气候变化领域集成服务门户(CCPortal): Water mass gradients of the mid-depth Southwest Atlantic during the past 25,000 years

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DOI	10.1016/j.epsl.2019.115963
	Water mass gradients of the mid-depth Southwest Atlantic during the past 25,000 years
	Pöppelmeier F.; Gutjahr M.; Blaser P.; Oppo D.W.; Jaccard S.L.; Regelous M.; Huang K.-F.; Süfke F.; Lippold J.
发表日期	2020
ISSN	0012821X
卷号	531
英文摘要	Antarctic Intermediate Water (AAIW) plays a central role in the Atlantic Meridional Overturning Circulation (AMOC) as the return flow of Northern Sourced Water (NSW) and is therefore of significant importance for the global climate. Past variations of the boundary between AAIW and NSW have been extensively investigated, yet available results documenting the prevailing depth of this boundary and the southern extent of NSW during the last ice age remain ambiguous. Here, we present five new timeseries focusing on the authigenic neodymium isotope signal in sediment cores retrieved from the Southwest Atlantic covering the past 25,000 years. The sites are situated along the southern Brazil Margin and form a bathymetric transect ranging between 1000 and 3000 m water depth, encompassing the modern water mass boundaries of AAIW and NSW and therefore allow their reconstruction since the Last Glacial Maximum (LGM). The new Nd isotope records show little change between the LGM and early deglaciation as well as relatively homogeneous values over the full depth range of the cores during these times. These results strongly contrast with epibenthic foraminiferal stable carbon isotope records (δ13C) from the same sites which exhibit highest glacial values at mid-depths, presumably related to NSW mixing into southern sourced water. We propose that the discrepancy between these two independent water mass proxies is partly related to changes in Nd end member properties of glacial AAIW. The combination of elevated glacial dust fluxes and, as a result, sustained export productivity caused high sinking particle flux in the western South Atlantic, where AAIW is forming. Higher particle flux would have increased the removal (scavenging) of Nd from shallow waters thus reducing the Nd concentration and overprinting the isotopic signature of the glacial AAIW end member. Only under consideration of changes in Nd end member properties along with non-conservative processes such as remineralization of organic matter influencing past seawater δ13C can we reconcile the water mass reconstructions from both proxies. © 2019 Elsevier B.V.
关键词	AMOC Antarctic Intermediate Water Last Glacial Maximum neodymium isotopes Southwest Atlantic
英文关键词	Glacial geology; Isotopes; Neodymium; AMOC; Antarctic intermediate waters; Last Glacial Maximum; Neodymium isotopes; Southwest Atlantic; Oceanography; Antarctic Intermediate Water; Last Glacial Maximum; meridional circulation; neodymium isotope; overturn; sediment core; time series analysis; water mass; Atlantic Ocean; Atlantic Ocean (Southwest)
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202836
作者单位	Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany; GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany; Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA, United States; Institute of Geological Sciences, Oeschger Center for Climate Change Research, University of Bern, Bern, Switzerland; GeoZentrum Nordbayern, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany; Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan
推荐引用方式 GB/T 7714	Pöppelmeier F.,Gutjahr M.,Blaser P.,et al. Water mass gradients of the mid-depth Southwest Atlantic during the past 25,000 years[J],2020,531.
APA	Pöppelmeier F..,Gutjahr M..,Blaser P..,Oppo D.W..,Jaccard S.L..,...&Lippold J..(2020).Water mass gradients of the mid-depth Southwest Atlantic during the past 25,000 years.Earth and Planetary Science Letters,531.
MLA	Pöppelmeier F.,et al."Water mass gradients of the mid-depth Southwest Atlantic during the past 25,000 years".Earth and Planetary Science Letters 531(2020).