This metadata record contains the results from 3 bioassays conducted with the Antarctic marine microalgae Cryothecomonas armigera (incertae sedis). These tests assessed the toxicity of copper, cadmium, lead, zinc and nickel. Test conditions for both algae are described in the excel spreadsheets. In summary, tests for P. antarctica and C.armigera, were carried out at 0 plus or minus 2 degrees C, 20:4 h light:dark (60-90 micromol/m2/s, cool white 36W/840 globes), in 80 mL natural filtered (0.22 microns) seawater (salinity - 35 ppt, pH - 8.1 plus or minus 0.2). Filtered seawater was supplemented with 1.5 mg/L NO3- and 0.15 mg/L of PO43-. All tests were carried out in silanised 250-mL glass flasks, with glass lids. Tests 1 and 2 consisted of metal treatments, with 3 replicates per treatment, alongside 3 replicate controls (natural filtered seawater). Test 3 consisted of metal treatments in an increasing series (no replicates) alongside 3 replicate controls. Seawater was spiked with metal solutions to achieve required concentration. Concentrations tested are recorded in excel datasheets as dissolved metal concentrations measured on day 0, and day 24. The average of the dissolved metal concentrations were used for further statistical analysis. The age of C.armigera at test commencement was 25-30 days. Algal cells were centrifuged and washed to remove nutrient rich media, and test flasks were inoculated with between 1-3 x10^3 cells/mL. Cell densities in all toxicity tests were determined by flow cytometry. Toxicity tests with C. armigera were carried out over 23-24 days, with cell densities determined twice a week. The growth rate (cell division; u) was calculated as the slope of the regression line from a plot of log10 (cell density) versus time (h). Growth rates for all treatments were expressed as a percentage of the control growth rates. The flow cytometer was also used to simultaneously measure changes in the following cellular parameters: chlorophyll a autofluorescence intensity (FL3), cell size (FSC) and cell complexity (SSC). The molecular stain BODIPY 493/503, was used to measure neutral lipid concentrations. Changes in cellular parameters were measured by applying a gate that captured greater than 95% of control cells in a region, R2. Changes in cellular parameters were observed in metal treatments as a shift of the cell population from the R2 region to R1 (for relative decreases) or to R3 (for relative increases). The proportion of cells in each region is expressed as a percentage of the total cell population. The pH was measured on the first and last day of the test. Sub-samples (5 mL) for analysis of dissolved metal concentrations were taken from each treatment on 24. Sub-samples were filtered through an acid washed (10% HNO3, Merck) 0.45-microns membrane filter and syringe, and acidified to 0.2% with Tracepur nitric acid (Merck). Metal concentrations were determined using inductively coupled plasma-atomic emission spectrometry (ICP-AES; Varian 730-ES) for Cu, Cd, Pb, Ni and Zn. Detection limits for Cu, Cd, Pb, Ni and Zn were 1.0, 0.3, 3.2, 1.4, and 1.0 micrograms per litre, respectively. Calculations of effect concentrations (EC 10 and 50) were made using the 'Dose Response Curve' package of R statistical analysis software. Concentration-response curves had several models applied to them, and were tested for best fit by comparing residual standard errors and Akaike's 'An Information Criterion' function . Generally, log-logistic models with 3 parameters provided the best fit. Data for each toxicity test is combined in a single excel spreadsheet, "Cryothecomonas armigera single metal toxicity". The first worksheet is titled "Test Conditions" which provides information on the toxicity test, e.g. species and metals tested, dates, test conditions, as well as explanation of abbreviations, definitions of toxicity values etc. The second worksheet includes the raw cell densities determined in each flask, the calculated growth rates, and measured metal concentrations. The third worksheet contains the measured physiological parameters: Neutral lipid concentrations (BODIPY 493/503), chlorophyll a autofluorescence (FL3), cell complexity (SSC), and cell size (FSC). The final worksheet contains the output of statistical analysis; dose-response curves for each metal with applied log-logistic model and 95% confidence interval, a table summarising the effect concentrations (EC10 and EC50), and No Effect Concentration (NEC) is also provided. The file "C. armigera combined.csv" contains rows representing individual exposures with columns for the metal treatment (Metal), averaged dissolved metal concentration for each exposure (Conc), growth rate (Growth), and growth rate as a percent of the control (Pcon). This data was used for data analysis in R statistics. Note that this contains data from all bioassays conducted with C. armigera, including those conducted by Francesca Gissi (doi:10.4225/15/551B2B65A73F3) The script used for data analysis is provided in the document "R statistics script for C. armigera single metal.docx"

Sea-ice cores (0.09 m internal diameter) were sampled during Polarstern voyage PS117 to the Weddell Sea during December 2018 to January 2019. Ice core measurements include position, snow thickness, ice thickness, ice core temperature and bulk-salinity profiles, macro-nutrient concentrations as well as Chlorophyll-a pigment content. In addition on each ice station downwelling (surface) and under-ice irradiances were measured with a hyperspectral radiometer.

Pulse Amplitude Modulation (WaterPAM, Walz) was used to measure the response of the sea ice brine microalgae to CO2 stress. All data was reported in WinControl software and follows standard formats. Three incubation experiments were carried out at SIPEX stations 4 (expt 1) 7 (expt 3) and 8 (expt 4). File nomenclature TO: time zero TR1,2,3 refers to times 2,3 and 4 respectively In expt 4 the coding refers to hours since beginning of experiment Each file contains data in the same columns: Important results include Column E: F Column F: Fm Column G: Fv/Fm Column H: rETR Column I: PAR

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, during which the porosity of sea ice increased but thickness remained constant. Ice cores destined for spectral transmission profiles were to be collected whole and intact, but due to the presence of fractures in the sea ice, drilling (manual as well as motor powered) resulted in fractured core samples. The protocol was therefore modified: cores were sectioned in 20 cm sections and spectral transmission measured for each section. Spectral transmission profiles across the entire thickness of sea ice are to be re-constructed from the discrete data points. The accuracy of the approach will be assessed against the in situ spectral transmission data. The download file contains three spreadsheets (two of them are csv files), and a readme document which provides detailed information about the three spreadsheets.

Fast repetition rate fluorometer (FRRF) study of sea ice algae in low iron conditions. Algae were grown in an ice tank and the measurements were made at the end with a Chelsea Insrtuments FRRF. Materials and Methods (see the download document for original formatting and formulas) 1. Ice tank incubation The polar pennate diatom Fragilariopsis cylindrus, isolated from Antarctic pack ice in 2015 (Davis station, East Antarctica) was incubated in a purpose designed ice tank (Island Research, Tasmania). The ice tank, which was contructed of titanium to minimise dissolved Fe, was placed into a freezer (–20 degrees C), and the ice thickness and temperature gradient controlled by interaction between a basal heater and the adjustable ambient freezer temperature (see Kennedy et al., 2012). This enabled an ice thickness of approximately 5.5 cm to be maintained during the experiment. The diatom F. cylindrus was incubated in Aquil media (Price et al. 1989) buffered with ethylenediaminetetraacetic acid (EDTA) at 150 micro mol photons m−2 s−1 (PAR), a salinity of 35, and a Fe concentration of 400 nM, where the concentration of total inorganic forms of Fe (Fe') was 1.54 nM, this being continuously supplied to the medium and the exact value calculated using the software Visual MINTEQ, ver. 3.1 (https://vminteq.lwr.kth.se). Before a freezing cycle started, the seawater temperature was maintained at 2.5 degrees C, and a sample was obtained to assess the original physiological state of the algae (Day−5, hereafter). After obtaining the sample, the seawater temperature was set to −1.8 degrees C to initiate ice formation in the ice tank. Once ice had formed at Day−2, the under-ice seawater was partially replaced with ultrapure water to reduce the salinity down to 35, because the salinity had increased (to approximately 38) as a result of brine rejection from the ice. After a 2-day acclimation to the new salinity, ice samples were obtained every 5 days for 20 days (i.e., Days 0, 5, 10, 15, and 20). To minimize the heterogeneity among ice cores, ice samples were randomly collected from the tank chamber with a trace metal-free hand drill (2 cm in diameter) from randomly annotated grids on the ice surface, following normal random sampling numbers generated by the software R (https://www.r-project.org/). To assess the effects of melting and high light exposure, the ice was melted at 2.5 degrees C for 2 days. After the ice had completely melted, the seawater was exposed to a high light level, which was adjusted to represent the likely summer light intensity at the surface in ice-edge regions (800 micro mol photons m−2 s−1; MODIS Aqua), Seawater samples were obtained both after the melting and light exposure events (Melt and Light, respectively, hereafter). 2. Fast repetition rate (FRR) fluorometry To monitor the photophysiology of F. cylindrus during the freezing and melting processes, variable chlorophyll a fluorescence (ChlF) measurements were conducted using a bench-top Fast Repetition Rate fluorometer (FRRf) (FastOcean Act2Run Systems, Chelsea Technologies) with Act2Run software (Chelsea Technologies). Ice samples were directly thawed at 2 degrees C in the dark for 30 min, and the slushily melted ice samples were placed in a quartz tube and their flouresence (ChlF) was measured. A single turnover protocol was applied for the ChlF measurements; 100 flashlets with 1 micro second duration at a wavelength 450 nm and 2 micro second intervals for excitation of reaction centres of photosystem II (PSII, hereafter), and 20 flahlets with 1 μs duration and 100 micro second intervals for relaxation. Eighteen light steps were applied to generate a rapid light curve (RLC) from 0 to 1800 μmol photons m−2 s−1, taking less than 5 min to complete one RLC. At each light step (~15 s), at least five induction and relaxation curves were averaged to obtain ChlF yields, described in Table, after calibrating the ChlF yields with filtered seawater. According to the models proposed by Kolber et al. (1998), photosynthetic parameters of chlorophyll a (chl a) induction and relaxation curves were calculated based on the ChlF yields as shown in Table. Electron transport rate though the reaction centres of PSII (RCII) (ETRRCII) was calculated as per the equation detailed in the download document.

This dataset contains pulse amplitude modulated (PAM) fluorometry measurements and chlorophyll concentrations for a series of incubation experiments performed during the 2012 SIPEX marine science voyage. The PAM files are in a raw format, but can be opened using Microsoft Excel. Light curves have not been processed. Bloom potential: 4-8 ice cores were collected from 4 fast ice stations during SIPEXII (Stations 20120926, 20121006, 20121013, 20121019) and ice collected from the back of the ship (Underway ice collection). The bottom 3cm was shaved off each ice core into filtered seawater. The concentration of chlorophyll a in the slurry was measured using a Turner 10AU fluorometer and the physiological health was determined using a PAM fluorometer. 5 x 50ml cultures from each ice station were incubated for 15-30 days (~50uE, ~0.2 degrees). At the end of the incubation period, the physiological health of the cultures was measured again, as was chlorophyll a. Post-incubation samples were also collected to determine nutrient concentration and species composition. C02: Brine algae was collected from sack holes drilled to a depth of ~45cm from 3 fast ice stations during SIPEXII (Stations 20121006, 20121013, 20121019). PAM fluorometry was used to measure cell health prior to the brine solution being aliquoted into 50ml culture vials to produce 4 treatments: 0.1% CO2, 1% CO2, 2% CO2, control. Cultures were incubated for 7-12 days. Post incubation analyses included: PAM, chlorophyll a, DIC, TA and cell identification. Samples were also collected for DNA extraction, which was performed at sea. The files in this dataset are: 1. McMinn Bloom Dynamics folder. This folder contains raw PAM data from each of the experiments. This is highly specialised photophysiology data, please consult the Walz PAM manual (www.walz.com) for interpretation. The dates and duration of each incubation experiment can be determined from the raw data. 2. McMinn CO2 folder. This contains raw PAM data, dates and experiment duration.

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 papers: In March 1998 we measured iron in the upper water column and conducted iron- and nutrient-enrichment bottle-incubation experiments in the open-ocean Subantarctic region southwest of Tasmania, Australia. In the Subtropical Convergence Zone (~42 degrees S, 142 degrees E), silicic acid concentrations were low (less than 1.5 micro-M) in the upper water column, whereas pronounced vertical gradients in dissolved iron concentration (0.12-0.84 nM) were observed, presumably reflecting the interleaving of Subtropical and Subantarctic waters, and mineral aerosol input. Results of a bottle-incubation experiment performed at this location indicate that phytoplankton growth rates were limited by iron deficiency within the iron-poor layer of the euphotic zone. In the Subantarctic water mass (-46.8 degrees S, 142 degrees E), low concentrations of dissolved iron (0.05-0.11 nM) and silicic acid (less than 1 micro-M) were measured throughout the upper water column, and our experimental results indicate that algal growth was limited by iron deficiency. These observations suggest that availability of dissolved iron is a primary factor limiting phytoplankton growth over much of the Subantarctic Southern Ocean in the late summer and autumn. The importance of resource limitation in controlling bacterial growth in the high-nutrient, low-chlorophyll (HNLC) region of the Southern Ocean was experimentally determined during February and March 1998. Organic- and inorganic-nutrient enrichment experiments were performed between 42 degrees S and 55 degrees S along 141 degrees E. Bacterial abundance, mean cell volume, and [3H]thymidine and [3H]leucine incorporation were measured during 4- to 5-day incubations. Bacterial biomass, production, and rates of growth all responded to organic enrichments in three of the four experiments. These results indicate that bacterial growth was constrained primarily by the availability of dissolved organic matter. Bacterial growth in the subtropical front, subantarctic zone, and subantarctic front responded most favourably to additions of dissolved free amino acids or glucose plus ammonium. Bacterial growth in these regions may be limited by input of both organic matter and reduced nitrogen. Unlike similar experimental results in other HNLC regions (subarctic and equatorial Pacific), growth stimulation of bacteria in the Southern Ocean resulted in significant biomass accumulation, apparently by stimulating bacterial growth in excess of removal processes. Bacterial growth was relatively unchanged by additions of iron alone; however, additions of glucose plus iron resulted in substantial increases in rates of bacterial growth and biomass accumulation. These results imply that bacterial growth efficiency and nitrogen utilisation may be partly constrained by iron availability in the HNLC Southern Ocean. The download file also contains three excel spreadsheets of iron data from the project. The file Sedwick_A9706_Fe_data contains water-column dissolved Fe and total-dissolvable Fe data from cruise A9706, which is presented in Sedwick et al. (1999) and Sedwick et al. (2008). The files Sedwick_A9706_ProcessStn1_Exp_data and Sedwick_A9706_ProcessStn2_Exp_data present data from shipboard experiments conducted during cruise A9706 at Process Stations 1 and 2, respectively, as reported in Sedwick et al. (1999).

Data were collected during deployments of an instrumented Remotely Operated Vehicle on 5 sampling days to determine sea ice physical properties and measure transmitted under-ice radiance spectra (combined with surface irradiance measurements) to estimate the spatial distribution and temporal development of ice algal biomass in land-fast sea ice. The ROV was instrumented with a navigation/positioning system (linked to surface GPS), upward-looking sonar and accurate depth sensor (Valeport 500 (to determine sea-ice draft)), and a upward-looking TriOS Ramses radiance sensor as well as several video-cameras collecting under-ice footage. Parallel measurements included surface irradiance measurements. A readme file in the download explains the folder structure of the dataset.

This metadata record contains observed and predicted toxicity data from bioassays with two species of Antarctic marine microalgae: Phaeocystis antarctica (Prymnesiophyceae) and Cryothecomonas armigera (Cercoza). Bioassay exposures were of mixtures of 5 metals at two ratios, an Environmental (ENV) and Equitoxic (EC) mixture. The measured dissolved metal concentrations were used in two mixture reference models, Independent Action (IA) and Concentration Addition (CA), to predict toxicity as population growth rate inhibition. A Flow Cytometer (BD-FACSVerse) was used to measure the density of microalgae over time, which was then converted to a growth rate. An inductively coupled plasma-atomic emission spectrometry (ICP-AES; Varian 730-ES), was used to measure metal concentrations. Data for each microalga is provided in individual excel spreadsheets, identified by the species tested. A word document is provided that contains the R code used to predict toxicity to the two microalgae by the reference models Independent Action and Concentration Addition. The R code also includes the steps required to extend the models to include a deviation parameter “a” that allows for departure from model additivity. A nested F-test then tests for significance between the fit of each test to observed toxicities. This R code has been adapted to use EC10 as parameter estimates, rather than EC50s. The code was adapted from the approach outlined in Hochmuth, J. D.; Asselman, J.; De, S. Are Interactive Effects of Harmful Algal Blooms and Copper Pollution a Concern for Water Quality Management? Water Res. 2014, 60, 41–53. DOI: 10.1016/j.watres.2014.03.041. Single-metal toxicity data and experimental protocols for P. antarctica from the following paper: and C. armigera used in this study can be found in the following papers: A robust bioassay to assess the toxicity of metals to the Antarctic marine microalga Phaeocyctis antarctica. Francesca Gissi, Merrin S. Adams, Catherine K. King, Dianne F. Jolley (2015). Environmental Toxicology and Chemistry. 2015 Feb 20. doi: 10.1002/etc.2949. Chronic toxicity of five metals to the polar marine microalga Cryothecomonas armigera – Application of a new bioassay. Darren J. Koppel, Francesca Gissi, Merrin S. Adams, Catherine K. King, and Dianne F. Jolley, (2017). Environmental Pollution, Volume 228, 2017, Pages 211-221, doi.org/10.1016/j.envpol.2017.05.034.

Chlorophyll data was used to measure growth rates of sea ice algae in CO2 incubations. Sea ice brine microalgae was collected from sackholes. Replicate samples were incubated in ambient air (~0.04% CO2), 0.1% CO2, 1.0% CO2 and 2.0% CO2 concentrations. AT the end of the incubations the 50 ml samples were filtered through a 25 mm GF/F filter using vacuum filtration. The filters were placed in 15 ml plastic falcon tubes containing 10 ml of methanol, covered in aluminium foil and kept in the dark at 4 degrees C for 12 hours. Chl a concentration was measured using a 10AU Turner fluorometer following the acidification method of Strickland and Parsons (1972). Data in spread sheet shows the extracted chl + phaeophytin, phaeophytin and chlorophyll concentrations (micro grams l-1) for each of the three experiments. Data were collected at SIPEX Ice Stations 1-8 and SIPEX CTD stations 2-5