Deglacial changes in the Southern Ocean carbon pool – Implications from marine Δ14C and [CO32-] records

• Main Authors: Ronge, Thomas, Tiedemann, Ralf, Lamy, Frank, Kersten, Franziska, Frische, Matthias, Fietzke, Jan, Pahnke, Katharina, Alloway, Brent V., Wacker, Lukas, Southon, John
• Format: Conference Object
• Language: unknown
• Published: 2014
• Subjects: Antarc*; Antarctica; Southern Ocean
• Online Access: https://epic.awi.de/id/eprint/36106/; https://hdl.handle.net/10013/epic.44062

Throughout the transition from the last Glacial to the current Interglacial, rising atmospheric CO2 levels were accompanied by declining atmospheric Δ14C values. A likely mechanism, influencing both components is the deglacial release of CO2, stored for millennia in the deep Ocean, to the atmosphere. Due to its long residence time within the oceans interior this CO2 rich water mass was considerably depleted in radiocarbon. Although a large number of studies address this topic, the extent, location and pathways of the glacial carbon pool are still subjects of an ongoing debate. As deep water masses are upwelled and new intermediate waters are formed around Antarctica, the Southern Ocean is a potential area for the deglacial release of stored CO2. Here we present radiocarbon and carbonate ion data from a transect of sediment cores off New Zealand that covers the major water masses in this area, from the AAIW down to the AABW. During the Glacial, our data locate a significantly 14C depleted pool in a water depth between 2000 and 4500 m. The combination of Δ14C and [CO32-] records provides new insights into the process of oceanic-atmospheric CO2 exchange in the Southern Ocean. In addition, our results yield new implications for contradicting Δ14C records from the Southern Ocean and lower latitudes.