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. Taken from the abstracts of the referenced paper: We developed and applied a one-dimensional (z) biophysical model to the Subantarctic Zone (SAZ) and the Polar Frontal Zone (PFZ) to simulate seasonal phosphate export production and resupply. The physical component of our model was capable of reproducing the observed seasonal amplitude of sea surface temperature and mixed layer depth. In the biological component of the model we used incident light, mixed layer depth, phosphate availability, and estimates of phytoplankton biomass from the Sea-viewing Wide Field-of-view Sensor to determine production and tuned the model to reproduce the observed seasonal cycle of phosphate. We carried out a series of sensitivity studies, taking into account uncertainties in both physical fields and biological formulations (including potential influence of iron limitation), which led to several robust conclusions (as represented by the ranges below). The major growing season contributed 66-76% of the annual export production in both regions. The simulated annual export production was significantly higher in the PZF (68-83 mmol P m-2) than in the SAZ (52-61 mmol P m-2) despite the PFZ's having lower seasonal nutrient depletion. The higher export production in the PFZ was due to its greater resupply of phosphate to the upper ocean during the September to March period (27-37 mmol P m-2) relative to that in the SAZ (8-15 mmol P m-2). Hence seasonal nutrient depletion was a better estimate of seasonal export production in the SAZ, as demonstrated by its higher ratio of seasonal depletion/export (64-78%) relative to that in the PFZ (34-47%). In the SAZ, vertical mixing was the dominant mechanism for supplying phosphate to the euphotic zone, whereas in the PFZ, vertical mixing supplied only 37% of the phosphate to the euphotic zone, whereas in the PFZ, vertical mixing supplied only 37% of the phosphate to the euphotic zone and horizontal transport supplied the remaining 63%.

Environmental descriptors that are available for the study area (-180 degrees W/+180 degrees E; -45 degrees/-78 degrees S) and for the following periods: 1955-1964, 1965-1974, 1975-1984, 1985-1994, 1995-2012. They were compiled from different sources and transformed to the same grid resolution of 0.1 degree pixel. We also provide future projections for environmental descriptors established based on the Bio-Orable database (Tyberghein et al. 2012). They come from IPCC scenarii (B1, AIB, A2) for years 2100 and 2200 (IPCC, 4th report).

This is the CTD and Niskin bottle data set from the RV Tangaroa cruise tan0704, 7th Mar 2007 to 29th Mar 2007, along the Macquarie Ridge. This was the deployment cruise for the Macquarie Ridge mooring array. Dissolved oxygen data have been removed from this data set (oxygen bottle data never analysed). There were a total of 75 CTD casts on this cruise.

The absolute abundances (cells per ml) of 22 hard-shelled phytoplankon taxa (comprised of species, genera or higher taxonomic groups) estimated from Scanning Electron Microscope survey of 52 samples collected through 11 austral spring-summers (2002/3 to 2012/13) (part of the L' Astrolabe collection) from the seasonal ice zone of the Southern Ocean (between latitude 62 and 64.4 degrees south, and longitude 135.8 and 150 degrees east) also included are environmental covariables for each sample: three constructed SAM indices, SST, Salinity, NOx, PO4, SiO4, and the sampling date, time, and location. Fifty-two surface-water samples were collected from the seasonal ice zone (SIZ) of the Southern Ocean (SO) across 11 consecutive austral spring-summers from 2002/03 to 2012/13. The samples were collected aboard the French re-supply vessel MV L’Astrolabe during resupply voyages between Hobart, Tasmania, and Dumont d’Urville, Antarctica between the 20th October and the 1st March. Most samples were collected from ice-free water, although some were collected south of the receding ice-edge. The sampled area was in the high latitude SO (Figure 1b) in the south-east corner of the Australian Antarctic Basin, spanning 270 km of latitude between 62°S and 64.5°S, and 625km of longitude between 136°E and 148°E. The area lies greater than 100 km north of the Antarctic continental shelf, in waters greater than 3,000 m depth. Samples were obtained from the clean seawater line of the re-supply ship from around 3 m depth. Each sample represented 250 ml of seawater filtered through a 25 mm diameter polycarbonate-membrane filter with 0.8 µm pores (Poretics). The filter was then rinsed with two additions of approximately 2 ml of MilliQ water to remove salt, then air dried and stored in a sealed container containing silica gel desiccant. Samples were prepared for scanning electron microscope (SEM) survey by mounting each filter onto metal stubs and sputter coating with 15 nm gold or platinum. Only organisms possessing hard siliceous or calcareous shells were sufficiently well preserved through the sample preparation technique that they could be identified by SEM, and included diatoms, coccolithophores, silicoflagellates, Pterosperma, parmales, radiolarians, and armoured dinoflagellates. The composition and abundance the phytoplankton community of each sample was determined using a JEOL JSM 840 Field Emission SEM. Cell numbers for each phytoplankton taxon were counted in randomly selected digital images of SEM fields taken at x400 magnification (Figure 2). Each image represented an area of 301 x 227 µm (0.068 mm2) of each sample filter, which was captured at a resolution 8.5 pixels/µm. A minimum of three SEM fields were assessed for each sample, with more fields assessed when cell densities were lower. On average, 387 cells were counted for each sample. Taxa were classified with the aid of Scott and Marchant (2005), Tomas (1997), and expert opinion. Cell counts per image were converted to volume-specific abundances (cells/ml) by dividing by 0.0348 ml of sea-water represented by each image. A total of 19,943 phytoplankton organisms were identified and counted: 18,872 diatoms, 322 Parmales, 173 coccolithophores, 81 silicoflagellates, and 45 Petasaria. A total of 48 phytoplankton taxa were identified, many to species level. Because the diatoms Fragilariopsis curta (Van Heurck) Hustedt and F. cylindrus (Grunow ex Cleve) Helmcke and Krieger could not be reliably discriminated at the microscope resolution employed, they were pooled into a single taxa-group. Other taxa were also grouped, namely Nitzschia acicularis (Kützing) W.Smith with N. decipiens Hustedt to a single group, and discoid centric diatoms of the genera Thalassiosira, Actinocyclus and Porosira to another. Rare species, with maximum relative abundance less than 2%, were removed from the data prior to analysis as they were not considered to be sufficiently abundant to warrant further analysis (Webb and Bryson 1972, Taylor and Sjunneskog 2002, Swilo et al. 2016). After pooling taxa and deleting rare taxa, twenty-two taxa and taxonomic-groups (species, groups of species and families) remained to describe the composition of the phytoplankton community. Phytoplankton abundances were related to a range of environmental covariates available at the time of sampling. These included the SAM, sea surface temperature (SST), salinity, time since sea ice cover (DaysSinceSeaIce, defined below), minimum latitude of sea ice in the preceding winter, latitude and longitude of sample collection, the days since 1st October that a sample was collected (DaysAfter1Oct), the year of sampling (year, being the year that each spring-summer sampling season began), the time of day that a sample was collected, and macro-nutrient concentrations: phosphate (PO4), silicate (SiO4) and nitrate + nitrite (hereafter nitrate, NOx). Water samples for dissolved macro-nutrients were collected, frozen on ship, and later analysed at CSIRO in Hobart using standard spectrophotometric methods (Hydes et al. 2010). Daily estimates of SAM were obtained from the US NWS Climate Prediction Center's website and are the NOAA Antarctic Oscillation Index values based on 700-hPa geopotential height anomalies (NOAA 2017). The variable DaysSinceSeaIce was defined as the time since sea ice had melted to 20% cover (after Wright et al. 2010) as determined from daily Special Sensor Microwave/Imager (SSM/I) sea ice concentration data distributed by the University of Hamburg (Spreen et al. 2008). To examine the lag in the expression of the SAM on phytoplankton community composition, two response surfaces were constructed relating the variance in phytoplankton community composition explained by the SAM to the temporal positioning of the period over which daily SAM was averaged. These were derived by evaluating separate CAP analyses (described below) based on daily SAM averaged across a range of days {1, 3, 5, … 365} centred on (i) each calendar day individually (1 Jan – 31 Dec) through the year associated with each sample; and (ii) lagged from 1 to 365 days prior to each sample collection date. Empirical identification of the time between variation in the SAM and the manifestation of this variation in the phytoplankton community structure revealed three modes (maxima) in phytoplankton community composition explained by the SAM. The first was an autumn seasonal SAM mode, which was determined to be the average of 57 daily SAM estimates centred on the preceding 11th March (11th Feb – 8th Apr). This mode explained up to 13.3% of the variance in taxonomic composition (SAM autumn). The second was a spring seasonal mode, which was determined to be the average of 75 daily SAM estimates centred on 25th October (20th Sep – 3rd Dec). This mode explained up to 10.3% of variance in taxonomic composition (SAM spring). Unlike the other modes that were related to the time of year, the third mode was timed relative to the date of sample collection for each sample and comprised the average of the 97 daily SAM estimates centred 102 days prior to each sample collection date. It explained 9.9% of the variance in phytoplankton composition (SAM prior). The mean standard error on estimates of SAM were 0.14 SAM index units for SAM autumn and SAM spring, and 0.13 for SAM prior. Note that SAM prior and SAM spring temporally overlapped to varying extents across the 52 samples and so were not entirely independent covariates: for example, a sample collected in the summer had previous days contributing to both SAM prior and SAM spring.

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.

From the abstract and introduction of ANARE Research Notes 44 - ADBEX I cruise to the Prydz Bay region, 1982: nutrient data. Nitrate, phosphate and silicate concentrations obtained during the ADBEX I cruise to the Prydz Bay region in November and December 1982 are plotted with depth and the raw data are tabulated. Location of the sampling stations and the average concentration of each nutrient in the top 100 m of the water column is mapped. The ADBEX I (Antarctic Division BIOMASS Experiment) cruise is part of a long-term, national program of field surveys aimed at fulfilling the objectives of the BIOMASS (Biological Investigation of Marine Antarctic Systems and Stocks) program. The ADBEX I cruise on MV Nella Dan to the Prydz Bay region between 19 November and 17 December 1982, is the second Antarctic Division cruise to contribute to BIOMASS, the first being FIBEX (First International Biomass Experiment) in 1981. Nutrient data were collected at twenty-eight of the seventy-nine hydrographic stations to provide information for the interpretation of phytoplankton distribution and abundance. The sampling locations and depths were not selected, therefore, on the basis of nutrient-related considerations. The concentration of nitrate, phosphate and silicate is plotted to 600 m for each station and where casts were much deeper or much shallower, a second plot is shown. To show water column structure at the time of sampling, sigma-t values were also plotted, unless data for a cast were unavailable. In addition to the depth profiles, the average concentration to 100 m of each nutrient species is mapped to give a first-order approximation of the horizontal pattern of nutrient distribution in the upper layers.

Oceanographic measurements were collected aboard RV Investigator cruise in1801 (CSIRO voyage designation in2018_v01) from 11th January to 22nd February 2018, along CLIVAR Southern Ocean repeat meridional section SR3, followed by Adelie land shelf stations, small meridional sections along 150E (the south end of CLIVAR section P11S) and 132E, and several stations along CLIVAR zonal section S4. A total of 108 CTD vertical profile stations were taken on the cruise, most to within 14 metres of the bottom. Over 2800 Niskin bottle water samples were collected for the measurement of salinity, dissolved oxygen, nutrients (phosphate, nitrate+nitrite, silicate, ammonia and nitrite), CFC's plus tracers (CFC-11, CFC-12, SF6 and N2O), dissolved inorganic carbon (i.e. TCO2), alkalinity, pH, C13/C14, genomics, HPLC, POC, chlorophyll, radiogenic isotopes, helium, ice nucleation, and Ca/Mg, using a 36 bottle rosette sampler. Full depth current profiles were collected by an LADCP attached to the CTD package. Upper water column current profile data were collected by a ship mounted ADCP (75 kHz). Trace metal rosette and in situ pump deployments were done at some of the CTD stations. Meteorological and water property data were collected by the array of ship's underway sensors. A large assortment of 29 drifting floats was deployed throughout the cruise. A detailed data report is included with the data set, with summary of all CTD data and important data quality information. The data set contains CTD 2dbar averaged data, and Niskin bottle data (core hydrochemistry of salinity, dissolved oxygen and nutrients, plus CFC-11, CFC-12, SF6 and N2O), in text and matlab formats. A WOCE (CCHDO) 'exchange' format version of the data is also available from the CCHDO data centre.

Oceanographic measurements were collected aboard Aurora Australis cruise au1602, voyage 2 2016/2017, from 8th December 2016 to 21st January 2017. The cruise commenced with a Casey resupply, followed by work around the Dalton Polynya/Moscow University Iceshelf, then the Mertz Glacier region, and then around the Ninnis Polynya. 14 stations at the southern end of the SR3 transect were also completed. Ice conditions prevented access to the front of the Totten Glacier. A total of 73 CTD vertical profile stations were taken on the cruise, most to within 12 metres of the bottom (Table 1). Over 800 Niskin bottle water samples were collected for the measurement of salinity, dissolved oxygen, nutrients (phosphate, nitrate+nitrite, silicate, ammonia and nitrite), dissolved inorganic carbon (i.e. TCO2), alkalinity, Th-234, POC, Chla, PAM, HPLC, Nd, Po-210/Pb-210, bacteria, O-18, caesium, and Teflon pollutants, using a 24 bottle rosette sampler. Full depth current profiles were collected by an LADCP attached to the CTD package. Upper water column current profile data were collected by a ship mounted ADCP. Meteorological and water property data were collected by the array of ship's underway sensors. 8 Argo floats were also deployed (Table 13) on the transit from Hobart to Casey. The data set contains CTD dbar data and Niskin bottle data (i.e. core hydrochemistry only - salinity, dissolved oxygen and nutrients). A detailed data report is included, with a description of the data and important data quality information.

Oceanographic measurements were collected aboard RV Investigator cruise in1805 (CSIRO voyage designation in2018_v05) from 16th October to 16th November 2018, along a number of transects across a standing meander of the Antarctic Circumpolar Current between 148o and 156oE. A total of 77 CTD vertical profile stations were taken on the cruise, most to within 12 metres of the bottom. Over 1900 Niskin bottle water samples were collected for the measurement of salinity, dissolved oxygen, nutrients (phosphate, nitrate+nitrite, silicate, ammonium and nitrite), chlorophyll, POC and DOC, and for incubation experiments, using a 36 bottle rosette sampler. Full depth current profiles were collected by an LADCP attached to the CTD package. Upper water column current profile data were collected by a ship mounted ADCP (75 kHz and 150 kHz). Data coverage was increased by additional transects towing a Triaxus towed CTD system. A microstructure profiler was deployed at many of the CTD stations. Meteorological and water property data were collected by the array of ship's underway sensors. An oceanographic mooring was deployed at 55o 32.544’S , 150o 52.332’E, and a series of floats and drifters were deployed. Bathymetry was collected by the ship’s multibeam system. The data set contains CTD 2dbar averaged data, and Niskin bottle data (core hydrochemistry of salinity, dissolved oxygen and nutrients), in text and matlab formats, and a full data report. A WOCE (CCHDO) 'exchange' format version of the data is also available on request.

Oceanographic measurements were collected aboard Aurora Australis cruise au1402, voyage 2 2014/2015, from 5th December 2014 to 25th January 2015. The cruise commenced with a Casey resupply, followed by work around the Dalton Polynya/Moscow University Iceshelf/Totten Glacier system, and then around the Mertz Glacier region. A total of 141 CTD vertical profile stations were taken on the cruise, most to within 11 metres of the bottom. Over 1000 Niskin bottle water samples were collected for the measurement of salinity, dissolved oxygen, nutrients (phosphate, nitrate+nitrite and silicate), dissolved inorganic carbon (i.e. TCO2), alkalinity, helium, 18O, and biological parameters, using a 24 bottle rosette sampler. Full depth current profiles were collected by an LADCP attached to the CTD package, and bottom video footage was collected by a camera system (also mounted to the CTD package) for most casts. Upper water column current profile data were collected by a ship mounted ADCP. An underway CTD system (P.I. Alex Orsi, Texas A and M University) was used to collected measurements from the aft of the ship along several small transects around the Dalton Polynya. Meteorological and water property data were collected by the array of ship's underway sensors. 10 'Argo equivalent' floats were also deployed in both the Totten and Mertz regions, for an ice float pilot study. Six oceanographic moorings were recovered from around the Dalton Polynya, three Australian and three US (for the US moorings: P.I.'s Alex Orsi, Texas A and M University, Amy Leventer, Colgate University, and Eugene Domack, University of South Florida). Three temporary acoustic sound source moorings were also deployed then recovered in the same area, in support of an autonomous glider deployment (P.I. Craig Lee, University of Washington). Three oceanographic moorings were recovered from the Mertz region, two Australian and one French (P.I. Marie-Noelle Houssais, Universite Pierre et Marie Curie, for the French mooring). The data set here includes the CTD and Niskin bottle data, in both text and matlab format. The included README file gives full details on file formats.