Reply to: No freshwater-filled glacial Arctic Ocean

• Published in: Nature
• Main Authors: Geibert, Walter, Matthiessen, Jens, Wollenburg, Jutta, Stein, Ruediger
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2022
• Subjects: Arctic; Arctic Ocean; Foraminifera*; Greenland; Greenland-Scotland Ridge; Ice Shelf; Nordic Seas; North Atlantic
• Online Access: https://epic.awi.de/id/eprint/55673/; https://doi.org/10.1038/s41586-021-04090-1; https://hdl.handle.net/10013/epic.700296b1-2a08-4ef2-8fc9-b1e568d8736e

In the accompanying Comment1, Spielhagen et al. respond to our recent Article2, raising several issues concerning the perceived impossibility of a glacial freshwater ocean, focusing on the Nordic Seas and the North Atlantic south of the Greenland–Scotland ridge (GSR). They argue that no basin-wide 230Thex minima were seen in the Nordic Seas at the times proposed, and that they were due to dilution by high mass fluxes; that 10Be records closely resemble those of 230Thex, which they assume to support only the dilution hypothesis; that the reportedly continuous foraminiferal δ18O records were incompatible with freshwater under an ice shelf north of the GSR; and that no corresponding meltwater signal was seen in North Atlantic foraminiferal δ18O records south of the GSR. We highlight the circular arguments that result from the reliance on just one overstretched proxy for constraining age, temperature and salinity. Our interpretation is in line with observations and with the rapid melting during glacial terminations.