North Atlantic forcing of Amazonian precipitation during the last ice age

Mosblech, Nicole A.S.; Bush, Mark B.; Gosling, William D.; Hodell, David; Thomas, Louise; van Calsteren, Peter; Correa-Metrio, Alexander; Valencia, Bryan G.; Curtis, Jason and van Woesik, Robert (2012). North Atlantic forcing of Amazonian precipitation during the last ice age. Nature Geoscience (In press).

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DOI (Digital Object Identifier) Link:	http://dx.doi.org/doi:10.1038/ngeo1588
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Abstract

The last glacial period was marked by multiple, abrupt reorganizations of ocean and atmosphere circulation. On thousand-year timescales, slowing of the Atlantic meridional overturning circulation was associated with cooling in the high northern latitudes, whereas strengthened circulation was linked to northern warming. In the tropics, these millennial-scale events were primarily reflected in altered patterns of precipitation. These hydrologic fluctuations induced ecological changes in the Atlantic seaboard and the high Andes, but less is known about the Amazon Basin. Here we reconstruct precipitation over Amazonian Ecuador over the past 94,000 years using a δ¹⁸O record from speleothems collected in Santiago Cave in western Amazonia. We interpret the variability of the δ¹⁸O record as changes in the source and amount of precipitation. With the exception of the period between 40,000 and 17,000 years ago, abrupt, high-frequency changes coincide with shifts in North Atlantic circulation, indicating a high-latitude influence on Amazonian precipitation over millennial timescales. On longer timescales, the record shows a relationship to precessional changes in the Earth’s orbit. In light of the lack of extreme aridity in our records, we conclude that ecosystems in western Amazonia have not experienced prolonged drying over the past 94,000 years.

Item Type:	Journal Article
Copyright Holders:	2012 Macmillan Publishers Limited
ISSN:	1752-0908
Funders:	National Science Foundation (NSF) Geography programme, NSF Graduate Research Fellowship programme, Natural Environments Research Council Isotope Geoscience support, National Geographic Society, NSF GK-12 programme
Extra Information:	URL and DOI may not work in Internet Explorer
Keywords:	North Atlantic; Amazon; precipitation; oxygen isotopes; Pleistocene; Ice Age
Academic Unit/Department:	Science > Environment, Earth and Ecosystems Science
Interdisciplinary Research Centre:	OpenSpace Research Centre (OSRC) Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)
Related URLs:	http://www.nature.com/ngeo/journal/vaop/...(Other)
Item ID:	34485
Depositing User:	William Gosling
Date Deposited:	04 Oct 2012 10:39
Last Modified:	14 Jan 2013 15:27
URI:	http://oro.open.ac.uk/id/eprint/34485

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