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.

This is a scanned copy of the report of sediment core activities at Davis Station, 1985 by Lin Jian-ping. Paraphrased from the abstract of the report: Sediment deposited in the bottom of water provide a historical record of the biological and chemical changes which have occurred in the places since they were formed. One of the research programs at Davis in 1985 was the sediment coring program. Sediment cores were taken from some places of the Vestfold Hills, Antarctica, and were analysed for water content, total organic content and non-polar lipid content.

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.

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

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.

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).