This project used computer-based modelling and existing field data to analyse the production and cycling of dimethylsulphide (DMS) and predicted its role in climate regulation in the Antarctic Southern Ocean. From the Final Report: Aims (i) To calibrate an existing dimethylsulphide (DMS) production model in a section of the Antarctic Southern Ocean. (ii) To use the calibrated model to investigate the effect of GCM-predicted climate change on the production and sea-to-air flux of DMS under current and enhanced greenhouse climatic conditions. (iii) To provide regional assessments of the sign and strength of the DMS-climate feedback in the Southern Ocean. Characteristics of Study Region: Our study region extends from 60-65 degrees S, 123-145 degrees E in the Antarctic Southern Ocean, and was the site of a major biological study in the austral summer of 1996 (Wright and van den Enden, 2000). Field observations show that a short-lived spring-summer bloom event is typical of these waters (El-Sayed, 1988, Skerratt et al. 1995); however there can be high interannual variability in the timing and magnitude of the bloom (Marchant and Murphy, 1994). The phytoplankton community structure has been described by Wright and van den Enden (2000), who report maximum chlorophyll (Chl) concentrations during January-March in the range (1.0-3.4) microgL-1. During this survey, macronutrients did not limit phytoplankton growth. Thermal stratification of the mixed layer was strongly correlated with high algal densities, with strong subsurface Chl maxima (at the pycnocline) observed. The mixed layer depth determined both phytoplankton community composition and maximum algal biomass. Coccolithophorids (noted DMS producers) were favoured by deep mixed layers, with diatoms dominating the more strongly stratified waters. Pycnocline depth varied from 20-50 m in open water. Algal abundance appeared to be controlled by salp and krill grazing. Field data support the existence of seasonal DMS production in the Antarctic region. However, a large range in DMS concentrations has been reported in the open ocean , reflecting both seasonal and spatial variability (Gibson et al., 1990, Berresheim, 1987; Fogelqvist, 1991). Blooms of the coccolithophores, and prymnesiophytes such as Phaeocystis, form a significant fraction (~23%) of the algal biomass (Waters et al 2000). Concentrations of DMS in sea ice are reported to be very high (Turner et al. 1995) and may be responsible for elevated water concentrations during release from melt water (Inomata et al. 1997). Field measurements of dissolved DMS made in the study region have been summarised by Curran et al. (1998). DMS concentrations were variable in the open ocean during spring and summer (range: 0-22 nM), with the higher values recorded in the seasonal ice zone and close to the Antarctic continent. Zonal average monthly mean DMS in the study region have been estimated by Kettle et al. (1999). (See downloadable full report for reference list). A copy of the referenced publication is also available for download by AAD staff. It contains the modelling information.

Sediment cores were collected from the East Antarctic margin, aboard the Australian Marine National Facility R/V Investigator from January 14th to March 5th 2017 (IN2017_V01; Armand et al., 2018). This marine geoscience expedition, named the “Sabrina Sea Floor Survey”, focused notably on studying the interactions of the Totten Glacier with the Southern Ocean through multiple glacial cycles. The cores were collected using a multi-corer, allowing to sample the surface of the sediment (top ~ 30cm). The cores were then sliced every centimetre, wrapped up in plastic bags, and stored in the fridge. Radiocarbon (14-C) ages were measured to build an age model for future paleo-reconstructions. Sediment samples were pre-treated in the IMAS Sediment Lab (UTAS, Hobart, Australia). Samples (~ 2 g) from the multi-cores MC01, MC03 and MC06 were dried, ground and acidified with HCl for carbonate removal using sterilised beakers. Dried and ground samples were then packed into sterilised aluminium foil and sent to DirectAMS (Radiocarbon Dating Service, USA) for 14C analysis by Accelerator Mass Spectrometer (AMS). Results were corrected for isotopic fractionation with an unreported δ13C value measured on the prepared carbon by the accelerator. References L.K. Armand, P.E. O’Brien and On-board Scientific Party. 2018. Interactions of the Totten Glacier with the Southern Ocean through multiple glacial cycles (IN2017-V01): Post-survey report, Research School of Earth Sciences, Australian National University: Canberra.

Please also see the child records of this project for access to data. Attached to this record are the originally supplied datasets for 1997-1998, and also summary files and mooring diagrams supplied in 2012. Taken from the 2008-2009 Progress Report: Progress against objectives: The key to advancing the objective of understanding ocean processes controlling uptake of atmospheric CO2 is the ability to deploy moored autonomous samplers and sensors in Southern Ocean surface waters capable of quantifying seasonal cycles in biological and biogeochemical processes. Our effort in the last 12 months has focused on development of a robust mooring platform to carry these devices. We deployed two different engineering test designs, known as Pulse 5 Heavy and Pulse 5 Light. Both designs survived 6 months in the sea, including wave heights up to 12 meters, while transmitting mooring tensions, mooring accelerations, and GPS positions live to the internet (www.imos.org.au). Following this success we are preparing to deploy the next version of Pulse with scientific instruments to measure temperature, salinity, oxygen, and phytoplankton fluorescence. In addition we deployed a deep ocean mooring with time-series sediment traps to quantify sinking particle fluxes, and in-situ settling columns to determine particle sinking rates. Taken from the 2009/2010 Progress Report: Progress against objectives: Two voyages were awarded by the Australian Marine National Facility to use RV Southern Surveyor to service these Southern Ocean Time Series (SOTS) moorings in the 2009/10 season, and for this reason the shiptime awarded to this project by AAS was not needed and was relinquished. This arrangement will continue in 2010/11 for which the MNF has again awarded two voyages in September 2010 and April 2011. The fieldwork in 2009/10 was very successful: i) the SAZ deep sediment trap mooring was recovered in September 2009 and redeployed for recovery in September 2010. ii) the PULSE biogeochemistry mooring was deployed in September 2009 and functioned beautifully prior to recovery in March 2010 for servicing. It will be redeployed in September 2010. iii) the SOFS Southern Ocean Flux Station mooring was completed and deployed in March 2010 for recovery in April 2011, and redeployment in September 2011.

Amery Ice Shelf AM05 borehole drilled mid-December 2009. Sub-shelf water profiling measurements conducted over a period of a few days. Partial video recording of borehole walls and sea floor benthos. Collection of targeted ice core samples. Sediment sample collected from sea floor. Long term monitoring instruments installed (thermistors in ice, 3 x CTD in ocean cavity). This is a parent record - see the child records for further information. Some general readme documents are available for download from the provided URL.

Metadata record for data from ASAC Project 2592 See the link below for public details on this project. The Southern Ocean is one the most significant regions on earth for regulating the build up of anthropogenic carbon in the atmosphere, and the capacity for carbon uptake in the region could be altered by climate change. The project aims to use repeat ocean sections to detect anthropogenic carbon storage, identify key processes regulating the amount of storage, and to test models that predict future uptake. The data are broken down by season and voyage, and a word document providing further details about the project is also available as part of the download file.

Twenty-six marine and lacustrine sediment cores were taken from Windmill Islands during the 1998/99 season. They have been analysed for physical, chemical and biological parameters by a multidisciplinary team under ASAC project 1071. The download file contains 12 Excel spreadsheets of data.

This dataset contains the data collected during the RAPPLS (Radar, Aerial Photography, Pyrometer, and Laser Scanning system) flights that were undertaken as a part of the SIPEX II (Sea Ice Physics and Ecosystems Experiment II) Antarctic marine science voyage in September-November 2012. The RAPPLS project involved designing and using a system using a helicopter with mounted sensors to record data while flying over sea ice. The RAPPLS helicopter is an Aerospaciale AS 350 BA "Squirrel" helicopter with a range of scientific equipment mounted to it. These are generally imaging instruments that are used to derive snow and ice properties, such as roughness, surface elevation and skin temperature. The following is a list of instruments used and parameters measured: - 2-8 GHz frequency modulated continuous wave radar, measuring impedance differences between snow and sea ice; - Hasselblad H3D II 50 camera, taking aerial photographs at about 13 cm resolution every 3-5 seconds - Heitronics KT 19 pyranometer, measuring skin surface temperature - Riegl LMS Q240i-60 scanning LiDAR, measuring surface elevation of sea ice above sea level All data are geo-located with a combined inertial navigation and global positioning system, OxTS RT-4003. See Australian Antarctic Division Science Technical Support Project 07006 for detailed Engineering documents. Detailed flight information for each flight is available from WORD documents for each survey. Contained in this dataset are the following files: - A MS Word log file for all flights; - A QGIS map file showing all flights; - A folder for each flight containing the following (named - Date - Fxx - Mission: - A Microsoft Word document explaining the flight intentions, issues, and outcomes (flight log); - A folder of the photos taken by the Hasselblad camera; - A folder of raw and processed INS data: - RD files, which are raw INS and can be opened RT_PostProcess software; - PNG Files showing flight track, created with RT_View software based on NCOM files resulting from RT_PostProcess; - A folder with log files for Errors, Events, LaserScanner, Pyrometer, and INS. This folder also includes Q24 file of raw laser scanner data (purpose written software to analyse the data is available with the 2008 data set); - A folder with time synchronisation log file.

Sediment cores were collected from the East Antarctic margin, aboard the Australian Marine National Facility R/V Investigator from January 14th to March 5th 2017 (IN2017_V01; Armand et al., 2018). This marine geoscience expedition, named the “Sabrina Sea Floor Survey”, focused notably on studying the interactions of the Totten Glacier with the Southern Ocean through multiple glacial cycles. The cores were collected using a multi-corer (MC) and a Kasten corer (KC). The MC were sliced every centimetre, wrapped up in plastic bags, and stored in the fridge. The KC was sub-sampled using an u-channel; and sliced every centimetre once back the home laboratory (IMAS, UTAS, Hobart, Australia). This dataset presents concentrations of major and trace elements measured in bulk multi-cores sediment samples collected during the IN2017_V01 voyage. The data include the sampling date (day/month/year), the latitude and longitude (in decimal degrees), the seafloor depth (in meter), the sediment core ID, the sediment depth (in cm), and the concentrations (in ppm or μg/g) of a suite of elements. This dataset presents concentrations of major and trace elements measured in bulk sediment samples collected during the IN2017_V01 voyage. The data include the sampling date (day/month/year), the latitude and longitude (in decimal degrees), the seafloor depth (in meter), the sediment core ID (KC14), the sediment depth (in cm), and the concentrations (in ppm or μg/g) of a suite of elements. About 200 mg of dried and ground sediment were weighed into a clean Teflon vial and oxidized with a mixture of concentrated HNO3 and 30% H2O2 (1:1). Samples were then digested in open vials using an acid mixture comprising 10 mL HNO3, 4 mL HCl, and 2 mL HF, at 180°C until close to dryness. Digested residues were converted to nitric form before being oxidised with a mixture of 1 mL HNO3 and 1 mL HClO4 at 220°C until fully desiccated. Samples were finally re-dissolved in 4 mL 7.5 M HNO3. A 400 μL aliquot was removed from the 4 mL digest solution and diluted ~2500 times in 2% HNO3 for trace metals analysis by Sector Field Inductively Coupled Mass Spectrometry (SF-ICP-MS, Thermo Fisher Scientific, Bremen, Germany) at the Central Science Laboratory (UTAS, Hobart, Australia). Indium was added as internal standard (In, 100 ppb). 88Sr, 89Y, 95Mo, 107Ag, 109Ag, 111Cd, 133Cs, 137Ba, 146Nd, 169Tm, 171Yb, 185Re, 187Re, 205Tl, 208Pb, 232Th, 238U, 23Na, 24Mg, 27Al, 31P, 32S, 42Ca, 47Ti, 51V, 52Cr, 55Mn, 56Fe, 59Co, 60Ni, 63Cu and 66Zn were analysed using multiple spectral resolutions. Element quantification was performed via external calibration using multi-element calibration solutions (MISA suite, QCD Analysts, Spring Lake, NJ, USA). Raw intensities were blank and dilution corrected. References L.K. Armand, P.E. O’Brien and On-board Scientific Party. 2018. Interactions of the Totten Glacier with the Southern Ocean through multiple glacial cycles (IN2017-V01): Post-survey report, Research School of Earth Sciences, Australian National University: Canberra.