Human impacts threaten not only species, but also entire ecosystems. Ecosystems under stress can collapse or transition into different states, potentially reducing biodiversity at a variety of scales. Here we examine the vulnerability of shallow invertebrate-dominated ecosystems on polar seabeds, which may be threatened for several reasons. These unique communities consist of dark-adapted animals that rely on almost year-round sea-ice cover to create low-light shallow marine environments. Climate change is likely to cause early sea-ice break-out in some parts of Antarctica, which will dramatically increase the amount of light reaching the seabed. This will potentially result in ecological regime shifts, where invertebrate-dominated communities are replaced by macroalgal beds. Habitat for these endemic invertebrate ecosystems is globally rare, and the fragmented nature of their distribution along Antarctic coast increases their sensitivity to change. At the same time, human activities in Antarctica are concentrated in areas where these habitats occur, compounding potential impacts. While there are clear mechanisms for these threats, lack of knowledge about the current spatial distribution of these ecosystems makes it difficult to predict the extent of ecosystem loss, and the potential for recovery. In this paper we describe shallow ice-covered ecosystems, their association with the environment, and the reasons for their vulnerability. We estimate their spatial distribution around Antarctica using sea-ice and bathymetric data, and apply the IUCN Red List of Ecosystems criteria to formally assess their vulnerability. We conclude that shallow ice-covered ecosystems should be considered near threatened to vulnerable in places, although the magnitude of risk is spatially variable. This dataset comprises two files. Both are provided in netCDF format in polar stereographic project (see nc file for projection details). light_budget_6km.nc : this gives the estimated annual light budget (in mol photons/m^2/year) at the surface of the water column, having been adjusted for sea ice cover (see paper for details). This is calculated on the 6.25km grid associated with the sea ice concentration data. benthic_light_500m.nc : this gives the estimated annual light budget (in mol photons/m^2/year) at the sea floor, having been further adjusted for water depth. It is provided on a 500m grid (as per the IBCSO bathymetry used). Areas deeper than 200m are given no-data values, and areas outside of the coverage of the sea ice grid are assigned a value of -999. See paper for details.

Mineralogy data collected from the CEAMARC-CASO voyage of the Aurora Australis during the 2007-2008 summer season. The data consist of a large number of images, plus documents detailing analysis methods and file descriptions. Taken from the "Methods" document in the download file: CEAMARC MINERALOGY METHODS Margaret Lindsay August 2009 Mineralogy sampling method: (numbers in brackets refer to image below) Individual bags containing the samples taken during the CEAMARC 2007/08 voyage (1) were emptied in to a sorting tray and slightly defrosted to enable the biota to be separated and sorted in to like biota (2). Taxonomic samples were selected to represent different species. The taxonomy sample was moved onto the bench and allocated a STD barcode, a photo was taken (3) and the image number, barcode and 'identification' of the biota was recorded. From the taxonomy sample a small (larger than 0.05g) sample of the individual was dissected, weighed (4) and bagged separately, this sub-sample became the 'mineralogy sample' that were sent to Damien Gore at Macquarie University on 21/05/2009 for mineralogy analysis by Damien Gore and Peter Johnston. Samples were tracked using the Sample Tracking Database (located \\aad.gov.au\files\HIRP\new-shared-hirp\30 Samples tracking + LIMS (Lab Inf Management Sys)\Sample Tracking Database\HIRP STD Working). The key barcodes are: The nally bin's containing the CEAMARC samples are located in reefer 1 (-20 C) (barcode 11919). The original CEAMARC samples (parent container) are in nally bins 14762 and 14759. The taxonomy samples are in a nally barcoded as 70469 (contains 10 bags). The mineralogy samples are in a nally bin barcoded 70472 (contains three bags) and are currently at Macquarie University for mineralogy analysis. Data was entered during the lab process into the spreadsheet file - Sub sampling taxonomy and mineralogy.xls the details of the spreadsheets contents; The list below describes each column in the 'Taxonomy and Mineralogy', 'bamboo coral' and 'other analyses' sheets from the excel file - Sub sampling taxonomy and mineralogy.xls (location described in G:\CEAMARC\CEAMARC MINERALOGY FILE DESCRIPTIONS.doc) Date sampled Date that the taxonomic samples were dissected to obtain the mineralogy samples Parent barcode STD barcode for the nally bin that the samples are located in Site barcode STD barcode for the CEAMARC site and deployment CEAMARC site number CEAMARC voyage sample site number CEAMARC event number The CEAMARC voyage event number is the sampling devices deployment number, related to CEAMARC site number Taxonomy bag barcode STD barcode for the bag that contains the taxonomy samples Image number The image number of the taxonomy sample in it's entirety before dissected to obtain the mineralogy sample. Image contains the label from the initial sample and the sub sample barcode (for taxonomy) Sub sample barcode (for taxonomy) The STD barcode allocated to the taxonomy sample Analyses label for mineralogy The number (identical to sub sample barcode number) that identifies the mineralogy sample and links it back to the taxonomic sample. Analysis sample weight The weight in grams of the dissected part that is the mineralogy sample. Mineralogy bag barcode STD barcode for the bag that contains the mineralogy samples Identification Biota sample identification eg. Gorgonian, bryozoan, ophiuroids Mineralogy sample size Relative size of sample sent off for mineralogy analysis; small sample, medium sample or large sample. Taxonomy sample size Relative size of sample small sample; medium sample or large sample (suitable for further analysis). The 'KRILL' sheet in the above excel file has the following columns; Date sub sampled Date that the taxonomic samples were dissected to obtain the mineralogy samples Sample details Sample code used to label the krill sample Taxonomy bag barcode STD barcode for the bag that contains the taxonomy samples Image number The image number of the taxonomy sample in it's entirety before dissected to obtain the mineralogy sample. Image contains the label from the initial sample and the sub sample barcode (for taxonomy) Sub sample barcode (for taxonomy) The STD barcode allocated to the taxonomy sample Analyses label for mineralogy The number (identical to sub sample barcode number) that identifies the mineralogy sample and links it back to the taxonomic sample. Analysis sample weight The weight in grams of the dissected part that is the mineralogy sample. Mineralogy bag barcode STD barcode for the bag that contains the mineralogy samples Identification Biota sample identification eg. Gorgonian, bryozoan, ophiuroids Mineralogy sample size Relative size of sample sent off for mineralogy analysis; small sample, medium sample or large sample. Taxonomy sample size Relative size of sample small sample; medium sample or large sample (suitable for further analysis). Voyage The ANARE Voyage number and year is expressed as V4 02/03 Station Station number that the samples were obtained from Date Date that the samples were taken during the voyage Time Time that the samples were taken during the voyage Location Location that the samples were taken from during the voyage Net The RMT 8 and 1 were used to collect the krill Depth The depth that the samples were obtained from (25 meters) Total mineralogy samples 1033 mineralogy samples + 15 bamboo coral samples (+ 12 krill samples) = 1060 samples

Image data (both stills and video) collected from the CEAMARC-CASO voyage of the Aurora Australis during the 2007-2008 summer season. The data consist of a large number of images, plus documents detailing analysis methods, file descriptions and an AMSA (Australian Maritime Safety Authority) report.

A total of 701 still images were analysed from 10 transects on the Sabrina Coast continental shelf. Imagery was collected from the RVIB Nathaniel B Palmer (NBP 14-02, 29 January - 16 March 2014) across a greater than 3000 km2 area. A 'yoyo' camera, with downward facing digital still and video cameras mounted within a tubular steel frame, was deployed on a coaxial cable to image the seafloor. The Ocean Imaging Systems DSC 10000 digital still camera (10.2 megapixel, 20 mm, Nikon D-80 camera) was contained within titanium housing. Camera settings were: F-8, focus 1.9 m, ASA-400. An Ocean Imaging Systems 3831 Strobe (200 W-S) was positioned 1m from the camera at an angle of 26 degrees from vertical. A Model 494 bottom contact switch triggered the camera and strobe at 2.5m above the sea floor, imaging ~ 4.8m2 of sea floor. Parallel laser beams (10 cm separation) provided a reference scale for the images. Transects were conducted at a ship's speed of ~1 knot. Still images were characterised for main taxonomic groups and sediment properties based on the CATAMI scheme of Althaus et al. 2015.