Large emissions from floodplain trees close the Amazon methane budget

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Wetlands are the largest global source of atmospheric methane (CH4)1, a potent greenhouse gas. However, methane emission inventories from the Amazon floodplain2,3, the largest natural geographic source of CH4 in the tropics, consistently underestimate the atmospheric burden of CH4 determined via remote sensing and inversion modelling4,5, pointing to a major gap in our understanding of the contribution of these ecosystems to CH4 emissions. Here we report CH4 fluxes from the stems of 2,357 individual Amazonian floodplain trees from 13 locations across the central Amazon basin. We find that escape of soil gas through wetland trees is the dominant source of regional CH4 emissions. Methane fluxes from Amazon tree stems were up to 200 times larger than emissions reported for temperate wet forests6 and tropical peat swamp forests7, representing the largest non-ebullitive wetland fluxes observed. Emissions from trees had an average stable carbon isotope value (δ13C) of −66.2 ± 6.4 per mil, consistent with a soil biogenic origin. We estimate that floodplain trees emit 15.1 ± 1.8 to 21.2 ± 2.5 teragrams of CH4 a year, in addition to the 20.5 ± 5.3 teragrams a year emitted regionally from other sources. Furthermore, we provide a ‘top-down’ regional estimate of CH4 emissions of 42.7 ± 5.6 teragrams of CH4 a year for the Amazon basin, based on regular vertical lower-troposphere CH4 profiles covering the period 2010–2013. We find close agreement between our ‘top-down’ and combined ‘bottom-up’ estimates, indicating that large CH4 emissions from trees adapted to permanent or seasonal inundation can account for the emission source that is required to close the Amazon CH4 budget. Our findings demonstrate the importance of tree stem surfaces in mediating approximately half of all wetland CH4 emissions in the Amazon floodplain, a region that represents up to one-third of the global wetland CH4 source when trees are combined with other emission sources.

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Change history

  • Corrected online 13 December 2017

    Please see accompanying Erratum (http://doi.org/10.1038/nature25191). In this Letter, author ‘Humberto Ribeiro’ has been corrected to ‘Humberto Marotta’, and the Acknowledgements and Author Contributions have been corrected accordingly.


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The bottom-up measurement study was funded by grants from the following bodies: UK Natural Environment Research Council to V.G. (Principal Investigator, grant NE/J010928/1) and E.R.C.H. (co-investigator, NE/J009032/1); several CNPq (Brazil National Council of Research and Development) and FAPERJ (Science Foundation from the State of Rio de Janeiro) grants to A.E.-P.; Swedish Research Council, VR (grant 2012-00048) to D.B.; and the Swedish-Brazilian collaboration STINT/CAPES to D.B. and A.E.-P. (grant 2012-2085). Atmospheric CH4 vertical profile measurements were funded by the following agencies: NERC consortium AMAZONICA, which is led by E.G. (grant NE/F005806/1) and includes L.V.G. and J.B.M.; FAPESP (State of Sao Paulo Science Foundation) via the Carbon Tracker project and FAPESP-NERC via the ACO project (grants 08/58120-3, 11/51841-0); the EU via the 7th-Framework Programme project GEOCARBON (grant 283080); and CNPq (grant 403241/2012-3, awarded to L.V.G.). NASA, NOAA, IPEN and INPE contributed to the construction and maintenance of the GHG laboratory in Brazil. We also acknowledge support from the FAPESP-NERC ACO project for a workshop that brought bottom-up and top-down data together. V.G. and E.G. thank the NERC consortium MOYA (grant NE/N015606/1) and D.B. thanks the Swedish Research Council (VR) for salary contributions. V.G. and S.R.P. acknowledge support from the AXA Research Fund. We thank T. Silva for assistance with tree species identification and A. Breves, E. Cristina, F. M. Silva, J. Valle, J. P. Felizardo, L. Rodrigues, L. Valladares, P. Souto, R. Pollery and V. Figueiredo for field work assistance. We thank A. Dwarakanath for data analysis and P. Monaghan and A. McAleer for performing δ13C-CH4 analyses.

Author information

Author notes

    • Sunitha R. Pangala

    Present address: Lancaster Environment Centre, Lancaster University, Bailrigg, Lancaster LA1 4YQ, UK.


  1. School of Environment, Earth and Ecosystem Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK

    • Sunitha R. Pangala
    •  & Vincent Gauci
  2. Department of Thematic Studies, Environmental Change, Linköping University, Linköping SE-581 83, Sweden

    • Alex Enrich-Prast
    •  & David Bastviken
  3. Department of Botany, Institute of Biology, University Federal of Rio de Janeiro, Rio de Janeiro, Brazil

    • Alex Enrich-Prast
    • , Roberta Bittencourt Peixoto
    • , Luana Silva Braucks Calazans
    •  & Cassia Mônica Sakuragui
  4. Instituto de Pesquisas Energéticas e Nucleares (IPEN), Comissao Nacional de Energia Nuclear (CNEN), Atmospheric Chemistry Laboratory, 2242 Avenida Professor Lineu Prestes, Cidade Universitaria, Sao Paulo CEP 05508-000, Brazil

    • Luana S. Basso
    •  & Luciana V. Gatti
  5. School of Earth Sciences, The University of Bristol, Wills Memorial Building, Queen’s Road, Bristol BS8 1RJ, UK

    • Edward R. C. Hornibrook
  6. Department of Earth, Environmental and Geographic Sciences, Irving K. Barber School of Arts and Sciences, The University of British Columbia, Okanagan Campus, 1177 Research Road, Kelowna, British Columbia V1V 1V7, Canada

    • Edward R. C. Hornibrook
  7. National Institute for Space Research (INPE), Center for Earth System Science (CCST), Greenhouse Gas Laboratory (LaGEE), Av. Dos Astronautas 1758, Sao Jose dos Campos CEP 12227-010, Brazil

    • Luciana V. Gatti
  8. Ecosystems and Global Change Laboratory (LEMG-UFF)/International Laboratory of Global Change (LINCGlobal), Biomass and Water Management Research Center (NAB-UFF), Universidade Federal Fluminense (UFF), Avenido Edmundo March 24210-310, Niteroi/Rio de Janeiro, Brazil

    • Humberto Marotta
  9. Sedimentary and Environmental Processes Laboratory (LAPSA-UFF), Department of Geography, Universidade Federal Fluminense (UFF), Avenida General Milton Tavares de Souza 24210-346, Niteroi/Rio de Janeiro, Brazil

    • Humberto Marotta
  10. Environmental Biogeochemistry Laboratory, Federal University of Rondônia, Rondônia, Brazil

    • Wanderley Rodrigues Bastos
  11. Radioisotopes Laboratory, Biophysics Institute, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil

    • Olaf Malm
  12. School of Geography, University of Leeds, Woodhouse Lane, Leeds LS9 2JT, UK

    • Emanuel Gloor
  13. Global Monitoring Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration, 325 Broadway, Boulder, Colorado 80305, USA

    • John Bharat Miller


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S.R.P., V.G., A.E.-P. and D.B. conceived and designed the bottom-up measurement study. The Brazil expeditions (bottom-up measurements) in 2013 and 2014 were planned and organised by A.E.-P., O.M., W.R.B., R.B.P. and S.R.P. and carried out by S.R.P., R.B.P., H.M., L.S.B.C. and W.R.B. The δ13C-CH4 analysis was performed by E.R.C.H., who also interpreted those data. L.S.B.C. and C.M.S. identified the tree species in the 2014 Brazil expedition. The top-down measurement study was designed and carried out by L.S.B., L.V.G., J.B.M. and E.G. V.G. coordinated the integration of the various elements of the study. S.R.P., V.G., L.S.B., E.G., D.B., E.R.C.H. and A.E.-P. contributed to the writing of the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Sunitha R. Pangala or Vincent Gauci.

Reviewer Information Nature thanks C. Frankenberg, F. Keppler, P. Megonigal and the other anonymous reviewer(s) for their contribution to the peer review of this work.

Publisher's note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

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    Supplementary Information

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