Description: Multibeam data were collected during RRS James Clark Ross cruise JR17003a (2018-02-22 to 2018-03-12). Multibeam sonar system was Kongsberg EM122. Data are unprocessed and may contain outliers and blunders and should not be used for grid calculations and charting projects without further editing. The raw multibeam sonar data in Kongsberg multibeam processing format (*.all) were recorded with Kongsberg SIS software running on Windows operating system. Kongsberg data files can be processed using the software packages CARIS HIPS/SIPS or with the open source software package MB-System.

Description: Sponges (Porifera) host diverse and species-specific communities of microbial symbionts with which they maintain tight interactions. However, knowledge on the microbiomes of sponges from deep waters and remote polar areas is still scarce, especially for the sponge class Hexactinellida. Therefore, our aim was to describe the community composition, richness and density of microbial symbionts of Antarctic deep-water sponges, including several species of hexactinellids, and relate the findings to host ultrastructure and histology. During the Antarctic expeditions PS96 (RV Polarstern, 2015/16, eastern Weddell Sea) and JR17003a (RRS James Clark Ross, 2018, western Weddell Sea), 28 sponge specimens, bottom water and sediment were sampled for molecular analysis of microbial communities. The sponges were collected from deep habitats of 290-845 m by Bottom Trawl or Agassiz Trawl and comprised 19 hexactinellids and 9 demosponges. Bottom water was collected with a CTD rosette sampler which also measured environmental data (temperature, salinity, oxygen) close to the start or end point of the trawls and at four additional stations. Sediment was collected from the Agassiz trawl together with sponge samples during JR17003a. The molecular microbiome analysis targeted bacteria and was based on 16S rRNA gene sequencing of the V3-V4 variable regions. Sequences were processed using the QIIME2 environment. Amplicon sequence variants (ASVs) were generated with the DADA2 algorithm and classified based on the Silva 132 99% OTUs 16S database. Eight sponge specimens collected during JR17003a were further investigated microscopically for microbial symbionts, sponge histology and ultrastructure. Histological sections of 7-30 µm were stained in either Masson's trichrome or Hematoxylin/Eosin and images captured on a Zeiss Axioskop 2 plus with a QiCam camera using Northern Eclipse software. Ultrastructural sections of 60 nm were stained in uranyl acetate and lead citrate and then viewed and photographed with a Philips Morgagni transmission electron microscope equipped with a Gatan CCD camera. This Data Collection includes sampling information, environmental data, NCBI accession numbers and photographs of the analyzed sponges, data on the microbial symbiont communities (amplicon sequence variants and microbial phyla) of sponges, seawater and sediment, as well as micrographs of sponge histology and ultrastructure.

Description: Multibeam data were collected during RRS James Clark Ross cruise JR17003a (2018-02-18 to 2018-03-12). Multibeam sonar system was Kongsberg EM 122 multibeam echosounder. Data are processed with Caris HIPS, including sound velocity correction with SV data from CTDs and World Ocean Atlas 09, tidal correction with TPXO9_atlas_v5 (https://www.tpxo.net/global/tpxo9-atlas), and manual cleaning. The soundings are combined in daily files, the format is XYZ ASCII (〈Lon〉 〈Lat〉 〈Depth in meters, positive up, relative to mean sea level〉). Additional blockmedian grids have been computed with depth dependent cell size to visualize the data. These grids are not meant for scientific analysis or navigation, but for overview purposes only.

Description: Peracarid abundance and composition were studied in the Atlantic Sector of the Southern Ocean and the Weddell Sea at a depth range of 403-2021 m. Samples were collected using an epibenthic sledge (EBS) during expeditions on board the RRS James Clarke Ross in the Filchner Trough (JR275), the South Orkney Islands (JR15005), the Prince Gustav Channel (JR17003a) and on board the RV Polarstern in the Eastern Antarctic Peninsula (PS118). Expeditions took place in February-March 2012, 2016, 2018 and 2019 respectively. Since the trawling distance between stations was not always the same, in order to make data comparable between different stations, numbers of individuals were standardized to 1000 m haul distances. In total 64766 peracarids were found and sorted into five different orders (Amphipoda, Cumacea, Isopoda, Mysidacea and Tanaidacea). Amphipods were the most abundant group representing the 32% of the total abundances. The Filchner Trough had the highest abundance of peracarids, while the South Orkney Islands showed the lowest abundance compared to other areas.

Description: This dataset provides metadata of bottom water samples collected for microbiome analysis during expeditions PS96 (RV Polarstern, 2015/16) and JR17003a (RRS James Clark Ross, 2018) in the Weddell Sea, Antarctica, as well as environmental data of the respective stations. It includes information on sampling locations, number of bacterial sequences and amplicon sequence variants (ASVs), and NCBI accession numbers for raw sequencing data. Environmental data of PS96 stations were obtained from: Schröder, Michael; Ryan, Svenja; Wisotzki, Andreas (2016): Physical oceanography measured on water bottle samples during POLARSTERN cruise PS96 (ANT-XXXI/2 FROSN). Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, PANGAEA, https://doi.org/10.1594/PANGAEA.859035

Description: This dataset provides metadata of Antarctic deep-water sponges (Demospongiae and Hexactinellida) and sediment collected for microbiome analysis during expeditions PS96 (RV Polarstern, 2015/16) and JR17003a (RRS James Clark Ross, 2018) in the Weddell Sea. It includes information on sampling locations, number of bacterial sequences and amplicon sequence variants (ASVs), NCBI accession numbers for raw sequencing data, and SMF collection numbers for the sponges archived in the collection of Senckenberg Museum, Frankfurt am Main, Germany.