Marine ecosystem shifts with deglacial sea-ice loss inferred from ancient DNA shotgun sequencing
Heike Zimmermann, Kathleen R. Stoof‐Leichsenring, Viktor Dinkel, Lars Harms, Luise Schulte, Marc‐Thorsten Hütt, Dirk Nürnberg, Ralf Tiedemann, Ulrike Herzschuh
Abstract
Sea ice is a key factor for the functioning and services provided by polar marine ecosystems. However, ecosystem responses to sea-ice loss are largely unknown because time-series data are lacking. Here, we use shotgun metagenomics of marine sedimentary ancient DNA off Kamchatka (Western Bering Sea) covering the last ~20,000 years. We traced shifts from a sea ice-adapted late-glacial ecosystem, characterized by diatoms, copepods, and codfish to an ice-free Holocene characterized by cyanobacteria, salmon, and herring. By providing information about marine ecosystem dynamics across a broad taxonomic spectrum, our data show that ancient DNA will be an important new tool in identifying long-term ecosystem responses to climate transitions for improvements of ocean and cryosphere risk assessments. We conclude that continuing sea-ice decline on the northern Bering Sea shelf might impact on carbon export and disrupt benthic food supply and could allow for a northward expansion of salmon and Pacific herring.