Baker, JCA orcid.org/0000-0002-3720-4758, Cintra, BBL, Gloor, M orcid.org/0000-0002-9384-6341 et al. (6 more authors) (2022) The changing Amazon hydrological cycle – inferences from over 200 years of tree-ring oxygen isotope data. Journal of Geophysical Research: Biogeosciences, 127 (10). e2022JG006955. ISSN 2169-8953
Abstract
Changes to the Amazon hydrological cycle have important consequences for world's largest tropical forest, and the biodiversity it contains. However, a scarcity of long-term climate data in the region makes it hard to contextualize recent observed changes in Amazon hydrology. Here, we explore to what extent tree-ring oxygen isotope (δ18OTR) chronologies can inform us about hydrological changes in the Amazon over the past two centuries. Two δ18OTR records from northern Bolivia and the Ecuadorian Andes are presented. The Ecuador record spans 1799–2012 (n = 16 trees) and the Bolivia record spans 1860–2014 (n = 32 trees), making them the longest δ18OTR records from the Amazon, and among the most highly-replicated δ18OTR records from the tropics to date. The two chronologies correlate well at interannual and decadal timescales, despite coming from sites more than 1,500 km apart. Both δ18OTR records are strongly related to interannual variation in Amazon River discharge measured at Óbidos, and accumulated upwind precipitation, suggesting a common climatic driver. In both records a strong increase in δ18OTR was observed up until approximately 1950, consistent with positive trends in the few other existing δ18O proxy records from across the Amazon. Considering all possible drivers of this long-term increase, a reduction in rainout fraction over the basin driven by rising sea surface temperatures in the North Atlantic is suggested as the most likely cause. The upward trend in δ18OTR reverses over the past 1–2 decades, consistent with the observed strengthening of the Amazon hydrological cycle since approximately 1990.
Metadata
Item Type: | Article |
---|---|
Authors/Creators: |
|
Copyright, Publisher and Additional Information: | © 2022. The Authors. This is an open access article under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits unrestricted use, distribution and reproduction in any medium, provided the original work is properly cited. |
Keywords: | palaeoclimate, proxy, tropical, water cycle, climate reconstruction, δ18O |
Dates: |
|
Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Inst for Climate & Atmos Science (ICAS) (Leeds) The University of Leeds > Faculty of Environment (Leeds) > School of Geography (Leeds) > Ecology & Global Change (Leeds) |
Funding Information: | Funder Grant number NERC (Natural Environment Research Council) NE/I021160/1 RCUK (Research Councils UK) NE/M022021/1 RCUK (Research Councils UK) NE/M02203X/1 NERC (Natural Environment Research Council) NE/S008659/1 NERC (Natural Environment Research Council) NE/K01353X/1 NERC (Natural Environment Research Council) NE/R005079/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 12 Sep 2022 11:14 |
Last Modified: | 01 Feb 2023 01:54 |
Status: | Published |
Publisher: | Wiley |
Identification Number: | 10.1029/2022JG006955 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:190840 |