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EARTH SCIENCE > BIOSPHERE > ECOSYSTEMS > FRESHWATER ECOSYSTEMS > LAKE/POND

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  • This is a scanned copy of the vertebrate ecologists report from Davis Station in 1983, written by Rhys Puddicombe. Taken from the report: This annual report covers the period 9/11/82 to 10/12/83. As such it is an incomplete record, as some projects are ongoing until mid-January 1984, whilst others will be begun and completed between early December and mid-January. Where this is the case only a brief outline will be presented to illustrate the aims of these projects. This report will generally deal only with practical work and raw results as the majority of analyses will not be completed until early 1984. The two major projects for the year have been seal tagging/resighting, and penguin vomit analysis. Several additional projects are complementary to this work, but for clarity's sake will be covered separately. Finally, several minor projects have involved either observations or data and material collections for analysis by people in Australia. Topics covered by this report: Lakes Fishing Fat collection Briefing/equipping members of Dick Smith Explorer Elephant Seals - Davis Beach census - Day trips - Branding - Collection of teeth and toenails - Seal census on voyage through pack ice Weddell Seals - Faeces collection for Ken Green - Seal recording - Seal tagging/resighting - Aerial weddell surveys/census Seabird census from Australia to Mawson Ice Edge Giant Petrel banding Vomiting of Southern Fulmars and Cape Petrels and bolus collection of Skuas and Giant Petrels Emperor Penguin vomiting Adelie penguins - Blood collections - Dead adelie collection - Egg collection - Penguin banding - Counts of breeding reference groups - Adelie vomiting

  • From the abstract of one of the papers: Phytoplankton biomass and speciation were monitored at an inshore site near Davis Station, East Antarctica during three consecutive summer seasons (December-February, 1992-5). Four distinct phytoplankton assemblages were identified in which the dominant species were: Phaeocystis sp., an undescribed Cryptomonas species, Thalassiosira dichotomica, and a mixed assemblage containing Fragilariopsis spp. and Nitzschia spp. Little interannual consistency was found in either the timing of the appearance or disappearance of the various assemblages. Similarly, the seasonal trends in biomass varied dramatically from year to year. Variations in the phytoplankton community can be ascribed, to some extent, to the random variation in a number of factors, including the date of fast ice break out, water column stratification, temperature and salinity, zooplankton grazing and strong winds. Periods of strong wind result in the introduction of offshore or deeper water masses into the shallow inshore environment, where the physical and chemical conditions allow blooms to develop. A number of the papers listed in the reference section are available as pdf's in the download section.

  • ---- 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.

  • High resolution digital aerial photography of Adelie penguin colonies, Davis Station, Heidemann Valley, and other various areas, LIDAR scanning of portions of the Vestfold Hills, Rauer Islands and sea ice in front of the Amery Ice Shelf, conducted from 2009/11/17 to 2009/11/23. Some of the aerial photography has been conducted in support of various AAS projects: AAS 3012 (ASAC_3012) AAS 2722 (ASAC_2722) AAS 1034 (ASAC_1034) AAS 3130 (ASAC_3130) A short list of the work carried out: - Long duration over water/sea ice flights for the purposes of "Investigation of physical and biological processes in the Antarctic sea ice zone during spring using in situ, aircraft and underwater observations". - Over-flights at 750m over specific islands in the Vestfold Hills and Rauer Islands known to hold Adelie colonies. - Transects of flights were performed over Davis station, at 500m altitude, taking photos and LIDAR measurements. - The evaluation of the APPLS equipment (camera, LIDAR, electronics, software) was performed and in parallel to the other tasks. - Production a digital elevation model of the Heidemann Bay Area. - Aerial photography / LIDAR of moss beds in the Vestfold Hills area. - The Marine Plain area, south east of Davis, was mapped using LIDAR and aerial imagery for the purposes of general Antarctic information. - The Vestfold Lakes, particularly Lake Druzby, Watts Lake, Lake Nicholson and Crooked Lake provide interesting aerial imagery. - The opportunity was taken to visit the plateau skiway (at 'Woop woop') and estimate the effort in opening the skiway later in the season. - Fly over and photograph the length of the resupply fuel hose from the AA to the shore. - The Russian 'Progress 1 and 2', and Chinese Zhong Shan stations were over flown and aerial imagery collected. Taken from the report: This document describes the results of the use of the APPLS (Aerial Photographic Pyrometer Laser System) at Davis during resupply 2009/2010 (November 17 to 24, 2009). This document is primarily for Science Technical Support use. Portions of the report can be used to provide information on the results obtained to other parts of AAD.

  • Taken from the report: This document describes the results of the use of the APPLS (Aerial Photography Pyrometer LiDAR System) during underway science (sea ice) on the way to Davis, and later at Davis during resupply 2010/2011 (November 16 to 20, 2010). This document is primarily for Science Technical Support use. Portions of the report can be used to provide information on the results obtained to other parts of AAD. Some of this aerial photography has also been conducted in support of various AAS projects: AAS 3012 (ASAC_3012) AAS 3113 (ASAC_3113) AAS 2205 (ASAC_2205) AAS 2425 (ASAC_2425) AAS 3154 (ASAC_3154) AAS 3189 (ASAC_3189) A short list of the work carried out: - 3012, 3113 This activity involved long duration over water/sea ice flights for the purposes of "Investigation of physical and biological processes in the Antarctic sea ice zone during spring using in-situ, aircraft and underwater observations". This activity was scheduled for prior to Davis, over pack ice far from shore. Two science specific flights were made, and one opportunistic (sea ice reconnaissance), for a total of 5 hours 19 minutes of data collection for dedicated science - 2205 Priority 1 - Adelie Penguin Census Survey on the Islands in the Davis vicinity This task was a repeat of aerial census of Adelie penguins, conducted in 2009/2010 with coordinated ground counts of specific islands/colonies on Gardner, Magnetic, Lugg and Turner Islands. The ground counts were performed at the same time as the aerial survey, to compare aerial versus ground counts. Personnel from the CEMP Penguin Monitoring Program (Colin Southwell, Barbara Wienecke) performed ground counts coordinated with the flying on two days. The Flight lines were initially done on 2010/11/18 in bright sunlight, and then repeated on 2010/11/20 during overcast weather to compare the different image quality due to lack of shadows cast by the penguins. Priority 2 - Aerial photographic survey of the Svenner Group Islands Flights over Adelie Penguin colonies were performed at 750m, using 150mm lens, and then only over the islands known to host Adelie colonies. Flying time total = 5 hours, 51 minutes - 2425 This task was to survey the Woop Woop Skiway, over an area of 320 square kilometres. Due to time constraints, only every 2nd line was flown after consultation with AAD Air-operations (Steve Daw and Matt Filipowski). Flying time total = 4 hours 25 minutes - 3154 This task was to capture an aerial photograph of a Hawker Island Giant Petrel colony, being monitored by nest cameras. A run was conducted on 2010/11/19 in bright sunlight and also repeated on 2010/11/20 in flat light. Flying time total = 22 minutes - 3189 This task was to survey potential sites, in the Vestfold Hills near Davis, for a Nuclear Test Ban Treaty monitoring installation. Flying time total = 29 minutes

  • The data set includes information relevant for the study and description of sea-ice bacteria contains the following dataset subgroups and is organised by REFERENCE number. 1) Isolation data: strain designations (e.g. culture collection names are indicated for type cultures); media used for isolation and routine cultivation; temperature used for incubation; any special conditions (e.g. enrichment conditions) used for isolation; isolation site and type (e.g. sea-ice); availability of the indicated strain from the chief investigator (J. Bowman) 2) Phenotypic data: Includes morphological, physiological and biochemical tests performed. Details on how these were performed are indicated in the relevant reference. 3) Growth/temperature data: data for temperature related growth curves are given where available. Methods are indicated in the associated reference. 4) Fatty acid/chemotaxonomy data: fatty acid and other related data are given where available. Methods are indicated in the associated reference. 5) Genotypic data: data for DNA-guanosine/cytosine-content and genomic DNA:DNA hybridization are shown where available. Methods are indicated in the associated reference. 6) Phylogenetic data: data for sequences are cross-referenced to the GenBank database. In some cases, aligned sequence datasets are available in FASTA format and can be viewed in the programs BIOEDIT (www.mbio.ncsu.edu/BioEdit/bioedit.html) or CLUSTAL W (www.ebi.ac.uk/clustalw). 7) Other related published references which are useful or relevant to the dataset e.g. related sequences published subsequent to the ASAC study

  • From the abstracts of some of the referenced papers: The relationship between surface sediment diatom assemblages and measured limnological variables in 33 coastal Antarctic lakes was examined by constructing a diatom-water chemistry dataset. Canonical correspondence analysis revealed that salinity and silicate each explain significant amounts of variation in the distribution and abundance of the surface sediment diatom taxa. Salinity has the strongest influence, revealing its value for limnological inference models in this coastal Antarctic region. A comprehensive diatom stratigraphy is used to calculate a palaeosalinity history for an Antarctic lake via an established diatom-salinity transfer function for the Vestfold Hills, Antarctica. A sediment core taken from Ace Lake in 1995 shows three distinct changes in diatom assemblage constituents: initial benthic hyposaline - freshwater taxa are replaced by marine planktonic and sea-ice taxa with these taxa in turn replaced by the benthic hypersaline taxa dominant in the lake today. These changes in assemblage composition enable the lakewater salininty of each stage to be determined, and the Holocene evolution of the lake to be refined. Deglaciation of the Vestfold Hills at the beginning of the Holocene exposed Ace Lake basin; following this, fresh lacustrine diatoms were deposited from ~11 380 to ~8110 corrected 14C yrBP. Relative sea-level rise after this time led to the progressive marine inundation of the lake and the deposition of marine diatom taxa. Marine taxa were dominant in the sediment for more than 6000 years. Isostatic rebound and stabilisation of the sea-level isolated Ace Lake and at ~1480 corrected 14C yrBP saline lacustrine diatoms became the dominant taxa, indicative of the concentration of dissolved salts through evaporation after isolation.

  • This record relates to the Australian component of the Latitudinal Gradient Project. The LGP is largely a New Zealand, US and Italian venture, but a small contribution has been made by Australian scientists. The Australian component of this work was completed as part of ASAC projects 2361 and 2682 (ASAC_2361, and ASAC_2682). Data from this project were entered into the herbarium access database, which has been linked to this record. The list below contains details of where and when samples were collected, and also the type of sample and the method of sampling. Cape Hallett and vicinity (2000, 2004): Biodiversity assessment of terrestrial plants (mosses, lichens); Invertebrate collections (mites, Collembola); plant ecology and community analysis; photosynthetic physiology of mosses and lichens; molecular genetics of mosses and lichens. Random sampling for biodiversity studies; point quadrats, releves for vegetation analysis, field laboratory experiments for physiological studies. Dry Valleys: Taylor Valley (1989, 1996), Garwood Valley (2001), Granite Harbour (1989; 1994, 1996) - plant ecology; plant physiology; biodiversity; invertebrate collections; molecular genetics of mosses. Random sampling for biodiversity studies; point quadrats, releves for vegetation analysis, field laboratory experiments for physiological studies. Beaufort Island (1996) - plant biodiversity; molecular genetics of mosses. Random sampling for biodiversity studies; point quadrats, releves for vegetation analysis, laboratory studies for molecular genetics. Darwin Glacier (1994): plant biodiversity; molecular genetics of invertebrates and mosses (random sampling for biodiversity; laboratory studies of invertebrate and moss molecular genetics). Project objectives: 1. Investigate the distribution of bryophytes and lichens in continental Antarctica 1a). to test the null hypothesis that species diversity does not change significantly with latitude; 1b). to explore the relationships between species and key environmental attributes including latitude, distance from the coast, temperature, substrate, snow cover, age of ice-free substrate. 2. To continue to participate in the Ross Sea Sector Latitudinal Gradient Project and develop an Australian corollary in the Prince Charles Mountains, involving international collaborators, incorporating the first two objectives of this project. 3. To develop an international collaborative biodiversity and ecophysiological program in the Prince Charles Mountains that will provide a parallel N-S latitude gradient study to mirror the LGP program in the Ross Sea region as part of the present RISCC cooperative program (to be superseded by the EBA (Evolution and Biodiversity of Antarctica) program) to address the above objectives. Taken from the 2008-2009 Progress Report: Progress against objectives: Continuing identification of moss and lichen samples previously collected from Cape Hallett, Granite Harbour and Darwin Glacier region. Lecidea s.l. lichens currently being studied in Austria by PhD student. Field work in Dry Valleys significantly curtailed by adverse weather. Field work planned for Darwin Glacier region and McMurdo Dry Valleys, particularly Taylor Valley and Granite Harbour region was severely curtailed due to adverse weather, helicopter diversions due to a Medical Evacuation, and other logistic constraints. 10 days of field time were lost. Limitations on field travel in Darwin Glacier region restricted the field work to a biologically depauperate region. The Prince Charles Mountains N-S transect, the only continental transect possibility for comparison with the Ross Sea area, unfortunately appears to have been abandoned through lack of logistic support. Taken from the 2009-2010 Progress Report: Identification of samples collected from AAT and Ross Sea Region continued during the year, interrupted significantly by the packing of the collection and transfer of specimens to the Tasmanian Herbarium. Work is now proceeding at the Herbarium with sorting, databasing and incorporation of packets into the Herbarium collection. The merging of the collection provides long-term security of curation and significantly boosts the cryptogam collections (35000 numbers) of the Tasmanian Herbarium.

  • Antarctic sediments and sea-ice are important regulators in global biogeochemical and atmospheric cycles. These ecosystems contain a diverse range of bacteria whose biogeochemical roles remains largely unknown and which inhabit what are continually low temperature habitats. An integrated molecular and chemical approach will be used to investigate the coupling of microbial biogeochemical processes with community structure and cold adaptation within coastal Antarctic marine sediments and within sea-ice. Overall the project expects to make an important contribution to our understanding of biological processes within low temperature habitats. DATA SET ORGANISATION: The dataset is organised on the basis of publication and is organised on the basis of the following sections: 1. SEDIMENT SAMPLES and ISOLATES Samples collected are described in terms of location, type and where data were obtained chemical features. The designation, source, media used for cultivation and isolation and availability of sediment and other related isolates are provided. Samples included are from the following locations: Clear Lake, Pendant Lake, Scale Lake, Ace Lake, Burton Lake, Ekho Lake, Organic Lake, Deep lake and Taynaya Bay (Burke Basin), Vestfold Hills region; and the Mertz Glacier Polynya region. 2. BIOMASS and ENZYME ACTIVITY DATA Biomass, numbers and extracellular enzyme activity data are provided for Bacteria and Archaea populations from Mertz Glacier Polynya shelf sediments. 3. FATTY ACID and TETRAETHER LIPID DATA Phospholipid and tetraether lipid data are provided for Mertz Glacier Polynya shelf sediments. Whole cell fatty acid data are provided for various bacterial isolates described officially as new genera or species. 4. RNA HYBRIDISATION DATA RNA hybridisation data for Mertz Glacier Polynya sediment samples is provided, including data for oligonucleotide probes specifc for total Bacteria, Archaea, the Desulfosarcina group (class Deltaproteobacteria, sulfate reducing bacterial clade), phylum Planctomycetes, phylum Bacteroidetes (Cytophaga-Flavobacterium-Bacteroides), class Gammaproteobacteria, sulfur-oxidizing and related bacteria (a subset of class Gammaproteobacteria) and Eukaryota. 5. PHYLOGENETIC DATA 16S rRNA gene sequence data are indicated including aligned datasets for three clone libraries derived from the Mertz Glacier Polynya including GenBank accession numbers. Sequence accession numbers are provided for Vestfold Hills lake sediment samples. In addition GenBank numbers are provided for denaturing gradient gel electrophoresis band sequence data from Mertz Glacier Polynya shelf sediment. Other forms of this DGGE data (banding profile analysis) are available in reference Bowman et al. 2003 (AAD ref 10971).