As part of the Scott Base Redevelopment Marine Monitoring Programme, the impact of Scott Base's activities on the local marine environment was assessed. Sampling took place at three sites around Hut Point Peninsula on the southern half of Ross Island during October – November 2019 to assess anthropogenic contamination. Two acoustic doppler current profilers (ADCP; Nortek Signature 500) were deployed, and set with a 2-minute sampling period in 1m vertical depth bins from the seabed to the underside of the ice. Instrument heads were kept ~0.5 m beneath the under-surface. ADCP data were downloaded, extracted from their raw formats, and averaged into 10-minute intervals. A magnetic declination of 141.09° E was applied to the measured current direction to correct the readings to reflect true north and a pressure offset was applied to standardise depths relative to ambient air pressure at the seawater surface. Information on habitats and benthic epifauna assemblage composition were collected using high resolution video across 2 25m transects at ~22m depth. Multiple overlapping passes were made across the seabed transects at ~0.5 m depth contours between ~20 – 26 m in order to create a 2D orthomosaic image of each site. Analysis of the diver-collected video was done using individual frames. The video along each transect was divided into 10 equal time segments and still frames were taken at random from the first, third, fifth, seventh and ninth segments. Eight video frames were analysed per transect (i.e., n=8 per transect and n=16 per site) by one individual to minimise observer bias. Sediment samples were collected by divers to determine contaminant concentrations and sediment characteristics (sediment particle size composition, organic matter content, organic carbon content and algal pigment content) at each site. Sponge species (Sphaerotylus antarcticus and Laternula elliptica) were collected for tissue contaminant analysis. Full description of methods is available at: https://doi.org/10.1007/s00300-023-03181-1 GET DATA: drew.lohrer@niwa.co.nz

This metadata record represents environmental DNA sequence data and metadata barcode file. Seawater and sponge eDNA metabarcoding sampling was conducted at seven coastal locations (Cape Barne, Cape Evans, Cziko Seamount, Granite Harbor Middle, Granite Harbor South, and Turtle Rock) in the Ross Sea to assess spatial eukaryote biodiversity patterns and investigate eDNA signal differences between both substrates. Five replicate 500 mL water samples were collected at each of seven locations within 2 m of the ocean floor using a Niskin bottle. At the same time, five sponge specimens were collected by ROV at a depth range of 18–30 m from three out of the seven locations, thereby enabling sponge and near-bottom water eDNA signal comparison. Further details and laboratory procedures can be found in https://doi.org/10.1002/edn3.500 GET DATA: https://figshare.com/projects/Unveiling_the_Hidden_Diversity_of_Marine_Eukaryotes_in_the_Ross_Sea_A_Comparative_Analysis_of_Seawater_and_Sponge_eDNA_Surveys/186127