EGU22-9067, updated on 28 Mar 2022
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

AmazonFACE – Assessing the response of Amazon rainforest functioning to rising atmospheric CO2 concentration

Anja Rammig1, David Lapola2, and the AmazonFACE team*
Anja Rammig and David Lapola and the AmazonFACE team
  • 1Technische Universität München, TUM School of Life Sciences, Freising, Germany (
  • 2University of Campinas, Center for Meteorological and Climatic Research Applied to Agriculture, Campinas, Brazil (
  • *A full list of authors appears at the end of the abstract

The rapid rise in atmospheric CO2 concentration over the past century is unprecedented. It has unambiguously influenced Earth’s climate system and terrestrial ecosystems. Plant responses to rising atmospheric CO2 concentrations are thought to have induced an increase in biomass and thus, increased the carbon sink in forests worldwide. Rising CO2 directly stimulates photosynthesis (the so-called CO2-fertilization effect) and tends to reduce stomatal conductance, leading to enhanced water-use efficiency, which may provide an important buffering effect for plants during adverse climate conditions. For these reasons, current global climate simulations consistently predict that tropical forests will continue to sequester more carbon in aboveground biomass, while several lines of evidence point towards a decreasing carbon sink strength of the Amazon rainforest in the coming decades, potentially driven by nutrient limitation, droughts or other factors. Mechanistically modelling the effects of rising CO2 in the Amazon rainforest are hindered by a lack of direct observations from ecosystem scale CO2 experiments. To address these critical issues, we have been developing a free-air CO2 enrichment (FACE) experiment in an old-growth, highly diverse, tropical forest in the Brazilian Amazon and we present our main hypotheses that underpin the AmazonFACE experiment.  We focus on possible effects of rising CO2 on carbon uptake and allocation, phosphorus cycling, water-use and plant-herbivore interactions, and discuss relevant ecophysiological processes, which need to be implemented in dynamic vegetation models to estimate future changes of the Amazon carbon sink. We also report recent results from the open-top chamber experiments on understorey saplings under rising CO2 and phosphorus fertilization, recently conducted at the AmazonFACE site. We give an overview over phosphorus uptake strategies and potential modelling approaches.

AmazonFACE team:

From the National Institute of Amazonian Research, Manaus, Brazil: Lugli, Laynara F.; Bachega, Luciana R.; Martins, Nathielly P.; Leite, Pamela; Pereira, Ana Caroline, M.; Pereira, Iokanam; Guedes, Alacimar; Garcia, Sabrina; Santana, Flavia; Aleixo, Izabela; Portela, Bruno T. T.; Damasceno, Amanda; Ushida, Gabriela; Ferrer, Vanessa; Souza, Cassio; Moraes, Anna C. M.; Quesada, Carlos A.; From the University of Vienna, Austria: Fuchslueger, Lucia; From Florida International University, Miami, United States: Valverde-Barrantes, Oscar; From University of Exeter, UK: Hartley, Iain P.; From Technical University of Munich, Freising, Germany: Grams Thorsten, Reichert Tatiana; From Max-Planck-Institute for Biogeochemistry, Jena, Germany: Katrin Fleischer; From University of Tennessee, United States: Norby, Richard; From International Institute for Applied Systems Analysis, Laxemburg, Austria: Hofhansl, Florian; From Wageningen University, Netherlands: Kruijt, Bart; From University of Bristol, UK: DeKauwe, Martin

How to cite: Rammig, A. and Lapola, D. and the AmazonFACE team: AmazonFACE – Assessing the response of Amazon rainforest functioning to rising atmospheric CO2 concentration, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9067,, 2022.