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This metadata record contains the results of two bioassays testing the response of Antarctic marine copepods to both individual and combined metals via 14 day toxicity tests. The tests were conducted during the 2012-2013 season at Davis Station, East Antarctica. Three metals (cadmium, copper and zinc) were tested singularly and in metal mixture combinations. The concentrations used in the two tests are outlined in the excel spreadsheet (AAS4100_12-13_MixedMetalTox.xlsx). Tests were carried out in 70 mL plastic vials (exposure vials) that contained 50 mL of test solutions. Test solutions were prepared by mixing stock solutions with filtered (0.45 microns) sea water and were stored in a constant temperature cabinet at 0 plus or minus 1 degree C for at least 2 hours prior to the start of tests in order to get to the required test temperature. Each treatment included four replicates and each test included eight controls. Within each replicate vial, 9-12 copepods were carefully added. No additional air, food or water was provided over the test period. At five days a water change was completed by removing the old test solution and replacing it with freshly prepared test solution at the same concentration. The tests were carried out in a constant temperature cabinet set at 0 plus or minus 1 degree C on a 16:8 light:dark photoperiod over 14 days. The number of surviving copepods were counted in each test container, at the same time each day, for 10 days and then a final count was completed on day 14. Mortality was determined by observing the copepods over 20 seconds and if there was no movement they were considered dead. Test solutions were sampled four times during the tests for measurement of metal concentrations. Samples were collected at day 0, day 5 pre-water change, day 5 post-water change and at day 10. Concentrations of the three test metals were determined in theses samples using Inductively-Coupled Plasma Optical Emission Spectrometer (ICP-OES) with appropriate matrix matched standards and blanks to ensure quality control. For all analyses, measured metal concentrations (as opposed to nominal concentrations) were used. Point estimates, including LC10 and LC50 values, were determined using the maximum likelihood-probit method using the software ToxCalc (version 5.0.26 Tidepool Scientific Software). Point estimates were calculated at 4, 7, 10 and 14 days of exposure. Whenever the assumptions for the maximum likelihood-probit method were not met then the Trimmed Spearman-Karber Analysis was used. Data are provided in an Excel workbook (filename: AAS4100_12-13_MixedMetalTox.xlsx). The first worksheet ("/Test Conditions") provides descriptive details for the tests and a key to abbreviations and units. Each worksheet includes a "This worksheet provides..." statement to assist interpretation of the data. A second data file is provided (filename: AAS4100_12-13_ToxCalc.xlsx) containing relevant test data from AAS4100_12-13_MixedMetalTox.xlsx, for input to ToxCalc software for analysis. This file also contains subsequent ToxCalc outputs, with key data (LC10 and LC50 values) provided in a summary worksheet. Other support files provided are seven images of the test species (images by Frances Alexander) and two figures showing copepod response to test solutions (% survival) over the exposure period of the two tests. Copepod samples were collected from the nearshore environment of Prydz Bay, offshore from Davis Station, on two days: 20 December 2012 and 9 January 2013. The 20 December collection was composed of Tisbe sp., collected from benthic habitats and the 9 January collection was composed of Paralabidocera Antarctica, collected from surface waters. Two 14-day laboratory-based toxicity tests were conducted in the Davis laboratories. The test dates were: 2 - 16 January 2013 (test 01; using Tisbe sp., collected 20 December 2012) and 10 - 24 January 2013 (test 02; using P. Antarctica, collected 9 January 2013).
Metadata record for data expected from ASAC Project 1152 See the link below for public details on this project. ---- Public Summary from Project ---- The small ice-free areas of Antarctica carry a remarkable range of lakes. Within the Vestfold Hills there are several hundred lakes and ponds, many of which are saline. All Antarctic freshwater and saline lakes have simple food webs that are dominated by micro-organisms (bacteria, algae and protozoa). There are no fish and very few zooplankton. These micro-organisms have evolved novel biochemicals and physiological adaptations which enable them to survive and function at sub-zero temperatures in saline lake waters. For example previous work has shown that many of the bacteria contain antifreeze proteins which prevent the cell contents from freezing. If these bacteria have invested in the evolution of antifreeze proteins they must also have developed suites of low temperatures enzymes which mediate routine cellular functions. One aspect of this project will concentrate on identifying such enzymes and quantifying their activity in different bacterial species, which will be identified using modern molecular techniques. Thus the outcome will be a picture of what enzymes occur, and which bacterial groups possess them. Low temperature enzymes have many potential industrial uses and it is hoped that some of the enzymes identified may be developed by industry. The commercial application of some low temperature enzymes, e.g. lipases, are presently being trialled Our previous work in Vestfold Hills has shown that during the Antarctic winter many of the most successful and abundant protozoans maintain active populations, so that when the brief austral summer arrives 'they hit the deck running'. In order to do this many of them possess extraordinary nutritional versatility. They are able to undertake photosynthesis like plants and eat bacteria. As day length and the light climate change in the annual cycle, such species switch from a dependence on photosynthesis in summer, to feeding on bacteria in winter. We propose investigating this phenomenon, known as mixotrophy, in a number of the dominant species (Pyramimonas and Cryptomonas) in several of the saline lakes within the Vestfold Hills. This work will contribute to understanding how pristine Antarctic lake ecosystems function; information which is fundamental to monitoring changes induced by climate change. It has recently been reported that environmental warming alters food web structure and trophic interactions (Petchy et al., 1999). These delicate ecosystems are likely to show rapid response to climatic perturbations, indeed long-term work in the Dry Valleys of Southern Victoria Land has demonstrated that Antarctic lakes are responding markedly to climate change. The download file contains an excel spreadsheet of data from Ace Lake and Highway Lake, as well as two word documents, one containing further data, and another containing details on the methods used in the data collection and analysis. The fields in this dataset are: Date Depth Chlamydomonas Cryptophyte Heterotrophic bacteria Heterotrophic nanoflagellates Ciliate Mesodinium Paralabidocera Pyramimonas Daphniopsis Chlorophyll a
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.
Colonisation of Lake Fletcher, a hypersaline, meromictic lake in the Vestfold Hills, Antarctica, by the calanoid copepod Drepanopus bispinosus, the cyclopoid copepod Oncea curvata and an undescribed cydippid ctenophore is discussed. In 1978, salinity direstly under the ice was 66 ppt and repeated net hauls found no zooplankton. In 1983, adults of D. bispinosus were found, and in 1984, a reproductively active population of this species. Surface water salinity in 1984 was 56 ppt. During winter 1986, surface salinity was 54 ppt and three zooplankton species (D. bispinosus, O curvata and an undescribed cydippid ctenophore) had established populations in the lake. In 1986/87, high tides caused nearby Taynaya Bay to flood into the lake, and three further species (the calanoid, Paralabidocera antarctica, and two harpacticoids, Harpacticus furcatus and Idomene sp.) were found in the lake. It appears that periodic flooding after 1978 caused a salinity decrease in the lake from 66 to 54 ppt, and this enabled some invertebrate species to maintain year-round populations, whereas others require marine incursions to re-establish summer only populations. The fields in this dataset are: Date Salinity Record Species
From the abstract of one of the papers: Three new zooplankton nets have been designed to enable improved collection of zooplankters from ice-covered waters. These nets also enable quantitative sampling of species not adequately sampled by other methods. The first net is a vertical tow net which can be folded like an umbrella to pass through a small ice hole (10 cm). This 'Umbrella Net' takes an integrated sample of zooplankton from all sample depths. The second net is a collapsible free-fall net designed to collect mobile zooplankters capable of avoiding towed nets. This was the only net used which was capable of collecting all furcilia stages of Euphausia crystallorophias from Ellis Fjord, Vestfold Hills, Antarctica. The third net is a diver-operated push net designed to collect zooplankters in the top 15 cm of the under-ice column. Because of the high standing crop of pytoplankton at and near the under-ice surface at particular times of the year, some species of zooplankton tend to congregate there. These species, particularly Paralabidocera antarctica, were collected in great abundance using the push net, but were rare in samples collected by other methods. The fields in this dataset are: species species density site sample
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.
Metadata record for data expected from ASAC Project 919. See the link below for public details on this project. The plankton dynamics of Ace Lake, a saline, meromictic basin in the Vestfold Hills, eastern Antarctica was studied between December 1995 and February 1997. The lake supported two distinct plankton communities; an aerobic microbial community in the upper oxygenated mixolimnion and an anaerobic microbial community in the lower anoxic monimolimnion. Phytoplankton development was limited by nitrogen availability. Soluble reactive phosphorus was never limiting. Chlorophyll a concentrations in the mixolimnion ranged between 0.3 and 4.4 micrograms per litre during the study period and a deep chlorophyll maximum persisted throughout the year below the chemo/oxycline. Bacterioplankton abundance showed considerable seasonal variation related to light and substrate availability. Autotrophic bacterial abundance ranged between 0.02 and 8.94 x 10 to the 8 per litre and heterotrophic bacterial abundance between 1.26 and 72.8 x 10 to the 8 per litre throughout the water column. the mixolimnion phtyoplankton was dominated by phytoflagellates, in particular Pyramimonas gledicola. P. geldicola remained active for most of the year by virtue of its mixotrophic behaviour. Photosynthetic dinoflagellates occurred during the austral summer, but the entire population encysted for the winter. Two communities of heterotrophic flagellates were apparent; a community living in the upper monimolimnion and a community living in the aerobic mixolimnion. Both exhibited different seasonal dynamics. The cliliate community was dominated by the autotroph Mesodinium rubrum. The abundance of M. rubrum peaked in summer. A proportion of the population encysted during winter. Only one other ciliate, Euplotes sp., occurred regularly. Two species of Metazoa occurred in the mixolimnion; a calanoid copepod (Paralabidocera antarctica) and a rotifer (Notholca sp.). However, there was no evidence of grazing pressure on the microbial community. In common with most other Antarctic lakes, Ace Lake appears to be driven by 'bottom-up' forces. The fields in this dataset are: Ace Lake Aerobic monimolimnion Ammonia Ammonium Ash free dry weight Autotrophic Bacteria Bacterial Production Leucine Bacterial Production Thymidine Biomass Carbon Cell Chlorophyll a Concentration Copepods Date Date Code Depth Diatoms Dinoflagellates Dissolved Organic Carbon Dissolved Oxygen Doubling Generation Time Heterotrophic Bacteria Heterotrophic Nanoflagellates Ice Thickness Intrinsic Growth Rate Julian Day Julian Month Mesodinium rubrum Mesodinium rubrum cysts Mixolimnion Monimolimnion Nauplii Nitrate Nitrite Notholca sp. Other Ciliates Oxygenated strata Paralabidocera antarctica copepodid Paralabidocera antarctica naupliar Particulate Organic Carbon Phosphate Phototrophic Nanoflagellates Salinity Season Soluble Reactive Phosphorus Total Ciliates Water Temperature