During the ice stations, measurements of the air CO2, concentration for CO2 flux between sea ice and atmosphere were made with the chamber technique. Air-sea ice CO2 fluxes were measured over the sea ice with semi-automated chambers. Sample air from the chamber is passed through Teflon tubes connected to non-dispersive infrared (NDIR) analyzer (Model 800, LICOR Inc., USA) that was connected to a system controller and data logger (Model 10x, Campbell Scientific Inc., USA), that controls the opening/closing of the chambers as well. During the observation period, the CO2 flux was measured under three different conditions or surface types: (1) a chamber was installed above snow; (2) over the bare ice after removing the snow; (3) slush layer after removing the snow and slush crystals. The CO2 concentration in the chamber was measured every 5 s during experiments lasting 20 minutes for each chamber. A one hour cycle of measurements therefore consist of three 20 minute periods from each chamber (i.e. surface type). Data available: excel files containing sampling station name for each spreadsheet, dates, sampling time and air CO2 concentration as output voltage from NDIR (to indicated as ppm we need to calculate, but, not yet done this process) in the air and chamber for CO2 flux measurement. Also see the record - SIPEX_II_Gas_Flux

Data acquisition: Samples were collected using a 1.5 metre diameter Ring net (150 micron metre mesh) with a wide cod-end on the base (volume approximately 40 Litres). Vertical trawls were to 20 m (unless otherwise specified). Deployment speed was determined by wave conditions with hauling speed at slowest possible speed available by the gantry (approximately than 2 meters per second). The net was rinsed with sea water before the cod-end was removed and the contents determined by observing a sub-sample under the light microscope. Appendicualrians were separated and preserved while the remaining contents of the cod-end were sieved through 120 micrometre mesh and preserved to be sorted more accurately on return to the laboratories. The appendicularians were quantified and sorted under light microscopes with additional randomly selected individuals being prepared for Scanning Electron Microscopy (SEM) imaging to enable identification to species level and some Oikopleura gaussica stomach's where dissected for SEM dietary analysis. Data processing: Data are being processed using 'statistica 6' (and possibly PRIMER or PATN) to determine correlations with physical parameters obtained from underway data, the CTD and the microbial biologist. Dataset Format: Database is an excel spreadsheet Parameters: Leg - identification number of southern bound legs Event number - deployment number Station - leg number . sample point number CTD - number of corresponding CTD (conductivity, Temperature Depth sample point) Date - date/month/year Time (UTC) Latitude Longitude NET (mesh (micro meters) type) - Net type and mesh size in micro meters (150) DEPTH (m) - vertical trawl depth APPENDICULARIANS - count of appendicularians from ship and laboratory based sorting Fritiliaria drygalski - count of Fritillaridae's from ship and laboratory based sorting Oiklopleura gaussica - count of Oikopleuridae's from ship and laboratory based sorting Alive - count of live appendicularians from ship based sorting SEM IMAGE - individual appendicularians and/or O. gaussica stomach SEM images have been taken SEM Stub number - stub number that is first two numbers of SEM images SAMPLE TYPE - BARCODE Zooplankton - cod-end contents sieved and preserved Appendicularians - sorted from cod-end Live - live appendicularians (now preserved) Other 1- samples that did not fit in to the above categories or additional samples for station Other 2- additional samples for station that did not fit in to the above categories This work was completed as part of ASAC projects 2655 and 2679 (ASAC_2655, ASAC_2679).

Data were collected during the 1997-1998 austral summer on voyages by the Aurora Australis and Southern Surveyor. Taken from the abstract of the referenced paper: Oceanographic processes in the subantarctic region contribute crucially to the physical and biogeochemical aspects of the global climate system. To explore and quantify these contributions, the Antarctic Cooperative Research Centre (CRC) organised the SAZ Project, a multidisciplinary, multiship investigation carried out south of Australia in the austral summer of 1997-1998. Here we present a brief overview of the SAZ Project and some of its major results, as detailed in the 16 papers that follow in this special section. The Southern Ocean plays an important role in the global oceanic overturning circulation and its influence on the carbon dioxide contents of the atmosphere. Deep waters upwelled to the surface are rich in nutrients and carbon dioxide. Air-sea interaction modifies the upwelled deep waters to form bottom, intermediate, and mode waters, which transport freshwater, oxygen, and carbon dioxide into the ocean interior. The overall effect on atmospheric carbon dioxide is a balance between outgassing from upwelled deep waters and uptake via both dissolution in newly formed waters (sometimes referred to as the solubility pump) and the transport of photosynthetically formed organic carbon to depth in settling particles (referred to as the biological pump). Determining the variations in the overturning circulation and the associated carbon fluxes in the past and their response to increased anthropogenic emissions of carbon dioxide in the future is essential to a full understanding of the controls on global climate. At present the upwelled nutrients are incompletely used. Low light in deep wind-mixed surface layers, lack of the micronutrient iron, and other factors restrict phtyoplankton production so that Southern Ocean surface waters represent the largest high-nutrient, low chlorophyll (HNLC) region in the world.

Metadata record for data from ASAC Project 133 See the link below for public details on this project. Surface carbon dioxide (CO2) observations are integral to understanding the role of the Southern Ocean in the global carbon cycle, and to developing reliable predictions of biogeochemical responses to altered climatic conditions. Carbon dioxide (CO2) observations made in surface waters of the Australian sector of the Southern Ocean between the years 1991 and 2002 were used to estimate the seasonal variability in the fugacity of CO2 (fCO2) and net air-sea carbon fluxes. The results showed a net annual uptake of CO2 by the surface ocean over the entire region. The greatest seasonal uptake and lowest fCO2 values were observed in Spring/Summer in the sub-Antarctic zone (SAZ: 44 degrees S-50 degrees S) and in the Seasonal Sea-ice Zone (SIZ: south of 62 degrees S). The seasonal maximum in uptake for these regions is consistent with increased phytoplankton biomass and shoaling mixed layers over the Spring/Summer period. The High Nutrient Low Chlorophyll waters between 50 degrees S and 62 degrees S, also had maximum uptake in summer, but less compared to the SAZ and SIZ regions. Winter surface waters were close to or slightly above equilibrium, with respect to atmospheric CO2. The reduced uptake in winter appeared due to deeper mixing, lower biomass, and air-sea CO2 exchange. The highest fCO2 values in Winter were observed under or near the seasonal sea-ice where entrainment of deeper CO2-rich waters and ice cover would maintain high surface fCO2 values. The smallest seasonal amplitude in the surface fCO2 and net air-sea fluxes was found from 51 degrees S to 54 degrees S, a region on the southern edge of the SAZ and between the North sub-Antarctic Front and North Polar Front. The uptake estimates derived from the data were in good agreement with the CO2 flux climatology of Takahashi (2002), except in the SAZ and SIZ where we observed greater and less uptake, respectively. Data for this project are available for download - the dataset consists of a data files, and some excel files, which provide further information about each data file (cruise, dates, etc). Furthermore, the column headings used in the data files are as follows: Cruise - name of the cruise which collected the data Date - UTC Time - in UTC Latitude - decimal Longitude - decimal Sst - Sea Surface Temperature in degrees C Teq - Temperature of surface water at which the CO2 measurement is made. Sal - Salinity Patm - atmospheric pressure in hectopascals Shipspd - ship speed in knots Windspd - wind speed in knots Winddir - wind direction in degrees xCO2 - Mole fraction of CO2 in air (dry) equilibrated with surface water and at equilibrator water temperature xCO2air - Mole fraction of CO2 in atmosphere, dry pCO2 - partial pressure of carbon dioxide in surface water

Metadata record for data from ASAC Project 2584 See the link below for public details on this project. The Southern Ocean plays a significant role in the biogeochemical cycling of sulphur due to high spring-summer fluxes of dimethylsulfide (DMS), particularly south of 60 degrees S. Recent DMS flux perturbation simulations have recently highlighted the key role of the SO between 50-70 degrees S in the DMS-climate feedback hypothesis [Gabric et al., 2003; Gabric et al., 2004]. This project examines the interactions and feedback between marine polar plankton and global climate through the use of biogeochemical and global climate models, and explores the sensitivity of climate to the current and future biogenic production of dimethylsulphide at polar latitudes. This was a modelling project, and as such did not collect any data of its own. Taken from the abstracts of the referenced papers: The global climate is intimately connected to changes in the polar oceans. The variability of sea ice coverage affects deep-water formations and large-scale thermohaline circulation patterns. The polar radiative budget is sensitive to sea-ice loss and consequent surface albedo changes. Aerosols and polar cloud microphysics are crucial players in the radioactive energy balance of the Arctic Ocean. The main biogenic source of sulfate aerosols to the atmosphere above remote seas is dimethylsulfide (DMS). Recent research suggests the flux of DMS to the Arctic atmosphere may change markedly under global warming. This paper describes climate data and DMS production (based on the five years from 1998 to 2002) in the region of the Barents Sea (30-35 degrees E and 70-80 degrees N). A DMS model is introduced together with an updated calibration method. A genetic algorithm is used to calibrate the chlorophyll-a (CHL) measurements (based on satellite SeaWiFS data) and DMS content (determined from cruise data collected in the Arctic). Significant interannual variation of the CHL amount leads to significant interannual variability in the observed and modelled production of DMS in the study region. Strong DMS production in 1998 could have been caused by a large amount of ice algae being released in the southern region. Forcings from a general circulation model (CSIRO Mk3) were applied to the calibrated DMS model to predict the zonal mean sea-to-air flux of DMS for contemporary and enhanced greenhouse conditions at 70-80 degrees N. It was found that significantly decreasing ice coverage, increasing sea surface temperature and decreasing mixed-layer depth could lead to annual DMS flux increases of more than 100% by the time of equivalent CO2 tripling (the year 2080). This significant perturbation in the aerosol climate could have a large impact on the regional Arctic heat budget and consequences for global warming. The response of oceanic phytoplankton to climate forcing in the Arctic Ocean has attracted increasing attention due to its special geographical position and potential susceptibility to global warming. Here, we examine the relationship between satellite derived (sea-viewing wide field-of-view sensor, SeaWiFS) surface chlorophyll-a (CHL) distribution and climatic conditions in the Barents Sea (30-35 degrees E, 70-80 degrees N) for the period 1998-2002. We separately examined the regions north and south of the Polar Front (~76 degrees N). Although field data are rather limited, the satellite CHL distribution was generally consistent with cruise observations. The temporal and spatial distribution of CHL was strongly influenced by the light regime, mixed layer depth, wind speed and ice cover. Maximum CHL values were found in the marginal sea-ice zone (72-73 degrees N) and not in the ice-free region further south (70-71 degrees N). This indicates that melt-water is an important contributor to higher CHL production. The vernal phytoplankton bloom generally started in late March, reaching its peak in late April. A second, smaller CHL peak occurred regularly in

Metadata record for data from ASAC Project 2518 See the link below for public details on this project. Global climate change will lead to a reduction in the duration and thickness of sea ice in coastal areas. We will determine whether this will lead to a decrease in primary production and food value to higher predators. Project objectives: Our primary objective is to determine what effect will declining sea ice cover have on Antarctic coastal primary production? Hypotheses to be tested A decrease in sea ice algal production will lead to a net reduction in total primary production. A decrease in sea ice will result in less water column stratification which will reduce the significance of phytoplankton blooms. Less sea ice will lead to a change in phytoplankton bloom composition away from diatoms towards un-nutritious nuisance blooms such as Phaeocystis Benthic microalgal production will increase Seaweed production will increase slightly A decrease in sea ice thickness will increase ice algal production (as they are generally light limited) Ice algae, benthic microalgae, and phytoplankton will acclimate to an elevated light climates by changing their photosynthetic efficiency and capacity Ice algae, benthic microalgae, and phytoplankton will acclimate to an altered light quality. To answer these questions we will also need to determine: What is the total annual primary production at coastal Antarctic sites; this consists of the contributions from the sea ice algal mats, benthic microalgal, seaweed and phytoplankton? What is the effect of major environmental variables, such as UV, salinity, currents oxygen toxicity, cloud cover, nutrient availability and temperature on production. What is the inter-annual variability in primary production? A broader scale issue that our data will contribute to providing answers to is the question What effect will changing primary production have on higher trophic levels? Taken from the 2009-2010 Progress Report: Progress against objectives: The 2009/10 field and laboratory season focused on the second of our primary questions, i.e. 'What is the effect of major environmental variables, such as UV, salinity, currents oxygen toxicity, cloud cover, nutrient availability and temperature on production'. In particular we focused on light and light transmission though the sea ice. The science program AAS2518 was executed at Casey station from 11 Nov to 5 Dec 2009. The project was split into a field and a lab-based component. In situ spectral light transmission data were collected on first year sea ice within the vicinity of Jack's Hut. Ice cores were collected and transported to the laboratory at Casey station for spectral attenuation profiles within sea ice, and for measurements of spectral absorption by particulate and dissolved organic matter. Overall, the program was successful: in situ sea-ice spectral transmission data was collected in combination with vertical profiles of absorption coefficients of particulate (algae and detritus) and dissolved organic matter. Samples for analysis of photosynthetic pigments were collected and shipped to Sydney. Their analysis is underway. Due to logistical issues associated with the collection and transport of sea ice cores, the protocol for vertical profiling of spectral attenuation was modified (see below) and analysis of the data is currently underway. The field component of the program was successful as spectral transmission data was collected for first year sea-ice, and the chosen site contained a thriving sea ice algal community for bio-optical measurements. It was initially planned to sample multiple sites offering a range of varying sea-ice thickness, but this was not possible during this campaign. Many sites in the vicinity of Casey station had already started to melt and break up, so that for logistical and safety reasons the area around Jack's hut was the only workable option. The field period instead spanned ~ 20 days during the melt period at Jack's,