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

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.

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.

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.

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.

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).

Metadata record for data from ASAC Project 2307 See the link below for public details on this project. ---- Public Summary from Project ---- The project investigates microbial life in the Southern Ocean. The studies will investigate two areas - the role of bacteria in the regeneration of the important nutrient silica via decomposition of planktonic biomass and to assess the importance of prokaryotic polyunsaturated fatty acid (PUFA) entering the marine food web from natural communities in Antarctic sea ice and the Southern Ocean. Project objectives: 1. Investigate the role of bacteria in the colonisation and decomposition of phytoplankton and concomitant redispersal of silica from phytoplankton in seawater of the Southern Ocean at various different latitudes. 2. Validate real-time PCR (5-prime nuclease PCR assay) for rapid quantification of key bacterial found in seawater to determine their association with phytoplankton decomposition and silica redispersal. Significance: Recent studies (Bidle and Azam, 1999) demonstrate that much silica regeneration in seawater is due to bacterial enzymatic activity and that diatom decomposition and silica release is highly accelerated in the presence of an active colonising bacterial population. The formation of bacterial biofilms and production of extracellular enzymes on phytoplanktic detritus and aggregates appears to lead to the direct breakdown of proteins and polysaccharides which hold together the diatom frustules. In the Southern Ocean this process could be significant as the foodweb there is sustained by phytoplanktonic (mostly diatom) primary productivity (Bunt 1963) whether it be in sea-ice or in the pelagic zone. If silica redispersal does not occur diatoms would instead eventually become buried in sediment with silica supplies becoming limited, except that supplied by aeolian and terrigenous input. In the marine environment half of primary-produced organic matter is degraded by bacteria (Cole et al., 1988). Thus the bacterial decomposition of diatom biomass and subsequent release of dissolved silica should be an important and relatively rapid process in Southern Ocean waters. At this stage there is still limited data on the role of bacteria in regeneration of silica in the overall marine environment. The study of Bidle and Azam (1999) examined seawater off of California and mostly examined the process itself. Currently, the role of specific bacteria is being examined by Kay Bidle (personal communication) and John Bowman is supplying various marine bacteria to assess this. In the proposed study we wish to examine the role of bacteria in the Southern Ocean in the decomposition of diatom biomass, rate of release of dissolved silica and bacterial groups involved in the process. This research should reveal some fundamental knowledge on a integral role of bacteria in Southern Ocean ecosystems. In order to assess the bacterial role in silica redispersal we wish to use three molecular ecological techniques: fluorescent in situ hybridisation (FISH), denaturing gradient gel electrophoresis (DGGE) and real-time PCR. FISH and DGGE analysis are well established in John Bowmans laboratory and are being used routinely for analysis of Antarctic and Tasmanian natural samples (seawater and sediment). The real-time PCR analysis which can be used as a sensitive quantitative assay for bacterial populations in natural samples is currently in development using a recently purchased Rotorgene (Corbett Research) instrument. The method has been used to great effect in measuring rapidly bacterial populations in seawater (eg., Suzuki et al. 2000). Using these methods will allow us to accurately measure changes in bacterial populations during colonisation and decomposition of the diatom biomass during the silica redispersal experiments. There are two data files associated with this project. Part 1: Total of 9 files: File 1. Seawater sample data - information from two cruises in 2000 and 2001 - includes position of sample, types of sample, temperature and analyses performed subsequently. File 2. 16S rRNA gene sequences derived from Southern ocean seawater bacterial isolates. Sequences are all deposited in the GenBank nucleotide database and are in FASTA format. File 3. 16S rRNA gene sequences derived from denaturing gradient gel electrophoretic gel slices via extraction, PCR and cloning. Sequences are all deposited in the GenBank nucleotide database and are in FASTA format. File 4. Flavobacteria abundance in Southern Ocean samples on the basis of depth. Abundance determined using fluorescent insitu hybridisation using universal bacterial probe EUB338 and flavobacteria specific probe. Details of sites analysed are included in the seawater sample file. File 5. Flavobacteria abundance in Southern Ocean samples on the basis of latitude (transect from 47 S to 63 S). Abundance determined using fluorescent insitu hybridisation using universal bacterial probe EUB338, alphaproteobacteria, gammaproteobacteria and flavobacteria specific probe. Total count of bacteria was determined by epifluorescence using DAPI. Details of sites analysed are included in the seawater sample file. File 6. Nutrient and chlorophyll a data for samples studied (see seawater sample file) including nitrate, phosphate and silica. File 7. Bacterial isolate information including strain designations, site location, and identification to genus level. File 8. . Bacterial isolate fatty acid data for strains designated as novel in bacterial isolate information file. Fatty acids determined using GC-MS analytical methods. File 9. Bacterial isolate phenotypic data for strains designated as novel in bacterial isolate information file. Includes morphological, physicochemical, biochemical and nutritional profile data. Part 2: Total of 4 files: File 1. 16S rRNA gene sequences derived from denaturing gradient gel electrophoretic (DGGE) gel slices via extraction, PCR and cloning. DGGE analysis performed on samples analysed over 30 days from 20 litre microcosms derived from southern seawater to which was added 10 mg sterile diatom detritus derived from axenic Nitszchia closterium. Sequences are all deposited in the GenBank nucleotide database and are in FASTA format. File 2. Flavobacteria abundance in Southern Ocean seawater microcosms over 30 days. Abundance determined using real-time PCR using universal bacterial and flavobacteria specific PCR primers. File 3. Bacterial mediated silica release data from Southern Ocean seawater microcosms over 30 days. Includes non-detritus amended controls that indicate the natural level of of seawater silica. Silica analysis performed by a chemical procedure. File. 4. Seawater sample data obtained during 2001 indicating the sites for seawater used for creating 20 l microcosms and used to assess silica release by bacteria from diatom detritus.

Antarctic sea ice is known to store key micronutrients, such as iron, as well as a suite of less studied trace metals in winter which are rapidly released in spring. This stimulates ice edge phytoplankton blooms which drive the biological removal of climatically-important gases like carbon dioxide. By linking the distribution of iron and other trace elements to the cycles of carbon, nitrogen and silicon in the sea ice zone in spring, this project will identify their biogeochemical roles in the seasonal ice zone and how this may change with predicted climate-driven perturbations. 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 is analysed for temperature, salinity, nutrients, unfiltered and filtered metals. Snow thickness is recorded with a ruler. Ice cores were collected using a noncontaminating, 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 is 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). All those data, read from the screens instruments are directly inserted in the spreadsheet 'Notebook SIPEX-2' in the '4051 Lannuzel' folder. 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 are taken 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 are directly triple bagged in plastic bags (the inner one is milli-Q washed) and frozen at -20 degrees 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. Those samples are used to analyse unfiltered and filtered metals, Chla, POC/PON, nutrients and DOC. Filtration for filtered metals is done on board using a peristaltic pump and a 0.2 micron cartridge filter. All the unfiltered and filtered metals collected are acidified (2 ppt HCl seastar) and stored at room temperature until analysis at the laboratory. Nutrients, DOC and filters for POC/PON are frozen at -20 degrees C until analysis. Chla filtrations and analysis are done on board. Auxiliary cores/brines/underlying seawater were also collected for Caitlin Gionfriddo (caitlingio@gmail.com, Uni. Melbourne) for total mercury (Hg) and methyl-Hg. Also included in this dataset are typed field notes.