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Status: Bibliographieeintrag

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Verfasst von:Thöle, Lena Mareike [VerfasserIn]   i
 Amsler, Helen Eri [VerfasserIn]   i
 Lippold, Jörg [VerfasserIn]   i
Titel:Glacial-interglacial dust and export production records from the Southern Indian Ocean
Verf.angabe:Lena M. Thöle, H. Eri Amsler, Simone Moretti, Alexandra Auderset, James Gilgannon, Jörg Lippold, Hendrik Vogel, Xavier Crosta, Alain Mazaud, Elisabeth Michel, Alfredo Martínez-García, Samuel L. Jaccard
E-Jahr:2019
Jahr:12 August 2019
Umfang:14 S.
Fussnoten:Gesehen am 21.08.2019
Titel Quelle:Enthalten in: Earth and planetary science letters
Ort Quelle:Amsterdam [u.a.] : Elsevier, 1966
Jahr Quelle:2019
Band/Heft Quelle:525(2019) Artikel-Nummer 115716, 14 Seiten
ISSN Quelle:1385-013X
Abstract:We present 230Th-normalized dust and export production fluxes for two contrasted marine sediment cores spanning the Antarctic Polar Front, close to the Kerguelen Plateau in the Southern Indian Ocean, covering the last glacial cycle. We report glacial lithogenic fluxes comparable to the South Atlantic and higher than in the South Pacific sectors of the Southern Ocean. Structural and temporal discrepancies with dust reconstructions from Antarctic ice cores and the Atlantic and Pacific sectors of the Subantarctic Zone (SAZ) point towards Southern Africa and/or the Kerguelen Plateau as an additional source of lithogenic material to the Southern Indian Ocean during the last ice age. In the SAZ, export production proxies respond to iron (Fe) fertilization with total organic carbon (TOC) fluxes as high as those previously reported from the Atlantic sector of the Southern Ocean. However, the correlation between export production and dust proxies is weaker than in the other sectors, and shows a muted response of export production during peak glacials. We hypothesize that this muted response may be related to macronutrient (co-)limitation imposed on phytoplankton growth possibly induced by a northward displacement of wind-driven upwelling and/or the polar frontal system during peak glacials. The Antarctic Zone (AZ) record depicts the typical pattern of enhanced export production during interglacials and comparatively low productivity during glacials suggesting a decrease in the supply of macronutrients to the AZ surface during ice ages compared to warm periods, as previously proposed. However, a muted response of opal fluxes during marine isotope stage (MIS) 5e argues for a southward migration of the frontal system during warmer MIS 5e, possibly causing silicic acid (co-)limitation at this site. These results illustrate the important role of Fe fertilization and changes in wind-driven upwelling intensities in modulating the strength and efficiency of the biological carbon pump in the Southern Ocean, but also highlight the potential role of frontal movements in explaining export production variability at sites located close to the Antarctic Circumpolar Current (ACC) fronts. Overall, our new datasets provide new insights on the regional differences in dust and export production patterns that need to be considered in order to evaluate the efficiency of carbon sequestration in the different sectors of the Southern Ocean during ice ages.
DOI:doi:10.1016/j.epsl.2019.115716
URL:Bitte beachten Sie: Dies ist ein Bibliographieeintrag. Ein Volltextzugriff für Mitglieder der Universität besteht hier nur, falls für die entsprechende Zeitschrift/den entsprechenden Sammelband ein Abonnement besteht oder es sich um einen OpenAccess-Titel handelt.

Volltext ; Verlag ; Resolving-System: https://doi.org/10.1016/j.epsl.2019.115716
 Volltext: http://www.sciencedirect.com/science/article/pii/S0012821X19304029
 DOI: https://doi.org/10.1016/j.epsl.2019.115716
Datenträger:Online-Ressource
Sprache:eng
Sach-SW:Antarctic Zone
 glacial-interglacial changes
 iron fertilization
 Southern Ocean
 Subantarctic Zone
K10plus-PPN:1671735986
Verknüpfungen:→ Zeitschrift

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