Dynamic land-plant carbon sources in marine sediments inferred from ancient DNA

Abstract Terrigenous organic matter in marine sediments is considered a significant long-term carbon sink, yet our knowledge regarding its source taxa is severely limited. Here, we leverage land-plant ancient DNA from six globally distributed marine sediment cores covering the Last Glacial–Holocene transition as a proxy for the share, burial rate, preservation, and composition of terrigenous organic matter. We show that the spatial and temporal plant composition as revealed by sedimentary ancient DNA records reflects mainly the vegetation dynamics of nearby continents as revealed by comparison with pollen from land archives. However, we also find indications of a global north-to-south translocation of sedimentary ancient DNA. We also find that plant sedimentary ancient DNA has a higher burial rate in samples from the Late Glacial, which is characterized by high runoff and mineral load. This study provides an approach to understanding the global linkages between the terrestrial and marine carbon cycle, highlighting the need for further research to quantify the processes of DNA preservation and dispersal in marine sediments.