Atmospheric oxidation capacity sustained by a tropical forest

Abstract

Terrestrial vegetation, especially tropical rain forest, releases vast quantities of volatile organic compounds (VOCs) to the atmosphere1,2,3, which are removed by oxidation reactions and deposition of reaction products4,5,6. The oxidation is mainly initiated by hydroxyl radicals (OH), primarily formed through the photodissociation of ozone4. Previously it was thought that, in unpolluted air, biogenic VOCs deplete OH and reduce the atmospheric oxidation capacity5,6,7,8,9,10. Conversely, in polluted air VOC oxidation leads to noxious oxidant build-up by the catalytic action of nitrogen oxides5,6,7,8,9,10 (NOx = NO + NO2). Here we report aircraft measurements of atmospheric trace gases performed over the pristine Amazon forest. Our data reveal unexpectedly high OH concentrations. We propose that natural VOC oxidation, notably of isoprene, recycles OH efficiently in low-NOx air through reactions of organic peroxy radicals. Computations with an atmospheric chemistry model and the results of laboratory experiments suggest that an OH recycling efficiency of 40–80 per cent in isoprene oxidation may be able to explain the high OH levels we observed in the field. Although further laboratory studies are necessary to explore the chemical mechanism responsible for OH recycling in more detail, our results demonstrate that the biosphere maintains a remarkable balance with the atmospheric environment.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Figure 1: OH recycling.
Figure 2: Model calculations (background) and measurements (circles) of HO x radicals over Suriname (4° N, 56° W) in October 2005.
Figure 3: Difference in OH in the boundary layer, calculated by including enhanced OH recycling in the model.

References

  1. 1

    Guenther, A. et al. Estimates of global terrestrial isoprene emissions using MEGAN (Model of Emissions of Gases and Aerosols from Nature). Atmos. Chem. Phys. 6, 3181–3210 (2006)

  2. 2

    Kesselmeier, J. & Staudt, M. Biogenic volatile organic compounds (VOC): An overview on emission, physiology and ecology. J. Atmos. Chem. 33, 23–88 (1999)

  3. 3

    Goldstein, A. H. & Galbally, I. E. Known and unexplored organic constituents in the Earth’s atmosphere. Environ. Sci. Technol. 41, 1515–1521 (2007)

  4. 4

    Levy, H. Normal atmosphere: large radical and formaldehyde concentrations predicted. Science 173, 141–143 (1971)

  5. 5

    Wang, Y., Jacob, D. J. & Logan, J. A. Global simulation of tropospheric O3-NOx-hydrocarbon chemistry, 3. Origin of tropospheric ozone and effects of non-methane hydrocarbons. J. Geophys. Res. 103, 10757–10767 (1998)

  6. 6

    Lelieveld, J., Peters, W., Dentener, F. J. & Krol, M. Stability of tropospheric hydroxyl chemistry. J. Geophys. Res. 107 10.1029/2002JD002272 (2002)

  7. 7

    Lawrence, M. G. et al. A model for studies of tropospheric photochemistry: description, global distribution and evaluation. J. Geophys. Res. 104, 26245–26278 (1999)

  8. 8

    Granier, C., Petron, G., Müller, J.-F. & Brasseur, G. The impact of natural and anthropogenic hydrocarbons on the tropospheric budget of carbon monoxide. Atmos. Environ. 34, 5255–5270 (2000)

  9. 9

    von Kuhlmann, R., Lawrence, M. G., Pöschl, U. & Crutzen, P. J. Sensitivities in global scale modelling of isoprene. Atmos. Chem. Phys. 4, 1–17 (2004)

  10. 10

    Jöckel, P. et al. The atmospheric chemistry general circulation model ECHAM5/MESSy: Consistent simulation of ozone from the surface to the mesosphere. Atmos. Chem. Phys. 6, 5067–5104 (2006)

  11. 11

    Field, C. B., Behrenfeld, M. J., Randerson, J. T. & Falkowski, P. Primary production of the biosphere: Integrating terrestrial and oceanic components. Science 281, 237–240 (1998)

  12. 12

    Terry, G. M., Stokes, N. J., Hewitt, C. N. & Mansfield, T. A. Exposure to isoprene promotes flowering in plants. J. Exp. Bot. 46, 1629–1631 (1995)

  13. 13

    Wildermuth, M. C. & Fall, R. Light-dependent isoprene emission. Plant Physiol. 112, 171–182 (1996)

  14. 14

    Singsaas, E. L., Lerdau, M., Winter, K. & Sharkey, T. D. Isoprene increases thermotolerance of isoprene emitting species. Plant Physiol. 115, 1413–1420 (1997)

  15. 15

    Penuelas, J., Lluisa, J., Asensio, D. & Munne-Bosch, S. Linking isoprene with plant thermotolerance, antioxidants and monoterpene emissions. Plant Cell Environ. 28, 278–286 (2005)

  16. 16

    Pöschl, U., von Kuhlmann, R., Poisson, N. & Crutzen, P. J. Development and intercomparison of condensed isoprene oxidation mechanisms for global atmospheric modelling. J. Atmos. Chem. 37, 29–52 (2000)

  17. 17

    Sander, R., Kerkweg, A., Jöckel, P. & Lelieveld, J. Technical note: The new comprehensive atmospheric chemistry module MECCA. Atmos. Chem. Phys. 5, 445–450 (2005)

  18. 18

    Saunders, S. M., Jenkin, M. E., Derwent, R. G. & Pilling, M. J. Protocol for the development of the Master Chemical Mechanism, MCM v3 (Part A): tropospheric degradation of non-aromatic volatile organic compounds. Atmos. Chem. Phys. 3, 161–180 (2003)

  19. 19

    Hasson, A. S., Tyndall, G. S. & Orlando, J. J. A product yield study of the reaction of HO2 radicals with ethyl peroxy (C2H5O2), acetyl peroxy (CH3C(O)O2), and acetonyl peroxy (CH3C(O)CH2O2) radicals. J. Phys. Chem. 108, 5979–5989 (2004)

  20. 20

    Jenkin, M. E., Hurley, M. D. & Wallington, T. J. Investigation of the radical product channel of the CH3COO2 + HO2 reaction in the gas phase. Phys. Chem. Chem. Phys. 9, 3149–3162 (2007)

  21. 21

    Thornton, J. A. et al. Ozone production rates as a function of NOx abundances and HOx production rates in the Nashville urban plume. J. Geophys. Res. 107 doi: 10.1029/2001JD000932 (2002)

  22. 22

    Kuhn, U. et al. Isoprene and monoterpene fluxes from Central Amazonian rainforest inferred from tower-based and airborne measurements, and implications on the atmospheric chemistry and the carbon budget. Atmos. Chem. Phys. 7, 2855–2879 (2007)

  23. 23

    Tan, D. et al. HOx budgets in a deciduous forest: Results from the PROPHET summer 1998 campaign. J. Geophys. Res. 106, 24407–24427 (2001)

  24. 24

    Karl, T. et al. The tropical forest and fire emissions experiment: Emission, chemistry and transport of biogenic volatile organic compounds in the lower atmosphere over Amazonia. J. Geophys. Res. 112 10.1029/2007JD008539 (2007)

  25. 25

    Williams, J., Yassaa, N., Bartenbach, S. & Lelieveld, J. Mirror image hydrocarbons from tropical and boreal forests. Atmos. Chem. Phys. 7, 973–980 (2007)

  26. 26

    Di Carlo, P. et al. Missing OH reactivity in a forest: Evidence for unknown reactive biogenic VOCs. Science 304, 722–725 (2004)

  27. 27

    Goldstein, A. H. et al. Forest thinning experiment confirms ozone deposition to forest canopy is dominated by reaction with biogenic VOCs. Geophys. Res. Lett. 31 10.1029/2004GL021259 (2004)

  28. 28

    Ciccioli, P. et al. Emission of reactive terpene compounds from orange orchards and their removal by within-canopy processes. J. Geophys. Res. 104, 8077–8094 (1999)

  29. 29

    Ganzeveld, L. N. et al. Global soil-biogenic NOx emissions and the role of canopy processes. J. Geophys. Res. 107 doi: 10.1029/2001JD001289 (2002)

Download references

Acknowledgements

We are grateful to the GABRIEL campaign team: S. Bartenbach, C. Becker, H. Bozem, S. Engemann, H. Franke, S. Gebhardt, C. Gurk, H. Hoeseni, R. Hofmann, T. Klüpfel, R. Königstedt, D. Kubistin, R. Maser, D. Noorden, U. Parchatka, D. Rodrigues, M. Rudolf, B. Scheeren, C. Schiller, V. Sinha, A. Stickler, B. Tan, P. van Velthoven, T. Warsodikromo and G. Wesenhagen. We thank the Modular Earth Submodel System (MESSy) team for model support, in particular P. Jöckel and H. Tost, and P. J. Crutzen for comments on the manuscript.

Author information

Correspondence to J. Lelieveld.

Supplementary information

Supplementary information

The file contains Supplementary Methods and Results, Supplementary Figures S1-S4 with Legends, Supplementary Table S1 and additional references. (PDF 1461 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Lelieveld, J., Butler, T., Crowley, J. et al. Atmospheric oxidation capacity sustained by a tropical forest. Nature 452, 737–740 (2008). https://doi.org/10.1038/nature06870

Download citation

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.