Tuesday 25 October 2022 at 15:00 UTC
Speaker: Dr. Patrick Blaser from University of Lausanne, Switzerland
The oceans are a vital part of the climate system and played an integral role in modulating Quaternary glacial cycles. For an improved fundamental understanding of this role and of the ocean system it is important to get accurate information about the past sourcing of deep ocean water due to its profound impact on marine carbon storage, heat transport, and ventilation. Yet, to date deep Atlantic water mass sourcing during past glacials is still debated, and interpretations based on different proxies such as carbon and neodymium isotopes appear to be at odds.
Here, we present evidence for the existence of a Glacial North Atlantic Deep Water in the subpolar North Atlantic. We then estimate Atlantic water mass sourcing by integrating data compilations of five different proxies (stable isotopes of carbon and oxygen, neodymium isotopes, carbonate ion concentration, and radiocarbon ventilation age) from the Last Glacial Maximum and Heinrich Stadial 1 with the help of a Bayesian mixing model.
We show that a moderate expansion of southern sourced waters in combination with widespread northern sourced deep water best explain proxy observations. Changes between LGM and HS1 were dominated by changes in water mass characteristics, rather than distribution, implying that deep water formation intensity may not have changed drastically. These analyses offer new detailed insights into glacial deep Atlantic water mass sourcing and reconcile findings from studies using individual proxies.
Contact: Ning Zhao, firstname.lastname@example.org