Evidence for enhanced North Pacific Intermediate Water in the Bering Sea during extreme glacials over the past 1.2 Ma from records of stable isotopes analyzed at IODP Site 323-U1342 Holes A, C, and D

• Main Authors: Knudson, Karla P, Ravelo, Ana Christina
• Format: Dataset
• Language: English
• Published: PANGAEA 2017
• Subjects: Integrated Ocean Drilling Program / International Ocean Discovery Program; IODP; Bering Sea; Bering Strait; Pacific; North Atlantic Deep Water; North Atlantic
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.876180; https://doi.org/10.1594/PANGAEA.876180

The Bering Strait provides a shallow connection that allows freshwater to flow from the North Pacific into the North Atlantic, but this passage was closed during past glacials when sea level was at least 50 m lower than at present. Climate models investigating Bering Strait closure predict that this mechanism increases the salinity in the North Atlantic and reduces the salinity in the North Pacific, inducing a Pacific-Atlantic seesaw in meridional overturning circulation and poleward heat flux. However, the Pacific circulation response to Bering Strait closure, and thus the seesaw theory, has not been tested by long paleoceanographic records. We present long records of foraminiferal d18O and d13C from Integrated Ocean Drilling Program Site 323-U1342 in the Bering Sea, which provide the first evidence of enhanced North Pacific Intermediate Water when the Bering Strait was closed during each of the extreme glacials of the last 1.2 Myr. These results suggest that orbital-scale variations in North Pacific Intermediate Water are coherent and in phase with variations in upper North Atlantic Deep Water but are unrelated to changes in lower North Atlantic Deep Water. Together, these results provide evidence for systematic, orbital-scale variability in North Pacific Ocean circulation and may challenge the idea of an orbital-scale Pacific-Atlantic seesaw.