NOAA/WDS Paleoclimatology - East China Sea, Northern Okinawa Trough Trace Element Data over the Last 400,000 Years

The carbon release from the subarctic Pacific in glacial-interglacial cycles has been mainly linked to the North Pacific Intermediate Water (NPIW) formation and associated carbon/nutrient water upwelling and biological productivity, suggesting the significant role of NPIW in the global carbon cycle. However, the causes of the past NPIW formation remain controversial. Here we report a high-resolution sediment record of NPIW evolution based on the paleo-redox changes in the Western North Pacific during the last 400 ka. Our proxy and model simulation results reveal the delayed collapse of NPIW after the glacial termination was coeval with decreased salinity of intermediate water mass in the subarctic Pacific. We attributed these salinity anomalies to the increased local net rainfall forced by delayed Northern Hemisphere warming compared with the Southern Ocean. Such atmospheric-oceanic interactions in the subarctic Pacific probably make a contribution to maintain high atmospheric CO2 concentrations through weakened intermediate-to-deep ocean stratification and reduced subsurface biological pump net efficiency, countering the return to more stratified conditions in the Southern Ocean, which should drive down atmospheric CO2 during the early interglacial.