气候变化领域集成服务门户(CCPortal): Understanding the mechanisms behind high glacial productivity in the southern Brazilian margin

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DOI	10.5194/cp-15-943-2019
	Understanding the mechanisms behind high glacial productivity in the southern Brazilian margin
	Da Costa Portilho-Ramos R.; Pinho T.M.L.; Chiessi C.M.; Barbosa C.F.
发表日期	2019
ISSN	18149324
起始页码	943
结束页码	955
卷号	15 期号:3
英文摘要	This study explores the mechanisms behind the high glacial productivity in the southern Brazilian margin (SBM) during the last 70 kyr using planktonic foraminifera assemblage and subsurface temperature information derived using the modern analogue technique. We show that enhanced glacial productivity was driven by the synergy of two mechanisms operating in different seasons: (i) enhanced productivity in the upwelling region during short austral summer events; and (ii) the persistent presence of the Plata Plume Water (PPW) due to prolonged austral winter conditions. We suggest that the upwelling systems in the southern Brazilian margin were more productive during the last glacial period due to the enhanced Si supply for diatom production by high-Si thermocline waters preformed in the Southern Ocean. We hypothesize that orbital forcing did not have a major influence on changes in upwelling during the last glacial period. However, the more frequent northward intrusions of the Plata Plume Water were modulated by austral winter insolation at 60° S via changes in the strength of alongshore southwesterly winds. After the Last Glacial Maximum, the reduced Si content of thermocline waters decreased upwelling productivity, while lower austral winter insolation decreased the influence of the Plata Plume Water over the southern Brazilian margin, reducing regional productivity. © 2019 Author(s).
语种	英语
scopus关键词	fossil assemblage; glacial environment; Last Glacial Maximum; orbital forcing; planktonic foraminifera; plume; thermocline; upwelling; winter; Brazil; Southern Ocean; Bacillariophyta; Foraminifera
来源期刊	Climate of the Past
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/146816
作者单位	MARUM - Center for Marine Environmental Sciences, University of Bremen, Leobener Strasse, Bremen, 28359, Germany; Institute of Geosciences, University of São Paulo, Rua do Lago 562, São Paulo, CEP05508-080, Brazil; School of Arts Sciences and Humanities, University of São Paulo, Rua Arlindo Bettio 1000, São Paulo, CEP03828-000, Brazil; Departamento de Geoquímica, Universidade Federal Fluminense, Rua Outeiro São João Baptista S/N, Niterói, CEP24020-141, Brazil
推荐引用方式 GB/T 7714	Da Costa Portilho-Ramos R.,Pinho T.M.L.,Chiessi C.M.,et al. Understanding the mechanisms behind high glacial productivity in the southern Brazilian margin[J],2019,15(3).
APA	Da Costa Portilho-Ramos R.,Pinho T.M.L.,Chiessi C.M.,&Barbosa C.F..(2019).Understanding the mechanisms behind high glacial productivity in the southern Brazilian margin.Climate of the Past,15(3).
MLA	Da Costa Portilho-Ramos R.,et al."Understanding the mechanisms behind high glacial productivity in the southern Brazilian margin".Climate of the Past 15.3(2019).