From 1 - 8 / 8
  • Antarctic lake cores record a history of precipitation in the preservation of climate sensitive microbial communities. Comprehensive integration of our precipitation records with other climate proxies such as ice core temperature records and historical climate data are dependent upon accurate dating of this lake sediment. Fourteen lakes and ponds of the Windmill Islands were sampled in 1998 for diatoms and in 1999 for water chemistry. The waterbodies included in this study fall into one of 3 broad categories: saline lake (greater than 5m deep; greater than, or equal to, 3 parts per thousand - salinity), saline pond (less than 5m deep; greater than, or equal to, 3 parts per thousand - salinity) or freshwater pond (less than 5m deep; less than 3 parts per thousand - salinity). Saline Lakes Beall Lake, the largest lake on Beall Island, is situated in a rocky catchment with evidence of breeding penguin pairs nearby. Outflow into the small lake on the northwestern point of Beall Lake occurs at elevated lake levels. Holl Lake, the largest lake on Holl Island, is contained by ridges to the NE and SW with an obvious outflow to the SE. At the time of sampling (20 Dec 1998), penguin feathers were observed in the sediment. In 2001 large numbers of penguins were observed behind the NE ridge in addition to the numerous skuas nesting on most nearby peaks. Lake A is the westernmost lake on Browning Peninsula. This large closed saline lake has a very thick ice cover (~2.5 m) and very little evidence of birdlife. Lake M is the easternmost lake sampled on Browning Peninsula. This large closed saline lake had a very thick ice cover (3.0 m) at the time of sampling. Saline Ponds Lake Warrington is the largest waterbody on Warrington Island. Found in the centre of Warrington Island, this small shallow (1.9 m) saline pond was almost completely frozen (ice cover of 1.6 m), with ca. 0.3 m of water below the ice at the time of sampling. The lake catchment is muddy with runoff towards Robertson Channel (to the NE) and the ice cover showed signs of sediment entrapment giving a gritty texture. Lake G is located on northeastern Peterson Island. This very saline (greater than 60 ppt) shallow (1.0 m) pond was almost completely frozen (ice cover of 0.8 m), with ca. 0.1 m of water below the ice at the time of sampling. Lake G is close to breeding penguin sites and there was a noticeable discolouration of the surface water at the time of sampling. Lake I is the easternmost of the three sites visited on southern Peterson Island. This shallow (0.3 m) saline pond is very close to breeding penguin sites and was sampled by hand as the ice cover (0.1 m) was almost as thick as the lake depth. Lake K is approx. 400 m to the west of Lake I on central southern Peterson Island. This completely frozen saline pond is also very close to breeding penguin sites. Lake L is the southernmost pond sampled on Peterson Island. This almost completely frozen shallow (~0.8 m/0.8 m ice cover) saline pond is very close to breeding penguin sites with noticeable discolouration of the top ca. 0.2 - 0.3 m of water at the time of sampling. Freshwater Ponds Lake B, a shallow (0.9 m) freshwater pond, is located on the western side of Browning Peninsula, approx. 500 m to the south of Lake A. Lake C is a shallow (1.0 m) freshwater pond in the central valley of Browning Peninsula. Lake D is a shallow (0.5 m) freshwater pond in the central valley of Browning Peninsula approx. 500 m to the north of Lake C. This lake was sampled by hand as the ice cover (~0.5 m) was almost as thick as the lake depth. Lake E is a shallow (3.1 m) freshwater pond in the central valley of Browning Peninsula approx. 250 m to the north of Lake D. Lake F is the northernmost pond sampled from the central valley of Browning Peninsula. This freshwater pond is approx. 500 m to the north-west of Lake E. The sediment/species samples were collected in November and December 1998, the water samples were collected in December 1999. The fields in this dataset are: Lake Name Code Location Latitude Longitude Lake Depth Ice Depth Water Sample Salinity Lake Area Catchment Elevation Nitrite Nitrate Silicon Phosphate pH Species The numbers given in the species spreadsheet are for percentage abundance, ie the relative abundance of each species in the community.

  • ---- Public Summary from Project ---- Heard Island offers scientists a unique subantarctic laboratory for investigating climate change. We will establish a reference set of microalgal floras from lakes and lagoons and ultimately use the microalgal floras of today to investigate changes in fossil microalgal communities of Heard Island lake and lagoonal ecosystems to better understand regional subantarctic climate changes. Sediments were sampled with hand corers. Water samples were collected with a Niskin bottle. The dataset contains a summary of the locations data were sampled from, as well as average isotope concentrations from each sampling location. The fields in this dataset are: Date Location Salinity pH GPS Isotopes Concentration (ppb)

  • These data sets describe the toxicity of lead, coppyer, zinc and cadmium spiked seawater to the juveniles of Abatus ingens and Abatus nimrodi. Metals were tested separately over exposure periods of 96 and 240 hours. The experimental endpoint was mortality as defined by cessation of observable movement. The coding system for the data files is J(juvenile)_An (Abatus nimrodi) or Ai (Abatus ingens) - Metal name_Dates of the experiment_ the period of the observation (96 hour or 240 hour). This work falls under the umbrella project ASAC_2201. The fields in this dataset are: Species Toxicant Date Replicate Concentration Moving pH Salinity Dissolved Oxygen

  • This data set describes the toxicity of marine sediment spiked with contaminated soil from Thala Valley tip site at Casey. The temperate heart urchin species Echinocardium cordatum was exposed for up to 10 days with daily observations of the degree of burial of the animals. The data for this project was collected as part of the umbrella project ASAC_2201. The fields for this dataset are: Date Time Urchin Buried Alive Salinity Dissolved Oxygen pH Temperature

  • The number of people travelling to Antarctica is growing, with much of the recent increase in visitor numbers attributable to an expansion in commercial tourism (Enzenbacher 1992; 1994). Most visitors to the region seek direct interactions with the wildlife and so visit breeding groups of seals and seabirds (Stonehouse 1965; Muller-Schwarze 1984). Invariably, this involves travelling to breeding sites by helicopter, inflatable motorised boat (e.g. zodiac) or over-snow vehicle, then making relatively close approaches on foot to photograph and observe the animals. At present, there is information to suggest that visitation can have a negative effect on some Antarctic wildlife, causing changes to behaviour, physiology and breeding success (Culik et al. 1989; Woehler et al. 1994, Giese 1996; Giese 1998, Giese and Riddle 1999). However, the responses of Weddell seals (Leptonychotes weddellii) to human activity have never been systematically examined. As a result, any guidelines to control human activity around these animals are based either on opportunistic observations of seal response, and/or assumptions as to the level of disturbance seals are experiencing. Therefore, the primary objective of the research is to measure the responses of Weddell seals to various human disturbance stimuli. In so doing, the research aims to make quality information available for the development of a comprehensive and scientifically based set of guidelines for managing interactions between people and Antarctic seals. The research will adopt an experimental approach, whereby seals are experimentally exposed to particular types and intensities of human activity while their responses are objectively quantified. As far as possible, experiments are designed to replicate actual disturbances that Weddell seals are presently exposed to in Antarctica. As such, the responses of cow/pup pairs to approaches by pedestrians, over-snow vehicles and helicopters will be examined. In particular, experiments will investigate how approach distance (or altitude), approach speed, time of day, weather conditions and the time of the breeding season, influence the responses of Weddell Seals to these disturbance stimuli. Disturbance responses will be quantified by measuring the behaviour and heart rate of individual seals and the haul-out behaviour of entire groups of animals. Experiments will also be conducted to quantify the sound generated by vehicle operations in Antarctica to help determine whether anthropogenic noise effects vocal communication among Weddell seal, as indicated by changes in their calling rates. Also see the metadata record entitled: Behavioural responses of Weddell seals to human activity. At this stage most of the analysis is in progress and therefore it is not possible to provide complete data sets. These will be submitted upon the completion of the work. The attached word document summarises the experiments that have been completed during the three field seasons to date (up to the end of the 2002/2003 season), which included, the experiment type, location and sample size. The two excel data sheets 'Experimental recording details' provide information on the video recordings that were made during the 2001/2002 and the 2002/2003 summers. These details state the experimental procedure, the details of the experimental, the time, date etc. They include Hi8 video camera recordings of Weddell seal behaviour and DAT recordings of vocalisations. Biological data collected during the 2002/2003 summer include: Collected 10 sample of blood (up to 50 ml each) Collected 6 samples of urine Collected 11 samples of fur Collected 9 samples of blubber Collected 6 samples of faecal swabs (from the ice or thermometer) Conducted a post mortem on a recently deceased seal and collected organ and tissue samples. These samples are being analysed by investigators in ASAC 1144. When results are available they will documented in either ASAC 1148 or 1144. The fields in this dataset are: Date Time Tape Number Counter Number Camera Number Cow ID New ID Event Respiration Rate Heart Rate Where Approached Position of Pup Distance of Closest Pair Distance of Tide Crack Location Wind Direction Cloud Cover Temperature Wind Speed Conductivity Salinity pH Further data has been added to the archive for up to the end of the 2006. These include data files, plus scanned field notes taken during the project. Finally, video tapes relating to the project have also been stored in the Australian Antarctic Division's multimedia library.

  • This data set describes the toxicity of marine sediment spiked with undispersed diesel and diesel dispersed with Dasic Slickgone. The temperate heart urchin species Echinocardium cordatum was exposed for 10 days to each contaminant with daily observations of the degree of burial of the animals. The data for this project was collected as part of the umbrella project ASAC_2201. The fields for this dataset are: Date Time Urchin Buried Alive Salinity Dissolved Oxygen pH Temperature

  • 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

  • A variety of different chemical restraints, or anaesthetics, were trialed on Southern Elephant Seals at Heard Island and Macquarie Island. The trials were performed on female and juvenile seals, in their pre-moult stages. Further information can be found in the papers listed in the reference section below. The chemicals used in this study include: doxapram ketamine xylazine midazolam pethidine thiopentone cyclohexamine based compounds diazepam tiletamine zolazepam 4-aminopyridine Sarmazenil Yohimbine The fields in this dataset are: Anaesthetic Antagonist Dose Mass Time Heart Rate Respiratory Rate Side Effects pH PvO2 PvCO2 HCO3 Total CO2