Description: This dataset provides relative abundances of microbial phyla in Antarctic deep-water sponges (Demospongiae and Hexactinellida), bottom water samples and sediment collected for microbiome analysis during expeditions PS96 (RV Polarstern, 2015/16) and JR17003a (RRS James Clark Ross, 2018) in the Weddell Sea. The 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. The first column of the table gives the observed microbial phyla; the following columns give the relative abundances of each phylum in each sample (as fraction). The first line includes the sample IDs for sponge, seawater, and sediment samples. Sample IDs for sponges are composed of abbreviations for sponge species: Anoxycalyx joubini (Aj), Inflatella belli (Ib), Isodictya lankesteri (Il), Rossella fibulata (Rf), Rossella nuda (Rn), Rossella racovitzae (Rr), Rossella vanhoeffeni (Rv), Tentorium semisuberites (Ts), and the field ID of each specimen. Sample IDs for seawater (sw) and sediment (sed) indicate the respective station.

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.

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: 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: This dataset provides amplicon sequence variant (ASV) counts of Antarctic deep-water sponges (Demospongiae and Hexactinellida), bottom water samples and sediment collected for microbiome analysis during expeditions PS96 (RV Polarstern, 2015/16) and JR17003a (RRS James Clark Ross, 2018) in the Weddell Sea. The 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. The table gives the feature IDs (unique identifier for each ASV), the counts for each ASV in each sample, and total counts for each ASV. The first line includes the sample IDs for sponge, seawater, and sediment samples. Sample IDs for sponges are composed of abbreviations for sponge species: Anoxycalyx joubini (Aj), Inflatella belli (Ib), Isodictya lankesteri (Il), Rossella fibulata (Rf), Rossella nuda (Rn), Rossella racovitzae (Rr), Rossella vanhoeffeni (Rv), Tentorium semisuberites (Ts), and the field ID of each specimen. Sample IDs for seawater (sw) and sediment (sed) indicate the respective station.