Deep-sea Microbial Dataset of the Antarctic Ocean (dsMDAO): A high-resolution deep-sea microbial dataset of the Antarctic Ocean reveals potential for taxonomic and functional diversity.

Abstract

Antarctic deep-sea ecosystems harboured unique and metabolically versatile micro-organisms that sustained key biogeochemical processes under extreme polar conditions. However, the genomic diversity and ecological functions of these sedimentary or deep-sea microbial communities remained largely unexplored. Here, we constructed a comprehensive deep-sea microbial dataset of the Antarctic Ocean (dsMDAO) by integrating three newly sequenced Prydz Bay sediment metagenomes with 22 publicly available datasets (9 seawater and 13 sediment samples), spanning water depths of ~300-3500 m. Genome binning yielded 186 metagenome-assembled genomes spanning 19 phyla, including 175 bacteria and 11 archaea, a substantial proportion of which represent previously uncharacterized species. Meanwhile, reads mapping with the available standard Kraken2 database (k2_standard) enabled the expansion of species richness of the dsMDAO database. Furthermore, functional annotation revealed diverse metabolic and ecological potentials, including carbon, nitrogen and sulphur cycling, as well as secondary metabolite biosynthesis, virulence-associated defence and cold-adaptation mechanisms. Sediment microbiomes exhibited higher phylogenetic and functional diversity, enriched in Thaumarchaeota and Chloroflexi, whereas seawater communities were dominated by Proteobacteria with more competitive biosynthetic and interaction potentials. Co-occurrence analyses further indicated complex and competitive networks in seawater versus modular and cooperative assemblages in sediments, reflecting distinct ecological strategies. Collectively, dsMDAO provides the first genome-resolved dataset of Antarctic deep-sea microbiota, revealing the hidden taxonomic and functional diversity that underpins ecosystem resilience in polar oceans. This resource lays a foundation for future ecological, evolutionary and biotechnological exploration of Antarctic microbial dark matter.