With 308.6 million gene clusters, the KMAP Global Ocean Gene Catalog 1.0 is the largest open-source catalog to date matching microbial class with gene function, geographic location, and ecosystem type.

The catalog offers diverse applications that go beyond advancing our understanding of the ocean microbiome and its metabolic capabilities—it also establishes a baseline for tracking the influence of global warming, pollution, and other changes on ocean health and provides a tool to explore marine genetic resources to discover novel genes with potential uses in medicine, energy, food, and other industries.

Fungi represented over 50% of the distinct gene clusters identified in the mesopelagic zone. This finding highlights the contribution of fungi to microbial diversity and carries functional consequences for the role of fungi in elemental cycling in the ocean.

Biomass ratios among domains are not reflective of the corresponding distribution of unique genes: this rough comparison shows that the eukaryotic component of ocean biomass outweighs its contribution to marine genetic diversity, which remains dominated by Bacteria, and that viral genomes contain far more innovation than hitherto realized, even considering that this DNA-based assessment of the global ocean genome omits RNA viruses.

Analysis of benthic and pelagic samples revealed significant differences in both taxonomic composition and metabolic processes, reflecting the heterogeneous nature of the ocean floor and highlighting the potential for uncovering a vast reservoir of functional genes, as well as the need to further sample and investigate marine benthic metagenomic resources, which remain underexplored compared with the pelagic component.