Deep Equatorial Pacific Ocean Oxygenation and Atmospheric CO2 Over The Last Ice Age

• Published in: Scientific Reports
• Main Authors: Marcantonio, Franco, Hostak, Ryan, Hertzberg, Jennifer E., Schmidt, Matthew W.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media LLC 2020
• Subjects: Multidisciplinary; Pacific; Southern Ocean
• Online Access: http://dx.doi.org/10.1038/s41598-020-63628-x; http://www.nature.com/articles/s41598-020-63628-x.pdf; http://www.nature.com/articles/s41598-020-63628-x

Abstract Ventilation of carbon stored in the deep ocean is thought to play an important role in atmospheric CO 2 increases associated with Pleistocene deglaciations. The presence of this respired carbon has been recorded by an array of paleoceanographic proxies from various locations across the global ocean. Here we present a new sediment core from the Eastern Equatorial Pacific (EEP) Ocean spanning the last 180,000 years and reconstruct high-resolution 230 Th-derived fluxes of 232 Th and excess barium, along with redox-sensitive uranium concentrations to examine past variations in dust delivery, export productivity, and bottom-water oxygenation, respectively. Our bottom-water oxygenation record is compared to other similar high-resolution records from across the Pacific and in the Southern Ocean. We suggest that the deep Pacific is a site of respired carbon storage associated with periods of decreased global atmospheric CO 2 concentration during the LGM, confirming the conclusions from a wealth of previous studies. However, our study is the first to show a similar relationship beyond the last glacial, extending to at least 70,000 years.