Antiphased dust deposition and productivity in the Antarctic Zone over 1.5 million years

• Published in: Nature Communications
• Main Authors: Weber, ME, Bailey, I, Hemming, SR, Martos, YM, Reilly, BT, Ronge, TA, Brachfeld, S, Williams, T, Raymo, M, Belt, ST, Smik, L, Vogel, H, Peck, VL, Armbrecht, L, Cage, A, Cardillo, FG, Du, Z, Fauth, G, Fogwill, CJ, Garcia, M, Garnsworthy, M, Gluder, A, Guitard, M, Gutjahr, M, Hernandez-Almeida, I, Hoem, FS, Hwang, JH, Iizuka, M, Kato, Y, Kenlee, B, OConnell, S, Perez, LF, Seki, O, Stevens, L, Tauxe, L, Tripathi, S, Warnock, J, Zheng, X
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Publishing Group 2022
• Subjects: Earth Sciences; Physical geography and environmental geoscience; Palaeoclimatology; Antarctic; Patagonia; Southern Ocean; The Antarctic; Weddell; Antarc*; Sea ice
• Online Access: https://doi.org/10.1038/s41467-022-29642-5; http://www.ncbi.nlm.nih.gov/pubmed/35440628; http://ecite.utas.edu.au/150407

The Southern Ocean paleoceanography provides key insights into how iron fertilization and oceanic productivity developed through Pleistocene ice-ages and their role in influencing the carbon cycle. We report a high-resolution record of dust deposition and ocean productivity for the Antarctic Zone, close to the main dust source, Patagonia. Our deep-ocean records cover the last 1.5 Ma, thus doubling that from Antarctic ice-cores. We find a 5 to 15-fold increase in dust deposition during glacials and a 2 to 5-fold increase in biogenic silica deposition, reflecting higher ocean productivity during interglacials. This antiphasing persisted throughout the last 25 glacial cycles. Dust deposition became more pronounced across the Mid-Pleistocene Transition (MPT) in the Southern Hemisphere, with an abrupt shift suggesting more severe glaciations since ~0.9 Ma. Productivity was intermediate pre-MPT, lowest during the MPT and highest since 0.4 Ma. Generally, glacials experienced extended sea-ice cover, reduced bottom-water export and Weddell Gyre dynamics, which helped lower atmospheric CO 2 levels.