Response of the Amazon rainforest to late Pleistocene climate variability

Autor(es)

Haeggi, Christoph ^[1] ; Chiessi, Cristiano M. ^[2] ; Merkel, Ute ^[1] ; Mulitza, Stefan ^[1] ; Prange, Matthias ^[1] ; Schulz, Michael ^[1] ; Schefuss, Enno ^[1]

Afiliação do(s) autor(es)

^[1] Univ Bremen, MARUM Ctr Marine Environm Sci, Leobener Str 8, D-28359 Bremen - Germany

^[2] Univ Sao Paulo, Sch Arts Sci & Humanities, Av Arlindo Bettio 1000, BR-03828000 Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Earth and Planetary Science Letters; v. 479, p. 50-59, DEC 1 2017.
• Citações Web of Science: 12

Resumo

Variations in Amazonian hydrology and forest cover have major consequences for the global carbon and hydrological cycles as well as for biodiversity, Yet, the climate and vegetation history of the lowland Amazon basin and its effect on biogeography remain debated due to the scarcity of suitable high resolution paleoclimate records. Here, we use the isotopic composition (delta D and delta C-13) of plant-waxes from a high-resolution marine sediment core collected offshore the Amazon River to reconstruct the climate and vegetation history of the integrated lowland Amazon basin for the period from 50,000 to 12,800 yr before present. Our results show that delta D values from the Last Glacial Maximum were more enriched than those from Marine Isotope Stage (MIS) 3 and the present-day. We interpret this trend to reflect long-term changes in precipitation and atmospheric circulation, with overall drier conditions during the Last Glacial Maximum. Our results thus suggest a dominant glacial forcing of the climate in lowland Amazonia. In addition to previously suggested thermodynamic mechanisms of precipitation change, which are directly related to temperature, we conclude that changes in atmospheric circulation are crucial to explain the temporal evolution of Amazonian rainfall variations, as demonstrated in climate model experiments. Our vegetation reconstruction based on delta C-13 values shows that the Amazon rainforest was affected by intrusions of savannah or more open vegetation types in its northern sector during Heinrich Stadials, while it was resilient to glacial drying. This suggests that biogeographic patterns in tropical South America were affected by Heinrich Stadials in addition to glacial-interglacial climate variability. (C) 2017 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 12/17517-3 - Resposta da porção oeste do Oceano Atlântico às mudanças na circulação meridional do Atlântico: variabilidade milenar a sazonal
• Beneficiário: Cristiano Mazur Chiessi
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Jovens Pesquisadores