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

• Published in: Nature Communications
• Main Authors: Weber, M.E., Bailey, I., Hemming, S.R., Martos, Y.M., Reilly, B.T., Ronge, T.A., Brachfeld, S., Williams, T., Raymo, M., Belt, M., Smik, L., vogel, H., Peck, V., Armbrecht, L., Cage, A., Cardillo, F.G., Du, Z., Fauth, G., Fogwill, C.J., García-García, Margarita
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2022
• Subjects: Medio Marino; Centro Oceanográfico de Cádiz; carbon cycle; antarctic zone; ice ages; carbon; pleistocene; Antarctic; Southern Ocean; The Antarctic; Patagonia; Weddell; Antarc*; Sea ice
• Online Access: http://hdl.handle.net/10508/15910; http://hdl.handle.net/10261/318728; https://doi.org/10.1038/s41467-022-29642-5

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 CO2 levels. SI