Locations of sampling sites for ASAC project 40 on voyage 7 of the Aurora Australis in the 2001/2002 season. The dataset also contains information on chlorophyll, carotenoids, coccolithophorids and species identification and counts. The voyage acronym was LOSS. There are 203 observations in the collection. These data are available via the biodiversity database. The taxa represented in this collection are (species names at time of data collection, 2001-2002): Acanthoica quattrospina Calcidiscus leptoporus Coronosphaera mediterranea Emiliania huxleyi Gephyrocapsa oceanica Pentalamina corona Syracosphaera pulchra Tetraparma pelagica Triparma columacea subsp. alata Triparma laevis subsp. ramispina Triparma strigata Umbellosphaera tenuis

The composition, size and abundance of phytoplankton and microzooplankton were measured across a transect from Prydz Bay to Australia during late March 1987. Phytoplankton populations were low, with concentrations of chlorophyll a ranging from 0.08 to 0.22 mg.m-3. Small cells predominated numerically; nanoplankton consistently represented 55 to 68% of the total cell number while picoplankton represented 27 to 44%. Microplankton never represented more than 3% of cells by number, but constituted 57 to 93% of the total cell volume, and accounted for most of the latitudinal variation in total volume. Small flagellates, not identifiable by light microscopy, were the most numerous cells encountered across the transect, with a five-fold increase in abundance at 47S. Numbers of diatoms (most less than 20 microns in size) increased markedly south of the Antarctic Convergence, with a strong correlation to the concentration of silica. Dinoflagellate numbers were relatively constant across the transect, although somewhat higher north of 50S. Those less than 20 microns in size were most numerous and accounted for most of the numerical variation. HPLC analysis of chlorophyll and carotenoid pigments showed a peak of peridinin which coincided with the flagellate peak at 47S, but not with observed dinoflagellates, suggesting that the flagellate peak included unrecognized dinoflagellates. Chlorophyll b and prasinoxanthin were also associated, suggesting a significant contribution by prasinophytes. Almost no cyanobacteria were observed south of the convergence, although very large numbers, which correlated with the abundance of zeaxanthin, were encountered to the north. Numbers of ciliates and tintinnids were quite variable although they followed each other closely. Numbers of both were low in the region of the Antarctic Convergence.

A list of taxa and observations of phytoplankton collected from the SAZ Sense voyage of the Aurora Australis - voyage 3 of the 2006-2007 season. These data are available via the biodiversity database. The collection contains 26 taxa and 562 observations. More information about SAZ SENSE: The overall objective is to characterise Southern Ocean marine ecosystems, their influence on carbon dioxide exchange with the atmosphere and the deep ocean, and their sensitivity to past and future global change including climate warming, ocean stratification, and ocean acidification from anthropogenic CO2 emissions. In particular we plan to take advantage of naturally-occurring, persistent, zonal variations in Southern Ocean primary production and biomass in the Australian Sector to investigate the effects of iron addition from natural sources, and CO2 addition from anthropogenic sources, on Southern Ocean plankton communities of differing initial structure and composition. SAZ-SENSE is a study of the sensitivity of Sub-Antarctic Zone waters to global change. A 32-day oceanographic voyage onboard Australia's ice-breaker Aurora Australis was undertaken in mid-summer (Jan 17 - Feb. 20) 2007 to examine microbial ecosystem structure and biogeochemical processes in SAZ waters west and east of Tasmania, and also in the Polar Frontal Zone south of the SAZ. The voyage brought together research teams from Australasia, Europe, and North America, and was led by the ACE CRC, CSIRO Marine and Atmospheric Research, and the Australian Antarctic Division. The overall goal is to understand the controls on Sub-Antarctic Zone productivity and carbon cycling, and to assess their sensitivity to climate change. The strategy is to compare low productivity waters west of Tasmania (areas with little phytoplankton) with higher productivity waters to the east, with a focus on the role of iron as a limiting micro-nutrient. The study also seeks to examine the effect of rising CO2 levels on phytoplankton - both via regional intercomparisons and incubation experiments.

Processed CTD instrument data - Corrected fluorescence profiles at the Southern Kerguelen Plateau, Indian Sector of the Southern Ocean. The fluorometer was calibrated through the regression of burst measurements against in situ chlorophyll a measured at the same depths and sites using high performance liquid chromatography (Wright et al. 2010). Zero chlorophyll a reference points were included in the regression and were obtained through averaging fluorometry data over 200-300 m bins. The resulting linear equation used to convert flourometry data was: chlorophyll = 0.262*fluorescence + 0.101. Column measurements (µg L-1) and integrated data (0-150 m, mg m-2) for each CTD station are provided.

Gross Primary Production Six depths were sampled per CTD station ranging from near-surface to 125 m. Sample depths were based on downward fluorescence profiles and two of six samples always included both near-surface (approximately 5-10 m) and the depth of the chlorophyll maximum where applicable. Photosynthetic rates were determined using radioactive NaH14CO3. Incubations were conducted according to the method of Westwood et al. (2011). Cells were incubated for 1 hour at 21 light intensities ranging from 0 to 1200 µmol m-2 s-1 (CT Blue filter centred on 435 nm). Carbon uptake rates were corrected for in situ chlorophyll a (chl a) concentrations (µg L-1) measured using high performance liquid chromatography (HPLC, Wright et al. 2010), and for total dissolved inorganic carbon availability, analysed according to Dickson et al. (2007). Photosynthesis-irradiance (P-I) relationships were then plotted in R and the equation of Platt et al. (1980) used to fit curves to data using robust least squares non-linear regression. Photosynthetic parameters determined included light-saturated photosynthetic rate [Pmax, mg C (mg chl a)-1 h-1], initial slope of the light-limited section of the P-I curve [α, mg C (mg chl a)-1 h-1 (µmol m-2 s-1)-1], light intensity at which carbon-uptake became maximal (calculated as Pmax/ α = Ek, µmol m-2 s-1), intercept of the P-I curve with the carbon uptake axis [c, mg C (mg chl a)-1 h-1] , and the rate of photoinhibition where applicable [β, mg C (mg chl a)-1 h-1 (µmol m-2 s-1)-1]. Gross primary production rates were modelled using R. Depth interval profiles (1 m) of chl a from the surface to 200 m were constructed through the conversion of up-cast fluorometry data measured at each CTD station. For conversions, pooled fluorometry burst data from all sites and depths was linearly regressed against in situ chl a determined using HPLC. Gross daily depth-integrated water-column production was then calculated using chl a depth profiles, photosynthetic parameters (Pmax, α , β, see above), incoming climatological PAR, vertical light attenuation (Kd), and mixed layer depth. Climatological PAR was based on spatially averaged (49 pixels, approx. 2 degrees) 8 day composite Aqua MODIS data (level 3, 2004-2017) obtained for Julian day 34. Summed incoming light intensities throughout the day equated to mean total PAR provided by Aqua MODIS. Kd for each station was calculated through robust linear regression of natural logarithm-transformed PAR data with depth. In cases where CTD stations were conducted at night, Kd was calculated from a linear relationship established between pooled chlorophyll a concentrations and Kd’s determined at CTD stations conducted during the day (Kd = -0.0421 chl a * -0.0476). Mixed layer depths were calculated as the depth where density (sigma) changed by 0.05 from a 10 m reference point. Gross primary production was calculated at 0.1 time steps throughout the day (10 points per hour) and summed.

This dataset is derived from sediment trap records collected by Thomas Trull as part of the multidisciplinary SAZ Project initiated in 1997 by the Antarctic Cooperative Research Centre (ACE CRC) (Trull et al 2001b). The current submission provides data not included in Wilks et al. (submitted) 'Biogeochemical flux and phytoplankton assemblage variability: A unique year-long sediment trap record in the Australian Sector of the Subantarctic Zone.' This dataset contains three parts: Supplementary Table 1 describes sediment trap deployment information and current speed measured during deployment. Supplementary tables 2a and 2b are raw diatom counts of every species encountered at the site, at every sampling cup. Table 2a contains the 500 m trap depth record, while table 2b is for the 2000 m trap depth record. Supplementary table 3 contains environmental data (chlorophyll-a, photosynthetically active radiation, and sea surface temperature) for each cup record.

These data relate to a large-scale early-autumn phytoplankton bloom that occurred off Cape Darnley, East Antarctica, in March 2012. The bloom was detected by Dr Jan Lieser (Antarctic Climate and Ecosystems Cooperative Research Centre, ACE-CRC) through MODIS satellite and was opportunistically sampled from RSV Aurora Australis using the uncontaminated seawater line. Samples were analysed for protist species and abundances using light and scanning electron microscopy, and pigment analyses were conducted using high performance liquid chromatography. Additional water samples were taken for dissolved nutrient analyses. Specific details of the files are: Cape Darnley Protist Counts Samples were preserved with 1 % vol:vol Lugols iodine and stored in glass bottles in the dark at 4 degrees C. Protists were identified and counted using phase and Nomarski interference optics using Olympus IX71 and IX81 inverted microscopes at 400X to 640X magnification. Bright field optics were also used to discriminate taxa that contained chloroplasts. Protistan taxa were counted in 20 randomly chosen fields of view, except for highly abundant taxa that were counted in a subset of the field of view defined by an ocular quadrant (Whipple grid). Cell biovolumes and carbon conversion statistics were used to calculate the cell biomass of protistan taxa/groups. Cape Darnley Fluorometer Calibration Fluorometer measurements from the ships underway system were calibrated using chlorophyll a readings determined through high performance liquid chromatography. A linear relationship was established between fluorometer v HPLC chlorophyll a measurements at the same sites. The linear equation was then used to convert all underway fluorometry data from the voyage. Cape Darnley Bloom HPLC Pigments CHEMTAX summary Major phytoplankton groups at each site determined through analysis of pigments using high performance liquid chromatography and CHEMTAX. Methods were according to that of Wright et al. (2010). Cape Darnley Bloom Nutrients Dissolved nutrient concentrations. Samples were analysed by the Department of Primary Industries, Parks, Water and Environment, 18 St. Johns Avenue, Newtown, Tasmania 7008. Cape Darnley Underway Data VOYAGE_04_0_201112 Raw underway data from Aurora Australis in the bloom region Cape Darnley Underway Data Maps Maps of the underway data in the bloom region

Locations of sampling sites for ASAC project 40/1343 on voyage 3 of the Aurora Australis in the 2001/2002 season. The dataset also contains information on chlorophyll, carotenoids, coccolithophorids and species indentification and counts. The data can be accessed via the Biodiversity Database at the provided URL. From the abstract of the referenced publication: Variations of phytoplankton assemblages were studied in November-December 2001, in surface waters of the Southern Ocean along a transect between the Sub-Antarctic Zone (SAZ) and the Seasonal Ice Zone (SIZ; 46.9-64.9 degrees S; 142-143 degrees E; CLIVAR-SR3 cruise). Two regions had characteristic but different phytoplankton assemblages. Nanoflagellates (less than 20 microns) and pico-plankton (~2 microns) occurred in similar concentrations along the transect, but were dominant in the SAZ, Sub-Antarctic Front (SAF), Polar Front Zone (PFZ) and the Inter-Polar Front Zone (IPFZ), (46.9-56.9 degrees S). Along the entire transect their average cell numbers in the upper 70 m of water column, varied from 300,000 to 1,100,000 cells per litre. Larger cells (greater than 20 microns), diatoms and dinoflagellates, were more abundant in the Antarctic Zone-South (AZ-S) and the SIZ (60.9-64.9 degrees S). In AZ-S and SIZ diatoms ranged between 270,000 and 1,200,000 cells per litre, dinoflagellates from 31,000 to 102,000 cells per litre. A diatom bloom was in progress in the AZ-S showing a peak of 1,800,000 cells per litre. Diatoms were dominated by Pseudo-nitzschia spp., Fragilariopsis spp., and Chaetoceros spp. Pseudo-nitzschia spp. outnumbered other diatoms in the AZ-S. Fragilariopsis spp. were most numerous in the SIZ. Dinoflagellates contained autotrophs (eg Prorocentrum) and heterotrophs (Gyrodinium/Gymnodinium, Protoperidinium). Diatoms and dinoflagellates contributed most to the cellular carbon: 11-25 and 17-124 micrograms of carbon per litre, respectively. Small cells dominated in the northern region characterised by the lowest N-uptake and new production of the transect. Larger diatom cells were prevalent in the southern area with higher values of N-uptake and new production. Diatom and nanoflagellate cellular carbon contents were highly correlated with one another, with primary production, and productivity related parameters. They contributed up to 75% to the total autotrophic C biomass. Diatom carbon content was significantly correlated to nitrate uptake and particle export, but not to ammonium uptake, while flagellate carbon was well correlated to ammonium uptake, but not to export. Diatoms have contributed highly to particle export along the latitudinal transect, while flagellates played a minor role in the export. This work was completed as part of ASAC projects 40 and 1343. See also the related metadata record, "Spring Phytoplankton Assemblages in the Southern Ocean Between Australia and Antarctica".

Overview of the project and objectives: Sea-ice phytoplankton is significantly enriched in 13C (delta 13C-POC) compared to pelagic phytoplankton in adjacent open waters because of carbon limitation in the brine pockets and due to physiological properties such as the presence of Carbon Concentrating Mechanisms (CCM) and/or the uptake of bicarbonate (HCO3-). Melting of sea-ice with release of sea-ice phytoplankton occurs during the growth season, so these isotopically heavy particles, if sinking out of the surface waters, can be expected to be found deeper in the water column. One hypothesis is that the natural carbon isotopic signal of brassicasterol (phytosterol, mainly diatom indicator) in the south Antarctic Bottom Water (AABW), a water mass which is influenced by the Seasonal Ice Zone (SIZ), is enriched compared to northern deep waters signal due to an enhanced contribution of sea-ice diatoms. The objective of this dataset acquisition is to gain information on the delta 13C signal of brassicasterol in sea-ice diatoms and further estimate the contribution of sea-ice algae release in the Southern Ocean biological pump. In the course of the expedition, a second choice has been done to look at the presence of particulate barium in the sea-ice. In the open ocean, presence of particulate barium in the mesopelagic layer is an indicator of remineralisation process. The main idea is that marine snow composed of detritical organic matter (aggregates, faecal pellets, etc.) provides micro-environment favorable for precipitation of excess Barium or Baxs (total particulate Ba minus the lithogenic part; mainly constituted of barite crystals, BaSO4): is there such Baxs components in the sea-ice? Methodology and sampling strategy: Sampling strategy follows ice stations deployment via Bio ice-core type. Most of the time we worked close to / directly on the Trace Metal site following precautions concerning TM sampling (clean suits etc.). When we worked close to the TM site, precautions were not such important because we don't need the same drastic precautions for our own sampling. We work together because we want to propose a set of data which helps to characterize the system of functioning in close relation with TM availability (for that, sampling location have to be as close as possible). Ice melted from ice-core sections (see attached files for more details) is filtered on precombusted GF-F filters (0.7 microns porosity) and filters are stored at -20 degrees C. For particulate Barium sampling, same protocol but filtration on PC filters 0.4 microns, dry over night and store at ambient temperature. At home laboratory (VUB, Brussels, Belgium), sterols samples are analysed via Gas Chromatography - Mass Spectrometer (GC-MS) and Gas Chromatography-combustion column-Isotope Ratio Mass Spectrometer (GC-c-IRMS) after chemical treatment. Barium sample are analysed via Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES).

The data reports the pigment concentrations and results of CHEMTAX analysis for 2 summer seasons in Antarctic. In 2008/09 three experiments in which 6 x 650 l minicosms (polythene tanks) were used to incubate natural microbial communities (less than 200 um diameter) at a range of CO2 concentrations while maintained at constant light, temperature and mixing. The communities were pumped from ice-free water ~60 m offshore on 30/12/08, 20/01/09 and 09/02/09. These experiments received no acclimation to CO2 treatment. A further experiment was performed in 2014/15 using water helicoptered from ~ 1 km offshore amongst decomposing fast ice on 19/11/14. This experiment included a 5 day period during which the community was exposed top low light and the CO2 was gradually raised to the target value for each tank, followed by a two day period when the light was raised to an irradiance that was saturating but not inhibitory for photosynthesis. A range of coincident measurements were performed to quantify the structure and function of the microbial community (see Davidson et al. 2016 Mar Ecol Prog Ser 552: 93–113, doi: 10.3354/meps11742 and Thomson et al 2016 Mar Ecol Prog Ser 554: 51–69, 2016, doi: 10.3354/meps11803). The data provides a matrix of samples against component pigment concentration and the output from CHEMTAX that best explained the phytoplankton composition of the community based on the ratios of the component pigments. For the 2008/09 experiments, samples were obtained every 2 days for 10, 12 and 10 days in experiments 1, 2 and 3 respectively. In 2014/15 samples were obtained from each incubation tank on days 1,3, 5, and 8 during th acclimation period and every 2 days until day 18 thereafter. For each sample a measured volume was filtered through 13 mm Whatman GF/F filters for 20 mins. Filters were folded in half, blotted dry, and immediately frozen in liquid nitrogen for analysis in Australia. Pigments were extracted, analysed by HPLC, and quantified following the methods of Wright et al. (2010). Pigments (including Chl a) were extracted from filters with 300 micro l dimethylformamide plus 50 micro l methanol, containing 140 ng apo-8'-carotenal (Fluka) internal standard, followed by bead beating and centrifugation to separate the extract from particulate matter. Extracts (125 micro l) were diluted to 80% with water and analysed on a Waters HPLC using a Waters Symmetry C8 column and a Waters 996 photodiode array detector. Pigments were identified by comparing retention times and spectra to a mixed standard sample from known cultures (Jeffrey and Wright, 1997), run daily before samples. Peak integrations were performed using Waters Empower software, checked manually for corrections, and quantified using the internal standard method (Mantoura and Repeta, 1997).