The dataset contains raster files (.grd) for food-availability and predicted distribution of suspension feeder abundances averaged across a five year time-period before (2005-2009) and after (2011-2016) the calving of the Mertz Glacier Tongue in 2010. The following data are included: - sinking, settling and horizontal flux of food-particles along the seafloor - suspension feeder abundances and standard deviation of the predicted distribution All data has been generated as part of the paper: Jansen et al. (2018) Mapping Antarctic suspension feeder abundances and seafloor-food availability, and modelling their change after a major glacier calving. Frontiers in Ecology and Evolution

Metadata record for data from ASAC Project 2784 See the link below for public details on this project. This project utilised an existing 55 year model reanalysis (SODA) - so no new models were developed. The methodologies/data used are described in the referenced publications. Modelling investigations of the shoaling of iron-rich upper circumpolar deep water (UCDW) and its role in the regulation of primary production at 60-65S. Taken from the project application: We intend to utilise a number of existing data sources to study the factors leading to spatiotemporal variability in the upwelling of iron-rich UCDW in the 60-65S zone, which, as discussed above, seems critical to regional ecosystem function, and the carbon and sulphur budgets of the SO. As sea-ice extent appears to have declined in the Southern Ocean since the 1950s (Curran et al., 2003) it will also be extremely interesting to examine whether this has had any affect on the upwelling of the UCDW. Given the restricted spatial domain of in situ field data in the Southern Ocean, satellite products provide us with one of the few means to investigate coherent variability over large spatial and temporal scales. This study takes advantage of our previous AAS funded work (Projects: 2584, 2319), where we have gained considerable experience in the coupling of biogeochemical and climate models and where we have already assembled satellite data sets on wind speed, sea-ice, SST, aerosols and chlorophyll-a concentration. This previous experience will allow us to examine the relationship between the physical forcings, the dynamics of the UCDW and the biological response on seasonal and interannual timescales over the period 1950-2000. The key scientific questions we seek to answer include: - What is the range of interannual and interdecadal variability in upwelling of the UCDW and how does this relate to variability in primary production? - Is there a connection between interannual/decadal variability in sea-ice extent and the strength or location of upwelling of UCDW and hence the character of regional primary production? - Is there a relation between the seasonal production of DMS and associated S-aerosols and the dynamics of UCDW? Details from previous years are available for download from the provided URL. Taken from the 2009-2010 Progress Report: Progress against objectives: This three-year project has been investigating the nexus between the large-scale meridional circulation patterns in the SO, in particular UCDW upwelling, and concomitant iron delivery to surface waters and the phytoplankton. Key Scientific Questions to be considered by the project What is the range of interannual and inter-decadal variability in upwelling of the UCDW and how does this relate to variability in primary production? This study initially focussed on the Australian region of the Southern Ocean (110-160 degrees S, 40-70 degrees E) and the physical oceanographic data for the project came from monthly Simple Ocean Data Assimilation (SODA) reanalysis data, which covers the period 1958-2007 over the global ocean. Decadal-scale trends in upper ocean structure and meridional circulation were analysed, including the upwelling of nutrient-rich UCDW, and these results were initially documented in presentation (3) below and will shortly be published in publication (1) listed below. The project identified UCDW in SODA using temperature and density criteria and, using this, a number of variables were developed to characterise UCDW and its upwelling: UCDW vertical velocity, temperature, density and salinity, UCDW top depth (the shallowest depth at which UCDW is found) and UCDW southern-most position. Climatological values were found for each of the 5-degree strips in the sector and, in addition, trends were found over the period 1958-2005. Later work involved comparing these results with those of two more Southern Ocean sectors - one in the Pacific (130-80 degrees W) and one in the Indian Ocean (20-60 degrees E). These results were presented at the AMOS conference in January 2010 (see Presentation (1) below) and are also the subject of a paper in the Proceedings of that conference (see Publication (2) below). It was found that during 1958-2005: (1) UCDW top depth varies seasonally, peaking in March, and displays considerable interannual variability; (2) Climatological properties for UCDW variables such as temperature, vertical velocity and upwelling depth vary between the three ocean sectors, as do trends (1958-2005) in the UCDW variables; (3) UCDW vertical velocity (ie. upwelling) appears to be increasing with time in most intermediate and deep waters of the three ocean sectors; (4) UCDW temperature is increasing in intermediate waters in the Pacific sector, at all depths in the Indian sector and at shallow depths in the Australian sector, but is decreasing in intermediate and deep waters in the Australian sector; (5) UCDW southern-most position is moving south in the Australian and Pacific sectors; (6) UCDW is upwelling closer to the surface in the Australian and Indian sectors and, in the case of the Australian sector, this translates into an increase in the number of times that UCDW can be detected in the mixed layer (a finding of possible importance for primary production); (7) UCDW trends in the Australian sector do not appear to be affected by trends in the winds, but by forcings acting on longer than decadal time-scales. This is not the case, however, for the other two sectors, leading to the speculation that these variables may be affected by the re-entry into UCDW of recirculated waters from the Indian and Pacific Oceans, which may themselves be affected by winds. (8) The Australian sector of the SO has been shown to have its own unique characteristics, distinct from either the Pacific or Indian sectors. More recent work has involved looking at the initial Australian sector considered above, over the period of the high resolution satellite data capture era (1997-2007), with the aim of using satellite data on chlorophyll a (chl a), sea-ice concentration and photosynthetically active radiation (PAR), as well as modelled data for primary production (PP), in addition to the reanalysis data, to look at factors that influence chl a and PP over that time period. Initial work was presented at the AMOS conference in January 2009 (see Presentation (2) below) and final work is reported in Publication (3) listed below, which is almost ready for submission. It was found that in the Australian sector during 1997-2007: (1) The most important controls on chl a in spring are sea-ice concentration and PAR in the southern-most zones (and mixed layer depth, SST, stratification and PAR in zones further north); (2) The situation is more complex in summer, especially in the southern-most zones (the areas of highest production, excluding the most northerly zone near Tasmania). In particular, in the 60-65 degrees S zone in summer, a variety of inter-acting controls affect chl a (and PP), including SST, stratification and UCDW top depth; (3) The number of times that UCDW is detected in the mixed layer is decreasing in summer during 1997-2007; (4) It is difficult to identify trends that are statistically significant over such a short time period and trends that are found are often opposite in sign to those for 1958-2005 and up to an order of magnitude larger. Thus care needs to be taken with trends found for chl a, PP and hydrodynamic variables over the short period of the satellite era, since there is a large range of such ten-year trends in the period 1958-2005. Is there a connection between interannual/decadal variability in sea-ice extent and the strength or location of upwelling of UCDW and hence the character of regional primary production? Given that UCDW upwells south of the Polar Front and no further south than the Southern Boundary of the ACC (approximately 65 degrees S in this sector), then UCDW, as identified here in its pure form, is not able to affect the 65-70 degrees S zone (although this is possible in its modified form, which is not studied here). It was found that, for the period 1997-2007 in the Australian sector of the SO, the southern-most position of UCDW is not correlated with sea-ice concentration, but that there are weak (90% level) correlations in 60-65 degrees S between UCDW top depth and sea-ice concentration in autumn (positive), the temperature of UCDW and sea-ice concentration in summer (positive) and northward Ekman transport and sea-ice concentration in summer (negative). It was found that, for 1997-2007 in the Australian sector of the SO, sea-ice concentration has a significant (inverse) relationship with chl a and PP in 60-70 degrees S in spring and 65-70 degrees S in summer. In addition, UCDW top depth and northward Ekman transport (ie. how quickly the UCDW nutrients are transported northwards and away from the zone) have a minor effect on chl a in 60-65 degrees S in summer.

Three experiments were performed at Davis Station, East Antarctica, 77 degrees 58' E, 68 degrees 35' S to determine the effects of ocean acidification on natural assemblages of Antarctica marine microbes (bacteria, viruses, phytoplankton and protozoa). Incubation tanks (6 * 650 L minicosms) were filled on the 30/12/08, 20/01/09 and 09/02/09 with sea water that was filtered through 200 microns mesh to remove metazoan grazers. The pH of each tank was adjusted by adding calculated amounts of CO2 saturated sea water. Treatment concentrations were maintained daily and microbial communities incubated for up to 12 days. The three experiments spanned early-, mid- and late-summer, with CO2 treatments ranging from pre-industrial to post-2100. The Excel spreadsheet contains 3 tabs: Experiment 1 - Early Summer Experiment 2 - Mid Summer Experiment 3 - Late Summer Within each tab there are measurements for: pCO2, dissolved inorganic carbon, Pmax, alpha, Ek, chl a, gross primary production (14C), bacterial production (14C), cell-specific bacterial productivity, bacterial abundance, dissolved organic carbon, particulate organic carbon, heterotrophic nanoflagellates, nitrate+nitrite, phosphate, silicate, ammonium, net community production, respiration, gross primary production (O2), photosynthesis:respiration ratios. Units for each measurement supplied within. Please see the following paper for interpretation of this data: Westwood, K.J., Thomson, P.G., van den Enden, R., Maher, L., Wright, S.W., Davidson, A.T. (2018). Ocean acidification impacts primary and bacterial production in Antarctic coastal waters during austral summer. Journal of Experimental Marine Biology and Ecology 498: 46-60, doi: 10.1016/j.jembe.2017.11.003.

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.

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 metadata record is the parent umbrella under which data from the 2008/09, 2013/14 and 2014/15 summer will be housed. See the child records for access to the data. Manmade CO2 has increased ocean acidity by 30% and it is projected to rise 300% by 2100. Antarctic waters will be amongst the earliest and most severely affected by this increase. Microbes are the base of the marine food chain and primary drivers of the biological pump. This project will incubate natural communities of Antarctic marine microbes in minicosms at a range of CO2 concentrations to quantify changes in their structure and function, the physiological responses that drive these changes, and provide input to models that predict effects on biogeochemical cycles and Antarctic food webs

Metadata record for data from AAS (ASAC) project 3132. Public This research will determine variability in the influx and mineralogy of cosmic dust to the Southern Ocean during the Holocene from peat bog cores. Cosmic dust contains significant quantities of soluble iron, a micronutrient required for photosynthesis. Therefore, variations in the deposition of cosmic dust could significantly affect primary production in the Southern Ocean. This may also play an important role in global climate due to its influence on carbon dioxide draw-down from, and emission of volatile sulphur compounds to, the atmosphere. The download file contain a csv spreadsheet of carbon dating from geochemical peat cores collected from Green Gorge on Macquarie Island. Project objectives: This project will sample peat bogs on Macquarie Island to: 1. Quantify and develop a high-temporal resolution record of the variability in cosmic dust deposition during the Holocene; 2. Determine the mineralogy and quantify the solubility of iron contained in the cosmic dust; Iron is a micronutrient required for photosynthetic reactions within chloroplasts. Martin [1990] proposed that many oceanic phytoplankton, especially those in the high nutrient - low chlorophyll (HNLC) regions of the world's oceans (such as the Southern Ocean) were limited by the availability of iron. Martin et al. [1991] demonstrated that nanomolar increases in dissolved iron stimulated phytoplankton blooms in the North and Equatorial Pacific and Southern Oceans. Several large-scale field experiments (see de Baar et al [2005] for a summary) demonstrated that the addition of iron stimulated phytoplankton productivity significantly. Eleven further experiments have confirmed these results in many other regions [Boyd, et al., 2007] and models of the cellular processes by which iron fertilisation stimulates phytoplankton blooms are now available [Fasham, et al., 2006]. The response of phytoplankton to iron fertilisation has attracted much research effort because phytoplankton blooms increase the draw-down of carbon from the atmosphere and ultimately export a fraction to the deep ocean where it is stored as particulate organic carbon [Watson, et al., 2000] and hence may play an important role in climate. Cosmic and terrestrial dust can both contain significant quantities of soluble, bio-available iron [Fung, et al., 2000; Plane, 2003]. The potential for iron contained in aeolian terrestrial dust to affect climate was recently assessed by Kohfeld et al. [2005], who concluded that dust-induced iron-fertilisation of ocean ecosystems might account for 30 - 50 ppm of atmospheric CO2 draw-down during the last glacial period. Satellite data provide support for these hypotheses at the regional scales at which terrestrial dust deposition events occur [Cropp, et al., 2003; Gabric, et al., 2002]. The influx of cosmic dust to the oceans could be significantly different to terrestrial dust inputs as it is likely to be uniformly distributed around the globe [Johnson, 2001], vary on longer time scales (although this is not well understood [Winckler and Fischer, 2006]), and is expected to be of finer particle-size and contrasting mineralogy [Plane, 2003]. Ice cores provide excellent long-term records of terrestrial and cosmic dust deposition, however, cores from ombrotrophic peat bogs, that receive their inputs exclusively from the atmosphere, can provide high temporal resolution records of cosmic and terrestrial dust during the Holocene [Cortizas and Gayoso, 2002]. Data from ice cores in Greenland and ocean sediment cores in the tropical Pacific have revealed variations in cosmic dust influx between glacial and inter-glacial periods, with increases in cosmic dust influx associated with cooler temperatures [Dalai, et al., 2006; Gabrielli, et al., 2004; Karner, et al., 2003]. Johnson [2001] calculated that the current background cosmic dust deposition of about 40,000 tonnes per annum delivered 30-300% of the aeolian iron flux due to terrestrial dust and about 20% of the upwelled iron flux in the Southern Ocean. Ombrotrophic peatlands, such as those found on Macquarie Island, which receive inputs of material solely from the atmosphere, provide especially useful records of cosmic dust deposition over the Holocene. Taken from the 2009-2010 Progress Report: Progress against objectives: Peat core samples were collected on Macquarie Island in April 2010. These samples will be analysed over the coming year.

The Sub-Antarctic Zone (SAZ) in the Southern Ocean provides a significant sink for atmospheric CO2 and quantification of this sink is therefore important in models of climate change. During the SAZ-Sense (Sub-Antarctic Sensitivity to Environmental Change) survey conducted during austral summer 2007, we examined CO2 sequestration through measurement of gross primary production rates using 14C. Sampling was conducted in the SAZ to the south-west and south-east of Tasmania, and in the Polar Frontal Zone (PFZ) directly south of Tasmania. Despite higher chlorophyll biomass off the south-east of Tasmania, production measurements were similar to the south-west with rates of 986.2 plus or minus 500.4 and 1304.3 plus or minus 300.1 mg C m-2 d-1, respectively. Assimilation numbers suggested the onset of cell senescence by the time of sampling in the south-east, with healthy phytoplankton populations to the south-west sampled three week earlier. Production in the PFZ (475.4 plus or minus 168.7 mg C m-2 d-1) was lower than the SAZ, though not significantly. The PFZ was characterised by a defined deep chlorophyll maximum near the euphotic depth (75 m) with low production due to significant light limitation. A healthy and less light-limited phytoplankton population occupied the mixed layer of the PFZ, allowing more notable production there despite lower chlorophyll. A hypothesis that iron availability would enhance gross primary production in the SAZ was not supported due to the seasonal effect that masked possible responses. However, highest production (2572.5 mg C m-2 d-1) was measured nearby in the Sub-Tropical Zone off south-east Tasmania in a region where iron was likely to be non-limiting (Bowie et al., 2009). Table 1:Gross primary production at each CTD station and associated data; Mixed layer depth (Zm, m), incoming PAR (mol m-2 d-1), vertical light attenuation (Kd, m-1), euphotic depth (Zeu, m), differences between euphotic depth and mixed layer depth (Zeu-Zm, m), column-integrated chlorophyll a (0 to 150 m, mg m-2), column-integrated production (0 to 150 m, mg C m-2 d-1), production within the mixed layer (mg C m-2 d-1), production below the mixed layer (mg C m-2 d-1), production within the euphotic zone (1% PAR, mg C m-2 d-1), production below the euphotic zone (mg C m-2 d-1). Kd values that were calculated from chlorophyll a v PAR regressions are marked with an asterisk. At some stations there was a surface mixed layer as well as a secondary mixed layer and both depths are indicated. Table 2:Photosynthetic attributes of phytoplankton with depth at each CTD station; Mixed layer depth (m), euphotic depth (Zeu, m), maximum photosynthetic rate [Pmax, mg C (mg chl a)-1 h-1], maximum photosynthetic rate corrected for photoinhibition [Pmaxb, mg C (mg chl a)-1 h-1], initial slope of the light-limited section of the P-I curve [alpha, mg C (mg chl a)-1 h-1 (micro-mol m-2 s-1)-1], rate of photoinhibition [beta, mg C (mg chl a)-1 h-1 (micro-mol m-2 s-1)-1], intercept of the P-I curve with the carbon uptake axis [c, mg C (mg chl a)-1 h-1], light intensity at which carbon-uptake became saturated (Ek, micro-mol m-2 s-1), and chlorophyll a measured using HPLC (mg m-3).

Metadata record for data from AAS (ASAC) project 3046. Public The overall objective is to characterise the response of Southern Ocean calcareous zooplankton to ocean acidification resulting from anthropogenic CO2 emissions. Simulated increases in anthropogenic CO2 suggest a reduction in the calcification rates of calcareous organisms. A change in the calcification in the Southern Ocean may cause marine ecosystem shifts and in turn alter the capacity for the ocean to absorb CO2 from the atmosphere. We plan to take advantage of naturally-occurring, persistent, zonal variations in Southern Ocean primary production and biomass to investigate the effects of CO2 addition from anthropogenic sources on Southern Ocean calcareous zooplankton communities. A download file containing an excel spreadsheet of data can be found at the provided URL. Project objectives: The overall objective of this project is to characterise the impacts of recent, primarily anthropogenic, increases in atmospheric CO2 and related changes in the carbonate chemistry on shell formation by calcareous zooplankton in the Australian sector of the Southern Ocean. Calcareous zooplankton (e.g. planktonic foraminifera and pteropods) will be collected using plankton nets at five Southern Ocean localities during high seasonal flux periods. Planktonic foraminiferal and pteropod species and abundances, calcification rates and geochemistry (stable isotope and trace-metal) will be determined on plankton tow samples. Data from recent plankton tow samples will be compared with data deposited historically in the Southern Ocean and recovered from existing deep ocean sediment cores to provides insights about the extent to which modern carbon conditions may have already generated ecological impacts. The project will also provide a baseline of the present-day impact of ocean acidification and can be used to monitor the influence of future anthropogenic CO2 emissions in Southern Ocean ecosystems. Taken from the 2008-2009 Progress Report: Progress against objectives: Because of logistical delays to the Aurora Australis shipping schedule, ship time for this project was deferred to the 2009/2010 season. We have made progress in analysing other materials form previous voyages which will assist in the sampling design for the upcoming season. We are making good progress in planning the upcoming voyage currently scheduled for late 2009. Taken from the 2009-2010 Progress Report: Progress against objectives: Project scientists participated in Voyage 2 of the Aurora Australis, from Hobart to Casey Station in December 2009. Using the Rectangular Midwater Trawl we collected a total of eight plankton samples for examination of calcareous plankton distribution and shell characteristics in the summer Southern Ocean. We were targeting pteropods and planktonic foraminifera, two sets of calcifiers whose calcification response to ocean acidification we had previously reported on in publications in Nature Geoscience, Biogeosciences Discussions, and Deep-Sea Research Part II (in press). Project participants included collaborators from Australian National University and Scottish Natural Heritage, UK. There were low abundance of planktonic calclfiers in this particular seasons and sector, but we consider the initial collection a god start. Samples included approx. 18 pteropods; other samples are still being held by Biosecurity Australia and will be examined as soon as they are released. Other samples have already been sent to researchers at the Australian Institute of Marine Science for genetic (RNA) sequencing. This latter collaboration is a key one which will help answer questions about evolutionary responses to ocean acidification; if there are genotypes which are more or less vulnerable to acidification we may already be seeing selective pressure in the ecosystem and a change in the structure of assemblages as "winners" and "losers" are differentially affected by the impact.

Sea ice covers up to 20 million km2 of the Southern Ocean. When present it supports a vigorous ecosystem that provides energy and food for all other marine organisms. Using the latest micro sensor technology, we are examining the factors that effect the productivity of this vital link in the Antarctic marine food web. New data were added to this metadata record in January 2011. These data included FRRF data collected on the CEAMARC, CASO, SIPEX and SAZ-SENSE voyages. A word document in the download file provides details about these datasets, plus those collected on Voyage 1 2009-2010, and voyage 2 2008-2009. The download file also contains a folder labelled "Older data". This data is described below: An explanation of the excel spreadsheet in the download file is as follows: Worksheet 1 is the chlorophyll data Worksheet 3 is the location data CHLOROPHYLL DATA Column A is sample name, the first letter refers to the location data in worksheet 3, the second to the ice flow number and the third to the replicate number Section refers to depth in ice core, measured from the bottom Ignore C Column D is the total volume of melted ice Column E is the volume of D that was filtered Column G is the Fluorometer reading before the addition dilute HCl Column H is the fluorometer reading after the addition of acid Column I is the calculation of chlorophyl concentration in the sample Column K is areal chlorophyll estimate Column L is the mean for the core Column N is the mean for the site Column O is the standard deviation LOCATION DATA Lat, longs and times of each sampling. The first set (B-G) refers to the time sampling started, the second (H-M) to when it finished Project objectives: - Determine the net photosynthesis and primary productivity of the phytoplankton and major sea ice algal communities of the Eastern Antarctic Sea Ice Zone (SIZ). Estimate seasonal and annual algal production and inter annual variability - Obtain data on biomass distribution and variability to establish regional relationships between ice thickness, snow cover, and biomass - Determine the effects of a) Light b) Nutrients (principally nitrate and iron) c) Temperature on photosynthesis and primary production - Determine whether the biomass and productivity of the phytoplankton and sea ice algae in winter and spring limits the biomass or growth of krill - Estimate the effects of climate change on Sea ice Zone primary production Taken from the 2008-2009 Progress Report: Progress against objectives: This project used V2, a spring voyage, to collect underway data to determine surface biomass and primary production. Biomass samples (chlorophyll a) were taken every 3 hours. Productivity estimates by PAM were also made every 3 hours. Productivity measurements by FRRF were made every 1 minute. Nutrient samples were taken at the same time as the biomass samples. Analysis of the biomass samples is complete. Preliminary analysis of the productivity data has commenced. This data is being used for a Masters project (Rob Johnson, IASOS). An iron addition experiment accompanied this monitoring. Iron was added to samples taken every 3 hours and the change in photosynthesis (maximum quantum yield) measured with a PAM. The rate of recovery from iron stress was the principal focus. Most of this data has been submitted as metadata. Using The PAM and FRRF simultaneously also enabled a comparison to be made between these different ways of measuring photosynthesis. Progress was also made on the analysis of FRRF productivity and biomass data collected over several years on the L'Astrolabe transect. Analysis involves quantitative manipulation of FRRF data and correlation with chlorophyll, nutrients, temperature and other biological parameters. A publication arising from this work will be submitted this year. Taken from the 2009-2010 Progress Report: Progress against objectives: We participated in V1 of the Aurora Australis, spring 2009. The objective of this project was to measure surface primary production off East Antarctica. Photosynthetic parameters of phytoplankton under actinic light (L) as well as in darkness (D) were measured using a fast repetition rate fluorometer (FRRF). The parameters included the maximum photochemical efficiency (Fv/FmL,D), the functional absorption cross section of photosystem II (sPSII,L,D) and a turnover time of electron transfer (tL,D). Chlorophyll a concentration was measured by using Turner fluorometer. The photosynthetic parameters, irradiance and chlorophyll a concentration will then be used to estimate primary production of phytoplankton. This field program particularly focussed on the first of the listed objectives, ie 'Determine the net photosynthesis and primary productivity of the phytoplankton and major sea ice algal communities of the Eastern Antarctic Sea Ice Zone (SIZ). Estimate seasonal and annual algal production and inter annual variability'. We have been collecting FRRF-based primary production data from each season and the 2009 data provides the late spring data to supplement data from autumn, winter and summer, collected in previous seasons. We have now built up a comprehensive assessment of season variability which will enable a reliable estimate of annual primary production. These analyses will also provide a detailed snap shot of primary production with which to compare future changes. Preliminary analysis shows clear patterns of variation in Fv/Fm, a parameter that is particularly sensitive to low iron concentration. This data is shown on an accompanying diagram. Productivity analysis is still underway. Much of the work for this project forms part of the PhD project of Cheah Wee.Wee is expected to finish his PhD by December 2010 and it is anticipated that all data analysis for the project will have been completed and the finished manuscripts submitted for publication. He has already had one manuscript form this project accepted (Cheah et al, 2010).