OCES Departmental Seminar: Global distribution of diazotrophs and their characteristics

Dinitrogen (N2) fixation is the process by which specialized prokaryotes (diazotrophs) convert dinitrogen gas to ammonia. It has long been thought that N2fixation occurs mainly in the oligotrophic tropical and subtropical regions where cyanobacterial diazotrophs are prevalent. Recent studies have shown that N2fixation also occurs in the polar regions and thus is a global process, although the physiological and ecological characteristics of polar diazotrophs are not yet known. Recently, we have newly built a marine metagenome-assembled genome catalog, which contains >50,000 genomes derived from 8466 prokaryotic species that were derived from various marine oceanic regions including the Arctic Ocean. We explored the genome catalog for Arctic diazotrophic species, examined the distribution patterns of diazotrophs using a global metagenomic database, and characterized diazotrophs in the Arctic Ocean by comparative genomic analyses. This study not only elucidates the attributes of diazotrophs in the Arctic Ocean but also unveils the global distribution patterns of diazotrophs and their characteristics.