Antarctic Zone nutrient conditions during the last two glacial cycles

Studer, Anja S. and Sigman, Daniel M. and Martinez-Garcia, Alfredo and Benz, Verena and Winckler, Gisela and Kuhn, Gerhard and Esper, Oliver and Lamy, Frank and Jaccard, Samuel L. and Wacker, Lukas and Oleynik, Sergey and Gersonde, Rainer and Haug, Gerald H.. (2015) Antarctic Zone nutrient conditions during the last two glacial cycles. Paleoceanography, 30 (7). pp. 845-862.

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Official URL: https://edoc.unibas.ch/73046/

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In a sediment core from the Pacific sector of the Antarctic Zone (AZ) of the Southern Ocean, we report diatom-bound N isotope (delta N-15(db)) records for total recoverable diatoms and two distinct diatom assemblages (pennate and centric rich). These data indicate tight coupling between the degree of nitrate consumption and Antarctic climate across the last two glacial cycles, with delta N-15(db) (and thus the degree of nitrate consumption) increasing at each major Antarctic cooling event. Coupled with evidence from opal- and barium-based proxies for reduced export production during ice ages, the delta N-15(db) increases point to ice age reductions in the supply of deep ocean-sourced nitrate to the AZ surface. The two diatom assemblages and species abundance data indicate that the delta N-15(db) changes are not the result of changing species composition. The pennate and centric assemblage delta N-15(db) records indicate similar changes but with a significant decline in their difference during peak ice ages. A tentative seasonality-based interpretation of the centric-to-pennate delta N-15(db) difference suggests that late summer surface waters became nitrate free during the peak glacials.
Faculties and Departments:05 Faculty of Science > Departement Umweltwissenschaften > Geowissenschaften > Geochemie Stoffkreisläufe (Lehmann)
UniBasel Contributors:Studer, Anja
Item Type:Article, refereed
Article Subtype:Research Article
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:24 May 2020 17:20
Deposited On:24 May 2020 17:20

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