Bacteria and Archaea regulate particulate organic matter export in suspended and sinking marine particle fractions

The biological carbon pump is crucial for the export of particulate matter in the oceans. Recent studies on marine microbes have shown the profound influence of bacteria and archaea as regulators of particulate matter export. Yet, despite the importance of the Southern Ocean as a carbon sink, we lack comparable insights regarding microbial contributions. This study provides the first insights regarding prokaryotic contributions to particulate organic matter export in the Southern Ocean. We reveal evidence that prokaryotic communities in suspended and sinking particle fractions harbour widespread genomic potential for mediating particulate organic matter export. The results substantially enhance our understanding of the role played by microorganisms in regulating particulate organic matter export in suspended and sinking marine fractions in the Southern Ocean.