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.

The Davis Coastal Seabed Mapping Survey, Antarctica (GA-4301 / AAS2201 / HI468) was conducted on the Australian Antarctic Division workboat Howard Burton during February-March 2010 as a component of Australian Antarctic Science (AAS) Project 2201 - Natural Variability and Human Induced Change on Antarctic Nearshore Marine Benthic Communities. The survey was undertaken as a collaboration between Geoscience Australia, the Australian Antarctic Division and the Australian Hydrographic Service (Royal Australian Navy). The survey acquired multibeam bathymetry and backscatter datasets from the nearshore region of the Vestfold Hills around Davis Station, Antarctica. These datasets are described by the metadata record with ID Davis_multibeam_grids. This dataset comprises an interpreted geomorphic map produced for the central survey area using multibeam bathymetry and backscatter grids and their derivatives (e.g. slope, contours). Six geomorphic units; basin, valley, embayment, pediment, bedrock outcrop and scarp were identified and mapped using definitions suitable for interpretation at the local scale (nominally 1:10 000). Polygons were created using a combination of automatic extraction and manual digitisation in ArcGIS. For further information on the geomorphic mapping methods and a description of each unit, please refer to OBrien P.E., Smith J., Stark J.S., Johnstone G., Riddle M., Franklin D. (2015) Submarine geomorphology and sea floor processes along the coast of Vestfold Hills, East Antarctica, from multibeam bathymetry and video data. Antarctic Science 27:566-586. This metadata record was created using information in Geoscience Australia's metadata record at http://www.ga.gov.au/metadata-gateway/metadata/record/89984/

From the abstract of one of the papers: Oxygen microelectrodes were used to measure the photosynthetic rates of Antarctic fast ice algal mats. Using the oxygen flux across the diffusive boundary layer below the fast ice at Davis, a productivity range of 0-1.78mg C per square metre per hour was measured. This is at the lower end of fast ice productivity estimates and suggests that conventional carbon 14 techniques may overestimate sea ice algal mat productivity. Photosynthetic capacity (P max) approached 0.05 mg per C.(mg chlorophyl a) per hr. Onset of photosynthesis saturation, E k, was found at about 14 micromol photons per square metre per second. The irradiance of photoinhibition onset, E inh, was about 20 micromol photons per square metre per second and the irradiance at the compensation point, E c, was 4 micromol photons per square metre per second.

The actual piece of equipment used was an International Light IL 1700Radiometer equipped with broad band detectors to measure PAR, UV-A and erythemal UV-B. The effects of UV-B radiation on the fatty acid, total lipid and sterol composition and content of three Antarctic marine phytoplankton were examined in a preliminary culture experiment. Exponential growth phase cultures of the diatoms Odontella weissflogii and Chaetoceros simplex and the Haptophyte Phaeocystis antarctica were grown at 2 (plus or minus 1)degrees C and exposed to 16.3 (plus or minus 0.7) W.m-2 photosynthetically active radiation (PAR). UV-irradiated treatments were exposed to constant UV-A (4.39 (plus or minus 0.20) W.m-2) and low (0.37 W.m-2) or high UV-B (1.59 W.m-2). UV-B treatments induced species specific changes in lipid content and composition. The sterol, fatty acid and total lipid content and profiles for O. weissflogii changed little under low UV-B when compared with control conditions (PAR alone), but showed a decrease in the lipid content per cell under high UV-B treatment. In contrast, when P. antarctica was exposed to low UV-B irradiance, storage lipids were reduced and structural lipids increased indicating that low UV-B enhanced cell growth and metabolism. P. antarctica also contained a higher proportion of polyunsaturated fatty acids under low UV-B in comparison with PAR irradiated control cultures. The flagellate life stage of P. antarctica died under high UV-B irradiation. However, exposure of P. antarctica to high UV-B irradiance increased total lipid, triglyceride and free fat. The effect of UV-B irradiances on the lipid content of Antarctic marine phytoplankton is species specific. Changes in ambient UV-B may alter the nutritional quality of food available to higher trophic levels. EXPERIMENTAL All measurements of irradiance were made with an International Light IL 1700 Radiometer equipped with broad band detectors to measure PAR, UV-A and erythemal UV-B [14]. A National Institute of Standards and Technology intercomparison package (NIST Test #534/240436-88) was used to calibrate each light sensor. Unialgal cultures of the diatoms Odontella weissflogii and Chaetoceros simplex were isolated from sea ice collected in Prydz Bay, Antarctica during the 1990/91 austral summer. Phaeocystis antarctica was isolated from Prydz Bay in 1982/83 summer. Cultures of diatoms and Phaeocystis antarctica were maintained in 2 l glass flasks using f/2 growth medium [32] and GP5 medium [33] respectively at a temperature of 2 plus or minus 1 degrees C. Cool white fluorescent lights provided photosynthetically active radiation (PAR) intensity of 17.08 J.m-2.s-1 (84.7 micro E.m-2.s-1), with no UV-B enhancement, on a 12 h light : 12 h dark cycle. Immediately before experimental irradiation, three replicate subsamples of approximately 15 ml were obtained from each parental culture and fixed with Lugols iodine, a known sample volume sedimented, and cells counted over 15 replicate fields using a Labovert inverted microscope. Mean cell concentration and standard deviation were then computed. Each exponential growth phase parental culture was thoroughly mixed and 3 replicate 300 ml Costar polystyrene culture flasks (which completely absorbed wavelengths below 295 nm) established for each light treatment (control, low and high UV exposures). Cultures were irradiated for 24 hours in a 48 hour experimental period (6 h light : 12 h dark : 12 h light : 12 h dark : 6 h light) [14, 23]. Exposures were conducted in a Thermoline controlled environment cabinet at 2 plus or minus 1 degrees C with cool white fluorescent tubes to provide PAR and UV-A (320-400 nm), with UV-B provided by FS20T 12 UV-B Westinghouse sunlamps. PAR and UV-A irradiances were 16.3 plus or minus 0.7 W.m-2 (81.3 plus or minus 3.4 micro E.m-2.s-1) and 4.39 plus or minus 0.20 W.m-2 respectively. The spectral distribution and UV-B irradiance were varied by attenuation with glass filters [5] to provide low (0.37 W.m-2) or high UV-B (1.59 W.m-2). Sensors were each covered by an attenuating glass screen and a single layer of Costar culture flask to measure the experimental irradiances to which the algae were exposed. UV-B irradiances were chosen to reflect less than (74%) and greater than (318%) peak UV-B exposure as measured at an Antarctic coastal site (Casey station, 66 degrees S, [34]). Following irradiation each culture was well mixed and approximately 15 ml was fixed with Lugols Iodine for subsequent estimation of cell concentration (as above). Chlorotic and greatly vesicularised cells were considered to be dead [23]. The remainder of each experimental culture was filtered through Whatman GF/F filters. On completion of filtration, the filters were stored at -20C overnight before extraction of lipids the following day.

Some scanning electron microscope images were taken of dinoflagellates sampled as part of this project. A catalogue of the images taken is provided as part of the download file at the provided URL. The images are currently held by the Electron Microscope Unit of the Australian Antarctic Division, but have not yet been entered into their electron microscope database (as at the 30th of April, 2004). From the abstracts of the referenced paper: The abundance and biomass of ciliates, dinoflagellates and heterotrophic and phototrophic nanoflagellates were determined at three sites along an ice-covered Antarctic fjord between January and November 1993. The water column showed little in the way of temperature and salinity gradients during the study period. In general, the protozooplankton exhibited a seasonal variation which closely mirrored that of chlorophyll a and bacterioplankton. The fjord mouth, which was affected by the greatest marine influences, consistently had the highest densities of ciliates and the most diverse community, with up to 18 species during the sampling period. Small aloricate ciliates were present throughout the year with Strobilidium spp. being dominant during the winter. Larger loricate and aloricate ciliates became more prominent during January and November, along with the autotrophic ciliate Mesodimium rubrun and two mixotrophic species (Strombidium wulffi and a type resembling Tontonia) suggesting evidence of species successions. Data on dinoflagellates were less extensive, but these protists showed greatest species diversity in the middle reaches of the fjord. A total of 13 species of dinoflagellate were recorded. Ciliates made a significant contribution to the biomass of the microbial community in summer, particularly in the middle and at the seaward end of the fjord. In winter, heterotrophic flagellates (HNAN) and phototrophic nanoflagellates (PNAN) were the dominant component of protistan biomass. In terms of percentage contribution to the microbial carbon pool, bacteria dominated during winter and spring. To the authors' knowledge, this is the first seasonal study of an Antarctic fjord. The Ellis Fjord is very unproductive compared to lower latitude systems, and supports low biomass of phytoplankton and microbial plankton during most of the year. This relates to severe climatic and seasonal conditions, and the lack of allochthonous carbon inputs to the system. Thus, high latitude estuaries may differ significantly from lower latitude systems, which generally rank among the most productive aquatic systems in the world. The fields in this dataset are: EMU Image Number Fiona Scott Image Number Species SEM Stub Number Location Collector

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.

Introduction: During the seasons of 1954-1956 samples of liver and blood were collected from animals at Heard Island and Antarctica by members of the Australian Antarctic Expeditions. These samples were obtained primarily for determination of copper levels (see reference). Iron determinations were made concurrently by Beck and histological examinations were made on some of the liver samples by the late Dr H.W. Bennetts, at that time the Veterniary Pathologist of the Department of Agriculture. The data were not extensive enough for publication, but they are presented here for the information of other workers. Experimental: Blood was collected as it flowed from the bullet-hole after shooting. Samples were collected in bottles containing purified potassium oxalate and were subsequently preserved with purified thymol. Liver samples for analyses were preserved in a purified ethanol-formalin mixture. Those for histological studies were stored in buffered formal-saline. No special precautions were taken to remove all blood from the liver samples. Iron was estimated by the thioglycollic acid method of Mayer and Bradshaw (Analyst, 1951, 76, 715) after oxidation of organic matter with nitric, sulphuric and perchloric acids. Blood iron results are expressed as micrograms Fe per ml. If seal and penguin haemoglobin is similar to that of terrestrial species, 680 micrograms Fe per ml will equal about 20g haemoglobin per 100 ml blood. Liver results are expressed as parts per million Fe on dry matter. No correction was made for fat content as all samples (except for one leopard seal) were low in fat. The sample from the leopard seal contained 28% fat and the iron content has been calculated to a fat free basis. As it was possible that the high levels of iron are related to the diving habits of the seals, iron determinations were also made on livers from whales taken along the Australian coast. Some blood and liver iron levels for terrestrial species and for the Australian salmon are included for comparison. Results and Discussion: Detailed results for the seals and penguins and other animals are available at the url below. The levels of iron in the seal blood samples are extremely high and similar observations have been made by numerous other workers. The levels in Weddell seals Nos. 18 and 20 contain the equivalent of 30-35g haemoglobin per 100 ml blood. This level may be compared with 10-15g per 100 ml of terrestrial species. The levels of iron in the livers of the Weddell seals and in the penguins is generally higher than the corresponding values in terrestrial species. The values for elephant seals are however consistently higher than all other species. Several possible reasons can be advanced for the high iron content of the livers from elephant seals. 1) Contamination by blood is undoubtedly a factor. This is born out by the histological report of congestion of the sinusoids. Dr Budd, in a personal letter on April 17 1955, comments on the rather extraordinary slowness with which blood drains from seal liver. The fact that the very high liver iron levels are associated with heavy haemosiderin deposits indicates that blood contamination is only part of the reason for the high iron levels. 2) A small amount of contamination by black sand occurred in some of the Heard Island livers. We obtained a sample of this black sand but it contained only 3.3% soluble Fe. If there were 1% sand in the samples it would only increase the liver Fe by 330 ppm. As the sand contamination was far less than 1% I do not consider that it has contributed significantly to the liver iron values. 3) The haemosiderin may possibly be due to some virus or organism which caused blood breakdown. However, there was no comment of any sign of disease by those who collected the samples. Dr L.G.C.E. Pugh (Nature, Jan 10th 1959, 183, 74) comments on the ease of hydrolysis of Weddell seal blood and considers that the cell fragility may contribute to the high rate of destruction of red cells. If a very high destruction rate occurs in the blood of elephant seals this could account for the liver haemosiderin. 4) The high liver haemosiderin may merely be a normal iron reserve for what must be a very high iron requirement for blood production in this species. On the other hand the Weddell seals have just as high haemoglobin levels and yet the iron levels in the liver are much lower. The fields in this dataset are: antarctic blood duck fowl haemoglobin iron liver penguins petrels rabbit seals sheep skuas subantarctic whales animal No. common name scientific name taxon id locality date details blood Fe (ug/ml) liver Fe (p.p.m. on dry liver) Haemo-siderin in liver comments specials No. of samples iron content blood (micro grams per ml) iron content liver (ppm on dry matter)