Concentration, accumulation rates, Th fluxes, focusing factors, and productivity proxies on core PS97/093-2 over the past 400,000 years ...

• Main Authors: Toyos, Maria H, Winckler, Gisela, Arz, Helge Wolfgang, Lembke-Jene, Lester, Lange, Carina Beatriz, Kuhn, Gerhard, Lamy, Frank
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 2021
• Subjects: Drake Passage; glacial-interglacial changes; iron fertilization; Mass accumulation rates; paleoproductivity; Southern Ocean; Subantarctic zone; thorium normalization; Pacific; Ice Sheet
• Online Access: https://dx.doi.org/10.1594/pangaea.934588; https://doi.pangaea.de/10.1594/PANGAEA.934588

Changes in Southern Ocean export production have broad biogeochemical and climatic implications. Specifically, iron fertilization likely increased subantarctic nutrient utilization and enhanced the efficiency of the biological pump during glacials. However, past export production in the subantarctic Southeast Pacific is poorly documented, and its connection to Fe fertilization, potentially related to Patagonian Ice Sheet dynamics is unknown. We report biological productivity changes over the past 400 ka, based on a combination of 230Thxs-normalized and stratigraphy-based mass accumulation rates of biogenic barium, organic carbon, biogenic opal, and calcium carbonate as indicators of paleo-export production in a sediment core upstream of the Drake Passage (57.5º S; 70.3º W). In addition, we use fluxes of iron and lithogenic material as proxies for terrigenous input, and thus potential micronutrient supply. Stratigraphy-based mass accumulation rates are strongly influenced by bottom-current dynamics, which ...