Precipitation changes over the eastern Bolivian Andes inferred from speleothem (δ18O) records for the last 1400 years

James Apaéstegui, Francisco William Cruz, Mathias Vuille, Jens Fohlmeister, Jhan Carlo Espinoza, Abdelfettah Sifeddine, Nicolas Strikis, Jean Loup Guyot, Roberto Ventura, Hai Cheng, R. Lawrence Edwards

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18 Scopus citations

Abstract

Here we present high-resolution δ18O records obtained from speleothems collected in the eastern Bolivian Andes. The stable isotope records are related to the regional- to large-scale atmospheric circulation over South America and allow interpreting changes in δ18O during the last 1400 yr as a function of changes in precipitation regimes over the southern tropical Andes. Two distinct phases with more negative δ18O values, interpreted as periods of increased convective activity over the eastern Andean Cordillera in Bolivia are observed concomitantly with periods of global climate anomalies during the last millennium, such as the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA) respectively. Changes in the Bolivian δ18O record during the LIA are apparently related to a southward displacement of the Intertropical Convergence Zone (ITCZ), which acts as a main moisture driver to intensify convection over the tropical continent. During the MCA, however, the increased convective activity observed in the Bolivian record is likely the result of a different mechanism, which implies moisture sourced mainly from the southern tropical Atlantic. This interpretation is consistent with paleoclimate records further to the north in the tropical Andes that show progressively drier conditions during this time period, indicating a more northerly position of the ITCZ. The transition period between the MCA and the LIA shows a slight tendency toward increased δ18O values, indicating weakened convective activity. Our results also reveal a non-stationary anti-phased behavior between the δ18O reconstructions from Bolivia and northeastern Brazil that confirms a continental-scale east–west teleconnection across South America during the LIA.

Original languageEnglish (US)
Pages (from-to)124-134
Number of pages11
JournalEarth and Planetary Science Letters
Volume494
DOIs
StatePublished - Jul 15 2018

Bibliographical note

Funding Information:
We thank Luis Mancini and Ana Carolina Miranda for their support during the stable isotope data acquisition at the Universidade de Brasília and Osmar Antunes for his support at the Universidade de São Paulo . We also thank Angela Ampuero, Omar Gutierrez and Jairo Valdivia for their computational support. Thanks to Augusto Auler for his support during the fieldwork. This study was undertaken as part of the PALEOTRACES project (IRD-UFF-UANTOF), SO-HYBAM and PRIMO cooperative project (CNPq-IRD), and supported by the Fundação de Amparo a Pesquisa do Estado de São Paulo, Brazil ( FAPESP grants 2011/39450394 and NASA/FAPESP through the Dimensions of Biodiversity Program grants 2012/50260-6 and 2013/50297-0 to F.W. Cruz) and also by grants 2013CB955902 , CNSF 41230524 , US NSF grant 0502535 and 3961103404 to L. Edwards and H. Cheng, and NSF grants 1303828 , 1523288 and 1743738 to M. Vuille and DFG grant FO809/4-1 to J. Fohlmeister. J. Apaéstegui and JC. Espinoza were partially funded by PNICP -Peru through the ‘ N397-PNICP-PIAP-2014 ’ contract.

Funding Information:
We thank Luis Mancini and Ana Carolina Miranda for their support during the stable isotope data acquisition at the Universidade de Brasília and Osmar Antunes for his support at the Universidade de São Paulo. We also thank Angela Ampuero, Omar Gutierrez and Jairo Valdivia for their computational support. Thanks to Augusto Auler for his support during the fieldwork. This study was undertaken as part of the PALEOTRACES project (IRD-UFF-UANTOF), SO-HYBAM and PRIMO cooperative project (CNPq-IRD), and supported by the Fundação de Amparo a Pesquisa do Estado de São Paulo, Brazil (FAPESP grants 2011/39450394 and NASA/FAPESP through the Dimensions of Biodiversity Program grants 2012/50260-6 and 2013/50297-0 to F.W. Cruz) and also by grants 2013CB955902, CNSF 41230524, US NSF grant 0502535 and 3961103404 to L. Edwards and H. Cheng, and NSF grants 1303828, 1523288 and 1743738 to M. Vuille and DFG grant FO809/4-1 to J. Fohlmeister. J. Apaéstegui and JC. Espinoza were partially funded by PNICP-Peru through the ‘N397-PNICP-PIAP-2014’ contract.

Publisher Copyright:
© 2018 Elsevier B.V.

Keywords

  • Bolivia
  • LIA
  • MCA
  • South American Monsoon
  • speleothems
  • stable isotopes

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