We studied the gut contents of four dominant copepod species (Calanoides acutus, Calanus propinquus, Calanus simillimus and Rhincalanus gigas) during the summer (2014-2015) along a latitudinal gradient (sampled every 5° between 40°S and 65°S) in the Indian sector of the SO. Diatoms were the most abundant food item found in the guts, comprising 24 of the 25 species found, and 15 were common to the four species of copepod studied. Diatoms accounted for the lowest proportion of the diet in the warmer, northern waters while all the large diatoms (e.g. Chaetoceros atlanticus, C. criophilus, C. dichaeta, Corethron spp.) were only found at 65oS. The most frequent species in the guts were the centric diatoms Thalassiosira spp. (4 to 57%) and the pennate diatoms Fragilariopsis kerguelensis (27 to 80%) and Trichoctoxon reinboldii (2 to 50%); proportions varied within a species across locations. These species were found at all sites examined, whereas some diatoms were specific to one copepod species: Asteromphalus spp. (in R. gigas), C. criophilus and C. dichaeta (in C. acutus), Nitzschia lecointei and N. sicula (in C. propinquus).

The dataset was developed during a cruise on the Umitaka-maru along the 110 E meridian from Fremantle to the ice edge. At five stations, zooplankton were collected and specimens selected for grazing experiments. They were added to 2L bottles, allowed to acclimate over 24 hours then placed in an onboard incubator and allowed to graze on natural phytoplankton assemblages. Water circulation around the incubator kept the temperature to that of seawater at the time of collection. Shade cloth was used to mimic the light conditions at each site. Where possible 4 replicates were run for each species and 4 control bottles were set up with the same phytoplankton assemblage but with no zooplankton added. Initial subsamples were taken and preserved in Lugol's solution. At the end of each experiment, further subsamples were taken and preserved in Lugol's solution. In the IMAS lab the phytoplankton samples were settled into smaller volumes and processed through a Coulter Counter to obtain the number of cells that had been removed by the plankton (initial conc - final conc). From those values, grazing rates of the species could be calculated for each site along the transect.

Sampling was conducted according to GEOTRACES protocols. Samples for trace element analyses, including dissolved iron (dFe), were filtered through acid-cleaned 0.2 um cartridge filters (Pall Acropak) under constant airflow from several ISO class 5 HEPA units. All plastic ware was acid-cleaned prior to use, following GEOTRACES protocols. Samples were collected into low-density polyethylene (LDPE) bottles, acidified immediately to pH 1.7 with Seastar Baseline hydrochloric acid (HCl), double-bagged and stored at room temperature until analysis on shore. Samples for dFe analysis were pre-concentrated offline (factor 40) on a SeaFAST S2 pico (ESI, Elemental Scientific, USA) flow injection system with a Nobias Chelate-PA1 column. Samples were eluted from the column in 10% distilled nitric acid (HNO3), with calibration based on the method of standard additions in seawater (made using multi-element standards in a 10% HNO3 matrix, rather than an HCl matrix). Pre-concentrated samples were analysed using Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICP-MS, Thermo Fisher Scientific, Inc.). Data were blank-corrected by subtracting an average acidified milli-Q blank that was treated similarly to the samples. The dFe detection limit for a given analysis run on the SeaFAST/SF-ICP-MS was calculated as 3 x standard deviation of the milli-Q blank on that run. Detection limits ranged from 0.016 to 0.067 nmol kg-1, with a median of 0.026 nmol kg-1 (n=12). GEOTRACES reference materials were analyzed along with samples and results were in good agreement with consensus values: SAFe D1 was measured at 0.69 +/- 0.05 nmol kg-1 (n=7; consensus value = 0.67 +/- 0.04 nmol kg-1) and GD was measured at 1.02 +/- 0.01 nmol kg-1 (n=6; consensus value = 1.00 +/- 0.1 nmol kg-1). Comments regarding the data spreadsheet: NaN = no sample dFe QC flags: 1 = high confidence in data quality 2 = detection limit 3 = low confidence in data quality detection limits: dFe data that were below the daily detection limit were replaced with the respective detection limit. They are flagged with the number 2 in the dFe QC flag column.

Australia's Census of Antarctic Marine Life project. This project is a part of the international "Census of Antarctic Marine Life" (CAML) which was conducted during the International Polar Year. It was a collaborative contribution by Australia and France to understand the biodiversity of the oceans surrounding Antarctica, with particular emphasis on the fishes of the eastern part of the Australian Antarctic Territory. The biodiversity data, when added to that obtained by all other nations participating in the CAML, serves as a robust reference for future examinations of the health of the Southern Ocean, and assists in the conservation and management of the region. Field sampling for this project was undertaken in the 2007/08 season, commencing in December and finishing in February 2008. Three ships surveyed the area with a range of traditional and modern sampling gear, including IYGPT (International Young Gadoid Pelagic Trawl (marine science equipment)) gear.

Copies of the event logs/station lists taken from the Aurora Australis, Astrolabe and Umitaka Maru during their CEAMARC cruises (collaborative East Antarctic Marine Census).

This dataset contains results from Continuous Plankton Recorder (CPR) surveys in the Southern Ocean. When the opportunity arises, zooplankton species, numbers and abundance data are recorded on a continuous basis as vessels steam through the area between Australia and Antarctica, including Heard and Macquarie Islands. Observations have been made since June 1990 and are ongoing. Obviously the observations are not continuous over the region with time. Many of the original SO-CPR logbooks from the various voyages have also been scanned, and are available via the Australian Antarctic Data Centre's Reports Register. Zooplankton have been identified to lowest possible taxon, usually species, and counted for each segment. For copepods, copepodites and for some species nauplii (e.g. Rhincalanus gigas) have been counted separately, and for euphausiids, naupliar, calyptopis and furcilia developmental stages are identified. The fields in this dataset are: Tow_number - the CPR tow number Ship_name - the name of the ship on which the tow was conducted Season - two-year Antarctic season based around the austral summer, e.g. '2000-01' runs from July 2000 to June 2001 Latitude - the decimal latitude of the segment sample Longitude - the decimal longitude of the segment sample Observation_date - UTC date and time of the segment sample in ISO8601 format (yyyy-mm-ddTHH:MMZ) Observation_date_year - the observation date year Observation_date_month - the observation date month Observation_date_day - the observation date day Observation_date_hour - the observation date hour Observation_date_minute - the observation date minute Observation_date_time_zone - the observation date time zone (0=UTC) Segment_number - the individual segment number within each tow Segment_length - the distance travelled by the CPR during this segment (nautical miles). This is the true segment length as used in the Geocoding program used to cut the silk, and to calculate positions and average environmental data for each segment. In theory, all segments are 5 nautical miles long. However, this wasn't always the case with early Aurora Australis tows, where it was assumed that each marked segment was 5 nautical miles whereas each tow had subtle variations in silk advancement, depending on the wear of the cassette or travel with or against a current. True segment length has since been recalculated. At other times, some silks have been incorrectly cut and the true length has again been recalculated. The last segment of each tow may be less than 5 nautical miles. This field can be used to standardise species counts to say 5 nautical miles or to a theoretical volume filtered by multiplying the distance travelled by aperture area (12.7 x 12.7 mm): Volume Filtered = Distance (n miles) x 1852 metres x 0.0127^2. A 5 nautical mile segment theoretically represents 1.49 m^3. Total_abundance - total count of all zooplankton in a segment Phytoplankton_colour_index - visual estimation of the green colour of the silk mesh. Values are 'No Colour', 'Very Pale Green', 'Pale Green', or 'Green'. This colouration is due to the green chlorophyll pigments derived from chloroplasts of intact and broken cells and small unarmoured flagellates. It may provide an indicator of phytoplankton standing stock, although in the Southern Ocean there are some diatoms that are quite common on the silks but as they have very low amounts of chlorophyll the colour doesn't register in the PCI analysis. Fluorescence - water fluoresence measured by the vessel, averaged for the segment (arbitrary units). See Quality notes for more information. Salinity - water salinity measured by the vessel, averaged for the segment (psu). See Quality notes for more information. Water_temperature - water temperature measured by the vessel (degrees Celsius). See Quality notes for more information. Photosynthetically_active_radiation - photosynthetically active radiation measured by the vessel (micro-Einsteins m-2 s-1). This is not available on some vessels but has been included as a useful parameter to help differentiate data from night and day. The remaining fields ('Abylidae' through to 'Vibilia_sp') are zooplankton taxon names. The entries in these columns are the counts of each taxon in the segment.