气候变化领域集成服务门户(CCPortal): Evolution of Antarctic Intermediate Water during the Plio-Pleistocene and implications for global climate: Evidence from the South Atlantic

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DOI	10.1016/j.quascirev.2019.105945
	Evolution of Antarctic Intermediate Water during the Plio-Pleistocene and implications for global climate: Evidence from the South Atlantic
	Karas C.; Goldstein S.L.; deMenocal P.B.
发表日期	2019
ISSN	0277-3791
卷号	223
英文摘要	Formed in the Southern Ocean, Antarctic Intermediate Water (AAIW) plays a fundamental role in the modern climate system as an important sink for atmospheric CO2, and as a mid-depth conduit supplying nutrient-rich waters to subtropical and tropical upwelling regions. During the transition from warm Pliocene ‘greenhouse’ conditions to Pleistocene ‘icehouse’ conditions around 3 Ma, model simulations suggest dramatic circulation changes in the Southern Ocean AAIW formation region due to cooling and expanded sea ice cover around Antarctica. However, the history and properties of AAIW over this time period are still poorly understood. Here, we trace AAIW source water provenance, temperature, and salinity changes over the last 4 Myr using Nd isotopes of Fe-Mn-oxyhydroxide encrusted foraminifera, benthic foraminiferal Mg/Ca, and stable isotopes from southwest Atlantic DSDP Site 516. Our results show that modern AAIW properties emerged gradually over the last 3 Myr, as evidenced by gradual cooling (6 °C) and freshening of intermediate waters. Over this same interval, εNd-values decrease and diverge away from those of Pacific-sourced waters and converge on values of present-day Circumpolar Deep Water (CDW). These observations are in accordance with model simulations indicating increased deep vertical mixing at the Polar Front associated with sea ice extension. These modified AAIW source waters penetrated increasingly northward into the Atlantic at intermediate depths, enhancing nutrient supply and contributing to surface cooling along subtropical coastal upwelling sites. These circulation changes may have facilitated ocean CO2 storage, providing a positive feedback amplifying global cooling and intensification of Northern Hemisphere Glaciation. © 2019 Elsevier Ltd
语种	英语
scopus关键词	Carbon dioxide; Glacial geology; Iron compounds; Isotopes; Manganese compounds; Nutrients; Sea ice; Tropics; Antarctic intermediate waters; Circulation changes; Coastal upwelling; Intermediate depths; Intermediate waters; Northern hemisphere glaciations; Nutrient-rich water; Southwest Atlantic; Manganese removal (water treatment); Antarctic Intermediate Water; benthic foraminifera; carbon dioxide; cooling; Deep Sea Drilling Project; foraminifera; glaciation; global climate; ice cover; Northern Hemisphere; Pleistocene; Pliocene; Pliocene-Pleistocene boundary; sea ice; upwelling; vertical mixing; Atlantic Ocean; Atlantic Ocean (South); Southern Ocean; Foraminifera
来源期刊	Quaternary Science Reviews
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/151728
作者单位	Lamont Doherty Earth Observatory of Columbia University, Palisades, NY 10964, United States; Instituto de Geografía, Pontificia Universidad Católica de Chile, Santiago, Chile; Millennium Nucleus Paleoclimate, University of Chile, Santiago, Chile; Department of Earth and Environmental Sciences, Columbia University, Palisades, NY 10964, United States
推荐引用方式 GB/T 7714	Karas C.,Goldstein S.L.,deMenocal P.B.. Evolution of Antarctic Intermediate Water during the Plio-Pleistocene and implications for global climate: Evidence from the South Atlantic[J],2019,223.
APA	Karas C.,Goldstein S.L.,&deMenocal P.B..(2019).Evolution of Antarctic Intermediate Water during the Plio-Pleistocene and implications for global climate: Evidence from the South Atlantic.Quaternary Science Reviews,223.
MLA	Karas C.,et al."Evolution of Antarctic Intermediate Water during the Plio-Pleistocene and implications for global climate: Evidence from the South Atlantic".Quaternary Science Reviews 223(2019).