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EARTH SCIENCE > BIOSPHERE > ECOLOGICAL DYNAMICS > ECOSYSTEM FUNCTIONS > NUTRIENT CYCLING

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  • Metadata record for data from ASAC Project 133 See the link below for public details on this project. Surface carbon dioxide (CO2) observations are integral to understanding the role of the Southern Ocean in the global carbon cycle, and to developing reliable predictions of biogeochemical responses to altered climatic conditions. Carbon dioxide (CO2) observations made in surface waters of the Australian sector of the Southern Ocean between the years 1991 and 2002 were used to estimate the seasonal variability in the fugacity of CO2 (fCO2) and net air-sea carbon fluxes. The results showed a net annual uptake of CO2 by the surface ocean over the entire region. The greatest seasonal uptake and lowest fCO2 values were observed in Spring/Summer in the sub-Antarctic zone (SAZ: 44 degrees S-50 degrees S) and in the Seasonal Sea-ice Zone (SIZ: south of 62 degrees S). The seasonal maximum in uptake for these regions is consistent with increased phytoplankton biomass and shoaling mixed layers over the Spring/Summer period. The High Nutrient Low Chlorophyll waters between 50 degrees S and 62 degrees S, also had maximum uptake in summer, but less compared to the SAZ and SIZ regions. Winter surface waters were close to or slightly above equilibrium, with respect to atmospheric CO2. The reduced uptake in winter appeared due to deeper mixing, lower biomass, and air-sea CO2 exchange. The highest fCO2 values in Winter were observed under or near the seasonal sea-ice where entrainment of deeper CO2-rich waters and ice cover would maintain high surface fCO2 values. The smallest seasonal amplitude in the surface fCO2 and net air-sea fluxes was found from 51 degrees S to 54 degrees S, a region on the southern edge of the SAZ and between the North sub-Antarctic Front and North Polar Front. The uptake estimates derived from the data were in good agreement with the CO2 flux climatology of Takahashi (2002), except in the SAZ and SIZ where we observed greater and less uptake, respectively. Data for this project are available for download - the dataset consists of a data files, and some excel files, which provide further information about each data file (cruise, dates, etc). Furthermore, the column headings used in the data files are as follows: Cruise - name of the cruise which collected the data Date - UTC Time - in UTC Latitude - decimal Longitude - decimal Sst - Sea Surface Temperature in degrees C Teq - Temperature of surface water at which the CO2 measurement is made. Sal - Salinity Patm - atmospheric pressure in hectopascals Shipspd - ship speed in knots Windspd - wind speed in knots Winddir - wind direction in degrees xCO2 - Mole fraction of CO2 in air (dry) equilibrated with surface water and at equilibrator water temperature xCO2air - Mole fraction of CO2 in atmosphere, dry pCO2 - partial pressure of carbon dioxide in surface water

  • This metadata record is a 'Parent' metadata record for ASAC project 2720. See the link for the related 'Child' metadata records. The overall objective is to characterise Southern Ocean marine ecosystems, their influence on carbon dioxide exchange with the atmosphere and the deep ocean, and their sensitivity to past and future global change including climate warming, ocean stratification, and ocean acidification from anthropogenic CO2 emissions. In particular we plan to take advantage of naturally-occurring, persistent, zonal variations in Southern Ocean primary production and biomass in the Australian Sector to investigate the effects of iron addition from natural sources, and CO2 addition from anthropogenic sources, on Southern Ocean plankton communities of differing initial structure and composition. SAZ-SENSE is a study of the sensitivity of Sub-Antarctic Zone waters to global change. A 32-day oceanographic voyage onboard Australia's ice-breaker Aurora Australis was undertaken in mid-summer (Jan 17 - Feb. 20) 2007 to examine microbial ecosystem structure and biogeochemical processes in SAZ waters west and east of Tasmania, and also in the Polar Frontal Zone south of the SAZ. The voyage brought together research teams from Australasia, Europe, and North America, and was led by the ACE CRC, CSIRO Marine and Atmospheric Research, and the Australian Antarctic Division. The overall goal is to understand the controls on Sub-Antarctic Zone productivity and carbon cycling, and to assess their sensitivity to climate change. The strategy is to compare low productivity waters west of Tasmania (areas with little phytoplankton) with higher productivity waters to the east, with a focus on the role of iron as a limiting micro-nutrient. The study also seeks to examine the effect of rising CO2 levels on phytoplankton - both via regional intercomparisons and incubation experiments. Available for download from this metadata record are various datasets collected from the voyage: - An image showing a map of the cruise track. - An excel document detailing hourly position checks of the ship. - An excel document detailing the event log for the voyage. - A word document detailing prospective papers produced from the voyage. Finally a link is available for users to access the special volume of publications produced as a result of this voyage.

  • 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.

  • A variety of epifaunal invertebrates were collected from hard substrates and soft sediment habitats at various sites in the Windmill Islands near Casey station in East Antarctica. Collected fauna were frozen (-18oC) and returned to Australia for analysis. Stable isotope analysis (carbon and nitrogen) was conducted on 376 samples. This work was completed as part of ASAC project 2948 (ASAC_2948), "TRENZ: The TRophic Ecology of the antarctic Nearshore Zone: local and global constraints on patterns and processes".

  • Exopolysaccharide (EPS) is complex sugar made by many microbes in the Antarctic marine environment. This project seeks to understand the ecological role of microbial EPS in the Southern Ocean, where it is known to strongly influence primary production. We will investigate the chemical composition and structure of EPS obtained from Antarctic microbes, which will improve our knowledge of its ecological significance and biotechnological potential. Dataset includes the following: 1) Information on Exopolysaccharide-producing bacterial isolates, isolation sites, media used and growth conditions. 2) 16S rRNA gene sequence and fatty acid data of isolates for strain identification. 3) Exopolysaccharide chemistry data including EPS carbohydrate composition, organic acid composition, sulfate content, molecular weight. 4) Physiology of exopolysaccharide synthesis. Effects of temperature and other factors on EPS yield and glucose conversion efficiency. 5) Iron binding properties. The download file includes: 11 files File 1. Bacterial isolate 16S rRNA gene sequences obtained from Southern Ocean seawater or ice samples. The sequences are all deposited on the GenBank nucleotide (NCBI) database. Sequences are in FASTA format. File 2. Seawater and sea-ice sample information including sites samples, sample type. File 3. Data for exopolysaccharide (EPS)-producing bacteria isolated and subsequently selected for further studied. Information indicates special treatments used to obtain strains including plankton towing, filtration method, and enrichment. Identification to species level was determined by 16S rRNA gene sequence analysis. File 4. EPS-producing bacterial isolate fatty acid content determined using GC/MS procedures. File 5. Basic chemical data for EPS from Antarctic isolates including protein, sulfate, and sugar type relative content (determined by chemical procedures), molecular weight in kilodaltons and polydispersity (determined by gel-based molecular seiving). File 6 Monosaccharide unit composition determined by GC/MS of EPS from Antarctic isolates. File 7. Effect of temperature on culture viscosity and growth of EPS-producing bacterium Pseudoalteromonas sp. CAM025 as affected by temperature. File 8. Effect of temperature on EPS and cell yields and EPS synthesis efficiency (as indicated by glucose consumption) of EPS-producing bacterium Pseudoalteromonas sp. CAM025 as affected by temperature. File 9. Efficiency of copper and cadmium metal ion adsorption onto EPS from EPS-producing bacterium Pseudoalteromonas sp. CAM025. File 10. Phenotypic characteristics data for novel EPS-producing Antarctic strain CAM030. Represents type strain of Olleya marilimosa. File 11. Effect of temperature on chemical make up of EPS from EPS-producing bacterium Pseudoalteromonas sp. CAM025.

  • Metadata record for data from ASAC Project 2720 See the link below for public details on this project. The overall objective is to characterize Southern Ocean marine ecosystems, their influence on carbon dioxide exchange with the atmosphere and the deep ocean, and their sensitivity to past and future global change including climate warming, ocean stratification, and ocean acidification from anthropogenic CO2 emissions. In particular we plan to take advantage of naturally-occurring, persistent, zonal variations in Southern Ocean primary production and biomass in the Australian Sector to investigate the effects of iron addition from natural sources, and CO2 addition from anthropogenic sources, on Southern Ocean plankton communities of differing initial structure and composition. These samples were collected on the SAZ-SENSE scientific voyage of the Australian Antarctic Program (Voyage 3 of the Aurora Australis, 2006-2007 season). SAZ-SENSE is a study of the sensitivity of Sub-Antarctic Zone waters to global change. A 32-day oceanographic voyage onboard Australia's ice-breaker Aurora Australis was undertaken in mid-summer (Jan 17 - Feb. 20) 2007 to examine microbial ecosystem structure and biogeochemical processes in SAZ waters west and east of Tasmania, and also in the Polar Frontal Zone south of the SAZ. The voyage brought together research teams from Australasia, Europe, and North America, and was led by the ACE CRC, CSIRO Marine and Atmospheric Research, and the Australian Antarctic Division. The overall goal is to understand the controls on Sub-Antarctic Zone productivity and carbon cycling, and to assess their sensitivity to climate change. The strategy is to compare low productivity waters west of Tasmania (areas with little phytoplankton) with higher productivity waters to the east, with a focus on the role of iron as a limiting micro-nutrient. The study also seeks to examine the effect of rising CO2 levels on phytoplankton - both via regional intercomparisons and incubation experiments. The data described in this metadata record are for seawater samples collected for HPLC pigments, microscopy and flow cytometry. Samples were collected either by Niskin Bottles (on a CTD), from the ocean surface with a bucket, or via a clean seawater line (at a depth of 7 metres), directly into the onboard laboratories. Samples for microscopy were examined either with an electron microscope, or a light microscope (lugol samples). The data are presented in an excel spreadsheet, available for download at the URL given below. The 'Notes' worksheet provides further information about the data contained in the spreadsheet, including a description of column headings, units used, etc. The fields used in this dataset are: Tube Label Site CTD Niskin bottle Depth (m) Date (UT) Start Time (UT) Stop Time (UT) Latitude Longitude Lugols Glutaraldehyde fixed samples Flow Coccolithophorids Volume HPLC Volume Turner Fluorometer reading (PAR) Photosynthetically Active Radiation Temperature (degrees C) Comment

  • 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).