Diatom-bound nitrogen isotope and opal flux records over the Holocene period in Southern Ocean sediment cores MD12-3396, MD11-3353 and PS75/072-4 ...

• Main Authors: Studer, Anja S, Sigman, Daniel M, Martínez‐García, Alfredo, Thöle, Lena, Michel, Elisabeth, Jaccard, Samuel L, Lippold, Jörg, Mazaud, Alain, Wang, Xingchen, Robinson, Laura F, Adkins, Jess F, Haug, Gerald H
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 2018
• Subjects: North Atlantic Deep Water; North Atlantic; Southern Ocean
• Online Access: https://dx.doi.org/10.1594/pangaea.891436; https://doi.pangaea.de/10.1594/PANGAEA.891436

A rise in the atmospheric CO2 concentration of ~20 parts per million over the course of the Holocene has long been recognized as exceptional among interglacials and is in need of explanation. Previous hypotheses involved natural or anthropogenic changes in terrestrial biomass, carbonate compensation in response to deglacial outgassing of oceanic CO2, and enhanced shallow water carbonate deposition. Here, we compile new and previously published fossil-bound nitrogen isotope records from the Southern Ocean that indicate a rise in surface nitrate concentration through the Holocene. When coupled with increasing or constant export production, these data suggest an acceleration of nitrate supply to the Southern Ocean surface from underlying deep water. This change would have weakened the ocean's biological pump that stores CO2 in the ocean interior, possibly explaining the Holocene atmospheric CO2 rise. Over the Holocene, the circum-North Atlantic region cooled, and the formation of North Atlantic Deep Water ... : Supplement to: Studer, Anja S; Sigman, Daniel M; Martínez‐García, Alfredo; Thöle, Lena; Michel, Elisabeth; Jaccard, Samuel L; Lippold, Jörg; Mazaud, Alain; Wang, Xingchen; Robinson, Laura F; Adkins, Jess F; Haug, Gerald H (2018): Increased nutrient supply to the Southern Ocean during the Holocene and its implications for the pre-industrial atmospheric CO2 rise. Nature Geoscience ...