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ANTARCTICA

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  • Metadata record for data from ASAC Project 2385 See the link below for public details on this project. ---- Public Summary from Project ---- Facilities for chemical analysis of environmental samples in Antarctica are limited, with samples frequently shipped at great expense to Australia for analysis. Development of a technique to concentrate metals from environmental samples into a thin film which can be easily transported to a laboratory for analysis is currently underway. DGT stands for Diffusive gradients in thin films, they are a passive sampling technique for trace metals based on Fick's First Law of diffusion. Basically the theory being the method: Zhang, H. and Davison, W., Anal Chem, 1995, 67, 3391-400 and Davison, W. and Zhang, H., Nature (London), 1994, 367, 546-8. Description of spreadsheets: All data were collected using DGT sediment probes or water samplers prepared from polyacrylamide diffusion layer (0.8 mm thickness, covered with a 0.13 mm thick membrane filter) and Chelex 100 binding layer (0.4 mm thick). Metadata 0304 sediment - DGT sediment probes were deployed during the 0304 summer. Samples were deployed in a 3 x 2 back-to-back array at the inner and outer sites in Brown and O'Brien Bay. ie 1.1 and 1.2 are back to back pair. All samplers were deployed for 34 days. More accurate date are on the attached s'sheet. Results shown are nanograms of metals per square centimetre accumulated in the samplers at a resolution of 2 cm. The detection limits of the metals for the samplers are based on 3 x stdev of the field blank probes. Where value = &nd& the value was less than the method detection limit. Metadata 0304 sediment Characterisation - Cores were sampled in Dec 2003 - Jan 2004 from Casey Station region. All characterisation was performed on the same 1 cm slices of core. Cores were sampled and analysed in anoxic conditions. Latitudes and Longitudess Brown Bay inner66.2803 S, 110.5414 E Brown Bay outer66.2802 S, 110.5451 E O'Brien Bay inner66.3122 S, 110.5147 E O'Brien Bay outer66.3113 S, 110.5162 E Metadata 0203 sediment - Results shown are sediment profile in nanograms of metals per square centimetre accumulated in the samplers at a resolution of 1 m. Samples 1.x were deployed for 5 days before the summer melt, 2.x were deployed for 10 days before the melt, 3.x were deployed for 15 days before the melt, 4.x were deployed for 21 days before the melt, 5.x were deployed for 28 days before the melt, 6.x were deployed for 5 days during the melt and 7.x were deployed for 20 days during the melt. The detection limits of the metals for the samplers are based on 3 x stdev of the field blank probes. Where value = 'nd' the value was less than the method detection limit. Metadata 0304 water - Results show metals in DGT water samplers deployed for 28 days. Actual times are on spreadsheet attached. Samplers were deployed in triplicate at three depths in the water column, with the depth from the sed bed meaning metres above the sea bed in the water column. Values in the original spreadsheet is nanograms of metals accumulated in sampler of 3.14cm2 area. The detection limits of the metals for the samplers are based on 3 x stdev of the field blank. Where value = 'nd' the value was less than the method detection limit. Metadata 0203 water - Results show metals in DGT water samplers deployed for 8 days. Samplers were deployed in triplicate at three depths in the water column. Depth from seabed is a measure of distance from the sea bed to the deployment depth in the water column. Values in the original spreadsheet is nanograms of metals accumulated in sampler of 3.14cm2 area. The detection limits of the metals for the samplers are based on 3 x stdev of the field blank. Where value = 'nd' the value was less than the method detection limit. ---- One thing to note, although the metal isotopes are listed, ie Cd111(LR), this is still a measure of the elemental Cd (ie all isotopes), it is just how the ICP-MS analyst presents the data when I get the raw data back. I probably should have corrected this by remove the number to remove any ambiguity involved. A pdf file of supplementary figures created from the raw data are also included as a download file. Explanations of the figures are presented below. Supplementary Data Figure Captions Figure S1. 2002 - 03 DGT water sampling results for Cd, Fe and Ni, before the melt (upper) and during the melt (lower). BB Brown Bay, OBB O'Brien Bay, top top depth, mid middle depth, bot bottom depth. Error bars represent minimum and maximum values based on three replicates and horizontal line is the detection limit based on 3s Figure S2. 2002 - 03 DGT uptake results for Mn, Fe and As in Brown Bay (upper) and O'Brien Bay (lower) for various deployment times Figure S3. 2003 - 04 DGT sediment probes results for Brown Bay outer. Upper axis represents maximum porewater concentration assuming no resupply; symbols are for 6 replicate DGT probes. Detection limit, based on 3s is represented by vertical line Figure S4. 2003 - 04 DGT sediment probes results for O'Brien Bay inner. Upper axis represents maximum porewater concentration assuming no resupply; symbols are for 6 replicate DGT probes. Detection limit, based on 3s is represented by vertical line Figure S5. 2003 - 04 DGT sediment probes results for O'Brien Bay outer. Upper axis represents maximum porewater concentration assuming no resupply; symbols are for 6 replicate DGT probes. Detection limit, based on 3s is represented by vertical line Figure S6. Sediment porewater concentrations from replicate Brown Bay outer cores Figure S7. Sediment porewater concentrations for O'Brien Bay inner (open circles) and outer (closed circles)

  • This bibliography contains references to diseases, health, clinical biochemistry and pathology of captive and wild sea birds. The definition of a sea bird is broad and includes all species that feed within the marine environment and others which are related but inhabit other aquatic environments e.g. cormorants. The bibliography is comprehensive but not exhaustive. The compilers would appreciate lists of missed and new items for inclusion. These should be sent to the data officer at the Australian Antarctic Data Centre at the contact details listed below.

  • This model was produced as part of Australian Antarctic Science project 4037 - Experimental krill biology: Response of krill to environmental change - The experimental krill research project is designed to focus on obtaining life history information of use in managing the krill fishery - the largest Antarctic fishery. In particular, the project will concentrate on studies into impacts of climate change on key aspects of krill biology and ecology. This metadata record is to reference the paper that describes the model. There is no archived data output from this data product. Taken from the abstract of the referenced paper: Estimates of productivity of Antarctic krill, Euphausia superba, are dependent on accurate models of growth and reproduction. Incorrect growth models, specifically those giving unrealistically high production, could lead to over-exploitation of the krill population if those models are used in setting catch limits. Here we review available approaches to modelling productivity and note that existing models do not account for the interactions between growth and reproduction and variable environmental conditions. We develop a new energetics moult-cycle (EMC) model which combines energetics and the constraints on growth of the moult-cycle. This model flexibly accounts for regional, inter- and intra-annual variation in temperature, food supply, and day length. The EMC model provides results consistent with the general expectations for krill growth in length and mass, including having thin krill, as well as providing insights into the effects that increasing temperature may have on growth and reproduction. We recommend that this new model be incorporated into assessments of catch limits for Antarctic krill.

  • Adelie penguin breeding success records for Bechervaise Island, Mawson since 1990-91. Data include counts of occupied nests and chick counts when either 2/3 of the nests have creched or when all nests have creched. Breeding success values are calculated as the number of chicks per occupied nest. Breeding Success = the number of chicks raised to fledging per nest with eggs Breeding success is calculated from four different whole island counts: 1) the number of incubating nests (i.e. the number of nest with eggs) - 'incubating nest count' 2) the number of brooding nests (i.e. the number of nests brooding chicks) - 'brooding chick count' 3) the number of chicks present when 2/3 of the nests have creched their chicks - '2/3-creche count' 4) the number of chicks present when all the nests have creche their chicks - 'fully-creche count' Each colony on the island is manually counted by field observers, using 'counters', three times each. Counts within 10% of each other are used to average the number of nests or chicks for each colony and then in later calculations to determine breeding success. Incubating nest counts are conducted on or about 2nd December; Brooding chick counts are conducted on or about the 7th January; 2/3-creche counts on or about the 19th January; and Fully-creche chick counts on or about 26th January. Whole island 2/3-creche and fully-creche chick count dates are determined from calculating when 2/3 and all study nests in the census area (study colonies) have creche their chicks. This work was completed as part of ASAC Project 2205, Adelie penguin research and monitoring in support of the CCAMLR Ecosystem Monitoring Project. The fields in this dataset are: Year Breeding success Occupied nests

  • This dataset represents extents of Antarctic sea ice derived from passive microwave data. It includes: maximum and minimum sea ice extent based on 1989 - 99 data; maximum sea ice extent by month for the period October - March based on 1973 - 98 data; mean sea ice extent by month based on 1973 - 1998 data; and maximum sea ice extent averaged over the period 1987 - 1998. The data referenced by this metadata record has been sourced from another metadata record in this catalogue. For more information on the dataset see: Antarctic CRC and Australian Antarctic Division Climate Data Set - Northern extent of Antarctic sea ice [climate_sea_ice].

  • This study employs data from two satellite-borne instruments namely, the Sea-Viewing Wide Field-of-view Sensor (SeaWiFS) and the Total Ozone Mapping Spectrometer (TOMS). This work was completed as part of an honours project under ASAC project 2210 (UV climate over the Southern Ocean south of Australia, and its biological impact). Further information about the project is available in the word document available for download (extract from the honours thesis). The fields in this dataset are: Region Year Day (Julian Day) Pixels (number of cloud free pixels from SeaWiFS sensor that were available for analysis) Mean Chlorophyll (milligrams per cubic metre) (derived from cloud free pixels) Standard Deviation Ozone (dobson units) from the TOMS sensor (average for whole region).

  • Current meter S4_211b is one of four current meters deployed off the coast of Casey Station, Australian Antarctic Territory. S4_211a was located in Shannon Bay at 66 degrees 16.727 minutes South, 110 degrees 31.434 minutes West. Further deployment details can be found in the 'Mooring Details' section of the data, as well as a 'Location Map'. The data includes: current speed components, current speed and current direction, a progressive vector diagram of displacement, and water temperature. The data were recorded by the Australian Antarctic Division, and processed by Oceanographic Field Services Pty Ltd. Data was recorded between 3:30am 18 November 1997 (GMT) and 7:30am 29 December 1998 (GMT). The fields in this dataset include: Date Time Speed (centimetres per second) Direction (degrees) Temperature (degrees)

  • This dataset contains records of ice thickness and snow thickness from Davis Antarctica. Measurements were attempted on a weekly basis and have been recorded since 1957 and are ongoing, although data have only been archived here until 2002. The observations are not continuous however. The dataset is available via the provided URL. This data were also collected as part of ASAC projects 189 and 741. Logbook(s): Glaciology Davis Sea Ice Logs 1992-1999

  • From the referenced paper: The frigid concentration or freezing of seawater is an important natural phenomenon in the polar regions and results in the precipitation of a different sequence of salts - and thus produces brines of different composition - to that formed during isothermal evaporation under temperate conditions (about 20-25 degrees C). Seawater freezing, however, has been studied less extensively than evaporation and somewhat greater uncertainty exists over the exact nature of the compositional pathway followed. Most investigators have shown that the precipitation of mirabilite (Na2SO4 - 10 H2O) or gypsum (CaSO4 - 2 H2O), which both occur at the same seawater concentration factor (SWCF), is the critical difference between frigid and evaporative concentration, respectively, a consequence of the very different temperature dependence of the solubilities of these salts, as well as the effect of sodium chloride on these properties. This difference can be considered to represent a temperature-dependent chemical divide in the closed-basin concentration of seawater because it determines significantly the major ion composition of the brine and the salt mineral assemblage precipitated on further evolution of the system. Recently new insights into seawater freezing have been achieved through improvements in existing chemical equilibrium models. Along with the results of some associated experimental work, this has provided evidence for the formation of gypsum during freezing, contradicting the accepted Ringer-Nelson-Thompson model of frigid concentration firmly established in the 1950's and through subsequent studies, but validating an alternative model proposed by Gitterman two decades later.

  • Current meter S4_212b is one of four current meters deployed off the coast of Casey Station, Australian Antarctic Territory. S4_211a was located in Shannon Bay at 66 degrees 16.727 minutes South, 110 degrees 31.434 minutes West. Further deployment details can be found in the 'Mooring Details' section of the data, as well as a 'Location Map'. The data includes: current speed components, current speed and current direction, a progressive vector diagram of displacement, and water temperature. The data were recorded by the Australian Antarctic Division, and processed by Oceanographic Field Services Pty Ltd. Data was recorded between 3:30am 18 November 1997 (GMT) and 7:30am 29 December 1998 (GMT). The fields in this dataset include: Date Time Speed (centimetres per second) Direction (degrees) Temperature (degrees)