Changes in the composition of marine and sea-ice diatoms derived from sedimentary ancient DNA of the eastern Fram Strait over the past 30 000 years
H. H. Zimmermann,
K. R. Stoof-Leichsenring,
S. Kruse,
J. Müller,
J. Müller,
J. Müller,
R. Stein,
R. Stein,
R. Stein,
R. Tiedemann,
U. Herzschuh,
U. Herzschuh,
U. Herzschuh
Affiliations
H. H. Zimmermann
Polar Terrestrial Environmental Systems, Alfred Wegener Institute
Helmholtz Centre for Polar and Marine Research, 14473 Potsdam, Germany
K. R. Stoof-Leichsenring
Polar Terrestrial Environmental Systems, Alfred Wegener Institute
Helmholtz Centre for Polar and Marine Research, 14473 Potsdam, Germany
S. Kruse
Polar Terrestrial Environmental Systems, Alfred Wegener Institute
Helmholtz Centre for Polar and Marine Research, 14473 Potsdam, Germany
J. Müller
Marine Geology, Alfred Wegener Institute Helmholtz Centre for Polar
and Marine Research, 27568 Bremerhaven, Germany
J. Müller
MARUM, University of Bremen, 28359 Bremen, Germany
J. Müller
Faculty of Geosciences, University of Bremen, 28334 Bremen, Germany
R. Stein
Marine Geology, Alfred Wegener Institute Helmholtz Centre for Polar
and Marine Research, 27568 Bremerhaven, Germany
R. Stein
MARUM, University of Bremen, 28359 Bremen, Germany
R. Stein
Faculty of Geosciences, University of Bremen, 28334 Bremen, Germany
R. Tiedemann
Marine Geology, Alfred Wegener Institute Helmholtz Centre for Polar
and Marine Research, 27568 Bremerhaven, Germany
U. Herzschuh
Polar Terrestrial Environmental Systems, Alfred Wegener Institute
Helmholtz Centre for Polar and Marine Research, 14473 Potsdam, Germany
U. Herzschuh
Institute of Biochemistry and Biology, University of Potsdam, 14476
Potsdam, Germany
U. Herzschuh
Institute of Environmental Sciences and Geography, University of
Potsdam, 14476 Potsdam, Germany
The Fram Strait is an area with a relatively low and irregular distribution of diatom microfossils in surface sediments, and thus microfossil records are scarce, rarely exceed the Holocene, and contain sparse information about past richness and taxonomic composition. These attributes make the Fram Strait an ideal study site to test the utility of sedimentary ancient DNA (sedaDNA) metabarcoding. Amplifying a short, partial rbcL marker from samples of sediment core MSM05/5-712-2 resulted in 95.7 % of our sequences being assigned to diatoms across 18 different families, with 38.6 % of them being resolved to species and 25.8 % to genus level. Independent replicates show a high similarity of PCR products, especially in the oldest samples. Diatom sedaDNA richness is highest in the Late Weichselian and lowest in Mid- and Late Holocene samples. Taxonomic composition is dominated by cold-water and sea-ice-associated diatoms and suggests several reorganisations – after the Last Glacial Maximum, after the Younger Dryas, and after the Early and after the Mid-Holocene. Different sequences assigned to, amongst others, Chaetoceros socialis indicate the detectability of intra-specific diversity using sedaDNA. We detect no clear pattern between our diatom sedaDNA record and the previously published IP25 record of this core, although proportions of pennate diatoms increase with higher IP25 concentrations and proportions of Nitzschia cf. frigida exceeding 2 % of the assemblage point towards past sea-ice presence.
