1. Emissions of Volatile Organic Compounds by Plants Carbon Metabolism and Atmospheric Chemistry Kolby Jardine Amazon-PIRE Field Course June 2010

2. Composition of the Atmosphere Gases

3. What are VOCs? Atmospheric Concentrations < 20 ppb

4. Dominant primary VOC sources in the Atmosphere Biomass Burning Urban/Industrial Emissions Biogenic Emissions VOC: volatile organic compound e.g. hydrocarbons

5. From www.igac.noaa.gov Atmospheric Impacts of VOCs 1)Climate 2)Air Quality

6. Why the interest in BVOCs? Reactive Aerosols Biogenic VOCs Anthropogenic VOCs

7. Organic Aerosol TRACE GASES oxidize Ozone H 2 CO CO CH 4 Secondary Organic Aerosol Isoprene Monoterpenes Sesquiterpenes Oxygenated VOC

8. Simplified Catalytic Cycle of Tropospheric Ozone Production Players: VOC: volatile organic compounds NO x : nitrogen oxides RO 2: peroxy radicals hv: radiation RO 2 (HO 2 ) ROVOC emissions OH O2O2 Fuel NONO 2 NO x emissions OH HNO 3 O2O2 hv Ozone Catalyst fossil fuel combustion biomass burning (soil, lightning) O*

9. How Many Species are Produced during the Oxidation of Hydrocarbons? Aumont et al., ACPD, 2005 Heptane: 10 5 – 10 6 intermediates >10 6 reactions Isoprene: 10 4 intermediates >10 4 reactions O 3 + hv O( 1 D) + O 2 O( 1 D) + H 2 O OH + OH OH – The Detergent of the Atmosphere During the 18th century engineers already knew that coal combustion would release CO as a toxic substance. They estimated that within ~1000-2000 years the atmosphere would fill up with high enough levels of CO so that any life on the planet would die! Luckily this won’t happen due to the presence of OH!

10. Tower-based flux meas. systems Years Days Hours TIME SCALE SPATIAL SCALE Leaf Canopy LandscapeRegional/global Enclosure flux meas. systems Analysis using ambient concentrations, isotopes and oxidation products Satellite data (e.g. HCHO) Aircraft and blimp-based flux measurement systems Process studies Tools for Investigating Trace Gas Fluxes Seconds Regional Characterization

11. Measurement techniques

12. Amazon VOCs Emitted from Vegetation >1000 compounds identified tropics: 100s species / ha Image from ksuweb.kennesaw.edu

13. Ray Fall 1999 Volatile Metabolite Emissions from Plants 1)Environmental Stresses (desiccation, UV light, oxidants) 2) Reproduction and growth 3) Phytohormones (semiochemicals) 4) Biological stresses (herbivores) 5) Primary carbon and energy metabolism

14. Primary Carbon Metabolism in Plants RUBISCO PEP carboxylase Respiration Photorespiration Fermentation CO 2 Photosynthesis Are VOC emissions related to these processes?

15. Pyruvic acid; the link between primary and secondary carbon metabolism Ethanol Acetaldehyde Acetic Acid Pyruvic Acid Acetone Isoprene Sesquiterpenes Monoterpenes

18. Response of Isoprene Emissions to Temperature Guenther et al. empirical algorithms

19. Response of Isoprene Emissions to Light

20. Response of Isoprene Emissions to Atmospheric CO2 Concentrations

21. F = g*ΔC, where ΔC = [isoprene] i – [isoprene] a atmosphere Leaf [isoprene] a production [isoprene] i [isoprene] a production [isoprene] i [isoprene] a production [isoprene] i

22. F = g*ΔC, where ΔC = [AA] i – [AA] a [AA] a atmosphere Leaf consumption production [AA] i consumption production [AA] i

23. Summary of Biosphere-Atmosphere Feedbacks From Pasifico et al., 2009

24. Thanks! Paulo Artaxo (University of Sao Paulo) Trina Shartsis (University of Arizona) Scott Saleska (University of Arizona) Travis Huxman (University of Arizona) Angie Jardine (University of Arizona) Alex Guenther (NCAR) Thomas Karl (NCAR) Peter Harley (NCAR)