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.

Overview The aim of the project was to assess the genetic connectivity of benthic amphipods (crustaceans) on a circumantarctic scale. Two sibling amphipod species were chosen as the subjects for this study: Eusirus perdentatus and Eusirus giganteus. Samples of both species were collected (or donated by other institutions) from five broad regions of the Antarctic coast (see 'Sample location information' worksheet). The dataset we generated represents DNA sequences we obtained from these amphipods. Each amphipod was sequenced for three gene regions - these were cytochrome oxidase subunit I (COI), internal transcribed spacer 2 (ITS2) and cytochrome b (CytB). Each DNA sequence generated has been deposited on the publicly-accessible GenBank website (www.ncbi.nlm.nih.gov/genbank/) and therefore has its own accession number (which can be typed into the GenBank search bar to access the actual DNA sequence in .fasta format). The attached spreadsheet provides details on the location, depth and date of each amphipod sample collected, the preliminary species ID for each amphipod*, and the resultant DNA sequences corresponding to each of the three gene regions amplified (these are provided as Genbank accession numbers). *Results of this project have actually highlighted that Eusirus perdentatus and Eusirus giganteus almost certainly contain several extra cryptic species, therefore these ID's are likely to be revised in the future. Data collection and analysis The full methodology used to generate and analyse the DNA sequences prior to their deposition on Genbank can be found in the associated publication (see below). Most amphipod samples were collected between January 2007 and January 2010. However, a small proportion of the samples were collected on Polarstern voyages that took place in February 2002 and December 2003-January 2004. Genetic data was generated and analysed between June 2008 and May 2010. Circumantarctic DNA sequences obtained from two amphipod species, Eusirus perdentatus and Eusirus giganteus - DNA sequences obtained from two sibling amphipod species, Eusirus perdentatus and Eusirus giganteus. Samples of both species were collected (or donated by other institutions) from five broad regions of the Antarctic coast: Tressler Bank, East Coast, Ross Sea, Antarctic Peninsula and Weddell Sea. Collection dates ranged from 2002 to 2010. Sample location information is included. Explanation of spreadsheet Worksheet: 'Samples and genetic data' This worksheet contains all of the actual data generated, although rather than providing entire genetic sequences, we provide the Genbank accession number which can be used to access the sequence online (as explained above). The column headings are as follows: Sample ID- a unique code given to each amphipod sample as a form of identity. Morphological ID- the species identification for each amphipod, as determined morphologically (i.e. the genetic data has since illuminated that these IDs may need revision in the future). Sampling site- a code for the exact location from which each amphipod was sampled. For details on these locations, refer to 'Sample location information' worksheet, which uses the same codes. DNA sequence (Genbank accession number)- Genbank accession numbers for the DNA sequences obtained from each amphipod. The three columns within this represent the three gene regions we sequenced: COI (cytochrome oxidase subunit I), CytB (cytochrome b) and ITS2 (internal transcribed spacer 2). Occasionally one of these gene regions would fail to amplify in a particular sample, or the sequence was ambiguous, therefore not all amphipod samples have an accession number for all three gene regions. Worksheet: 'Sample location information' This worksheet provides the details on the actual collection of the amphipod specimens. Column headings are as follows: Sampling site- the code for each site from which amphipods were sampled, as used in the previous worksheet. Latitude- coordinates for each sampling site. Longitude- coordinates for each sampling site. Depth range of trawl (m)- As all amphipod samples were collected in benthic trawls deployed from research vessels, this column provides the depth range of the seabed over which each trawl was dragged. Collection date- the month and year in which each site was sampled. Region of Antarctic coast- the broad geographic region of the Antarctic coastline into which each set of sampling sites is grouped. Research vessel- the research vessel from which benthic trawls were deployed to collect the amphipods at each site. Note that for each broad geographic region, a single vessel was responsible for collecting all samples.

During RV Polarstern voyage PS117, under-ice observations were conducted with an instrumented Remotely Operated Vehicle (ROV) deployed directly from the ship. Collected time-stamped datastreams from the instrumented ROV include: ROV navigation data (heading, pitch, roll, position from an acoustic transponder system), under-ice video footage from the ROV camera and additional upward-looking video cameras, data from an upward-looking acoustic altimeter with integrated depth sensor (to measure the distance of the ROV to the sea-ice subsurface), under-ice hyperspectral irradiance and radiance data from two upward-looking radiometers, and time-stamped up-ward looking digital stills images to detect and quantify the abundance of herbivores at the ice-water interface. Methods for data collection are broadly consistent with methods described in detail in the referenced publication.

Data are "phytoplankton counts" for each phytoplankton taxon observed, from the CPR samples collected by the Southern Ocean CPR Survey projects 472 and 4107 (Hosie et al. 2003). The SAHFOS on-silk phytoplankton count method is used (Batten et al. 2003). Phytoplankton are identified to the best taxonomic level possible, ideally to species or at least genus, in 20 fields of view (295 plus or minus 10 microns) per sample (section of silk). See Figure 2 of Batten et al. (2003). Each sample usually represents 5 nautical miles for SO-CPR. The "phytoplankton count" is the number of fields of view where a phytoplankton species/ taxon was observed, recorded for each taxon for each sample. It is effectively a frequency of occurrence score. The CPR is a device towed at normal ship speed, approximately 100 m behind the ship at a depth of 8-10 m. Plankton enter a small aperture 12.7 x 12.7 mm which then expands into a tunnel 100 x 50 mm reducing the speed by about 1/30. Plankton are then sandwiched between two sheets of 270 micron silk gauze, before rolling into a preservation tank of formaldehyde. Each tow is approximately 450 nautical miles. Regardless of ship speed the silk advances at a fixed rate of about 1 cm per nautical mile. Silks are cut into 5 nautical mile equivalent lengths and both phyto- an zooplankton are counted. Each sample is coded with time and date (GMT) and latitude and Longitude, plus averaged environmental data over the 5 nautical miles, e.g. water temperature, salinity, fluorescence, light. Zooplankton data and methods are described in Metadata record AADC-00099. Abbreviations CPR, Continuous Plankton Recorder SAHFOS, Sir Alister Hardy Foundation for Ocean Science SO-CPR , Southern Ocean CPR Survey

These data describe pack ice characteristics in the Antarctic sea ice zone. These data are in the ASPeCt format. National program: Germany Vessel: Polarstern Dates in ice: 14 Jan 1997 - 28 Feb 1997 Observers: Unknown (Christian Haas and others ?) Summary of voyage track: 14/1 Ice edge at 69'39S 13'14W 14-31/1 Eastern Weddell Sea to south-eastern Weddell Sea return 1-18/2 Eastern Weddell Sea to western Weddell Sea (Antarctic Peninsular at 60S) 19-28/2 Western Weddell Sea to south-eastern Weddell Sea The fields in this dataset are: SEA ICE CONCENTRATION SEA ICE FLOE SIZE SEA ICE SNOW COVER SEA ICE THICKNESS SEA ICE TOPOGRAPHY SEA ICE TYPE RECORD DATE TIME LATITUDE LONGITUDE OPEN WATER TRACK SNOW THICKNESS SNOW TYPE SEA TEMPERATURE AIR TEMPERATURE WIND VELOCITY WIND DIRECTION FILM COUNTER FRAME COUNTER FOR FILM VIDEO RECORDER COUNTER VISIBILITY CODE CLOUD WEATHER CODE COMMENTS

These data describe pack ice characteristics in the Antarctic sea ice zone. These data are in the ASPeCt format. National program: Germany Vessel: Polarstern Dates in ice: 12 Jun 1992 - 31 Jul 1992 Observers: Unknown (Christian Haas and others ?) Summary of voyage track: 12/6 Ice edge at 60'56S 0W 12-18/6 Transect south down 0W to coast 18/6 - 8/7 Transect SW around coast 8-21/7 Transect to South Orkney Islands 24-31/7 Transect to northern Antarctic Peninsular 31/7 Ice edge at 61'11S 57'45W The fields in this dataset are: SEA ICE CONCENTRATION SEA ICE FLOE SIZE SEA ICE SNOW COVER SEA ICE THICKNESS SEA ICE TOPOGRAPHY SEA ICE TYPE RECORD DATE TIME LATITUDE LONGITUDE OPEN WATER TRACK SNOW THICKNESS SNOW TYPE SEA TEMPERATURE AIR TEMPERATURE WIND VELOCITY WIND DIRECTION FILM COUNTER FRAME COUNTER FOR FILM VIDEO RECORDER COUNTER VISIBILITY CODE CLOUD WEATHER CODE COMMENTS

These data describe pack ice characteristics in the Antarctic sea ice zone. These data are in the ASPeCt format. National program: Germany Vessel: Polarstern Dates in ice: 12 Dec 2000 - 22 Dec 2000 Observers: Gerd Rohardt, others Summary of voyage track: North-south sections near the prime meridian from the ice edge to Neumeyer station and back to the ice edge. The fields in this dataset are: SEA ICE CONCENTRATION SEA ICE FLOE SIZE SEA ICE SNOW COVER SEA ICE THICKNESS SEA ICE TOPOGRAPHY SEA ICE TYPE RECORD DATE TIME LATITUDE LONGITUDE OPEN WATER TRACK SNOW THICKNESS SNOW TYPE SEA TEMPERATURE AIR TEMPERATURE WIND VELOCITY WIND DIRECTION FILM COUNTER FRAME COUNTER FOR FILM VIDEO RECORDER COUNTER VISIBILITY CODE CLOUD WEATHER CODE COMMENTS

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.

These data describe pack ice characteristics in the Antarctic sea ice zone. These data are in the ASPeCt format. National program: Germany Vessel: Polarstern Dates in ice: 23 Jan 1994 - 02 Mar 1994 Observers: Unknown (Christian Haas and others ?) Summary of voyage track: 23/1 Vicinity of Adelaide Island 4-19/2 Transect (80W) into Ronne Entrance, around Bryan Coast, transect out to Peter Island (85-90W) 22-25/2 N-S transect at approx. 105W (eastern Amundsen Sea) 27/2 - 2/3 N-S transect at approx. 120W (central Amundsen Sea) The fields in this dataset are: SEA ICE CONCENTRATION SEA ICE FLOE SIZE SEA ICE SNOW COVER SEA ICE THICKNESS SEA ICE TOPOGRAPHY SEA ICE TYPE RECORD DATE TIME LATITUDE LONGITUDE OPEN WATER TRACK SNOW THICKNESS SNOW TYPE SEA TEMPERATURE AIR TEMPERATURE WIND VELOCITY WIND DIRECTION FILM COUNTER FRAME COUNTER FOR FILM VIDEO RECORDER COUNTER VISIBILITY CODE CLOUD WEATHER CODE COMMENTS