This dataset contains data resulting from the measurement of brine samples extracted from the sea-ice during the 2012 SIPEX 2 (Sea Ice Physics and Ecosystems Experiment) marine science voyage. The Brine was collected from partially drilled holes in the ice using suction. In some of these cases the brine analysed came from holes which correspond to permeability measurements. In these cases a core number is associated with the brine data which will correspond to the core number in the permeability data set found in the master core list Excel file. The purpose of this data set was to act as a first step to quantify the effect that extra cellular carbon may have on the physical properties of brine and sea ice. At least 1 litre of brine was collected from each partial hole for analysis. The total sample was split for the following analyses. Viscosity of the brine was measured before and after filtering out any biological components that may have been in solution or otherwise in order to assess whether or not extracellular carbon has an effect on fluid flow in sea ice. What was not used for viscosity measurements was used for chlorophyll, extra-cellular carbon and bacterial analysis to gain a sense of the level and type of biology and biological compounds in the brine to then be compared to the measured physical properties. The biological analysis will be carried out at the university of Tasmania by Sarah Ugalde. On many of these samples the complex permittivity of the brine was also measured and the data can be found in the Relative_Permitivity_of_Brine folder with each sample corresponding in core number. For info on the permittivity measurements please see the metadata in that folder.

This indicator is no longer maintained, and is considered OBSOLETE. INDICATOR DEFINITION Measurements of sea surface salinity in the Southern Ocean. Measurements are averaged over latitude bands: 40-50 deg S, 50-60 deg S, 60 deg S-continent. TYPE OF INDICATOR There are three types of indicators used in this report: 1.Describes the CONDITION of important elements of a system; 2.Show the extent of the major PRESSURES exerted on a system; 3.Determine RESPONSES to either condition or changes in the condition of a system. This indicator is one of: CONDITION RATIONALE FOR INDICATOR SELECTION Australian and Antarctic climate and marine living resources are sensitive to the distribution of ocean salinity. Sea surface values are relatively easy to monitor, and therefore can be used as a relevant indicator of the state of the ocean environment. The information provided by long records of sea surface salinity is needed to detect changes in the Southern Ocean resulting from climate change; to test climate model predictions; to develop an understanding of links between the Ocean and climate variability in Australia; and for sustainable development of marine resources. DESIGN AND STRATEGY FOR INDICATOR MONITORING PROGRAM Spatial scale: Southern Ocean: 40 deg S to the Antarctic continent Frequency: Monthly averages over summer Measurement technique: Measurements of sea surface salinity from Antarctic supply ships. RESEARCH ISSUES Sea surface salinity has not been previously used as a spatially averaged environmental indicator. Some experimentation with past data are required to define the most appropriate averaging strategy. New technologies like profiling Argo floats need to be exploited to provide better spatial and temporal coverage of salinity in the Southern Ocean. LINKS TO OTHER INDICATORS Sea surface temperature Sea ice extent and concentration Chlorophyll concentrations concentrations

The salinity of seawater at four sites around Casey was recorded during summer 2003/04 by a salinity probe (TPS Australia, WP-84 Conductivity Meter) attached to experimental mesocosms suspended below the sea ice. Data are salinity in parts per thousand (ppk) automatically logged every 30 minutes over the two two week long runs of the experiment. The period over which data were recorded varies between sites and is fragmentary within these periods at some sites due to power lose to the loggers caused by faulty batteries and adverse weather conditions. Mesocosms were suspended two to three metres below the bottom edge of the sea ice through a 1 metre diameter hole and were periodically raised to the surface for short periods (~1 hour). Mesocosms were deployed at Brown Bay Inner (S66 16.811 E110 32.475), Brown Bay Outer (S66 16.811 E110 32.526), McGrady Cove (S66 16.556 E110 34.392) and O'Brien Bay 1 (S66 18.730 E110 30.810). This experiment was part of the short-term biomonitoring program for the Thala Valley Tip Clean-up at Casey during summer 2003/04. These data were collected as part of ASAC project 2201 (ASAC_2201 - Natural variability and human induced change in Antarctic nearshore marine benthic communities). See also other metadata records by Glenn Johnstone for related information.

This dataset contains data resulting from the measurement of brine samples extracted from the sea-ice during the 2012 SIPEX 2 (Sea Ice Physics and Ecosystems Experiment) marine science voyage. The Brine was collected from partially drilled holes in the ice using suction. In some of these cases the brine analysed came from holes which correspond to permeability measurements. In these cases a core number is associated with the brine data which will correspond to the core number in the permeability data set. Brine was also made on the ship by repeatedly freezing sea water collected from site 8. Measurements of the electrical permittivity of the brine were measured from 200MHz-4GHz with varying temperature and salinity. The measurements were carried out using the FieldFox portable network analyser from Agilent technologies along with the Agilent 85070e high temperature dielectric probe. Typically the brine was cooled and measured as the temperature changed over time once removed from a freezer. Some samples were measured before and after filtering out any biology that may have been present to see any biological effect on the electrical properties of the brine, in particular any effect extra cellular carbon may have. Measurements of the biology in the brine were performed by Sarah Ugalde please refer to the biophysical folder for further information and the data. The actual permittivity measurements can be found in the Brine_Frequency_Temp Excel file. In the file each set of measurements has its own tab. Each measurement has a temperature and salinity associated with it. For a variability study measurements were repeated on some samples in which case the tab contains the sample name as well as an index indicating which repetition the data corresponds to. For example Core 85 6 would be the 6th measurement for core 85. You will also find the Excel file Brine_Calibration_Record which logs each calibration preformed before each measurement. The calibration for a given brine measurement has the same name as that brine measurement so that they can be matched. The permittivity measurements for each frequency, salinity and temperature are given in the real (e') and imaginary part (e").

The dataset lists key biogeochemical parameters measured in sea ice during the SIPEX2 voyage, including dissolved and particulate iron and other trace metals, macronutrients (silicic acid, nitrates+nitrite, phosphoric acid and ammonium), iron binding organic ligands, dissolved and particulate organic carbon, Cholophylla, thermodynamics (temperature, salinity, brine volume and Rayleigh number). All sampling bottles and equipment were decontaminated using trace metal clean techniques. Care was taken at each site to select level ice with homogeneous snow thickness. At all the stations, the same sampling procedure has been used : Firstly, snow was collected using acid cleaned low density polyethylene (LDPE) shovels and transferred into acid-cleaned 3.8 l LDPE containers (Nalgene). Snow collected was analysed for temperature, salinity, nutrients, unfiltered and filtered metals. Snow thickness was recorded with a ruler. Ice cores were collected using a non-contaminating, electropolished, stainless steel sea ice corer (140 mm internal diameter, Lichtert Industry, Belgium) driven by an electric power drill. Ice cores were collected about 10 cm away from each other to minimise between-core heterogeneity. A first core was dedicated to the temperature, salinity and Chlorophyll a (Chla). To record temperature, a temperature probe (Testo, plus or minus 0.1 degrees C accuracy) was inserted in holes freshly drilled along the core every 5 to 10 cm, depending on its length. Bulk salinity was measured for melted ice sections and for brines using a YSI incorporated Model 30 conductivity meter. Chla is processed on board using a 10 AU fluorometer (turner Designs, sunnyvale California). The total length of this core is cut in sections of 7 cm. The second core is dedicated to the POC/PON (Particulate Organic Carbon/ Particulate Organic Nitrogen), DOC (Dissolved Organic Carbon) and nutrients. Six sections of 7 cm were sub-sampled from this core. The six sections were chosen so that two top, two intermediate and two basal sections. Two cores are taken for the trace metal analysis. Those cores were directly triple bagged in plastic bags (the inner one is milli-Q washed) and frozen at -20degrees C until analysis at the laboratory. Brine samples were collected by drainage from “sack holes”. Brines and under ice seawater (~1 m deep) were collected in 1 l Nalgene LDPE bottles using an insulated peristaltic pump and acid cleaned C-flex tubing (Cole Palmer). All samples were then transported to the ship as quickly as possible to prevent further freezing. Samples were used to analyse unfiltered and filtered metals, Chla, POC/PON, nutrients and DOC. Filtration for filtered metals was completed on board using a peristaltic pump and a 0.2 microns cartridge filter. All the unfiltered and filtered metals collected were acidified (2 ppt HCl seastar) and stored at room temperature until analysis at the laboratory. Nutrients, DOC and filters for POC/PON were stored frozen at -20 degrees C until analysis at Analytical Service Tasmania, Hbart. Chla filtrations and analysis were completed on board. The file "SIPEX2 sea ice data" lists key biogeochemical parameters in sea ice cores, snow, brine and underice seawater (1m depth) collected during the SIPEX2 voyage (64.26-65.15S/116.44-120.58E) carried out between the 26th of september and 29th of october 2012. The acid-cleaning protocols for sample bottles and equipment followed the guidelines of GEOTRACES (www.geotraces.org). Contamination-free ice coring equipment developed by Lannuzel et al. (2006) was used to collect ice cores. Ice cores were triple bagged and stored at -18 degrees C until further processing in the home laboratory. Ice cores were then sectioned under a class-100 laminar flow hood (AirClean 600 PCR workstation, AirClean System) using a medical grade stainless steel bonesaw (Richards Medical), thouroughly rinsed with ultra-high purity water (18.2 MO), and ice sections were then allowed to melt at ambient temperature in acid-cleaned 3 L Polyethylene (PE) containers. Melted sea-ice sections were then homogenized by a gentle shake and filtered through 0.2 microns pore size polycarbonate filters (Sterlitech, 47 mm diameter) using Teflon(R) perfluoroalkoxy (PFA) filtration devices (Savillex, USA) connected to a vacuum pump set on less than 2 bar to obtain the particulate (greater than 0.2 microns) and dissolved (less than 0.2 microns) metal fractions. The collected filtrates (less than 0.2 microns) were acidified to pH 1.8 using Seastar Baseline(R) HCl (Choice Analytical) and stored at ambient temperature until analysis in the home laboratory. The filters retaining the particulate material were stored frozen in acid-clean petri dishes until further processing. Standard physico-chemical and biological parameters such as sea-ice and snow thicknesses, in situ ice temperature, sea-ice and brine salinities, ice texture, chlorophyll a (Chla), macro-nutrients (nitrate+nitrite (NOx), phosphate (PO43-), silicic acid (Si(OH)4-) and ammonium (NH4+)), dissolved organic carbon (DOC), and particulate organic carbon and nitrogen (POC and PON) were also determined in each sample at Analytical Service Tasmania (Hobart, Australia) within 6 months of sample collection. Dissolved inorganic nutrients were determined using standard colorimetric methodology (Grasshoff et al., 1983) as adapted for flow injection analysis using an auto-analyzer. Theoretical brine volume fractions (Vb/V) were calculated using in situ ice temperatures and bulk ice salinities and relationships from Cox and Weeks (1983). The full ice core length was examined under crossed-polarised light to identify the texture (i.e., columnar vs granular) according to the method of Langway (1958). Preparation of the thin sections took place in a container kept at -25 degrees C. The thin sections were obtained by cutting vertical sections of about 6 mm thick using a band saw. Ice sections were then thinned down using a microtome blade to reach a final thickness of 3 - 4 mm and observed under cross-polarized lights The acidified filtrates were diluted 5 times, using 2 % v:v ultrapure HNO3 (Seastar Baseline, Choice Analytical) and dissolved metals concentrations were determined directly using sector field inductively coupled plasma magnetic sector mass spectrometry (SF-ICP-MS; Element 2) following the method described in Lannuzel et al. (2014). Filters retaining particulate material (greater than 0.2 microns) were digested in a mixture of strong, ultrapure acids (750 micro litres 12N HCl, 250 microlitres 40% HF, 250 microlitres 14N HNO3) in 15 mL Teflon(R) perfluoroalkoxy (PFA) (Savillex, USA) on a Teflon coated graphite digestion hot plate housed in a bench-top fume hood (all DigiPREP from SCP Science, France) coupled with HEPA(R) filters to ensure clean air input at 95 degrees C for 12 h, then dry evaporated for 4 h and re-suspended in 2 % v:v HNO3 (Seastar Baseline, Choice Analytical). The procedure was applied to filter blanks and certified reference materials BCR-414 and MESS-3 to verify the recovery of the acid digestion treatment. The concentrations of particulate metals were then determined by SF-ICP-MS (Bowie et al., 2010). Results for procedural blanks, limits of detection and certified reference materials were found fit for purpose. The file "SIPEX2 TMR data" lists macro-nutrients concentrations, as well as dissolved iron concentrations collected using a Trace Metal Rosette (TMR) deployed over 1000m depth in the sea ice zone. Dissolved iron (DFe) and iron in the 2+ redox state (FeII) in nanomoles per Litre (nmol/L) were measured onboard using FIA-CL technique explained in Schallenberg et al (2015). Standard deviation associated with the analysis of the samples is indicated by "SD". Dissolved Fe(III): Dissolved Fe in this study is operationally defined as the Fe fraction that passes through a 0.2 microns filter. A modified flow injection analysis (FIA) method was used to measure dFe that relies on the detection of Fe(III) with the chemiluminescent reagent luminol (de Jong et al., 1998; Obata et al., 1993). Samples and standards were treated with hydrogen peroxide (H2O2; final concentration = 10 micro mols) at least 1 hour prior to measurement to oxidize any Fe(II) that might be present (Lohan et al., 2005). The system buffers the samples in-line to pH = 4 before passing them for 3 minutes through a pre-concentration column packed with 8-hydroxyquinoline chelating resin (8-HQ). A solution of 0.3 M HCl (Seastar) then elutes Fe(III) from the resin and mixes with 0.8 M ammonium hydroxide (NH4OH), 0.1 M H2O2 and 0.3 mM luminol containing 0.3 mM triethylenetetramine (TETA) and 0.02 M sodium carbonate (Na2CO3), yielding an optimum luminol chemiluminescence reaction pH of 9.5. The resulting solution is passed through a ~5 m mixing coil maintained at 35 degrees C before being pumped to the flow cell mounted in front of a photo-detector. System blanks were 0.014 plus or minus 0.004 nM, yielding a detection limit (3 x blank standard deviation) of 0.013 nM. Results for SAFe reference materials for Fe were in good agreement with consensus values (see Table 1). Dissolved Fe(II): Fe(II) was determined by luminol chemiluminescence detection following the approach of Hansard and Landing (2009) but without sample acidification. Sampling began within minutes after the first Niskin bottle (always from the surface) arrived in the clean container. Samples were analyzed within 2 minutes of filtration and were pumped simultaneously with the luminol reagent into a spiral flow cell made of flexible Tygon(TM) tubing (ID = 0.7 mm) that was mounted in front of a photomultiplier tube (Hamamatsu H9319-01) in a custom-made light-tight box. Flow rates for luminol and sample were ~4.5 mL/min. The photomultiplier tube was operated at 900 V with a 200 ms integration time. Photon counts were recorded using FloZF software (GlobalFIA) and were averaged over 10 second intervals with 5 replications for each sample and standard. The relative standard deviation of these repeat measurements was between 1 and 3%. The luminol recipe for 1 L reagent is as follows: 0.13 g luminol, 0.34 g Na2CO3, 40 mL concentrated NH4OH and 10-12 mL concentrated HCl (Seastar). This results in 0.75 mM luminol with 3.2 mM Na2CO3. The pH of the reagent is adjusted to ~10.0 with small amounts of NH4OH and HCl. It was found that luminol sensitivity increases with age, so batches were prepared well in advance and used up to 3 months later. Fe(II) calibration curves were obtained with Fe(II) standard additions in the range 0-100 pM. A 10 mM standard of ammonium iron(II) sulfate hexahydrate was prepared fresh in 0.1 M Seastar HCl and considered stable in the fridge for up to a month. From this stock solution, intermediate standards (50 micro mols and 50 nM) were prepared in 0.05 M Seastar HCl no more than 10 minutes prior to measurement. Standards were added to seawater that had been collected at earlier stations in the cruise and been left in the dark for greater than 24 hours. Previous investigators (e.g., Rose and Waite, 2001) have commented on the light-sensitivity of the luminol reagent, and it is therefore frequently stored in the dark.

Study location and test species Subantarctic Macquarie Island lies in the Southern Ocean, just north of the Antarctic Convergence at 54 degrees 30' S, 158 degrees 57' E. Its climate is driven by oceanic processes, resulting in highly stable daily and inter-seasonal air and sea temperatures (Pendlebury and Barnes-Keoghan, 2007). Temperatures in intertidal rock pools (0.5 to 2 m deep) were logged with Thermochron ibuttons over two consecutive summers and averaged 6.5 (plus or minus 0.5) degrees C. The island is relatively pristine and in many areas there has been no past exposure to contamination. To confirm sites used for invertebrate collections were free from metal contamination, seawater samples were taken and analysed by inductively coupled plasma optical emission spectrometry (ICP-OES; Varian 720-ES; S1) The four invertebrate species used in this study were drawn from a range of taxa and ecological niches (Figure 1). The isopod Limnoria stephenseni was collected from floating fronds of the kelp Macrosystis pyrifera, which occurs several hundred meters offshore. The copepod Harpacticus sp. and bivalve Gaimardia trapesina were collected from algal species in the high energy shallow, subtidal zone. Finally, the flatworm Obrimoposthia ohlini was collected from the undersides of boulders throughout the intertidal zone. We hypothesised L. stephenseni would be particularly sensitive to changes in salinity and temperature due to its distribution in the deeper and relatively stable subtidal areas, while O. ohlini would be less sensitive due to its distribution high in the intertidal zone and exposure to naturally variable conditions. We reasoned that the remaining two species, G. trapesina, and Harpacticus sp. were intermediate in the conditions to which they are naturally exposed and hence would likely be intermediate in their response. Test procedure The combined effect of salinity, temperature and copper on biota was determined using a multi-factorial design. A range of copper concentrations were tested with each combination of temperatures and salinities, so that there were up to 9 copper toxicity tests simultaneously conducted per species (Table 1). Experiments on L. stephenseni and Harpacticus sp. were done on Macquarie Island within 2 to 3 days of collection, during which they were acclimated to laboratory conditions. While, G. trapesina and O. ohlini were transported by ship to Australia in a recirculating aquarium system and maintained in a recirculating aquarium at the Australian Antarctic Division in Hobart, both at 6 degreesC. These two taxa were used in experiments within 3 months of their collection. A limited number of G. trapesina and O. ohlini were available, resulting in fewer combinations of stressors tested. Controls for the temperature and salinity treatments were set at ambient levels of 35 plus or minus 0.1 ppt and 5.5 to 6 degreesC for all species. The lowered control temperature for the bivalve reflected the cooler seasonal temperatures at time of testing and lower position within the intertidal. Previous tests conducted under these ambient conditions provided information on the ranges of relevant copper concentrations, appropriate test durations, and water change regimes for each taxon (Holan et al., 2017, Holan et al., 2016b). From these previous studies, we determined that a test duration of 14 d was sometimes required with 7 d often being the best outcome for most species due to high control survival and sufficient response across concentrations. The bivalve G. trapesina was an exception to this due to unfavourable water quality after 3 days in previous work (Holan et al., 2016). For the other three species, this longer duration for acute tests, compared to tests with tropical and temperature species (24 to 96 h) was consistent with previous Antarctic studies that have required longer durations in order to elicit an acute response in biota (King and Riddle, 2001, Marcus Zamora et al., 2015, Sfiligoj et al., 2015). Experimental variables (volume of water, density of test organisms, copper concentrations, temperatures and salinities) differed for each experiment due to differences between each species (Table 1). The temperature increases that were tested (2 to 4 degreesC) reflected the increased sea and air temperatures predicted for the region tested by 2100 (Collins et al., 2013). Treatments were prepared 24 h prior to the addition of animals. Seawater was filtered to 0.45 microns and water quality was measured using a TPS 90-FL multimeter at the start and end of tests. Dissolved oxygen was greater than 80% saturation and pH was 8.1 to 8.3 at the start of tests. All experimental vials and glassware were washed with 10% nitric acid and rinsed with MilliQ water three times before use. Salinity of test solutions was prepared by dilution through the addition of MilliQ water. Copper treatments using the filtered seawater at altered salinities were prepared using 500mg/L CuSO4 (Analytical grade, Univar) in MilliQ water stock solution. Samples of test solutions for metal analysis by ICP-OES were taken at the start and end of tests (on days 0 and 14). Details of ICP-OES procedures are described in the Supplemental material (S4). Samples were taken using a 0.45 µm syringe filter that had been acid and Milli-Q rinsed. Samples were then acidified with 1% diluted ultra-pure nitric acid (65% Merck Suprapur). Measured concentrations at the start of tests were within 96% of nominal concentrations. In order to determine approximate exposure concentrations for each treatment, we averaged the 0 d and 14 d measured concentrations (Table 1). Tests were conducted in temperature controlled cabinets at a light intensity of 2360 lux. At the Macquarie Island station a light-dark regime of 16:8 h was used to mimic summer conditions. In the laboratories in Kingston, Australia, a 12:12 h regime was used to simulate Autum light conditions (as appropriate for the time of testing). Test individuals were slowly acclimated to treatment temperatures over 1 to 2 h before being added to treatments. Temperatures were monitored using Thermochron ibutton data loggers within the cabinets for the duration of the tests. Determination of mortality of individuals differed for each taxon. Mortality was recorded for Gaimardia trapesina when shells were open due to dysfunctional adductor muscles; for Obrimoposthia ohlini when individuals were inactive and covered in mucous; for Limnoria stephenseni when individuals were inactive after gentle stimulation with a stream of water from a pipette; and for Harpacticus sp. when urosomes were perpendicular to prosomes (as used in other studies with copepods; see Kwok and Leung, 2005). All dead individuals were removed from test vials.

Motivation: One of the characteristics of this voyage is that we have long ice stations which last for a few days. Taking this opportunity, we decided to examine the diurnal change of snow properties at the fixed snow pit site. Since this measurement was not included in the original plan, Time interval was a bit variable from 3 hours to 5 hours depending on the progress of the other work. Observation items: Snow thickness, Temperature profile (every 3 cm), Grain size, Grain shape, Snow density, Hardness, Salinity Instruments: Folding scales, Spatula, Thermometer, Snow sampler, Magnifying glass, Salinometer Information pertaining to the dataset: Time - recorded in local time Hs - snow depth in cm Cloud measurements - oktas Water level - distance between snow surface and surface seawater in cm Depth - depth of the individual layer referenced to snow/ice interface (upper column) or snow surface (lower column) in cm Ta - air temperature in degrees celsius DH, FC, PP, DF, RG stand for Depth hoar, Faceted crystals, Precipitation particles, Decomposing and fragemented precipitation particles, Rounded grains - according to "The International Classification for Seasonal Snow on the Ground" (Colbeck et al., 1990). Weight - g Mid-depth - cm

This dataset contains routine measurements of snow and ice thickness, and snow-ice interface temperature, at 1m intervals along standard transects; snow property characterisation in snow pits measured at 0m, 50m and 100m along the transects; and sea ice cores acquired at various locations both along the transects and elsewhere on ice station floes during the 2012 SIPEX 2 marine science voyage. Ice temperature information is acquired from the cores, which are taken on-board for further analysis. The latter includes thin-section analysis of sea-ice stratigraphy and crystallography at -20C within the freezer lab on-board the ship. The cores are then cut up into 5cm sections and melted for analysis of salinity and stable oxygen isotopes. Observation items: Snow: - Thickness - Temperature profile (every 3 cm) - Snow-ice interface temperature at 1m intervals along the 100m transects - Grain size - Grain shape - Density - Hardness - Salinity - Stable oxygen isotope Ice: - Thickness - Freeboard - Draft - Temperature - Salinity - Stable oxygen isotope - Crystallography and texture - Density Instruments: Snow: Folding scales, Spatula, Thermometer, Snow sampler, Magnifying glass, Salinometer, Temperature and thickness probes, scales Ice: Drills, corers, ice-thickness tape measures, thermometer, salinometer, band-saw, cross-polarising filter, scales The data are recorded in log books (scanned copies are included in this dataset) and have been transferred into the standard AAD sea-ice database templates (in excel format) for each station.

Oceanographic measurements were conducted on and around the Antarctic shelf in the vicinity of the Mertz Glacier during the southern summer of 2007/2008, on Aurora Australis voyage au0803, V3 2007/2008. Data were collected as part of the CASO (oceanography) and CEAMARC (fishing) programs. The CASO program included occupation of the southern portion of the SR3 transect, plus additional transects down the slope. A total of (130) CTD vertical profile stations were taken, most to within 15 m of the bottom. Over (1400) Niskin bottle water samples were collected for the measurement of salinity, dissolved oxygen, nutrients, CFCs, dissolved inorganic carbon, alkalinity, oxygen-18, germanium, and biological parameters, using a 24 bottle rosette sampler. Full depth current profiles were collected by a lowered acoustic Doppler profiler (LADCP) attached to the rosette package, while near surface current data were collected by a ship mounted ADCP. Additional CTD profiles were taken at 2 subantarctic sites on the transit south. An array of 4 current meter and thermosalinograph moorings were deployed across a basin outflowing from the Mertz Polynya region.

Taken from the accompanying report: Oceanographic measurements were collected aboard the Aurora Australis on cruise au0806 (voyage 6 2007/2008, 22nd March 2008 to 17th April 2008). This cruise completed the CASO oceanographic program begun on the CEAMARC cruise (au0803, voyage 3 2007/2008), with a full occupation of the SR3 transect between Antarctica and Tasmania. CASO program objectives were: 1. to measure changes in water mass properties and inventories throughout the full ocean depth between Australia and Antarctica along 140oE (the CLIVAR/WOCE repeat section SR3), as part of a multi-national International Polar Year program to obtain a circumpolar snapshot of the Southern Ocean in austral summer 2007-8; 2. to estimate the transport of mass, heat and other properties south of Australia, and to compare results to previous occupations of the SR3 line and other sections in the Australian sector; 3. to deploy moorings near the Adelie Depression (142-145oE) as part of a joint Australia-France-Italy program to monitor changes in the properties and flow of Adelie Land Bottom Water; 4. to identify mechanisms responsible for variability in ocean climate south of Australia. The CASO program (with a full occupation of the SR3 transect) was originally scheduled for a single cruise. The shipping schedule was re-arranged following an unexpected period in drydock, due to a problem with the ship's thrusters, and as a result the CASO program was split over the two cruises. Several of the southern stations occupied on the first cruise au0803 were repeated on the second cruise au0806, to minimise the impact on the data set of the time gap between the cruises. A total of 131 CTD vertical profile stations were taken on au0803, and 73 CTD station were taken on au0806, most to within 20 metres of the bottom. During the 2 cruises, over 2900 Niskin bottle water samples were collected for the measurement of salinity, dissolved oxygen, nutrients (phosphate, nitrate+nitrite and silicate), 18O, CFC's, dissolved inorganic carbon, alkalinity, 14C, dissolved organic carbon, density (i.e. analysis of the effect of water composition on water density), germanium/silica/boron isotopes, trace metals, neodymium, chlorophyll-a, cell counts, pigments, genetic analyses, and other biological parameters, using a 24 bottle rosette sampler. Full depth current profiles were collected by an LADCP attached to the CTD package, while upper water column current profile data were collected by a ship mounted ADCP. Data were also collected by the array of ship's underway sensors. This report describes the processing/calibration of the CTD data, and details the data quality. An offset correction is derived for the underway sea surface temperature and salinity data, by comparison with near surface CTD data. CTD station positions are shown in Figures 1 and 2, while CTD station information is summarised in Table 1. Mooring and drifter deployments/recoveries are summarised in Table 14. Mooring data from the Adelie Depression deployments are discussed in the mooring data reports Rosenberg (unpublished report, 2009) and Meijers (unpublished report, 2009). Further cruise itinerary/summary details can be found in the voyage leader reports (Australian Antarctic Division unpublished reports: Riddle, V3 2007/08 VL report; Rintoul, V6 2007/08 VL report). Hydrochemistry and CFC cruise reports are in Appendix 1 and Appendix 2. Details about the data are available in a readme file and a full report in the download file.