Black Sea hydroclimate and coupled hydrology was strongly controlled by high-latitude glacial climate dynamics

• Published in: Communications Earth & Environment
• Main Authors: Wegwerth, Antje, Plessen, Birgit, Kleinhanns, Ilka C., Arz, Helge W., Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Marine Geology, Rostock, Germany, Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Section Climate Dynamics and Landscape Evolution, Potsdam, Germany, Isotope Geochemistry, Department of Earth Sciences, University of Tübingen, Tübingen, Germany
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Publishing Group UK 2021
• Subjects: ddc:551; paleohydrology; palaeoclimate; Black Sea; Archangelsky Ridge; isotope geochemistry; Dansgaard-Oeschger cycles; Ice Sheet; North Atlantic
• Online Access: https://doi.org/10.1038/s43247-021-00129-3; http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/11089

Abstract The Black Sea experienced pronounced millennial-scale changes in temperature and rainfall during the last glacial coinciding with Dansgaard-Oeschger cycles. However, little is known regarding the amount and sources of freshwater reaching this inland basin. Here, we present detailed ostracod δ 18 O data from the glacial Black Sea showing subdued Dansgaard-Oeschger cyclicity and four prominent longer-term saw-tooth shaped Bond-like cycles. We propose that the δ 18 Oostracods signature primarily reflects changes in the atmospheric circulation in response to the waxing and waning Eurasian Ice Sheet. The millennial-scale ice sheet variations likely resulted not only in latitudinal migrations of atmospheric frontal systems but also in shifts of dominant moisture sources for the Black Sea. Heavier isotopic precipitation arrived from the North Atlantic-Mediterranean realm during the warmer interstadials and lighter isotopic precipitation from the Eurasian continental interior during the colder stadials. The subdued Dansgaard-Oeschger variability likely reflects an integrated precipitation signal additionally affected by the long mixing times of the large Black Sea volume up to 1,500 years as suggested from hydrologic-isotope-balance modelling. Moisture sources to the Black Sea changed in response to atmospheric frontal displacements driven by Eurasian Ice Sheet dynamics during the last glacial period, according to analyses of ostracod oxygen and strontium isotope data from Black Sea sediments. Deutsche Forschungsgemeinschaft (German Research Foundation) https://doi.org/10.13039/501100001659 https://doi.org/10.5281/zenodo.4545579