites and abundances (number per L) of three dominant sea ice copepods, Paralabidocera antarctica, Drescheriella glacialis, Stephos longipes. Data are presented for developmental stages (nauplii, copepodites and adults) where available. Totals are also provided. Vertical distribution in some cores is also provided. Chlorophyll a concentrations (ug/L) provided for most sites. Detailed information about each of the spreadsheets is provided below: The chlorophyll spreadsheet shows chlorophyll concentrations for 5 sites in the AAT. The column headings are: core - reference number of the core collected subsection - depth in the core in cm volume - vol of melted core water volume added - 1 L of filtered seawater for melting % original - amount of total that core water represents (i.e. minus the 1L added) aliquot - volume subsampled for chlorophyll analysis acetone - amount added (mL) for extraction 750, 664, 647, 630 - wavelengths where absorbance was measured chloro a - amount of chlorophyll a in the sample ug/L - chloro a expressed as a concentration The spatial spreadsheet shows species abundances of three copepods at 4 sites N1 to NVI - nauplius stage 1 to 6 of a species CI to CVI - copepodite stage 1 to 6 of a species F or M - female or male of copepodite stage 5 or 6 1,1 etc - cores 1 and 2 from site 1 within a major location (e.g. 2 cores close together in the Larsemann Hills) The temporal spreadsheet shows abundances over time at 2 sites (O'Gorman Rocks, Bluff Is) near Davis and two species (Paralabidocera antarctica and Drescheriella glacialis) on several sampling dates N1 to N3 - total nauplii in each of three cores (i.e. not separated into stages as above) C1 to C3 - total copepodites A1 to A3 - total adults Then at the bottom are the means of each three cores.
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The aim of the study was to characterise the genetic biodiversity of populations of the copepod Paralabidocera antarctica and the cladoceran Daphniopsis studeri in the Australian Antarctic Territory. Sampling was finalised during November and December 2000. Daphniopsis studeri were sampled from freshwater lakes in the Vestfold and Larsemann Hills, and from small ponds on Heard Island. Paralabidocera antarctica were collected from saline lakes, fjords and embayments around the Vestfold Hills. Each population was analysed at 16 allozyme loci using cellulose acetate electrophoresis. Allozyme data were recorded as multilocus genotypes for each individual. The observed number of multi-locus genotypes were tested against expected values to determine whether populations of Daphniopsis studeri reproduce by obligate or cyclic parthenogenesis. Geographic genetic structure of the crustacean populations was assessed using genetic distance measures and cluster analysis. Local and regional gene flow was estimated using Fst and multivariate statistics. By using genetic tools to measure indirectly dispersal and gene flow among populations with each species, we hope to reconstruct the history of these species in Antarctica and to determine the relative significance of historical versus contemporary ecological conditions.
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Preliminary Metadata record for data expected from ASAC Project 1126 See the link below for public details on this project. ---- Public Summary from Project ---- Previous work on anti-freeze proteins (AFPs) in bacteria isolated from saline lakes in the Vestfold Hills, has shown that only around 10% of isolates possessed AFP activity. This suggests that the majority of bacteria may be using other mechanisms to avoid freezing or possibly are non-functional at sub-zero temperatures. We propose building on our previous work to ascertain if AFP occurrence is characteristic of particular taxonomic groups, or whether its evolution is random among different species. The fields in this dataset are: Lake Date Air Temperature Ice Thickness Sample Type Depth Height of ice core sample from ice/water interface Thickness of Ice core sample Salinity Water Temperature Nitrate Nitrite Ammonia Phosphate Bacteria Flagellates Chlorophyll DOC - Dissolved Organic Carbon COV of DOC - Coefficient of Variance
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Taken from sections of the report: Introduction This report describes aspects of the fieldwork completed for the Australian Antarctic Division (AAD) mapping program during the Austral summer 2003-04. The mapping program was undertaken in harmony and collaboration with the Geoscience Australia geodesy program in Antarctica, between 16th November 2003 and 2nd February 2004. Surveyors from both organisations, including Henk Brolsma (Mapping Officer, AAD) and A. Corvino (author), teamed up to successfully complete a wide range of goals. The principal objective of the Geoscience Australia geodesy program was to install three remotely located continuous GPS stations in the southern Prince Charles Mountains (PCM) and Grove Mountains (Corvino, 2004). That project is not discussed further in this report. The main objectives of the AAD mapping program were to survey ground control points (GCPs) for geo-referencing new satellite imagery and to complete terrestrial survey work in the vicinity of Davis station. The following tasks were completed: - Downloading of the tide gauges at the Larsemann Hills and Davis station; - Transfer of local sea level at the Davis tide gauge to an absolute height datum using GPS; - Establishing a new survey mark at Beaver Lake and connecting it to the existing survey marks; - Conducting GPS surveys of selected ground features for geo-referencing satellite imagery at Beaver Lake, Marine Plain, the Grove Mountains and Wilson Bluff; - Establishing new survey marks at Marine Plain in the Vestfold Hills; - Computing the alignment of the UWOSCR instrument in the Space and Atmospheric Sciences (SAS) building at Davis station; - Surveying lake levels in the Vestfold Hills; and - Various local surveying tasks at Davis station. A few aspects of the fieldwork that were completed exclusively by surveyor Brolsma are not included in this report. In particular the report is concerned with the tasks that were undertaken using GPS survey methods, which includes the tide gauge surveys, image control surveys and the fieldwork at Beaver Lake and Marine Plain. Photographs that document the fieldwork and support the text are included throughout. GPS processing reports and photographs showing the locations of the GCPs are provided as Appendices.
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Taken from sections of the report: In recent years, Geoscience Australia (GA) has increased its capability on the Antarctic continent with the installation of Continuous Global Positioning System (CGPS) sites in the Prince Charles Mountains and Grove Mountains. Over the course of the 2006/07 Antarctic summer, Alex Woods and Nick Brown from Geoscience Australia (GA) collaborated with Dan Zwartz of the Australian National University (ANU) to install new CGPS sites at the Bunger Hills and Richardson Lake and perform maintenance of the CGPS sites at the Grove Mountains, Wilson Bluff, Daltons Corner and Beaver Lake. The primary aim of the CGPS sites is to provide a reference frame for Antarctica, which is used to determine the long-term movement of the Antarctic plate. Data from Casey, Mawson and Davis is supplied to the International GPS Service (IGS) and in turn used in the derivation of the International Terrestrial Reference Frame (ITRF). The sites also open up opportunities for research into post-glacial rebound and plate tectonics. In many respects CGPS sites in Antarctica are still in their infancy. Since the mid 1990's Geoscience Australia and the Australian National University have been testing new technology and various methods to determine the most effective way of running a CGPS site in Antarctica. A more detailed review of Australia's involvement in Antarctic GPS work can be found in (Corvino, 2004) In addition, a reconnaissance survey was undertaken at Syowa Station to determine whether a local tie survey could be performed on the Syowa VLBI antenna in the future. Upgrades were made to the Davis and Mawson CGPS stations and geodetic survey tasks such as reference mark surveys, tide gauge benchmark levelling and GPS surveys were performed at both Davis and Mawson stations. In addition, work requested by Geoscience Australia's Nuclear Monitoring Project, the Australian Government Antarctic Division (AGAD) and the University of Tasmania (UTAS) were completed. The 2006/07 Geoscience Australia Antarctic expedition proved to be one of the most successful Antarctic seasons by geodetic surveyors from Geoscience Australia. All intended field locations were visited and all work tasks were completed. Background The primary aim of the CGPS sites is to provide a reference frame for Antarctica, which is used to determine the long-term movement of the Antarctic plate. Data from Casey, Mawson and Davis is supplied to the International GPS Service (IGS) and in turn used in the derivation of the International Terrestrial Reference Frame (ITRF). The sites also open up opportunities for research into post-glacial rebound and plate tectonics. In many respects CGPS sites in Antarctica are still in their infancy. Since the mid 1990's Geoscience Australia and the Australian National University have been testing new technology and various methods to determine the most effective way of running a CGPS site in Antarctica. Dr John Gibson from The University of Tasmania requested that Alex Woods and Nick Brown collect moss samples from any locations visited during the Antarctic summer field season. While working in the field only a few moss specimens were found. No moss or lichen specimens were observed at locations such as Wilson Bluff, Dalton Corner, Beaver Lake or the Grove Mountains. Moss samples were collected at Richardson Lake and Mawson Station and these samples were frozen after collection and returned to Australia. This work contributed towards AAS (ASAC) project 1159.
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1.The lakes and ponds in the Larsemann Hills and Bolingen Islands (East-Antarctica) are characterised by cyanobacteria-dominated, benthic microbial mat communities. A 56-lake dataset representing the limnological diversity among the more than 150 lakes and ponds in the region was developed to identify the nature and quantify the effects of the abiotic conditions structuring the cyanobacterial and diatom communities. 2.Limnological diversity in the lakes of the Larsemann Hills and Bolingen Islands is primarily determined by salinity and salinity related variables (concentrations of major ions, conductivity and alkalinity), and variation in lake morphometry (depth, catchment and lake area). Low pigment, phosphate and nitrogen concentrations, and DOC and TOC levels in the water column of most lakes underscore the ecological success of benthic microbial mats in this region. 3.Benthic communities consisted of prostrate, sometimes finely laminated mats, flake mats, epilithic and interstitial microbial mats. Mat physiognomy and chlorophyll/carotenoid ratios were strongly related to lake depth, but not to salinity. 4.Morphological-taxonomic analyses revealed the presence of 27 diatom morphospecies and 34 cyanobacterial morphotypes. Mats of shallow lakes (interstitial and flake mats) and those of deeper lakes (prostrate mats) were characterized by different dominant cyanobacterial morphotypes. No relationship was found between the distribution of these morphotypes and salinity. In contrast, variation in diatom species composition was strongly related to both lake depth and salinity. Shallow ponds are mainly characterised by aerial diatoms (e.g. Diadesmis cf. perpusilla and Hantzschia spp.). In deep lakes, communities are dominated by Psammothidium abundans and Stauroforma inermis. Lakes with conductivities higher than 1.5 mS/cm become susceptible to freezing out of salts and hence pronounced salinity fluctuations. In these lakes Psammothidium abundans and Stauroforma inermis are replaced by Amphora veneta. Stomatocysts were only important in shallow freshwater lakes. 5.Ice cover influences microbial mat structure and composition both directly by physical disturbance in shallow lakes and by influencing light availability in deeper lakes, as well as indirectly by generating salinity increases and promoting the development of seasonal anoxia. 6.The relationship between diatom species composition and salinity and depth is statistically significant. Transfer functions based on these data can therefore be used in paleolimnological reconstruction to infer changes in the precipitation-evaporation balance in continental Antarctic lakes. These data were also collected under the auspices of the Micromat Project, Biodiversity of Microbial mats in Antarctica (see the URL below). The fields in this dataset are: Lake Lake number Location Latitude Longitude Altitude (m) Area (ha) Catchment (ha) Depth (m) Distance from Plateau Distance from Sea Geology Substrate Presence Absence pH Alkalinity Nitrate Nitrite Ammonium Silicate Phosphate Oxygen Salinity Turbidity Conductivity Sodium Potassium Calcium Magnesium Chlorine Sulphur Bicarbonate Hydrocarbonate Total Organic Carbon Dissolved Organic Carbon