Towards a Comprehensive Understanding of Changes in the Amazon Hydrological Cycle

Lead Research Organisation: University of Leeds
Department Name: Sch of Geography


Over the last decade the Amazon Basin has experienced extreme events of flooding (2009, 2012-2014) and droughts (2005, 2010). These events have had strong impacts not only on the Amazon forest, but also on its people and economy. How the climate of the Amazon will develop in the future remains uncertain however, as the accuracy of future climate model predictions for the Amazon is low, and as data on past natural climate/hydrology variability cover only a short period.

The proposed research partnership will be used to obtain a better understanding of long-term variability of past dry season length and precipitation intensity, and its climatic controls. This will be done by analyzing ring widths and oxygen isotopic ratios in tree rings from existing and new wood samples from floodplain trees in the Amazon. Ring width from floodplain trees will be used to reconstruct the length of the non-flooded phase, while we will use oxygen isotopes in tree rings (d18O) as a proxy for dry season precipitation d18O.
We will carry out sampling at two sites located in two sub-basins, the central region (Solimões River) and the northern sub-basin (Negro River) to provide a long-term perspective on the recent changes by revealing long time series of oxygen isotopes in the floodplain species Macrolobium acaciifolium, extending back more than 150-300 years. This will allow unraveling natural cycles from anthropogenic influences and thus allow us to predict what to expect for the future. Such predictions are of paramount importance to the people and economy of Brazil. If natural cycles explain the recent extreme events, one could expect a decrease again of these extremes in the near future. If the recent extremes are rather due to large-scale shifts in the climate system due to eg. warming of the sea surface temperatures globally, then we may expect more extreme event in the immediate future. By looking back for over 300 years, we will be able to unravel natural cycles from man-made warming. Within the current active NERC grant (NE/K01353X/1) we are using Earth system models to help in the interpretation of the recent changes.

An integral component of this proposed partnership is the joint organisation of an "international tree ring and isotope workshop" in Brazil at INPA. The objective of this workshop is to:
a) Gather international researchers and students working on this and similar topics,
b) Identify research needs in the field and brainstorm ideas to come up with concrete research directions for the next years,
c) Capacitate (mainly) Brazilian researchers and students in existing and new techniques and developments in the field.

Planned Impact

By the end of the project we will organise a meeting in Portuguese in Manaus during which we will invite regional government bodies (eg. Ministry of the Amazonas State for Environment and Sustainabe Development [Secretaria de Estado do Meio Ambiente e Desenvolvimento Sustentável -SDS), Minstry of Amazonas State for Science, Technology and Inovation [Secretaria de Estado de Ciencia, Tecnologia e Inovação - SECTI], Amparo Foundation for Research in the Amazonas State [Fundação de Amparo à Pesquisa do Estado do Amazonas - FAPEAM and National Water Agency (Agencia Nacional de Águas - ANA]). The purpose of this meeting is to communicate our findings to policy makers. We will specifically address the question to what degree recent extreme events are likely natural or man-made and what to expect for the future i.e., can we expect a further increase in such extremes, or will it remain equal or rather decrease? This will help mitigating the impact of future extreme events, and is highly relevant for policy makers in the region. Besides scientific publications we will also write up main outcome in a Portuguese report in accessible terms and distributed to policy makers and relevant government bodies.


10 25 50
Description We have identified that the ratio of oxygen and carbon isotopes in tree rings from Floodplain trees, register the dry season precipitation over the Amazon.
We further found that the variation of oxygen and carbon isotopes in tree rings, varies between floodplain trees and trees that are non-flooded (i.e.., terra fire trees) in the Amazon. This is most likely due to difference in the growing seasons for trees growing in floodplain forests (which only grow in the dry season) and deciduous terra firme trees which grow during the wet season.
Exploitation Route -By publication as scientific peer-reviewed article.
-Implications could be important for climate change predictions over the Amazon basin, giving better predictions for flood risks.
this has consequences for economy, agriculture, forestry, etc.
Sectors Agriculture, Food and Drink,Environment

Description Collaboration with INPA, Brazil, Manaus 
Organisation National Institute of Amazonian Research
Country Brazil 
Sector Public 
PI Contribution JOint fieldwork and research program on floodplain trees in the Amazon, application for grants and phd studentships, and paper writing and publishing.
Collaborator Contribution facilitation research program in Brazil.
Impact - publications - research material
Start Year 2011
Description Collaboration with University of Leicester 
Organisation University of Leicester
Country United Kingdom 
Sector Academic/University 
PI Contribution Delivering samples for isotope analysis, and scientific interpretation of results
Collaborator Contribution Isotope analysis for research.
Impact Insights into carbon isotope discrimination of tropical trees. Yet to be fully published.
Start Year 2010
Description Keynote talk during TRACE meeting (Tree-rings in Archaeology, Climatology and Ecology, 2019) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact I gave keynote talk to large audience at the TRACE 2019 meeting, on Tree-rings in Archaeology, Climatology and Ecology.
Title of talk : Tree ring in the tropics
Year(s) Of Engagement Activity 2019
Description Organisation of International workshop on trees isotopes and recent climate change int he Amazon basin 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact The purpose of this workshop was to train Brazilian and international PhD, masters and undergraduate students and researchers on tree ring and isotope techniques with a focus on use of these techniques to understand better the hydrological cycle of the Amazon basin. In total more than 50 students participated form Brazil, Peru, Venezuela, Argentina, Bolivia, and US, and we brought together an international team of researchers from Brazil, UK, USA, Chile, Peru, and France.
The workshops consisted of some very high quality seminars on the latest research on Amazon hydrology and recent changes, from experts in the field on tree rings in the Amazon, recent changes amazon climate and hydrology, isotopes in ecological studies speleothem studies and palaeoclimate studies.
The intended outcome was achieved by training students in tree ring and isotope techniques, use of climate analysis software and websites, and by bringing together experts from different fields working on climate change issues in the Amazon basin. The workshop received interests from the media through interviews with experts by one of the largest newschannels in Brazil , El globo.
Year(s) Of Engagement Activity 2016
Description Participation in international meeting/worksop in Sao Paulo - Paleoclimate in South America 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Patients, carers and/or patient groups
Results and Impact The activity consisted of the PIRE-CREATE Annual Meeting, conjointly functioning as project meeting for the NERC -FAPESP funded ISOAM project, and an associated field trip to the Peruaçu Caves National Park. The Meeting took place at the University of Sao Paulo (, and was be preceded by a field trip to cave sites in Peruaçu Caves National Park in the State of Minas Gerais (

The Meeting focused on paleoclimate reconstruction in South America and included participants and researchers from USA, Brazil, UK, Argentina, Mexico, Peru. It was attended by a total of ca. 30 international researchers, 15 postdoctoral students, 15 graduate students and many undergraduate students.
Year(s) Of Engagement Activity 2019